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This paper aims to analyze the urban human settlements of 21 megacities and supercities from 2011 to 2020 in China and improve urban human settlements planning and management. First, the data envelopment analysis (DEA)–Malmquist–Tobit model is used to conduct a static and dynamic evaluation of the efficiency of urban human settlements and analyze the main factors that affect it. Then, the coupling coordination degree model is utilized to quantitatively evaluate the coupling coordination degree between urban human settlements and high-quality economic development. Finally, the GM (1, 1) model is established to predict each city's average input–output index during the 14th Five-Year Plan period. It is hoped that this paper could promote sustainable urban development. The empirical results are as follows: (1) the technical efficiency (TE) from CRS DEA of human settlements in China's megacities and supercities is low. Management and technology are the shortcomings in the development of urban human settlements; (2) total factor productivity (TFP) has shown negative growth. Technical progress efficiency (TC) is the key to improving the efficiency of urban human settlements; (3) urban infrastructure has the most significant role when promoting the efficiency of urban human settlements; (4) the coupling degree between the efficiency of human settlements and high-quality economic development is mainly high-level coupling. The degree of coordination is gradually rising; and (5) during the 14th Five-Year Plan period, the investment in human settlements in both types of cities will continue to increase. With the continuous expansion of investment, the output will be imbalanced. [ABSTRACT FROM AUTHOR]

Construction firms in developing economies have started to explore the global market. However, whether internationalization can improve their productivity growth in the long run needs to be considered. Moreover, rapid changes in institutional environments and different ownership concentrations in developing economies can contribute to different outcomes. This study established models that examine the impact of internationalization on total factor productivity (TFP), TFP's components, and the profitability of 86 construction firms in Malaysia from 2003 to 2016 by applying the generalized method of moments (GMM) estimator. The results showed that internationalization reduced firm productivity during Malaysia's lack of promarket phase of 2003–2009 but became negligible during the more promarket phase of 2010–2016. The negative impact was due to scale inefficiency. The effect of regulatory control and family ownership concentration reduced the negative impact of internationalization, whereas capital availability, foreign debt, price control freedom, and government ownership negatively affected the impact of internationalization on firm productivity. This study is the first to explore the impact of internationalization on TFP's components. It contributes to management in the engineering domain by extending insights into the effect of institutional environments, institutional dimensions, and ownership concentrations on the impact of internationalization on firm productivity. [ABSTRACT FROM AUTHOR]

Among mass transportation facilities, high-speed rail systems not only connect major cities but they also drastically shorten the transportation time. The high-speed train maintenance works are an important part of the safety operation system. Also, the reasonable planning and maintenance works execution can ensure the safe running of trains, improve the quality of operation, and reduce company costs. The regular maintenance is a critical element for providing an excellent transportation service to the public. The present study uses data envelopment analysis (DEA) and the Malmquist productivity index (MPI) to analyze the multiyear trends in productivity for the yearly and midterm maintenance efficiencies of 12 high-speed trains in Taiwan. These features are evaluated through systems thinking, and suggestions are offered towards improving those factors responsible for the inefficiency. The results show that eight of the trains studied had attained satisfactory maintenance efficiency, whereas four could be improved, yielding a productivity of 66.7%. In addition, by following the trends in the MPI values, it was found that the technical efficiency (TE) and the total factor productivity (TFP) are the main factors responsible for stalling maintenance performance, contributing a decline of 37.1% and 37.7%, respectively. Our study has identified three factors leading to maintenance inefficiency. These three factors are: (1) a change in the scope of the contract, (2) a change of work methods, and (3) a lack of effective communication between the management and the customer. It is hoped that this research can provide useful information that will allow decision-makers to avoid erroneous decisions caused by poor intuitive judgment or inadequate considerations, and to formulate correct policies, to improve maintenance productivity, and to ensure that trains can continue to run safely. [ABSTRACT FROM AUTHOR]

Off-site construction methods have been suggested as a necessity for improving the efficiency and productivity of the construction industry through implementation of automation and lean principles in a controlled factory environment, known as modern methods of construction (MMC). The products and the project delivery and management strategies of off-site construction were studied through a multifaceted qualitative exploration of the off-site timber management strategies of 10 manufacturers, including three UK panel, three UK volumetric, and four European (EU) volumetric timber manufacturers. A comparative productivity analysis was carried out and its sensitivities were analyzed, which led to the conclusion that the labor productivity of the surveyed UK panelized and EU volumetric manufacturers was comparable, but the UK volumetric manufacturers' productivity was lower. As a result, the level of automation and the lean and Design for risassembly (DfD) applications of the manufacturers were all explored to understand these productivity differences within the context of current market trends. [ABSTRACT FROM AUTHOR]

The application of computer vision (CV) in construction projects has been investigated for many years, resulting in several advanced algorithms and methods. However, there is still a need to advance the current methods for improving the productivity of operations and safety on job sites. The excavator is one of the highly used pieces of equipment on construction sites that needs to be monitored to evaluate both safety and productivity. Knowing the productivity of excavators helps to plan the excavation process more accurately. A long queue of trucks waiting for the excavator(s) means paying more money while the trucks are not being loaded. Moreover, excavators have a higher risk of accidents due to their articulated shape compared to other excavation-related equipment. On the other hand, monitoring an object with four degrees of freedom using sensory data is a very difficult task. Therefore, this research investigates the opportunities to fuse CV-based methods and real-time location systems (RTLSs) and apply stereo vision methods to formulate a comprehensive framework for estimating the three-dimensional (3D) poses of excavators as some of the most widely used equipment on construction sites. Instead of using specialized tools, such as off-the-shelf stereo cameras or markers, this study evaluates the applicability of using the surveillance cameras on construction sites as stereo cameras. Moreover, RTLS data and two or more cameras' data are fused by synchronizing the time and coordinate systems of the cameras and RTLS to investigate the potential of enhancing the accuracy of the pose estimation system and reducing the computational load. Finally, the performance of the proposed framework is evaluated by integrating the results of the excavator parts' detection, the backgrounds' subtraction, and the twodimensional (2D) skeletons' extraction of the parts from each camera's view. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine the degree of productivity change in the construction industry and relate these changes to variations in the business cycle. The activity of Spanish firms engaged in the construction of buildings, civil engineering, and specialized activities during the 2000s is used as a case study. Productivity change is estimated by creating a bilateral index using data envelopment analysis, complemented with bootstrapping. The results showed that Spanish firms in building construction experienced a fall in productivity because of a decline in technical and scale efficiencies, despite improvements in technology. The productivity change in civil engineering and specialized construction also was negative; however, the source of this decline was technical regress and negative scale efficiency change, although efficiency change and technology scale change contributed positively. The results further revealed that the firms reacted to the financial crisis of the late 2000s by introducing technological change, although the productive, technical, and scale efficiency changes all were negatively impacted during the economic downturn, suggesting an underuse of resources. This research contributes to the body of knowledge by being the first to analyze the impact of fluctuations in business cycles caused by the 2008 economic crisis on the productivity growth of construction firms representing three construction sectors, and by measuring productivity growth from a multidimensional perspective. [ABSTRACT FROM AUTHOR]

