Modeling the Construction Management Process to Support Situational Simulations

Construction managers are decision makers who administer nontrivial processes. The replacement of highly experienced construction managers and other construction professionals is a laborious process for the industry. This paper introduces a conceptual framework for the construction management practice that serves as the foundation for the development of situational simulations. Situational simulations are temporally dynamic clinical exercises with the objective of exposing participants to rapidly unfolding events and the pressure of decision making. The application of situational simulations provides construction managers and other decision makers the opportunity of experiencing and responding to risky events without endangering the success of real projects, further enhancing their decision-making skills. The construction management conceptual framework includes a process, a product, and an information model. The analysis of a basic mathematical representation of the process model is the focus of this paper.     

基于SCM的企业信息系统框架结构研究

从现代企业供应链管理（SCM）的需求出发，结合某合资公司的信息系统设计方案，分析了用于企业供应链管理计算机信息系统的框架结构以及功能设置。建立了一套与之相适应的能准确及时获取外部企业相关数据的新型管理信息系统。本系统采用外托数据管理中心的模式，解决了供应链中的各个企业信息共享的问题，使得供应链具有更大的柔性。因此，采用外托数据管理中心的方式集成的供应链管理系统，是企业实施供应链管理的较优系统集成结构。     

Discrete-Event Simulation-Based Virtual Reality Environments for Construction Operations: Technology Introduction

The next logical evolution of discrete-event simulation (DES) technology for construction is for simulations and animations to run concurrently and in a manner that allows interaction with the animation to affect the course of events in the simulation. This effectively enables the creation of virtual environments with logic based on DES models, something that recent research efforts have made possible. This paper introduces this technology with the help of a case study. In particular, the paper presents how interactivity can improve the process of model validation in simulation studies, which is a critical step in achieving model credibility. Via a complex earthmoving operation, a construction engineer can use real-time interactivity to create situations of interest and study the model’s response to those, and thus validate that the response is appropriate. These capabilities can significantly enhance the process of model validation, thereby adding to the value of DES for practical use in operations planning and design.     

Perceptions of Contractual Risk Allocation in Construction Supply Chains

Common perceptions of contractual risk allocation are the basis of a harmonious, effective and efficient construction project. This paper explores the extent to which common perceptions of risk allocation exist along the construction supply chain. The results of a survey indicate that differing perceptions are worryingly high in all relationships, but particularly further down the supply chain. The paper indicates the relationships in which this is most likely to occur and the types of risk it is most likely to affect. The results provide important lessons for project managers, negotiators and contract drafters. In particular, by providing a better understanding of where and how differences in risk perceptions are likely to emerge, they help those negotiating and drafting contracts focus their energies more effectively to help minimize the potential for unnecessary loss and dispute. Finally, our results indicate that the key to better managing perceptions of risk is fundamentally one of communication, consultation and involvement in contractual decision-making. The key point is that contractual allocations of risk have little meaning if they are separated from the social and behavioral context in which risk is experienced by those involved in a project.     

RISim: Resource-Interacted Simulation Modeling in Construction

Discrete-event simulation is an effective approach to analyze construction operations. However, it is usually time-consuming and knowledge demanding to develop a practical simulation model, and thus not cost-effective due to the uniqueness and relatively short life of construction projects. The capability of discrete-event simulation modeling has not been popularly recognized by site managers until recently. A clear and explicit solution is to simplify and speed up the model development cycle, so as to enable users without much knowledge of simulation technology to easily generate a model in a relatively short period of time. In this paper, a resource-interacted simulation (RISim) modeling approach is presented, which adopts a resource oriented methodology to promote an intuitive feel to simulation modeling. In RISim, an operation is modeled in two abstraction levels—namely, the resource level and process level. An operation is viewed as a collection of resources and their interactions. Complex resources and simple resources are used to respectively represent resources with or without their own processes. The operation logic is mainly represented with internal complex resource flows, which are integrated by simple resource flows between complex resources. Resource flows can be easily conceived by site managers, enabling them to build up the logic naturally and simply. A resource library is used to implement resource reusability. Finally, an example in concrete delivery operation illustrates the methodology of resource-interacted simulation modeling and its potential for “plug-in and simulate.”     

