Seminar Topics

4G WIRELESS NETWORK

2012-06-27T03:40:00.000-07:00

4G WIRELESS NETWORK

Abstract

The Third-Generation (3G) wireless technologies offer wireless web, SMS, MMS, EDGE, WCDMA, GPRS etc. 4G is a packet switched technology, uses bandwidth much more efficiently, allowing each user's packets to compete for available bandwidth. It solves the non-standardization problems associated with 3G. Data transfer rate will be 20 to 100 Mbps, which is 10 to 50 times than 3G and 10-20 times faster than ADSL. Operating frequency range will be 3 to 10 GHz and the IPv6 protocol will be used. In this paper, fundamentals of 4G and their various proposed architectures are explained. In India it can be used to network rural and urban areas, reduce cost of communication, flourish educational activities, facilitate research and development, faster internet connectivity, more cellular options, real time information systems, crisis management, Tele-medicines and many more. The present 3G networks need not to be discarded, and can be used in conjunction with 4G technology. There are various architectures

Proposed that can be used to deploy 4G.

1. Introduction

The fourth-generation wireless (4G) technology implements designs that will take the wireless telecommunication industry beyond 2010. The infrastructure of the 4G will function on top of the current existing CDMA, GSM and TDMA. It extends the 3G capabilities These technical opportunities strengthen the user mobility and encourage the deployment of the mobile technologies for the development of various (mobile) applications providing information, orientation (routing) and other helpful services.

It will deliver superior quality video and data, in addition to voice. It also solves the non-standardization problems associated with 3G networks for voice, video and data transmission. The data transfer rate is 20 to 100 Mbps, which will be 10 to 50 times those offered by 3G links and 10-20 times faster than standard ADSL (Asymmetric Digital Subscriber Line) services. The operating frequency ranges between 3 to 10 GHz and the IPV6 protocol used will be used. High-definition television programming through wireless broadband connections, Internet-based multi-channel video and higher mobile Internet will become a reality. The Defense Advanced Research Projects Agency (DARPA) in the US originally conceived of 4G.

2. Need of 4G:

· 3G performances insufficient to meet high performance future needs.

· Multiple incompatible standards. Global mobility and service portability required.

· Need for hybrid networks for both WLAN and cellular network design.

· Technology to utilize newly found modulation methods.

· Need for All IP network with converged voice and data capability.

· Wider bandwidth.

3. Characteristics

3.1 End-to-End Internet Protocol (IP):.

It will provide access through a collection of radio interfaces, seamless roaming/handover and the best-connected service, combining multiple radio access interfaces (such as WLAN, Bluetooth and GPRS) into a single network that subscribers may use. It allows any mobile device to seamlessly roam over different wireless technologies automatically, using the best connection available for the intended use. Users will have access to different services, increased coverage, the convenience of a single device, one bill with reduced total access cost, and more reliable wireless access even with the failure or loss of one or more networks.

3.2 Peer-to-Peer networks: In this system, every device is both a transceiver and a router/repeater for other devices in the network, elimination of a single node does not disable the network. 4G can be defined as "wireless ad hoc peer-to-peer networking."

4. Significance of 4G

In 4G networks, users joining the network add mobile routers to the network infrastructure. Network capacity and coverage is dynamically shifted to accommodate changing user patterns. Wherever the concentration of people is more in one area, additional routes are created, thus enabling additional access to network capacity. Users will automatically hop away from congested routes to less congested routes. This permits the network to dynamically and automatically balance capacity and increase network utilization. As number of users increases, the service improves for all users.

5. Features of 4G

High speed: 100 Mbps in stationary mode with an average of 20 Mbps when traveling.

High network capacity: Should be at least 10 times that of 3G systems.

Fast/seamless handover across multiple networks: 4G wireless networks should support global roaming across multiple wireless and mobile networks,

Next-generation multimedia support: fast speed and large volume data transmission at a lower cost than today.

MIMO techniques : The benefit of array or multiple antennas for spatial diversity has long been realized. Yet only recently were they combined with advanced coding techniques to from extremely efficient MIMO (Multiple Input Multiple Output) systems.

Wireless access technologies: OFDMA (Orthogonal Frequency – Division Multiple Access ) and MC-CDMA (Multiple Carrier CDMA) are the main contender for the future system. Another more radical access scheme for the downlink, yet better in terms of throughput, is a single queue packet based system

6. Future applications

Sensors on public vehicles Cameras in traffic lights

Tele-medicine: a paramedic assisting a victim of a traffic accident in a remote location could access medical records (e.g., x-rays) and establish a videoconference so that a remotely-based surgeon could provide "on-scene" assistance.

Crisis-management applications: In case of any natural disasters where the entire communications infrastructure has collapsed, restoring communications quickly is essential. With 4G networks it can be set up in a matter of hours. In comparison, it may take days or even weeks to re-establish communications capabilities when a wire line network fails.

7. Possible Architectures on 4G

One of the most challenging problems facing deployment of 4G technology is how to access several different mobile and wireless networks. Three possible architectures: using a multi-mode device, an overlay network, or a common access protocol.

7.1 Multimode devices (Fig2):

A single physical terminal with multiple interfaces to access services on different wireless networks. The multimode device architecture may improve call completion and expand effective coverage area. It should also provide reliable wireless coverage in case of network, link, or switch failure. The device itself incorporates most of the additional complexity without requiring wireless network modification or employing inter-working devices. Each network can deploy a database that keeps track of user location, device capabilities, network conditions, and user preferences. The handling of quality-of-service (QoS) issues remains an open research question.

Fig 2. A multimode device lets the user, device, or network initiate handoff between networks without the need for network modification or interworking devices.

7.2 Overlay mode (Fig 3) :

In this architecture, a user accesses an overlay network consisting of several universal access points. These UAPs in turn select a wireless network based on availability, QoS specifications, and user-defined choices. A UAP performs protocol and frequency translation, content adaptation, and QoS negotiation-renegotiation on behalf of users. The overlay network, rather than the user or device, performs handoffs as the user moves from one UAP to another. A UAP stores user, network, and device information, capabilities, and preferences. Because UAPs can keep track of the various resources a caller uses, this architecture supports single billing and subscription. Satellite network Fixed wireless network.

Fig 3. An overlay network—consisting of several universal access points (UAPs) that store user, network, and device information—performs a handoff as the user moves from one UAP to another.

7.3 Common access protocol (Fig4):

This protocol becomes viable if wireless networks can support one or two standard access protocols. One possible solution, which will require interworking between different networks, uses wireless asynchronous transfer mode. To implement wireless ATM, every wireless network must allow transmission of ATM cells with additional headers or wireless ATM cells requiring changes in the wireless networks. One or more types of satellite-based networks might use one protocol while one or more terrestrial wireless networks use another protocol. Wireless LAN Cellular network

Fig 4. A device capable of automatically switching between networks is possible if wireless networks can support a common protocol to access a satellite-based network and another protocol for terrestrial networks.

7.4 The proposed Architecture for 4G:

Fig 5. Several networks can be converged with the 4G networks providing all kinds of services to the users.

Fig 5 shows the real scenario of how 4G can really mingle with the present technology and scale upward to give more bandwidth and lower the cost. Security will be a major issue when several networks will be connected together.

A legal subscriber can view various television networks in his/her handset, browse through to the internet at a very high speed connectivity, send e-mails remotely, reserve train or air tickets from any part of the country, stay connected with their professors and many more things at a very reduced cost.

Repeaters will give mobile Internet at a speed of 20mbps; optical cables can also contribute to the data transmissions. Different organizations can stay connected with each other and their customers,

8.Conclusion

4G is the next upcoming wireless technology. It holds a lot of promises in solving today’s problems and tomorrows needs. 4G will also make worldwide roaming using a single handheld device. 4G networks may eventually deliver on all the promises. At times, it seems that technological advances are being made on a daily basis. These advances will make high-speed data/voice-over-Internet-protocol (VoIP) networks a reality. In the meantime, it is important for industry to develop a strong 3G offering that is palatable for the general public. Equally as important, industry must ensure that expectations are realistic and that services meet and exceed those expectations. If all goes according to what the industry envisions, it may be sooner, rather than later that we will see wireless communications evolve. This evolution will give the general public as well as the public safety community amazing functionality from the convenience of a single handheld device.

References:

· International forums on 4G mobile, By : Lucant technologies, bell labs innovations

· Fraunhofer Institute for Secure Telecooperation (SIT) August 02. [bayarou|rohr]@sit.fraunhofer.de

· Information Raining for Mobile Hotspots in 4G Wireless Networks : Shahrokh Valaee , Department of Electrical and Computer Engineering ,University of Toronto, Toronto, Ontario, Canada, Email: valaee@comm.utoronto.ca

SMART EYE IN NANO TECHNOLOGY

2012-06-26T05:49:00.000-07:00

SMART EYE

NANO TECHNOLOGY

(AN INNOVATIVE APPROCH ON E-EYE)

Abstract:

In conventional electronic eye,micro photodiode is used for converting the light energy to electrical pulses.for that there are 50-100 electrodes are used.but the amount of diode used here are not enough to view the clear image.To get clear image 1000 of electrodes are required.If we increase the number of electrodes in amount the size of the device become large.this will be a drawback of an electronic eye.we presents a smart eye that eliminates the drawback of an conventional electronic eye.Instead of using microphotodiode,nanowires [300nm-500nm] are used in smart eye.since the nanowires having a verygood opto electronic property,it is used for detection and transmission of light and the size of the nonowire is very less as compare to microphotodiode.we can insert 1000 nanowires within the prescribed space allotted for inserting the [50-100] microphotodiode.Here nanolens is used instead of microlens to get high resolution.Hence the slightless person gets the clear image of the particular object through smart eye.Key words:

electronic eye, microphotodiode, electrodes,nanowire, smart eye.

Introduction:

Research on microelectronics, magnetic, nanotechnology, on-board data processing, etc has now made itpossible to manufacture a new generation of sensors and other electronics devices .further the research works on integration and imaging technology has led to the development of very small size devices that overcome functional complexity of earlier generation equipment .the technology has a range of application in detection of diseases and abnormalities in medical fields. These new generation biomedicalequipment are not only very small and userfriendly but work with great precision and produce images of excellent resolutio even a few years ago people could not think of such equipment .one of suchdevice is smart eye.

An electronic eye:

an effective navigation system would improve the mobility of millions of blind people all over the world. a new “eye” developed which will allow blind people to cross busy roads in total safety for the first time. the “electronic eye”, which would be mounted on a pair of glasses, will be capable of detecting the existence and location of a pedestrian crossing, and at the same time measure the width of the road to the nearest step and detect the colour of the traffic lights. but in most of the the time the image produced by the electronic eye is not clear due to the microphotodiode electrodes which is less in amount.

The eyeball is an optical device for focusing light :

The mammalian eyeball is an organ that focuses a visual scene onto a sheet of specialized neural tissue, the retina, which lines the back of the eye. Light from a scene passes through the cornea, pupil, and lens on its way to the retina. The cornea and lens focus light from objects onto photoreceptors, which absorb and then convert it into electrical signals that carry information to the brain. Two pockets of transparent fluid nourish eye tissues and maintain constant eye shape: these are the aqueous and vitreous humors, through which the light also passes. The lens projects an inverted image onto the retina in the same way a camera lens projects an inverted image onto film; the brain adjusts this inversion so we see the world in its correct orientation. To control the images that fall upon our retinas, we can either turn our heads or turn our eyes independently of our heads by contracting the extraocular muscles, six bands of muscles that attach to the tough outside covering, or sclera, of the eyeball and are innervated by cranial nerves.

The cornea and lens bend or refract light rays as they enter the eye, in order to focus images on the retina. The eye can change the extent to which rays are bent and thus can focus images of objects that are various distances from the observer, by varying the curvature of the lens. The ciliary muscle accomplishes this by contracting to lessen tension on the lens and allowing it to round up so it can bend light rays more, or relaxing for the opposite effect. This ciliary muscle is smooth or non-voluntary muscle-you cannot "decide" to contract or relax it as you do the skeletal muscle in a finger or facial muscle.

Colour filter:

A color filter array (CFA) is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information
Color filters are needed because the typical photosensors detect light intensity with little or no wavelength specificity, and therefore cannot separate color information.Since sensors are made of semiconductors they obeysolid-statephysics.The color filters filter the light by wavelength range, such that the separate filtered intensities include information about the color of light. For example, the Bayer filter gives information about the intensity of light in red, green, and blue wavelength regions. The raw image data captured by the image sensor is then converted to a full-color image by a demosaicing algorithm. The sensor uses a different structure such that a pixel utilizes properties of multi-junctions to stack blue, green, and red sensors on top of each other. This arrangement does not require a demosaicing algorithm because each pixel has information about each color

The retina originates from the brain and contains photoreceptors for detecting light :

The eye is formed during embryonic development by a combination of head ectoderm and neural tube tissue, the latter forming the retina. Thus, the retina is not a peripheral sensory organ like skin touch receptors or taste buds on the tongue, but rather it is an outgrowth of central nervous tisse. Because of this origin, the retina has layers of neurons, internal circuits, and transmitters characteristic of the brain: it is a bit of the brain that has journeyed out, literally, to have a look at the environment.

The photoreceptors in the retina are of two types: rods and cones, so named because of their shapes. These cells are actually specialized neurons that detect light. Embedded in stacks of cell membranes in the distal portions of rods and cones are molecules that absorb certain wavelengths of light. These molecules are called photopigments and are composed of two parts: a large trans-membrane protein, an opsin, and a smaller chromophore, which is a metabolite of Vitamin A called 11-cis-retinal. The chromophore, which is embedded in the opsin, absorbs light; in so doing it undergoes a shape change. This shape change in turn activates the opsin, setting off a cascade of events that leads to a change in the electrical state of a rod or cone cell

membrane. This change in the rod conecell membrane is then conducted via the rod or cone axon to other neurons in the retina, and from there to the brain.

Rods function in dim light:

In dim light, we use our rods, which cannot work in bright light. Rods outnumber cones (120 million rods and about 6 million cones in each retina) and they amplify a light signal much more than cones. the absorption of even a single quantum of light can trigger a chromophore shape change in one molecule of rhodopsin in a rod, leading to signal transmission. For transmission to occur, this initial tiny event must be amplified: the activated molecule of rhodopsin converts several thousand molecules of the next enzyme in the cascade to the active form, and this amplification continues until the electrical potential of the cell membrane changes and neurotransmitter release is affected. Cones, on the other hand, must each absorb hundreds of photons in order to send signals.

Another retinal mechanism that helps us to see in dim light or to see a tiny amount of light in the dark is the convergence of rod cell signals onto other retinal neurons. Many rods (up to 150) synapse onto the same target neurons, where the signals are pooled and reinforce one another, increasing the ability of the brain to detect a small amount of light. (A synapse is a contact between a neuron and another cell where an electrochemical signal [most commonly] is transmitted to the second cell.) This convergence amplifies weak signals, but spatial resolution is lost becauseresponses are averaged.

In order for our eyes to make the transition to dim light, rods must adapt after being saturated with light in brighter conditions. Dark adaptation of rods takes seven to ten minutes: during this time rhodopsin molecules, in which the chromophore components have changed to the activated state, return to the non-activated state so that they are able once again to register changes in illumination. Other changes also occur in adaptation to dark or dim conditions, including enlarging or dilating of the pupil, which is controlled by the autonomic nervous system.

