Kau's notes

PhD Cartoon collection.

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sat, 19 Sep 2009 14:42:00 +0000

Found a nice source of cartoons related to higher studies. :-)
Listing a couple of my favs.

Drools 5.0 and business process modeling flexibility

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Thu, 20 Aug 2009 04:26:00 +0000

The rules and workflows are considered to be two different paradigms for business process modeling[1]. Although there are some approaches[2, 3] that attempted combine the advantages of both rule driven and workflow driven business process modeling, the Drools 5.0 combined the advantage of both paradigms as a commercial product.

Earlier the drools modeling considered rules (conditions and actions) as first class citizens. The drools engine allows rules to be specified using the drools language or in xml to be interpreted by the rule processor. This is now provided as the Drools Expert. The java program that integrates the rules engine can pass java objects as facts in to the engine to be evaluated against a rule, or a group of rules. But now with the Drools Flow[4], the processes (better say workflows) are too considered as first class citizens (entities). Also earlier there is no notion of events. The events, such as exceptions, alerts should be handled by the (Java) program. Upon an event the program fires rules. But now with the Drools Fusion [5]the events too are considered first class entities that can be modeled along with processes and the rules. (Here I use the same terminology in the drools documentation. However it should be noted that their use of processes are very similar to the meaning of workflow in other literature. Also when they refer rules it seems they refer to a combination of event and actions). Apart from the above Drools-Govnor allow the users (especially the non-technical lot) to manage the rules using a web interface.

I see following main advantages of this development in drools with Drools Flow and Drools Fusion.

Now it is possible to implement the business logic without being restricted to rule-centric or process-centric modeling approach. Therefore from the design point of view the users can practice the best applicable approach to design different parts of the business logic. Because a flexible process modeling approach will be ended up somewhere in between these two paradigms.

Form the implementation point of view, now the developers have a common API to work with. Earlier the business processes have to be implemented using a different API while rules are specified using Drools (Now Drools Expert). That brought many limitations. For example it wasn’t possible to take decisions in a business process based on an outcome of a rule evaluation. There has to have an intermediary layer to bridge the gap. But now the rules can be used to take decisions on business processes and even assigning the actors to human tasks.

Also, the ability to model complex events using Drools Fusion is a great advancement compared to the earlier versions. In earlier the event handling is done by the java program and which eventually fires a set of rules. However now it is possible to do temporal reasoning of different events (e.g. E1 before E2), use sliding windows both time (e.g. items of last 10 minutes) and length based (e.g. last 10 items) etc.

Moreover the processes, events and rules (Condition, Actions) are all now part of one knowledge base. Thus it is easy to manage the state, share context of a particular process instance. Consequently the process instances can deviate from the pre-defined execution path, for example to handle an exception.

1.R. Lu and S. Sadiq, “A Survey of Comparative Business Process Modeling Approaches,” Business Information Systems, 2007, pp. 82-94.
2.A. Charfi and M. Mezini, “Hybrid web service composition: business processes meet business rules,” Proc. Proceedings of the 2nd international conference on Service oriented computing, ACM, 2004.
3.T. Graml, R. Bracht and M. Spies, “Patterns of business rules to enable agile business processes,” Enterprise Distributed Object Computing Conference, vol. 2, no. 4, 2008, pp. 385-402; DOI http://dx.doi.org/10.1080/17517570802245441.
4. “Drools Flow,” http://jboss.org/drools/drools-flow.html.
5. “Drools Fusion,” http://jboss.org/drools/drools-fusion.html.

Open-source economics

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Wed, 05 Aug 2009 08:27:00 +0000

Sri Lanka - a birds eye view over paradise island

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Tue, 09 Jun 2009 07:06:00 +0000

Nice video about SL. :-)
10 minute birds eye view over paradise island

Autonomic computing vs Artificial intelligence

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Tue, 09 Jun 2009 04:38:00 +0000

This article "Looking to nature for smarter software systems" explains the use of autonomic computing in a very simple way highlighting how it is different from Artificial Intelligence.