Web-Enabled System Dynamics Model for Error and Change Management on Concurrent Design and Construction Projects

Construction projects are uncertain and complex in nature often because of iterative cycles caused by errors and changes. These errors and changes impair project performance and, consequently, cause schedule and cost overruns to be prevalent. Iterative cycles are more detrimental when design and construction are concurrent and often force activities to proceed without complete information. In an effort to address this issue, this paper presents the information technology aspect of the dynamic planning and control methodology (DPM), which provides a mechanism that will analyze the impact of negative iterative cycles on construction performance. In order to guarantee a smooth application of this method to real-world projects, DPM has been developed by integrating several existing methods around a core system dynamic model for quality and change management and then implementing these methods into a web-based collaborative environment. A case project, applying the developed web-based DPM, shows great potential in facilitating on-site decision making by virtue of its support of data analysis as well as real-time information sharing.     

Strategic Positioning of Inventory to Match Demand in a Capital Projects Supply Chain

Industrial buyers of capital facilities have experienced and continue to experience pressure to reduce facility design and construction lead time. This pressure arises both internally (due to successes in manufacturing lead time reductions) and externally (due to competitive forces including narrowing product delivery windows). This paper presents a case study detailing one owner’s efforts to reduce the length and variability of delivery time for long-lead construction materials in order to improve overall project lead time. The owner adopted a long-term multiproject perspective, procuring material in advance of specific projects and holding it at a position in the supply chain selected to allow flexibility for customization. Reduction in lead time of 75% from order to delivery of the material resulted for individual projects within the owner’s capital plan. As a result, the material was available at the construction site well in advance of its need for erection. To study if holding material at alternative locations in the supply chain could provide a better match between delivery quantities and the demand for erection, the supply chain was simulated. In this case study, demand information was imprecise, allowing only the quantity of material delivered to be considered rather than matching specific items to specific locations. Nonetheless, the results demonstrate the utility of simulation in the capital projects supply chain and the value of improving demand forecasts.     

Ubiquitous Sensor Network for Construction Material Monitoring

Timely acquisition of construction resource information is an essential task for construction engineers and managers. Due to the harsh and dynamic construction environment, it is not easy to acquire construction information in real time. This paper presents a radio frequency identification (RFID) and ZigBee (IEEE 802.15.4)-based system to manage materials on a busy construction site where a data communications system is not in place. RFID tags are attached to and used to identify various kinds of construction materials, and the ZigBee communication technology is used to wirelessly transfer this information. To confirm the viability of our system, the RFID and ZigBee technologies were assessed using an indoor experiment. Following this, a field experiment was then conducted. On a building construction site, a range of construction materials was identified using RFID tags and this information was transferred to an end user with the help of ZigBee multihop networking. The results of the field experiment showed an acceptable reading range and rate for the proposed system. Therefore, the integrated system with RFID and ZigBee modules demonstrated great potential for improving the existing management processes for construction resources on large and complex construction sites.     

Developing a Resource Supply Chain Planning System for Construction Projects

The high variability of construction environments results in high construction-cost variation, especially in material costs. Inadequate planning may cause material shortages that delay the project schedule or, alternatively, a substantial increase in inventory costs by producing or supplying materials earlier than they are needed at the construction site. In order to solve these problems, this paper studies steel rebar production and supply operations and establishes an optimal model that minimizes the integrated inventory cost of the supply chain. Based on the optimal model, this paper develops a decision-support system to generate a production and supply plan for a supplier and buyers of steel rebar. After utilizing the decision-support system to create the supply and production plan, this paper analyzes the results to study the influence of transaction constraints on inventory cost. This paper also discusses cases of global optimization of the inventory cost for the entire supply chain and compares them with cases of local optimization for individual members.     

LEED Implementation Guide for Construction Practitioners

Leadership in Energy and Environmental Design (LEED) is a certification program developed by the U.S. Green Building Council for designing, constructing, and certifying green buildings. This paper presents a LEED implementation guide for construction practitioners to assist them in the certification process. The guide was formulated primarily through input, suggestions, and recommendations received from LEED accredited professionals including architects, engineers, commissioning authorities, general contractors, construction managers, and facility managers. Data were collected through four questionnaire surveys where two of which were used for guide development and the other two for modification and validation. General contractors, construction managers, and engineers can use the LEED implementation guide as a reference for managing their LEED certification process. The proposed guide can also assist owners interested in building a LEED certified facility.     