Cones mediate day vision:

Our vision in bright or moderate light is completely mediated by cones, which provide color vision, black and white vision, and high acuity, the ability to discern fine detail. Like rods, cones contain an opsin and the chromophore 11-cis-retinal, but the opsins differ from rhodopsin so that each cone is responsive to one of three colors: red, green or blue. Cones are spread throughout the retina but are especially concentrated in a central area called the macula. At the center of the macula is the fovea, where only cones (no rods) are found, and these are densely packed. When we want to read or inspect fine detail, we move our heads and eyes until the image of interest falls onto the fovea. Because the fovea lacks rods, it is easier to see in dim light by looking to the side of an object instead of directly at it. You can test this by looking to the side of a faint star so that its image falls on rods, rather than on the fovea where it probably will not register. When you look directly at the faint star, it disappears.

In contrast to the wiring of rods, only a few cones converge onto other retinal neurons to average their signals, so cones provide better spatial resolution. In fact, each cone in the fovea synapses onto only one neuron in the next relay in the retina. This gives this area the ability to transmit fine detail, such as we use in reading.

Thus, cones mediate day vision and rods take over in dim light and at night. Both rods and cones can operate at the same time under some conditions: in dim or dark conditions, rods are most sensitive, but cones respond to stimuli that are sufficiently bright. This is why we can see the colors of neon lights on dark nights.

Nanolens:

Nanoscale lenses with superhigh resolution using a novel self-assembly method. So far, they've demonstrated that the tiny lenses can be used for ultraviolet lithography, for imaging objects too tiny for conventional lenses, and for capturing individual photons from a light-emitting nanostructure called a quantum dot.

Self-assembly line: The spherical nanolenses shown in this electron microscope image have separated from the crystalline nanotubes underneath them. The structures spontaneously form when a solution of cup-shaped organic molecules is allowed to evaporate. The limits on the resolution of both light microscopes and the photolithographic instruments used by the semiconductor industry are a consequence of light's fundamental properties. Because of the way light scatters, or diffracts, even a perfect lens cannot distinguish two objects that are closer together than half the wavelength of the light used to image them. nanolens overcome the diffraction limit because of their size. The lenses are flat on one side and spherical on the other and range in diameter from about 50 nanometers to three micrometers. Nanolens makes color imaging of nano objects possible Optical imaging of materials is full with rich physical, chemical and biological information about the sample, because the optical energies in the visible range coincide with the atomic and molecular transition energies of many materials. Apart from the topographical information, the optical image therefore contains information about intrinsic properties of a material. However, the wave nature of light prevents the light to focus in a volume smaller than half of the wavelength, which is about 200-300 nm for visible light. Therefore, it is almost impossible to image nanomaterials, which could be a few nanometers in size, using optical imaging process.

This metallic nanolens is capable of manipulating light in such a way that an optical image of nanoscale objects can be obtained in the visible range.

"We have demonstrated that our nanolens can transfer color images of nanoscale objects over distances of at least micrometer scale with a sufficient amount of magnification for far-field observation "We believe that, in principle, the image can be transferred over even longer distances without any significant loss. The proposed nanolens could potentially be a strong imaging tool, for example, for observing individual viruses and other nano-entities in the far field."

A metal always has free change carriers – called plasmons – moving collectively on the surface of the metal. Plasmons play a large role in the optical properties of metals since they can interact with light, and somehow manipulate the predicted nature of light.

One of the most important restriction was that only one particular wavelength that resonates with the plasmons can be used in imaging, which essentially means that a normal colored object – which emits many wavelengths – would not make a sharp image. The other problem was that the plasmons lose energy quite quickly as they propagate, making it impossible to have a long distance image transfer. Last, but not the least, the size of the image remained the same as the object (in the nanometer scale), and thus it was impossible to record these images."The design of a nanolens that involves a tapered stacked arrangement of silver nanorods. The layers are separated by nano-gaps, which prevents the propagation of plasmons, resulting in extremely low loss of energy and thus making long distance imaging possible. It appears that a gap size of 10 nm gives the optimum value for efficient imaging.

.Color imaging requires the resonance to be broad, so that a large part of the visible spectrum can be covered. "Our simulation results show that with an increasing number of layers, the number of resonant modes also increases, and they tend to gather in the vicinity of the fundamental mode of the corresponding unit rod" "Moreover, the nanolens can also magnify the image so that the image can be large enough for normal viewing."

This technique has the potential to be an indispensable imaging tool, in particular, for bio-medical applications, where individual viruses and other nano-objects of different colors could be simultaneously imaged at a long distance and could be detected at sufficient magnification with usual microscopes and detectors, such as a CCD camera."A potential challenges lies in the accurate growth of silver nanorods with precise geometry, which involves growth of stacked arrays of silver nanorods where the arrays are separated with specific nano-gaps and are arranged in a tapered manner.

NANOWIRE:

In order to rectify this problem nanowires are used in smart eye . semiconductor nanowires of high purity and crystallinity hold promise as building blocks for opto-electronical devices at the nanoscale.. they are commonly grown via a vapor-liquid-solid (vls) mechanism in which metal (nano) droplets collect the semiconductor precursors to form a solution which, when saturated, leads to the growth of a wire underneath the droplet.

after a brief discussion of this general mechanism, the growth of inp and zno nanowires is detailed. the grown inp nanowires have an integrated alloy particle and have on average diameters of 50 nm and lengths of 10 μm. zno nanowires grown on silicon oxide covered substrates exhibit an integrated alloy particle, have diameters in the 50-100 nm range and lengths of up to 50 μm. in contrast, under the same growth conditions, zno nanowires grown epitaxially on al2o3 substrates do not have an integrated gold particle and exhibit diameters mostly in the 100-300 nm range with lengths of up to 10 μm. finally it is shown that using a method that is widely applicable for nanostructures, zno nanowires can be doped with cobalt ions which is an important step towards room-temperature ferromagnetic semiconducting nanowires for spintronic applications.

nanowire-as a detector:

as humans, we are all born equipped with a pair of single-photon detectors-our eyes. actually, the story is a bit more complicated because, while the rod cells on the retina respond to the absorption of a single photon by generating a small current, the brain requires about ten photons to be absorbed before registering a flash of light.

for the applications in communications and metrology that we are interested in, however, the eye would not be a very good choice for a photodetector. first of all, the eye is insensitive to infrared (ir) light and responds to visible light only on millisecond timescales. in addition, high optical loss due to reflection and transmission at the ocular interfaces of the cells lowers the detection efficiency. finally, the eye requires an integrated, highly sophisticated, and thermally stable package-the human body-to maintain its performance. these same challenges-sensitivity, speed, optical loss, and packaging-must be addressed by any photodetector technology for it to be of use.

Infrared Detection:

though other ir single-photon detectors exist, they also have shortcomings. avalanche photodetectors (apds) exhibit impressively low jitter (the error in the time-of-arrival information of the photon) and good detection efficiencies, but are plagued by relatively long (microsecond timescale) reset times and high dark-count rates (the rate at which the detector fires even when a photon is not incident). photomultiplier tubes (pmts) can provide very fast reset times, but suffer from low detection efficiencies in the technically important-to the communications industry-ir region of the spectrum around 1550 nm.

Operation of the Nanowire Detector:

The currently theorized operating principle of the nanowire detector is surprisingly straightforward. when a photon is absorbed by a superconducting wire it creates a hot spot-a small region where the superconductor becomes resistive. a current running through the wire will avoid that hot spot, preferring instead the zero-resistance regions outside the perimeter and on either side of the spot-regions we call the “sidewalks” of the device. the current density in these sidewalks therefore increases. but superconductors also have the interesting and useful property that they only superconduct up to a maximum current density, known as the critical current density. above this current, they become resistive. if the biasing current is initially set very close to the critical current, the absorption of a photon will trigger the entire cross section of the wire to switch into the resistive state and a voltage will appear across the device terminals.

figure: operation of the superconducting nanowire single-photon detector is based on how the niobium nitride nanowire responds to an incident photon as it creates a resistive “hot spot” on the detector surface.

while this mechanism of operation may seem simplistic, great care must be taken to realize a device with the observed performance. the starting material for our work (and the majority of the experimental work on this kind of detector to date) is 4-nm-thick niobium nitride material grown epitaxially on a sapphire substrate. state pedagogical university.

after material growth, we pattern the substrates using electron-beam lithography and a series of custom-developed nanometer-length-scale etching, deposition, and optical-lithography steps. the electron-beam lithography is a particularly challenging aspect of the work, as the variation in the device linewidth must be kept below a few percent. this is accomplished using hydrogen silsesquioxane (hsq), an electron-sensitive spin-on-glass resist with very low line-edge roughness and high resolution. the hsq material has the very useful property that after exposure and development it is also a good optical material-similar to silicon dioxide (sio2)-and so we use it throughout the process as part of the final integrated optical device, as well as an electron resist.

figure: a conceptual illustration (top) of a superconducting-nanowire single-photon detector being illuminated with laser light shows the microcavity consisting of a nanowire layer, a silicon-like optical-material spacer (above the nanowire layer), and a gold mirror (above the spacer). the laser beam should be smaller in width than the final detector (although the laser beam is currently somewhat wider). a scanning-electron micrograph (bottom) shows a 90-nm-wide niobium nitride nanowire pattern.

device testing is as challenging as fabrication: we have screened several hundred devices in the course of this work at temperatures down to 1.7 k. the detectors must also be packaged carefully, to reduce electrical noise in the readout and biasing circuits, and to couple light efficiently onto the detector surface.

SCANNING TUNNELING MICROSCOPE:

An instrument for producing surface images with atomic-scale lateral resolution, in which a fine probe tip is scanned over the surface at a distance of 0.5–1 nanometer, and the resulting tunneling current, or the position of the tip required to maintain a constant tunneling current, is monitored.

Scanning tunneling microscopes have pointed electrodes that are scanned over the surface of a conducting specimen, with help from a piezoelectric crystal whose dimensions can be altered electronically. They normally generate images by holding the current between the tip of the electrode and the specimen at some constant value by using a piezoelectric crystal to adjust the distance between the tip and the specimen surface, while the tip is piezoelectrically scanned in a raster pattern over the region of specimen surface being imaged. By holding the force, rather than the electric current, between tip and specimen at a set-point value, atomic force microscopes similarly allow the exploration of nonconducting specimens. In either case, when the height of the tip is plotted as a function of its lateral position over the specimen, an image that looks very much like the surface topography results.

It is becoming increasingly possible to record other signals (such as lateral force, capacitance, scan-related tip displacement, temperature, light intensity, or magnetic resonance) as the tip scans. For example, modern atomic force microscopes can map lateral force and conductivity along with height, while image pairs from scanning tunneling microscopes scanning to and fro can provide information about friction as well as topography.

Scanning tunneling microscopes make it possible not just to view atoms but to push them and even to rearrange them in unlikely combinations (sometimes whether or not these rearrangements are desirable). A few considerations of scale are important in understanding this process. Atoms comprise a positive nucleus and a surrounding cloud of negative electrons. These charges rearrange when another atom approaches, with unlike charges shifting to give rise to the van der Waals force of attraction between neutral atoms. This force makes gravity (and most accelerations) ignorable when contact between solid objects in the micrometer size range and smaller is involved, since surface-to-volume ratios are inversely proportional to object size.

The electric field in the scanning tunneling microscope allows plucking as well, in which adsorbed or substrate atoms are removed and transferred to the electrode tip with a suitable voltage pulse. Because the electric field from the tip falls off less rapidly with separation than do van der Waals forces, the most weakly attached nearby atom rather than the nearest may end up being removed. One solution to this problem is a hybrid approach. By invoking the tip electric field for bond breaking only when the tip is sufficiently close to the target atom that the van der Waals forces contribute as well, atoms on silicon could be singly removed and redeposited at will.
A third kind of selective bond breaking was also demonstrated. It involved the selective breaking of silicon-hydrogen bonds using electron energies below those necessary to break bonds directly. Since the desorption probability was observed to vary exponentially with the tip-specimen current, it is believed that vibrational heating from inelastic electron tunneling mediated the chemical transition in this work. This work involves bond alteration at the level of signal atoms, the ultimate frontier for lithographic miniaturization.Visual information travels from retinal ganglion cells to the brain:After converting light into electrical signals in their cell membranes, rods and cones transmit this information to other neurons in internal circuits in the retina for processing. From these cells, messages go to the final retinal station, the ganglion cells, whose axons exit the eyeball at the optic disc and form the optic nerve, which contains about one million axons. Because all the nerve fibers converge at the optic disc, no rods or cones are in this area and it forms a "blind spot" on the retina:

Within the optic nerve, a defined group of axons from each eye crosses over to join the opposite optic nerve at the optic chiasma
so each side of the brain receives visual information from both eyes. After the chiasma, retinal axons go to one of three areas: two of these are in the midbrain and one is in the thalamus. The information going to the midbrain does not reach conscious levels but rather produces pupillary reflexes (which are controlled by the autonomic nervous system) and eye movements. In the thalamus, ganglion cell axons transmit signals to neurons in the lateral geniculate nucleus (LGN) where information is processed and then carried by LGN axons to the primary visual cortex in the occipital lobe of the cerebrum. These cortical cells then send messages to other "higher" cortical areas.

OPERATION:

The external image is capture by the CCD sensors placed in the eye glasses then it sends the digital pulse through laser beam to the colour filter which is the first part in retina implant it allows the particular colour to the nano lens .nano lens focus the images and that image will be send to nanowires..

nanowires detect the input image signal and simulate the phosphenes this result the electric signal is producerd at the output of nanowires .this electrical signal is amplified and it is given to STM tip .it has sharp tip at one end the electrical signal activates the cell in retina then this signal is send to brain through nerves so the blind person can able to see the image.

CONCLUSION:

Sufficiently advanced technologies developed to treat diseases will inevitably morph into the technologies that will enhanced function .research on artificial implant for blindness is laying the groundwork for the eventual development of vastly superior, artificially enhanced eyesight. The smart eye can also be used in camera for remote monitoring for safety, identification and biometrics purposes. The amazing optical properties of nanowires enhance the efficiency of electronic eye. So there is no doubt that smart eye plays a major role in enhancing the eyesight of sightless person .

REFERENCES:

1.g.n.goltsmam,o.okunuv”picosecond superconducting single photon optical dectector.