Tears and smiles..

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Tue, 19 May 2009 08:40:00 +0000

This is a day that Sri Lanka re-writes her history in a new chapter. The myths that were surrounded with the separatism and terrorism are gone with the wind. Who said they are invincible...?
During my whole life what I saw was WAR.
Bombs were frequent and people used to ask "how many are dead?" Just a routine question. If there is a politician involved then there is something special in the news. Otherwise its just another blast.
Irrespective of day or night ambulances were rushing along the Galle Road from Ratmalana military base. That was a sign of renewed fighting. People flocked in front of TVs again to hear the score. Deaths of humans who used to breath like you and me are just numbers. Sometimes villagers have to cremate a sealed off body of a fallen soldier. My friends/relatives had to cut their leaves short as they were called for the duty. Families had to keep their uncertain eyes open until they come back during the next vacation that no one can predict.
We had to think twice before we schedule our work in Colombo. People were suspicious if you carry a bag or suite case. No chance of keeping it on a rack or under a seat. Buses were randomly stopped at check points. We had to walk through lines with our identity cards ready and wait for the inspection. Men, Women, Elderly and Children alike.
Large amount of money spent on WAR. Military vehicles scrolled along half made dusty roads while the children studying in open class rooms, waving their hands to soldiers.
Without any prior notice roads were closed in the city for VIPs passing by. You have to wait for hours in a bus packed with exhausted commuters. Sweating, cursing, hungry and angry.
This was the life of our generation. If you feel uncomfortable hearing my story, being a Sinhalese, lived in a Suburb of Colombo, you should never hear what a Tamil friend in my age have to say.
Those who preach us to negotiate with the world's most ruthless terrorist organization, never gone through the trauma we gone through for three decades. Those who are trying to satisfy Tamil diaspora just because of few votes, may they lose every election before they rot in hell. Those who put ridiculous conditions, just to give us a "loan", please keep it to yourself. After all we have to pay it back one day.
My heart goes for those families who are now displaced and are living in camps. Remind me the Tsunami in 2004. May they find their way back soon and start rebuilding their life. The worst is over. Its time to move on. No more bullets but ballets. May the politicians at least keep their personal agendas for 5 more years for themselves and work for the betterment of average Sri Lankans. Especially for the sake of those live in North and East.
Finally I would like to pay my gratitude to our armed forces who fought bravely to give a country that is free of terrorism. You are the best people who knows how awful the war is. Not the NGO "gembos" who preach us about the repercussions of war to get their pockets filled with easy $$$s. And HE the president, defense secy and all those who gave their fullest support to reach the target under the pressure from ignorant West. I salute you Sirs. A job well done. But be safe.
I wish the next generations would never ever go through such an experience. May the tears dry and bring a spreading smile along with peace and prosperity for my people.

Cloud computing presentations

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Fri, 17 Apr 2009 14:14:00 +0000

Ayanthi has published the presentation done by Dr. Sanjiva Weerawarana at the SOA symposium on cloud computing.

I'd like to add this presentation done by Dr. Rajkumar Buyya from the Grids Lab to it. This was presented today at the university and it brought a very interesting discussion.

The presentation discusses the evolution of Cloud Computing and how is it different from other paradigms such as Cluster and Grid. Further it discusses about certain case studies that used the Gridbus middleware.

And some interesting definitions for "Cloud Computing can be found here. [Beware 21 of them]

Workflow management systems. A liability or an asset?

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Thu, 16 Apr 2009 04:33:00 +0000

Today more workflow systems appear to assist the business process management. The usual procedure is to draw a business process as a workflow diagram using a notation such as BPMN which will be converted to a code or more preferably to a process execution language script such as WS-BPEL (aka BPEL4WS).

