GeekGirlBlogs

How to Handle Negative Reviews

(author unknown) — Sat, 11 Jul 2009 00:31:01 PDT

We all fear bad reviews about our business. Bad reviews can be unfair, misleading, and just plain inaccurate. The temptation might to write a rebuttal review, pretending to be a happy customer. You’re hoping to that your own positive review will shout louder than the bad reviews. But it is illegal to write fake reviews about your [...]

Rogers, HP launch network netbook

Gillian Shaw — Fri, 10 Jul 2009 17:52:00 PDT

Netbooks are topping the popularity charts when it comes to notebook computer sales and Rogers is tapping into the trend with its introduction of the HP Mini 110, 3.5G embedded netbook..

Ready to run on Rogers' 3.5G 7.2 Mbps HSPA network, the netbook also has WiFi, making it easy to slip between connections depending on what's available.

HP launched its new 110 mini lineup last spring. The Rogers/HP 110 combo announced today is likely only the start of a trend that will see mini computers sold just like cell phones. The explosion of netbooks has prompted a dramatic change in offerings.

It was only last spring that I was writing about a little HTC Shift mini computer that connected through the Rogers network but at a whopping cost of $1,700 with a three-year contract and $2,100 with no contract.

At $300 with a two-year wireless data plan, the HP Mini 110 comes at a price point that’s starting to put mobile computing close to the range of a higher end cell phone. Of course it doesn take a calculator to figure out that a two-year data plan, starting at $25 plus added fees brings the real cost much higher. But it follows the cell phone model -- the lower price on the device is the trade-off for being locked into a long term contract.

Like other netbooks, the HP Mini 110 has WiFi. It has a 10.1-inch screen and a keyboard that is 92 per cent of standard notebook PCs.

Other specs:

2.57 pounds or just over a kilogram
one-inch (2.5 cm) thick
Intel Atom processor with up to one GB of memory and a 160 GB hard drive

The drawback? Wireless data rates that start at $25.00, plus system access and other fees for 500 megabytes of data.

Would I buy one?

I think netbooks are the new notebooks. For my computer use, I've ditched the desktop, using a hefty notebook computer as my stay-at-home-or-office machine and using a netbook on the go.

An Internet connection is key and I like the USB wireless modems offered by Rogers, Telus and others. You can buy other netbooks - albeit ones with smaller screens - for close to the price of the Rogers' connected HP Mini 110.

So shop around. Rogers is offering a one-stop-shopping deal with the HP Mini 110 that could appeal to businesses looking to equip staff and for individuals looking for a simple solution. It certainly is that - but it's not the only solution.

The new Rogers/HP netbook is only available at Future Shop and Best Buy.

Exploring My World

wonderwebby — Fri, 10 Jul 2009 17:30:38 PDT

Yesterday I picked up a copy of “How To Be An Explorer Of The World” by Keri Smith. And a small handbag-size journal with a combination of blank pages for drawing and lined pages so I can take lots of notes. This will be fun!

I was reading the introduction and I noticed something. This, from page 5 of her book (thanks to Keri for letting me share these images, because it looks so much better in ‘written in the dark’ handwriting :

Now read the same list again.

Now read it again and think about how you engage with people. Yes, even on Twitter.

* * * * * * *

I’m looking forward to investigating my world over the next couple of months. I might even do some of the explorations with the kids.When my boys play with my camera I get a real insight into how they view the world, and their little explorations. This apparently, is how they see things.

Keri Smith’s book reminds me of the way we grew up, taught to find faces or people in everyday things (one of Keri’s exercises) and encouraged to notice the works of art to be found around us. It’s an approach to looking I hope I can pass onto my own children.

Do you like to explore the everyday? How do you like to capture those moments?

Public SQL Server Immersion Event in Dublin in September

kimberly.nospam@nospam.sqlskills.com (Admin) — Fri, 10 Jul 2009 15:58:00 PDT

Paul and I will be teaching a week-long public Immersion Event in Dublin, September 21-25, in partnership with our good friends at Prodata and Microsoft Ireland.

The class will cover:

Day 1: SQL Server Internals (On-disk structures, index internals, logging, recovery, transaction log architecture)
Day 2: Designing for Performance (data types, table and index partitioning)
Day 3: Indexing for Performance (Access patterns, covering, INCLUDE, indexing strategies)
Day 4: Essential Database Maintenance (data and log files, tempdb, index and statistics maintenance, backup and restore)
Day 5.1: Essential Database Maintenance (consistency checking and disaster recovery)
Day 5.2: SQL Consolidation and Virtualization

This is going to be a great workshop where we combine the best of all our various classes into a superb learning opportunity.

Checkout the registration site for more in-depth details about the content, location, and cost.

Hope to see you there!

