Editor's Note

“Modeling a Contractor’s Markup Estimation:” Understanding that the estimation of markup is a difficult process for contractors in a changeable and uncertain construction environment, Liu and Ling construct a fuzzy neural network (FNN) model to assist contractors in making markup decisions. From a survey and interview with local contractors, the factors that affect markup estimation and the rules applied in markup decisions are identified. Application of the model shows that the FNN model will assist contractors in markup estimation with more accurate results.

“Finance-Based Scheduling: Tool to Maximize Project Profit Using Improved GAs:” A contractor’s ability to procure cash to carry out construction operations represents a crucial factor to run a profitable business. Bank overdrafts have always been the major source to finance construction projects. Elazouni and Metwally utilize genetic algorithm (GA) techniques to devise finance-based schedules that maximize profit through minimizing financing costs and indirect costs.

“Impact of Perceived Leadership Styles on Work Outcomes: Case of Building Professionals:” Chen and Chan employ and test Bass’s transformational leadership theory in a sample of professional employees. The study is used to examine the extent of leaders who are perceived to use transformational and transactional leadership styles to identify which of the two leadership styles is best able to predict outcomes of leader effectiveness, extra effort by employees, and employees’ satisfaction with the leaders. The results also offer insight into the management theory for building professionals in business organizations.

“Waste-Based Management in Residential Construction:” The strength of housing construction has a profound effect on the national economy and the society. As a consequence, achieving high productivity, quality, and safety are considered of high priority for this industry segment. Zhang, Eastham, and Bernold propose to replace the traditional management approach for site operation with a management philosophy that aims to eliminate process waste. The authors demonstrate that a waste-based management philosophy creates a culture of continuous improvements and innovative progress.

“Valuing Flexibility in AEC IT Investments:” When investing in IT applications, construction managers implicitly account for the value of adding future applications to the original investment as the business and technical environment changes. A real-option model links uncertainty to the value of an underlying traded asset, providing an objective measure of this managerial flexibility. Ekström and Björnsson explore case studies regarding the value added by extending contractors’ software platforms and draw conclusions based upon the results.

“Embodying Product and Process Flexibility to Cope with Challenging Project Deliveries:” Four factors make it challenging to manage semiconductor fabrication facility projects. Gil, Tommelein, Stout, and Garrett empirically develop a framework that provides a structure for helping to solve the puzzle of which strategies to employ to cope with the challenges. Their framework is comprised of two principles: investing up front in a flexible product design, and structuring a flexible process.

“Computer Simulation Model: Construction Analysis for Highway Rehabilitation Strategies:” The consequences of the serious deterioration of state highways built in the United States during the 1960s and 1970s are high maintenance and have high road-user costs due to degraded road surfaces and construction work zone delays. Lee and Ibbs present a simulation model that estimates the maximum amount of highway rehabilitation∕reconstruction during various closure time frames, balancing project constraints such as scheduling interfaces, pavement materials and design, contractor logistics and resources, and traffic operations.

“Analytic Network Process Applied to Project Selection:” Owing to the complexity of a construction project, the analytic network process is helpful to deal with interdependent relationships within a multicriteria decision-making model. Cheng and Li illustrate how to empirically prioritize a set of projects by using a five-level project selection model. A questionnaire was answered by a group of construction professionals from a medium-sized local developer, and their scores were computed for prioritizing the potential projects.

“CONLIGHT: Lighting Design Model for Nighttime Highway Construction:” The utilization of nighttime work in highway construction and rehabilitation projects has been increasing in recent years. For these projects, construction planners are required to develop and submit a lighting plan that meets specific criteria. In order to support construction planners, El-Rayes and Hyari present a lighting design model that considers the specific requirements of nighttime highway construction operations.

“Time-Cost-Quality Trade-Off Analysis for Highway Construction:” El-Rayes and Kandil present a multiobjective optimization model that supports decision makers in performing the challenging task of finding an optimal resource utilization plan that minimizes construction cost and time while maximizing quality. The model is designed to transform the traditional two-dimensional time-cost trade-off analysis to an advanced three-dimensional time-cost-quality trade-off.

“Field Experiments in Automated Monitoring of Road Construction:” The growing need for better monitoring and control of road construction projects, together with rapid technological progress, have led to a number of interesting developments. Navon and Shpatinitsky describe the development of a real-time monitoring model capable of measuring productivity and progress automatically, using Global Positioning System for on-side automated data collection. The model was tested and validated on-site.

“Use of Trench Boxes for Worker Protection:” Work in trenches can be very dangerous if workers are not provided with adequate protection against cave-ins. Hinze explores the practice of the use of trench boxes to provide such protection. The author draws conclusions upon results of a study of the experiences of utility contractors with the use of trench boxes. The study provides several notable findings that can help in implementing safe work practices in trenches.