This works fine until there is a requirement for a change in the process flow. The change can be a permanent one or it can be an ad-hoc one that caters for an exceptional situation. In the first case the process definition is changed which is known as an evolutionary change/adaptation. Where all the future instances of the process definition adhere to the new one. In the case of ad-hoc change only a particular process instance is changed which is known as momentary change thus would not affect the future instantiations.

One solution for this is to include all the possibilities into the process definition. For example BPEL switch statement. But some run time changes cannot be predicted during the design time. And even it could, the plethora of possibilities can make the design a very messy and complicated one.

Thus a running business implementation may have a business process but the frequent ad-hoc change might make it a liability than an asset. Making the stakeholders to by-pass the workflow definition rather than adhering to it. Thus it is required to find more flexible ways to design business processes that facilitate the frequent adaptation or change.

This will be my first post on this and will be followed by a series of discussion that will discuss the possible strategies to face the above challenge.

All Marketers are Liars

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Wed, 11 Mar 2009 06:01:00 +0000

Seth Godin speaks at Google...

What is cloud computing?

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Thu, 05 Mar 2009 04:38:00 +0000

This video explains the basics of cloud computing.

Process Aware Information Systems

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Tue, 17 Feb 2009 10:06:00 +0000

During my summer vacation, I started reading the Book "Process Aware Information Systems". The book caught my eye as I was passing a shelf in the library. After reading the preface I decided to have a better look.

The first section gives an overview of PAIS(Process Aware Information Systems) which includes a nice classification of PAIS and the rationale behind it, adding a little bit of history along with techniques and tools too.
Then the book discusses concepts of Workflow Management and modelling, person to person interactions, business to business integration etc.
The section two of the book is more like a reference. That includes UML modelling, petri nets, and event driven process chains. But hard to read continuously though.
The last section discusses more practical methodologies and standards such as XPDL and BPEL. For those who are interested in web services business processes like my self, this is again a good reference. But before reading this section its better to have look at those specifications first and may be started with "Introduction to XYZ..." kind of an article.

A beautiful picture. But a sad story behind.

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Tue, 10 Feb 2009 04:42:00 +0000

[Photo: Hearlad Sun]
Full article

Add yourself to a tree of academics with Academia.edu

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Mon, 09 Feb 2009 03:54:00 +0000

I found this interesting. Facebook for academia...?

http://www.academia.edu/

DNA Computing.. the future wetware

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sat, 07 Feb 2009 03:42:00 +0000

An introductory tutorial is here
This too is interesting to read. But not detailed (and lengthy) as this.

Sinhala lyrics

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Thu, 11 Dec 2008 12:08:00 +0000

Before you get yourself embarrassed during the next party or the picnic ;-)
Find your favourite Sri Lankan songs in Lanka Song Book

ICSOC 2008

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Wed, 26 Nov 2008 11:44:00 +0000

The sixth International Conference on Service Oriented Computing (ICSOC) is to be held from 1st to 5th of December in Sydney, Australia. In parallel to the main conference there is is a PhD symposium (December 1st) that will discuss the approaches, steps, best practices for PhD student that are exploring the Services Oriented Architecture.
After the main conference there is a summer school too. A good opportunity for students living downunder to learn and discuss the latest concepts and technologies in Services Oriented Computing. That will be held in Friday (5th) and Saturday (6th). The complete program is available in the main conference web site here.

Sri Lanka trail guides.

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sat, 22 Nov 2008 02:12:00 +0000

If you are a nature lower and would like to hike in Sri Lanka, have a look at the following web site.
http://www.lakdasun.com
It contains pictures, useful tips and much required trail guides with GPS way points. You may download the trail map and view it on google earth. Thanks Lakdasun team for these useful info. Keep up the good work.

