An Agent-based Framework for Supply Chain

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    An agent-based framework for supply chain

    coordination in construction

    Xiaolong Xuea, Xiaodong Lia, Qiping Shenb,*, Yaowu Wanga

    aSchool of Management, Harbin Institute of Technology, PR ChinabDepartment of Building and Real Estate, The Hong Kong Polytechnic University, Hong Kong

    Received 1 February 2004; received in revised form 1 July 2004; accepted 1 August 2004

    Abstract

    Supply chain coordination has become a critical success factor for supply chain management (SCM) and effectively

    improving the performance of organizations in various industries. Coordination refers to the integration of different parts of an

    organization or different organizations in supply chain to accomplish a collective set of tasks and to achieve mutual benefits.

    This paper defines the concepts of construction supply chain (CSC) and construction supply chain management, especially

    regards construction supply chain management as the coordination of interorganizations decision making in construction supply

    chain and the integration of key construction business processes and key members involved in construction supply chain. Much

    research and practice indicate that there still are many problems in construction, most of which are supply chain problems. The

    research analyzes the problems in construction supply chain. In order to resolve these problems and improving the performance

    of construction, an agent-based framework for construction supply chain coordination is designed based on the agent

    technology and multiattribute negotiation and multiattribute utility theory (MAUT). The framework, which integrates the

    construction organizations in construction supply chain and multiattribute negotiation model into a multiagent system (MAS),

    provides a solution for supply chain coordination in construction through multiattribute negotiation mechanism on the Internet.

    Finally, the prototype of the framework is developed and tentatively run based on an imaginary construction project. The trial

    run reveals the feasibility to implement the agent-based framework for coordination in construction.

    D 2004 Elsevier B.V. All rights reserved.

    Keywords: Construction; Coordination and management; Intelligent agent; Multiattribute negotiation; Multiagent systems; Supply chain

    1. Introduction

    In recent years, the application of supply chain

    management (SCM) philosophy to the construction

    industry has been widely investigated as an effective

    and efficient management measure and strategy to

    improving the performance of construction, which has

    suffered from high fragmentation, large waste, poor

    productivity, cost and time overruns, and conflicts and

    disputes for a long time [13], and to address

    adversarial interorganizational relationship of organ-

    0926-5805/$ - see front matterD 2004 Elsevier B.V. All rights reserved.

    doi:10.1016/j.autcon.2004.08.010

    * Corresponding author.

    E-mail address: [email protected] (Q. Shen).

    Automation in Construction 14 (2005) 413430

    www.elsevier.com/locate/autcon

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    ization by increasing number of construction organ-

    izations and researchers [1,412]. SCM can be

    considered as the coordination of distributed decision

    making of organizations or participants on materialflow, information flow, human flow, and cash flow in

    supply chain from systems perspective.

    According to Lau et al. (2004) [48], SCM is

    defined as bcoordination of independent enterprises in

    order to improve the performance of the whole supply

    chain by considering their individual needsQ. This

    definition describes the main function and principle of

    SCM, i.e., coordination. Swaminathan and Tayur [13]

    classify SCM issues into two broad categories:

    configuration (design-oriented) issue that relates to

    the basic infrastructure on which the supply chainexecutes, and coordination (execution-oriented) issues

    that relate to the actual execution of supply chain.

    Schneeweiss and Zimmer [14] also regard SCM as a

    management activity that has to do with the coordi-

    nation of logistic process being locally controlled by

    various independent organizations (decision-making

    units) in the environment of internationalization and

    globalization of markets together with an increased

    focus on organizations core competence. Up to now,

    supply chain coordination has become a very popular

    research topic among the research community in SCM

    and a vital management issue of organizations in the

    collaborativecompetitive business environment.

