Papers by Keyword: Cost Estimation

Abstract: One of the owner’s common problem before executing construction projects is the complexity in estimating the project cost in an early stage. Inaccurate cost estimation will force the owner to make further arrangement to the project budget. This study aims to develop an initial cost estimation model for superstructures of Precast I-girder Bridge. Cost estimation model was developed based on thirteen data of detail engineering design of I-girder bridge in Daerah Istimewa Yogyakarta (DIY). Factors influencing the cost of the superstructures of the I-girder bridge were identified. Bridge span and width, the size of the sidewalk, and railing’s type are considered as variables affecting the cost of superstructures. These variables are then arranged into two different analysis Multiple Linear Regression (MLR) analysis and Artificial Neural Network (ANN), in order to obtain the best estimation model. The results of the analysis showed that bridge span and width were the significant factors influencing cost. The correlation value of bridge span is 89.0%, bridge width is 74.2%, the size of the sidewalk is 66.1%, and railing’s type is 46.1% as identified factors that affect the cost of the superstructure. A comparative model of two approaches shows that the ANN has better accuracy than that of MLR, although the difference was not significant.

Abstract: Every engine needs a cooling system in order to maintain the performance of engine. In this study the cooling system is applied in naval ship with the exchange of freshwater and seawater. Since the seawater contains biological fouling, then it is scaled in the heat exchanger so that the performance of heat exchanger is decreasing from time to time. This makes the heat transfer rate in cooler is less efficient so that to maintain the BHP of the engine it needs to consume more fuel. The result shows that the effect could incur a loss of about USD 463,852.8/month. This condition makes the importance of cooling system maintenance in order to keep the temperature of the naval ship engine and to minimize the additional fuel cost. For cooling system itself, to keep the cooler in a good condition, it needs to clean the cooler for every 720 hours, or once a month.

Abstract: The accuracy of software cost estimation is essential for software development management. By introducing and analyzing the estimation methods of software cost systematically, the paper discussed the necessary of considering the software maintenance stage and estimating the software cost by separating the procedure of software development into several small stages. Then a staged software cost estimation method based on COCOMO model was proposed. The use of the new software cost estimation method proposed by this paper not only contributes to the cost control of software project, but also effectively avoids the bias problem due to using by single cost estimation method so that the accuracy of cost estimation could be improved.

Abstract: The cost estimation of mold design is a hard issue because of the complexity and variety of the products. We assume that the cost is largely decided by the time for design since labor salaries are increasingly important nowadays. In this paper, we propose a platform to count all the time consumed in all the design details, from which several statistics and analysis reports are made. Based on the data, the managers can acknowledge all the processes details in the design groups. Moreover, bottlenecks in design can be prevised and corresponding measures can be taken in advance. The existing data can also be borrowed for the later quotation for the similar designs. Certain companies have deployed our system and verify that it greatly help the cost estimation and control.

Abstract: A cost estimation method is required to estimate the life cycle cost of a product family at the early stage of product development in order to evaluate the product family design. There are difficulties with existing cost estimation techniques in estimating the life cycle cost for a product family at the early stage of product development. This paper proposes a framework that combines a knowledge based system and an activity based costing techniques in estimating the life cycle cost of a product family at the early stage of product development. The inputs of the framework are the product family structure and its sub function. The output of the framework is the life cycle cost of a product family that consists of all costs at each product family level and the costs of each product life cycle stage. The proposed framework provides a life cycle cost estimation tool for a product family at the early stage of product development using high level information as its input. The framework makes it possible to estimate the life cycle cost of various product family that use any types of product structure. It provides detailed information related to the activity and resource costs of both parts and products that can assist the designer in analyzing the cost of the product family design. In addition, it can reduce the required amount of information and time to construct the cost estimation system.

Abstract: It has conducted a study on the cost calculation of spray component mould manufacturing process. In general, it is the present state that calculating machining time and cost for a unit process in mould manufacturing process depends on past experiences. In other words, it does not go beyond the level of computing and management by estimation based on the data conducted in the past. Accordingly, in the development of mould and new products tried for the first time, the cost calculation is not reasonable and thus a lot of time is needed. That is to say, not being able to actively and reasonably respond to the needs of the market that are changing every moment, the loss of management and money due to losing opportunities is frequently taking place. In this context, It have developed and applied a system that can reasonably calculate the cost by taking account of machining time calculation theory, machine, tool, material and working environment. As a result, calculating the time needed for a unit process in mould manufacturing process is possible, and it is possible to classify major processes and suggest alternatives in management. The system developed in this study used Visual Basic Language and SQL Database under Windows environment.

Abstract: In order to improve agricultural machinery product value in conceptual design scheme evaluation, a novel approach was put forward to evaluate conceptual design schemes in the view of value engineering. Realization of the method was divided into cost estimation and function evaluation. In cost estimation, weighted mahalanobis distance between historical data and estimating product schemes were calculated to express their similarity, their cost attributes were described by different membership functions, exponential smoothing method was selected to get estimation solution; in function evaluation, evaluation assignment was chosen to determine function coefficients of different schemes, by using improved AHP to modify judgment matrix. An example of sugarcane harvester is given to illustrate the validity and feasibility of proposed method.

Abstract: Power system related to the people's livelihood is an important lifeline and its rapid post-earthquake rehabilitation and reconstruction is particularly important. Considering the importance of power system, cost estimation method of post-earthquake rehabilitation of power system is proposed. Based on the direct economic losses of power system, post-earthquake rehabilitation cost is given by index of the post-earthquake adjustment factor which is put forward according to post-earthquake rehabilitation cost and direct economic losses of power system in “5.12” Wenchuan earthquake. Cost estimation method of post-earthquake rehabilitation of power system could provide good suggestions for post-earthquake rehabilitation work.

Abstract: The cost estimation of the product life cycle was researched. On the one side, the life cycle cost present value for manufacturer was estimated, including mainly of target cost, service cost and fault compensation. And a life cycle cost estimation model for manufacturer, which combines target cost and proportion cost estimated, was proposed. On the other side, the life cycle cost present value for user was estimated, including mainly of purchase, installation, commissioning costs in beginning and labor, maintenance, depreciation, maintenance costs in operations. And another life cycle cost estimation model for user, which combines process cost and proportion cost estimated, was proposed.

Abstract: At present, China's construction cost management lags far behind foreign countries, especially in the study on structural and material characteristics of construction. Based on Radial basis function neural network nonlinear model, the paper selected ordinary commercial civil engineering data of concrete building construction in the 2003-2007 years as samples, chose structural and material characteristics as cost indicators and estimated the cost prices. The results show that the method meets the requirements in the precision. Compared with other methods, it has the advantage of speed and generalization ability. The method provides project managers a better basis for decision making.