BPEL from CDL

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Thu, 20 Nov 2008 10:32:00 +0000

WS-CDL and WS-BPEL both provide a way to describe how web services should collaborate. But the difference is that WS-CDL gives a global perspective the message exchange whilst the WS-BPEL provides a single participant's perspective.
As some are arguing I do not see a competition between these two specifications. Rather they must co-exist to describe services interactions properly.
Though, WS_CDL is designed to be used in conjunction with the WS-BPEL, one limitation of the WS-CDL specification is that a clear mapping with BPEL is missing. I agree that the intention of WS-CDL is not to be depend on WS=BPEL but there are advantages of having such a clear mapping.

Choreographies can be defined in WS-CDL first by business partners and then generate BPEL process stubs for each party
A party who’s having an internal business processes may need to publish the interface to its processes to attract business partners by generating the choreography. This could be done using a BPEL to CDL mapping.

From the engineering perspective such a mapping could be automated. Also such a defined approach would minimize the inconsistent mappings by different parties coming in to collaboration.
This paper presents how BPEL process definitions are derived from the global WS-CDL model. Authors have done this by defining a set of transformation rules.
For example

Each party participated in CDL choreography a separate BPEL stub is generated
One cdl:relationshipType maps to one bpel:partnerLinkType and the bpel:role with its bpel:portType is generated from the referenced cdl:roleType declaration
Generate separate property files for each cdl:roleType including only those bpel:properties that are relevant for a party.
BPEL basic activities are directly mapped to CDL basic activities
Work units in CDL are related to scopes in BPEL

The complete mapping is available in the section 5.
The paper addresses a much required issue by not altering the existing standards or without introducing new standard, which is a plus point. The approach seems straightforward and not requiring intermediated mapping like in the approach here[4] where the mapping is into Communicating Sequential Processes. Also authors have implemented a prototype of the mapping as a proof of concepts.
Saying that, one limitation of the paper is that there is no reference on how to verify the generated BPEL stubs over the original CDL. Generated stubs may be correct for the given example or could be verified manually for simple scenarios. But it is required to have a formal mechanism to verify more complex scenarios. That is not in future work section too. And the verification need to be integrated to the BPEL stub generation or it should be done after generating BPEL stubs but before the populating them with application logic.
Also it is not clear how the mapping from BPEL processes to CDL is done. Which also an interesting issue (as far as ROAD is concerned ). May be we might be able to complete that part. We can map several processes to a common choreography by projecting them over a ROAD Self Managed Composite. In other words by overlapping several processes we might be able to define the choreography. Syntactical transformations might use the same discussed in the paper. Sure need to think and discuss more about that.

How to pronounce a word like a native?

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sat, 15 Nov 2008 02:01:00 +0000

Ever imagined how to pronounce a word correctly like a native? For example how the word for home in Sinhala language be pronounced in English properly? Is it "Gedara" or "Gethara"? Or something in between "da" and "tha" sounds? Well… now we have the chance to make the correct pronunciation available for non-Sinhala speaking community by recording them via Forvo’s web database.
Forvo’s goal is to collect proper pronunciations of every word in every language on the plant. Sounds bit dotty yeah…? But I think it’s a matter of time. I have already included some words in Sinhalese to the database and will contribute in the future as well.
So if you need to contribute for your language or like to learn how to pronounce a word in another language like French, Spanish or Japanese (as of now 195 languages are supported) properly check this out.

Adaptation categories

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Fri, 14 Nov 2008 13:21:00 +0000

Static Vs Dynamic

The static adaptation can be achieved via logics in the program source code. That’s in the design time where a certain predictions are reflected in program source code and the configuration settings. Dynamic adaptation is the adaptation at runtime. The latter is considered to be more difficult to achieve as it is difficult to predict what are the events are and what the actions on them are. Undoubtedly the latter with a higher research interest.

Manual Vs Automatic

The manual adaptation refers to a sort of adaptation where human intervention is involved. In contrary, the automatic adaptation is where there is no such human involvement. By referring to the existing literature we can see that the more effective adaptation strategies are based on semi-automatic, where at a certain point there is a human involvement but mostly it’s the system itself is adapting to changes. (Especially adaptation of non-functional properties)

Proactive Vs Reactive

The difference here is based on the time of the adaptation occurs with respective to a particular event in the environment. If the adaptation is before the event, then it is proactive adaptation. If the adaptation is after the event then it’s known as reactive adaptation.

