Cooperation coordination in virtual enterprises

Coordination of activities is a determinant element in virtual enterprises. Proper coordination policies supported by flexible coordination mechanisms are necessary to ensure the cooperation among partner enterprises. This paper presents the PRODNET approach to support coordination in virtual enterprises. The adopted model considers on flexibility and configurability as the key aspects to cope with the large diversity of expectable scenarios and operating policies in the virtual enterprise environment. A workflow based approach for coordination is described and especial emphasis is put on a multi-level coordination view. The developed software modules that support the coordination mechanisms are presented, and finally some directions for further research are given.     

一种基于多代理技术实现的虚拟企业中的敏捷调度

提出了一种用多代理技术和基于协商的策略解决虚拟企业调度冲突的方法。首先介绍了虚拟企业中敏捷调度的特性及调度冲突的产生,分类及解决方法,并描述了调度、计划、协商、监督执行之间的互操作,通过代理的智能,自治等特性可以较好地实现调度的敏捷性,最后给出了在一个面向虚拟企业的信息集成系统ViaSopc中基于多代理技术实现的基于协商的敏捷调度模型。     

Multi-point impedance control for redundant manipulators

This paper proposes an impedance control method called the multi-point impedance control (MPIC) for redundant manipulators. The method can not only control end-effector impedance, but also regulate impedances of several points on the links of the manipulator, which are called virtual end-point impedances, utilizing arm redundancy. Two approaches for realizing the MPIC are presented. In the first approach, controlling the end-effector impedance and the virtual end-point impedances are considered as the tasks with the same level, and the joint control law developed in this approach can realize the closest impedances of the multiple points, including the end-effector and the virtual end-points to the desired ones in the least squared sense. On the other hand, in the second approach, controlling the end-effector impedance is considered the most important task, and regulating the impedances of the virtual end-points is considered as a sub-task. Under the second approach, the desired end-effector impedance can be always realized since the joint control torque for the regulation of the virtual end-point impedances is designed in such a way that it has no effect on the end-effector motion of the manipulator. Simulation experiments are performed to confirm the validity and to show the advantages of the proposed method.     

A framework for virtual enterprise operation management

This paper presents researches on operation management for virtual enterprises (VEs). A virtual enterprise is a temporary alliance of member enterprises (MEs) formed to exploit fast-changing opportunities. During the operation of a virtual enterprise, its constituent member enterprises, which are geographically distributed and organizationally independent, collaborate with each other to execute the whole business process (BP) of the virtual enterprise. With the aim of addressing business integration for virtual enterprises, this paper develops a framework for virtual enterprise operation management. From the viewpoint of business processes, carried out is integral research on business process modeling, analyzing, and managing for virtual enterprises. Both the distributed business process model and the model of the virtual enterprise itself are established. The former provides the functional basis of the virtual enterprise operation, while the latter provides its structural basis. Further, the two models are integrated through the loading from the distributed business process model to the virtual enterprise model. Through such model separation and integration, business process management for virtual enterprises is enacted and business integration for virtual enterprises is achieved.     

基于工作流的虚拟企业信息管理模型

现代企业生产环境随着生产的全球化已经跨越 了国界,进行全球范围内的资源优化配置是有效利用全球资源的理想方案, 虚拟企业正是在 此需求下产生的．由于虚拟企业的分布式特点,其信息管理不同于传统的本地的管理方式． 本文给出一个基于工作流的虚拟企业信息管理模型,此模型支持的异构环境是地理上分散的 ,涉及到不同的应用包,多平台、多协议和多种用户界面,为虚拟企业生产信息管理提出了 一种方案．     

Cost optimization in persistent virtual world design

Virtual world has the potential to become a future global electronic market, integrating many isolated markets in many areas. To achieve this goal, future virtual world is required to be persistent, which means that a virtual world together with its accumulated content shall exist forever regardless of the dynamic changes of its virtual world users and virtual world owners. This paper addresses the content-level persistence issue by proposing a persistence framework which consists of three elements: existence, availability, and sufficiency. Following the framework, a decentralized redundancy model is then proposed, which is immune from the possible collapse of virtual world. The key problem in the model is the selection of a redundancy level, which is based on cost optimization. Furthermore, the replica failure timeout mechanism is introduced to improve the model. The simulation results show that the redundancy model helps improve content availability and minimizes cost.     

支持中小企业动态联盟的企业资源计划体系

在讨论ERP系统与应用企业的匹配性、中小企业动态联盟的特点及其ERP系统特征的基础上，提出一个基于盟主企业和盟员企业两大层面的ERP结构体系，并阐述了中小企业动态联盟在所设计的ERP环境下协同工作的业务流程．     

A framework for organization network engineering and integration

Nowadays, virtual enterprises, extended enterprises, wide supply chains and enterprise networks are organizational structures recognized by the scientific and professional communities. The challenges in engineering these systems consist in providing solutions that take into account both the social and the technical aspects simultaneously. This paper presents an engineering framework for organization networks. Beside the introduction of a set of necessary components to develop such a framework, the paper offers new modelling concepts, a modelling approach and a reference architecture for organization networks.     

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.     

