Formulation and analysis of dynamic supply chain of backfill in construction waste management using agent-based modeling

Backfill is the excavated material from earthworks, which constitutes over 50% of the construction wastes in Hong Kong. This paper considers a supply chain that consists of construction sites, landfills and commercial sources in which operators seek cooperation to maximize backfill reuse and improve waste recovery efficiency. Unlike the ordinary material supply chain in manufacturing industries, the supply chain for backfill involves many dynamic processes, which increases the complexity of analyzing and solving the logistic issue. Therefore, this study attempts to identify an appropriate methodology to analyze the dynamic supply chain, for facilitating the backfill reuse. A centralized optimization model and a distributed agent-based model are proposed and implemented in comparing their performances. The centralized optimization model can obtain a global optimum but requires sharing of complete information from all supply chain entities, resulting in barriers for implementation. In addition, whenever the backfill supply chain changes, the centralized optimization model needs to reconfigure the network structure and recompute the optimum. The distributed agent-based model focuses on task distribution and cooperation between business entities in the backfill supply chain. In the agent-based model, decision making and communication between construction sites, landfills, and commercial sources are emulated by a number of autonomous agents. They perform together through a negotiation algorithm for optimizing the supply chain configuration that reduces the backfill shipment cost. A comparative study indicates that the agent-based model is more capable of studying the dynamic backfill supply chain due to its decentralization of optimization and fast reaction to unexpected disturbances.     

Agents and the Internet: infrastructure for mass customization

Major market trends are driving the manufacturing complex from mass production, where the manufacturer tells the customer what to buy, to mass customization, where the customer tells the manufacturing complex what to make. The Internet supports this transformation with global communication between customers and manufacturers. However, the physical realities of manufacturing impose requirements for more than just communication. In some sense, manufacturing enterprises must actually exist over the Internet as an efficiently managed distributed enterprise. Software agents offer a means to achieve this link and thus a reliable global infrastructure for mass customization. The AARIA project provides a demonstration of how the manufacturing complex can move toward mass customization by using the Internet as a natural platform for managing distributed operations and by using autonomous agents as the tools for efficiently reconfiguring available productive resources. We begin by looking at the unique requirements manufacturing imposes on the infrastructure for virtual enterprises and describing the AARIA project components for meeting them. We then describe our scheduling technologies for efficient distributed resource management     

鲁棒性项目调度中缓冲设置方法

研究应对不确定因素的鲁棒性项目调度, 针对其所用时间缓冲区技术中的两种重要方法——集中缓冲和STC (starting time criticality) 分散缓冲, 采用仿真模拟实验, 以项目管理库中的帕特森例1 为对象, 进行详细的比较研究. 研究结果表明, 分散缓冲法具有更好的解鲁棒性; 当活动时间的不确定性程度较大时, 集中缓冲法的质量鲁棒性较好; 当项目工期较紧时, 分散缓冲法具有更好的鲁棒性. 这些研究结论为管理者在特定的项目环境下选择合适的缓冲方法提供了决策依据.     

考虑产品替代的供应链协调问题研究

替代品大大增加了企业间的竞争,使企业难以达到所期望的盈利水平。对供应链进行合理有效的管理可最大限度地促进企业适应当今多变的市场环境。人们对于产品的需求不仅仅取决于产品本身的价格,也取决于互补产品的价格。对此,构建一个以产品替代的供应链协调问题为研究目标,以两种供应链管理模式(集中供应链(CSC)和分散供应链(DSC))为依托,通过建立混合整数规划模型并对相关参数进行验证,得出集中供应链模式更能灵活应对当今市场。     

Agent-Based Supply Chain Integration

Supply chain management represents a critical competency in today's fast-paced, global business environment. However, in the current transition from EDI to Web-based supply chain technologies, much of the capability for process integration is being lost. And the integration of buyer and seller supply chain processes is critical for speed and responsiveness in today's hypercompetitive product and service markets. Intelligent agent technology offers the potential to overcome many limitations of current supply chain technologies. This paper presents intelligent supply chain agents that represent and autonomously conduct business on behalf of product users, buyers and vendors. We classify and present numerous extant agent applications and extend a technological framework to compare and contrast intelligent agents with other classes of information technology. We then describe an agent-based supply chain process design, along with its developmental techniques, and the structure and behavior of an agent federation used for integration in a major enterprise. We present results of this exploratory research in terms of technical feasibility and process performance in the enterprise context. This work is novel in that it integrates process-level knowledge from operational enterprises with distributed agent technologies. And it makes a contribution by demonstrating how agent-based supply chain integration can be effected along a large-scale, operational, inter-organizational process.     

