SERC—A Model for Estimating Construction Inputs

One of the main problems in the process of design and management of construction projects is obtaining accurate information for preliminary estimates. This information is crucial for the development of integrated systems for construction management because of the relationship between construction input data and subjects such as estimating, cost control, scheduling, resource management, etc. Existing methods for estimating input that originated in industrial engineering are inadequate for the unique conditions of the construction industry. The model described in this paper applies statistical analysis of data from past projects, and enables the user to estimate the data needed for the construction of a new project. The model is based on the following components: Project items and their quantities; inputs needed to produce those items; and factors that affect inputs of a specific project. The model equation was calculated using multiple regression techniques. The paper concludes with a case study of a construction input configuration for a concrete structure.     

Automation of data acquisition and of experiment control: application to the study of sleep-wake cycles and behavioral paradigms

The low cost of microcomputers allows them to be dedicated full time to data acquisition and analysis of experimental paradigms. The usual interfaces required for such interaction with the experiment are briefly explained, namely, analog-to-digital converters, input-output control lines and real time clocks. Some basic concepts on the use of microcomputers for the automation of data acquisition and control are summarized, including the characterization of waveshapes, the structure of data storage and on-line data reduction. Off-line, the matrices generated by the data acquisition program become the input for ad-hoc processing programs. Precision, flexibility and fluidity of analysis are outstanding advantages of computer controlled setups. A system for automation of sleep studies and a system for automation of scheduled-controlled behavior are presented as working examples.     

Programmatic Cost Risk Analysis for Highway Megaprojects

Highway megaprojects (construction projects over $100 million) are fraught with uncertainty. These projects have historically experienced increases in project costs from the time that a project is first proposed or programmed until the time that they are completed. Persistent cost underestimation reflects poorly on the industry in general but more specifically on engineers. Traditional methods take a deterministic, conservative approach to project cost estimating and then add a contingency factor that varies depending on the stage of project definition, experience, and other factors. This approach falls short, and no industry standard stochastic estimating practice is currently available. This paper presents a methodology developed by the Washington State Department of Transportation (WSDOT) for its Cost Estimating Validation Process. Nine case studies, with a mean cumulative value of over $22 billion, are presented and analyzed. Programmatic risks are summarized as economic, environmental, third party, right-of-way, program management, geotechnical, design process, construction, and other minor risks. WSDOT is successfully using the range cost output from this procedure to convey project costs to management and the public.     

Simplified Spreadsheet Solutions.?I: Subcontractor Information System

This paper presents a subcontractor information system (SIS) to support the estimating and project control functions of subcontractors and small∕medium-size contractors. For the proposed SIS to be simple and practical, it was developed in a spreadsheet program designed to maintain information related to resources and projects and to generate important business reports. Resource data are stored in six worksheets for labor, equipment, crews, material, subcontractors, and alternative methods of construction for various tasks. In addition, a separate worksheet is designed for each project to be used for estimating and control purposes. The latter worksheet allows the user to specify the work breakdown structure and optional methods for construction. As such, it represents a transparent estimating model that allows for quick what-if analysis regarding time and cost. In addition, the reporting worksheet provides information related to time, cost, and resource use at the individual and the multiproject levels. In a companion paper, the use of the SIS as basis for overall schedule optimization is described.     

Multiple Simulation Analysis for Probabilistic Cost and Schedule Integration

One of the major goals of the construction industry today is the quantification and minimization of the risk associated with construction engineering performance. When specifically considering the planning of construction projects, one way to control risk is through the development of reliable project cost estimates and schedules. Two techniques available for achieving this goal are range estimating and probabilistic scheduling. This paper looks at the integration of these techniques as a means of further controlling the risk inherent in the undertaking of construction projects. Least-squares linear regression is first considered as a means of relating the data obtained from the application of these techniques. However, because of various limitations, the application of linear regression was not considered the most appropriate means of relating the results of range estimating and probabilistic scheduling. Integration of these techniques was, therefore, achieved through the development of a new procedure called the multiple simulation analysis technique. This new procedure combines the results of range estimating and probabilistic scheduling in order to quantify the relationship existing between them. Having the ability to accurately quantify this relationship enables the selection of high percentile level values for the project cost estimate and schedule simultaneously.     

标准成本管理制度的实际运用

标准成本管理制度是一种成本控制系统,实施标准成本核算体系及管理体系,可以起到降本增效的作用。而实施标准成本核算体系及管理体系必须建立完善的标准成本管理制度,充分发挥财务人员的积极能动作用。     

Probabilistic Optimal-Cost Scheduling

During the planning and execution of construction projects, it often becomes necessary to shorten the duration of the project. A widely used technique for reducing the duration of a project is commonly referred to as least-cost scheduling. This procedure is based on deterministically arriving at the shortest project duration for the minimum cost possible. There is, however, one major problem with the typical application of this technique. It does not address the variability inherent in the duration and cost of the project activities. Thus, the resulting compressed schedule value cannot be applied with any stated level of statistical confidence. This paper presents a new procedure that addresses some of the major shortcomings of least-cost scheduling. It does so by accounting for the variability inherent in the duration and cost of the scheduled activities by simultaneously applying range estimating and probabilistic scheduling to the historical data. The resulting data set is then analyzed to provide a compressed schedule duration and cost estimate that have a higher overall confidence of being achieved.     