Happy caturday from me and Neerav

kcarruthers — Fri, 10 Jul 2009 15:02:12 PDT

and that’s because @Neerav suggested this LOLcat

moar Lolcats and funny pictures

Torchwood’s social critique and the education system

Vero — Fri, 10 Jul 2009 15:05:19 PDT

This week, many of us have been riveted to our TV screens more than usual. I have, certainly.

BBC experimented with a 5-part miniseries of the Doctor Who spin off show Torchwood, called Children of Earth. I’ve been a fan of Torchwood since the first season – while it hasn’t been a flawless show, it’s been interesting to see sci fi themes of a more adult nature (not in that way, you perv. Well, ok sometimes…) be approached.

This miniseries not only looked at the usual “alien invasion from the skies” theme, but also looked at Britain in a dark and disturbing way.

For those who haven’t seen it, here is the issue in a nutshell:

Britain is forcefully approached by “The 456″, an alien lifeform that approached it over 40 years ago. In 1965, the 456 requested that they were given 12 children, assuring Britain that they would disappear forever, never to come back. In 2009, the 456 comes back, this time requesting millions of children – 10% of the entire child population of the world. Otherwise it would destroy the human race entirely.

When faced with no other option than to obey the 456, the British government, UNIT, the American forces and a number of other worldwide governing bodies come to the difficult decision of choosing the children who should be handed over.

After discussions of random lotteries and “one loss per family” to meet the 325,000 children to be taken from the UK, one government member suggests what many have been thinking: Use the school league tables to select the lower ranking schools and rid Britain of the scum.

The blunt suggestion is accepted and buses are driven to the disadvantaged schools, providing the media with a spin story that the children are being taken away for inoculations as a means of protection.

I won’t give away the ending for those who still may not have watched the last episode, but will instead look at this situation. Sure, aliens are unlikely to land in Thames House tomorrow to make such demands but what about that bottom 10% of school kids?

In the real world of here and now, are we failing our youth by accepting that disadvantaged areas of the country must necessarily mean lower ranking schools, poorer grades and children who will grow up to spend their life on the dole? In top schools, children are expected to go on to further education and get good, meaningful jobs. Of course, they have the added benefits of a childhood in an independent fee-based school and the likelihood of parents who are more actively involved in their education. These aside, are we taking away the disadvantaged kids’ changes by setting expectations too low?

In this fictive situation, the government made the decision for these kids that they would never amount to anything and were therefore the best group to sacrifice, for the sake of the other 90%.

I don’t have kids and I certainly don’t have an answer, but it was insightful to see Torchwood broach what is a rather controversial topic in between battling aliens and saving lives.

Traffic in the Cloud, powered by Bing Maps Silverlight and DeepEarth

veblog@soulsolutions.com.au — Fri, 10 Jul 2009 13:55:37 PDT

I’m pleased to announced my project has launched for the Azure #newcloudapp international competition. Its called Traffic in the Cloud and provides a rich interactive location twist on public webcams throughout the world.

So what makes this new and worth checking out? Well apart from the slick DeepZoom Silverlight control (you need another reason?) here is why:

Give context to the camera images, browse by location and see what is happening live around the world.
Sit back and enjoy a tour around the world.
An Azure worker process caches 10 frames of each camera so you can now add some motion to your view even if the source website doesn’t.
Those frames are made into a sprite as recommended by Jose Farjardo which means CPU usage and scalability rocks
You can add your own cameras by signing in with a LiveID and filling out a simple form (Approval is needed before it goes live)
All the controls used are available open source from the DeepEarth project on Codeplex.
The image pins use PowerLaw scaling automatically deploying into the camera sprite animation based on Zoomlevel and being in your current view to give a slick experience.

Why run in Azure, couldn’t this just be hosted anywhere?

In short no, this application has the potential to scale to host every public webcam in the world, or it could go nowhere. Only a cloud solution that has the ability to scale beyond the limits of a single server and even a single web farm while only requiring you to consume what you now can allow this. The components of the application are:

Silverlight UI. This file is downloaded and executed on the client allowing the rich interactivity to scale beyond the limits of the hosting server.
Bing Maps for Enterprise serves the map data from its Content Delivery Network around the globe giving you the best imagery and experience with no impact on the hosting server.
The WCF service providing the locations and metadata of the camera is hosted in an Azure Web Role with no state, we can add as many of these roles as we need.
The webcam images themselves are polled once and cached as a sprite image in Azure Blob storage allowing us to directly reference the images on the web.
The webcam metadata is stored in an Azure Table, one camera per row.
The polling service is an Azure Worker Role and this is where the smart part of this application lies. Again we can add as many workers as we need.

How do I add my camera?

Visit: http://tc.soulsolutions.com.au/add.aspx

You will need to sign in using your existing LiveID or make a new one. All we get when you log in is a GUID to identify you, that’s all. We use this to let you manage your webcams and later we could add new features just for you. For example, a personal tour or embed link of just your cameras.

