• 산업경영시스템학회지
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• 제32권3호
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• pp.142-158
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• 2009

The supplier selection problem is perhaps the most important component of the purchasing function. Some of the common and influential criteria in the selection of a supplier include quality, price, delivery, and service. These evaluation criteria often conflict, however, and it is frequently impossible to find a supplier that excels in all areas. In addition, some of the criteria are quantitative and some are qualitative. Thus, a methodology is needed that can capture both subjective and objective evaluation measures. The Analytic Hierarchy Process(AHP) is a decision-making method for ranking alternative courses of action when multiple criteria must be considered. This paper proposes the AHP-based approach which can structure the supplier selection process and the achievements-based procedure which can allocate order quantities for the selected suppliers In automotive part manufacturers. Also, through the practical case of 'D' automotive part manufacturing company, we shows that the proposed AHP based supplier selection approach and the achievements-based allocation procedure of order quantity can be successfully applied for supplier selection and order quantity allocation problems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.855-859
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• 2009

In this paper, we introduce the estimation method by Risk or SIL(Safety Integrity Level) for the criterion of safety assurance and summarize each application method and target. IEC 62278(EN 50126) which is international standard for the specification and verification of the railway system RAMS indicate a criterion of safety assurance. Especially, it recommend the safety verification by continuous verification as the order of requirement establishment, design, manufacture, installation, operation, and maintenance for the equipment not easy to quantify the operation environment. In this paper, we study the SIL requirement allocation method relating to internal new system development and existing system improvement by analysing SIL recommendations which were used to understand SIL for a train control equipment in 1990s in IRSE and theoretically their allocation background. This paper help the safety management of Korea train control system to develope the quantitative management procedure as international level by analyzing the SIL requirement allocation by operation agency and the right SIL verification procedure by manufacture and indicating the example to assure safety because it is necessary for improvement and localization for the Korea train control system having highly dependence on aboard technology.

• Advances in Energy Research
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• 제6권1호
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• pp.55-73
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• 2019

The cost incurred by voltage sag effect in power networks has always been of important concern for discussions. Due to the environmental constraints, fossil fuel shortage crisis and low efficiency of conventional power plants, decentralized generation and renewable based DG have become trends in recent decades; because DGs can reduce the voltage sag effect in distribution networks noticeably; therefore, optimum allocation of DGs in order to maximize their effectiveness is highly important in order to maximize their effectiveness. In this paper, a new method is proposed for calculating the cost incurred by voltage sag effect in power networks. Thus, a new objective function is provided that comprehends technical standards as minimization of the cost incurred by voltage sag effect, active power losses and economic criterion as the installation and maintenance costs of DGs. Considering operational constraints of the system, the optimum allocation of DGs is a constrained optimization problem in which Lightning Attachment procedure optimization (LAPO) is used to resolve it and is the optimum number, size and location of DGs are determined in IEEE 33 bus test system and IEEE 34 bus test system. The results show that optimum allocation of DGs not only reduces the cost incurred by voltage sag effect, but also improves the other characteristics of the system.

• 한국구조물진단유지관리공학회 논문집
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• 제10권3호
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• pp.123-134
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• 2006

본 연구에서는 해상교량의 선박충돌 해석을 위한 설계선박을 결정하기 위한 선박충돌 위험도 분석을 수행하였다. 확률기반 해석과정을 포함하는 Method II를 이용하여 선박충돌 위험도 해석결과로부터 선박충돌에 대한 설계선박을 선정하였다. 계산연간파괴빈도와 허용기준을 반복 비교하는 해석과정에서는 연간파괴빈도 허용기준의 분배방법이 포함된다. 주탑집중 분배방법이 주탑에 비해 과대평가되는 교각의 설계 수평내하력을 적절히 수정할 경우에는 보다 경제적인 결과를 가져오지만, 교량부재의 중요도를 고려한 가중치에 의한 분배방법이 설계인자의 특성들을 정량적으로 고려하기 때문에 보다 합리적인 것으로 보인다. 선박충돌에 노출된 교각 각각에 대한 선박충돌위험도 평가로부터 교량의 대표 설계선박이 선정되었다. 설계선박은 같은 교량에서도 선박통행량 특성에 따라 많은 차이가 있다.