Redundancy Control of a Humanoid Head for Foveation and Three-Dimensional Object Tracking: A Virtual Mechanism Approach

This paper presents a novel approach for object tracking with a humanoid robot head. The proposed approach is based on the concept of a virtual mechanism, where the real head is enhanced with a virtual link that connects the eye with a point in three-dimensional space. We tested our implementation on a humanoid head with 7 d.o.f. and two rigidly connected cameras in each eye (wide-angle and telescopic). The experimental results show that the proposed control algorithm can be used to maintain the view of an observed object in the foveal (telescopic) image using information from the peripheral view. Unlike other methods proposed in the literature, our approach indicates how to exploit the redundancy of the robot head. The proposed technique is systematic and can be easily implemented on different types of active humanoid heads. The results show good tracking performance regardless of the distance between the object and the head. Moreover, the uncertainties in the kinematic model of the head do not affect the performance of the system.     

Industrial applications of agent technologies

This paper is aimed at summarizing the current state-of-the-art in the development of agent-based solutions in three areas connected with industrial production, namely in holonic control, production management and virtual enterprises. This paper shows how the results in these three sub-areas are converging and discusses how the agent-oriented technologies could provide a good background for developing a unifying approach. Two industrial applications of agent-based systems are described in some detail. The paper also presents both the positive and negative aspects of applying agent-based technologies in industry.     

用虚拟连杆构造冗余残差对多关节机械臂进行故障诊断

提出了一种多关节机械臂的故障诊断方法.基于机械臂各个关节间的转动传递关系,对多个关节构造虚拟连杆的残差,利用虚拟连杆与机械臂工作空间残差间构成的冗余关系进行故障诊断.将残差阈值的设计与机械臂末端位置的渐变相联系,改进了现有方法中判别关节故障没有利用关节间位置关系的不足.     

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.     

基于VRRP+MSTP协议的可靠性网络设计

针对现代企业对网络的可靠性需求,根据VRRP(Virtual Router Redundancy Protocol)和MSTP (Multiple Spaning Tree Protocol)协议理论,设计了一种方案使企业在访问网络中心数据时能实现路由冗余和负载均衡,在跨交换机同一子网内互访时也能够实现路由冗余和负载均衡,从而保证企业内关键业务的不间断运行,实现了网络的可靠性设计.     

Agent-based optimisation of logistics and production planning

Manufacturing and logistics service provision enterprises are currently moving towards open virtual enterprise collaboration networks to meet the needs of the Global Economy. In such networks, manufacturing and logistics planning and scheduling is challenging due to the difficulties in integrating information from different partners and in exploring a large and dynamically changing number of planning and scheduling alternatives. Agent-based technology is considered suitable to support planning and scheduling in such enterprises because agents can dynamically adapt their behaviour to changing requirements and they can reduce the number of planning and scheduling alternatives via negotiation.This paper presents an agent-based approach for supporting logistics and production planning, taking into account not only production schedules but also availability and cost of logistic service providers. This is achieved through efficient negotiation mechanisms based on an extended contracting protocol. The agent infrastructure is being developed within the context of Agentcities, a successful EU-funded initiative to build a world-wide distributed and open platform which provides agent-based services.The proposed approach is illustrated in a case study concerning optimisation of production planning of a virtual manufacturing enterprise in relation to sub-contracted logistic services used to transport materials between the enterprise units.     

Pattern-based e-service modelling for virtual service enterprises

Business services are customisable, interactive processes that providers have the potential to carry out together with clients that benefit from the effects. It is understood that business service transactions are best organised by means of virtual networks, where information technology allows for configuring multiple providers and processes on a per-request basis. Existing conceptual models for virtual service enterprises (VSEs) propose business service virtualisation for flexible and agile regulation and control of coordination between multiple providers and clients. In this paper, we present an approach for realising business service virtualisation based on software service technology. In particular, we propose a service-oriented software architecture for representing virtual business service processes as e-services. E-service models specify flexible business service interactions between multiple providers and clients of virtual service enterprises and allow for regulation and enforcement of their coordination. We demonstrate the utilisation of our e-service SOA in the context of an e-science scenario, where we show how to design e-service models for the use case of virtual polymorph prediction laboratories.     

基于Internet/Intranet的供应链企业VPN解决方案研究

研究基于Internet/Intranet的供应链企业VPN解决方案 ,分析了集成化供应链信息安全的需求 ,并阐述了VPN在供应链管理中所起的作用 ,提出了一个基于Internet/Intranet的集成化供应链企业VPN解决方案 ;详细介绍了供应链企业VPN系统的实施步骤     

Dynamic Analysis and Distributed Control of the Tetrobot Modular Reconfigurable Robotic System

Reconfigurable robotic systems can be adapted to different tasks or environments by reorganizing their mechanical configurations. Such systems have many redundant degrees of freedom in order to meet the combined demands of strength, rigidity, workspace kinematics, reconfigurability, and fault tolerance. In order to implement these new generations of robotic system, new approaches must be considered for design, analysis, and control. This paper presents an efficient distributed computational scheme which computes the kinematics, dynamics, redundancy resolution, and control inputs for real-time application to the control of the Tetrobot modular reconfigurable robots. The entire system is decomposed into subsystems based on a modular approach and Newton's equations of motion are derived and implemented using a recursive propagation algorithm. Two different dynamic resolution of redundancy schemes, the centralized Jacobian method and the distributed virtual force method, are proposed to optimize the actuating forces. Finally, distributed dynamic control algorithms provide an efficient modular implementation of the control architecture for a large family of configurations.     

虚拟企业信息基础结构的构建

敏捷制造依赖虚拟企业这种组织形式来实现。该文分析了在敏捷制造中包含的信息来源、信息类型及信息特点等,从虚拟企业运作的信息需求出发,明确构建支持虚拟企业运作的信息基础结构需要解决的问题,在分析总结现有信息技术的基础上,提出其构建方案。