The Chinese construction sector is one of the largest in the world, but the nation's 31 provinces, autonomous regions, and municipalities (hereafter 'provinces' for simplicity) have experienced varying levels of economic development. It is important for stakeholders to truly understand Chinese construction sector efficiency and these disparities. Considering it a more robust approach, this study uses the Färe-Primont data envelopment analysis (DEA) method to estimate construction productivity and efficiency across China from 1995 to 2012. A general finding is that construction productivity in China has experienced incredible growth from a low base in 1995, with eastern China the most productive region and northern China the least. The most productive provinces were Zhejiang, Hunan, and Jiangsu; contradicting conventional wisdom, the least productive were Beijing, Shanghai, and Guangdong. Decomposing the productivity further, it is found that China's construction industry appears to be more scale-efficient than technically efficient. In other words, the industry is operating at an optimal scale for productivity but relies less on technological advancement. This research provides significant insights for understanding productivity of the world's largest construction market in a different perspective. The Färe-Primont DEA method appears to be an effective means of probing industry efficiency from different perspectives, and enables development of evidence-based policies targeted at improved construction productivity in particular regions or provinces. [ABSTRACT FROM AUTHOR]

In addressing the need to ensure not only rigor but also relevance (i.e., practical and socially applicable) in research, this paper provides the knowledge required to understand how to intervene in construction and initiate change that satisfies the need to learn and engender process improvement. In addressing the need to ensure relevance for practice, this paper examines how the 6Es collective learning framework (engaging authentic leadership, enacting coaching, engendering a learning climate enacting behaviors, embedding collective learning, and engaging a new culture) can be operationalized. In doing so, the concept of zero vision (i.e., defects and harm) that is aligned with the notion of error prevention (i.e., errors can be and should be prevented) is challenged and an alternative emphasis on error management (i.e., errors happen) is promulgated; the managerial implications of adopting this approach are discussed as well. The paper concludes that if the construction industry is to gain traction in the pursuit of productivity and performance improvements, then greater emphasis needs to be placed on developing a learning culture that is able to transform error events into experiences; Learning from errors that have occurred (error management) can then help to prevent errors in the future. [ABSTRACT FROM AUTHOR]

Productivity and project performance can be improved through implementing best practices. This paper describes the development of a best productivity practices implementation index (BPPII) for infrastructure projects. The index is a checklist of practices that are considered to have a positive influence on labor productivity at the project level for infrastructure projects. These practices have been grouped together into a formalized set of categories, sections, and elements. Each practice and its planning and implementation levels were defined and assigned a relative weight on the basis of its importance in affecting labor productivity. The productivity factor (PF), defined as a ratio of estimated productivity and actual productivity, was used as a metric to collect information about labor productivity to validate the accuracy of the BPPII for infrastructure projects. Data were collected for infrastructure projects in regards to their planning and implementation level of practices in addition to their PF and project schedule performance. The statistical tests confirmed that the higher implementation of best practices as defined in the index have a strong positive relationship with the PF and project schedule performance. Projects that have a high level of implementation of practices experienced better productivity and schedule performance than those having low implementation. This research contributes new insight into the relationships between sets of practices and project performance as well as a tool for planning practice implementation on infrastructure projects. [ABSTRACT FROM AUTHOR]

Innovation has been regarded as a means of improving performance in construction. Despite its benefits, management of innovation is a difficult task and its measurement is complicated. A comprehensive model comprising interrelated components of construction innovation has not yet been developed and tested. The major objective of this research is to propose a framework to analyze construction innovation. In this respect, a total of 38 factors associated with innovation are identified and grouped under six components, namely the drivers, barriers, enablers, inputs, project-level benefits, and firm-level benefits. The interrelations among these components are examined through a questionnaire survey. Data collected from 110 projects were analyzed using structural equation modeling. The findings of the study suggest that the innovation decision is governed by those factors specified as the drivers; investment in innovation results not only in project-level but also firm-level outcomes; however, the hypothesized negative impact of barriers has not been found to be significant. The findings also reveal that innovation has major benefits such as increases in productivity and client satisfaction at the project level, improvement of company image, improvement of technical and managerial capability, and gaining experience at the firm-level. Research findings are expected to help project managers in construction business devise proper strategies to effectively implement innovation. [ABSTRACT FROM AUTHOR]

