基于多Agent协商的虚拟企业伙伴选择方法

伙伴选择是虚拟企业建立过程中的核心问题,分析了虚拟企业的特点、虚拟企业环境下协商问题的特点,提出了一个适合于虚拟企业环境的多Agent协商模型。该模型支持多Agent多议题的多轮谈判,并将Agent类型引入到协商中来,作为指导协商Agent提议的一个重要因素。在不完全信息的条件下,应用贝叶斯学习的方法,更新既有信息,并通过分析对方Agent的历史提议序列,推测其类型,来指导自身的提议策略和战术,使自己的提议更具有针对性,避免了盲目性,从而节约协商时间,提高了协商的效率,使得盟主企业能在尽短的时间里寻找到理想的合作伙伴。     

A toolset for building the virtual enterprise

Much research has been undertaken to define what a virtual enterprise is and how it should work. This paper addresses the specific question, how a virtual enterprise can be designed to have the agility to support short-term business opportunities. A framework is presented for the organizational design and the changing business roles of the business architect who constructs the various phases of the virtual enterprises lifecycle. This infrastructure for creating virtual enterprises is referred to as the value system designer; a set of methods and tools to select partners, re-engineer business- and logistic processes and to set up an information and communication platform for the virtual enterprise. The methods and tools have been developed in two longitudial research projects TELEflow and the Virtuelle Fabrik between 1995 and 1999. Focusing on the experiences gained from numerous cases, a summary on crucial success factors for designing virtual enterprises shall be presented. Thus, this paper gives insights and applicable know-how for companies and managing engineers in their role as virtual enterprise architects, for example leaders of project consortia or joint ventures or as first-tier suppliers co-ordinating supplier (sub-) nets.     

基于多Agent的虚拟企业系统中通信机制

虚拟企业是面向21世纪提高企业竞争力的有力手段。分析了虚拟企业的基本概念、特点以及体系结构；介绍了Agent的定义、特点和有关Multi-Agent的相关内容：提出了基于Multi-Agent的分布式虚拟企业的体系结构，描述了该系统各Agent之间的通信机制。     

Supporting virtual enterprise systems using agent coordination

Open environments like the Internet or corporate intranets enable a large number of interested enterprises to access, filter, process and present information on an as-needed basis. These environments support modern applications, such as virtual enterprises and interorganisational workflow management systems, which involve a number of heterogeneous resources, services and processes. However, any execution of a virtual enterprise system would yield to disjoining and error-prone behaviour without appropriate techniques to coordinate the various business processes. This paper reports on the design and implementation of a flexible agent-based framework for supporting the coordination of virtual enterprises and workflow management systems. The paper also shows how an agent coordination infrastructure, which is explained by social constraints, can impact on the engineering of highly dynamic virtual enterprises and workflow management systems by presenting a simple case study.     

虚拟企业环境下的复杂产品并行开发框架模型研究

为了解决虚拟企业中复杂产品开发的并行调度问题，提出了虚拟企业环境下的复杂产品并行开发框架模型。该模型在采用设计结构矩阵和扩展工作转秽矩阵分析产品并行开发过程中存在的循环迭代基础上，运用遗传算法对开发任务的调度进行优化。仿真结果表明，该框架模型在处理虚拟企业的复杂产品并行开发方面的瓶颈问题有着显著的优势。     

Execution system for distributed business processes in a virtual enterprise

New cooperative approaches for manufacturing and service industries, as represented by the virtual enterprise paradigm, are enabled by the recent advances in communication technologies, computer networks, and logistics. The implantation of this paradigm requires the design and development of a flexible execution environment to support the distributed business processes that materialize the cooperation in a network of enterprises. A configurable architecture for such execution system is proposed focusing the support for multi-level process coordination. A set of examples to illustrate the adopted concepts and developed tools are discussed.     