Camera Image URL. This is the full image URL of the actual webcam image, we only only support images. The program doesn’t have browser cache issues so no need for timestamp parameters.
Source Webpage URL. Give credit for the source of the webcam so we can link back to them for users wanting to know more.
Title of Camera.
Description.
Latitude (Decimal Degrees). Why not use my Location Chooser if you don’t know your GPS co-ordinates?
Longitude (Decimal Degrees).
Heading (Degrees). North is 0, East is 90, South is 180 and West is 270. When we have the full power of Silverlight3 perspective 3D we can give an even better experience here.
Refresh Frequency of camera (seconds). Typically 60 seconds.
Total Frames to replay. Typically 10, @60 seconds that will give 10min snapshot.
Height of image (pixels). As sometimes the cameras go offline and show a different sized image we need this specified.
Width of image (pixels). We should create a little helper for this soon however.

When you save it will be stored in your dropdown of cameras but won’t appear on the map straight away. One of our Moderators will need to review the settings you provided and set it to approved. This normally takes a few hours at most. If you edit an approved camera it will also be taken offline and again moderated. We appreciate your patience and I’m sure you understand we don’t want this service abused.

How about some more information into the actual code behind all this?

The Azure Worker Role

An Azure Worker Role is essentially a thread looping forever. You have one implementation of your logic and many, many instances as required. The normal communication channel to distribute the work is an Azure Message Queue. Typically you add stuff to be done to the queue, the hungry workers get them and process them as fast as they can. If your queue gets large you need to add more workers. Importantly the architecture behind Azure allows workers to die or be added at any time, if the message they were processing isn’t completed in satisfactory time it reappears on the queue. Additionally you can’t rely on the Table Storage for synchronising workers as updates can take some time to propagate through the replicated storage.

Now in this application we are working with time. We want a camera to be polled every XX seconds. We don’t want to complicate things with multiple queues or extra tables. I was stumped until I sat down with Joseph Cooney, Bronwen Zande and Joel Pobar and explained the problem over laksa. The solution is quite elegant:

A single queue of all image jobs to be processed, a worker is both a consumer and a producer.

Essentially the worker takes the job off the queue, processes it and then puts the next job on the queue before confirming it has completed the original job. Each job contains a timestamp for when the job should be executed, if it is taken off the queue too early the worker process puts it back. The trick to working out your capacity is no longer how many jobs are on the queue (as this will roughly equal the total number of webcams) but rather the desired processing time versus the actual time an image was processed.

Here is the code:

while (true)
{
    try
    {
        Message msg = imagequeue.GetMessage(Constants.SecondsToExecuteJob);
        if (msg != null)
        {
            var newjob = new ImageJob(msg.ContentAsBytes());
            if (newjob.TimeStamp.CompareTo(DateTime.Now) < 0)
            {
                //update timestamp
                newjob.TimeStamp = DateTime.Now.AddSeconds(newjob.RefreshSeconds);

                //process
                processImage(newjob, container);
            }
            //remove since we have completed successfully
            imagequeue.DeleteMessage(msg);
            //and put back onto the queue
            imagequeue.PutMessage(new Message(newjob.ToXML()));
        }
        else
        {
            Thread.Sleep(1000);
        }
    }
    catch (Exception e)
    {
        RoleManager.WriteToLog(Constants.Critical,
                               string.Format("Exception when processing queue item. Message: '{0}'",
                                             e.Message));
    }
}

Cached Sprite

The idea of this application is to provide an improved experience and features by combining new technology with aggregated data. The webcam images remain the property of the source, we don’t want to store these images and run into legal issues, instead we cache just the last XX images in a single publically addressable image sprite. These sprites use incredibly low cpu usage when animated in Silverlight, I tested 10 of these running at 1-2% cpu for the whole Silverlight application. I have to thank Jose Farjardo who suggested this in his remix Australia talk last month. This is the code I used:

private void Begin()
{
    var element = new Rectangle
                      {
                          Width = Width,
                          Height = Height
                      };

    var spriteSheet = new ImageBrush
                          {
                              Stretch = Stretch.None,
                              AlignmentX = AlignmentX.Left,
                              AlignmentY = AlignmentY.Top
                          };

    var sprite_sheet_position = new TranslateTransform();
    spriteSheet.Transform = sprite_sheet_position;
    spriteSheet.ImageSource = ImageSource;

    element.Fill = spriteSheet;

    var sprite_anim = new DoubleAnimationUsingKeyFrames();
    for (int i = 0; i < Frames; i++)
    {
        var frame_span = new TimeSpan(0, 0, 0, 0, i*MilliSecondsPerFrame);
        sprite_anim.KeyFrames.Add(new DiscreteDoubleKeyFrame
                                      {
                                          Value = (-Width*((Frames-i)-1)),
                                          KeyTime = KeyTime.FromTimeSpan(frame_span)
                                      });
    }

    sb = new Storyboard {RepeatBehavior = RepeatBehavior.Forever};
    sb.Children.Add(sprite_anim);
    Storyboard.SetTarget(sprite_anim, sprite_sheet_position);
    Storyboard.SetTargetProperty(sprite_anim,
                                 new PropertyPath(TranslateTransform.XProperty));
    sb.Begin();

    LayoutRoot.Children.Add(element);
}

DeepEarth

Regular readers of my blog know we have been working with Silverlight DeepZoom and mapping since the dawn of time (Mix2008) and have had a great many people contribute to the project on codeplex. The DeepEarth project has evolved into a toolkit of Silverlight controls and components for mapping. With the released of the Bing Maps Silverlight CTP we have been busy make our controls compatible, extensible and blendable. Lets take a look at the controls used in this application and how you can use them in your application as well.