Multi-Agent Framework for General-Purpose Situational Simulations in the Construction Management Domain

The need for contextually rich education environments in construction management suggests the development of a general-purpose situational simulation framework that can be used by independent developers to build effective training environments. Design and implementation of such a framework involves an understanding of the reasoning processes underlying the construction management domain. These reasoning processes can be isolated using a conceptual classification of problems in the construction management domain into constraint satisfaction and planning. Such a classification allows us to distribute the different reasoning processes to autonomous agents that comprise the foundations of a multi-agent framework for building general-purpose situational simulations. The Virtual Coach is an implementation of the proposed framework. Experimental results from preliminary studies have shown the efficacy of the Virtual Coach as an educational tool.     

Materials Handling System Simulation in Precast Viaduct Construction: Modeling, Analysis, and Implementation

The interactive, complicated system environment of a construction site renders conventional site layout planning and scheduling techniques to be inadequate in coping with materials handling system design in construction. In this paper, we present a university-industry joint endeavor for improving the effectiveness of the materials handling system on a precast viaduct construction project in Hong Kong by implementing the simplified discrete-event simulation approach (SDESA) along with its computer platform resulting from recent research. How to apply the simulation methodology of SDESA is elaborated step by step. Particular emphasis is placed on procedures of establishing a simulation model, validation of the simulation model, design of simulation experiments, and analysis of simulation results. With process flowchart, site layout plan, and process animation produced in a view-centric simulation environment, it is straightforward to establish, validate, and communicate the operations simulation. The research team convinced the project director, as well as field managers, of the functionality and effectiveness of operations simulation. The knowledge derived from simulation added to experiences of site managers in materials handling system design. With the aid of simulation, even junior engineers would be capable and confident to draw up an actionable construction plan that would lead to enhancement of cost effectiveness and productivity in the field.     

Automated Generation of Work Spaces Required by Construction Activities

To provide a safe and productive environment, project managers need to plan for the work spaces required by construction activities. Work space planning involves representing various types of spaces required by construction activities in three dimensions and across time. Since a construction schedule consists of hundreds of activities requiring multiple types of spaces, it is practically impossible to expect project managers to specify manually the spatiotemporal data necessary to represent work spaces in four dimensions. This paper presents mechanisms that automatically generate project-specific work spaces from a generic work space ontology and a project-specific IFC (industry foundation class) based 4D production model. The generation of these work spaces leads to a space-loaded production model. Within this model, work spaces are represented as being related to the relevant construction activities and methods and as having attributes that describe when, where, and how long they exist, and how much volume they occupy. These space-loaded production models enable richer 4D CAD simulations, time-space conflict analysis, and proactive work space planning prior to construction.     

Exponential, Gamma, and Power Law Distributions in Information Flow on a Construction Site

This paper examines the statistical distributions of interarrival and response times for construction-site correspondence. Data from a number of construction projects are analyzed and hypotheses are proposed and tested to link the probability distribution to the type of correspondence. Although the commonly assumed exponential distribution of interarrival times is found to be accurate for all types of correspondence, the response times for different types of correspondence follow different distributions depending on the type of correspondence. In particular, a power law relationship is observed between incidence frequency and response time for requests for information. Knowing the statistical distributions for a class of events helps managers forecast future work and manage risk. Simulation models used by practitioners and researchers for various project management goals are also improved by incorporating appropriate statistical distributions for generating various events.     

Reliability Buffering for Construction Projects

Buffering is a common practice in project planning. Project managers or schedulers have used a time contingency to guarantee the completion time of either an activity or a project. This traditional buffering, however, often fails to protect the project schedule performance, resulting in an unnecessary resource idle time. To deal with this problem, reliability buffering, a simulation-based buffering strategy, is presented. Reliability buffering aims to generate a robust construction plan that protects against uncertainties by reducing the potential impact of construction changes. The effectiveness of reliability buffering is examined by simulating a dynamic project model that integrates the simulation approach with the network scheduling approach. The research results indicate that reliability buffering can help achieve a shorter project duration without driving up costs by pooling, resizing, relocating, and recharacterizing contingency buffers. A case study of bridge construction projects also demonstrates how construction projects can benefit from reliability buffering in real world settings. Although further validation is needed, reliability buffering can potentially impact the planning and control of construction projects by improving the consideration of construction feedbacks and characteristics in buffering, and serving as an input to a dynamic project model.     

