Specification -- The Role of Castes in Formal Specification of MAS -- A Truly Concurrent Model for Interacting Agents -- Reliable Agent Computation: An Algebraic Approach -- An Argument-Based Agent System with KQML as an Agent Communication Language -- Modeling -- On Fairness in an Alternating-Offers Bargaining Model with Evolutionary Agents -- Sealed Bid Multi-object Auctions with Necessary Bundles and its Application to Spectrum Auctions -- Strategic Multi-Personal-Agent Interaction -- Market Performance of Adaptive Trading Agents in Synchronous Double Auctions -- Negotiation-Credit Driven Coalition Formation in E-Markets -- Applications -- An Adaptive Agent Society for Environmental Scanning through the Internet -- Gaz-Guide: Agent-Mediated Information Retrieval for Official Gazettes -- Technological Innovation of High-tech Industry and patent policy -Agent based Simulation with Double Loop Learning- -- Collaborative Filtering for a Distributed Smart IC Card System -- Incorporating content-based collaborative filtering in a community support system -- A Personal Agent for Bookmark Classification -- Scalable Workflow System Model Based on Mobile Agents.

The increasing importance of intelligent agents and their impact on industry/business worldwide is well documented through academic research papers and industrial reports. There is a strong affinity between the Web a worldwide distributed computing environment and the capability of intelligent agents to act on and through software. The ultimate goal of intelligent agents is to accelerate the evolution of the Web from a passive, static medium to a tuned, highly valued environment. This volume contains selected papers from PRIMA 2001, the fourth Pacific Rim International Workshop on Multi-Agents, held in Taipei, Taiwan, July 28-29, 2001. In this volume, the papers cover specification, modeling, and applications of intelligent agents. PRIMA is a series of workshops on autonomous agents and multi-agent systems, integrating the activities in Asia and the Pacific Rim countries. PRIMA 2001 built on the great success of its predecessors, PRIMA98 i n Singapore, PRIMA99 i n Kyoto, Japan, and PRIMA 2000 in Melbourne, Australia. The aim of PRIMA 2001 was to bring together researchers from Asia and the Pacific Rim and developers from academia and industry to report on the latest technical advances or domain applications and to discuss and explore scientific and practical problems as raised by the participants.