WSC 2003 Final Abstracts

A Construction Process Simulation Web Service
Daniel W. Halpin, Henyi Jen, and Jungwuk Kim (Purdue University)

Abstract:
This paper explores the potential of construction process simulation as a web service. This web service, or web based application, exploits the high accessibility characteristic of the web, to support easier information exchange and peer collaboration. Two concepts are discussed and presented. One web based prototype called interactive Simulation System (ISS) allows a user unfamiliar with simulation concepts to evaluate construction process productivity (Kim 2000). A second prototypical web service called Web CYCLONE is built upon CYCLONE (Halpin 1973; Halpin and Riggs 1992) methodology and provides the power of simulation to all user levels, novice or professional. The framework of Web CYCLONE is a three-leveled structure, namely novice, intermediate and advanced level, in that each level caters to user needs depending upon the level of sophistication of the user. An asphalt paving operation simulation model is used to demonstrate each prototypical system.

Building a Virtual Shop Model for Steel Fabrication
Lingguang Song and Simaan M. AbouRizk (University of Alberta)

Abstract:
Steel fabrication is a complex process, which encompasses product uniqueness, a high product mix, and a number of activities involving a variety of equipment and labor disciplines. The steel fabrication industry needs advanced tools and techniques in order to estimate, plan, and control fabrication shops. This paper proposes a system for building virtual fabrication shop models capable of estimating, scheduling, and analyzing production. The system defines conceptual models for product, process, and the fabrication facility itself. It offers tools, such as product modeling, process modeling and planning, and a special purpose facility modeling tool, which allow users to implement these conceptual models. Modeling enhancements have enabled a more accurate modeling of machine and labor productivity, as well as better management of shop production rules. The modeling capability of the developed system is demonstrated through a case study.

Variable-Speed Resource Motion in Animations of Discrete-Event Process Models
Vineet R. Kamat (University of Michigan) and Julio C. Martinez (Virginia Polytechnic Inst. & State University)

Abstract:
This paper presents research that addresses the problem of describing the accurate, variable-speed motion of simulation objects on realistically-shaped trajectories (i.e. paths) in animations of discrete-event simulation models. The work puts in place techniques that modelers can use to instruct virtual simulation objects to follow any arbitrarily-shaped velocity profiles while adhering to fixed motion completion times when traversing along any defined motion path trajectories. A computation scheme that allows simulation models to define the general shapes of relevant velocity profiles and then heuristically scales those profiles to accommodate communicated activity instance durations is presented. While allowing animated simulation objects to be moved with any arbitrarily shaped velocity profiles, this technique ensures that an object’s temporo-spatial control rests entirely with the underlying simulation models.

Impact of Multitasking and Merge bias on Procurement of Complex Equipment
Jan A. Elfving and Iris D. Tommelein (University of California, Berkeley)

Abstract:
This paper describes how multitasking and merge bias may impact the procurement time of complex equipment, such as power distribution equipment used in capital projects. The time required to procure this type of product is often based on past experience and ad hoc assumptions, without explicit consideration for the contributing factors. Capital projects are becoming increasingly complex, requiring more experts to contribute knowledge. By relying on ‘received traditions,’ procurement times are often underestimated thereby creating numerous problems for the project participants downstream in the supply chain. The presented model builds on Sigma, an event scheduling simulation engine, and uses various input scenarios to show how sensitive the procurement time is to the effects of multitasking and merge bias. Insights gained from the simulation may help practitioners to more accurately determine the time required to procure complex equipment and to locate and size time buffers in the procurement process.

An Application of Lean Concepts and Simulation for Drainage Operations Maintenance Crews
Albert Agbulos and Simaan M. AbouRizk (University of Alberta)

Abstract:
The City of Edmonton’s Drainage Operations Branch oversees the inspection, maintenance, and repair of the city’s drainage network of over an area of 700 km² to serve a population of over 600, 000. The maintenance activities consume a large amount of funding and, therefore, are sensitive to any improvement in the maintenance crew’s productivity. The study focused on selected drainage maintenance crews. The application of the industrial engineering philosophy of work measurement, lean production theory, and simulation analysis was used to capture current work methods, generate and test alternative methods, and develop new standards. As an example, this paper will focus on the methodology utilized for the Service Line Rodding maintenance crews.

Agent-Based Modeling and Simulation in Construction
Anil Sawhney and Howard Bashford (Arizona State University), Kenneth Walsh (San Diego State University) and Ajith Rao Mulky (Rensselaer Polytechnic Institute)

Abstract:
Agent-based Modeling and Simulation (ABMS) is a relatively new development that has found extensive use in areas such as social sciences, economics, biology, ecology etc. Can ABMS be effectively used in finding answers to complex construction systems? The focus of this paper is to provide some answers to this question. Initial experimentation is conducted to understand the advantages of using ABMS either in isolation or in combination with traditional simulation methodologies. The paper provides a summary of this experimentation, conclusions and sets the agenda for future research in this area.

Simulation of the Residential Lumber Supply Chain
Kenneth D. Walsh (San Diego State Univesity) and Anil Sawhney and Howard H. Bashford (Arizona State University)

Abstract:
This paper describes the lumber supply chain for a case study of a large homebuilder, extending through multiple tiers from the homebuyer to the lumber company. The builder required its framing subcontractor to accept the risk for lumber cost fluctuations. Under this agreement, the framing subcontractor provided a fixed lumber cost, which could only periodically adjusted. The lumber supply chain leading to the framing subcontractor was found to be of long and variable duration. The function of the builder-framer/lumber yard-lumber company portion of the supply chain was simulated in order to evaluate the cost effectiveness of this strategy, using historical records of lumber prices to model commodity price fluctuations. Based on the simulation results, the risk transfer strategy appears to induce a risk premium generally in excess of the true commodity price risk.

Reasoning about Actions and Events in Situational Simulations
Amlan Mukherjee and Eddy M. Rojas (University of Washington)

Abstract:
In this paper we have applied an interval representation of time to represent and reason about activities, events, actions and situations relevant to the construction domain. The first part of the paper formally defines the situational simulation environment and develops a set of temporal axioms which can be used to 1) Express precedence constraints between time intervals and 2) Capture the causal relationships between actions and events. The second part of the paper looks at an agent reasoning mechanism used to perceive and predict actions and foresee future consequences of present actions within the simulation environment. Agent reasoning is based on awareness derived from a knowledge base of facts which captures the causal nature of events in the construction management domain.

Monte Carlo Simulation for Schedule Risks
Brenda McCabe (University of Toronto)

Abstract:
Research was undertaken to assist practitioners in undertaking Monte Carlo simulation of project schedules. A probabilistic model was developed to translate project characteristics into schedule risk boundaries. This model has been tested in several projects and performed very well. Lessons learned during the application of Monte Carlo simulation to a large project are discussed.