The construction industry is beginning to utilize building information modeling (BIM), benefiting from the improved visualization and productivity, better coordination of construction drawings, building documents that contain embedded links to virtual information, faster delivery, and lower costs. However, construction companies often find it challenging to reorganize their company's organizational structure to take full advantage of these benefits of BIM adoption and implementation. This study explores contractors' transformation strategies that will enable them to successfully adopt and implement BIM for major construction projects. In-depth case studies from large contractors capture the benefits of BIM implementation, the appropriate organizational structure, the training and education program, the cost related to BIM implementation, including software and hardware investment, the relationship with other stakeholders, and the future recommendations to implement BIM for their construction projects. This study provides an overall framework and organizational transformation strategies for contractors trying to adopt BIM to maximize the potential benefits achieved in their projects and organizations. [ABSTRACT FROM AUTHOR]

The assessment of the productivity growth of ports is essential to improve their performance and competitiveness. Although there are several nonparametric methodologies to compute the productivity change, the Hicks-Moorsteen productivity index is the only multiplicatively completed index that can be computed without price data. For the first time, the total factor productivity (TFP) change of a sample of ports is evaluated. The analysis covers the 28 ports comprising the Spanish port system, using data over the period 2005-2012. The drivers of TFP--technical change, technical efficiency, mix efficiency, and residual scale efficiency--are also investigated. The results indicate that from 2005 to 2009, the TFP declined significantly owing to the technical change, whereas from 2009 to 2012, the TFP improved significantly. The TFP decomposition illustrates that 10 out of the 28 ports improved their technical change, and 9 out of the 28 ports increased their efficiency change. From a policy and managerial perspective, this study illustrates the importance of separating TFP change into the technical-change and efficiency-change components. [ABSTRACT FROM AUTHOR]

Variations in labor productivity are the result of multiple influential factors. This paper attempts to develop a labor productivity model based on multilayer feedforward neural networks trained with a backpropagation algorithm by which complex mapping of factors to labor productivity is performed. To prevent networks from overfitting and improve their generalization, early stopping and Bayesian regularization are implemented and compared. The results proved a better prediction performance for Bayesian regularization than early stopping. To demonstrate the prediction performance of the presented models, the developed models are implemented at two real power plant construction projects. Moreover, in order to extract the influence rate of each factor on the predictive behavior of the neural network models and to identify the most influential factors a sensitivity analysis is conducted. This paper focuses on the work involved in installing the concrete foundations of gas, steam, and combined cycle power plant construction projects in the developing country of Iran. This study contributes to the construction project management body of knowledge by investigating the influential factors on labor productivity and developing an artificial neural network to measure and predict labor productivity in developing countries using the Bayesian regularization and early stopping methods. This approach provides insight into better ways of modeling labor productivity. [ABSTRACT FROM AUTHOR]

The potential benefits of using off-site production in residential construction have been highlighted in many studies, but the full potential of off-site production approaches is not always realized. This shortfall can be explained by the mismatch between market requirements and the output offered by the production system; in other words, a mismatch between the degree of product standardization and the design of the production system. This mismatch could be resolved through a classification matrix that aids decision makers in matching market requirements and the degree of product standardization with the degree of off-site production and production system design. This paper describes the development of a classification matrix that guides the decision-making process during the designing of new, or redesigning of existing, production systems in residential construction. An important aspect of the development was balancing the trade-off between productivity and flexibility so that products can be produced competitively. The merits of the classification matrix are exemplified by five case companies with different approaches to industrialization and off-site production. The main contribution is the classification matrix per se that reflects different production systems' strengths and weaknesses and thereby aids managers in balancing the productivity-flexibility trade-off to be able to meet the market requirements in the most profitable way. The matrix also supports researchers in analyzing and comparing different production systems used for producing residential buildings. [ABSTRACT FROM AUTHOR]

Successful performance measurement criteria cannot be limited to meeting just the three traditional criteria. Satisfaction is a subjective and critical measurement for the stakeholder performance, but it has rarely been used as a criterion for the performance measurement of project stakeholders. The purpose of this paper is to establish the client and customer satisfaction criteria as the two key stakeholders in construction project for the issue of performance measurement based on the reviewed data. The methodology of this study is based on comprehensive literature review of performance measurements for client and customer whereby the data were analyzed, using the metrics which are the aggregate number of each customer and client-satisfaction criteria occurring in previous study. From the metric analysis, the common factors for customer and client satisfaction were ranked. From the analysis, it can be concluded that expectation and perception are the two common critical satisfaction criteria for client and customer that must be considered where the satisfaction is required. [ABSTRACT FROM AUTHOR]

The North American construction industry has seen a decline in productivity for decades due to underlying problems such as lack of team collaboration, less initial design input, and higher building systems complexity. These problems are most visible in labor-intensive trades, such as mechanical contractors. Within the last decade, building information modeling (BIM) has emerged as a potential solution to these problems. This paper highlights the state of BIM practice in the mechanical construction industry. Through an extensive survey and interview process, this research resulted in three key outcomes. The first is that 58% of mechanical contractors have less than three years of BIM experience and consider themselves as beginners in the use of BIM. Second, BIM implementation cost for these contractors is 1% to 2% of their total project cost estimate. Third, more than 70% of mechanical contractors agree that BIM reduces field conflicts and improves coordination. These factors can assist mechanical contractors allocate proper resources for BIM implementation in their projects to reduce problems. [ABSTRACT FROM AUTHOR]

Environmental issues are considered increasingly more important in the field of industrial production, especially in the early stages of the planning processes: Eco-industrial parks seem to be effective planning models to reduce environmental impact and to increase firm competitiveness at the same time. By describing the Raibano industrial area planning process, this paper investigates the opportunities offered by strategic environmental assessment as an effective and suitable method in developing real eco-industrial parks. The assessment procedure, also supported by some prediction models, has been implemented by considering the environmental effects generated by the industrial park development and use on every environmental component, and the consequent precondition, mitigation, and remediation measures. The illustrated case shows that the application of environmental assessment principles to an early decision-making level enables the enhancement of some key features of eco-industrial parks, such as the high degree of project preplanning and design and the presence of site management and monitoring mechanisms during its implementation, thus guaranteeing enough flexibility to give birth to spontaneous cooperation and exchanges between the industrial activities. [ABSTRACT FROM AUTHOR]

