Neil's Weblog http://neilmadden.wordpress.com Incoherent ramblings Wed, 23 Sep 2009 09:47:25 +0000 http://wordpress.com/ en hourly 1 http://www.gravatar.com/blavatar/385140162ad8bea3152bb38609d7cff6?s=96&d=http://s.wordpress.com/i/buttonw-com.png Neil's Weblog http://neilmadden.wordpress.com Where is the Web going? http://neilmadden.wordpress.com/2009/08/24/where-is-the-web-going/ http://neilmadden.wordpress.com/2009/08/24/where-is-the-web-going/#comments Mon, 24 Aug 2009 01:46:46 +0000 Neil Madden http://neilmadden.wordpress.com/?p=24 ]]>

I’m becoming increasingly confused about what direction the Web is heading in. More precisely, I’m slightly concerned that the direction the Web is heading in is completely different to the direction in which various researchers believe it is heading in.

In my field of research, I often run into material on the “Semantic Web”. This is supposed to be the vision of where the Web is going: more structured mark-up of information using tags from well-defined, domain-specific vocabularies (so-called “ontologies”). On top of this, we can then build intelligent applications (“agents”) that can draw together information from diverse sources, integrate it, make inferences from it, and generally use this knowledge to act on our behalf. This is a vision I have some sympathy with, although there are clearly huge obstacles to overcome before it becomes anything like a reality. We’re still not sure what logic dialect(s) to base it all on, and that’s just the first step!

But the problems I see with the Semantic Web are not primarily technical. The main problem I see is that the Web is actively evolving in the opposite direction. Just take a look at the HTML 5 (draft) specification. While some lip-service is paid to “semantics” in the introduction, in actual fact the spec moves further away from a declarative, logical language, and instead embraces vacuous tags such as <canvas>. This tag exists solely to provide a context into which to render, procedurally in JavaScript, arbitrary 2D graphics (or 3D graphics with the emerging WebGL standards). While I welcome the attempt to provide an open alternative to technologies such as Flash, I’m not sure that <canvas> really delivers. Indeed, it seems that it suffers many of the same drawbacks of Flash. If the goal was to continue to evolve the more meaningful distinction between different tags, why didn’t they develop a set of specific-purpose tags rather than developing another procedural API? For general graphics, the SVG standard already exists. For charts and graphs, why not introduce a more meaningful chart element, with declarative descriptions of axes, data points, formulae, etc? For example, suppose we wish to plot a 2D chart of the formula y = x2. In the current HTML 5 specification we could “mark-up” this formula as follows:

<!DOCTYPE html>
<html>
<head><title>Test of HTML 5 Canvas Tag</title>
<script>
function point(x, y) { this.x = x; this.y = y; }
function axis(min, max, scale) {
    this.min = min; this.max = max; this.scale = scale;
    this.start = min * scale;
    this.end   = max * scale;
}
function xSquaredChart() {
    var chart = {
        origin:     new point(100, 0),
        xAxis:      new axis(-10, 10, 10),
        yAxis:      new axis(0, 100, 1),
        interval:   0.1
    };
    chart.f = function(x) { return Math.pow(x,2); }
    return chart;
}
function drawChart(ctx, chart) {
    var H = 100;
    var o = chart.origin;

    // Draw the axes
    ctx.fillStyle = "rgb(0,0,200)";
    ctx.fillRect(chart.xAxis.start+o.x, H-o.y, chart.xAxis.end+o.x, -1);
    ctx.fillRect(o.x, chart.yAxis.start, 1, chart.yAxis.end);

    // Plot the data
    ctx.fillStyle = "rgb(200,0,0)";

    for (x = chart.xAxis.min; x <= chart.xAxis.max; x += chart.interval) {
        var y = chart.f(x);
        ctx.fillRect(x * chart.xAxis.scale + chart.origin.x,
                     H - (y * chart.yAxis.scale + chart.origin.y),
                     1, 1);
    }
}
function draw() {
    var chart = xSquaredChart();
    var canvas = document.getElementById("canvas");
    if (canvas.getContext) {
        var ctx = canvas.getContext('2d');
        drawChart(ctx, chart);
    }
}
</script>
</head>
<body onload="draw();">
    <canvas id="canvas" width="200" height="100">A canvas should be here.</canvas>
</body>
</html>