Navigation Control

http://deepearth.codeplex.com/Wiki/View.aspx?title=Navigation%20Panel

Custom navigation control with pan and zoom controls and a panel for custom functionality, simple add what content you'd like to have on the horizontal arm inside a panel as a child element.

<n:NavigationPanel x:Name="navpanel" MapName="map" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="8,8,8,8" >
    <StackPanel Orientation="Horizontal">
        <Button x:Name="btnPlay" Click="btnPlay_Click"  ToolTipService.ToolTip="Play" Style="{StaticResource StandardButton}" Margin="4,8,4,8">
            <Image Source="Resources/play.png" Width="24" Height="24" />
        Button>
        <Button x:Name="btnPause" Click="btnPause_Click" Visibility="Collapsed" ToolTipService.ToolTip="Pause" Style="{StaticResource StandardButton}" Margin="4,8,4,8">
            <Image Source="Resources/pause.png" Width="24" Height="24" />
        Button>
        <Button x:Name="btnAdd" Click="btnAdd_Click" ToolTipService.ToolTip="Add a camera" Style="{StaticResource StandardButton}" Margin="4,8,4,8">
            <Image Source="Resources/plus.png" Width="24" Height="24" />
        Button>
        <Button x:Name="btnAbout" Click="btnAbout_Click" ToolTipService.ToolTip="About this application" Style="{StaticResource StandardButton}" Margin="4,8,4,8">
            <Image Source="Resources/info.png" Width="24" Height="24" />
        Button>
    StackPanel>
n:NavigationPanel>

MiniMap

http://deepearth.codeplex.com/Wiki/View.aspx?title=Mini%20Map%20Panel

Second Map control to provide overview location of main map and full navigation. Brian from Earthware authored the first version here.

<mm:MiniMap Name="minimap" MapName="map" HorizontalAlignment="Right" VerticalAlignment="Top" />

Coordinate Panel

http://deepearth.codeplex.com/Wiki/View.aspx?title=Coordinate%20Panel

The coordinate panel displays current coordinate information for the mouse position.

<c:CoordinatePanel x:Name="coord" MapName="map" HorizontalAlignment="Right" VerticalAlignment="Bottom" Margin="8,8,8,8" />

Scale Panel

http://deepearth.codeplex.com/Wiki/View.aspx?title=Scale%20Panel

Information Panel showing the current scale of the map.

<s:ScalePanel x:Name="scalepanel" MapName="map" HorizontalAlignment="Right" VerticalAlignment="Bottom" Margin="8,8,8,41" />

Persistent State

http://deepearth.codeplex.com/Wiki/View.aspx?title=Persisted%20State%20Control

Non visual control to maintain the users state between sessions. Uses the Isolated Storage in Silverlight to store a serialized object contain view and mode values.

DeepEarth Logo

http://deepearth.codeplex.com/Wiki/View.aspx?title=DeepEarth%20Logo%20Control

A simple helper control to easily add the most current DeepEarth logo and link to your application in support of this project.

<l:Logo x:Name="logo" HorizontalAlignment="Left" VerticalAlignment="Bottom" Margin="80,8,8,8" />

Vote for Traffic in the Cloud!

If you like the application then give it your vote over at http://www.newcloudapp.com/vote.aspx

Its under John OBrien, about half way down the list of other cool apps.

Future Enhancements

What would you like to see? let me know in the comments, here are my ideas in no specific order.

Location chooser on the add page powered by Bing maps, rather then having to enter your lat/long and also to double check and adjust (fine tune)
Image URL validation, show the image you have supplied and also automatically fill out the height and width.
Links overlaid on the sprite to link back to the original source, plus permalink options / embed links etc.
Permalink for each camera
~~Tour mode, automatic navigation slideshow around the world~~
Statistics, number of views per camera
View just your cameras on the map, permalink and optimised starting point.
Embed snippet to put the map on your site.
Refresh of sprite within map so you can sit on specific camera
Find control, both general locations and locations with cameras

Silverlight 3 upgrade ~~(when released)~~

perspective 3D to give context to heading of camera
pixel shader effects during transition
refactor popout effect as a behaviour

Workflow 4.0, What's Coming, What's Changed

Kathleen — Fri, 10 Jul 2009 15:07:16 PDT

A few friends have pointed out that my post discussing my disappointment with Workflow 4.0 was somewhere between difficult and incomprehensible if you have no idea what's actually changed. Maurice posted this which gives some additional background.

