• 대한교통학회지
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• 제5권2호
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• pp.37-54
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• 1987

The methods of the transportation plan evaluation have appearently been improved. Yet we are frequently confronted with many problems when we are trying to apply those various methods in practice. This paper aims at reviewing the major problems in the transportation plan evaluation and considering the way to resolve such kinds of problem. The selection of the evaluation criteria and the weighting systems between such criteria are the moat important things in the multi-criteria approaches. In this respect, this paper suggests some alternative evaluation criteria in consideration of the levels and the purpose of the plan. Also the increased capacities and new demands of generated trip are the main effects of the transportation investment. Nevertheless such significant effects have been neglected in the calculation of benefits due to the transportation investment in the past. Therefore this paper suggests that the surplus capacities and new demands of generated trip according to the alternative investment plans should be included in the calculation of benefits for the plan evaluation.

• 한국경영과학회지
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• 제29권4호
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.181-187
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• 2006

대규모 표본조사와 관련해서 관심변수와 보조변수간의 약한 상관관계를 고려한 Amahia et al.(1989)의 대체추정방법을 Rao-Hartley-Cocharn 추출방법에 적용해서 Rao추정량과 효율성을 비교 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.414-417
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• 2001

This paper presents the results of power flow of North-South Korea system with interconnected cases which were proposed by various present studies PSS/E and PowerWorld Simulator were used to analyze the inter connected system with several interconnected lines alternatives. The results would be very useful to select the best alternative for interconnection with considering several evaluation terms.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.199-209
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• 1998

Since most engineering problems have had open-ended and ill-defined characteristics, design process is in advance attended with determination of alternatives based on realistic constraints after definition of appropriate problem. And it is completed with selection of best alternative through their comparison and investigation, and with performance of selected-alternative's detail design. As the process of structural design compared with that of general design, this paper presents a paradigm which can generate structural design alternatives, select optimum structure among them and simultaneously set its optimum design variables in reference of several objective as a result in more extended design region. For this purpose, specialized genetic algorithms which can handle design alternatives and multicriteria problems is used.

• 대한족부족관절학회지
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• 제19권1호
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• pp.1-6
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• 2015

Total ankle replacement has been performed for treatment of end stage arthritis of the ankle, hopefully being an alternative to ankle arthrodesis. However, due to its high failure rates, earlier versions of ankle replacements were not regarded as successful procedures. The latest design has shown increasingly positive results. Total joint replacement of the ankle itself is still regarded as a demanding procedure and much more challenging than that of the hip and knee in many aspects. Several studies, however, have pointed out that it is becoming the viable, accepted alternative for arthrodesis with advanced implants, appropriate patient selection, and proper training experience of procedures. Compared with arthrodesis, it shows equal or better outcomes in pain relief, range of motion, and patient's satisfaction. We are attempting to review its biomechanical characteristics, implant design, indications, complications, clinical outcomes, and survival rate.

• 산업공학
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• 제12권1호
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• pp.43-48
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• 1999

This paper indicates deficiencies of existing weighting methods for decision problems that require trading off a selection of one alternative against others. Deficiencies originate from the definition of weight, $W_i$, satisfying that $W_i{\geq}0$ for all i and sums up to one and an assumption of independence between attributes. Thus, existing weighting methods can not handle a situation where all attributes are interrelated, resulting in that attributes can give either positive, or negative, contributions to the value of an alternative. In order to cope with deficiencies, this paper redefines weight and proposes a new causally related weighting method. The proposed method was applied in the study of developing a comprehensive organizational performance measurement system and showed a good performance.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권1호
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• pp.40-49
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• 2000

The capillary tube performance for R-407C is experimentally investigated. The experimental setup is a real vapor-compression refrigerating system. Mass flow rate is measured for various diameter and length while inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rate of the numerical model is about 14% less than the measured mass flow rate. It is found that mass flow rate and length for R-407C are less than those for R-22 under the same condition. Based on this experimental study and the numerical model, a set of design charts for capillary tube of R-407C is proposed.

• 한국국방경영분석학회지
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• 제28권1호
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• pp.83-96
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• 2002

The Analytic Hierarchy Process (AHP) is well suited to group decision making and offers numerous benefits as a synthesizing mechanism in group decisions. To date, the majority of AHP applications have been in group settings. One reason for this may be that groups often have an advantage over individual when there exists a significant difference between the importance of quality in the decision and the importance of time in which to obtain the decision. Another reason may be the best alternative is selected by comparing alternative solutions, testing against selected criteria, a task ideally suited for AHP. In general, aggregation methods employed in group AHP can be largely classified into two methods: geometric mean method and (weighted) arithmetic mean method. In a situation where there do not exist clear guidelines for selection between them, two methods do not always guarantee the same group decision result. We propose a simulation approach for building group consensus without efforts to make point estimates from individual diverse preference judgments, displaying possible disagreements as is natural in group members'different viewpoints.

• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1007-1021
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• 2022

Autonomous driving of unmanned aerial vehicles may have to pay expensive cost to create and switch new routes if unexpected obstacles exist or local map updates occured by the control system due to incorrect route information. Integrating digital twins into the path-following process requires more computing resources to quickly switch the wrong path to an alternative path, but it can quickly update the path during flight. In this study, we design a DEVS-based simulation environment which can modify optimized paths through short-term simulation of multi-virtual UAVs for applying digital twin concepts to path follow. Through simulation, we confirmed the possibility of increasing the mission stability of UAV.