Distributed shared memory infrastructure for virtual enterprise in building and construction

This paper proposes a new approach to building a virtual enterprise (VE) software infrastructure that offers persistence, concurrent access, coherence and security on a distributed datastore based on the distributed shared-memory paradigm. The platform presented, persistent distributed store (PerDiS), is demonstrated with test applications that show its suitability and adequate performance for the building and construction domain. In particular, the successful adaptation of standard data access interface (SDAI) to PerDiS and a comparison with CORBA are presented as examples of the potential of the distributed shared-memory paradigm for the VE environment.     

Complex service design: A virtual enterprise architecture for logistics service

This paper presents an interdisciplinary systems approach to service modeling, design and deployment. The study is based on a longitudinal case study of the development process of a complex logistic service system based on an advanced logistics model. The case examines the development of a Virtual Enterprise Architecture (VEA) for an automatic high-speed transport and sorting system applied in airports for baggage handling. The study traces the evolution of the system from the early conceptual phases to a successful commercial service deployed at Changi, Singapore Airport. The study is conducted using a retrospective analysis of the case using a design science research approach. The paper evaluates and discusses the issues of creating and designing a new complex logistics service, distinct from the physical product, based on an advanced discrete event-based simulation model. The paper concludes by presenting a generalized and validated conceptual framework for a VEA based on an advanced simulation model. The paper thus contributes to the field of service systems and service management by identifying a novel approach to effective design of a new service.     

Finding influential agent groups in complex multiagent software systems based on citation network analyses

Current complex engineering software systems are often composed of many components and can be built based on a multiagent approach, resulting in what are called complex multiagent software systems. In a complex multiagent software system, various software agents may cite the operation results of others, and the citation relationships among agents form a citation network; therefore, the importance of a software agent in a system can be described by the citations from other software agents. Moreover, the software agents in a system are often divided into various groups, and each group contains the agents undergoing similar tasks or having related functions; thus, it is necessary to find the influential agent group (not only the influential individual agent) that can influence the system outcome utilities more than the others. To solve such a problem, this paper presents a new model for finding influential agent groups based on group centrality analyses in citation networks. In the presented model, a concept of extended group centrality is presented to evaluate the impact of an agent group, which is collectively determined by both direct and indirect citations from other agents outside the group. Moreover, the presented model addresses two typical types of agent groups: one is the adjacent group where agents of a group are adjacent in the citation network, and the other is the scattering group where agents of a group are distributed separately in the citation network. Finally, we present case studies and simulation experiments to prove the effectiveness of the presented model.     

Managing distributed business processes in the virtual enterprise

In this work the supply–chain coordination in the virtual enterprise environment is subject of analysis. The system developed by UFSC-DBPMS—for the management of distributed business process is presented and some basic concepts for its definition and development are detailed. The DBPMS provides means for getting, analyzing, making available and managing the information from and about a virtual enterprise, enabling the enterprises to make their logistics more efficiently by means of an integrated information-based supply-chain management. All the work presented in this paper was developed within the scope of the ESPRIT project PRODNET-II (production planning and management in an extended enterprise).     

Coordinating patient preferences through automated negotiation: A multiagent systems model for diagnostic services scheduling

This paper presents a multiagent systems model for patient diagnostic services scheduling. We assume a decentralized environment in which patients are modeled as self-interested agents who behave strategically to advance their own benefits rather than the system wide performance. The objective is to improve the utilization of diagnostic imaging resources by coordinating patient individual preferences through automated negotiation. The negotiation process consists of two stages, namely patient selection and preference scheduling. The contract-net protocol and simulated annealing based meta-heuristics are used to design negotiation protocols at the two stages respectively. In terms of game theoretic properties, we show that the proposed protocols are individually rational and incentive compatible. The performance of the preference scheduling protocol is evaluated by a computational study. The average percentage gap analysis of various configurations of the protocol shows that the results obtained from the protocol are close to the optimal ones. In addition, we present the algorithmic properties of the preference scheduling protocol through the validation of a set of eight hypotheses.     