作业成本法在物流管理中的应用实践

通过对物流作业时间、空间、作业量和价值数据采集,确定物流作业成本的组成,对物流作业进行成本核算。将间接成本和辅佐资源更准确地分配到物流作业中,对物流作业进行成本独立核算,实现物流作业管理。根据成本管理原则对物流作业进行管理,利用价值工程理论使企业物流体系效益最大。运用成本的统一尺度衡量物流作业,反映物流活动的价值,优化物流系统的资源配置,实现业务流程再造,从作业链管理逐步向价值链管理方向发展。     

Linking Time-Lapse Digital Photography and Dynamic Scheduling of Construction Operations

A dynamic scheduling system that links digital movies of construction activities, a CPM schedule, and progress control of construction has been developed. A time-lapse technique has been used in such a way that months of construction performance can be watched in minutes. A method to produce a digital movie has been developed allowing thousands of pictures to be stored in, and managed by, microcomputers under a Windows environment. A recording system has been introduced enabling the user to specify the day-by-day progress achieved in activities undertaken, allowing the program to link the playback movie with the progress observed on the construction field. A CPM engine has been developed to produce a Gantt chart. A procedure to build a histogram of expected cumulative percentage of progress is presented. An animation engine has been built in order to generate new bars reflecting the progress reported on the bar chart and the histogram, working in synchrony with the playback movie.     

Optimum Design and Management of Pressurized Branched Irrigation Networks

The scarcity of water resources is the driving force behind modernizing irrigation systems in order to guarantee equal rights to all beneficiaries and to save water. Traditional distribution systems have the common shortcoming that water must be distributed through some rotational criteria. This type of distribution is necessary to spread the benefits of scarce resources. Irrigation systems based on on-demand delivery scheduling offer flexibility to farmers and greater potential profit than other types of irrigation schedules. However, in this type of irrigation system, the network design has to be adequate for delivering the demand during the peak period whilst satisfying minimum pressure constraints along with minimum and maximum velocity constraints at the farm delivery points (hydrants) and in the pipes, respectively. In this paper, optimum design and management of pressurized irrigation systems are considered to be based on rotation and on-demand delivery scheduling using a genetic algorithm. Comparison is made between the two scheduling techniques by application to two real irrigation systems. Performance criteria are formulated for the optimum design of a new irrigation system and better management of an existing irrigation system. The design and management problems are highly constrained optimization problems. Special operators are developed for handling the large number of constraints in the representation and fitness evaluation stages of the genetic algorithm. The performance of the developed genetic algorithm is assessed in comparison to traditional optimization techniques. It is shown that the methodology developed performs better than the linear programming method and that solutions generated by the modified genetic algorithm show an improvement in capital cost. The method is also shown to perform better in satisfying the constraints. Comparison between on-demand and rotation delivery scheduling shows that a greater than 50% saving can be achieved in total cost at the cost of reducing flexibility in the irrigation time. Finally, it is shown that minimizing standard deviation of flow in pipes does not result in the best distribution, and therefore minimum cost, neither for systems with uniform flows or those with large variations in discharge at hydrants.     

System of Multiple ANNs for Online Planning of Numerous Building Improvements

The aging infrastructure in North America and worldwide mandates large investments in repair and improvement (R&I) activities. For organizations that own many assets, managing a large number of R&I activities is not a simple task and requires accurate estimating and scheduling so that proper budgeting and resource allocation decisions can be made. To support these decisions, this paper introduces a Web-based system that estimates the cost and duration of a user-requested R&I activity and provides alternative schedules based on resource availability. For estimating, the Web-based system hosts 32 artificial neural networks (ANNs), trained on actual historical data, for 32 common R&I activities in building projects. Each ANN incorporates a sensitivity analysis to consider the uncertainty in the input parameters on the estimate, and is linked to a central scheduling algorithm for resource allocation based on a first-come first-serve basis. The automated system helps practitioners in planning numerous R&I requests with least time, cost, and paper work. Details on system development are provided in this paper along with perceived benefits and the opinion of users on its performance.     

