Catálogo de publicaciones - libros

The need to add semantic information to web-accessible services has created a growing research activity in this area. Standard initiatives such as OWL-S and WSDL enable the automation of discovery, composition and execution of semantic web services, i.e. they create a Semantic Web, such that computer programs or agents can implement an open, reliable, large-scale dynamic network of Web Services. This paper presents the research on agent technology development for context-aware execution of semantic web services, more specifically, the development of the Service Execution Agent (SEA). SEA uses context information to adapt the semantic web services execution process to a specific situation, thus improving its effectiveness and providing a faster and better service to its clients. Preliminary results show that context-awareness (e.g., the introduction of context information) in a service execution environment can speed up the execution process, in spite of the overhead that it is introduced by the agents’ communication and processing of context information.

Recent advances in service-oriented frameworks and semantic Web technologies have enabled software agents to discover and invoke resources over large distributed systems, in order to meet their high-level objectives. However, most work has failed to acknowledge that such systems are complex and dynamic multi-agent systems, where service providers act autonomously and follow their own decision-making procedures. Hence, the behaviour of these providers is inherently uncertain — services may fail or take uncertain amounts of time to complete. In this work, we address this uncertainty and take an agent-oriented approach to the problem of provisioning service providers for the constituent tasks of abstract workflows. Specifically, we describe an algorithm that uses redundancy to deal with unreliable providers, and we demonstrate that it achieves an 8-14% improvement in average utility over previous work, while performing up to 6 times as well as approaches that do not consider service uncertainty. We also show that our algorithm performs well in the presence of inaccurate service performance information.

This paper contributes to a line of research that aims to apply agent-oriented techniques in the field of service-oriented computing. In particular, we propose to use goal-oriented techniques from the field of cognitive agent programming for service orchestration. The advantage of using an explicit representation of goals in programming languages is the flexibility in handling failure that goals provide. Moreover, goals have a close correspondence with declarative descriptions as used in the context of semantic web services. This paper now presents first steps towards the definition of a goal-based orchestration language that makes use of semantic matchmaking. The orchestration language we propose and its semantics are formally defined and analyzed, using operational semantics.

The Internet has emerged as a dynamic service-centered environment. How to combine several individual services to provide value-added services is an ongoing research challenge, mainly because dynamic service composition cannot be accomplished easily and the users’ intentions regarding service interconnection have to be anticipated by the service developer. To overcome the drawbacks of developer-centric service composition, we propose an approach to user-initiated dynamic service interconnection characterized by a high degree of usability. We outline a solution for semantic interconnection of two or more services, which provides information that would not be available by using a single service. Based on various interconnection types, we have developed an architecture for user-initiated semantic service interconnection utilizing the planning and negotiation capabilities of intelligent agents. As proof of concept, we have implemented a Web 2.0-based service suite consisting of various individual entertainment services, which assist users in planning their leisure time.

Service Oriented Architecture (SOA) is a compelling topic in Service-Oriented Computing (SOC) paradigm nowadays, as many requirements come from inter- and intra- enterprise service composition. However, as one of the most significant principles of service orientation, service autonomy, has not been addressed systematically. In this paper, we propose a feasible solution for service autonomy through analyzing its intrinsic characteristics. Firstly, from the service lifecycle management point of view, a three layer architecture of service autonomy is designed, based on which a service agent is built to provide core autonomous service functionalities, including automatic service discovery, proactive service monitoring, decentralized service orchestration, and just-in-time information sharing. Second, XMPP (eXtensible Messaging and Presence Protocol) is employed to construct a lightweight fabric of agents. Finally, three typical use cases of web service composition are used to validate the rationality and feasibility of the proposed solution for service autonomy.

In Service-Oriented MAS middle agents provide different kinds of matchmaking functionalities. If no adequate services are available for a specific request, a planning functionality can be used to build up composite services. In order to take advantage of recent advances in the field of AI planning for this purpose, we propose exploiting organisational information of Service-Oriented MAS to heuristically filter out those services that are probably irrelevant to the planning process. We present a novel framework for service-class based filtering and show how it can be instantiated to a particular MAS domain based on role and interaction ontologies.

In industry, people who design business processes are often different from those designing the technical realization. Also, they generally use different languages, such as BPMN on the one hand and UML on the other. While agents are theoretically suitable for designing and implementing business ideas, multi-agent methodologies are generally not geared towards them. In this paper, we describe the first step of mapping business process diagrams to agent concepts. To this end, we present a graph based representation of BPMN together with structural and semantical analysis methods. These provide the necessary formal grounding for the mapping we have in mind.

This paper proposes a new algorithm of associated topic extraction, which detects related topics in a collection of blog entries referring to a specified topic. It is a partial feature of our product reputation information retrieval service whose aim is to detect product names rather than general terms. The main feature of the algorithm is to evaluate how important a topic is to the collection, according to the popularity of blog entries through Trackbacks and comments. Another feature is to utilize product ontology for topic filtering, which extracts products relevant to or similar to a specified product. The paper also presents a brief evaluation of the algorithm, in comparison with TF-IDF. In respect to the evaluation, it can be concluded that the proposed algorithm can capture users’ impressions of associated topics more accurately than TF-IDF.

The Semantic Web Services Initiative Architecture (SWSA) describes the overall process of semantic service execution in three phases: discovery, engagement and enactment. To accomplish the specified requirements of these phases, it defines a conceptual model which is based on semantic service agents that provide and consume semantic web services and includes architectural and protocol abstractions. In this paper, an MAS infrastructure is defined which fulfills fundamental requirements of SWSA’s conceptual model including all its sub-processes. Based on this infrastructure, requirements of a planner module is identified and has been implemented. The developed planner has the capability of executing plans consisting of special tasks for semantic service agents in a way that is described in SWSA. These special tasks are predefined to accomplish the requirements of SWSA’s sub-processes and they can be reused in real plans of semantic service agents both as is and as specialized according to domain requirements.

The ever-growing number of services on the WWW provides enormous business opportunities. Services can be automatically discovered and invoked, or even be dynamically composed from more simples ones. In this paper we concentrate on the problem of service discovery. Most current approaches base their search on inputs and outputs of the service. Some of them also take into account preconditions and effects, and other parameters that describe the service. We present a new approach that complements existing ones by considering the types of interactions that services can be used in. We present our proposal for a concrete application based on a real-world scenario for emergency assistance in the healthcare domain.