Knowledge Mining of Information Sources for Research in Construction Management

Extracting the right information at the right time is vital in any research project. Moreover, researchers generally seek innovative “knowledge mining” techniques for optimizing their research efforts within constrained time frames and with scarce resources. Meanwhile, rapid developments in the fields of computing and information technology drive the accelerated globalization process in both industry and academia. This paper explores some of the emerging technologies and associated research methodologies from an information supply chain perspective. An application in a recent Internet based two-phase questionnaire survey for design/build contractor selection provides a useful case study in the structuring of an innovative knowledge mining strategy. This experience feeds into the formulation of a “high-velocity” knowledge mining framework and a set of guidelines—to facilitate and enhance such innovative construction management research, while dealing with some initial issues/problems in the Internet based research environment. Furthermore, some critical success factors, key performance indicators, and mining strategies are consolidated for marshalling both vivid and tacit knowledge sources, such as by “exploiting” Internet resources for more creative and efficient construction management research.     

Iconic Animation for Activity-based Construction Simulation

This paper discusses the development of an animation tool for the activity-based construction (ABC) modeling and simulation system. The tool uses an activity-based network diagram, i.e., ABC simulation model, as the animation background image, and uses precreated two-dimensional (2D) iconic images for simulation entities (e.g., resources). The animation process displays the queuing status and dynamic movements of 2D iconic images on the background. It also distinguishes active and idle states of resources and activities. Dynamic reports are available for selected activities with graphs including the production rate and utilization of involved resources. From visualizing the change of status of a simulation process and dynamic interaction between simulation entities in the process, the user can better understand the dynamic nature of the construction process. Animation provides an avenue to demonstrate how dynamic operations are simulated. It also provides an effective tool for the user to verify a simulation model and to validate the obtained simulation results. Compared to other systems, the ABC animation does not require any extra effort in addition to the ABC simulation model constructed for simulation purposes. Therefore, the presented technology greatly reduces the time and cost for achieving animation. A variety of useful information can be observed through animation, and is illustrated using two construction examples.     

Resource Management in Construction

Resource plannirtg and management is one of the most important ingredients for competitiveness and profitability in today's construction industry. In order to control costs, equipment and labor should be utilized in the most efficient way possible. This can be achieved by minimizing the total cost of leased resources under the constraint of maximum and most efficient use of owned equipment and contracted labor force. This paper presents a mixed‐integer linear programming model for the management of resources throughout the project life. Based on the Critical Path Method time analysis, the model derives the schedule for equipment rentals and transient resources, as well as the utilization scheme for owned equipment and other available resources. The model can be used as an estimating tool for multi‐project resource planning and sharing, and as a means to implement the most efficient utilization of resources throughout the duration of the whole project.     

Neurofuzzy Genetic System for Selection of Construction Project Managers

Choosing a project manager for a construction project—particularly, large projects—is a critical project decision. The selection process involves different criteria and should be in accordance with company policies and project specifications. Traditionally, potential candidates are interviewed and the most qualified are selected in compliance with company priorities and project conditions. Precise computing models that could take various candidates’ information into consideration and then pinpoint the most qualified person with a high degree of accuracy would be beneficial. On the basis of the opinions of experienced construction company managers, this paper, through presenting a fuzzy system, identifies the important criteria in selecting a project manager. The proposed fuzzy system is based on IF-THEN rules; a genetic algorithm improves the overall accuracy as well as the functions used by the fuzzy system to make initial estimates of the cluster centers for fuzzy c-means clustering. Moreover, a back-propagation neutral network method was used to train the system. The optimal measures of the inference parameters were identified by calculating the system’s output error and propagating this error within the system. After specifying the system parameters, the membership function parameters—which by means of clustering and projection were approximated—were tuned with the genetic algorithm. Results from this system in selecting project managers show its high capability in making high-quality personnel predictions.