Construction work involves significant physical, mental, and temporal demands. High task demands increase the likelihood of errors, with implications for rework, safety, and productivity. To ensure the safety and productive efficiency of workers, it is important to better understand the task demands and manage them effectively. This exploratory study investigated the task demands in masonry work, the factors that generate the demands, the influence of demands on performance, and the practices that field supervisors use to manage/regulate them. Data were collected on two masonry projects. The NASA Task Load Index (TLX) was used to measure the workers' subjective assessment of task demands. The members of masonry crews perceived different type and level of task demands depending on their role-supervisor, masons, laborers, and operator. Interviews with the crew members identified design features and work practices that influenced the task demands. Extensive field observations identified three strategies that field supervisors use to manage task demands: (1) matching task demands with capabilities; (2) reducing temporal demands; and (3) shifting task demands between roles. Finally, data were collected on performance problems with emphasis on delays, mistakes, rework, and safety incidents. Rework often involved higher task demands and hazards than the normal tasks. The study contributes to practice by identifying factors that increase the task demands of masonry activities and that need to be managed to improve performance. In terms of research, the study identifies and measures the multiple task demands for the different masonry crew roles, identifies sources of task demands, and strategies to manage them. [ABSTRACT FROM AUTHOR]

Scrapers have established an important position in the earthmoving field as they are independently capable of accomplishing an earthmoving operation. Given that loading a scraper to its capacity does not entail its maximum production, optimizing the scraper's loading time is an essential prerequisite for successful operations management. The relevant literature addresses the loading time optimization through a graphical method that is founded on the invalid assumption that the hauling time is independent of the load time. To correct this, a new algorithmic optimization method that incorporates the golden section search and the bisection algorithm is proposed. Comparison of the results derived from the proposed and the existing method demonstrates that the latter entails the systematic needless prolongation of the loading stage thus resulting in reduced hourly production and increased cost. Therefore, the proposed method achieves an improved modeling of scraper earthmoving operations and contributes toward a more efficient cost management. [ABSTRACT FROM AUTHOR]

Americans with Disabilities Act (ADA) paratransit systems are dial-a-ride services that provide public transportation to disabled customers. In large metropolitan areas, these services might use zoning strategies to simplify their management. The objective of this paper is to provide a more in-depth evaluation and comparison between centralized and decentralized zoning strategies. This is achieved by developing a simulation model to evaluate the effects of zoning strategies on the productivity and quality of service for the particular ADA paratransit service, using actual demand data from the city of Houston. Four decentralized zoning strategies are compared with a centralized no-zoning strategy. Higher degrees of decentralization degrade the operational efficiency in terms of larger fleet size because the causative empty trip kilometers are greater. The intrazonal trip percentages of demand and productivity are positively correlated. [ABSTRACT FROM AUTHOR]

The execution of daily construction tasks exposes workers to one or multiple ergonomic risk factors (awkward postures, static force, vibration, repetition, environmental risk, contact stress) and thus varying risks of developing musculoskeletal disorders. As a result, musculoskeletal disorders are common issues in construction and result in costly delays and disability claims. Though there is recent research investigating the epidemiology and causal factors for musculoskeletal injury, the construction industry has not fully embraced this as part of its safety practices. This study presents state-of-the-art ergonomic techniques, Canadian ergonomic legislation, and work-related musculoskeletal disorder (WRMSD) lost-time claims (LTC) statistics to show the resultant economic (cash and productivity) losses and adverse social (occupational health and safety) impact of WRMSDs resulting from current practice and legislation. The potential short- and long-term productivity and cost merits of incorporating ergonomic assessments for construction tasks are presented. [ABSTRACT FROM AUTHOR]

Off-site construction has become increasingly popular in industrial construction projects over the past decade due to its advantages: higher productivity, better quality, better safety, and improved time and cost effectiveness. The fast-paced nature of off-site construction environments and the constraints induced by the construction site, along with the existing limitations within the shop, make the control process of off-site construction quite challenging. High-quality real-time data provided by utilizing new technologies can significantly improve and speed up the process of monitoring projects and identifying possible deviations; however, to be effective, decisions on corrective measures have to be made as quickly as possible. This paper presents an enhanced method based on the control theory concept for taking timely corrective actions to control the dynamic and fast-paced environments of off-site construction shops. The proposed method allows project managers to perform punctual nonlinear data analysis and predict the behavior of the performance of the shop. This leads to promptly determining the best corrective action in the case of variance to achieve a desired performance level with minimum cost. To illustrate its feasibility and potential for improving project control, the proposed approach was successfully implemented in an actual off-site structural steel fabrication shop. [ABSTRACT FROM AUTHOR]

The measurement system configuration is an important task in structural health monitoring in that decisions influence the performance of monitoring systems. This task is generally performed using only engineering judgment and experience. Such an approach may result in either a large amount of redundant data and high data-interpretation costs, or insufficient data leading to ambiguous interpretations. This paper presents a systematic approach to configure measurement systems where static measurement data are interpreted for damage detection using model-free (non-physics-based) methods. The proposed approach provides decision support for the following two tasks: (1) determining the appropriate number of sensors to be employed and (2) placing the sensors at the most informative locations. The first task involves evaluating the performance of the measurement systems in terms of the number of sensors. Using a given number of sensors, the second task involves configuring a measurement system by identifying the most informative sensor locations. The locations are identified based on three criteria; i.e., the number of nondetectable damage scenarios, the average time to detection, and the damage detectability. A multiobjective optimization is thus carried out leading to a set of nondominated solutions. To select the best compromise solution in this set, two multicriteria decision-making methods, Pareto-Edgeworth-Grierson multicriteria decision making and the preference ranking organization method for enrichment evaluation, are employed. A railway truss bridge in Zangenberg, Germany, is used as a case study to illustrate the applicability of the proposed approach. The measurement systems are configured for situations where measurement data are interpreted using two model-free methods; i.e., moving principal component analysis and robust regression analysis. The results demonstrate that the proposed approach is able to provide engineers with decision support for configuring measurement systems based on the data-interpretation methods used for damage detection. The approach is also able to accommodate the simultaneous use of several model-free data-interpretation methods. It is also concluded that the number of nondetectable scenarios, the average time to detection, and the damage detectability are useful metrics for evaluating the performance of measurement systems when data are interpreted using model-free methods. [ABSTRACT FROM AUTHOR]