2.s.denny,”medical electronics “-fourth edition

3.www.opticinfobase.com

A GRID SYSTEM OFFERS EFFICIENT VIRTUAL ENVIRONMENT

2012-06-26T05:20:00.000-07:00

A GRID SYSTEM OFFERS EFFICIENT VIRTUAL ENVIRONMENT

Abstract:

Grid technologies can allocate resources to applications dynamically, in an on-demand fashion. By defining standardized protocols for discovering, accessing, monitoring, and managing remote computers, storage systems, networks, and other resources. To ensure that once a resource is accessed, it fulfils user expectations for quality of service (QoS) and to provide execution guarantees. Grid provide access to many resources with diverse software configurations, a user’s application will typically run only in a specific, customized software environment. Variations in operating systems, middleware versions, library environments, and file system layouts all pose barriers to application portability. Thus, in practice, users are often unable to leverage the available resources without tedious debugging and porting efforts that drain time and energy from their primary objectives, thus compromising their “quality of life” in interactions with Grid software an application can abstract the properties of an environment it requires for execution in terms of memory size, the number of processors, or library. A resource can define its offered capabilities in similar terms. Such environment abstractions can be implemented by using a variety of sandboxing technologies and can be mapped onto resources, offering the required degree of isolation, fine-grained enforcement, and configuration. The virtual workspace (VW) abstraction to describe such environments. It describes how a workspace deployed on a physical resource can provide a deployment capability for setting up virtual machines, matchmaking, with negotiation and advance reservation protocols [5], can be used to create complex workspaces.

INDEX TERMS: Virtual Workspace, Grid Technology, Protocols, Remote Systems, Quality of service, Middleware.

1. Introduction

A virtual environment is an abstraction of an execution environment that can be made dynamically available to authorized clients by using well-defined protocols. The abstraction captures the resource quota assigned to the execution environment as well as its software configuration. Different workspace implementations provide different workspace management capabilities.

1.1 Workspaces as Site-Provided Installations

Nodes on site installations, often configured to support the needs of specific communities such as Open Science Grid or TeraGrid, can provide workspaces to Grid clients. One way of providing workspaces relevant to a specific community is to obtain a priori agreement on required configurations, and then simply deploy those configurations, advertise them, and provide access. This approach is often practiced today. A more flexible way is to allow for automated boot of physical nodes based on a configuration description and boot images.

The final step in making a site-provided installation available as a workspace is providing access to Grid clients. Such access is typically provided by the use of dynamic accounts: accounts generated on the fly or assigned from a pre-generated pool. In addition to workspace creation, this implementation provides a flexible interface for access management and policy inspection. The account cleaning process is configurable by the site administrator and, for additional security, includes an optional quarantine. Typically resources are made available in a relatively coarse-grained manner allocating the number of nodes or amount of available disk space but not enforcing fine-grained quotas, such as percentage of CPUs between users of a specific resource.

While providing access to site-configured workspaces is a fast and widely accepted solution it lacks flexibility in that it offers little choice in shaping the workspace’s configuration or the resource allocation associated with it.

1.2 Virtual Cluster Workspaces

Workspaces implemented via any of the methods just described can be grouped to create virtual clusters of various topologies. A virtual cluster workspace can be constructed via, an existing cluster with tools for dynamically enabling access, or a cluster of virtual machines. When using a virtual machine implementation, a virtual cluster workspace is implemented in terms of multiple VM images that may represent specialized nodes such as worker or head nodes.

2. Virtual Workspace Concept

A workspace description should contain sufficient information for a deployment service to create the environment represented by this workspace. This information is of two kinds: (1) description of packages or other data that need to be obtained from potentially external sources and put together (such as a software installation package or a VM image), and (2) deployment logistics information, which needs to be interpreted and configured at deployment time .

The quantity of information that must downloaded and the amount of deployment-time configuration will depend on both workspace implementation and the deployment service implementation. We adopt an approach that strikes a balance between definition flexibility and deployment-time configurability and speed. We describe a workspace using the XML schema depicted in block form in Figure 1.

The description associates a workspace name with its definition and deployment logistics information. The workspace name is a Uniform Resource Identifier (URI) that can be resolved to obtain more information about the workspace, such as its provenance, creation and modification times, or detailed software catalogue. While irrelevant to deployment, this information is valuable to a workspace client.

We represent a workspace as a collection of modules that can be combined to define the workspace’s content. These modules may include a variety of components such as a system module, a community specific configuration layer, or an application module. These different components can be obtained at different times and from different sources, thus optimizing VM image transfer. Thus, the definition section of the workspace description contains a definition of workspace modules together with information describing how they should be obtained and put together, as well as deployment information describing how the workspace should be configured on deployment. In order to enable verification prior to deployment, the definition section additionally specifies prerequisites for workspace deployment.

The deployment service must be able to resolve how to acquire the partitions, verify their integrity, and instantiate the VM such that the proper image is loaded by the VM at the expected device. Thus, for each individual module we specify a module name, the location at which the module can be obtained, the device binding to which it should be bound, and modes of operation (permissions). Like the workspace metadata, a partition name is a URI that can be used in conjunction with other services to obtain more information about a specific partition including dependencies on other partitions.

A partition location can be resolved to locate and transfer an actual image partition. We are currently creating an additional attestation element to describe who developed a partition and attested to its content. To complete VM instantiation, we also need to describe deployment information on how to provide networking and (potentially) additional storage. This content is contained in the deployment section of the workspace. To reflect that fact that a VM can have an arbitrary number of network interfaces (NICs) that are mapped to physical hardware in different ways, networking is described as a collection of NIC elements. For each NIC, we describe naming (the method used to obtain an IP address), network binding describing how VM’s network interfaces are bridged and managed outside the VM, and the IP address.

The network binding can be bridged directly to a physical NIC, bridged to a VPN, configured behind a NAT of one of the host machine’s IP addresses, or configured to use an isolated LAN.

Atomic workspaces, describing one execution environment, can be combined to form aggregate workspaces such as virtual clusters. An aggregate workspace is defined to contain sets of homogeneous atomic workspaces. This approach allows us to define heterogeneous a head node and worker nodes.

Figure 1: Graphical representation of the workspace schema. Plus signs denote “one or more elements”.

All information about a cluster workspace is derived from the metadata of the atomic workspaces describing those nodes. While workspace metadata describes where VM image parts can be obtained, it does not include them. Images as well as workspace descriptions can be put together by VO deployment teams supporting specific groups of applications. Such workspaces can then be shared, copied, and incrementally refined, allowing users to further customize VWs to suit a particular set of needs. VMPlant implements such a service, which however combines the process of VM configuration with its deployment. In this architecture those roles are split: once put together, a workspace description may be deployed many times, each time potentially with a different resource allocation.

3. Creating, Deploying, and Managing Virtual Workspaces

We use the term Workspace Service to denote the entity responsible for deploying a workspace and associating it with a specific resource allocation. Figure 2 illustrates these services and their function. To obtain a workspace description, a client first works with either workspace configuration services to create a new workspace, or selects from existing workspaces using an information service that associates workspace images with information about those images and the deployment capability (services) they provide. Workspace deployment comprises two phases: obtaining the workspace data required for deployment and using that data to deploy the workspace onto a requested set of resources. Implementing the first phase may require orchestrating workspace data transfer from remote sources to the site where the workspace will be deployed. Efficiently scheduling such transfers can require global knowledge and coordination. In the second phase, the workspace data is available at the selected site and the workspace can now be deployed using this site’s workspace service. In order to do this, the workspace service must be able to interpret the workspace description and be in control of resources that provide the deployment capability for this kind of workspace (e.g., a hypervisor for virtual machines). At deployment, a workspace is associated with a resource allocation requested by the client. This resource allocation, as well as other deployment-specific properties of the workspace, can be managed throughout its deployment. All workspace service operations are subject to authorization; authorization policy may be expressed in terms of both the requesting client and the workspace itself. Once the workspace is deployed, an authorized client can interact with services within the workspace. Note that at this point, the client is authorized by services executing within the workspace. By the act of deploying the workspace and associating it with a resource allocation, the workspace service effectively delegates to the workspace the use of this allocation.

Figure 2: Creating and deploying workspaces.

Work on other services is pursued elsewhere; here we focus on the Workspace Service. We define Workspace Service protocols based on the Web Services Resource Framework (WSRF), which provides standard methods for the creation and management of manageable state descriptors called “WS resources.” A Workspace Factory Service uses a “create” operation to create a WS resource representing the new workspace. Associated with each WS Resource are a limited lifetime and other resource properties that can be inspected, queried, and managed in standard ways, and that can be used in conjunction with WS-Notifications to provide updates on change. A resource can be destroyed either explicitly or by allowing its lifetime to expire. The Workspace Factory “create” operation takes as input a workspace description and a description of a resource allocation to be applied to the workspace on start up. The resource allocation request contains a request for association with a resource allocation for a specified length of time. The resource allocation is specified as constrained values that are bound to specific values when the request is accepted. The workspace to start may take a relatively long time. In addition to the operations used to manage the WS resource, we define operations that allow a client to start a workspace and to shut down a started workspace. Workspace shutdown takes an argument that allows the client to express properties of the shutdown, such as pause, pause and serialize, hard-reboot, and trash (shut down and destroy images). A workspace may be started and shut down many times throughout the lifetime of the WS resource associated with it. A client may use the resource properties to adjust the resource allocation given to a workspace using the WSRF SetResourceProperties operation.

4. Putting It All Together: Workspaces, Agreements, and Brokers

While virtual machines provide a compelling solution for environment deployment, their own deployment, as well as its scope, relies on the presence of compatible hypervisors on a resource. In this section, we discuss how different implementations of workspaces can be put together to implement the full stack of interactions required for workspace deployment. A workspace is associated with a deployment capability. As the figure below illustrates such capabilities can support the deployment of jobs or other workspaces. The Workspace Service, implementing workspace deployment, can operate at each layer; however, at each layer, workspace deployment is associated with different implementations and ownership.

Figure 3: Environment layers: A and C are hypervisor workspaces, each supporting the deployment of different types of virtual machines, which in turn provide job execution capabilities. Workspace B provides job execution capability.

Virtual machines, whose deployment and shutdown can easily be controlled by a site without impairing the availability of its resources, can be configured by communities wishing to support specific applications. While today a site typically simply advertises the supported deployment capability, such advertisements are static and do not allow much flexibility in the support of deployment capabilities. If, in practice, one dominant capability is required by the site users ( hypervisor ) this model is sufficient. However, systems such as COD offer a more flexible model that implements site-specific workspace services that allow an authorized client to request the deployment of a workspace from a limited set. Providing standardized interfaces to such services would enable a client to flexibly negotiate required workspaces at different sites.

These interfaces are likely to be based on emerging standards such as WS-Agreement [5]. Figure 3 shows how the full workspace deployment could be negotiated using WS-Agreement. A broker negotiates an agreement with a site for the availability of a set of resources and obtains a resource allocation agreement. Workspace deployment requests, defining a deployment capability and a resource allocation request, can now be made against that resource allocation agreement. If the request is successful, a workspace deployment is bound to the available resource allocation, and the hypervisor configuration is deployed on the requested resources.

Figure 4: Negotiating workspaces in the Grid.

It should be noted that it is the deployment capability that is advertised by a site. The power of using virtual machines relies on the fact that maintain configuration images required by many different communities, in practice only a few images can be maintained. However, maintaining a few generic hypervisor images gives the sites a platform that can be used to deploy a large variety of environments.

5. Summary and Future Work

Virtual machines, enable many scenarios that are hard to achieve with current tools. We expect that providing reliable quality of service enforcement will lead to more widespread use of agreement-based protocols and commercial interactions in resource use and contributions. The ability to deploy remote workspaces reliably will provide much needed “quality of life” for Grid users, who will be able to use more resources with greater confidence. Workspaces also make it easier for resource owners to contribute resources to the Grid and to manage virtual organizations. Workspaces can be used for management at different layers. Virtual organizations can manage workspaces for their applications while still giving a site coarse-grained control over workspace images via attestation.

Much research is still required to realize this vision. In future work, we plan to further refine and experiment with virtual workspaces and to work on ensuring their security, developing networking infrastructure, and devising methods that leverage the migration capability and other aspects.

6. References

1. Foster, I., C. Kesselman, J. Nick, and S. Tuecke, The Physiology of the Grid: An Open

Grid Services Architecture for Distributed Systems Integration. 2002: Open Grid Service Infrastructure WG, Global Grid Forum.

2. Foster, I., C. Kesselman, and S. Tuecke, The Anatomy of the Grid: Enabling Scalable

Virtual Organizations. International Journal of Supercomputer Applications, 2001. 15(3): p. 200-222.

3. Goldberg, R., Survey of Virtual Machine Research. IEEE Computer, 1974. 7(6): p. 34-45.

4. Keahey, K., I. Foster, T. Freeman, X. Zhang, and D. Galron, Virtual Workspaces in the Grid. anl/mcs-p1231-0205, 2005.

5. Andrieux, A., K. Czajkowski, A. Dan, K. Keahey, H. Ludwig, J. Pruyne, J. Rofrano, S.Tuecke, and M. Xu, Web Services Agreement Specification (WS-Agreement) Draft 20. 2004: https://forge.gridforum.org /projects/graap-wg/.

RECENT TRENDS IN IT :: NANO ROBOTICS

2012-06-26T02:30:00.000-07:00

RECENT TRENDS IN IT :: NANO ROBOTICS

ABSTRACT

· Nanorobots are nanodevices that will be used for the purpose of maintaining and protecting the human body against pathogens.

There is no technology for the treatment of AIDS. Some of the drugs of specific composition are given to the patients depending on the intensity of the disease. The drugs using nowadays are able to increase the lifetime to a few years only. To make the treatment more specific, we use the nanodevices that use nanosensors to sense the AIDS infected WBC’s. In this we are using nanorobots to get back the HIV infected WBC’s. By doing so constant levels of WBC’s are maintained in the blood stream.

In India more than 50 lakhs of people are infected by this dreaded disease and it constitutes 10% of the total infected. We are doing research on this paper and we hope that this theoretical approach can be made practical in the near future, so that the killer disease AIDS could also be made in control on the hands of Human with the emerging new technology like NANOTECHONOLOGY which has a Bi o-medical Application.

INTRODUCTION

Nano is one billionth of one. Now we have the so NANOTECHNOLOGY called microprocessors and microarray technology that would reach the nano level within a few decades, we suppose. Some call this technology to be nanotechnology and some others name it the molecular nanotechnology, to be specific.

REASONS FOR APPLYING NANOTECH TO BIOLOGICAL SYSTEMS

Most animal cells are 10,000 to 20,000 nanometers in diameter. This means that nanoscale devices (having at least one dimension less than 100 nanometers) can enter cells and the organelles inside them to interact with DNA and proteins. Tools developed through nanotechnology may be able to detect disease in a very small amount of cells or tissue. They may also be able to enter and monitor cells within a living body. Miniaturization will allow the tools for many different tests to be situated together on the same small device. This means that nanotechnology could make it possible to run many diagnostic tests simultaneously with more sensitivity. In general, nanotechnology may offer a faster and more efficient means for us to do much of what we do now

NANOMEDICINE

The emerging field of nanorobotics is aimed at overcoming the shortcomings present in the traditional way of treatment of patients. Our bodies are filled with intricate, active molecular structures. When those structures are damaged, health suffers. Modern medicine can affect the work of the body in many ways, but from a molecular viewpoint it remains crude. Molecular manufacturing can construct a range of medical instruments and devices with greater abilities. The human body can be seen as a workyard, construction site and battleground form molecular machines. It works remarkably well; using systems so complex that medical science still doesn’t understand many of them.