Adaptive web processes in a pervasive services oriented environment

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sun, 09 Nov 2008 12:42:00 +0000

Services Oriented Architecture provides different applications to interact in a distributed environment to perform a particular task. The concept of services orientation in software design aimed to achieve the loose coupling of applications from its underlying operating environment. Being a progression of component based software development, Services oriented computing provide interfaces to users (human or software) to utilize a particular resource in a distributed environment.
On the other hand the image of traditional computer is fading away. Mobile /embedded devices claim for a good portion of computing efforts today, with the advancement of electronic technologies. Our car, phone, watch or what ever a device that we can’t picture today, has started to or will become a computing device. This resulted in many researches on Pervasive Computing or Ubiquitous Computing.
The operating conditions in such a pervasive services oriented computing environment are always subjected to change. For example while you are travelling, you mobile phone in your pocket and the car you drive might be doing some message exchanges/queries with applications hosted in nearby restaurants, shops and motels. The operating conditions like the mobile coverage, network bandwidth, types of technologies and even the availability of services can be subjected to frequent changes. The life time of applications is determined by these varying factors of the environment. The survival is always critical. And this calls for self-adaptive software systems.
Studies about adaptable and adaptive software systems have emerged as a major research topic in the past few years. Survival in highly fluctuating environments is a critical requirement for future software systems. Concepts of self-healing, self-configuration, self-optimization and all other self-* buzzwords are popping up in pervasive services oriented software systems. Many frameworks, solutions, techniques are being introduced in the reason past.
It is interesting to study about how business processes adapts to these highly fluctuating environments. Current approaches like BPEL and WS-CDL does not address the adaptation. Although it is possible to identify sort of programmable adaptation, in above approaches, where pre-defined processes are carrying out according to limited "expected" changes, it is not the sort of adaptation that we would be looking for. It is required to define, change choreographies among different business partners at run time in order to ensure smooth continues business processes. Runtime negotiation and establishment/termination of contracts among participating entities are essential part of the adaptation.
My research would be concentrated finding techniques and designs for process adaptation in such a pervasive, services oriented computing environment. Yeah... A diverted lil bit from security:-). Though this is not a really hot topic, I belive that there are more yet to be investigated. Therefore in coming months I'd be concentrating on this.

RESTful PHP Web Services

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sun, 26 Oct 2008 05:32:00 +0000

Samisa has written a book :-)

I'm happy to hear that for two reasons. First, the book fills a gap between PHP web developers and RESTful web services. Second,it is written by someone who really knows ins and outs of the technology.

Given Samisa's expereinces in web services I'd recommend he should write a book on SOAP+PHP as well.

The book is available here

My (neighbor's) question

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Mon, 20 Oct 2008 14:03:00 +0000

Here is my analysis on the current situation between Sri Lanka and India. I'm neither a political analyser nor typically interested about politics(well below the average). So my comments may or may not be valid. Yet I thought it is better to share them as a citizen at this critical moment in Sri Lankan history. Moreover my views are biased. They are biased as I am totally against LTTE terrorism and their ideology.