If you try this out in a modern browser such as Firefox or Safari, that supports the canvas tag, you should indeed see a plot of the formula for values of x between -10 and 10. My point is not so much about the length of code needed to plot this simple function—indeed, I have deliberately made the code longer than it needs to be for generality—but more the total opacity of its purpose or meaning. The best we can hope for is that libraries become available for such common tasks, and that authors take the time to also supply marked-up comments and captions that identify that it is a chart and what it is a chart of. Consider a hypothetical alternative if HTML 5 directly supported tags for marking up charts:

<chart id="x-squared" type="line">
  <axis id="x">
    <range from="-10" to="10" step="0.1"/>
    <legend>x</legend>
  </axis>
  <axis id="y">
    <formula>y = x^2</formula>
    <legend>x<sup>2</sup></legend>
  </axis>
  <caption>Plot of x<sup>2</sup>.</caption>
</chart>

The formula element could be specified in MathML content tags or even in JavaScript. Explicit data points could be given with a datum tag supporting error bars and other features. The browser can add all kinds of nifty features, such as the ability to edit data or change ranges on the chart and automatically display the new values, like a spreadsheet. However, the main point is that the mark-up is much clearer, and more importantly, its purpose is easily extracted by automated tools. Other uses of the canvas tag could also be handled by special-purpose tags, such as animation, presentation slides, logos, simulations and even games.

At this point you may be thinking to yourself: OK, but surely you can’t cover every possible use of the canvas tag with special purpose tags? Indeed, you probably can’t. That doesn’t mean that we should try, though. By including special-purpose tags alongside the canvas tag we can encourage people to use them when they fit, and only resort to procedural APIs when all else fails. After all, custom tags should be much simpler to use, more maintainable and readable, and offer the possibility of much more efficient implementations within the browser rather than in JavaScript. Another much more powerful alternative also exists: an ability to define your own custom tags and tag-views. A further post will expand on this topic soon!

]]> http://neilmadden.wordpress.com/2009/08/24/where-is-the-web-going/feed/ 0 neilmadden SecureCode, ClickSafe etc http://neilmadden.wordpress.com/2009/06/21/securecode-clicksafe-etc/ http://neilmadden.wordpress.com/2009/06/21/securecode-clicksafe-etc/#comments Sun, 21 Jun 2009 15:42:26 +0000 Neil Madden http://neilmadden.wordpress.com/?p=20 ]]>

What is the point of MasterCard SecureCode and friends (Lloyds TSB ClickSafe as I see it)? What extra security does having to remember yet another password actually bring? As far as I can tell, very little, as I continually forget my password (made worse as I am then forbidden from using a previous password) and then answer a few basic “security questions” (all of which you could probably answer within 5 minutes of Googling my name), and am allowed to make the payment anyway. I’ve gone through about 10 passwords in the last year, and now simply enter random gibberish, “secure” in the knowledge that I will just have to remember my date of birth next time. Utter useless rubbish foisted on us by the incompetent banking companies to give a slight appearance of added security but in fact just making online shopping more cumbersome.

Does anyone know how to disable it? The “FAQ” says nothing about opting-out.

]]> http://neilmadden.wordpress.com/2009/06/21/securecode-clicksafe-etc/feed/ 0 neilmadden Aeroplanes and Treadmills http://neilmadden.wordpress.com/2008/09/08/aeroplanes-and-treadmills/ http://neilmadden.wordpress.com/2008/09/08/aeroplanes-and-treadmills/#comments Mon, 08 Sep 2008 14:49:17 +0000 Neil Madden http://neilmadden.wordpress.com/?p=16 ]]>

I came across this ridiculous Internet argument today, via xkcd. I find it both amusing, and worrying, the number of people who insist that the plane will not take off. This is a classic example of what philosophers call a thought experiment, and demonstrates only what most thought experiments demonstrate: that our intuitions about even quite simple phenomena are often very wide of the mark. In this case, the intuition is that a vehicle on a treadmill will not move if the treadmill matches the speed of its wheels. While this is true for vehicles (and people) that get their forward thrust from pushing against the ground, an aeroplane certainly doesn’t. The thrust here comes from the propellers or jet turbines that push against the air. These generate an enormous force backwards, which, as per Newton, generates an equal and opposite force pushing the plane forward. If you draw a diagram and label the force arrows (as in school physics lessons), you will see an enormous forward arrow with the only opposing forces being air resistance and a tiny amount of friction from the wheels. It is a basic law of mechanics that when there is a net force acting on an object in a certain direction, then that object will accelerate in that direction. No amount of fast spinning treadmills can reverse the laws of physics. As others mentioned, the wheels will simply spin faster, as they are acted on by forces both from the aeroplane and the treadmill. The wheels decouple the rest of the plane from this treadmill force, and thus the transferred force is negligible. This is, after all, the entire point of having wheels on a plane, and not for instance just having skis.