Towards an architecture for virtual enterprises

An approach to the design of an architecture for industrial virtual enterprises (VE), with special emphasis on the identification of main functional requirements, is presented. First, a discussion of the various types of virtual enterprises is provided. Some classification scenarios and discussions of the modelling and reengineering tools and methodologies are described. Due to the importance of the information flows and management in the VE, one section is merely devoted to the analysis of the appropriateness of a federated information management approach. This work is based on and represents the ongoing activities in two European Union funded projects; the Esprit PRODNET II and the INCO-DC SCM+ projects.     

Agent-based virtual organization architecture

The purpose of this paper is to present the applicability of THOMAS, an architecture specially designed to model agent-based virtual organizations, in the development of a multiagent system for managing and planning routes for clients in a mall. In order to build virtual organizations, THOMAS offers mechanisms to take into account their structure, behaviour, dynamic, norms and environment. Moreover, one of the primary characteristics of the THOMAS architecture is the use of agents with reasoning and planning capabilities. These agents can perform a dynamic reorganization when they detect changes in the environment. The proposed architecture is composed of a set of related modules that are appropriate for developing systems in highly volatile environments similar to the one presented in this study. This paper presents THOMAS as well as the results obtained after having applied the system to a case study.     

Selection of partners in virtual enterprise paradigm

Agility is the competitive advantage in the global manufacturing environment. It is believed that the agility can be realized by dynamically reconfigurable virtual enterprise. However, the configuration of virtual enterprises is a challenge to us. In selecting the partners for the reconfiguration of virtual enterprise, many factors should be taken into consideration. However, the manufacturing cost and time to market are the most important factors. In this paper, in considering the completion time as a constraint we model the partner selection problem by an integer programming formulation to minimize the manufacturing cost. The formulation is then transformed into a graph-theoretical formulation and a 2-phase algorithm is developed to solve the problem. In the first phase, a polynomial bounded algorithm is proposed to find the earliest completion time, so we obtained a feasible solution. In phase 2, we improve the solution by exchanging the candidate partners in keeping the solution in the feasible region. Although we may not find the optimal solution for the problem by the improvement algorithm, the objective is reduced iteration by iteration. Thus, the algorithm is efficient and can be applicable to practical problems. An illustrative example is presented to show the application of the proposed algorithm.     

Data-driven dynamic bottleneck detection in complex manufacturing systems

Production (throughput) bottlenecks are the critical stations defining and constraining the overall productivity of a system. Effective and timely identification of bottlenecks provide manufacturers essential decision input to allocate limited maintenance and financial resources for throughput improvement. However, identifying throughput bottleneck in industry is not a trivial task. Bottlenecks are usually non-static (shifting) among stations during production, which requires dynamic bottleneck detection methods. An effective methodology requires proper handling of real-time production data and integration of factory physics knowledge. Traditional data-driven bottleneck detection methods only focus on serial production lines, while most production lines are complex. With careful revision and examination, those methods can hardly meet practical industrial needs. Therefore, this paper proposes a systematic approach for bottleneck detection for complex manufacturing systems with non-serial configurations. It extends a well-recognized bottleneck detection algorithm, “the Turning Point Method”, to complex manufacturing systems by evaluating and proposing appropriate heuristic rules. Several common industrial scenarios are evaluated and addressed in this paper, including closed loop structures, parallel line structures, and rework loop structures. The proposed methodology is demonstrated with a one-year pilot study at an automotive powertrain assembly line with complex manufacturing layouts. The result has shown a successful implementation that greatly improved the bottleneck detection capabilities for this manufacturing system and led to an over 30% gain in Overall Equipment Effectiveness (OEE).     

Evaluating software engineering techniques for developing complex systems with multiagent approaches

Context

Multiagent systems (MAS) allow complex systems to be developed in which autonomous and heterogeneous entities interact. Currently, there are a great number of methods and frameworks for developing MAS. The selection of one or another development environment is a crucial part of the development process. Therefore, the evaluation and comparison of MAS software engineering techniques is necessary in order to make the selection of the development environment easier.