BIOMEDICAL APPILICATIONS OF NANOROBOTS

The enormous potential in the biomedical capabilities of nanorobots and the imprecision and side effects of medical treatments today make nanorobots very desirable. But today, in this revolutionary era we propose for nanomedical robots, since they will have no difficulty in identifying the target site cells even at the very early stages which cannot be done in the traditional treatment and will ultimately be able to track them down and destroy them wherever they may be growing. By having these Robots, we can refine the treatment of diseases by using biomedical, nanotechnological engineering.

Nanorobot designed to perform cell surgery

WHAT IS A MEDICINAL NANOROBOT ?

Nanorobots are theoretical microscopic devices measured on the scale of nanometers (1 nm equals one millionth of a millimeter). When fully realized from the hypothetical stage, they would work at the atomic, molecular and cellular level to perform tasks in both the medical and industrial fields that have therefore been the stuff of science fiction .Nanomedicine’s nanorobots are so tiny that they can easily traverse the human body. Scientists report the exterior of a nanorobot will likely be constructed of carbon atoms in a diamondoid structure because of its inert properties and strength. Super-smooth surfaces will lessen the likelihood of triggering the body’s immune system, allowing the nanorobots to go about their business unimpeded. Glucose or natural body sugars and oxygen might be a source for propulsion and the nanorobot will have other biochemical or molecular parts depending on its task.

Nanorobot in Nano scale

According to current theories, nanorobots will possess at least rudimentary two-way communication; will respond to acoustic signals; and will be able to receive power or even re-programming instructions from an external source via sound waves. A network of special stationary nanorobots might be strategically positioned throughout the body, logging each active nanorobot as it passes, then reporting those results, allowing an interface to keep track of all of the devices in the body.
A doctor could not only monitor a patient’s progress but change the instructions of the nanorobots in vivo to progress to another stage of healing. When the task is completed, the nanorobots would be flushed from the body.

Nanorobot performing operations on blood cells

Nanorobotic phagocytes called microbivores could patrol the bloodstream, seeking out and digesting unwanted pathogens including bacteria, viruses or fungi. Each nanorobot could completely destroy one pathogen in just 30 seconds - about 100 times faster than natural leukocytes or macrophages - releasing a harmless effluent of amino acids, mononucleotides, fatty acids and sugars. No matter that a bacterium has acquired multiple drug resistance to antibiotics or to any other traditional treatment. The microbivore will eat it anyway, achieving complete clearance of even the most severe septicemic infections in minutes to hours, as compared to weeks or even months for antibiotic-assisted natural phagocytic defenses, without increasing the risk of sepsis or septic shock. Related nanorobots could be programmed to recognize and digest the cancer cells and to clear circulatory obstructions within a minute in order to rescue stroke patients from ischemic damage.

More sophisticated medical nanorobots will be able to intervene at the cellular level, performing surgery within cells. Physician-controlled nanorobots could extract existing chromosomes from a diseased cell and insert newly manufactured ones in their place, a process called chromosome replacement therapy. This would allow a permanent cure of any pre-existing genetic disease, and permit cancerous cells to be reprogrammed to a healthy state.

IMPLEMENTATION

ANTI - HIV USING NANOTECHNOLOGY

AIDS

The virus responsible for the condition known as AIDS (Acquired Immunodeficiency Syndrome), is named HIV (Human Immunodeficiency Virus). AIDS is the condition whereby the body's specific defense system against all infectious agents no longer functions properly. There is a focused loss over time of immune cell function, which allows intrusion by several different infectious agents, the result of which is loss of the ability of the body to fight infection and the subsequent acquisition of diseases such as pneumonia.
The immune system is a system within all vertebrates , which in general terms, is comprised of two important cell types namely B-cell and T-cell. B-cell is responsible for the production of antibodies (proteins which can bind to specific molecular shapes), and the T-cell (two types) is responsible either for helping the B-cell to make antibodies, or for the killing of damaged or "different" cells (all foreign cells except bacteria) within the body. The two main types of T-cells are the "helper-cell and the cytotoxic T-cell. The T-helper population is further divided into those which help B-cells (Th2) and those which help cytotoxic T-cells (Th1). Therefore, in order for a B-cell to do its job requires the biochemical help of Th2 helper T-cells; and, for a cytotoxic T-cell to be able to eliminate a damaged cell requires the biochemical help of a Th1 helper T-cell.

IMMUNESYSTEM

Whenever any foreign substance or agent enters our body, the immune system is activated. Both B- and T-cell members respond to the threat, which eventually results in the elimination of the substance or agent from our bodies. If the agent is one which goes inside one of our cells and remains there most of the time (intracellular pathogens like viruses or certain bacteria which require the inside of one of our cells in order to live), the "best" response is the activation of cytotoxic T-cells (circulate in the bloodstream and lymph), which eliminate the agent through killing of the cell which contains the agent (agent is otherwise "hidden"). Both of these kinds of responses (B-cell or cytotoxic T-cell) of course require specific helper T-cell biochemical information as described above. Usually, both B-cell and cytotoxic T-cell responses occur against intracellular agents which provides a two-pronged attack. Normally, these actions are wonderfully protective of us. The effect of HIV on the immune system is the result of a gradual (usually) elimination of the Th1 and Th2 helper T-cell sub- populations.

OPERATION OF HIV

How HIV specifically affects the Immune System?
Remember about the proteins, which are part of the envelope of HIV?
Well, one of these proteins, named gp 120, (a sugar-containing protein called a glycoprotein, of approximately (120,000 molecular weight), "recognizes" a protein on helper T-cells named CD4, and physically associates with it. The CD4 [Cluster of Differentiation Antigen No. 4] protein is a normal part of a helper (both Th1 and Th2) T-cell's membrane.

1. Method of infection of HIV

Thus, CD4 is a specific receptor for HIV. This virus however, can also infect other cells which include macrophages and certain other kinds of cells which can engulf substances through a process known as phagocytosis. As a consequence of the interaction with CD4 on helper T-cells, HIV specifically infects the very cells necessary to activate both B-cell and cytotoxic T-cell immune responses. Without helper T-cells, the body cannot make antibodies properly, nor can infected cells containing HIV (an intracellular pathogen) be properly eliminated. Consequently, the virus can multiply, kill the helper T-cell in which it lives, infect adjacent helper T-cells, repeat the cycle and on, until eventually there is a substantial loss of helper T-cells.

The fight between the virus and the immune system for supremacy is continuous. Our body responds to this onslaught through production of more T-cells, some of which mature to become helper T-cells. The virus eventually infects these targets and eliminates them, too. More T-cells are produced, these too become infected and are killed by the virus. This fight may continue for up to ten years before the body eventually succumbs, apparently because of the inability to any-longer produce T-cells. This loss of helper T-cells finally results in the complete inability of our body to ward-off even the weakest of organisms (all kinds of bacteria and viruses other than HIV) which are normally not ever a problem to us. This acquired condition of immunodeficiency is called, AIDS.

1. Structure of AIDS virus

METHODOLOGY

AIDS by itself is not a killer disease. The cause of AIDS is the HIV virus that is capable of destroying the immune system. Thereby the host system is vulnerable to small diseases which will turn into a fatal one but actually it is not a fatal disease. The HIV virus attack the WBC’s by converting them into the HIV. Thereby all the WBC’s are converted into HIV, so the immune system will fail. This is the reason for the death of the patient. Our idea is to convert the AIDS affected WBC’s back into the original form of the WBC by using a Nanorobot, thereby the patient is made to have a constant amount of immune system. Nanorobot performs the inverse process of the HIV.

CONVERSION RATE

The HIV convert the WBC in a faster manner .So the conversion by the A-HIV Nanorobot should also be very much faster than that of the HIV, so that a constant level of WBC’s are maintained in the blood stream. Because of this ,an AIDS patient can defend himself from various diseases .The conversion rate should be at least five times greater than that of the HIV conversion rate.

BASIC EQUATION

The basic equation for the conversion of the HIV infected WBC’s back to its original form is given below. The host system is the WBC and is converted by the HIV into an infected WBC. This is the reason for AIDS.

CREATION OF NANO DEVICES

The creation of the nano devices can be done using any of the two techniques that are available. They are

· Top-down approach

· Bottom-up approach

CHALLENGES FACED BY NANOROBOTS

While designing nonorobots in nanoscale dimensions there should be a better understanding of how matter behaves on this small scale. Matter behaves differently on the nanoscale than it does at larger levels. So the behavior of the nanorobots must be taken care so that the do not affect us both inside and outside the body.

Other challenges apply specifically to the use of nanostructures within biological systems. Nanostructures can be so small that the body may clear them too rapidly for them to be effective in detection or imaging. Larger nanoparticles may accumulate in vital organs, creating a toxicity problem. So we need to consider these factors as they anticipate how nanostructures will behave in the human body and attempt to create devices the body will accept.

DESIGN OF NANOROBOTS

The nanorobots that we describe here will be floating freely inside the body exploring and detect the HIV virus. So, while designing such a nanorobot for AIDS treatment, the main factors that are to be considered are given below.

TECHNIQUE USED

We use the bottom-up approach, which involves assembling structures atom-by-atom or molecule-by-molecule which will be useful in manufacturing devices used in medicine.

SIZE

Nanorobots will typically be 0.5 to 3 microns large with 1-100 nm parts. Three microns is the upper limit of any nanorobot because nanorobots of larger size will block capillary flow.

STRUCTURE

The nanorobot’s structure will have two spaces that are

Interior

It will be a closed, vacuum environment into which liquids from the outside cannot normally enter unless it is needed for chemical analysis.

Exterior

It will be subjected to various chemical liquids in our bodies.

CHEMICAL ELEMENTS

Carbon will likely be the principal element comprising the bulk of a medical nanorobot, probably in the form of diamond or diamondoid or fullerene nanocomposites largely because of the tremendous strength and chemical inertness of diamond. Many other light elements such as hydrogen, sulfur, oxygen, nitrogen, fluorine, silicon, etc. may also be used.

ACQUIRING POWER

It could metabolize local glucose and oxygen for energy. Another possibility is externally supplied acoustic power, which is probably most appropriate in a clinical setting. There are literally dozens of useful power sources that are potentially available in the human body.

COMMUNICATON

Having nanorobots inside the body it is very essential to know the actions done by it. There are many different ways to do this. One of the simplest ways to send broadcast-type messages into the body, to be received by nanorobots, is acoustic messaging. A device similar to an ultrasound probe would encode messages on acoustic carrier waves at frequencies between 1-10 MHz.

TRACKING

A navigational network may be installed in the body, with stationkeeping navigational elements providing high positional accuracy to all passing nanorobots that interrogate them, wanting to know their location. Physical positions can be reported continuously using an in vivo communications network.

STRUCTURE OF NANOROBOT

The nanorobot consists of three main parts like the DNA sensor,CPU,RNA converter and the power system. The purpose of DNA sensor is to identify the HIV infected cell. The RNA converter is used to change the RNA of the HIV. The CPU controls all the activities .The power system provides the necessary energy for the working of the nanorobot.

1.

COMPONENTS OF NANOROBOT

DNA SENSORS

The DNA sensor is an cantilever type. In one arm the actual sample is placed and in the second arm the sample from the WBC is placed. Even if the samples differ by a single base ,it can be identified. The structure is given below.

Carbon nanotube network field-effect transistors (NTNFETs)that function as selective detectors of DNA immobilization andhybridization. NTNFETs with immobilized synthetic oligonucleotideshave been shown to specifically recognize target DNA sequences,including H63D single-nucleotide polymorphism (SNP) discriminationin the HFE gene, responsible for hereditary hemochromatosis.The electronic responses of NTNFETs upon single-stranded DNAimmobilization and subsequent DNA hybridization events wereconfirmed by using fluorescence-labeled oligonucleotides andthen were further explored for label-free DNA detection at picomolarto micromolar concentrations

POWER SYSTEM

The nanorobot uses the glucose molecules present in the human body as the power source. The conversion of this glucose molecule into the energy is accomplished by the energy converter, which is an important part of the nanorobot.

REQIREMENTS OF THE NANOROBOT

It should e very small so that the blood capillary flow is not affected.
It should not be affected by the WBC.
It should be capable of sensing the HIV infected WBC only and its action is restricted to the infected WBC only.
It should make its operations in the RNA to convert back to the original DNA of the WBC by suitably changing the bases like the adenine, guanine.
It should convert the infected WBC into the original WBC in a very faster manner.
It should be made of cheaper rates, so that the patient can afford it easily.

OPERATION

The designed anti-HIV nanorobots are injected into the blood stream. These nanorobots continues the process of conversion in the bone marrow, blood and in the thymus glands where the concentration the WBC‘s are more. This process takes pace till the normal death of the patient.

CONCLUSION:

The paper is just a theoretical justification. But the recent advancement in the field of nanotechnology gives the hope of the effective use of this technology in medical field. This paper starts by giving an introduction to nanorobots and its importance as recognized by various other technocrats. This is the beginning of nanoera and we could expect further improvements such as a medicine to AIDS using nanotechnology .

RATBOTS USING RATS AS ROBOTS

2012-06-26T01:32:00.000-07:00

RATBOTS

USING RATS AS ROBOTS

Abstract :

“Robot" as an "apparently human automation, intelligent but impersonal machine..."

A ratbot or roborat is a rat controlled through implants in its brain.

            Guided rats controlled through implants in their brains could one day be used to search for landmines or buried victims of earthquakes, scientists say.

            An extraordinary experiment has seen researchers steering five rodents - so-called rat bots - through an obstacle course by remote control.

            Writing in the journal Nature, the scientists say the ratbots could reach places inaccessible to humans or machines.

"One can think of the guided rat as a very good robot platform capable of traversing terrain that modern robots are unable to do," Dr Talwar said

The rodents in the first experiment wore a small electronics backpack that linked to electrodes in their brains. They received radio commands from a laptop that would stimulate sensations in their whiskers and reward/pleasure receptors to manipulate them into following pre-programmed routes. Some researchers propose using them to search for landmines or buried victims of earthquakes, as they can much more efficiently scout such areas than human rescuers or existing robots.

The rats also quickly learnt to associate the stimulation of their brains' reward centres with simply walking forwards, even if this involved climbing or descending ladders or steps, or moving into the centre of a brightly lit room - something that most rats would avoid.

INTRODUCTION

Rat - common name for any large member of a family of rodents, with dull - colored, coarse fur; long tails; large ears; and a pointed snout. Rats have extremely powerful teeth, with which they often gnaw through wooden planks to get at stores of food, and they have even been known to bite holes in lead pipes. They are usually nocturnal and live in human habitations, in forests, in deserts, and on seagoing ships. They are extremely prolific, breeding 1 to 13 times a year and producing 1 to 22 young in a litter. Most species of rats are herbivorous, but some are omnivorous. Rats have an average lifespan of eight months to one year in the wild and two to three years in captivity.

· Animals have often been used by humans in combat and in search and rescue, but not under direct computer-to-brain electronic control.

· The advent of surgically altered roborats marks the crossing new boundary in the mechanization, and potential militarization, of nature.

· This ratbot technology isn’t nanotechnology yet, and it is not new, as the principle of “MIND CONTROL” through implantable devices is the same

THE FIRST ROBORAT

"Robo-rat" controlled by brain electrodes

The age of the living robot is upon us. And all it takes to turn a living rat into a radio-controlled automaton is three electrodes carefully placed in the animal's brain. Simply pressing keys on a computer 500 meters away will then steer the animal over an obstacle course, making it twist, turn and even jump on demand.