]]> http://neilmadden.wordpress.com/2008/09/08/aeroplanes-and-treadmills/feed/ 0 neilmadden Computers and numbers http://neilmadden.wordpress.com/2008/08/07/computers-and-numbers/ http://neilmadden.wordpress.com/2008/08/07/computers-and-numbers/#comments Thu, 07 Aug 2008 11:42:50 +0000 Neil Madden http://neilmadden.wordpress.com/?p=11 ]]>

A pet peeve of mine is the ongoing public misperception that computers are really all about numbers. This is constantly reinforced by the mainstream (and even IT) media. Take, for instance, this quote from a BBC News story today:

The DNS acts as the internet’s address books and helps computers translate the website names people prefer (such as bbc.co.uk) into the numbers computers use (212.58.224.131).

What this quote means to say is “DNS transforms textual domain names (such as bbc.co.uk) into the numeric dotted-form (212.58.224.131) that is used by the Internet Protocol (IP)”. To the actual computer, both of these are just patterns of bits that represent symbols. A numeric interpretation is no more or less convenient for the computer than any other symbolic representation: it’s all just patterns of electrical charge as far as the machine is concerned. The inventors of IP could just as easily have chosen to use a DNS-style address representation. It happens that the sort of symbol shifting that computers do is very good for numerical tasks, and it also happens that we know a lot about how to do things with numbers, and so numbers are useful in a lot of applications of computers. In this case, the numeric form can be compactly represented, and efficiently manipulated. That was an engineering decision, not a fundamental limitation of computers.

My love of computers stems from a fascination with language, logic, and fundamental notions of representation and interpretation. Diving into computing has brought me into contact with all sorts of ideas from philosophy, physics, mathematics, linguistics, psychology, cognitive science, and AI. It saddens me that people miss out on these extraordinarily beautiful ideas because of a persistent belief that its all really about numbers, which puts a lot of people off.

]]> http://neilmadden.wordpress.com/2008/08/07/computers-and-numbers/feed/ 1 neilmadden The Decline of Violence http://neilmadden.wordpress.com/2008/08/06/the-decline-of-violence/ http://neilmadden.wordpress.com/2008/08/06/the-decline-of-violence/#comments Wed, 06 Aug 2008 16:30:00 +0000 Neil Madden http://neilmadden.wordpress.com/?p=8 ]]>

Steven Pinker has an interesting talk on the TED conference website, debunking the idea that we are living in an increasingly violent society. As Pinker shows, over pretty much any timescale you care to look at, violent death rates have been dropped considerably, and we now live in the safest time ever. Fascinating and cheering.

]]> http://neilmadden.wordpress.com/2008/08/06/the-decline-of-violence/feed/ 0 neilmadden 60 Years since The Baby http://neilmadden.wordpress.com/2008/06/21/60-years-since-the-baby/ http://neilmadden.wordpress.com/2008/06/21/60-years-since-the-baby/#comments Sat, 21 Jun 2008 12:48:29 +0000 Neil Madden http://neilmadden.wordpress.com/?p=6 ]]>

Manchester is celebrating the 60th anniversary of the first stored program computer, “The Baby”. A link to this was circulated around the Comp Sci email at Nottingham. A fascinating website. It’s amazing to see how far we’ve come in 60 years, but also how sophisticated those early machines already were.

]]> http://neilmadden.wordpress.com/2008/06/21/60-years-since-the-baby/feed/ 0 neilmadden Hello world! http://neilmadden.wordpress.com/2008/05/18/hello-world/ http://neilmadden.wordpress.com/2008/05/18/hello-world/#comments Sun, 18 May 2008 03:40:03 +0000 Neil Madden ]]>

I thought I’d get myself a blog, separate from my university pages. Hopefully from now on I can use this as a place to put various essays and ideas that I have that are not directly relevant to my academic career. For now, I need to get ready for my trip to Toulouse on Monday, so not much will appear here for a little while.

]]> http://neilmadden.wordpress.com/2008/05/18/hello-world/feed/ 0 neilmadden