• 대한전기학회논문지:전력기술부문A
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• 제54권10호
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• pp.496-499
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• 2005

In many parts of the world, the electric power industry is undergoing unprecedented changes. Therefore, in order to reform the electric power industry efficiently and minimize the confusion of this restructuring, the systematic studies related to transmission pricing and transmission cost allocation issues are required essentially. However, even now, the basis of transmission cost allocation rate is not equipped so that the regulation body has determined the allocating rate under the common practice. In this paper, we demonstrate that the decision of transmission cost allocation rate is the regulation body's own right. For this analysis, we apply game theory to the procedure determining this rate and the competition to determine this rate between gencos and distcos is modeled as the arbitration game.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.351-354
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• 2005

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of the maritime bridge. Method II which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. The AF allocation by weights seems to be more reasonable than the pylon concentration allocation method because this AF allocation takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified.

• ETRI Journal
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• 제29권4호
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• pp.445-451
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• 2007

An adaptive modulation scheme is presented for multiuser orthogonal frequency-division multiplexing systems. The aim of the scheme is to minimize the total transmit power with a constraint on the transmission rate for users, assuming knowledge of the instantaneous channel gains for all users using a combined bit-loading and subcarrier allocation algorithm. The subcarrier allocation algorithm identifies the appropriate assignment of subcarriers to the users, while the bit-loading algorithm determines the number of bits given to each subcarrier. The proposed bit-loading algorithm is derived from the geometric progression of the additional transmission power required by the subcarriers and the arithmetic-geometric means inequality. This algorithm has a simple procedure and low computational complexity. A heuristic approach is also used for the subcarrier allocation algorithm, providing a trade-off between complexity and performance. Numerical results demonstrate that the proposed algorithms provide comparable performance with existing algorithms with low computational cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.375-377
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• 2002

In many parts of the world. the electricity industry is undergoing unprecedented changes. Hence, in order to reform the electricity industry readily and efficiently and minimize the confusion by these restructuring, it is required the systematic studies related to transmission pricing and transmission cost allocation issues. However, even now the basis of transmission cost allocation rate is not equipped so that the regulation body has determined the allocating rate under the common practice. In this paper it is demonstrated that the decision of transmission cost allocation rate is the regulation body's own right. For the analysis, game theory is applied to the procedure determining this rate and the competition to determine this rate between generators and distributors is modeled as the arbitration game.

• 대한인간공학회지
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• 제23권1호
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• pp.49-63
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• 2004

In this study. differences in attention allocation patterns between expert and novIce pilots were investigated by a verbal protocol when pilots were engaged in a task during the instrument flight. Ten pilots including experts and novices were participated to conduct a pre-determined task(a fix-to-fix) on F-5E Cockpit Procedure Trainer Simulator. Experts show better performance as expected with more stable variations in speed. altitude. and attitude. In attention allocation patterns. novices allocated about 83% of attentional resources on the primary instruments (airspeed indicator. altitude indicator. and attitude) relating to the task of the basic flight while experts spent 57%. This difference in the availability of attentional resources allowed expert pilots to accomplish the task better than novices. In other words. training a pilot should consider a program for building up wider instrument scanning patterns to become an expert in a shorter time.

• Management Science and Financial Engineering
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• 제2권1호
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• pp.19-51
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• 1996

We suggest a distributed framework for task assignment in the computer-controlled shop floor where each of the resource agents and part agents acts like an independent profit maker. The job allocation problem is formulated as a linear programming problem. The LP formulation is analyzed to provide a rationale for the distributed task assignment procedure. We suggest an auction based negotiation procedure including a price-based bid construction and a price revising mechanism. The performance of the suggested procedure is compared with those of an LP formulation and conventional dispatching procedures by simulation experiments.