Current situation in brief

SL military is gaining advantage of the land controlled by LTTE. As a result of that many people (Mostly Tamil) are displaced
Tamilnadu politicians (DMK) are urging Indian Government to intervene the Sri Lankan war. If not they have threatened to withdraw their support to the central, stirring a political storm in India as the general election is just around the corner.
LTTE is a banned terrorist organization in India and the first country to ban the group (even before Sri Lanka). LTTE killed Indian Prime Minister Rajiv Gandhi in 1991 and many IPKF during the period of 1987-1990
SL government is backed by many parties consisting of different communities to finish the LTTE outfit once and for all. Main reasons are
1. LTTE is responsible of killing and chasing of many Sinhalese and Muslims from North and Eastern parts of the island to create their mono ethnic homeland.
2. LTTE have killed many moderate Tamil politicians who do not accept their ideology.
3. LTTE have killed many Sinhalese leaders and potential leaders including former president Ranasinghe Preamadasa
4. LTTE is responsible of destroying many assets of the country. (Katunayake Airport attack, Central Bank)
5. More
Indian government cannot ask from Sri Lanka government to stop the war against LTTE, yet they still need to get the full advantage of the waves of Tamil nationalism in Tamil Nadu, in order to win the GE (At the same time Delhi needs to tame the Tamil nationalism, in order to keep the integrity). On the other hand Pakistan and China is willing to provide unconditional support for the war against terror. These affections are not for the best interest of India in long term. Basically Delhi is in a thick soup.

What SL should do?

Sri Lanka should not treat India as an enemy. The enemy should always be the LTTE.
Sri Lanka should allow India to help the suffering Tamil community. We should not forget that at this moment there are people living under trees. If Tamilnadu politicians are genuine about their appeal, they should help the displaced Tamils not a terrorist organisation. SL government could facilitate this.
Government should convince effectively the Tamil community about their safety (now and post war). Sinhala/Tamil/Muslim political leaders should understand the situation and should fish in troubled water for their short term political interests.
Government should have a mechanism to convince ex-LTTE cadres and Mahaveer families (Those who support the cause and got benefited from LTTE) about their safety too.
Government should provide facilities to those who are displaced due to war. After all we need to make sure that a “child today” is not a “terrorist tomorrow”.
SL government should keep good relationship with international community, not allowing LTTE propaganda to spread lies. Government representatives and diplomats abroad should be more vigilant and active.
Finally SL political parties should unite in this crucial hour. They should throw their personal agendas away. The country should always before the party.

The hypocrisy that cannot be neglected

When LTTE is committing direct attacks on civilians Tamilnadu was in a deep sleep.
Whenever LTTE is militarily powerful and mount attacks on an elected government, Tamilnadu was just blind
Whenever LTTE killed moderate Tamil leaders and torture Tamil civilians, Tamilnadu was deaf.
When tables are turned and Sri Lanka government takes the thing control into its hands (as it aught to do) and LTTE is struggling to survive, Tamilnadu becomes very unconfortable. Despite the wow of LTTE not to allow SLDF to step in tiger control areas, now the Tamil Tigers are pushed towards a defensive war.
Tamilnadu knows very well that India is fighting tooth and nail to keep the Kashmir.

The solution

Still it is too early to say what would be the solution. Seems each party is just continuing what they do. If Sri Lankan government could play their cards carefully and let the Indian governments to handle their internal affairs, then the LTTE would be history. At the same time the government should lay their plans on how to address key issues in every community and pay an especial attention in developing the war torn areas.
It is quite interesting to see how Indian government eat food without burning their fingers. Though an Indian military intervention is far from reality we have to live with South Asian politicians who cannot see beyond the ballot box. Though winning an election is my neighbour's problem...

Sports, Politics and Nitwits

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Wed, 15 Oct 2008 01:04:00 +0000

Blindly following the path of their psychopathic leader, the LTTE goons have staged a stinky protest in Canada during the Twenty20 Cricket series. The best slap over the faces of those pathetic losers, is given by the SL cricket team by winning the series. And for the best of all, the spinner Ajantha Mendis, who was the main target, (just because he is serving in the army) is the man of the series. Too much for the bunch of nitwits who cannot see the difference between sports and politics.

[Photo AP]

Petri nets. An interactive tutorial

noreply@blogger.com (Malinda Kaushalye Kapuruge) — Sat, 27 Sep 2008 02:20:00 +0000

I found a nice interactive tutorial that gives some examples of using Petri nets to model concurrent processes. Here is the famous problem with four philosophers modelled with Petri nets.