Tuesday, April 26, 2005


Nick Russell, Arthur H.M. ter Hofstede, David Edmond
Previous work has identified a number of Workflow Control Patterns and Workflow Data Patterns, which characterize the range of control flow and data constructs that might be encountered when modelling and analysing workflows. In this paper, we describe a series of Workflow Resource Patterns that aim to capture the various ways in which resources are represented and utilized in workflows. By delineating these Patterns in a form that is independent of specific workflow technologies and modelling languages, we are able to provide a comprehensive treatment of the resource perspective and we subsequently use these Patterns as the basis for a detailed comparison of a number of commercially available workflow management systems and business process modelling languages.

Topics Workflow | Patterns

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Table of Contents for v2.0 of my Comparison of C# and Java Language Features 

Dare Obasanjo
Almost four years ago I wrote an article entitled C# from a Java Developer's Perspective which is still one of the most popular comparisons of C# and Java on the Web. The article gets a couple thousand hits a month and I still get email about it from developers thanking me for writing it. Given the amount of changes in Java 1.5/5.0 and C# 2.0 I think the time has come to update this article. Below is my proposed table of contents for the new version.

Topics: Java C#

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A conversation with Michael Rys about SQL Server 

Jon Udell
on uses of XML: The bread-and-butter use cases remain what they have been: acquiring relational data from XML documents, transporting relational data as XML, and publishing relational data as XML. But Rys highlighted two emerging use cases that say interesting things about the way in which XML is bringing more fluidity to data management. The first example is what I'll call "expanding entities" -- that is, entities that are primarily modeled in SQL, but that have fluctuating sets of properties which are more conveniently handled in XML. The second example, Rys says, was a surprise to him. People are serializing CLR object data and storing it in XML columns. Given that Yukon directly supports CLR objects, why do that? Two reasons. First, they're limited to 8K -- that's the boundary, in the database, between normal and large objects. But perhaps more importantly, you have to register your .NET assemblies in the database; it's hard to evolve your objects there; and you can't mix types in a single column. With XML, Rys says, you might register an initial schema, but you can then add more schemas over time, and you can mix document types in a single column.

I find this last point -- on XML's role in the evolution of data -- to be especially interesting. Content management and data management have been converging for some time, but there hasn't been common ground on which practioners of these disciplines could meet. Now that enterprise databases are providing that common ground, we should start seeing all kinds of fruitful collaborations.

Topics: SQL | XML

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Thursday, April 21, 2005

Folksonomies and Paving the Cow Paths 

Peter Merholz
The potential benefits of free tagging should encourage practitioners to address such shortcomings. In looking for a real-world analog, I thought of the foot-worn paths that appear in a landscape over time. Called “desire lines,” these trails demonstrate how a landscape’s users choose to move, which is often not on the paved paths. A smart landscape designer will let wanderers create paths through use, and then pave the emerging walkways, ensuring optimal utility.

Ethnoclassification systems can similarly “emerge.” Once you have a preliminary system in place, you can use the most common tags to develop a controlled vocabulary that truly speaks the users’ language.

Topics: Folksonomy | Tagging | Search | Learning

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Sunday, April 17, 2005

On the Unusual Effectiveness of Logic in Computer Science 

Charles Stewart
The title is derived from Wigner's famous article on The Unreasonable Effectiveness of Mathematics in the Natural Sciences, which was devoted to raising and attempting to answer the important question: why should mathematics have been so useful to natural scientists? With respect to logic, my answer for the effectiveness of LICS is that, while computation is a physical phenomenon, it is a phenomenon that is best understood via powerful abstractions, and the most powerful abstractions we have at the moment are abstractions in mathematical logic, because of the fundamental relationship of Turing completeness to Goedelian incompleteness.

Topics: Logic | Mathematics

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Semantic Steganography 

Sean McGrath
The future of semantic markup is the tunnelling of semantics, unseen, inside harmless looking, presentation-oriented XHTML.

I'm thinking microformats and I'm thinking things like XOXO and HMML and RDDL

Here is the thing: with span and div elements, it is possible to encode any XML instance into a valid XHTML instance. It is a trivial matter to reverse the process to get the explict element-oriented XML back out.

Topics: SematicWeb | XHTML

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A REST Intervention 

Koranteng's Toli
Being able to bookmark places, pages and portlets is fundamental for many reasons beyond simple usabilty. At a first order, you were now able to paste a url in an instant message to co-workers so they could join you and see what you were looking at, at that moment. But also, almost overnight with this feature, many layers of complexity were shed in the portal framework.

Programmability in the web sense was immediately enabled, the portal became a composable platform and we were able to layer the Lotus Workplace offering on top of it. URIs give visibility to intermediaries and so things like caching (where we had cool technologies like Dynacache) were far more easily enabled. Similarly for logging and profiling the portal, we could use the same tools for processing logs as exist for regular web servers. We had new opportunities for pipelining and filter chains (to do transcoding if needed). We had more options for load balancing, we could decide to deal with remote portlets through iframe invocation rather than through complex protocols like WSRP. And so on...

Topics: REST | WebServices

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Friday, April 01, 2005

Ontology is Overrated 

Clay Shirky
Does the world make sense or do we make sense of the world. If you believe that the world makes sense, then anyone who tries to make sense of the world differently from you, is presenting you with a situation that needs to be reconciled formally. Because if you get it wrong, you are getting it wrong about the real world.

If we make sense of the world, if we from a bunch of different points of view are applying some kind of sense to the world, then you don’t privilege one top level version of sense making over the other. What you do instead is try and find ways that the individual sense making can roll up to something which is of value in the aggregate, but you do it without an ontological goal. You do it without a goal of explicitly getting to or even closely matching a perfect view of the world.

So it’s all context dependent and this I think is what were starting to see with del.icio.us and flickr and other systems. Ways of building these systems that doesn't assume that the structured hierarchical categorical systems so often forced on us by the physical system is going to continue. Instead we are dealing with a radical break where rebuilding around the URL and the flexibility of the link, we will get an entirely alternate ...

Topics: Categorization | Ontology | Folksonomy | Meaning

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