The researchers responsible for the "Robo Rat" claim their work will give neuroscientists a better understanding of how mammals learn to navigate. They say it will help pinpoint biochemical changes in the brain, and which brain regions are involved in processing different behaviours. They even suggest that such rats could be used to help clear minefields.

But beyond this, lead researcher Sanjiv Talwar of the State University of New York in New York City is uncertain what benefits will emerge from the experiments. "It's difficult to predict what other studies this could be useful for right now," he told New Scientist. "There's going to have to be a wide debate to see whether this is acceptable or not."

The idea of placing living creatures under direct human command is certainly raising concerns over the animals' welfare. "It's appalling, and yet another example of how the human species instrumentalises other species," says Gill Langley of the Dr Hadwen Trust based in Hitchin, Hertfordshire, which funds alternatives to animal-based research.

Brain electrodes

Animal experiments such as drug trials are usually justified using the utilitarian argument. For a procedure to be acceptable, any suffering caused to an animal is supposed to be outweighed by an obvious benefit to people.

"There are some ethical issues here which I can't deny," Talwar says. But he points out that the experiments stuck to guidelines laid down by the US National Institutes of Health, and he insists that the animal cannot be dubbed a "remote-controlled rat". The rat was not forced to do anything, he says, as the technique works by stimulating the reward centre of its brain.

The researchers implanted one of the electrodes into the medial forebrain bundle (MFB), the part of the brain responsible for sensing reward. They placed the other two in parts of the somatosensory cortical area that receive stimulation from the left and right whiskers. Finally, a radio receiver tucked inside a rat-sized backpack was plugged into an interface in the rat's skull.

The rats were trained to learn that they would be rewarded with continuous zaps to the MFB when they moved forwards, or when they turned according to an appropriate stimulation of the left or right whisker.

Carrot and stick

Talwar likens the control over the rat to the way a donkey can be steered by a carrot on a stick. Though driven by a desire to be rewarded, the donkey remains in control of its movements. Using the same principle, the rat can be trained to do things it would not normally do, such as walking into brightly lit open spaces or jumping off a ledge.

But Gary Francione, an expert in animal welfare law at Rutgers University School of Law, says: "The animal is no longer functioning as an animal," as the rat is operating under someone's control.

And the issue goes beyond whether or not the stimulations are compelling or rewarding the rat to act. "There's got to be a level of discomfort in implanting these electrodes," he says, which may be difficult to justify.

Talwar says the animals probably could not be persuaded to risk their lives in any way. Even so, he admits he cannot rule out coercion completely. For instance, the rats were never trained to jump off a ledge, but would do when commanded to go forward.

In this case the stimulation appeared to act like a prod rather than a reward. Previous research has shown that if rats are stimulated electrically in this reward centre every time they press a lever, they may continue doing so until they die.

Fast forward

Talwar has so far wired up five rats. He suggests that other electrodes could be added to give additional commands, like faster, or up and down. In theory, the technique should work with any animal that has an MFB, including most mammals and birds, although it's likely that higher animals could learn to ignore the commands.

Talwar suggests wired animals would be ideal for search and rescue operations, as they could be directed through rubble to look for survivors and would be easier to navigate than mechanical robots.

But Langley is concerned that other scientists will repeat the experiments on other animals, despite the ethical issues this raises. "The US Federal Animal Welfare Act doesn't cover rodents or birds," she points out, so researchers would not need a license or ethical approval.

Journal reference: Nature (vol 417, p 37)

Duncan Graham-Rowe

INTO THE TOPIC

· Two electrodes lead to the parts of the rats' brains, which normally detect an obstacle against their whiskers. A third plunges into an area of the brain identified as far back as the 1950s as providing the rat with a feeling of pleasure when stimulated this area of stimulation is called Medial Forebrain Bundle (MFB)

· Once trained they would move instantaneously and accurately as directed, for up to an hour at a time. The rats could be steered up ladders, along narrow ledges and down ramps, up trees, and into collapsed piles of concrete rubble.

STEP WISE PROCEDURE OF HOW RATBOTS ARE BUILT

· Step-1

After anesthesia being given, the mouth of the rat is first cut in order to go through the incision towards Brain.

· Step-2

Now the incision continues towards to the head position to reach the brain

· Step-3

The Three electrodes used for stimulation are placed .

· Step-4

A Back Pack with batteries, an antenna, a receiver and a camera is placed to rat as shown beside

· Step-5

Finally the rat is molded into Ratbot and the only thing left with it is, it should be trained

HOW RATBOTS LOOK LIKE…

The remote control rats look like school children, wearing small backpacks that house microprocessor-based remote-controlled stimulators. Wires connect the backpack to tiny probes that have been placed into areas of the rat’s brain that are responsible for reward and areas that process signals from their whiskers. Manipulating these two areas of the brain controls the rats.

WORKING (OR) OPERATION OF RATBOT

SCIENTISTS OPINIONS (ABOUT RATBOT)

· It could save a lot of lives. It's not all bad for the rats because they feel pleasure when they go the right way

-------Sophie

· Rats are small and can fit into places where we can’t. If it helps save lives then we should implement it.

-------Ashley

APPLICATIONS

Ø Giant Rats Trained To Sniff Out Land Mines

Ø Roborat Could Help Find Earthquake Victims

Ø Used to find explosives.

THE FUTURE

This discovery grew out of ongoing research into the development of thought-controlled prosthetic devices, roboroach, moving a cursor using brain signal etc.,

EVOLUTION OF THE IDEA

The work on guided rats was an offshoot of earlier research which showed that animals wired up to a processor could command a robotic arm by thought alone, a development which could potentially empower paralyzed humans

FUTURE DEVELOPMENTS

In one sense, the news last week that scientists have created a "roborat" represents an ingenious technical breakthrough. Engineers have tried for years--without success--to build robots smart enough to cross even a railroad track. Now, by combining off-the-shelf technology with a creature whose maneuvering skills have been honed by millions of years of evolution, physiologists at the State University of New York Downstate Medical Center in Brooklyn have created remotely piloted rodents that navigate complex terrain at the will of controllers who are more than 500 yards away. Wearing tiny backpacks equipped with radio transmitters and miniature TV cameras, the rats could someday be sent into a collapsed building to find survivors, say the scientists, or into a minefield to sniff out danger or off on a spy mission.

But look a little deeper, and the accomplishment is both less and more than meets the eye. It's less in part because the technology involved is so simple. Trainers have known for centuries that you can teach animals to perform all sorts of behaviors with a system of rewards or punishments. Neurophysiologists have known for decades that instead of an external reward like food, you can send electric impulses directly into the brain's pleasure center.

As they reported last week in Nature, Sanjiv Talwar and his colleagues did just that, tickling the rats' brains via radio transmitter when the rodents moved in a direction the researchers wanted. But although Talwar's team got the rats to do things they ordinarily wouldn't--climb trees, go out in bright light, ignore the scents of food and females--it took a controller at the helm to make this happen.

So although the rats may sound like cyborgs, they are really just rodents that follow instructions. And although they fit into tiny spaces and are more or less expendable, they are less useful in many ways than bloodhounds or bomb-sniffing dogs--or even primitive robots, which will roll mindlessly into fires, under water or into the glow of a nuclear-power-plant meltdown.

What's truly novel about this project is the way the rat controllers issue their instructions. By tapping a keyboard, they send signals via radio waves to electrodes implanted in the animal's brain: a mild jolt to neurons that sense the right whiskers means "turn right"; a zap to the left-whisker neurons means "go left." The surprise was how easy this was to do. Neurophysiologists have long dreamed of building artificial limbs with tactile feedback that would be sufficiently sensitive to tell a user when a hand is grasping a barbell tightly enough to keep it from falling or a baby chick loosely enough to keep from crushing it.

That's what Talwar and his group were trying to understand. "We wanted to determine how well rats understand incoming signals," he explains. "When we stimulated a region of the whiskers, they 'felt' a touch." Someday, says Mandayam Srinivasan, director of the M.I.T. Touch Lab, who helped show two years ago that monkeys could control robots by thought alone, "you could build a neural chip for paralyzed people, similar to a cochlear implant for deaf people, that uses brain signals to control prostheses.

Ethical problems

"It is a hard problem simply trying to make a robot move properly over unpredictable terrain. It would be a simple matter to train rescue rats to recognise and home in on the smell of a human trapped under rubble."

Dr Talwar acknowledged there might be ethical objections to such ideas, even if they could save human lives.

"Our animals were completely happy and treated well and in no sense was there any cruelty involved," he says.

"Nonetheless, the idea is sort of creepy. I do not know what the answer is to that."

CONCLUSION

New inventions in science always have ethics as a shadow.

So what ever may be the ethics, the rat loves to become a RATBOT and helps to save human life.

REFERENCES

www.wireheading.com

www.rense.com

www.infowars.com

MOBICHARTS: A Notation to Specify Mobile Computing Applications

2012-06-26T00:37:00.000-07:00

MOBICHARTS: A Notation to Specify Mobile Computing Applications

Abstract

A standard notation, that unambiguously expresses different aspects of a system, is important to the process of software development. The expressiveness of a standard notation helps analysts and developers to describe a computing scenario or to formulate software architecture and then to communicate these decisions unambiguously to other team members. Much attention is already given to the software development methodologies and architectural descriptions. Specifically, Statecharts and state transition diagrams have been used to show the state space of a system, the events that cause state transitions and the actions that result from a state change. The paradigm shift to object-oriented programming has changed the method of system analysis and design from traditional top-down approach to

bottom-up object-oriented approach. This change in approach has motivated the development of Objectcharts that depict the behavior of objects used in a system.This paper extends the notational capabilities of Objectcharts to specify the issues related to the mobile computing. We discuss the specialty and the limitations found in mobile computing to motivate the readers on the necessity of having methods for developing mobile computing applications. We have shown that making use of all the niceties of Statecharts as well as Objectcharts, the formalism can be extended for developing mobile computing applications. First, we discuss the need for an extension of Objectchart notation by showing the limitations of Objectcharts in specifying mobile computing applications. Second, we propose an extension to Objectcharts,
referred to as Mobicharts. The proposed Mobicharts can specify the important characteristics of mobile computing applications. We illustrate typical mobile computing characteristics such as migration, hoarding, cloning, synchronization, sharing and disconnected operations using Mobicharts.

1. Introduction

Having a well-defined and expressive notation is important to the process of software development. Standard notations make it possible for describing a computing scenario or developing software architecture and then unambiguously communicate these decisions to others. A notation is a vehicle for capturing the reasoning about the behavior and architecture of a system. A number of notations have been reported in literature to specify the behavior of systems, viz. While most of the literature deals with specification of different aspects of object-oriented paradigm, there is very little work on the use of Statecharts or Objectcharts for modeling mobile computing applications. Characteristics of mobile computing environments differ from traditional ones due to various factors, like wireless communication media, limited resources of mobile devices, mobility of users from one place to another, and so on.Mobile computing applications must be aware of the characteristics of the environment, should have the capabilities to overcome the challenges of the environment, and should be able to take advantage of the mobility. We find that the notations reported in literature, such as Statecharts and Objectcharts, are not sufficient to expressively specify mobile computing applications. A Statechart is used to show the state space of a given system, the events that cause a transition from one state to another, and the actions that result from a state change. In, Coleman et al. extended the Statechart formalism referred to as Objectcharts, that have the same features of Statecharts and some more features to model the characteristics of object-oriented systems. Objectcharts model the dynamic behavior of an object in its lifetime. In this paper, we introduce a notation, called Mobicharts, for specifying mobile computing applications. Mobile computing environment, albeit a distributed computing environment, is different due to its typical features of disconnections, and limited resources of mobile host. A mobile computing application is elegant when it is designed to adapt to the location it visits. Though objects can be thought of as building blocks to model mobile computing applications, Objectchart formalism does not provide mechanisms to model the typical features of mobile computing applications. Some important mobile computing features are specifying object location, migration, inheritance, hoarding,cloning, sharing and synchronization. Currently, Objectcharts, do not have clean mechanisms to specify the above features. In this work, we extend the specification of an object with a handler called container. Container of an object not only specifies the object location, but also models inheritance of container properties of the object. We also enrich Mobichart to be capable of to modeling the above features. We show that using Mobicharts, users can design mobile computing applications by specifying application specific actions during the phenomena that occur in a mobile environment. Based on the proposed Mobicharts,we are developing a programming environment in order to automate the development of mobile computing application. In addition, we are working on mobile computing application testing strategies using Mobicharts specifications. Rest of the paper is organized as follows: Section 2 gives a brief overview of Statecharts, and Objectcharts. Section 3 describes characteristics of mobile computing application development environments and system model for the same. In section 4, we illustrate some of the inadequacies of Objectcharts through a process of modeling a mobile computing application. Further, we arrive at solutions to overcome these inadequacies. In section 5, describe in detail Mobicharts and illustrate using Mobicharts different features of mobile computing applications. In section 5.2, the application of mobile host considered earlier is specified using Mobicharts illustrating the expressive power of Mobicharts. The paper concludes with a discussion in section 6.

2. Objectcharts

The life cycle behavior of an object class/system may be modeled by a Statechart. The states of a Statechart represent various stages that an object of a class (or a system) may go through. In other words, a Statechart represents a view of the dynamic model of an entire system in its lifetime. It can also be used to model hierarchy, concurrency, and broadcast communications in a system. Two essential elements of a Statecharts are states and state transitions. A state of an object is a snapshot that depicts the features of an object, its interaction with other objects, action or waiting for other events.An event is some occurrence that causes the state of a system/object to change, and this change of state is called state transition. There are three types of states in a Statechart, namely: OR-states,ANDstates and basic states. Objectchart, which is an extension to Harel's Statechart, describes the state changes in a single class. Objectcharts depict states as rounded boxes, transitions as directed lines between states, and can represent AND and exclusive OR decompositions.

3. Environment and its specifications

Convergence of wireless communication and computing technologies has given rise to mobile computing. This new paradigm allows mobility of user (computing devices) thereby providing anywhere, anytime computing facilities. Mobility of user has increased the possibilities of usage in manifold as compared to distributed computing environment with static network. For example, users can get access to the Internet while on move, can get location specific data etc. A mobile computing environment includes Mobile Support Stations (MSS) and Mobile Hosts (Mhs). Each MSS is responsible for managing a number of mobile hosts in a geographic location called cells. As mobile hosts change their location frequently, some hosts enter a cell and at the same time, some other hosts may leave that cell. The number of mobile hosts present in a cell is dynamic in nature. A host, on entering a cell, announces its entry to the MSS of that cell. The MSS registers the mobile host after proper authentication. The MSS also provides different services to all Mhs residing in its cell, viz., routing information, message forwarding to/from other MSSs, and message queuing services in case of disconnection of Mhs. In an environment, support stations are connected by wired network while wireless network is established among a support station and the hosts residing in the cell (Fig.2). We assume that the mobile hosts communicate only with the MSS residing in that cell. Even if one mobile host wants to communicate to another mobile host, the communication will be made through MSSs of their respective cells. Thus, communication network of an environment comprises of both wired and wireless communication network.