Construction productivity improvement has become a key area of focus among academia and industry over the last decade attributable to its strong potential in benefitting the construction industry. Despite its high impact on the construction industry, productivity improvement is still an area in which much research work needs to be done to explore its true potential in a practical industry context. Today's construction industry seems to adopt productivity improvement initiatives to gain a competitive edge in the global market place; however, systematization of these approaches is still an area of concern. This paper discusses a framework for the implementation of productivity improvement activities on a construction site, making the process more systematic, accountable, and sustainable with the creation of the construction productivity improvement officer (CPIO), a dedicated position, on construction sites. [ABSTRACT FROM AUTHOR]

The main difference between the Last Planner production control system developed by Ballard and classical control systems is the way in which projects are controlled and planned. The Last Planner system focuses on controlling production units, workflows, and the quality of the performed work. It also permits the identification of the causes for the noncompletion of planned work and decision making in accordance with the project requirements so that actions are timely and productivity is increased. The objective of this paper is to present the results obtained from implementing the Last Planner system in the construction department of a chemical company. In this department, an information flow problem was detected among its members, in which supervisors lacked knowledge about the work to be performed until the project had been perfectly designed. This problem often led to long delays in the projects. The results from the Last Planner system implementation show that identifying the constraints of the planned work leads to an improvement in the percentage and quality of completed activities. [ABSTRACT FROM AUTHOR]

Materials tracking and locating, which can be accomplished through various technologies and data sources, are key elements affecting construction productivity. The need for developing fundamental methods to take advantage of the relative strengths of each technology and data source while dealing with their limitations motivates the development in this paper of data fusion methods for improving materials location estimation. Particular attention is paid to situations in a construction environment in which radio-frequency identification (RFID) tags are attached to each piece of material, and the materials may be repeatedly moved around the site. The construction dynamics, the high noise ratio, and the limitations of the utilized sensing systems result in imperfect data that is imprecise and uncertain. A key challenge is using this imperfect data to improve accuracy and precision while maintaining cost-effectiveness and scalability. To address this issue, a hybrid data-fusion method was developed to increase confidence, accuracy and precision, and add robustness to measurement estimates. This hybrid method leverages evidential belief reasoning and soft computing techniques. The experimental results show that the hybrid fusion method outperforms the traditional methods in data fusion for location estimation. This study has successfully addressed the challenges of fusing data from a range of simple to complex sensor sources within a very noisy and dynamic construction environment. The results presented in this paper indicate that the proposed method has the potential to improve location estimation and to be robust to measurement noise and future advances in technology. [ABSTRACT FROM AUTHOR]

This paper serves as a resource to prefabricated construction managers who are attempting to implement lean thinking to improve their production operations by eliminating waste. Lean is both a general way of thinking and a specific production management approach that emphasizes using less of everything to satisfy the customer by delivering the highest quality at the lowest cost in the shortest time. While providing an overview of lean principles, this paper focuses on two fundamental lean concepts, standardization and continuous flow. To develop these concepts, this paper uses a case-study approach to describe the experiences of a large homebuilder confronted by rising production costs as they migrate wall-building operations from the construction site into a factory. Lean production principles are successfully applied, yielding a 47% increase in productivity and a 25% reduction in lead time. This study also found employee involvement and the supplier relationship as key factors for successful lean implementation. Challenges that limited implementation success and the related lessons learned are also presented. [ABSTRACT FROM AUTHOR]

Absorptive capacity is a firm's ability to value, assimilate, and utilize new external knowledge and apply it to commercial ends. Much of the prior research on absorptive capacity focuses on characterizing the factors that influence absorptive capacity within organizations. However, the mechanism of how related factors affect absorptive capacity across interdependent organizations in project networks remains less explored. This paper extends a simulation model of project network learning to explore the absorptive capacity of project networks where periodic external innovations exist. This model is utilized in a series of simulation experiments to untangle the effects of varying types of innovation and degrees of relational instability in a project network. We establish a measure of project network absorptive capacity and develop an argument that relational instability moderates the project network's absorptive capacity for different types of innovation. These findings have significant implications for assessing and developing strategies to improve a project organizational network's capacity to absorb and, hence, profit from innovation. [ABSTRACT FROM AUTHOR]

Construction engineering is all about production, and producing something useful is the very reason for projects to exist. How then to explain why construction engineering has progressively fallen out of focus in construction project management education and research? For an answer, the development of the discipline of construction management since the 1950s must be understood, a development that yielded a non-production-oriented approach to project management, one that provides the currently accepted operating system for managing the work in projects. This paper first traces the history of the development of the traditional operating system and related commercial terms and organizational practices. It argues that traditional practices rest on an assumption that careful development of a project schedule, managing the critical path, and maximizing productivity within each activity will optimize project delivery in terms of cost and duration. Subsequently, an alternative operating system, developed and proposed by the Lean Construction community, is described. In contrast to the traditional approach, lean defers detailed planning until closer to the point of action, involves those who are to do the work in designing the production system and planning how to do it, aims to maximize project performance (not the pieces), and exploits breakdowns as opportunities for learning. The history of this development will be traced in broad strokes. [ABSTRACT FROM AUTHOR]

Earthmoving and construction equipment have evolved significantly during the past century. During the same time, our ability to study and understand equipment economics and productivity has also gained significant ground. This paper relates some of the recent academic research to industry practices. In doing so, it validates some parts of the research and makes new observations in three areas: repair costs, residual values, and total cost of ownership (TCO) and productivity. It also provides a few pointers for future research. [ABSTRACT FROM AUTHOR]