网络流量技术应用与分析

随着因特网的高速发展，IP网络承载的数据流量越来越大，需要了解IP网络的整体性能及流量状况来适应业务的发展。本文阐述当前主要的流量技术NETFLOW与RMON2的原理、结构和关键技术，提出了基于NETFLOW技术的应用分析，并对RMON2与NETFLOW的应用进行了比较分析。     

Distributed and centralised material handling scheduling: Comparison and results of a simulation study

Part of a larger research that employs decentralized holonic modelling techniques in manufacturing planning and control, this work proposes a holonic-based material handling system and contrasts the centralized and distributed scheduling approaches for the allocation of material handling operations to the available system resources. To justify the use of the decentralized holonic approach and assess its performance compared to conventional scheduling systems, a series of evaluation tests and a simulation study are carried out. As illustrated by the results obtained from the simulation study, the decentralized holonic approach is capable of delivering competitive feasible solutions in, practically, real-time.     

A case study of an inter-enterprise workflow-supported supply chain management system

Doing business over the Internet is cheap and convenient. This enlarges the view of enterprises and gives them an opportunity to select their partners. To support business-to-business operations, an information system (IS) with an embedded workflow management component is needed. The inherent characteristics of such a system makes it suitable to implement cross-organization management. Nowadays, however, these system additions are not common. When developing a supply chain management (SCM) system for a large motorcycle corporation in China, we had to construct an inter-enterprise architecture using the internet. The main part of this is a workflow-supported inner supply chain system and an integrated interface. In it, the business processes are defined and executed by the supply chain management system. The independent inner systems are connected by the integrated interface into a large, global, supply chain manage system to management business processes across the independent enterprises. This paper presents the system design and implementation and discusses our experiences and lessons learned.     

Making IT global – what facility management brings to the table?

ABSTRACT

Globalization retains an imposing future for the managers of numerous companies, while the global information systems (IS) play a significant role in the connection, collection, access and analysis of information produced in interrelated operations from numerous national markets. The popularity of such systems in textile, manufacturing, finance and supply chain grows, as well as the development of IT support for global services remains a challenge. Through a Participatory Action Research project in a global service provider specialized in Facility Management, we investigated the necessity of introducing a systematic integrative approach by a national company for the Global System Development and approaching the issues emerging in a multinational context. As a result, an expansion model for a globalizing company was synthesized and the issues regarding its application discussed. The cultural differences involved in Facility Management market operation regarding both developing and developed European countries were identified and functionality, non-functional requirements and architecture of a global IS were elaborated. Finally, IS development strategy/development process management is outlined for corporations to achieve and maintain global competitiveness.     

带运输时间的无等待供应链在线调度问题研究

研究了供应链在线调度问题.该问题具有工件无等待、工序之间存在运输时间、加工时间介于一个区间等特点,制造商随时可能接到顾客订单,订单到达前,所有信息如订单数量、到达时间及加工时间等均未知.研究了在不改变已有工件调度的情况下,使用资源的可用时间区间最早完成临时订单的算法.计算机仿真表明,使用该算法求解大规模临时订单问题是十分有效的.     

基于全局目录的分布式数据库加锁管理算法

针对简单的分布式封锁方法和完全分布式加锁算法在加锁时所需通信开销大、封锁时间长、锁管理复杂的缺点,结合集中式数据库加锁管理算法的优点,指出了在分布式数据库中保持事务可串行化方面存在的难点,利用全局目录和事务调度器,提出了基于全局目录的分布式数据库加锁管理算法。该算法使用两阶段封锁协议和多粒度封锁协议,在全局目录服务器中使用全局锁管理器管理和维护全局目录中的锁结点信息并对分布式封锁请求进行集中控制和灵活管理,能有效地保证事务的可串行化调度,降低封锁时的通信开销。     

基于分布式结构的供应链信息控制机制

对分布式供应链中的错劣信息的传播机制进行了研究，通过建立微分方程刻划错劣信息的传播模型。供应链管理者为控制错劣信息的传播应采取持久且高强度的纠偏或绩效优化措施。     

Dynamic supply chain scheduling

Based on a combination of fundamental results of modern optimal program control theory and operations research, an original approach to supply chain scheduling is developed in order to answer the challenges of dynamics, uncertainty, and adaptivity. Both supply chain schedule generation and execution control are represented as an optimal program control problem in combination with mathematical programming and interpreted as a dynamic process of operations control within an adaptive framework. Hence, the problems and models of planning, scheduling, and adaptation can be consistently integrated on a unified mathematical axiomatic of modern control theory. In addition, operations control and flow control models are integrated and applicable for both discrete and continuous processes. The application of optimal control for supply chain scheduling becomes possible by formulating the scheduling model as a linear non-stationary finite-dimensional controlled differential system with the convex area of admissible control and a reconfigurable structure. For this model class, theorems of optimal control existence can be used regarding supply chain scheduling. The essential structural property of this model are the linear right parts of differential equations. This allows applying methods of discrete optimization for optimal control calculation. The calculation procedure is based on applying Pontryagin’s maximum principle and the resulting essential reduction of problem dimensionality that is under solution at each instant of time. The gained insights contribute to supply chain scheduling theory, providing advanced insights into dynamics of the whole supply chains (and not any dyadic relations in them) and transition from a partial “one-way” schedule optimization to the feedback loop-based dynamic and adaptive supply chain planning and scheduling.     