    Coordination is bmanaging the dependencies

    between activitiesQ [15]. It is defined as a mutually

    beneficial and well-defined relationship entered into

    by two or more organizations to achieve common

    goals. It also refers to the integration of different parts

    of an organization or different organizations in supply

    chain to accomplish a collective set of tasks and to

    achieve mutual benefits. It involves more formal

    relationships, objectives and actions which are

    mutual, compatible and common, not necessary acentralized authority [16].

    Multiagent systems (MAS) technology offers new

    means and tools for supply chain coordination [17,18].

    According to Wooldridge and Jennings (1995) [49], an

    agent is a self-contained program capable of control-

    ling its own decision making and acting based on its

    perception of its environment, in order to one or more

    goals. An agent must possess any two of the following

    three behavioral attributes: autonomy, cooperation, and

    learning [19]. MAS comprises a number of intelligent

    agents, which represents the real world parties and co-

    operate to reach the desired objectives. In MAS, each

    agent attempts to maximize its own utility while

    cooperating with other agents to achieve their goals[20]. The main advantage of MAS is its responsibilities

    for acting various components of the engineering

    process or participants of the business process which

    is delegated to a number of agents. MAS is suitable for

    domains that involve interactions between different

    organizations with different objectives and proprietary

    information [21]. Based on these discussions, we can

    clearly see that SCM system is a typical MAS, where

    the participants are delegated to different agents.

    Furthermore, agent-based supply chain coordination

    has been proved to be an effective mechanism toimprove the performance of SCM [2224].

    The core principles of SCM and agent technology

    provide new perspectives for construction supply chain

    (CSC) management. However, little research has been

    conducted to investigate the application of intelligent

    agent to coordination problems in CSC. The Centre for

    Integrated Facility Engineering of Stanford University

    established a distribution cooperative CAD environ-

    ment entitled AgentCAD, which presented a frame-

    work for collaborative distributed facility engineering

    [25]. Anumba et al. [26] presented the key features of

    an agent-based system for collaborative design of

    portal frame structures and made a significant contri-

    bution by allowing for peer to peer negotiation between

    design agents. Pena-Mora and Wang [27] proposed a

    collaborative negotiation methodology and a computer

    agent named CONVINCER, which incorporates that

    methodology to facilitate or mediate the negotiation of

    conflicts in large-scale civil engineering projects. Min

    and Bjornsson [28] presented a conceptual model of

    agent-based supply chain automation, in which a

    project agent gathers actual construction progress

    information and sends to subcontractor agents andsupplier agents, respectively, over the Internet. They

    evaluated an agent-based SCM model compared with

    traditional SCM practice through simulation. Ren et al.

    [29] developed multiagent system for construction

    claims negotiation (MASCOT) to resolve inefficiency

    problems. Kim and Paulson [30] presented an agent-

    based compensatory negotiation methodology to facil-

    itate the distributed coordination of project schedule

    changes wherein a project can be rescheduled dynam-

    ically through negotiation by all of the concerned

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    subcontractors. The methodology consists of a com-

    pensatory negotiation strategy based on utility of

    timing, multilinked negotiation protocols, and mes-

    sage-handling mechanisms.Whereas these researchers have addressed a

    number of key issues in the field of CSC, very few

    researchers have considered CSC management as the

    coordination of interorganizations decision making in

    CSC and apply the agent technology into the whole

    CSC management from a systemic perspective. Most

    research projects tend to look into agent-based

    internal coordination of an organization, which

    focuses on one of the stages in CSC, such as design

    coordination, project schedule changes coordination,

    and construction claims and conflicts resolving. Theseapproaches may lead to the optimization of a number

    of subsystems; however, the sum of the optimized

    subsystems may present a problem to the optimization

    of the system as a whole.