Update on Interactive Mobile Phones: Sony Ericsson's Android Rachael; HTC Hero

Lynn V. Marentette — Fri, 10 Jul 2009 12:47:29 PDT

Both Sony Ericsson and HTC have built upon Google's Android build to create new "user experiences" for mobile phones. Sony Ericsson Rachael UI Video: Related: "Sony Ericsson "Rachael" Android...

[[ This is a content summary only. Visit my website for full links, other content, and more! ]]

3’ on Blend 3 – #1: The Workspace

katriend — Fri, 10 Jul 2009 13:08:38 PDT

This series will introduce concepts of Expression Blend 3, with a short 3 minute video available on MSDN Chopsticks in Dutch and French. The accompanying blog posts will give some resources or insights.

I was actually planning to do the videos in Dutch and French only (the two main languages in Belgium) but then I just went for it and added a version in English for most of the coming videos, so stay tuned... I’m starting with the workspace and then have a number of videos addressing SketchFlow.

#1: The Expression Blend 3 Workspace

Today we start with video no. 1, which addresses the Workspace, assets pane and saving your own workspaces.

3 minutes on Expression Blend 3 – The Workspace

Dutch
French

Recommended sites

Silverlight team blog: http://team.silverlight.net/
Expression community site: http://expression.microsoft.com/
Download Expression Blend 3 RC: http://www.microsoft.com/expression/products/Blend_Overview.aspx

Silverlight 3: Out-of-Browser Applications

katriend — Fri, 10 Jul 2009 12:46:43 PDT

One of the most awaited and requested features before the release of Silverlight 3 Beta was the ability to run Silverlight applications out of the browser. To be clear, this is not completely out of the browser, since the browser chrome/host is still being used. However, the application can be run directly from the Start menu (or desktop), depending on what the user chose.

As a developer you can configure the application so that it can be installed for out of browser use. Next to out of browser, the application can also run offline but only if your code works in such a way that this is allowed. By that I mean you can work with IsolatedStorage to save some information local and use network detection to check for a network. If your application relies on services or files that are online you can disable working in offline mode (but still enable out of browser).

While this feature has been blogged about with Silverlight 3 there are some notable differences with the Silverlight 3 RTW. First it’s important to note the syntax for the application manifest has been changed.
Silverlight 3 Beta breaking changes: while the Beta version used “<Deployment.ApplicationIdentity>” the RTW version now uses <Deployment.OutOfBrowserSettings>

Sample:

<Deployment.OutOfBrowserSettings>
<OutOfBrowserSettings ShortName="OobDemo Application" 
EnableGPUAcceleration="False" 
ShowInstallMenuItem="True">

…

…</OutOfBrowserSettings>
<Deployment.OutOfBrowserSettings>

The good news is Visual Studio is now giving you an editor to configure the out-of-browser settings.

Choose Silverlight project properties > Check “Enable running applications out of the browser” and click the “Out-of-Browser settings” button.

You might notice Visual Studio will create a separate “OutOfBrowserSettings.xml” file to store the settings. The contents of this file get concatenated with the AppManifest.xml file upon build, which is of course logical. If you need to change any of the settings manually (like the ShowInstallMenuItem), you will need to do this in the OutOfBrowserSettings.xml. Adding these out of browser settings in the App manifest file will result in duplicates.

When I now run this demo application and right-click I have the option to install the Silverlight application. This is the default behavior. You can also hide the display of the Install option in the right-click menu and control this programmatically, for example by adding a button “Install”.

When controlling the installation through your own interface you can use Application.Install to install the application out of browser, however this needs to be triggered by a user action. In the sample below I’m responding to a button click event:

private void Install_Click(object sender, RoutedEventArgs e)
  {
    if (Application.Current.InstallState == 
                 InstallState.NotInstalled)
     {
       Application.Current.Install();
     }
 }

Looking forward to seeing applications make use of this feature, there is one out just as Silverlight 3 is released: it’s Sobees Silverlight Twitter client. Worth checking out (just right-click the app to install locally).

Silverlight 3 is RTW, Expression Blend 3 with SketchFlow is RC – go get them!

katriend — Fri, 10 Jul 2009 12:02:13 PDT

Just nine months after the release of Silverlight 2 in October 2008, the new version is here: Silverlight 3 has been released today!

Next to Silverlight 3 you can also find the RC version of Expression Blend 3, including SketchFlow. This RC version targets Silverlight RTW version so you can start using it already to build Silverlight 3 applications. In this RC release you will also find the first public release of SketchFlow.