基于网格的供应链信息系统的建模与分析

当今供应链的竞争已成为企业竞争的焦点,构建一个分布式、集成化的供应链管理信息系统已成为关键。结合供应链管理信息系统的特点,并基于Globus Toolkit和开放网格服务架构,该文构建了基于开放网格基础设施的供应链管理信息系统的模型。并通过一个实例利用时间Petri网进行建模分析,验证了该模型在提高供应链效率方面的作用。     

Global Supply Chain Design

I review principles and methods of global supply chain design, especially from two viewpoints, in this paper. The first perspective is focused on the practitioner who is interested in an overview of the key concepts and applications of supply chain design within a global context. The second theme of this paper is to assess opportunities for research to extend supply chain design in useful directions, particularly into closely related areas such as supply chain operations and information systems.     

钢铁供应链生产计划与调度研究综述

在供应链管理及竞争的背景下,提出钢铁供应链的概念。该钢铁供应链由矿山、钢铁企业、分销商和用户组成,其管理核心是生产计划与调度。分析了钢铁供应链的生产计划与调度研究内容和特点,综述了研究现状,指出了存在的不足。最后,提出了钢铁供应链生产计划与调度工作进一步研究的问题。     

基于Web服务的全球供应链研究与实现

引入了基于Web服务的全球供应链的思想,介绍了基于Web服务的全球供应链的应用集成框架,阐明了Web服务是如何形成高层次接口,并通过这个接口,企业可以用一种松散的方式更加容易地找到彼此,并进行商务集成和运营,从而实现真正意义上的全球合作伙伴的正确选择和敏捷EA1。最后以在线应用服务系统CFCC(CAD File Conversion Center,CAD文件转换中心)的建立作为工程应用实例。     

Item dwell time in project inventories: A field experiment

This paper describes the use of item dwell-time measurement in the context of capital investment projects. It contributes to the research on product-centric control and intelligent products by empirically demonstrating the value of item dwell-time alerts in the context of project delivery. The paper shows how item dwell-time measurement can be implemented in the field, and compares item dwell-time alerts to conventional measures of inventory turnover and inventory value in four telecommunications infrastructure projects. We find that when individual items cannot be used interchangeably at project sites, conventional inventory measures do not provide sufficiently timely and accurate information about emerging problems in project inventories. These findings are especially important in situations in which supply chain managers can find alternative uses for materials at other sites or in other projects. Timely reallocation of materials prevents the accumulation of slow-moving items that weigh on project performance by increasing obsolescence and inventory holding costs.     

一种基于交流成本的全球软件任务调度方法*

在全球软件开发中,由于时区、地理位置、文化和语言等各种因素,交流和协作变得非常困难,如果在进行任务调度的时候不考虑交流对整个项目所造成的影响,则有可能使整个项目开发的总成本增加,从而给项目带来很大的风险。通过采用基于交流成本的任务调度方法,在项目初期就考虑交流风险,并对任务进行调度,从而能有效减少该风险对项目可能造成的损失。通过一个示例项目将该方法与传统的基于阶段的方法进行对比,说明了交流成本对整个项目成本的确有很重要的影响,并且使用基于交流成本的任务调度方法能有效降低项目开发的总成本。     

A web-based approach for exceptions management in the supply chain

This research aims at developing collaborative planning and scheduling in complex and dynamic supply chains by providing a software architecture and a methodology to define cooperation in a distributed environment. The study contributes to gain the competitive advantage at the extended enterprise, since it analyzes the implications of changes occurred at a certain point of the supply chain for other nodes. This way, the different production schedules of the supply chain are coordinated in order to find a best global solution, thus leading to more realistic plans, better due date fulfilment and less inventory levels in the supply chain as a whole. The general framework of the project using a decentralized approach can be defined by means of three subsystems of communication based on agents: (i) a communication subsystem inside the plants, which will manage the unforeseen events that may lead to a rescheduling of part or the entire production plan, (ii) an inter-plants communication subsystem, which will manage the events produced in a plant that may affect other plants and (iii) a supply chain communication subsystem, which will manage events occurred in a plant that can affect suppliers and/or customers. Next steps will include full development and systematic tests of the prototype that will check the suitability of the architecture and algorithms selected. This research is being funded by Grant PI2008-08 from the Basque Government in Spain.