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doi: 10.1080/01446199300000060pmid: N/A
Japan's big five general contractors — Kajima, Obayahi, Taisei, Takenaka and Shimizu — have developed efficient production systems for their construction site work. Earlier studies show that this has been achieved by applying a very standardized approach. Yet the Japanese building industry undertakes extensive research and development, the application of which could reasonably be expected to disrupt the efficient construction-site production systems. This paper describes a study undertaken in mid-1991 that began by exploring the relationship between the research institutes and the mainstream project work of the big five. This led to a review of established theories about the way that innovation takes place which in turn directed the study towards the interaction between the big five and their environments. Two major changes in these environments are currently under way. The first is growing demands by the big five's customers for higher standards and more fashionable design. The second is a serious labour shortage in the Japanese building industry. The big five have reacted in different ways to these two major environmental changes. This discovery finally led the study into a concern with the models that managers use in understanding their work. The paper suggest that a new model, based on using the human nervous system as a metaphor, is needed in order to understand the behaviour of the big five. It is also proposed that such a model will help in designing appropriate organizations for the big five as they face and seek to influence the rapid changes now resulting from the ambitions of Japan's increasingly affluent society.
doi: 10.1080/01446199300000061pmid: N/A
The paper presents a systematic methodology for forecasting the demand for construction labour in various skills, within a national economy. Major factors, which determine the future needs for dwelling units and for other types of construction, are discussed in detail, while the strengths and weaknesses of different forecasting approaches are highlighted. Possible sources, available in most countries, for statistical information, as well as the International Classification of Occupations and Economic Branches, are identified and evaluated. The methodology is general and may be applicable to any country. It is illustrated by an example of such a forecast for the next decade, performed by the authors in Israel, in the years 1988 and 1989. The various demand and supply parameters, which formed a basis for this forecast, significantly changed with the unexpected surge of immigration from the Soviet Union in 1990. The effects of this change are discussed separately in the paper.
John O'Brien, Mark; Paris Pantouvakis, John
doi: 10.1080/01446199300000062pmid: N/A
Estimators display a diversity of approaches to their task of predicting the cost of a construction project. To design and build individualized, computer-aided estimating software products to reflect this diversity is however expensive. This paper describes a new method of designing and building such products which is quick, easy and hence inexpensive. The method relies upon embedding a core estimating product into a set of software tools which can be used to reshape and enhance the core functionality. The tools have been designed to minimize the requisite technical knowledge of the user, principally through the use of declarative features. The individualistic nature of estimating is therefore reflected in this new method of developing estimating products. These resultant products are therefore more acceptable to practising estimators.
doi: 10.1080/01446199300000063pmid: N/A
A number of procedures have been formulated in recent years for evaluating engineering, procurement and construction projects based on an established set of objectives. These procedures, however, have generally considered either multi-objectives without the risk associated with each objective or a single objective with some form of risk assessment. Decision aid methodologies that permit the consideration of both multi-objectives and risk have generally been associated with complex mathematics and high computational effort. The purpose of this paper is to present a simple, yet comprehensive methodology for the selection of a project under risk, avoiding time consuming analyses. The method considers multi-objective decision criteria and takes into account the uncertainties associated with each individual objective. The method is based on multi-attribute utility theory for modelling the selection criteria and treats uncertainty in a similar way to that used in Program Evaluation and Review Technique (PERT). A numerical example is presented to demonstrate the application of the present method.
doi: 10.1080/01446199300000064pmid: N/A
Reasons for the occurrence of the non-uniformity of production processes in construction and an outline of a formal approach that makes use of the theory of stochastic processes and statistics have been given. Attention has been drawn to the necessary and satisfactory conditions for balancing these processes. The distinction between the distribution of work time and the distribution of production volume (characterized by opposite skewness) has been introduced. A few cases of diminishing the non-uniformity have been given; the existence of mutual relations between the intensity of processes, concentration (superposition) of the processes and their non-uniformity have been used for that purpose. Examples of a superposition of processes (as a case of concentration of production) have been taken from the production and deliveries of concrete mixture. Attention has been drawn to savings resulting from such actions. These savings often require only simple technical or organizational operations.
doi: 10.1080/01446199300000065pmid: N/A
The paper compares two domestic cooling systems, namely the air-conditioner and the direct evaporative (desert) cooler, using a life cycle costing approach. Both systems are capable of providing a certain degree of cooling relief during the hot and dry conditions typical for the summer in arid regions, such as the city of Eilath, Israel. Each, however, utilizes a different thermodynamic principle, thus possessing different features that affect the expenses involved in cooling the residential apartment. The criterion for the economic evaluation is the system's Annual Equivalent Cost. This parameter represents a common denominator of annual cost involving purchase, installation, operation, and maintenance of each system. The evaluation of operating costs considers the hourly variations in the cooling load as a function of the changing outdoor conditions, the thermal properties of the enclosure and the cooling pattern of the building. For the air-conditioner, the analysis accounts for the relationship between both outdoor and indoor thermal conditions and its electric energy consumption. For the direct evaporative cooler, the operating costs originate from electric energy consumed and from the cost of the water evaporated and drained to carry on the evaporative cooling process. The comparison is performed in middle-class apartments and is limited to comfort level achievable by the desert cooler. The economic model is simple yet detailed, and it has been derived in a manner that most conveniently accommodates small energy consuming systems in buildings. Such systems typically consist of one principal part — the mechanical system — and several auxiliary sub-systems (piping, wiring, etc.), the separate operating and maintenance costs of which are hard to determine. The analysis shows that for the prevalent conditions in Eilath, the desert cooler is significantly more economical to own and operate than the conventional air-conditioner. Analysis demonstrates that this superiority remains for a range of realistic changes in both economic and thermodynamic parameters. In spite of a slightly higher initial cost, the desert cooler proves to be more economical, mainly due to its significantly lower operating cost.
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