Mobile computing environment is constrained in many ways. Mobile units themselves are resource poor with respect to battery power, processing power, and memory. They are inherently unreliable in the sense that their network connectivity is often achieved through low bandwidth wireless links. In addition, during movement of user (device) from one cell to another (handoff), the device is disconnected from network for unpredictable amount of time. Moreover, to save resources of the device, the users may disconnect themselves for variant periods. Difficulties raised by these constraints are compounded by mobility that induces variability in availability of both communication and computational resources. These severe restrictions have great impact in the design and implementation of mobile computing applications. This motivates the development of new notational specifications to model behavior of mobile computing applications. Application development for mobile computing environment is affected by special characteristics of the environment itself.

3.1. State Model of Environment

In this section, we shall describe the key roles that makes a mobile computing environment. We shall highlight the activities of a mobile host (MH) and a mobile support station (MSS) through typical mobile computing scenarios using Statecharts. Through this, we shall highlight the environment in which applications have to be developed and briefly explain MH, MSS.

3.1.1. States of a Mobile Host:

Here, we model the basic activities of a mobile host. One may view a mobile host in one of the following states, namely, Doze, Join, Active, and Leave. A host, on joining a cell, assumes the state Join, indicating that the host establishes communication link with the cell's MSS. After a host registers itself with the cell's MSS, the host can either be in Active state or Doze state based on its work agenda and external stimuli. An MSS registers a mobile host after obtaining the required information about the host, and updating the databases that keep information about all the hosts present in its cell. A host can change its state from Active to Doze and vice-versa. In Doze state, a host does not do any computation, apart from listening to some external events. In this state, the host reduces its CPU speed to conserve its battery. Active state is composed of four concurrent states/substates, namely, HTx, HRx, Hcomp and Check. In HTx and HRx states, a mobile host performs message transmission and reception respectively.Actual execution of application programs is performed in HComp state. Hcomp state can further be divided into substate to represent computation in either connected or disconnected mode of the device. It must be noted that a host can continue computation in disconnected mode. The Check state concurrently checks for the wireless connectivity to the MSS. This state helps in identifying abrupt unplanned disconnections. In case of disconnection, the Check state generates an event that changes the substates of HComp state from connected to disconnected mode. We assume that a host, before leaving a cell, assumes Doze state, and then assumes Leave state on being disconnected.

3.1.2. States of Mobile Support Station (MSS):

Some of the responsibilities of MSS are: (a) to route messages, (b) to handle wired transmission/ reception of messages to/from devices in fixed network, (c) to handle the wireless transmission/ reception of messages to/from mobile hosts in its cell, (d) to manage the buffers (Mailboxes) to store messages for a host, when the host is disconnected, (e) to keep track of the registration information of incoming and outgoing hosts in the cell and (f) to forward any message to the host after it has moved. These responsibilities/ tasks can be grouped into two broad categories: location management and message handling. Let these activities be called LocMgmt and MsgHandling. The message handling again consists of locating mobile hosts LocateHost and Comm. The MSS finds the location of a host before deciding which type of communication is required. If the location of host is in the cell, then wireless communication would be used.

If a host is in another cell, then LocateHost determines the host location and then forwards the message to corresponding MSS. In this case, the MSS would use wired communication. Two types of associated communications viz. wireless and wired, are performed in states CommAir and CommLand respectively. These two states are concurrent substates of the state Comm. Again each of these two substates, CommAir and CommLand, are composed of two concurrent substates MSSTx and MSSRx, to concurrently transmit and receive the messages simultaneously. The Register substate of LocMgmt registers a mobile user upon arrival in the cell. When a user leaves a cell, the Updatesubstate is used to delete the information about that user. If there is a message for a host after it leaves the cell then the message is directed to the host’s new location. It must be noted that MSS, in addition to work as a base station can participate in execution of an application. Particularly, here it is assumed that MSS stores messages for disconnected hosts and delivers message on reconnection of hosts, and provides ambiences to cloned tasks.

4. An Example Scenario

Here, we present an application that uses mobile agents on a wireless network. We also attempt to model the application using Objectchart to identify its inadequacies. A mobile computing application can be modeled by a set of interoperable objects located in different mobile hosts collaborating by passing messages among themselves.Consider a stock market broker, who has a mobile computing device. The broker has many shareholders as his business clients. The broker's businesses is to send current information about stock prices to shareholders and then get feedback from them regarding their decisions to purchase or sell shares. Some of the shareholders may have mobile devices and some others have PCs connected to a fixed network. We are interested in those having mobile devices. The stockbroker uses his mobile device to engage software agents for following purposes:

The agents collect information about the status of stock prices from central database of stock market.

The agents send the collected information to shareholders and then visit each of them to get their individual decisions regarding purchase/selling of shares.

After collecting this information from shareholders, the agents come back to the broker and the broker uses this information for actual selling/purchase of shares on behalf of his customers. This example presents various aspects of mobility as described below:

a) While in search for shareholders on the network, the software agents may find the shareholder's device in disconnected mode. b) While an agent complete its tasks in a shareholder's device, may find the device to be disconnected from the rest of the world

c) When an agent visits several shareholder’s devices in sequence, to collect the information from each of them, it may not be possible for the agent to complete the task in stipulated time. This is possible, because, an agent doing its work in a mobile device may find the device to be in disconnected mode. So,the agent cannot move forward to other shareholder until the device is reconnected.

d) When an agent, after collecting information from shareholders, wants to return to the broker, it may find the broker's device to be in disconnected mode. The agents may clone themselves at different situations to increase parallelism of work done at different places. For example, in situation (a) above, when the software agent inquires the MSS about all hosts present in the MSS's cell, it may find some devices to be in active state and some others in disconnected state. In this situation, the agent clones itself on the MSS, delegating the task of information collection from mobile hosts in that cell to the cloned agent/task. Then, the original agent moves forward in quest of finding other potential shareholders at different MSS. In scenario (b), an agent doing its task of information collection may inquire the device of any planned disconnection in the device's schedule. If the agent cannot complete its task before the disconnection, the agent may clone itself and move on to other hosts. The cloned agent would take care of information collection from user, and wait for the host to get reconnected. As soon as the device reconnects, the cloned agent would return to the broker with the collected information. The scenario (c) can be taken care of again by cloning to increase the parallelism of computation at the MSS level or at the mobile device level. In case (d), when an agents returns to the broker's MSS, and finds that the broker's device is disconnected, the agents have to wait in the MSS until the broker reconnects again. Since, the same replica of the stock prices information is being circulated to all mobile clients, this can be thought of as shared data. The shared data resides on the MSS of the stock market and the MSS keeps a list of all the devices that are going to share the data. The software agent from the broker can provide this information to the MSS. Whenever there is some minor update on shared data, the MSS's responsibility is to propagate the updates to all devices that are sharing the data.

4.1. Modeling the Example by Objectcharts

In figure 6, we give the object chart for the task of agent in a mobile host described in previous section. In this figure, we assume that upon joining a host device, the task assumes Join state. A task can join a host, when it is in Active state only. If a host is in Passive state, it comes to Active state on receiving wake-up signal from the MSS and then receives the task that wishes to join/migrate to the host. The Monitor substate of Active state is meant for monitoring the state of the device and take action accordingly. In addition, if the task on the client is over, it has to migrate itself to another host. In our application scenario, if the software agent has collected the information required from one shareholder, the agent moves to another host. Before migrating itself, the task will go to Passive state and save the computation. In this state, a task polls messages that are pending for the task on host message queue. If the message queue for the task is empty, the task moves from Passive state to Leave state.

The Compute substate of Active state specifies computation due to the task.The substate Compute can further be refined to specify/model the computational details of the task. The detailed model can show how the agent performs the task, what all variables are changed after the information from one shareholder has been obtained, and so on. The object chart shows the sequence of state transitions required for the agent tasks to interface with the computing environment. Here, we observe that, the state transition from Active state to Passive state is ambiguous. The same transition is followed from Active state with two different events 'doze' / 'move' or 'migrate', with the final state

being Passive state. In addition, we observe that the Objectchart is inadequate to represent

the following:

i) It cannot represent location based state transition e.g. based on location of the agent at a particular place, say near stock exchange, the agent could take specific action.

ii) It cannot represent the unpredictable nature of state transitions of a task.

iii) It cannot represent Object's ambience and inheritance among ambient objects.

iv) It may be noted here that the Leave state of the task is not a terminated state i.e. the task has not finished its execution. Rather, this state may be seen as a Frozen state, in which a task can sail through network in dormant mode to resume its active execution elsewhere. This behavior of task is known as Task Migration and during this process, state of the task is preserved. Objectchart specifications do not explicitly specify these

characteristics of task.

v) Another feature of the scenario application is that, in the Active Compute state, a task can clone itself at the device and then migrate to another device through the network.

vi)A task, having the responsibility of updating the shared data by communicating the changes to all sharing devices, cannot predict when the update operation would be over. So, the behavior of such tasks depends on behavior of some other mobile devices on the network. This behavior of task cannot be captured by Objectcharts.

5. Mobicharts

In this section, we extend Objectcharts to support the design and development of mobile computing applications. We describe a set of services to ease the process of mobile computing application design and development. Further, the following additional features are added to enrich Objectcharts to overcome the inadequacies highlighted earlier:

A disconnected state: A special state designated as 'Disconnected', and drawn in dotted lines, is inserted between every two states, between which the objects/task can be disconnected. This state handles all messages

destined for the object during disconnected state, by maintaining a message queue in the 'container' and storing all messages in it until the object again enters the Connected state.

Container (handle): Each state of an object is associated with the operating environment called its container. The container (handle) is used to represent the location of an object. Containers in Mobicharts enable us to model the location of the object. Other user-defined

data items that are to be changed every time the location changes can also be handled using the container handle by incorporating them in the container. In conventional Objectcharts, we can only model states of an object. Here, we are able to model states of an object at a particular location. It also models the inheritance of container Properties by the object. So, a container for task/object could be a mobile host or it could be a MSS or container for mobile host could be the MSS of the cell in which the host resides. All mobile objects/tasks have certain essential functionality/services that are required for implementing other features of the application. The services that can be used on demand are as follows:

(a) Migration: Every task has to migrate from one host to another or from a host to a MSS and viceversa at some point of time, to perform some action. Steps are:

Task to be migrated is first 'Frozen' and then transmitted to the destination.

The frozen task at destination is reactivated

All messages for the task to be migrated are stored in the corresponding message queue in the previous host.Mobicharts notation for task migration is shown in figure 7 (b). Currloc is the handler for the task in frozen and disconnected state. The handler provides the location of the object on hand. The state Disconnected with the Currloc shows that the object in migration is not able to migrate due to disconnection of the host. If there is a disconnection by the source host device, then the task goes to the Disconnected state and waits for the event reconnected. Upon reconnection, the transition from Disconnected to Newloc-Frozen state by the action Join (Newloc) takes place. In case there is no disconnection of the device, then the transition Leave and Join merge into a single one. The introduction of disconnected state helps us to model the unpredictable behavior of the task.

(b) Inheritance: When an object joins a new container, all variables qualified with the keyword inherit in the object are automatically updated with values of corresponding variables in the container.

(c) Hoarding: To continue computation, a task in disconnected state, may require some data stored in a place other than the device where the task is executing. Thus, prior to disconnection, the data could be fetched and stored in local buffer for later usage during disconnection. This hoarding of information may require the user to specify the items to be hoarded and the sources from where they have to be fetched (usually the MSS). In addition, the task on hand or the application may specify the items to be hoarded. Once this information regarding hoarding data and their locations are acquired,

Service takes care of maintaining the buffers, connecting service takes care of maintaining the buffers, connecting to the data sources and hoarding the information until disconnection occurs. If the hoarded items are updated to the data sources and hoarding the information until disconnection occurs. If the hoarded items are updated during disconnection, reconciliation of data is performed by this service whenever it is necessary, like upon reconnection or on specific request by the task.

(d) Cloning: A task may require creating a new task with the same functionality or a scaled down task. Cloning is used to make an exact replica of an executing task. The rules followed are: (a) the task should be in active state before cloning, (b) The cloned task becomes a new task by joining the host and then continuing execution, and (c) A cloned task could be a downsized task.

(e) Sharing: Sharing and synchronization are for cooperating tasks, which execute concurrently. When a task wants to share some variables with other tasks, it declares the variables as shared, and this task is known as the owner task of these variables. Other tasks wishing to use the variable register themselves with owner task and maintain a copy of the variables.Whenever a shared variable is updated in the owner task, messages are passed by the owner task to all registered tasks accessing the shared data. Tasks are allowed for read-only access of the shared variables present in the owner task. The Mobicharts notation is shown in figure 11 (b). Here, after sending update messages to the , the owner task waits to receive acknowledgements from other tasks. If timeout of message occurs, the message is sent again. This is continued either for a predetermined number of times or for a predetermined amount of time.If no acknowledgement is received from other tasks, they are assumed to be either disconnected state or are no longer existing.

So, the owner task removes the task entries from the <tasklist> and continues. After the owner task receives acknowledgement from all other tasks in the <tasklist>, then only it continues its own operation/computing.

(f) Synchronization: This service could be thought of as an application of read-write sharing. Whenever, pieces of codes need to be synchronized in two or more tasks, they can use a global variable and a predicate on that variable. The global variable is kept globally on the MSS to reduce communication overhead. This global variable is taken care of by this synchronization service. The predicate on global variable is used as the execution condition for the method that require synchronization. If the predicate on global variable evaluates to true, then the method is

executed; other wise, the task continues to apply the predicate on the global variable. Mobicharts for the synchronization service is shown in figure.

5.1 Developing Mobicharts

Here, we describe the steps to be followed for a systematic development of Mobicharts specification of applications:

a) Enumerate the tasks to be performed by application. Identify the tasks/objects that might be using services like migration, hoarding etc. Identify the hoarding information that might be used while application executes. Identify potential methods of tasks/objects that might need synchronization. Also find out potential variables that may be shared by different objects and make list of all tuples <shared variable, tasklist>. Enumerate inherited variables of the objects or tasks.

b) For all major tasks/objects classes, enumerate their possible states and state transitions. Also, find the type of services these tasks offer and the services they may

require from other tasks/objects.

c) For conventional state transitions, use Objectchart notation to depict the behavior.

d) Within a location transition, there is a possibility of disconnection.Between such states of tasks/objects,insert/introduce another state Disconnected.

e) Enumerate all possible locations that the object/task may go through. For each state of an object,mention the location with the help of container handler.

f) For each object/task in application, associate a message queue at all location they may visit in their lifetime.

g) With respect to state transitions that require the services offered by Mobicharts,use Mobi charts notation to describe the state transition services.

5.2. Mobichart Specification of a Task

Here we give the detailed mobichart specification of the Compute substate of the Active state (cf. figure 6) of a task in a host. In this state, a task has two more substate, namely, Connected and Disconnected. In Disconnected substate, a task may continue to execute independently using the hoarded information in the state DisconnectedExecute’ In the Connected state, there are two concurrent executions, one for executing the task and the other for hoarding of information.The Mobicharts specification is shown in figure13.

