The Semantic Web should enable greater access not only to content but also to services on the Web. Users and software agents should be able to discover, invoke, compose, and monitor Web resources offering particular services and having particular properties. As part of the DARPA Agent Markup Language program, we have begun to develop an ontology of services, called DAML-S, that will make these functionalities possible. In this paper we describe the overall structure of the ontology, the service profile for advertising services, and the process model for the detailed description of the operation of services. We also compare DAML-S with several industry efforts to define standards for characterizing services on the Web.

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DAML-S: semantic markup for web services

The paradigmatic shift from a Web of manual interactions to a Web of programmatic interactions driven by Web services is creating unprecedented opportunities for the formation of online business-to-business (B2B) collaborations. In particular, the creation of value-added services by composition of existing ones is gaining a significant momentum. Since many available Web services provide overlapping or identical functionality, albeit with different quality of service (QoS), a choice needs to be made to determine which services are to participate in a given composite service. This paper presents a middleware platform which addresses the issue of selecting Web services for the purpose of their composition in a way that maximizes user satisfaction expressed as utility functions over QoS attributes, while satisfying the constraints set by the user and by the structure of the composite service. Two selection approaches are described and compared: one based on local (task-level) selection of services and the other based on global allocation of tasks to services using integer programming.

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QoS-aware middleware for Web services composition

The Web is moving from being a collection of pages toward a collection of services that interoperate through the Internet. The first step toward this interoperation is the location of other services that can help toward the solution of a problem. In this paper we claim that location of web services should be based on the semantic match between a declarative description of the service being sought, and a description of the service being offered. Furthermore, we claim that this match is outside the representation capabilities of registries such as UDDI and languages such as WSDL.We propose a solution based on DAML-S, a DAML-based language for service description, and we show how service capabilities are presented in the Profile section of a DAML-S description and how a semantic match between advertisements and requests is performed.

https://www.cmpe.boun.edu.tr/~pyolum/cmpe596/papers/matchmaking.pdf

Semantic Matching of Web Services Capabilities

JADE (Java Agent Development Framework) is a software framework to make easy the development of multi-agent applications in compliance with the FIPA specifications. JADE can then be considered a middle-ware that implements an efficient agent platform and supports the development of multi agent systems. JADE agent platform tries to keep high the performance of a distributed agent system implemented with the Java language. In particular, its communication architecture tries to offer flexible and efficient messaging, transparently choosing the best transport available and leveraging state-of-the-art distributed object technology embedded within Java runtime environment. JADE uses an agent model and Java implementation that allow good runtime efficiency, software reuse, agent mobility and the realization of different agent architectures.

Developing Multi-Agent Systems with JADE

Service-oriented architectures (SOA) is an emerging approach that addresses the requirements of loosely coupled, standards-based, and protocol- independent distributed computing. Typically business operations running in an SOA comprise a number of invocations of these different components, often in an event-driven or asynchronous fashion that reflects the underlying business process needs. To build an SOA a highly distributable communications and integration backbone is required. This functionality is provided by the Enterprise Service Bus (ESB) that is an integration platform that utilizes Web services standards to support a wide variety of communications patterns over multiple transport protocols and deliver value-added capabilities for SOA applications. This paper reviews technologies and approaches that unify the principles and concepts of SOA with those of event-based programing. The paper also focuses on the ESB and describes a range of functions that are designed to offer a manageable, standards-based SOA backbone that extends middleware functionality throughout by connecting heterogeneous components and systems and offers integration services. Finally, the paper proposes an approach to extend the conventional SOA to cater for essential ESB requirements that include capabilities such as service orchestration, "intelligent" routing, provisioning, integrity and security of message as well as service management. The layers in this extended SOA, in short xSOA, are used to classify research issues and current research activities.

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Service oriented architectures: approaches, technologies and research issues

We give an overview of rules in the Semantic Web Services Language (SWSL) from the viewpoint of directions for standardization. This includes requirements, tasks about services, kinds of knowledge, combining rules with ontologies, suitability of fundamental knowledge representations and desirability of particular expressive features. Note: To Find More about this paper For updated/extended versions of this paper, and additional related material, see http://ebusiness.mit.edu/bgrosof/#SWSLPosnPapForW3RuleWksh starting in earlyor mid-April 2005. 1. Intro to Semantic Web Services Language (SWSL) The promise of Web services and the need for widely accepted standards enabling them are widely recognized, and considerable efforts are underway to define and evolve such standards in the commercial realm. Prominent among these are: Oasis’s UDDI, BPEL4WS, and Web Services Security; and W3C’s WSDL and Choreography Description Language. At the same time, recognition is growing of the need for richer semantic specifications of Web services, based on a comprehensive representational framework that spans the full range of service-related concepts. Because an expressive representation framework permits the specification of many different aspects of services, it can provide a foundation for a broad range of activities, across the Web service lifecycle, while enabling radically more and cheaper reuse of such specification knowledge across those aspects, across applications and organizations, and over the duration of the lifecycle. It can support cheaper, broader, and deeper automation of many service tasks, including: service selection and invocation; translation of message content between heterogeneous interoperating services; service moni-

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Rules in the Semantic Web Services Language (SWSL): An Overview for Standardization Directions.

