• Asia pacific journal of information systems
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• 제8권3호
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• pp.101-118
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• 1998

The purpose of this study is to construct a value-oriented sizing and cost estimation model for system integration projects. In particular, this study is to build a system architecture design and integration cost model, and a network design and implementation cost model. Unlike software development projects, system integration projects include knowledge-intensive professional services on system architecture and network design areas. Because of these work's high invisibility, the cost of these services is hard to estimate and measure. Therefore, we need to develop value-oriented cost models. This study presents 6 value-oriented cost models, and tests statistical significance of these models with real system integration project data. The results show that cost factors on these models are valid, and models are statistically significant. Future work is needed to integrate various cost models and apply the whole model to field projects to increase model's prediction accuracy.

• Journal of Construction Engineering and Project Management
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• 제4권1호
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• pp.15-28
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• 2014

Completing road construction projects within the budget and time has been a problem for the Tanzania National Roads Agency (TANROADS); and the major problem highlighted in almost all projects being inadequate design. However, the extent to which inadequate design contributes to both time and cost overruns and its causes remained under-studied. The objective of this study is therefore to determine the extent of the effect of inadequate design, its causes and remedial measures. The methodology used in this study includes reviewing recent projects completion reports, holding roundtable discussions with consultants and TANROADS officials and analyzing the information. Cost and time overruns for the reviewed projects averaged 44% and 26% respectively. Similarly, the extents to which inadequate design contributes to cost and time overruns were on average found to be 61% and 85% respectively. The overruns are predominantly related to problems that occurred during the design process. To alleviate the problem, TANROADS is advised to improve the management of design projects, enhance the process of reviewing design reports, improve the design process including introducing Road Safety Audit and geometric design manuals, and increase staff to match the work-load.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1923-1931
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• 2004

Manufacturing of complex surface plates in stern and stem is a major factor in cost of a preliminary ship design by computing process. If these hull plate parts are effectively classified, it helps to compute the processing cost and find the way to cut-down the processing cost. This paper presents a new method to classify surface plates effectively in the preliminary ship design using neural network. A neural-network-based ship hull plate classification program was developed and tested for the automatic classification of ship design. The input variables are regarded as Gaussian curvature distributions on the plate. Various applicable rules of network topology are applied in the ship design. In automation of hull plate classification, two different numbers of input variables are used. By observing the results of the proposed method, the effectiveness of the proposed method is discussed. As a result, high prediction rate was achieved in the ship design. Accordingly, to the initial design stage, the ship hull plate classification program can be used to predict the ship production cost. And the proposed method will contribute to reduce the production cost of ship.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.942-949
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• 2014

We studied about the rotor design change using a Ferrite ring magnet to reduce material cost in the condition of the same stator core design. However, this design direction has many weak points such as the decrease of BEMF, the low maximum output, the irreversible demagnetization characteristics of a permanent magnet and so on. In order to mitigate such disadvantages, an optimization design of the BLDC motor has been developed by changing each design parameter and by improving the electromagnetic structure. In the proposed water pump SPM BLDC motor using Ferrite magnet, the outer and inner diameter of stator is fixed to the value of the conventional IPM BLDC motor using Nd-Fe-B magnet. The design specification requirements should be satisfied with the same output power and efficiency characteristics in the same dimension. As a result of this study, the design comparison results considering driving performances and material cost are represented. Through the actual experiment with the prototype of the designed motor, the simulations results are verified.

• 상하수도학회지
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• 제27권4호
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• pp.413-428
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• 2013

In this study, Ant Colony Algorithm(ACO) was used for optimal model. ACO which are metaheuristic algorithm for combinatorial optimization problem are inspired by the fact that ants are able to find the shortest route between their nest and food source. For applying the model to water distribution systems, pipes, tanks(reservoirs), pump construction and pump operation cost were considered as object function and pressure at each node and reservoir level were considered as constraints. Modified model from Ostfeld and Tubaltzev(2008) was verified by applying 2-Looped, Hanoi and Ostfeld's networks. And sensitivity analysis about ant number, number of ants in a best group and pheromone decrease rate was accomplished. After the verification, it was applied to real water network from S water treatment plant. As a result of the analysis, in the Two-looped network, the best design cost was found to $419,000 and in the Hanoi network, the best design cost was calculated to $6,164,384, and in the Ostfeld's network, the best design cost was found to $3,525,096. These are almost equal or better result compared with previous researches. Last, the cost of optimal design for real network, was found for 66 billion dollar that is 8.8 % lower than before. In addition, optimal diameter for aged pipes was found in this study and the 5 of 8 aged pipes were changed the diameter. Through this result, pipe construction cost reduction was found to 11 percent lower than before. And to conclusion, The least cost design model on water distribution system was developed and verified successfully in this study and it will be very useful not only optimal pipe change plan but optimization plan for whole water distribution system.

