• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2012년도 한국컴퓨터종합학술대회논문집 Vol.39 No.1(D)
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• pp.265-267
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• 2012

This paper analyzes network selection issues of secondary users (SUs) in Cooperative Cognitive Radio Networks (CRNs) by utilizing Queuing Model. Coordinating with Handover Cost-Based Network selection, this paper also addresses an opportunity for the secondary users (SUs) to enhance QoS as well as economics efficiency. In this paper, network selection of SUs is the optimal association between Overall System Time Minimization Problem evaluation of Secondary Connection (SC) and Handover Cost-Based Network selection. This will be illustrated by simulation results.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.469-472
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• 2000

Replacement policy of a degradation of system is investigated by incorporating the loss function defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost . Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspect ion period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function, inspection cost, respectively. As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspect ion cost is observed to be insensitive.

• 한국구조물진단유지관리공학회 논문집
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• 제6권4호
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• pp.189-199
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• 2002

This study is intended to propose a systematic procedure for the development of the conditional assessment based on the safety of structures and the cost effective performance criteria for designing and upgrading of bridge structures. As a result, a set of cost function models for a life cycle cost analysis of bridge structures is proposed and thus the expected total life cycle costs (ETLCC) including initial (design, testing and construction) costs and direct/indirect damage costs considering repair and replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses costs. Also, the optimum safety indices are presented based on the expected total cost minimization function using only three parameters of the failure cost to the initial cost (${\tau}$), the extent of increased initial cost by improvement of safety (${\nu}$) and the order of an initial cost function (n). Through the enough numerical invetigations, we can positively conclude that the proposed optimum design procedure for bridge structures based on the ETLCC will lead to more rational, economical and safer design.

• 대한산업공학회지
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• 제31권3호
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• pp.248-256
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• 2005

In this paper, we compare two EOQ based inventory models under total cost minimization and profit maximization to investigate the difference in the optimal solutions. First of all, optimal solutions for both models through geometric programming (GP) techniques are found considering production (lot sizing) as well as marketing (pricing) decisions. An investigation of the effects of the changes in the optimal solutions according to varied parameters is performed by studying optimality conditions as well as by performing numerical analysis. We then conduct comparative analysis between the models to show the relationships between the optimal solutions of the models where certain conditions in the cost per unit and the demand per unit time are given. Several interesting economic implications and managerial insights are observed from this analysis.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.812-819
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• 2014

The proposed technical work attempts to compare the two key technologies of power distribution, i.e. direct current (DC) and alternating current (AC) in a fiscal manner. The DC versus AC debate has been around since the earliest days of electric power. Here, at least four types of a low voltage DC (LVDC) distribution are examined as an alternative to the existing medium voltage AC (MVAC) distribution with an economic assessment technique for a project investment. Besides, the sensitivity analysis will be incorporated in the overall economic analysis model to cover uncertainties of the input data. A detailed feasibility study indicates that many of the common benefits claimed for an LVDC distribution will continue to grow more profoundly as it is foreseen to arise with the increased integration of renewable energy sources and the proliferation of energy storage associated with the enhanced utilization of uninterruptible power supply (UPS) systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1816-1819
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• 2003

As a result of milling operation, we expect to have burr at the outward edge of workpiece. Also, it causes undesirable problems such as deburring cost, low quality of machined surface, and bottleneck in manufacturing process. Though it is impossible to totally remove burr in machining, it is necessary to plan a machining process that minimizes the occurrence of burr. In this paper, a scheme is proposed which identifies the tool path of the milling operation with minimum burr. In the previous research, a Burr Expert System was developed where the feature identification, the cutting condition identification, and the analysis on exit burr formation are the key steps in the program. The Burr Expert System predicts which portion of workpiece would have the exit burr in advance so that we can calculate the burr length of each milling operation. Here, the critical angle determines whether the burr analyzed is an exit burr or not. So the burr minimization scheme becomes to minimize the burr with critical angle. By iterating all the possible tool paths in certain milling operation, we can identify the tool path with minimum burr.