Where to get the downloads:

Silverlight 3 runtime – http://www.microsoft.com/silverlight/resources/install.aspx
Developer runtimes: Windows and Mac
Silverlight 3 Tools for Visual Studio 2008 SP1
Silverlight 3 SDK
Expression Blend 3 + SketchFlow RC
Silverlight Toolkit – also updated for Silverlight 3 RTW

Next to Silverlight 3, a new release of .NET RIA Services is also available. Note however that .NET RIA services has not been released (RTW), it is an update to the preview version.

.NET RIA Services – July 2009 Preview

And not to forget Deep Zoom Composer targeting Silverlight 3 is also available. This version includes some new features like slideshow support, links and menus.

Deep Zoom Composer (for Silverlight 3)

So what is new with this Silverlight 3 release? Well, quite an extensive list, just look at this page on the Silverlight community site which has a feature comparison chart. My favorites are: Out-of-browser support, multi-touch support (Silverlight on Windows7), Perspective 3D, BasedOn styles, effects, behaviors, DataForm, etc.

Recommended resources

Enjoy (the light)!

Linked Open Data in a Changing World

Jeni — Fri, 10 Jul 2009 11:54:52 PDT

There’s a big push within the UK government right now, helped along by the appointment of Tim Berners-Lee, to publish their data using Linked Data principles.

One of the challenges is how to publish Linked Data in a world that sometimes, even frequently, changes. Cool URIs don’t change, but departmental domain names do, as departments are split and merged and rebranded. So the URIs that are minted for things like schools and roads need to be detached from the departments that have responsibility for them, neutralised into general domains such as education.data.gov.uk and transport.data.gov.uk.

But that’s the least of the problems. Because schools and roads themselves don’t remain static either. They are split and merged and rebranded. They are resources that change over time. What should their URIs look like?

Some choices are (more or less) obvious. If we have an identifier for a school such as:

http://education.data.gov.uk/id/school/109812

then if the school is merged, and a new school is created, this URI can redirect (301 Moved Permanently) to the URI for the new school. If the school is shut down, the URI can respond with a 410 Gone.

But what if the school’s name changes? If we have a triple like this:

<http://education.data.gov.uk/id/school/109812>
  ed:name "Broadmoor Primary School" .

that is true up to 1st September 2009, and:

<http://education.data.gov.uk/id/school/109812>
  ed:name "Wildmoor Heath School"

that is true from 1st September 2009? Are there precautions we should be taking to ensure that these URIs will still work — that the statements we make now about the school will remain valid — in the face of these changes?

I can think of two ways of handling this. (But I’m sure there are others.)

Having ‘current’ and ‘dated’ resource URIs, with the ‘current’ one redirecting to an appropriate ‘dated’ one.
Having ‘dated’ document URIs that become named graphs.

Let me flesh these out a bit.

Current and Dated URLs

On the web, it’s a common pattern to have URIs without dates in them meaning the “current” version of the resource, and URIs with dates to be used for versions on particular dates.

So http://education.data.gov.uk/id/school/19081 could be used for the school as it is now, whereas http://education.data.gov.uk/id/school/19081/2008-09-01 is used for the school as it was on 1st September 2008. If you requested http://education.data.gov.uk/id/school/19081 on 1st April 2009 you’d get a 307 Temporary Redirect response pointing you at http://education.data.gov.uk/id/school/19081/2008-09-01, since that was the last date that the school was updated.

In this scheme, the eventual response you’d get on 1st September 2009 would be something like:

<http://education.data.gov.uk/id/school/19081/2009-09-01>
  ed:name "Wildmoor Heath School" ;
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2009-09-01> .

<http://education.data.gov.uk/school/19081/2009-09-01>
  dc:modified "2009-09-01"^^xsd:date ;
  dct:hasVersion <http://education.data.gov.uk/school/19081/2008-09-01> .

and the same request, to http://education.data.gov.uk/id/school/19081, the day before would have given you:

<http://education.data.gov.uk/id/school/19081/2008-09-01>
  ed:name "Broadmoor Primary School" ;
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2008-09-01> .

<http://education.data.gov.uk/school/19081/2008-09-01>
  dc:modified "2008-09-01"^^xsd:date .

I think there could be another set of triples in both graphs about the timeless http://education.data.gov.uk/id/school/19081 and its relationship to the two versions. But I don’t know what relationship should be used between them (dct:hasVersion?).

The benefit of this approach is that the two sets of triples can be combined without the two versions of the school being merged together (although you still have to make sure you pick the most recent version when you’re doing a query).

The downside is that as time goes on and changes pile on changes, you get more and more repeated triples with differently dated subjects, because many of the properties of the school won’t change. It would be possible to define triples about the unddated http://education.data.gov.uk/id/school/19081, but

those are properties on a different resource, and therefore queries won’t automatically access them;
it’s hubristic to think that you can identify what will and won’t change about a school over its lifetime, so I think you’d end up putting all the properties on the dated versions of the resource just to be on the safe side.