6. Conclusion

Mobilecomputing environment is a kind of distributed computing environment but with characteristics like mobility of systems, their limited resources and intermittent disconnections in network due to environmental vagaries. A mobile computing application can be modeled by a set of interoperable objects located in different mobile hosts and collaborate by passing messages among themselves. While objects may move to different hosts, hosts can change locations (cells). A simple mobile computing application can be thought of as a collection of actions corresponding to events.The event-action paradigm is a generic computing model and object oriented design approaches like UML and Objectcharts can be used to model applications in this paradigm. As discussed in section 4, these classical design approaches are not suitable to model typical characteristics viz. location awareness, migration, hoarding, synchronization, cloning, sharing and disconnection management. In the proposed Mobicharts– an extension of Objectchart – has visual specifications to model these characteristics. Hence, an application designer not only can use Mobicharts to specify state changes of objects participating in this application but also can model system behaviors during the phenomena that are special to this computing

environment. Based on the proposed Mobicharts, we are developing a programming environment in order to automate the mobile computing application development process. In addition, we propose to develop a mobile computing application testing strategies using specifications made in Mobicharts.

References

[1] Grady Booch, "Object-Oriented Analysis and Design with Applications", Redwood City, Benjamin Cummings, 1994

[2] Derek Coleman, Fiona Hayes and Stephen Bear, "Introducing Objectcharts or How to Use Statecharts in Object- Oriented Design", IEEE Transaction on Software Engineering.

[3] Fiona Hayes & Derek Coleman, "Coherent Models for Object Oriented Analysis", Proceedings of ACM, OOPSLA'91

[4] Stephen Bear, Phillip Allen, Derek Coleman & Fiona Hayes, "Graphical Specification of Object Oriented Systems", Proceedings of ECOOP/OOPSLA'90- 37

[5] David Harel & Amnon Naamad, "The STATEMATE Semantics of Statecharts", ACM Transaction on Software Engineering & Methodologies, Vol.5, No.4, October 1996,

[6] Fernam Jahanian & Aloysius K. Mok, "Modechart: A Specification Language for Real time Systems",IEEE Transaction on Software Engineering, Vol. 20

[7] Stuart Kent, "Constraint Diagrams: Visualizing Invariants in Object Oriented Models", Proceedings of OOPSLA'97

[8] Arthur Allen & Dennis de Champeaux, "Extending the Statechart Formalism: Event Scheduling & Dispositions".

[9] George Samaras, Evaggelia Pitoura, "Computational Models for Wireless & Mobile Environments", University of Cyprus

[10] D. Harel, "Statecharts: A Visual Formalism for Complex Systems", Technical Report, The Weizmann Institute of Science, Israel, July 1986

[11] Grady Booch, James Rambaugh, Ivar Jacobson, “The Unified Modeling Language User Guid”, Low Price Edition, Pearson Education, Inc., 1999

[12] V. Anil Kumar, Maruthi, “Mobile Charts – A Notation for Developing Mobile Computing Applications”, M.Tech Thesis, Department of Computer Science, University of Hyderabad, December 2001

Network and Security

2012-06-25T13:40:00.001-07:00

Network and security

ABSTRACt:

In this modern fast world network is a very important factor to share our data with our friends / relatives. But in this competitive world many intruders are hacking the precious data that we are sending. Here in this paper we are going to discuss about network and some valuable steps/algorithms to protect the data in the network. Beyond that we are going discuss something about firewall which is the latest trend in network security.

INTRODUCTION:

We know that network is nothing but interconnection of systems for sharing of information. In that network there will be loss of data due to some external disturbances. Beyond that there is no security for the data that we are sending through the network by the hackers. To safeguard our data we are going to handle some methods, which is more efficient to have secure communication over insecure channels.

Common threats overview:

Computer systems are vulnerable to many threats that can inflict various types of damage resulting in significant losses. The effects of various threats vary considerably: some effect the confidentiality or integrity of data while others affect the availability of IP’s.

HACKERS TECHNICS:

Eavesdrop and replay.
Spoofing.
Session hijacking.
Sniffing.
Man in the middle.
Exploring back doors.
Scanning through fire walls.
Denial of services.

TECHNIQUES FOR SECURITY:

Ø Cryptography

Ø Authentication

Ø Message integrity

Ø Key distribution

CRYPTOGRAPHY:

Ø Cryptography is a branch of mathematics based on the transformation of data.

Ø Cryptography is a science and art of manipulating messages to make them secure.

CRYPTOGRAPHY USED FOR VARIOUS PURPOSES:

To authenticate remote users.
To verify that files were not tempered with.
To certify digital documents.

Cryptography is traditionally associated only with keeping data secret. However, modern cryptography can be used to provide many security services, such as electronic signatures and ensuring that data has not been modified. There are two basic types of cryptography: "secret key" and "public key.". It provides an important tool for protecting information and is used in many aspects of computer security. For example, cryptography can help provide data confidentiality, integrity, electronic signatures, and advanced user authentication. Although modern cryptography relies upon advanced mathematics, users can reap its benefits without understanding its mathematical underpinnings. This chapter describes cryptography as a tool for satisfying a wide spectrum of computer security needs and requirements. It describes fundamental aspects of the basic cryptographic technologies and some specific ways cryptography can be applied to improve security. The chapter also explores some of the important issues that should be considered when incorporating cryptography into computer systems.

Basic Cryptographic Technologies:

Cryptography relies upon two basic components: an algorithm (or cryptographic methodology) and a key. In modern cryptographic systems, algorithms are complex mathematical formulae and keys are strings of bits. For two parties to communicate, they must use the same algorithm (or algorithms that are designed to work together). In some cases, they must also use the same key. Many cryptographic keys must be kept secret; sometimes algorithms are also kept secret. There are two basic types of cryptography: Secret key systems (also called symmetric systems) and public key systems (also called Asymmetric systems). Table 19.1 compares some of the distinct features of secret and public key systems. Both types of systems offer advantages and disadvantages. Often, the two are combined to form a hybrid system to exploit the strengths of each type. To determine which type of cryptography best meets its needs, an organization first has to identify its security requirements and operating environment.

DISCREET FUNCTIONS	SECRET KEY CRYPTOGRAPHY	PUBLIC KEY CRYPTOGRAPHY
NUMBER OF KEYS	Single key.	Pair of keys.
TYPES OF KEYS	Key is secret.	One key is private & one key is public.
PROTECTION OF KEYS	Disclosure and Modification.	Disclosure and Modification for private keys and modification for public keys.
RELATIVE SPEEDS	Faster.	Slower. Slower. Slower. Slower.

Secret Key Cryptography:

In secret key cryptography, two (or more) parties share the same key, and that key is used to encrypt and decrypt data. As the name implies, secret key cryptography relies on keeping the secret. If the key is compromised, the security offered by cryptography is severely reduced or eliminated. Secret key cryptography assumes that the parties who share a key rely upon each other not to disclose the key and protect it against modification.

The best known secret key system is the Data Encryption Standard (DES), published by NIST as Federal Information Processing Standard (FIPS) 46-2. Although the adequacy of DES has at times been questioned, these claims remain unsubstantiated, and DES remains strong. It is the most widely accepted publicly available cryptographic system today. The American National Standards Institute (ANSI) has adopted DES as the basis for encryption, integrity, access control, and key management standards. The Escrowed Encryption Standard, published as FIPS 185, also makes use of a secret key system.

Secret key cryptography has been in use for centuries. Early forms merely transposed the written characters to hide the message.

Public Key Cryptography:

Whereas secret key cryptography uses a single key shared by two (or more) parties, public key cryptography uses a pair of keys for each party. One of the keys of the pair is "public" and the other is "private." The public key can be made known to other parties; the private key must be kept confidential and must be known only to its owner. Both keys, however, need to be protected against modification. Public key cryptography is particularly useful when the parties wishing to communicate cannot rely upon each other or do not share a common key. There are several public key cryptographic systems. One of the first public key systems is RSA, which can provide many different security services. The Digital Signature Standard (DSS), described later in the chapter, is another example of public key system.

Hybrid Cryptographic Systems:

Public and secret key cryptography have relative advantages and disadvantages. Although public key cryptography does not require users to share a common key, secret key cryptography is much faster: equivalent implementations of secret key cryptography can run 1,000 to 10,000 times faster than public key cryptography. To maximize the advantages and minimize the disadvantages of both secret and public key cryptography, a computer system can use both types in a complementary manner, with each performing different functions. Typically, the speed advantage of secret key cryptography means that it is used for encrypting data. Public key cryptography is used for applications that are less demanding to a computer system's resources, such as encrypting the keys used by secret key cryptography (for distribution) or to sign messages.

Key Escrow:

Because cryptography can provide extremely strong encryption, it can thwart the government's efforts to lawfully perform electronic surveillance. For example, if strong cryptography is used to encrypt a phone conversation, a court-authorized wiretap will not be effective. To meet the needs of the government and to provide privacy, the federal government has adopted voluntary key escrow cryptography. This technology allows the use of strong encryption, but also allows the government when legally authorized to obtain decryption keys held by escrow agents. NIST has published the Escrowed Encryption Standard as FIPS 185.

Voluntary key escrow initiative, the decryption keys are split into parts and given to separate escrow authorities. Access to one part of the key does not help decrypt the data; both keys must be obtained.

Uses of Cryptography:

Cryptography is used to protect data both inside and outside the boundaries of a computer system. Outside the computer system, cryptography is sometimes the only way to protect data. While in a computer system, data is normally protected with logical and physical access controls (perhaps supplemented by cryptography). However, when in transit across communications lines or resident on someone else's computer, data cannot be protected by the originator's logical or 134 physical access controls. Cryptography provides a solution by protecting data even when the data is no longer in the control of the originator.

conclusion:

This document provides the readers with introductory information to network and security. Cryptography and watermarking are core technologies. Every new technology will bring new security problems, so achieving 100% security is impossible. Many algorithms have been introduced to safely send our data through the network. We are also having the implementation for transposition cipher cipher. If we got the opportunity to present the paper we will do it well with our implementation.

3G MOBILE COMMUNICATION

2010-01-15T05:26:00.001-08:00

&&&&&3GMOBILE COMMUNICATION&&&&&

3G network --> ABSTRACT

2010-01-15T05:24:00.000-08:00

3rd Generation Wireless, or 3G, is the generic term used for the next generation of mobile communications systems. 3G systems aim to provide enhanced voice, text and data services to user. The main benefit of the 3G technologies will be substantially enhanced capacity, quality and data rates than are currently available.

3G Mobile will enable the provision of advanced services transparently to the end user and will bridge the gap between the wireless world and the computing/Internet world, making inter-operation apparently seamless.

The third generation networks should be in a position to support real-time video, high-speed multimedia and mobile Internet access. All this should be possible by means of highly evolved air interfaces, packet core networks, and increased availability of spectrum.

The ability to provide high-speed data is one of the key features of third generation networks, the real strength of these networks will be providing enhanced capacity for high quality voice services. The need for landline quality voice capacity is increasing more rapidly than the current 2nd generation networks will be able to support.

High data capacities will open new revenue sources for the operators and bring the Internet more closer to the mobile customer. The use of all-ATM or all-IP based communications between the network elements will also bring down the operational costs of handling both voice and data, in addition to adding flexibility.

The drive for 3G is the need for higher capacities and higher data rates. Whereas higher capacities can basically be obtained by having a greater chunk of spectrum or by using new evolved air interfaces, the data requirements can be served to a certain extent by overlaying 2.5G technologies on the existing networks. In many cases it is possible to provide higher speed packet data by adding few network elements and a software

The 3rd Generation Mobile System will most likely grow out of the convergence of enhanced 2nd generation mobile systems with greater data transfer speed and capacity and 1st generation satellite mobile systems. Evolution to the current generation mobile networks to 3G doesn't necessarily mean seamless up gradation to the existing infrastructure to the 3G.

3G --> CONTENTS

2010-01-15T05:20:00.000-08:00

1. INTRODUCTION

2. A GLOBAL VISION TO 3G MOBILE

3. 3G ARCHITECTUE

4. CHARECTRISTICS OF 3G

5. EVOLUTION TOWARDS 3G

6. SECURITY ASPECTS

7. 3G SECURITY FEATURES

8. CONCLUSION

1. 3G --> Introduction

2010-01-15T05:18:00.000-08:00

2. 3G --> A Global Vision to 3G Mobile

2010-01-15T05:12:00.000-08:00

“The IMT-2000 third generation mobile standard enables mobile users to harness the
full power of the Internet through efficient high-speed radio transmission, optimized for multimedia communications”

3. 3G Architecture

2010-01-15T05:08:00.000-08:00

The 3G network will have a layered architecture, which will enable the efficient delivery of voice and data services. A layered network architecture, coupled with standardized open interfaces, will make it possible for the network operators to introduce and roll out new services quickly

These networks will have a connectivity layer at the bottom providing support for high quality voice and data delivery. Using IP or ATM or a combination of both, this layer will handle all data and voice info.

The layer consists of the core network equipment like routers, ATM switches and transmission equipment. Other equipment provides support for the core bit stream of voice or data, providing QOS etc.

In 3G networks, voice and data will not be treated separately which could lead to a reduction in operational costs of handling data separately from voice. The application layer on top will provide open application service interfaces enabling flexible service creation. This user application layer will contain services for which the end user will be willing to pay. These services will include eCommerce, GPS and other differentiating services. In between the application layer and the connectivity layer, will run the control layer with MSC servers, support servers, HLR etc. These servers are needed to provide any service to a subscriber.

4. 3G --> Characteristics of 3G

2010-01-15T05:00:00.000-08:00

The main characteristics of 3G systems, known collectively as IMT–2000, are a single family of compatible standards that have the following characteristics:

• Used worldwide

• Used for all mobile applications

• Support both packet-switched (PS) and circuit-switched (CS) data transmission

• Offer high data rates up to 2 Mbps (depending on mobility/velocity)

• Offer high spectrum efficiency

Figure 1. Multiple Standards for Different Applications and Countries

IMT–2000 is a set of requirements defined by the International Telecommunications Union (ITU). As previously mentioned, IMT stands for International Mobile Telecommunications, and “2000” represents both the scheduled year for initial trial systems and the frequency range of 2000 MHz. All 3G standards have been developed by regional Standards Developing Organizations (SDOs). In total, proposals for 17 different IMT–2000 standards were submitted by regional SDOs to ITU in 1998—11 proposals for terrestrial systems and 6 for Mobile Satellite Systems (MSSs). Evaluation of the proposals was completed at the end of 1998, and negotiations to build a consensus among differing views were completed in mid 1999. All 17 proposals have been accepted by ITU as IMT–2000 standards. The specification for the Radio Transmission Technology (RTT) was released at the end of 1999.

The most important IMT–2000 proposals are the UMTS (W-CDMA) as the successor to GSM, CDMA2000 as the interim standard ’95 (IS–95) successor, and time division–synchronous CDMA (TD–SCDMA) (universal wireless communication–136 [UWC–136]/EDGE) as TDMA–based enhancements to D–AMPS/GSM—all of which are leading previous standards toward the ultimate goal of IMT–2000.

UMTS allows many more applications to be introduced to a worldwide base of users and provides a vital link between today’s multiple GSM systems and IMT–2000. The new network also addresses the growing demand of mobile and Internet applications for new capacity in the overcrowded mobile communications sky. UMTS increases transmission speed to 2 Mbps per mobile user and establishes a global roaming standard.