In a recent survey of clients and buyers of construction, the Construction Management Association of America (CMAA) found that over 50% of design efforts finish behind or significantly behind schedule. Furthermore, it found that 70% of clients have seen the quality of design documents decrease over the past 10 years with 97% of clients agreeing that designers should be held more accountable for the quality of the designs that are delivered. This paper presents the research results of applying a new approach to contracting design professionals that enforces accountability and minimizes risk. The new approach theorizes that the inefficiencies in the design industry are because of the selection and contract management system used by most clients. The first 39 design project test results are presented, along with the evolution of the design delivery model. Key findings include the threat of political risk to change, the inability of most design professionals to address specific project risk, and the lack of preplanning evident in most design projects. [ABSTRACT FROM AUTHOR]

In this research, variation is defined as the time difference between what was planned and what actually happened in terms of task starting times and duration. Variation in construction tasks is important as it can impact productivity performance. Construction projects consist of a large number of interdependent tasks. When the starting time and/or duration of one task varies, it can affect other downstream tasks and result in disruptions to the schedule and/or decreased productivity. The construction process is complex and involves numerous people with different levels of responsibility, which makes identifying the root causes of the variation difficult. A nationwide survey was administered to workers, foremen, and project managers to identify the most prevalent causes and magnitude of both starting time and task duration variation. Fifty individual causes of variation were divided into eight categories: prerequisite work, detailed design/working method, labor force, tools and equipment, material and components, work/job site conditions, management/supervision/information flow, and weather or external conditions. This research examined the similarities and differences in perceptions between craft workers, foremen, and project managers in terms of starting time and task duration variation. The top eight causes of starting time variation and top nine causes of task duration variation were identified. The research also quantitatively analyzed the underlying structure of the causes of variation using factor analysis. This was done by grouping the 50 individual causes into nine orthogonal factors that represent the underlying structure of the affecting causes. The findings will help construction project managers and field managers focus on the root causes of variation during planning in order to develop effective strategies to reduce variation and improve project productivity performance. [ABSTRACT FROM AUTHOR]

Although some new technologies promise to improve construction productivity, their ability to deliver is not always realized. Building on a great deal of prior research, a four-stage predictive model was developed and validated to estimate the potential for a technology to have a positive impact on construction productivity. The four stages examine the costs, feasibility, usage history, and technical impact of a technology. The predictive model combines results from historical analyses to formalize how selected technologies with improved construction productivity can be used as a predictor of how future technologies might do the same. Each of the stages of a predictive model was subdivided into a series of categories and questions, which were weighted by importance by using the analytic hierarchy process and historical analysis to generate a performance score for the analyzed technology. The predictive model was then validated by using 74 previous and existing construction technologies. Statistical analysis confirmed that average performance scores produced by the model were significantly different across the categories of successful, inconclusive, and unsuccessful in the actual implementation experience of technologies. [ABSTRACT FROM AUTHOR]

Many existing studies about construction schedule management focus on the planning phase of a project, particularly on schedule estimation based on the labor resources involved in the project. However, equipment resources, which are another crucial factor in the productivity of a construction project, have not been considered in existing research. Therefore, this study aimed to develop a schedule estimation model considering both labor and equipment resources. For the purpose of this study, core wall construction was selected because it is a very important construction activity in terms of schedule estimation for high-rise building construction. To develop a schedule estimation model for core wall construction, an in-depth case study was conducted. On the basis of the results of the case study, a simulation model was developed using the CYCLONE method. Finally, by using the results of the simulation, a schedule estimation model for core wall construction was developed by conducting multiple-regression analysis. By using the developed model, a project manager can easily, quickly, and accurately perform schedule estimation when there are problems that may cause construction schedule delays during the construction phase. [ABSTRACT FROM AUTHOR]

This paper presents a case study of a bridge constructed under adverse conditions in rural Florida. The major challenges facing the contractor were clearly identified through analysis. The bridge was constructed by an established, experienced bridge contractor that faced many daunting challenges in the construction of the bridge foundation, ranging from overdesign to the project manager managing his first construction project. However, the biggest challenge was unforeseen site conditions; namely, some of the most difficult clay imaginable through which to drive piles. These challenges forced the contractor into several tactical maneuvers. In sharing both the methods adapted by the contractor and the results of the adaptations, this paper quantifies for researchers and practitioners how a good contractor made sound, fundamental decisions to overcome severe challenges, improve productivity rates midproject, and eventually make the project a success. A seeming disaster early on, the project was eventually completed in less than the contract duration and at a sizable profit for the contractor. [ABSTRACT FROM AUTHOR]

Improvement of productivity in construction has been a major industry challenge, given its high impact on project results. It has received increased attention from construction researchers promoting different enhancement actions, since analyzing factors affecting labor productivity is an instrumental part in this process. This paper focuses on identifying and understanding the productivity factors affecting projects in a Chilean construction company on the basis of questionnaires administered to both direct workers and midlevel employees. Analysis of the questionnaire results helped to determine organizational and managerial weaknesses and facilitated comparison of the findings with previous productivity studies. The results proved to be useful in developing recommendations for productivity improvements. The main findings indicate that the critical areas affecting construction productivity were related to materials, tools, rework, equipment, truck availability, and the workers' motivational dynamics. These results are similar to those obtained in previous studies in the United States and in Chile. Salary expectations were found to be the main reason for turnover in the studied company, which was an aspect not mentioned in previous studies. Finally, additional analyses seem to show that some factors affecting productivity are common to construction projects across boundaries, therefore validating data aggregation and the possibility of learning from experiences in different locations and even separated in time of occurrence. [ABSTRACT FROM AUTHOR]

