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Copyright © 2002-2006 short notes. All rights reserved. contact address: email to the editor ISSN 1543-6489
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Tuesday 2003-01-21 Web of Services Dancing with many partners Existing specifications for Web services describe the indivisible units of interactions. It has become clear that taking the next step in the development of Web services will require the ability to compose and describe the relationships between lower-level services. Although differing terminology is used in the industry, such as orchestration, collaboration, coordination, conversations, etc., the terms all share a common characteristic of describing linkages and usage patterns between Web services. For the purpose of this document, and without prejudice, we use the term choreography as a label to denote this space. [...] The Web Services Choreography Working Group, part of the Web Services Activity, is chartered to create the definition of a choreography, language(s) for describing a choreography, as well as the rules for composition of, and interaction among, such choreographed Web services. The language(s) should build upon the foundation of the Web Service Description Language 1.2 (WSDL 1.2). from "Web Services Choreography Working Group Charter" This new W3C working group's importance is obvious: web services industry needs "the ability to compose and describe the relationships between lower-level services". However the term "choreography" is not entirely welcome as it carries deterministic outlook that precludes spontaneity and emergent behavior. permalink Saturday 2002-12-28 Web of Services Semantic Web is harder "When people see web pages, they understand their meaning. When computers see web pages, they get only words and HTML tags. We'd like computers to see meanings as well, so that computer agents could more intelligently process the web. These desires have led to XML, RDF, agent markup languages, and a host of other technologies which attempt to impose more syntax and semantics on the web -- to make life easier for agents. Now, while some of these technologies are certain to see a lot of use (XML), and some of the others may or may well not, I think their proponents all rather miss the mark in believing that the solution lies in mandating standards for semantics. This will fail for several reasons: (i) a lot of the meaning in web pages (as in any communication) derives from the context -- what is referred to in the philosophy of language tradition as pragmatics (ii) semantic needs and usages evolve (like languages) more rapidly than standards (cf. the Académie française), (iii) meaning transfer frequently has to occur across the subcommunities that are currently designing *ML languages, and then all the problems reappear, and the current proposals don't do much to help, and (iv) a lot of the time people won't use the standards -- it's just like how newspaper advertisements rarely contain spec sheets. I will argue that, yes, agents need knowledge, ontologies, etc., to interpret web pages, but the aim necessarily has to be to design agents that can interpret information in context, regardless of the form in which it appears. And for that goal work in natural language processing is of some use, because that field has long been dealing with the uncertain contextual interpretation of ambiguous information. In case the abstract so far hasn't made it obvious: I intend this as more a pontifical than a technical talk, but will discuss a little relevant natural language processing technologies." Christopher Manning's "Information Pragmatics" (in Powerpoint) provides a thoughtful resting place for those chasing Semantic Web. Above abstract is from an earlier version of the talk given at Stanford Database Seminar in 2000. permalink Sunday 2002-12-08 Web of Services Semantic Web is hard Semantic Web is hard. The Resource Description Framework and the Resource Description Framework Schema Specification are supposed to be the foundations of the Semantic Web, in that all other Semantic Web languages are to be layered on top of them. It turns out that such a layering cannot be achieved in a straightforward way. This paper describes the problem with the straightforward layering and lays out several alternative layering possibilities. The benefits and drawbacks of each of these possibilities are presented and analyzed.(Let us refrain from questioning even lower level foundation technologies like XML, URI and Unicode for now.) For details read Peter Patel-Schneider and Dieter Fensel's paper (whose abstract is quoted above) "Layering the Semantic Web: Problems and Directions" (in PDF). permalink Sunday 2002-12-08 Web of Services From web to grid Besides web services, Semantic Web has another technology it can leverage to gain viability: grid computing. Carl Kesselman, one of the leaders of grid computing gave a keynote speech at this year's International Semantic Web Conference titled "The Grid, Grid Services and the Semantic Web: Technologies and Opportunities". Naturally, this merger of the two technologies will be named Semantic Grid. permalink Wednesday 2002-11-27 Web of Services WS = SW Over the last few years Semantic Web has been dovetailing web services. Three examples:
permalink Tuesday 2002-11-26 Web of Services Business process management overview - part 3 DARPA agent markup language or DAML is an application of RDF/XML to write ontologies. DAML-S is a DAML ontology for describing web services or modeling business processes. It aims to support:
See also previous note parts one and two. permalink Tuesday 2002-09-24 Web of Services Sunset for web services A telling paragraph from an old article on connecting Microsoft Office applications with web services reveals why Sun has already lost web services battle. Making implementation of Web services easy for VBA, Visual Basic 6.0, and Visual Studio .NET developers is Microsoft's key tactic to maintain its front-of-the pack status among today's Web service Gang of 2.5. When Sun delivers on its Sun ONE promises and Oracle releases its SOAP-enabled 9i Application Server sometime in 2002, there'll be fierce competition for developer attention between the expanded Gang of Four. I'm betting that new SOAP-based developer toolkits, such as that for Office XP, and on-time release of Visual Studio .NET will make Windows the primary platform for hosting and consuming commercial XML Web services.Unlike IBM, Oracle, Microsoft or other middleware vendors like SAP,BEA, etc, Sun does not have siginificant data "sources" (databases) nor "sinks" (deskstop applications) nor "pipes" (middleware/messaging systems) that produce or consume or move data for web services. For this generation of data-centric web services, Sun provides little heat or light. permalink |
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