Another problem with this approach is that it makes it harder for people to make assertions externally about the resource. If I’m running my own site and want to say something about this school, I could make the statement:

<http://education.data.gov.uk/id/school/19081> my:rating 5 .

but this would apply forevermore. Or I could make the statement:

<http://education.data.gov.uk/id/school/19081/2008-09-01> my:rating 5 .

which would only apply to the school as on 2008-09-01. I would have to keep track of the new versions of the school as they became available, which is a lot of effort.

Using Dated Document URIs

We could use undated identifier URIs but include metadata about the document containing the RDF in that document which indicates its currency. This is along the lines of what is shown in the Linked Data Tutorial.

Under this approach, the identifier URI http://education.data.gov.uk/id/school/19081 would give a 303 See Other redirection. On 1st April 2009, it would redirect to http://education.data.gov.uk/school/19081/2008-09-01 and would return:

<http://education.data.gov.uk/id/school/19081>
  ed:name "Broadmoor Primary School" ;
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2008-09-01> .

<http://education.data.gov.uk/school/19081/2008-09-01>
  dc:modified "2008-09-01"^^xsd:date .

On 1st September 2009, the identifier URI http://education.data.gov.uk/id/school/19081 would redirect to http://education.data.gov.uk/school/19081/2009-09-01 and the RDF returned would include triples like:

<http://education.data.gov.uk/id/school/19081>
  ed:name "Wildmoor Heath School" ;
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2009-09-01> .

<http://education.data.gov.uk/school/19081/2009-09-01>
  dc:modified "2009-09-01"^^xsd:date ;
  dct:hasVersion <http://education.data.gov.uk/school/19081/2008-09-01> .

The data available about the school at any particular time would always be current, and the metadata about that data can indicate when it was last changed.

A Linked-Data-aware triplestore that regularly scraped the site would create named graphs like:

<http://education.data.gov.uk/school/19081/2008-09-01> {
  <http://education.data.gov.uk/id/school/19081>
    ed:name "Broadmoor Primary School" ;
    rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2008-09-01> .

  <http://education.data.gov.uk/school/19081/2008-09-01>
    dc:modified "2008-09-01"^^xsd:date .
}

<http://education.data.gov.uk/school/19081/2009-09-01> {
  <http://education.data.gov.uk/id/school/19081>
    ed:name "Wildmoor Heath School" ;
    rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2009-09-01> .

  <http://education.data.gov.uk/school/19081/2009-09-01>
    dc:modified "2009-09-01"^^xsd:date ;
    dct:hasVersion <http://education.data.gov.uk/school/19081/2008-09-01> .
}

and it would then be possible to use SPARQL to query the graphs either individually or in combination.

What bothers me about this approach is that anything scraping the data needs to understand the interaction between the date of requesting http://education.data.gov.uk/id/school/19081 and the value of dc:modified in the resource linked to through rdfs:isDefinedBy to tell the difference between information that is true and information that was true. A naive aggregator that regularly visited the site could easily end up with just:

<http://education.data.gov.uk/id/school/19081>
  ed:name "Broadmoor Primary School" ;
  ed:name "Wildmoor Heath School" ;
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2009-09-01> 
  rdfs:isDefinedBy <http://education.data.gov.uk/school/19081/2008-09-01> .

<http://education.data.gov.uk/school/19081/2009-09-01>
  dc:modified "2009-09-01"^^xsd:date .

<http://education.data.gov.uk/school/19081/2008-09-01>
  dc:modified "2008-09-01"^^xsd:date .

with no means of telling which name is associated with which modification date.

Aside: What really bothers me about named graphs is that there’s no real standard. The closest is in SPARQL, which standardises how to query over a set of graphs but doesn’t really say how these graphs could be created. There’s nothing that I know of that says that named graphs should be created as I’ve described above. The syntaxes suggested for expressing named graphs are drafts and notes and proposals.

Without standards that define how named graphs should be created and expressed, it’s hard to work out how exactly they should be used.

So: what options have I missed? How should we be publishing Linked Data in a changing world?

Overheard - Distributed denial of service attack

Margaret Rouse — Fri, 10 Jul 2009 08:32:10 PDT

There are a lot of statements being made by people who are not involved in analyzing these attacks, and a lot of inappropriate rhetoric about ‘cyberwar.’

Dave Dittrich as quoted in Latest DDoS attacks extremely unsophisticated, experts say

DDoS attacks were aimed at several U.S. government sites this past week, including sites for the Federal Trade Commission and the U.S. Department of Transportation. The New York Stock Exchange, the Nasdaq electronic exchange, the Washington Post and South Korean government sites were also attacked.

Researchers from the U.S. Computer Emergency Readiness Team (CERT) and the Korea Internet Security Center are busy analyzing the traffic packets and it looks like there might be a “command and control server” out there giving orders to a zombie army. If that’s true, it should be easier to catch whoever is behind the attacks. Hopefully.