    This paper presents an agent-based framework for

    supply chain coordination in construction (ABS3C)

    based on multiattribute negotiation and utility theory,

    which integrates design and construction, and organ-

    izations (or participants), including owner, designer,

    general contractor (GC), subcontractors, and suppliers

    in CSC. This integrated coordination framework

    extends the internal supply chain of general contractor

    to external supply chain of designer, subcontractors,

    and suppliers. In the decision-making process of

    participants in CSC, the factors: cost, time, quality,

    safety, and environment normally are considered as

    the main decision-making variables. Here, we regard

    the five factors as five attributes of decision making in

    the construction process. An agent-based multiattri-

    bute negotiation mechanism is designed for support-

    ing the realization of the framework. The research

    methodology is described. The concepts and problems

    of CSC are defined and discussed. A prototype systemof the agent-based framework for supply chain

    coordination in construction has been evaluated

    through the use of a hypothetical construction project

    and a toolkit called ZEUS.

    2. Theoretical foundation

    According to Pena-Mora and Wang [27], negotia-

    tion theory is the study of exchanges between

    participants to reconcile their differences and produce

    a settlement. Negotiation is defined as one kind of

    decision-making process where two or more partic-

    ipants jointly search for a space of solution with thegoal of achieving consensus [31]. From this defini-

    tion, it can be found that negotiation is an effective

    mechanism for supply chain coordination in con-

    struction. A successful negotiation needs a number of

    elements in the negotiation process. For example, the

    participants have a commitment to settle the matter at

    hand; good communication skills are required; there is

    an agreement between participants on what is actually

    the matter under negotiation. There are three out-

    comes of negotiation: win/win, win/lose, and lose/

    lose. The win/win outcome meets the needs of bothparticipants [32]. One of the objectives of our research

    is to achieve the win/win outcome.

    Since a number of factors, such as cost, time,

    quality, safety, and environment, must be considered

    in the decision-making process of CSC management,

    our research adopts the multiattribute negotiation

    technology to coordinate the CSC. These factors are

    regarded as the attributes involved in CSC decision

    making. The multiattribute negotiation technology is

    developed based on the multiattribute utility theory

    (MAUT), which is an analytical tool for making

    decisions involving multiple interdependent objec-

    tives based on uncertainty and utility analyses [33]

    and an evaluation scheme for estimating various

    products and performance [34,35]. This research

    adopts MAUT to evaluate CSC decision-making

    problems. The procedure of MAUT application to

    supply chain coordination in construction is shown in

    Fig. 1 (adapted from Ref. [36]), where a decision is

    one of a set of possible solutions to the supply chain

    coordination problems in construction and an attribute

    is one of a set of factors that will influence the CSC

    decision-making process. The application of MAUTwill be discussed in the subsequent sections in detail.

    According to Gupta et al. [17], agent technology

    provides a convenient tool to enhance communication

    and coordination in a distributed system to ensure

    efficient decision making. Kwon and Lee [22] also

    believe that MAS, where multiple agents work

    collectively to solve specific interorganization prob-

    lems, provides an effective platform for coordination

    across organizations in the supply chain. This research

    adopts multiagent technology to improve the coordi-

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    nation of CSC decision making. According to the

    definition of MAS, CSC management system is a

    typical MAS. In this kind of MAS, the partners, i.e.,

    general contractor (GC), owner, designer, subcontrac-

    tors, and suppliers are delegated to corresponding

    agents, i.e., GC agent, owner agent, designer agent,

    subcontractor agents, and supplier agents. These agentsare designed and realized in ZEUS, an advanced

    developing environment for distributed multiagent

    systems and has been used to develo p agent-based

    coordination systems in construction [26,29,37,38].

    Multiagent technology is integrated to negotiation and

    multiattribute utility theory in the research. Each agent

    possessing own preferences and utilities autonomously

    negotiates to other agents. Thus, agents can act

    collectively and efficiently as a society and cooperate

    to achieve their own goals as well as the common goals

    of the whole CSC management.