Frequent and regular prediction of productivity is needed to effectively manage construction operations in progress. This need is proven by significant deviations in productivity between estimated values and actual values, and the dynamic and stochastic changes in productivity over time. Five statistical methodologies that are appropriate for contemporaneous time series were cross validated in the present study. Validation was conducted by comparing the performance of forecasting models constructed using the methodologies. Performance was measured by evaluating the residual sum of squares and the correlation coefficients. As a result, univariate time series analysis was found to be the best-performing methodology. The univariate time series model is particularly beneficial in two respects. Using a single series of contemporaneous productivity data in numeric form, it reduces the effort expended in collecting and analyzing data, and improves the objectivity of analysis. [ABSTRACT FROM AUTHOR]

Productivity has a profound impact on projects that depend on time and cost of construction operations. In addition, time and cost estimates are derived from productivity. Thus, accurate prediction of productivity is essential to effectively plan and control construction operations. Predicting productivity of ongoing operations, however, is challenging. Due to dynamic and stochastic changes in productivity over time during construction, frequent and regular forecasting of short-term productivity is critical in managing ongoing operations. The present research investigated the characteristics of series of periodic productivity that should be taken into consideration to effectively predict short-term productivity continually and proactively. Given the identified characteristics, this study reviewed a few potential statistical methodologies that can make full use of contemporaneous time series data related to production for the purpose of predicting short-term productivity by using trend analysis. The methodologies were demonstrated in this paper using an example case, through which data processing and modeling procedure for modeling contemporaneous series data were explained. [ABSTRACT FROM AUTHOR]

Proving and quantifying lost productivity due to cumulative impacts of multiple changes are difficult tasks. This paper presents the most acceptable methods from case law and demonstrates their applications for analyzing the loss of productivity. These methods include earned value analysis, measured mile analysis, and combinations of these two. They are either well established or drawn from recent court and board decisions. A case study is used to illustrate and compare the use of these methods. These methods result in considerably different loss of productivity values though the actual amount (i.e., inefficiency in labor hours) is unique for a particular case and though these methods are often thought to be similar or even the same. How a measured mile analysis and its variants are employed affects the amount of lost productivity estimated. The variants can avoid some drawbacks of measured mile and earned value studies. Nevertheless, which method is more accurate and reliable is difficult to provide for a particular claim. Practitioners should choose between them based on the availability of project records and the nature of changes and cumulative impacts. Practitioners may also employ two or more methods to perform a “sensitivity analysis” of the chosen methods and persuade the other party and/or the jury that their estimate of lost productivity is sufficiently certain. [ABSTRACT FROM AUTHOR]

Developing and developed countries need to increase their investments in infrastructure to support economic growth, productivity, and the competitiveness of their economies to enhance the well being of their populations. Some of these investments, being long term, illiquid and considered public services, tend to be undertaken by the public sector. Nevertheless, in some sectors and at different points in history, there has been considerable participation by the private sector. For the purposes of enhancing these investments, all possible options of private and public participation must be considered and the needs are such that ideology and semantics should not get in the way. From the very extensive experience in developing countries, it has been learned that selecting the proper modalities can enhance the long term viability of the investments, can increase the number of bankable projects, attract investments and reduce backlash from failures. These lessons can be applied to developed countries as well. This paper presents a model for the selection of the most suitable service delivery modalities adapted to the prevailing local conditions of the country. [ABSTRACT FROM AUTHOR]

The global seaport sector made huge efforts in relation to port reform and technological development since the 1990s. This study attempts to systematically estimate the impacts of these efforts on world ports’ efficiency changes between 1991 and 2004. The Malmquist Total Factor Productivity Index can effectively measure efficiency changes and identify sources of efficiency gains and losses. Based on the decomposed Malmquist Productivity Index efficiency indices, this study creates a typology of ports regarding whether, and how, they have improved their efficiency over the last decade. The results suggest that: (1) while scale efficiency, mainly representing impacts of external economic environments on port performance, is still one of the important factors to shape port efficiency, it is neither determining nor predominant any longer; (2) the globalized competition in the container shipping and terminal markets enables potential strategies to be used that combine institutional restructuring and capital investment, as a partial solution to overcome the external limitations of ports, such as lack of hinterlands; and (3) an exclusive focus on aggressive investment in technological progress is a limited strategy, as other competitor ports can relatively easily replicate the process, and, consequently, it may negate any increase in long-term competitiveness. [ABSTRACT FROM AUTHOR]

Performance measurement is a helpful tool for taking corrective actions and controlling a project as far as this enables accurate time and cost forecasts during the first stages of the construction effort when the management team still has opportunities to make adjustments. This paper overcomes the dilemma of practicability and predictability of traditional estimates at completion based on early progress measurement by presenting the empirical results from the construction project of an industrial facility. The case may be a reference practice for assessing time and cost performance measurement of any building, whose layout can be reasonably partitioned into repeatable portions. In such circumstances, an effectively-managed traditional earned value method and appropriate metrics for computing performance provide project managers with accurate forecasts as useful tools for successful project management and control. [ABSTRACT FROM AUTHOR]

The crucial problem of construction debris is of increasing concern in Hong Kong. In the construction industry, the electrical and mechanical (E&M) installations in the infrastructure, for example, buildings, tunnels, or dams, are some of the major and usually complex components. Difficulty in coordinating the various trades affects productivity in general, and has a major impact on the quantity of construction debris. By identifying the sources of waste at each stage of E&M engineering work, some of the construction debris can be eliminated at the source during production. This paper investigates the critical production shortcomings in the E&M sector in Hong Kong. The study is based on a survey that includes a preliminary questionnaire survey, brainstorming exercises with a focus group, structured interviews with experienced frontline supervisors, and a second focus group exercise to test findings and proposed measures. The principal findings are that “poor coordination” and “design changes and/or errors” are major contributors to variations or change orders and rework, which in turn result in a high volume of construction debris. The results also indicate that construction debris can be minimized in the E&M sector of the construction industry, if the material wastes from incidental work are reduced and also controlled better in a new work process flow pattern through recommended construction project management improvements for reducing critical production shortcomings. [ABSTRACT FROM AUTHOR]