Objective

The main goal of this paper is to define an evaluation framework that will help in facilitating, standardizing, and simplifying the evaluation, analysis, and comparison of MAS development environments. Moreover, the final objective of the proposed tool is to provide a repository of the most commonly used MAS software engineering methods and tools.

Method

The proposed framework analyzes methods and tools through a set of criteria that are related to both system engineering dimensions and MAS features. Also, the support for developing organizational and service-oriented MAS is studied. This framework is implemented as an online application to improve its accessibility.

Results

In this paper, we present Masev, which is an evaluation framework for MAS software engineering. It allows MAS methods, techniques and environments to be analyzed and compared. A case study of the analysis of four methodologies is presented.

Conclusion

It is concluded that Masev simplifies the evaluation and comparison task and summarizes the most important issues for developing MAS, organizational MAS, and service-oriented MAS. Therefore, it could help developers to select the most appropriate MAS method and tools for developing a specific system, and it could be used for MAS software engineering developers to detect and deficiencies in their methods and tools. Also, developers of new tools can understand this application as a way to publish their tools and demonstrate what their contributions are to the state of the art.     

Argumentation-based negotiation planning for autonomous agents

When we negotiate, the arguments uttered to persuade the opponent are not the result of an isolated analysis, but of an integral view of the problem that we want to agree about. Before the negotiation starts, we have in mind what arguments we can utter, what opponent we can persuade, which negotiation can finish successfully and which cannot. Thus, we plan the negotiation, and in particular, the argumentation. This fact allows us to take decisions in advance and to start the negotiation more confidently. With this in mind, we claim that this planning can be exploited by an autonomous agent. Agents plan the actions that they should execute to achieve their goals. In these plans, some actions are under the agent's control, while some others are not. The latter must be negotiated with other agents. Negotiation is usually carried out during the plan execution. In our opinion, however, negotiation can be considered during the planning stage, as in real life. In this paper, we present a novel approach to integrate argumentation-based negotiation planning into the general planning process of an autonomous agent. This integration allows the agent to take key decisions in advance. We evaluated this proposal in a multiagent scenario by comparing the performance of agents that plan the argumentation and agents that do not. These evaluations demonstrated that performance improves when the argumentation is planned, specially, when the negotiation alternatives increase.     

Computer-aided prototyping of production flows for a virtual enterprise

This paper presents a logistics framework to cope with the problem of planning and control of production flows processed on a set of work cells distributed among component firms of a virtual enterprise (VE). The constraints theory framework is employed to study constraint-based production flow coordination rules. The article discusses relationships linking structural parameters (e.g. buffer capacity, machine tool efficiency, and automated storage/retrieval systems) of VE components with material flow control guaranteeing efficient completion of work orders, and specified by such parameters as batch delivery periods, work-in-process (WIP) and make-span. The results are summarized in the form of a performance evaluation scheme. Examples using a software package that implements the proposed flow coordination methodology are provided.     

A virtual actuator and sensor approach for fault tolerant control of LPV systems

In this paper, a fault tolerant control (FTC) strategy using virtual actuators and sensors for linear parameter varying (LPV) systems is proposed. The main idea of this FTC method, initially developed for LTI systems, is to reconfigure the control loop such that the nominal controller could still be used without need of retuning it. The plant with the faulty actuator/sensor is modified adding the virtual actuator/sensor block that masks the actuator/sensor fault. The suggested technique is an active FTC strategy that reconfigures the virtual actuator/sensor on-line taking into account faults and operating point changes. The stability of the reconfigured control loop is guaranteed if the faulty plant is stabilizable/detectable. The LPV virtual actuator/sensor is designed using polytopic LPV techniques and linear matrix inequalities (LMIs). A two-tank system simulator is used to assess the performance of the proposed method. In particular, it is shown that the application of the proposed technique results in an improvement, in terms of performance, with respect to the LTI counterpart.