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.

/pdf/daml-s-semantic-markup-for-web-services-2bz2kpfwet.pdf

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.

/pdf/qos-aware-middleware-for-web-services-composition-x57gs4mhme.pdf

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.

/pdf/service-oriented-architectures-approaches-technologies-and-1m0bcwz0fm.pdf

Service oriented architectures: approaches, technologies and research issues

Current industry standards for describing Web Services focus on ensuring interoperability across diverse platforms, but do not provide a good foundation for automating the use of Web Services. Representational techniques being developed for the Semantic Web can be used to augment these standards. The resulting Web Service specifications enable the development of software programs that can interpret descriptions of unfamiliar Web Services and then employ those services to satisfy user goals. OWL-S ("OWL for Services") is a set of notations for expressing such specifications, based on the Semantic Web ontology language OWL. It consists of three interrelated parts: a profile ontology, used to describe what the service does; a process ontology and corresponding presentation syntax, used to describe how the service is used; and a grounding ontology, used to describe how to interact with the service. OWL-S can be used to automate a variety of service-related activities involving service discovery, interoperation, and composition. A large body of research on OWL-S has led to the creation of many open-source tools for developing, reasoning about, and dynamically utilizing Web Services.

/pdf/bringing-semantics-to-web-services-with-owl-s-52kxa9d5zi.pdf

Bringing Semantics to Web Services with OWL-S

SRI’s Open Agent Architecture (OAA), a research framework for constructing agent-based systems, makes it possible for software services to be provided through the cooperative efforts of distributed collections of autonomous agents. Communication and cooperation between agents are brokered by one or more facilitators, which are responsible for matching requests, from users and agents, with descriptions of the capabilities of other agents. Thus, it is not generally required that a requester (user or agent) know the identities, locations, or number of other agents involved in satisfying a request. Facilitators are not viewed as centralized controllers, however, but rather as coordinators, as they draw upon knowledge and advice from several different, potentially distributed, sources to guide their delegation choices. OAA is structured so as to minimize the effort involved in creating new agents and “wrapping” legacy applications, written in various languages and operating on various platforms; to encourage the reuse of existing agents; and to allow for dynamism and flexibility in the makeup of agent communities. Distinguishing features of OAA as compared with related work include extreme flexibility in using facilitator-based delegation of complex goals, triggers, and data management requests; agent-based provision of multimodal user interfaces; and built-in support for including the user as a privileged member of the agent community.

The Open Agent Architecture

The present invention provides a Unified Messaging system with an emphasis on ubiquitous access and dynamic presentation of the information and services supported by an agent community. The present invention allows queries across dynamically changing, complex information; shared context and reference resolution among applications; and flexible translation of multimedia data. Utilizing an Open Agent Architecture, the present invention allows a user to receive multiple information types, such as email, voicemail, and multimedia data, utilizing a single user interface, such as a phone. Communication and cooperation between agents are brokered by one or more facilitators, which are responsible for matching requests, from users and agents, with descriptions of the capabilities of other agents. It is not generally required that a user or agent know the identities, locations, or number of other agents involved in satisfying a request, and relatively minimal effort is involved in incorporating new agents and “wrapping” legacy applications. Extreme flexibility is achieved through an architecture organized around the declaration of capabilities by service-providing agents, the construction of arbitrarily complex goals by users and service-requesting agents, and the role of facilitators in delegating and coordinating the satisfaction of these goals, subject to advice and constraints that may accompany them.

Unified messaging methods and systems for communication and cooperation among distributed agents in a computing environment

A key element to realizing the Semantic Web is developing a suitably rich language for encoding and describing Web content. Such a language must have a well defined semantics, be sufficiently expressive to describe the complex interrelationships and constraints between Web objects, and be amenable to automated manipulation and reasoning with acceptable limits on time and resource requirements. A key component of the Semantic Web services vision is the creation of a language for describing Web services. DAML-S is such a language it is a DAML+OIL ontology for describing Web services that a coalition of researchers created with support from DARPA.

/pdf/bringing-semantics-to-web-services-4ua4iu453a.pdf

Bringing semantics to Web services

The design and development of the Open Agent Architecture (OAA) 1 system has focused on providing access to agentbased applications through an intelligent, cooperative, distributed, and multimodal agent-based user interfaces. The current multimodal interface supports a mix of spoken language, handwriting and gesture, and is adaptable to the user’ s preferences, resources and environment. Only the primary user interface agents need run on the local computer, thereby simplifying the task of using a range of applications from a variety of platforms, especially low-powered computers such as Personal Digital Assistants (PDAs). An important consideration in the design of the OAA was to facilitate mix-andmatch: to facilitate the reuse of agents in new and unanticipated applications, and to support rapid prototyping by facilitating the replacement of agents by better versions. The utility of the agents and tools developed as part of this ongoing research project has been demonstrated by their use as infrastructure in unrelated projects.

/pdf/multimodal-user-interfaces-in-the-open-agent-architecture-30sq5voh8q.pdf

David Martin

Papers

Bringing Semantics to Web Services with OWL-S

The Open Agent Architecture

Unified messaging methods and systems for communication and cooperation among distributed agents in a computing environment

Bringing semantics to Web services

Multimodal user interfaces in the Open Agent Architecture