Hridesh Rajan working in Iowa State university, USA, presented the paper "How to Trust Web Services Monitor Executing in an Untrusted Environment?". It was one of the most interesting papers of the whole conference. It proposes adding hardware-based trust verification capabilities to SOA, using TPM - Trusted Platform Module - embedded in the servers' microprocessors (ex. Intel's). Only the trust monitors are bound to the server hardware TPM but not the services executing on that machine. This is an interesting approach to build a TCB - Trusted Computing Base - in a distributed system. However, there has to be a hardware registry of the servers, and a trusted procedure for the distribution of public keys when new servers are added to the infrastructure.
Another very good paper was presented by Gottfried Vossen, from Germany: "Web Service Discovery - Reality Check 2.0". The paper discusses the real world use of Web Service registries, like UDDI. The main conclusion is that UDDI may be interesting in a closed world inside an organization (especially in a single vendor environment - SAP, Microsoft, IBM, ...), but in the Internet, service discovery is mostly a human-centered process: people find out about the service and link directly to its contracts. The Universal Business Registry vision might never come true.
On a side-note, the paper also does a good Web 2.0 overview, highlighting its main principles and differences to Web 1.0.
The paper "ATHENE - An Approach for Modeling Semantic Web Processes over User-friendly and Editable Ontology Models" by Nishant Singh from India, presents a well structured approach to semantic description of services, using a user-driven process, with a three layer model. The users are developers and/or domain experts. The tiers are Meta2-model (object, types and relations), Meta-model (using OWL) and Model. There are also some user-interface abstractions - like notebook - to help the users edit the ontology.
Next, I presented my work "Core mechanisms for Web Services extensions" (in case you don't remember, I'm Miguel Pardal from Portugal's Instituto Superior Técnico). I described the core mechanisms necessary to build Web Services extensions, regardless of the underlying platform. I also mentioned the on-going work to build an extensions engine integrated in a three-layered application framework. In the Q&A, I talked about general-purpose extensions (ones that add some specific funcionality or a WS-standard implementation) and customization extensions (ones that add features to an existing capabilities). A good analogy for WS-extensions are Mozilla Firefox's extensions.
The next presentation was "A Framework for the Requirements Analysis of Service-oriented Workflows" by Jochen Muller, from Germany's University of Kaiserslautern. The paper presents a workflow definition where it is a service and is composed of (stateless) services. The methodology distinguishes between process design and enactment stages of the workflow. The workflows can be long-running, with some instances taking years. The system is focused in the e-Government domain, particularly, in the gov-to-gov interactions. In my opinion, this proposal would benefit from having an explicit account for versioning, in order to have different version workflows running side-by-side.
The final presented paper was "On The Use of Ontology Reconciliation Techniques in SOA" by Patricio de Alencar Silva, from Brazil. This work is about the Semantic Web and its automatic service discovery and binding. The paper acknowledges the fact that semantic heterogeneity is not a computational problem, but a philosophical one. It presents the existing approaches to brigde concept definitions gaps between different organizations and application domains using ontology-based techniques.
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