• 환경정책연구
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• 제5권4호
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• pp.107-126
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• 2006

위협으로 뒷받침되는 강제된 자발적 협약은 정부가 원하는 재활용 목표를 최소비용으로 재활용할 수 있게 한다. 이 논문에서는 재활용에 관한 정부와 산업계의 자발적 협약을 경기(game)상황으로 이해하고 경기의 균형이 존재하는지 그리고 그 균형은 관련 산업 전체의 비용최소화를 보장하는지 검토하였다. 먼저 업계 전체를 당사자로 하여 대표인 협회와 정부 간의 쌍무 협약에 있어서 협약 참가자의 전략을 검토하고 업계의 비용최소화 전략이 Nash 균형 (SPNE)인지 여부를 판정함으로써 정부에서 기대하는 비용최소화 조건을 충족시키는지 검증하였다. 다음에는 협회와 회원 기업 간의 다자간 협약을 바탕으로 무임승차가 존재하는 경우와 그렇지 않은 경우로 나누어 개별 기업의 비용최소화 전략이 어떻게 균형을 가져오게 되는지 검토하였으며 마지막으로 이러한 이론적 분석결과가 현실의 정책평가에 어떻게 활용될 수 있는지 그 가능성을 검토하여 보았다.

• 한국정보처리학회논문지
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• 제5권9호
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• pp.2395-2403
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• 1998

메모리 할당은 두 개의 독립적인 목표가 있다. 즉, 메모리 개수를 최소화하는 것과 한 개의 메모리 내의 레지스터(즉 단어)수를 최소화시키는 것이다. 우리의 관심은 메모리 할당시 이들 바인딩이 일어나는 순서에 있다. 바인딩이 일어나는 순서를 변경하여 세 가지의 전혀 다른 메모리 할당 알고리즘을 만들고 이들을 분석하였다. 실험 결과 경험적 비용 함수를 도입하여 부분 작업을 동시에 실행시켰을 때 메모리 면적을 최대 20%까지 줄일 수 있음을 확인하였다.

• 대한간호학회지
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• 제38권3호
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• pp.363-371
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• 2008

Purpose: This analysis was conducted to evaluate the cost-effectiveness of gemcitabine-cisplatin chemotherapy for non small-cell lung cancer patients in an outpatient setting compared with the traditional inpatient setting. Methods: A cost-effective analysis was conducted from a societal perspective. The effects of treatment, which was measured as an adverse event rate, were abstracted from a published literature search and empirical data from one university hospital. The costs included both direct and indirect costs. Direct costs included hospitalizations, outpatient visits, and lab tests. Pharmaceutical costs were excluded in analysis because they were same for both options. Indirect costs included productivity loss of patients as well as care-givers. In order to determine the robustness of the results, sensitivity analysis on treatment protocol was conducted. Results: Literature search showed no difference in adverse effect rates between inpatient treatment protocol and outpatient treatment protocol. Therefore, this analysis is a cost-minimization analysis. Cost-savings in the outpatient setting was 555,936 won for one treatment cycle. Our sensitivity analysis indicated that the outpatient chemotherapy still showed cost-savings, regardless of changes in treatment protocol. Conclusion: The outpatient gemcitabine-cisplatin chemotherapy for non small-cell lung cancer resulted in cost savings compared to inpatient chemotherapy. More importantly, outpatient chemotherapy could improve the utilization of health service resources in terms of available beds.

• 대한교통학회지
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• 제25권6호
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• pp.209-230
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• 2007

이 논문은 혼잡현상을 갖는 교통체계의 사회비용함수를 사회비용 최소화문제로부터 도출하여 분석하였다. 이 논문은 이 분야의 기존 연구에서 다루지 않았던 다음의 두 가지를 중점적으로 분석하였다. 하나는 이용자들의 시간가치가 다를 경우에 비용함수의 구조가 어떻게 달라지는지를 검토하는 것이고, 다른 하나는 사회비용함수를 구성하는 공급자 비용함수의 구조를 파악하는 것이었다. 분석의 결과는 다음과 같이 요약될 수 있다. 첫째, 한계사회비용은 특정한 시간가치를 가진 고객이 소비한 시간가치비용과 추가 고객의 처리에 수반되는 시스템 전체의 서비스시간 증가에 따른 한계혼잡비용으로 구성된다. 둘째, 한계혼잡비용은 공급자의 보상한계비용과 같은 바, 후자는 공급자가 추가의 고객을 가장 경제적으로 처리함에 필요한 용량의 변경에 의한 서비스시간의 변화 양에 대한 이용자 전체의 시간가치를 보상해준다는 전제아래서의 공급자 한계비용을 지칭한다. 셋째, 보상한계비용은 서비스시간함수가 산출과 용량에 대해 동차함수일 경우 한계용량비용에 시스템 이용률의 역수를 곱한 값과 같다.