This paper describes a new integrated method of linear schedule analysis using singularity functions. These functions have previously been used for structural analysis and are newly applied to scheduling. Linear schedules combine information on time and amount of work for each activity. A general model is presented with which activities and their buffers can be mathematically described in detail. The algorithm of the new method forms the body of the paper, including the steps of setting up initial equations, calculating pairwise differences between them, differentiating these to obtain the location of any minima, and deriving the final equations. The algorithm consolidates the linear schedule under consideration of all constraints and, thus, automatically generates the minimum overall project duration. The model distinguishes time and amount buffers, which bears implications for the definition and derivation of the critical path. Future research work will address float and resource analysis using the new model. [ABSTRACT FROM AUTHOR]

The construction industry relies on skilled craft workers supplied through various training programs. Based on a nationwide survey of industry experts regarding craft training programs, this paper examines the current state and effectiveness of construction craft training via 93 respondents from a wide range of U.S. industrial and commercial construction firms and associated craft training centers. The study’s survey data allowed the writers to examine the major issues regarding craft training, such as the relative importance of basic core topics, training completion rates, the relation between trades’ engagement and training, and the barriers of advancing craft training in construction. The paper also uses the experts’ responses to estimate the benefits of craft training on productivity, turnover, absenteeism, safety, and rework. Various statistical methods are used to support the analysis. Problems are identified in craft training among the training programs examined and potential solutions for improving craft training effectiveness are suggested. [ABSTRACT FROM AUTHOR]

It has been advocated that information available from a performance measurement system (PMS) is an invaluable source of knowledge for contracting organizations. As such, it has been suggested that performance improvement can be achieved if contracting organizations can capitalize on the learning opportunities accorded from feedback derived from a PMS. Literature on learning also suggests that organizations display three types of learning: (1) single loop, double loop and Deutero. This paper reports a study that aims to (1) empirically test the positive effect derived performance feedback on performance; and (2) identify the extent to which the learning types have significant impact on performance improvement. Data on performance, performance feedback available, and responses were collected through a questionnaire survey. Pearson correlation and multiple moderated regression were used to accomplish research objectives (1) and (2), respectively, as mentioned. The findings suggested that there is a significant correlation between performance improvement and feedback from a PMS. It was found that all three forms of organizational learning can contribute to performance improvement and are not mutually exclusive. Nonetheless, double-loop learning practices that addresses the root causes of underperformance were found to be more versatile in facilitating improvement in efficiency and effectiveness. [ABSTRACT FROM AUTHOR]

This paper compares the relative productivity of construction industry sectors with significant off-site fabrication with more traditional on-site sectors. The off-site sectors, such as curtainwall, structural steel, and precast concrete fabrication, consistently show higher productivity growth than on-site sectors. Furthermore, the value-added content of the off-site sectors is increasing faster than that of the on-site sectors, indicating faster productivity growth. However, the off-site sectors are not traditionally considered as part of the construction industry by the U.S. Economic Census, but rather as manufacturing. Ignoring the off-site segments of construction has led to significant underestimation of construction productivity. [ABSTRACT FROM AUTHOR]

The condition and performance of bridges vary widely across North America. The large amount of expenditures on bridges needs significant efforts to optimize budget and resource allocation and to select the best rehabilitation or replacement method, which reduces project cost and duration. Simulation has been widely used in the construction area to optimize productivity and resource allocation. Current research optimizes resource combination for bridge deck rehabilitation projects using discrete event simulation. The Jacques Cartier Bridge redecking project is selected as a case study. Data related to productivity and duration of different activities were collected from the project. Probability distributions are fitted, which show the robustness of normal distribution to fit most variables. A simulation model is developed for this project in order to experiment with and perform sensitivity analysis. Based on the simulation results, an optimum resource combination of deck rehabilitation is obtained, which is [five teams, two saws, three old section trucks, and five new panel trucks] TSON 5235 with the unit (panel) cost of $747/h (direct cost only). The model developed is tested against real productivity where it shows reasonable results. The present research is relevant to both researchers and practitioners. It provides bridge redecking researchers with a real case study, a simulation model, and an approach to analyze projects. It also provides practitioners with an approach to optimize the usage of their resources considering direct project cost. [ABSTRACT FROM AUTHOR]

Operators of tower cranes enjoy a bird’s eye view of the site, which undeniably contributes to work safety and efficiency. Yet their work often involves blind lifts, as well as other viewing difficulties, that impede full utilization of the potential inherent in the operator’s location atop the crane. This paper reports on a tower-crane-mounted live video system that offers a solution for such difficulties, and consequently, enhances safety, improves productivity, and brings about direct and indirect cost savings. The development and implementation of the vision system are described as a successful academia–industry research and development joint effort. Work studies of numerous craning cycles resulted in considerable time savings, depending on the nature of the lift, lighting conditions, and viewing obstructions. In addition, a detailed list of benefits drawn on the basis of feedback received from the field is presented. The paper is aimed, first and foremost, at project managers as well as construction equipment and safety practitioners, who daily experience those situations that have prompted the development of the system. Researchers may benefit mainly from the lessons learned with respect to the role of academia–industry cooperation in the introduction of innovative systems in construction. [ABSTRACT FROM AUTHOR]

A construction process reengineering framework and its corresponding methodologies have been developed by integrating lean principles and computer simulation techniques. Instead of classifying activities into value-adding and non-value-adding activities, or into conversion and flow activities as is common in lean production practices, this framework classifies activities into main and supportive activities and/or into normal and interactive activities. This classification makes it more effective in modeling the construction workflow and reengineering the construction process. It also avoids the confusion of the classification of activities into value-adding and non-value-adding activities encountered in the construction industry. In addition, computer simulation techniques are incorporated into the framework to virtually simulate and assess the efficiency and effectiveness of the reengineered construction process that is achieved based on lean principles. Simulation makes it easier to quantify and assess the effectiveness and efficiency of the reengineered construction process. [ABSTRACT FROM AUTHOR]