Paul A. Buhler

Multiagent systems with workflows

Industry and researchers have two different visions for the future of Web services. Industry wants to capitalize on Web service technology to automate business processes via centralized workflow enactment. Researchers are interested in the dynamic composition of Web services. We show how these two visions are points in a continuum and discuss a possible path for bridging the gap between them.

Inside an agent

When we discuss agent-based system construction with software developers or ask students to implement common agent architectures using object-oriented techniques, we find that it is not trivial for them to create an elegant system design from the standard presentation of these architectures in textbooks or research papers. To better communicate our interpretation of popular agent architectures, we draw UML (Unified Modeling Language) diagrams to guide an implementers design. However, before we describe these diagrams, we need to review some basic features of agents. The paper considers an architecture showing a simple agent interacting with an environment. The agent senses its environment, uses what it senses to choose an action, and then performs the action through its effectors. Sensory input can include received messages, and action can be the sending of messages. To construct an agent, we need a more detailed understanding of how it functions. In particular, if we are to build one using conventional object-oriented analysis and design techniques, we should know in what ways an agent is more than just a simple object.

Web Service Discovery and Composition using the Web Service Integration Gateway

In recent years Web services and their associated standards have received an enormous amount of attention. Web services hold the promise of creating a distributed global repository of network addressable units of computation. This repository will undoubtedly generate a disruptive force that will fundamentally change not only the methodologies and techniques used for software construction, but will even challenge our perception of what constitutes a software application. In the future software applications will be increasingly amorphous, dynamically adapting their composition at run-time in response to changes in environmental context and conditions.

Preparing for Service-Oriented Computing: A Composite Design Pattern for Stubless Web Service Invocation

The ability to dynamically bind to Web services at runtime is becoming increasingly important as the era of Service-Oriented Computing (SOC) emerges. With SOC selection and invocation of Web service partners will occur in software at run-time, rather than by software developers at design and compile time. Unfortunately, the marketplace has yet to yield a predominate applications programming interface for the invocation of Web services. This results in software that is deeply ingrained with vendor-specific calls, which is problematic because Web service technology is changing at a rapid pace. In order to leverage the latest developments, code often needs to be heavily refactored to account for changing invocation interfaces. This paper explores the mitigation of this problem through the application of software design patterns.

Trust and persistence [software agents]

We rely on computers to control our power plants and water supplies, our automobiles and transportation systems, and soon our economic and political systems. Increasingly, software agents are enmeshed in these systems, serving as the glue that connects distributed components. Clearly, we need mechanisms to determine whether these agents are trustworthy. What do we need to establish trust? Agents are often characterized by features such as autonomy, sociability, proactiveness, and persistent identity. This latter feature is key in determining trust. When agents operate over an extended period, they can earn a reputation for competence, timeliness, ease of use, and trustworthiness, which is something ephemeral agents cannot do. Along with persistence, we need a reliable way to identify an agent and ensure that its true identity is not concealed. How can we assess an agents trustworthiness? As with other aspects of agents and multiagent systems, we can take our cue from the human domain. Our reputations for trustworthiness are determined and maintained by the people we deal with. Analogously, a software agents reputation will reside within the other agents with whom it interacts. For some agent interactions, such as those involving commerce, agents will simply inherit the reputation of their human owner, sharing, for example, their owners credit rating and financial capability. For other types of interactions, such as those involving information gathering, an agent will determine its own reputation through its efforts at gathering and distilling information. An agent with a reputation for conducting thorough searches will be trusted by other agents wishing to use its Web search results.

A Multiagent Web Service Composition Engine, Revisited

This paper provides an update on our Multiagent Web Service Composition Engine which was entered in the first Web Service Composition Challenge at the EEE-05 conference. This paper explores the rational behind the selection of a multiagent architecture for service composition problems and demonstrates the relevance of interaction based computation. Rather than describing the composition algorithm from an AI reasoning perspective, a description of the service composition agents from an interaction perspective is provided.

Experiences Building a Standards-Based Service Description Repository

Approaches to Web service composition are dependent upon some form of repository to hold service descriptions. Most service composition software relies upon highly-optimized and proprietary formats for representing service descriptions and storing them into a repository. Unlike these approaches, this paper reports on the development and evolution of a standards-based service description repository. The evolutionary aspect of the described service description repository is of interest as it provides insight into the rapidly changing landscape of semantic technologies and tools; from topic maps to triple-spaces. The work described in this paper is contextualized against the backdrop of the Web services challenge an annual software competition which fosters research in the realm of Web service discovery and composition.

Tools and Lessons from a Multiagent Systems’ Class

Abstract We provide a summary of the lessons we have learned after teaching a graduate multiagent systems class over the last six years. The class has used various technologies such as RoboCup (along with our Biter and SoccerBeans tools), NetLogo, JADE, and FIPA-OS. We discuss their advantages and disadvantages. We also discuss our view of the future of multiagent systems. We notice the ongoing separation of software agent design from the theoretical underpinnings of multiagent theory and propose the development of a unifying notation for representing multiagent problems.