矿山企业成本因素及控制探析

成本管理是企业管理的重要组成部分,也是衡量企业生产经营管理能力、综合竞争发展实力的重点评价指标,是贯穿企业整个生命周期的持续性话题。矿山企业成本管理与普通企业成本管理既有相似性,又有其独特性,受到更多的成本因素的影响。通过对成本管理理念进行解析,对矿山企业成本因素进行辨识,对矿山企业成本控制措施进行了初步探析。     

Improving Cost Estimates of Construction Projects Using Phased Cost Factors

Central to cost-based competition is the capability to accurately predict the cost of delivering a project. Most literature on cost estimation focuses on specific estimation methods as generic techniques and little attention has been paid to the unique requirements at each project stage. This note attempts to identify the critical factors for effective estimation at various stages of typical construction projects. Drawing from organization control theory and cost estimating literature, this note develops a theoretical framework that identifies the critical factors for effective cost estimation during each project phase of a conventional construction project. The underlying logic is that as a cost estimating effort progresses, both task programmability and output measurability improve. As a result, control effort will shift from input-oriented control to a combination of output and behavior control.     

Cost Control in Consulting Engineering Firms

Consulting engineering companies need an adequate cost control system to improve their profitability and productivity. Cost control enables the firm to make decisions if the measurements do not comply with the initial targets. This paper introduces a new theoretical approach to cost control and its implementation procedure. Technical (or productive) personnel costs are considered as indirect costs. A general principle stated is the total absorption of overhead costs by billable time of technical personnel. The proposed methodology establishes time as the key element of control in a professional services company. It considers production of consulting engineering firms as a function of time; therefore the productivity of the personnel can be controlled.     

Data Integration of Pavement Markings: A Case in Transportation Asset Management

Effective transportation asset management requires the implementation of tools such as software, hardware, databases, and data collection systems. Pavement markings make up one component in transportation asset management, which are complex networks that require large databases. Typically these databases are maintained in different areas within an agency and are most often incompatible. Combining new and old tools, this paper addresses the need for better data integration and utilization while incorporating current information technologies. Specifically, this paper presents integrated transportation asset management system for estimating the current and future condition of pavement markings. The paper describes the data structure, in the form of a physical model, integrating a pavement marking relational data schema with existing information technology systems. Software was found to be useful in developing the data schema. The software produced an extensible markup language file that is compatible with a variety of existing database structures such as Oracle, SQL, and MS Access. Additionally, the system included an algorithm, which implements the data structure and predictive models to estimate the condition of the asset at any point in time or space on the highway system. Using either measured data or predicted data the system gives managers an opportunity to decide on the best possible condition state of the asset and perform queries or optimizations. Ultimately, managers can develop cost effective strategies for pavement marking asset management.     

对现代企业制度下成本管理的几点看法

本文从成本管理对象、管理内容、控制体系3个方面提出了现代企业制度下,成本管理观念的更新与相适应的成本意识。     

Software for Planning and Cost Control in Directional Drilling Projects

As the complexity and size of the projects undertaken by horizontal directional drilling (HDD) contractors rapidly increase, there is a growing need for the development of dedicated software designed to meet the industry’s special needs and requirements. This paper presents the results of a survey of the HDD industry’s software needs as well as a summary of commercially available software specifically designed for this industry. In addition, the development of two computerized applications tailored for the HDD industry are described. The first of these applications is an integrated data management system that combines asset management, cost control, estimating, and project tracking capabilities, enabling decision makers to closely monitor field performance in terms of expenditure and productivity. The second application is a simulation model developed for optimizing the utilization of drilling rigs and hydro-vacuum trucks on large-scale urban projects. Both applications are designed to improve the planning, estimating, and productivity of directional drilling projects, ultimately reducing the cost of expanding underground infrastructure networks.     

Games People Play with Cost Control in Australia

A study of a selected group of building and engineering construction contractors in the Australian construction industry was performed in order to determine the actual site cost control procedures and techniques being practiced. The study was conducted through a detailed questionnaire completed by the researcher during the course of interview sessions with the site managers of the 18 construction projects in the sample. The main trends disclosed from the questionnaire allowed a model of actual site cost control procedures to be flowcharted. This system was then subjected to a comparative analysis with an idealized site cost control system developed in a previous study. Cost control functions that are discussed in this paper include, among others, the method of work breakdown for site use in cost control, performance data feedback techniques and uses, yardsticks for cost control, and management action at the site. The study concludes with a set of general recommendations aimed to bring current site cost control practices more in line with the available body of knowledge.     

INES—An Interactive Estimating System

A possible effective application of computers in construction is to use them for cost estimating. Despite their wide acceptance for cost accounting and other bookkeeping tasks, their use in estimating has lagged considerably. The emergence of powerful and low cost microcomputer systems has made it feasible for a broad range of contractors to own their own system. As a result, it is now very common for even the smallest contractors to own a system whose primary function is bookkeeping. Once bookkeeping tasks are automated, however, a natural progression is to also use them for cost estimating. It has therefore become necessary to develop an estimating system which takes advantage of the great potential of the microcomputer. This paper proposes and describes one such system.