    3. Concepts and problems of CSC

    3.1. The concepts of CSC

    CSC consists of all construction processes, from

    the initial demands by the client/owner, through

    design and construction, to maintenance, replacement

    and eventual demolition of the projects. It also

    consists of organizations involved in the construction

    process, such as client/owner, designer, GC, subcon-tractor, and suppliers. CSC is not only a chain of

    construction businesses with business-to-business

    relationships but also a network of multiple organ-

    izations and relationships, which includes the flow of

    information, the flow of materials, services or

    products, and the flow of funds between owner,

    designer, GC, subcontractors, and suppliers [8,9,39

    41]. According to Muya et al. [42], there are three

    types of CSC: the primary supply chain, which

    delivers the materials that are incorporated into the

    final construction products; the support chain, which

    provides equipment and materials that facilitate

    construction, and the human resource supply chain

    which involves the supply of labor. In this paper, CSC

    is considered from the stage of owner demands to the

    stages of design, construction, and handover. A

    typical model of CSC is shown in Fig. 2. In themodel of CSC, GC is the core of the CSC. And the

    owner and designer are the other two main partners in

    CSC. Excepting the direct suppliers of GC, subcon-

    tractors are also regarded as the suppliers of GC;

    meanwhile, subcontractors have their own suppliers.

    Although a number of researchers have provided

    definitions for CSC management (e.g., Refs. [12,43]),

    for consistency, this research defines CSC manage-

    ment as follows: CSC management is the coordination

    of interorganizations decision making in CSC and the

    integration of key construction business processes and

    key members involved in CSC, including client/

    owner, designer, GC, subcontractors, suppliers, etc.

    CSC management focuses on how firms utilize their

    suppliers processes, technology and capability to

    enhance competitive advantage. It is a management

    philosophy that extends traditional intra-enterprise

    activities by bringing partners together with the

    common goal of optimization and efficiency. CSC

    management emphasizes on long-term, win/win, and

    cooperative relationships between stakeholders in

    systemic perspective. Its ultimate goal is to improve

    construction performance and add client value at lesscost.

    We have identified eight key construction busi-

    ness processes that are implemented within the CSC

    across organizational boundaries. They are: project

    management, client service management, supplier

    relationship management, demand management,

    order fulfillment, construction flow management,

    environment management, and research and develop-

    ment. Fig. 3 presents a schematic view of CSC

    management.

    Fig. 1. Procedure of using MAUT in supply chain coordination in construction.

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    3.2. Problems in CSC

    Although there have been many changes in the

    construction industry as a result of the development of

    technology and culture over the last decades, CSCs do

    not seem to have changed much. Many problems still

    exist in CSC. According to Ref. [40], the major

    problems originate at the interfaces of different

    participants or stages involved in the CSC, as shown

    in Fig. 3. The problems are caused by myopic and

    independent control of the CSC.

    Love et al. [12] and Mohamed [44] noted the

    highly fragmented characteristics of the construction

    industry. For example, the separation of design and

    Fig. 3. Problems in CSC (adapted from Ref. [40]).

    Fig. 2. Model of construction supply chain.

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    construction, lack of coordination and integration

    between various functional disciplines, poor commu-

    nication, etc., are the important impact factors causing

    performance-related problems, such as low produc-tivity, cost and time overrun, conflicts, and disputes.

    Palaneeswaran et al. [11] revealed the weak links in

    CSC as follows:

    ! Adversarial relationships between clients and

    contractors;

    ! Inadequate recognition of the sharing of risks and

    benefits;

    ! Fragmented approaches;

    ! Narrow minded bwin/loseQ attitudes and short-term

    focus;! Power domination and frequent contractual non-

    commitments resulting in adverse performance

    track records with poor quality, conflicts, disputes,

    and claims;

    ! Prime focus on bid prices (with inadequate focus

    on life-cycle costs and ultimate value);

    ! Less transparency coupled with inadequate infor-

    mation exchanges and limited communications;

    ! Minimal or no direct interactions that foster

    sustainable long-term relationships.