UMTS is being developed by Third-Generation Partnership Project (3GPP), a joint venture of several SDOs—ETSI (Europe), Association of Radio Industries and Business/Telecommunication Technology Committee (ARIB/TTC) (Japan), American National Standards Institute (ANSI) T-1 (USA), telecommunications technology association (TTA) (South Korea), and Chinese Wireless Telecommunication Standard (CWTS) (China). To reach global acceptance, 3GPP is introducing UMTS in phases and annual releases. The first release (UMTS Rel. ’99), introduced in December of 1999, defines enhancements and transitions for existing GSM networks. For the second phase (UMTS Rel. ’00), similar transitions are being proposed as enhancements for IS–95 (with CDMA2000) and TDMA (with TD–CDMA and EDGE).

The most significant change is the new UMTS Terrestrial Radio Access (UTRA), a W–CDMA radio interface for land-based communications. UTRA supports time division duplex (TDD) and frequency division duplex (FDD). The TDD mode is optimized for public micro and pico cells and unlicensed cordless applications. The FDD mode is optimized for wide-area coverage, i.e., public macro and micro cells. Both modes offer flexible and dynamic data rates up to 2 Mbps. Another newly defined UTRA mode, multicarrier (MC), is expected to establish compatibility between UMTS and CDMA2000.

5. 3G --> Evolution towards 3G

2010-01-15T04:56:00.000-08:00

Phase 1 of the standardization of GSM900 was completed by the European Telecommunications Standards Institute (ETSI) in 1990 and included all necessary definitions for the GSM network operations. Several tele services and bearer services have been defined (including data transmission up to 9.6 kbps), but only some very basic supplementary services were offered. As a result, GSM standards were enhanced in Phase 2 (1995) to incorporate a large variety of supplementary services that were comparable to digital fixed network integrated services digital network (ISDN) standards. In 1996, ETSI decided to further enhance GSM in annual Phase 2+ releases that incorporate 3G capabilities.

GSM Phase 2+ releases have introduced important 3G features such as intelligent network (IN) services with customized application for mobile enhanced logic (CAMEL), enhanced speech compression/decompression (CODEC), enhanced full rate (EFR), and adaptive multirate (AMR), high–data rate services and new transmission principles with high-speed circuit-switched data (HSCSD), general packet radio service (GPRS), and enhanced data rates for GSM evolution (EDGE). UMTS is a 3G GSM successor standard that is downward-compatible with GSM, using the GSM Phase 2+ enhanced core.

The swift migration from 2G to 3G and their bandwidth used are as in the Figure.

6. 3g --> Security Aspects

2010-01-15T04:53:00.000-08:00

• Network Authentication
The user can identify the network
• Explicit Integrity
Data integrity is assured explicitly by use of integrity algorithms
Also stronger confidentiality algorithms with longer keys
• Network Security
Mechanisms to support security within and between networks

• Switch Based Security
Security is based within the switch rather than the base station
• IMEI Integrity
Integrity mechanisms for IMEI provided from the start
• Secure Services
Protect against misuse of services provided by SN and HE
• Secure Applications
Provide security for applications resident on USIM
• Fraud Detection
Mechanisms to combating fraud in roaming situations
• Flexibility
Security features can be extended and enhanced as required by new threats and services
• Visibility and Configurability
Users are notified whether security is on and what level of security is available.
Users can configure security features for individual services

7. 3G Security Features

2010-01-15T04:48:00.000-08:00

Mutual Authentication
During Authentication and Key Agreement (AKA) the user and network authenticate each other, and also they agree on cipher and integrity key (CK, IK). CK and IK are used until their time expires.
Assumption: trusted HE and SN, and trusted links between them.
After AKA, security mode must be negotiated to agree on encryption and integrity algorithm.

8. 3G Network --> Conclusion

2010-01-15T04:33:00.000-08:00

Standardization of 3G mobile systems is based on ITU (International Telecom Union) recommendations for IMT 2000. IMT 2000 specifies a set of requirements that must be achieved 100% for a network to be called 3G. By providing multimedia capacities and higher data rates, these systems will enhance the range and quality of services provided by 2G systems.
The main contenders for 3G systems are wideband CDMA (W-CDMA) and CDMA2000. The ETSI/ GSM players including infrastructure vendors such as Nokia and Ericsson backed W-CDMA. cdma2000 was backed by the North American CDMA community, led by the CDMA Development Group (CDG) including infrastructure vendors such as Qualcomm and Lucent Technologies. Universal Mobile Telephone System (UMTS) is the widely used European name for 3G.
The proposed IMT-2000 standard for third generation mobile networks globally is a CDMA-based standard that encompasses THREE OPTIONAL modes of operation, each of which should be able to work over both GSM MAP and IS-41 network architectures.
UMTS is the European designation for 3G systems. The UMTS frequency bands selected by the ITU are 1,885 MHz - 2,025 MHz (Tx) and 2,110 MHz - 2,2,20 MHz (Rx). Higher frequency bands could be added in future if need be, for stationary data. There is still some confusion about all the frequency options as FCC has not given clear indications so far. The following table should briefly give an idea about the 3G system specifications.

3D-FACE RECOGNITION

2010-01-14T05:29:00.000-08:00

3D-Face Recognition Using The Fishersurface Method And Surface Space Combinations

Abstract

2010-01-14T05:28:00.001-08:00

In this paper we test a range of three-dimensional face recognition systems, based on the fishersurface method developed in previous work. We show the effect of using a variety of facial surface representations and suggest a method of identifying and extracting useful qualities offered by each system. Combing these components into a unified surface subspace, we create a three dimensionalface recognition system producing significantly lower error rates than individual systems tested on the same data. We evaluate systems by performing up to 1,079,715 verification operations on a large test set of 3D face models. Results are presented in the form of false acceptance and false rejection rates, generated by varying a decision threshold applied to a distance metric in combined surface space.

3D Faces --> INGREDIENTS

2010-01-14T05:27:00.000-08:00

o Introduction

o Fisher surface method

o Test database

o Surface space analysis

o Combining systems-multiple face recognition

o Test procedure

o Results

o Conclusion

3D Faces --> Introduction

2010-01-14T05:25:00.000-08:00

Despite significant advances in face recognition technology, it has yet to achieve levels of accuracy required for many commercial and industrial applications. The high error rates stem from well-known sub-problems. Variation in lighting, facial expression and orientation all significantly increase error rates. In an attempt to address these issues, research has begun to focus on the use of three-dimensional face models, motivated by three main factors. Firstly, relying on geometric shape, rather than colour and texture information, systems become invariant to lighting conditions. Secondly, the ability to rotate a facial structure in three-dimensional space, allowing for compensation of variations in pose, aids those methods requiring alignment prior to recognition. Thirdly, the additional depth information in the facial surface structure, not available from twodimensional images, provides supplementary cues for recognition.

In this paper we expand on previous research involving the use of facial surface data, derived from 3D face models (generated using a stereo vision 3D camera), as a substitute for the more familiar two-dimensional images. A number of investigations have shown that three-dimensional structure can be used to aid recognition. Zhao and Chellappa use a generic 3D face model to normalise facial orientation and lighting direction in two-dimensional images, increasing recognition accuracy from
approximately 81% (correct match within rank of 25) to 100%. Similar results are witnessed in the Face Recognition Vendor Test , showing that pose correction using Romdhani et al’s technique reduces error rates when applied to the FERET database.

Blanz et al [5] take a comparable approach, using a morphable face model to aid in identification of 2D images. Beginning with an initial estimate of lighting direction and face shape, Romdhani et al iteratively alters shape and texture parameters of the morphable face model, minimising difference to the two-dimensional image. These parameters are then taken as features for identification, resulting in 82.6% correct identifications on a test set of 68 people.
Although these methods show that knowledge of three-dimensional face shape can aid normalisation for two-dimensional face recognition systems, none of the methods mentioned so far use actual three-dimensional geometric structure to perform recognition. Whereas Beumier and Acheroy [6, 7] make direct use of such information, testing various methods of matching 3D face models, although few were successful.

Curvature analysis proved ineffective, and feature extraction was not robust enough to provide accurate recognition. However, Beumier and Acheroy were able to achieve reasonable error rates using curvature values of vertical surface profiles. Verification tests carried out on a database of 30 people produced equal error rates (EER) between 7.25% and 9.0%. Hesher et al test a different method, using PCA (principal component analysis) of depth maps and euclidean distance to perform identification with 94% accuracy on 37 face models (when trained on the gallery set). Further investigation into this approach is carried out by Heseltine et al, showing how different surface representations and distance measures affect recognition, reducing the EER from 19.1% to 12.7% when applied to a difficult test set of 290 face models. However, the focus of this research has been on identifying optimum surface representations, with little regard for the advantages offered by each individual representation.

We suggest that different surface representations may be specifically suited to different capture conditions or certain facial characteristics, despite a general weakness for overall recognition. For example, curvature representations may aid recognition by making the system more robust to inaccuracies in 3D orientation yet also be highly sensitive to noise. Another representation may enhance nose shape, but lose information regarding jaw structure.

In this paper we analyse and evaluate a variety of three-dimensional fishersurface face recognition systems, each incorporating a different surface representation of facial structure. We propose a means of identifying and extracting components from the surface subspace produced by each system, such that they may be combined into a single unified subspace. Pentland et al [10] have previously examined the benefit of using multiple eigenspaces, in which specialist subspaces were constructed for various facial orientations, from which cumulative match scores were able to reduce error rates. Our approach differs in that we extract and combine individual dimensions, creating a single unified surface space, as applied to two-dimensional images in previous investigations.

3D Faces --> The Fishersurface Method

2010-01-14T05:12:00.000-08:00

In this section we provide details of the fishersurface method of face recognition. We apply PCA and LDA (linear discriminant analysis) to surface representations of 3D face models, producing a subspace projection matrix, as with Belhumier et al’s fisherface approach [12], taking advantage of ‘within-class’ information, minimising variation between multiple face models of the same person, yet maximising class separation. To accomplish this we use a training set containing several examples of each subject, describing facial structure variance (due to influences such as facial expression), from one model to another. From the training set we compute three scatter matrices, representing the within-class (SW), between-class (SB) and total (ST) distribution from the average surface _ and classes averages _n, as shown in equation 1.

The training set is partitioned into c classes, such that all surface vectors ni in a single class Xn are of the same person and no person is present in multiple classes. Calculating eigenvectors of the matrix ST, and taking the top 250 (number of surfaces minus number of classes) principal components, we produce a projection matrix Upca. This is then used to reduce dimensionality of the within-class and between-class scatter matrices (ensuring they are non-singular) before computing the top c-1 eigenvectors of the reduced scatter matrix ratio, Ufld, as shown in equation 2.

Finally, the matrix Uff is calculated, such that it projects a face surface vector into a reduced space of c-1 dimensions, in which between-class scatter is maximised for all c classes, while within-class scatter is minimised for each class Xn. Like the fisherface system [12], components of the projection matrix Uff can be viewed as images, as shown in Figure 1 for the depth map surface space.

Figure 1: The average surface (left) and first five fishersurfaces (right)
Once surface space has been defined, we project a facial surface into reduced surface
space by a simple matrix multiplication, as shown in equation 3.

^=(p−!)TU (3)

The vector _T___1__2____c-1] is taken as a ‘face-key’ representing the facial structure in reduced dimensionality space. Face-keys are compared using either euclidean or cosine distance measures as shown in equation 4.

An acceptance (facial surfaces match) or rejection (surfaces do not match) is determined by applying a threshold to the distance calculated. Any comparison producing a distance value below the threshold is considered an acceptance.

3D Face --> The Test Database

2010-01-14T05:04:00.000-08:00

Until recently, little three-dimensional face data has been publicly available for research and nothing towards the magnitude required for development and testing of threedimensional face recognition systems. In these investigations we use a new database of 3D face models, recently made available by the University of York, as part of an ongoing project to provide a publicly available 3D Face Database . Face models are generated in sub-second processing time from a single shot with a 3D camera, using a stereo vision technique enhanced by light projection.

For the purpose of these experiments we select a sample of 1770 face models (280 people) captured under the conditions in Figure 2. During data acquisition no effort was made to control lighting conditions. In order to generate face models at various head orientations, subjects were asked to face reference points positioned roughlyabove and below the camera, but no effort was made to enforce precise orientation.

3D models are aligned to face directly forwards before conversion into 60 by 90 pixel depth map representation. We then take a training set of 300 depth maps (50 people), used to compute the scatter matrices described in section 3. The remaining 1470 depth maps (230 people) are then separated into two disjoint sets of equal size (test set A and test set B). We use test set A to analyse the face-key variance throughout surface space, calculate discriminant weightings (see section 4) and compute the
optimum surface space combinations. This leaves set B as an unseen test set to evaluate the final combined system. Both training and test sets contain subjects of various race, age and gender and nobody is present in both the training and test sets.

Figure 2: Example face models taken from the University of York 3D Face Database

3D Face --> Surface Space Analysis

2010-01-14T04:48:00.000-08:00

In this section we analyse the surface spaces produced when various facial surface representations are used with the fishersurface method. We begin by testing the variety of fishersurface systems introduced by Heseltine et al [1] on test set A, showing the range of error rates produced when using various surface representations (Figure 3). Continuing this line of research we persist with the same surface representations, referring the reader to previous work [1, 9] for implementation details, while in this
paper we focus on the effect and methodologies of combining multiple systems, rather than the surface representations themselves. Figure 3 clearly shows the choice of surface representation has a significant impact on the effectiveness of the fishersurface approach, with horizontal gradient
representations providing the lowest EER (point at which false acceptance rate equals
false rejection rate).

However, the superiority of the horizontal gradient representations does not suggest that the vertical gradient and curvature representations are no use whatsoever. Although discriminatory information provided by these representations may not be as robust and distinguishing, they may contain a degree of information not available in horizontal gradients and could therefore still make a positive contribution to a combined surface space. We measure the discriminating ability of surface space dimensions by applying Fisher’s Linear Discriminant (FLD) (as used by Gordon [14]) to individual components
(single dimensions) of each surface space. We calculate the discriminant dn, describing
the discriminating power of a given dimension n, between c people in test set A.

Where _i is the set of all class i face-key vector elements in dimension n, and m and mi the mean and class mean of nth dimension elements in test set A. Applying equation 3 to the assortment of surface space systems listed in Figure 3, we see a wide range of discriminant values across the individual surface space dimensions (Figure 4).

Figure 4: Top ten discriminant values of all fishersurface dimensions

It is clear that although some surface representations do not perform well in the face recognition tests, producing high EERs, some face-key components do contain highly discriminatory information. For example, we see that the min and max curvature representations contain one dimension with a higher discriminant than any horizontal gradient and curve type dimension, yet the EERs are significantly higher. We hypothesise that the reason for these highly discriminating anomalies, in an otherwise ineffective subspace, is that a certain surface representation may be particularly suited to a single discriminating factor, such as nose shape or jaw structure, but is not effective when used as a more general classifier. Therefore, if we were able to isolate these few useful qualities from the more specialised subspaces, they could be used to make a positive contribution to a generally more effective surface space, reducing error rates further.