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How certain are you?

Posted by daniel on April 6, 2005 at 6:28 AM PDT

Weighting results with the Dempster-Schaffer algorithm

The new project dempster-schaffer is a Java implementation of an algorithm that "allows us to allocate probability-like weights to a set of events in a way that allows statements of ignorance about likelihood of some of the events. From the allocation of weights we get two numbers; the degree to which an event is supported by the evidence (Belief), and the degree to which there is a lack of evidence to the contrary (Plausibility). These two numbers are the basis on which any belief-based decision is made."

How certain a respondent is of their answer is calculated into a weighted average. There has been a second number like this available for weather forecasts for many years. In addition to saying there is a 60% chance of rain, the report could say that they are 80% confident that there is a 60% chance of rain. In the case of weather reports, these additional numbers are not being used because it may confuse more than enlighten people. Where might the dempster-shaffer algorithm be used and would it lead to a result that you would have more confidence in?

Tim Boudreau expresses his enthusiasm for Wicket
in today's href=""> Weblogs . " The folks doing Wicket , possibly the cleanest solution to POJO web apps that I've seen. Wicket is close to release, and the developers could use your help testing it. And even if you can't give them feedback, this framework is really worth a look. The Java and HTML code you write is really as simple as it ought to be! "

Budi Kurniawan writes about a Free Module for More Rapid Struts Development with Tomcat. "This module, which you can download from, is a Tomcat plugin that does not require you to do anything other than copying it to a directory. It works by overriding the WebappLoader, a Tomcat component responsible for loading Web applications. The Context component in Tomcat supports auto-reload. When this feature is enabled, the WebappLoader's modified method gets called regularly. This method checks if any class under WEB-INF/classes or any JAR file under WEB-INF/lib has been changed. If it has, the modified method returns true and the Context is reloaded. "

Donuts? Socks? Read more in Chet Haase's post Smaller is better? What about Faster? It's all a trick. " There's a new survey in town: this one asks for your valuable input to help us set project priorities. "

In Also in
Java Today
, Denis Pilupchuk argues that WS-Security is difficult to deal with in today's programming environments and would be best served by having its own framework, whose requirements he sketched out in Part 1 of his "WS-Security in the Enterprise" series. In WS-Security in the Enterprise, Part 2: The Framework, he begins to assemble the pieces needed for the framework, mapping parts of the standards to Java representations.

The O'Reilly and CollabNet teams that have worked with for the past two years have just helped relaunch dev2dev. Jon Mountjoy, the O'Reilly site editor, has been quietly working on the site since September and now can talk openly about the new features that were unveiled yesterday. CollabNet's Andreas Angelides is hosting the code share component of the site which was unveiled at the end of last year.

In Projects and
, you can Help produce great JAXB/JAX-RPC 2.0 Specs. Check out the early Access implementation of JAXB 2.0 and JAX-RPC 2.0 on, explore the spec and provide feedback.

There is a fresh batch of new projects in the
which includes a game for learning by helping orangutan survive, a Java study group, and the Dempster-Schaffer algorithm.

HLovatt says more about
'fixed' as a complement to 'final'

in today's Forums.
"You can make Immutables test equal to their Value counterparts, see Integer example in the thread you reference. You simply make the Value and Immutable classes inherit from a common base and put the equality test in the common base."

Calum says "It would be really nice to add some form of import package and all descendants, in the same vein as Ant import javax.swing.**; would import all of the swing packages and other packages like javax.swing.event.*, javax.swing.text.*, etc. I think it would make developers lives easier"

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Weighting results with the Dempster-Schaffer algorithm