Video of The Day: Synesthesia

Melinda — Fri, 10 Jul 2009 07:00:35 PDT

Episode 122: *blue*

Synesthesia is one of those psychological puzzles that amazes me. If you’ve never heard of it before, it’s a “condition” some people have where one type of stimulation evokes the sensation of another. For instance when hearing sounds, you “see” colours.

[Watch on MissGeeky.com]

How do you estimate accurately when you're running an Agile project?

kate@gregcons.com (Kate Gregory) — Thu, 09 Jul 2009 04:38:19 PDT

We have a long running Agile project underway. Every month or so we deliver a new release, then work with the customer to decide what will be in the next release. Unlike many Agile shops, this isn't our only project - we have other small software development projects, mentoring work, and so on that take up about two thirds of the team's time, leaving one third for this project. What's more, we do this as a little fixed bid project every month, and both my bottom line and the customer are happy with the cost of each release. The key to that, of course, is accurate estimation of the effort in each iteration.

In some ways we have it easy now. The client has working code, and each month all we need to estimate are the changes and additions to that code. But how would it be if we were starting from nothing and planning to build a whole big system over the course of a year or so, for someone who wanted a fixed cost up front and a reasonably complete list of features to be delivered for that cost? Stephen Forte gave a talk recently on just that topic. Plenty of good ideas and a fun listen.

Kate

Practical Architecture

Stephen.Ibaraki — Fri, 10 Jul 2009 11:44:00 PDT

Have a good look at this article by Matt Valentine for some great insights. Matt has over 15 years of experience in architecting and delivering application, database, Web, and transaction systems solutions with major corporations, including AT&T, IBM, ATG, and Microsoft:
http://msdn.microsoft.com/en-us/architecture/aa902620.aspx

“Today’s turbulent business climate creates interesting challenges for architects who are responsible for reducing costs and delivering new capabilities. A practical approach to architecture focuses on:
- Balancing business, technology, and user goals with the goal of delivering near-term revenue and efficiency gains.
- Taking a holistic approach that reduces the complexity of how infrastructure, applications, and tools work together to support critical business applications.”

Contents
Navigating the Storm
Business Goals
Technology Goals
Infrastructure
User Goals
Build Relationships
Create Fans
Practical Architecture
Creating New Efficiencies to Reduce Costs
Finding New Opportunities to Grow the Business
Helping All Users Increase Productivity
Connecting People and Teams
Team-Based Application Development

Cheers,
Stephen Ibaraki

TV Preview: Day One

Melinda — Fri, 10 Jul 2009 04:00:50 PDT

This might actually be a good year for sci-fi. I had heard about NBC’s new show Day One, but it sounded a little bit similar to Jericho. A global disaster, a group of people banding struggling to survive together; it didn’t seem that interesting. But now the first trailer has come out, and it’s got me intrigued.

Here’s the description from NBC:

In the aftermath of a global event that devastates the world’s infrastructures, a small band of survivors strives to rebuild society and unravel the mysteries of why the event took place and what the future has in store. Told from the point of view of an eclectic group of neighbors in a Van Nuys, California apartment building, this journey of survival will show us that hope is found in the smallest of victories and heroes are born every day.

And the trailer:

[Watch on MissGeeky.com]

I’m not too sure about the CGI (but maybe a higher res video would show it better), but the story has got me curious. It’s an alien attack, right? Those weird pillar thingies can’t be man-made. Plus what’s with the whole “I chose each and every one of you”; there’s definitely something more behind that. It somehow seems very reminiscent to The Stand, a Stephen King mini-series from a couple of years ago.

What do you think? Worth watching?

I'm a VB

kate@gregcons.com (Kate Gregory) — Tue, 07 Jul 2009 04:31:52 PDT

I do a lot of work in VB, though I am a C++ MVP not a VB one. This year at the MVP Summit many of the VB MVPs did short interviews with Beth Massi about how they got started and what they do in VB. Get to know some of these folks a little better. I spotted Julie Lerman, Rob Windsor, Ken Getz, Deborah Kurata, Daron Yondem, Jackie Goldstein, and even a thirteen year old! It's a mix of video interviews and text ones, and a very small time committment.

Kate

What Have You Missed On .51?

ubergeeke — Thu, 09 Jul 2009 23:10:54 PDT

There’s quite a bit going on in Ubergeeke’s Lair, but while I draft the posts of all the happenings, let me point the way to a few things you may have missed.

Check out a few posts in engineering, and women in engineering in particular.
Looking to expand your tool kit? Check out these posts.
Want to learn more about Linux? DotFiveOne has plenty of information for you!
Are you all caught up on DotFiveOne interviews?

Looking for something else? Check out the tag cloud on the right sidebar. (And if you’re looking for something that’s not there, email ubergeeke@dotfiveone.com and let me know what’s missing!)

Tomorrow, we return to our regularly scheduled programming - more info about what geeky women are doing right now!