    In order to overcome the shortcomings (weak

    links) of CSC and resolve the problems in CSC, and

    to further improve the performance of the whole CSC,

    this research presents a solution which integrates the

    agent technology and multiattribute negotiation tech-

    nology. This solution will be explained in details in

    the following sections.

    4. Design of agent-based framework for supply

    chain coordination

    4.1. Integrated design

    CSC involves multiple agents that delegate

    organizations to autonomously perform tasks

    through exchanging information. It has increasing

    number of participants due to the increasing scale

    and complexity of construction projects. As a

    result, the coordination among the participants

    becomes a challenge that is vital to the perform-

    ance of CSC and the value to the client. These

    require an agent-based framework which has an

    appropriate structure and effective coordination

    mechanism to promote efficient communication

    among all parties. The framework should also bestable, flexible, and user-friendly. Based on these

    considerations, we have designed the framework as

    shown in Fig. 4.

    In this framework, the domain agents include both

    dserviceT agents (i.e., coordinator agent, monitor

    agent, and name server agent) and dspecialtyT agents

    (i.e., owner agent, design agent, GC agent, subcon-

    tractor agents, and supplier agents). The suppliers

    include both GCs suppliers and subcontractors

    suppliers. Here, we assume that all materials and

    human resources are arranged by GC or subcontrac-tors and there are no owners suppliers in this

    framework. All agents communicate and cooperate

    through the Internet.

    All specialty agents advertise their abilities, knowl-

    edge, and preferences in the acquaintance database

    maintained by of the coordinator agent, and their

    addresses in the address book maintained by the name

    server agent. The specialty agents use the coordinator

    agent to identify agents with the required abilities,

    knowledge, and preferences. They also use the name

    server agent to determine the addresses of the

    identified agents.

    The coordinator agent has a mailbox and message

    handler for receiving and responding to queries from

    agents about the abilities and preferences of other

    agents, and an acquaintance database for storing the

    abilities and prefernces of the agents. It functions by

    periodically querying all the agents in the society

    about their abilities and preferences, and storing the

    returned information in its acquaintance database. The

    monitor agent is used to view, analyse societies of

    agents. It functions by querying other agents about its

    states and processes, and then collating and interpret-ing the replies to create an up-to-date model of the

    agents collective behavior. This model can be viewed

    from different perspectives through visualization

    tools. The name server agent provides a look-up

    service for agents addresses and has a mailbox and

    message handler, the component needed for receiving

    and responding to agents requests for the addresses of

    other agents.

    The specialty agents, which are independent and

    autonomous in making decisions, are designed to

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    delegate corresponding behaviors of CSC partici-

    pants. The GC agent stands for GC to perform its

    responsibilities, including cost control, schedule,

    quality, safety, and environment performance of the

    project through coordination with subcontrctors,

    suppliers, owner, and designers. The subcontractor

    agents simulate the decision-making process of

    subcontractors to negotiate with GC and their

    suppliers. The owner agent tracks the real schedule,

    cost, and quality of the project and duly send the

    information of design changes (new demands) to the

    designer agents and the GC agent. The designer

    agents will respond to the demands and send

    information and design change drawings to the

    owner and the GC. The GC agent reschedules the

    project, makes new decisions, and sends the infor-

    mation to subcontractor agents, supplier agents, andowner agent. In the framework, all coordination

    processes are based on multiattribute negotiation

    (bM-NegotiationQ as shown in Fig. 4) between

    sepcialty agents. According to Andreas [45], agent-

    based automated negotiation provides an effective

    mechanism to coordinate the decision-making activ-

    ities in supply chain. The multiattribute negotiation

    mechanism for coordinating the interorganizations

    decsion making in CSC is the significant compo-

    nents of ABS3C. The following section describes the

    design process of the multiattribute negotiation

    mechanism in detail.