Over the last decade, research in agent-based systems (ABS) has spawned a multi-faceted field, addressing a broad range of challenges and generating a varied array of technical approaches. Web service technologies, in contrast, have arisen in a more incremental fashion, with more modest aims, although the vision statements associated with Web services sometimes overlap significantly with those of ABS. Work on Semantic Web services aims to provide richer specifications of services, so as to enable fuller, more flexible automation of service provision and use, support the construction of more powerful tools and methodologies, and promote the use of semantically well-founded reasoning about services. This chapter provides an overview of OWL-S, a Semantic Web services ontology, and discusses its connections with work on agent-based systems. We argue that OWL-S takes some significant, although limited, steps towards a foundation for the deployment of agent technologies on the Web.

OWL-S and Agent-Based Systems

There has been a considerable and significant number of researches that looked into the uncertainty and risk of valuation process in various parts of the world, especially in the US and the UK. Early research tended to focus on the tangible methods used by valuers. In recent times, research has concentrated on anticipated risk that could be encountered in carrying out valuations and the way that valuation information is processed. The summary of the previous researches skip over a further latent and potential influence: that of the influence of intangible elements of uncertainty and risk on property valuation and the transaction which might follow The aim of this paper is to examine the effect of intangible elements of uncertainty in property valuation and also to have a thorough understanding of the risk inherent in property valuations. The main research questions that this study seeks to address include: What precisely are intangible elements of uncertainty with regard to valuations? How could intangible elements of uncertainty in property valuation be minimized and dealt with? To what extent do intangible elements of uncertainty affect and influence property valuation? And should there be a general approach of anticipating and forecasting intangible elements of uncertainty in property valuation? A mixture of self-administered questionnaires and in-depth personal interviews were considered most appropriate as data collection instrument for this research due to the advantages derivable from both approaches. Descriptive and inferential statistics will be employed to interpret and explain the associations found among the variables. This is a paper in progress and as such the expected outcomes of the study might suggest that the series of comparable evidence available is the most common factor that will affect a valuation certainty. Risk and uncertainty could be inherent parts of the valuation process as regularly the valuer is unable to identify and price correctly all existing and future influences on the value of the asset. It is recommended that the Royal Institution of Chartered Surveyors (RICS) should build up a standard methodology and approach to uncertainty expression, not only for the valuer’s peace of mind, but in order to offer the most excellent and promising service to the general community. Keywords : Intangible Elements, Property, Risk, Uncertainty and Valuation

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Intangible Elements of Uncertainty in Property Valuation: Theoretical Underpinning

The SPARQL 1.1 Query Language [1] permits patterns inside FILTER expressions using the EXISTS construct, specified by using substitution. Substitution destroys some of the aspects of SPARQL that make it suitable as a data access language. As well, substitution causes problems in the SPARQL algebra and produces counterintuitive results. Fixing the problems with EXISTS is best done with a completely different definition that does not use substitution at all.

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EXISTStential Aspects of SPARQL.

The iterative user interaction approach for data integration proposed by Falconer and Noy can be generalized to consider interactions between integration tools generators that generate potential schema mappings and users or analysis tools analyzers that select the best mapping. Each such selection then provides high-confidence guidance for the next iteration of the integration tool. We have implemented this generalized approach in CogMap, a matching system for both property and instance alignments between heterogeneous data. The generator in CogMap uses the instance alignment from the previous iteration to create high-quality property alignments and presents these alignments and their consequences to the analyzer. Our experiments show that multiple iterations as well as the interplay between instance and property alignment serve to improve the final alignments.

/pdf/cogmap-a-cognitive-support-approach-to-property-and-instance-4y0yhbkpai.pdf

David Martin

Papers

Rules in the Semantic Web Services Language (SWSL): An Overview for Standardization Directions.

OWL-S and Agent-Based Systems

Intangible Elements of Uncertainty in Property Valuation: Theoretical Underpinning

EXISTStential Aspects of SPARQL.

CogMap: A Cognitive Support Approach to Property and Instance Alignment