• 한국CDE학회논문집
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• 제15권4호
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• pp.261-270
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• 2010

These days, architectural projects are becoming larger and more complex. And lots of information occurs through each phases and areas. For these reason, it is emphasized that collaboration with other parts. Therefore we need more effective architectural design process. However, it is difficult to collaborate in early stage with existing design process and it causes unnecessary spending of time and cost because of 2D-based working system. For solving these problem, we should introduce BIM-based Integrated Design Process which makes it possible to collaborate with other parts from early stage. Now the AEC industry in Korea has been trying to introduce BIM, and promoting variety of related business. However, for actual application of this system, it is unfortunately necessary to change various system throughout the construction industry. And this will cause lots of effort and expense. It is essential that scientific analysis and evaluation of efficiency and validity about this investment, because estimation of the investment and accompanying effects will provide reasonable standard of judgment for investment decision. Thus, this research conducted Cost-Benefit Analysis about BIM-based Integrated Design Process compared to existing design process. It is expected that this paper can be used for preliminary data in the future BIM market.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.719-726
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• 2005

The optimal design was performed for the bridge superstructure composed of steel box girders and concrete deck considering life cycle cost. The service life of the superstructure was estimated, after load carry capacity curves for steel girder and concrete deck were derived on the basis of condition grade curves and maintenance histories. The object function was determined as life cycle cost, including initial cost, total maintenance cost, disposal cost and user cost, for a period of the estimated service life. The optimal design of the superstructure was performed for the various service lifes. The annual costs were used to compare calculated results and to get the most economical design. Also this paper presents reasonable idea for the use of user cost with uncertainty.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.128-136
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• 2001

This paper presents an optimum deck and girder system design for minimizing the life-cycle cost (LU) of steel box girder bridges. The problem of optimum LCC design of steel box girder bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost, expected retrofit costs for strength, deflection, and crack. To demonstrate the effect of LCC optimum design of steel box girder bridges, the LCC optimum design is compared with conventional design method for steel box girder bridges design. From the numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on LCC will lead to more rational, economical and safer design.

• 한국강구조학회 논문집
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• 제13권4호
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• pp.337-349
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• 2001

교량은 계속적으로 변하는 하중 환경에 의해서 다른 구조물에 비해 비교적 빨리 노후화 되기 때문에 초기비용 이외에도 교량의 유지관리, 교통의 원활한 소통 또는 적체 등에 따른 비용, 교량의 손상에 따른 보수보강 및 교량의 해체 재건설 등 추가적인 비용의 영향이 크므로 공용간 생애주기 비용(LCC)을 설계단계에서부터 체계적이고 합리적으로 고려되어야 한다. 이에 본 연구에서는 강상판교의 설계에 있어서 주형의 휨 전단, 사용성, 피로에 대한 보강기대비용 등을 포함하는 LCC에 근거한 비용함수모형을 이용하여 이를 최적설계에 적용하고 기존의 설계방법과 비교 분석하였다. 적용예제의 결과에 나타난 바와 같이 LCC를 고려한 강상판 교량의 최적설계는 더욱 합리적이고, 경제적이며, 안전한 설계를 유동할 수 있으리라 판단된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.286-289
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• 2003

턴키공사는 설계를 도급자가 하기 때문에 설계오류로 인한 공사금액의 증액은 없다. 따라서 설계오류로 인한 공사비의 증가는 도급자의 원가율을 상승시키는 결과를 초래하고 그로인한 도급자의 채산성은 감소할 수 밖에 없는 실정이다. 또한 설계오류는 설계변경의 기간만큼 공정을 지연시키고 오류를 인식하지 못하는 경우 심각한 품질문제를 야기 시킬 수 있다. 본 연구에서는 턴키공사의 설계오류 원인을 조사하여 설계오류를 감소시킬 수 있는 방안을 제시함으로써 설계오류로 인한 원가율 상승과 공정지연, 품질저하의 문제점을 해소하고자 한다.