    4.2. Multiattribute negotiation model

    Although Kim and Paulson [30] present an agent-

    based compensatory methodology to improve the

    coordination of project schedule changes, it only

    considers the utility of timing and cost and is not

    suitable for the coordination of decision making in

    CSC. We present an agent-based multiattribute

    negotiation model for supply chain coordination in

    construction, which creatively extends the general

    negotiation model for A/E/C [27] from SCM and

    utility theory perspectives and integrates the composi-

    tional multiattribute negotiation model [46], as shown

    in Fig. 5. The model consists of three elements: CSC participants, multiattribute negotiation process, and

    the outcome.

    Each of these elements plays a role in a generic

    coordination problem within the domain. All partic-

    ipants reveal their attributes and preferences in the

    negotiation process with due regard to their parent

    organizations and relationships to the issues. Here,

    each of the CSC participants is represented by a

    corresponding agent in the framework. The outcome

    will be the negotiation results determined by the

    Fig. 4. An agent-based framework for supply chain coordination in construction.

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    interactive process between participants in CSC. The

    multiattribute negotiation process is the interactive

    exchange and elicitation of participants preferences.

    The following section will focus on the negotiation

    process.

    4.3. Multiattribute negotiation process

    According to Jonker and Treur [46], the multi-

    attribute negotiation process includes the following

    five steps:

    (1) Evaluation of the attributes of the initial sol-

    utions made by the participants;

    (2) These evaluations are aggregated into overall

    utilities of these initial solutions;

    (3) Provision of the target utility;

    (4) Based on the target utility and the distribution of

    attributes, the values of the target attributes are

    determined, which lead to a new round of

    decision making;

    (5) For each of the target attributes, an attribute

    value is chosen that has an evaluation value as

    close as possible to the target evaluation value

    for the attribute.

    In the agent-based multiattribute negotiation

    model, these five steps are simplified to three

    processes: attributes evaluation, utility determination,

    and attribute planning.

    4.3.1. Attributes evaluationAs shown in Fig. 5, many attributes are involved in

    the process of supply chain coordination in construc-

    tion. Attributes evaluation is a process whereby the

    value of the attributes are evaluated, based on the

    preferences of the participants in the CSC. All

    attributes are classified into two categories: quantita-

    tive and qualitative. For the quantitative attributes,

    such as cost and time, the value of these attributes can

    be directly calculated according to certain principles.

    For the qualitative attributes, such as quality, safety,

    Fig. 5. Multiattribute negotiation model for supply chain coordination in construction.

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    and environment, it is necessary to construct a scale to

    measure the levels of these attributes. In this paper, a

    scale, from 0 (worst) to 10 (best), serves as the

    measure of the evaluation. The most frequently usedfive levels are: 1worse, 3bad, 5normal, 7

    good, and 9better. When a compromise is needed,

    0, 2, 4, 6, 8, 10 are intermediate values between the

    two adjacent judgments.

    After evaluating the attributes in a table form, an

    evaluation matrix that includes m participants and n

    attributes is obtained:

    X xij

    mn

    where xij is the value of the jth attribute evaluated by

    the ith participant in a decision-making process. Next, the matrix X is translated into a unitary

    normalization matrix of vector:

    Y yij

    mn

    where 0VyijV1, and

    yij xij

    , ffiffiffiffiffiffiffiffiffiffiffiffiffiXmi1

    x2ij

    s

    4.3.2. Utility determination

    In this process, the target utility is determined. The

    utility of the ith participants decision making (Ui) is

    given by

    Ui Xnj1

    wjyij

    Where the wj is the weighting of the jth attributes:

    wj Xnj1

    akj

    0 Xnk1

    Xnj1

    akj

    WherePn

    j1 wj 1 and akj is the value of relativeweightiness between kth attribute and jth attribute.

    The value of akj is given by

    akj 1 ; if kth attribute is more important than jth attribute0:5 ; if kth attribute is important as jth attribute0 ; if kth attribute is less important than jth attribute

    8