• Journal of Korea Port Economic Association
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• v.26 no.2
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• pp.58-81
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• 2010

The economic appraisal of a port remodeling project must be transparent and persuasive to the public over the entire stage of the project. A project evaluator need to be familiar with the guidelines on evaluation, and to do his best to follow the guidelines to evaluate the given project. To make the right decision on investment, the evaluator must take into consideration not only economic efficiency, but also equity issues such as income redistribution and balanced development between regions. Port remodeling projects tend to produce externalities to the environment. However, these externalities are of qualitative nature, and hard to measure in monetary terms, so these are liable to be ignored in the process of project evaluation. Two different approaches - RP(revealed preference) and SP(stated preference) have been tried to assess the value of these non-market goods. Government authorities need to set minimum guidelines which project evaluators must follow in order to make the evaluation more reliable.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.51-60
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• 2011

The study explored a way to analyze return-on-investment for evaluating corporate e-learning programs. It is said to be not easy to measure return-on-investment due to complexity of determining exact amount of cost and benefit of any e-learning program. In this vein, it has been rare to see researches regarding return-on-investment for corporate e-learning programs. Nevertheless, it is needed to try to document return-on-investment evidence for verifying effectiveness of the programs. More concretely, the purpose of the study is to draw up guidelines in making decisions about whether companies should invest in e-learning programs any more at particular point of time.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.1-8
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• 2005

In this paper, we study a call admission control algorithm for supporting multicast service under the BcN environment where broadcasting, communication and Internet are converging to be one. It is necessary to control service requests with a certain criteria in order to guarantee QoS because the system capacity is limited. As a possible solution, we divide one multicast service into 3 classes and set up a threshold per each class to control service request. Especially, for the purpose of system benefit, we define system pay-off rate 'GAIN' with the term 'Reward' and 'Penalty' according to admit and reject service request. And we confine the range of threshold which makes GAIN to be maximized. For the performance analysis, we model the system as M/M/m/m queueing system, investigate GAIN under various conditions and show the effectiveness of the proposed algorithm.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.21-27
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• 2016

Big Data is gathering all the attention from every business community. Pervasive use of machine-to-machine (M2M) applications and mobile devices bring an explosion of data. By analyzing this data, the private and public sectors can benefit in the areas of cost reduction and productivity. The Korean government is actively pursuing Big Data initiatives to promote its usage. This paper aims to select industries which fit for the development of Big Data with a verification of the experts. The analytic hierarchy process (AHP) is applied to systematically derive the opinion of more than 50 professionals. Medical / welfare, transportation / warehousing, information and communications / information security, energy, the financial sector have been identified as promising industries. The results can be utilized in developing Big Data best practices thus contributing industrial development.

• Journal of Power Electronics
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• v.15 no.2
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• pp.455-468
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• 2015

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.272-274
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• 2004

양방향입찰시장(TWBP)의 도입을 위해서는 이를 위한 시장설계 및 효율적인 시장운영을 위한 다양한 분석 작업들이 요구되고 있다. 특히 시장설계의 경우, 해외 자문회사와의 협력을 통해 경쟁적 전력시장을 이미 도입하여 운영하고 있는 해외 국가들의 사례들을 포함한 많은 시장운영 기법들이 검토되고 있으며 향후 도입될 TWBP 전력시장에 적합한 방안들을 준비하고 있다. 전력을 전력시장운영규칙이 정하는 바에 따라 전력시장을 통해서만 거래하도록 규정하고 있는 우리나라의 경우, 전력시장운영규칙은 전력시장과 전력계통의 운영에 대한 모든 것을 다루게 되는 만큼 이에 대한 합리적인 설계와 적용은 효율적인 TWBP 전력시장의 기본 틀이라고 할 수 있다. 양방향입찰시장에서의 가격결정은 전력수급과 시장가격 안정화를 위해 매우 중요한 사안이다. 또한 현재 CBP시장과 다른 용량요금(CP)제도의 폐지와 기타 공급예비력확보 제도 등 도매시장설계에 있어 중요한 자료를 제공한다. 양방향입찰시장하에서 가격수준 분석을 통해 시장개설 이전에 문제점을 사전에 검토하여 문제점을 개선하고 시장규칙에 반영하여야 한다. 또한 용량요금 폐지에 따른 보완대책을 수립하여 수급불안정을 방지하고 전력시장 안정화와 성공적인 도매경쟁시장 개설을 위해 필수적이라 할 수 있다. 본 논문에서는 CBP 시장과 TWBP 시장에서의 기본적 가격예측을 위한 구조적 모델링과 일부 시나리오에 대한 결과를 소개하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.216-220
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• 2012

본 연구는 경기도 용인시에 위치한 공공하수처리장을 대상으로 소수력발전 성능특성을 예측하고 경제성을 분석하여 소수력발전소의 건설타당성을 제시하였다. 방류구에서의 수준측량 조사에 따르면 실제 유효 낙차는 4.3m로 나타났다. 최근 5년간 방류량 자료를 살펴보면 일평균 실제 처리량은 약 $30,000m^3/day$로 나타났으며, 우수 유입과 물 사용량이 증가하는 여름 및 가을에 처리량이 증가하였다. 설계유량은 유량변화에 따른 누적 확률밀도와 유량지속곡선에 근거해 산정하였으며, 시간빈도로 보았을 때 17%의 유량이 지속되는 $0.35m^3/sec$가 설계유량으로 나타났다. 예상되는 수차 발전용량은 11kW급이며, 시스템 가동율은 74%, 그리고 계통선에 송출될 수 있는 연 전력생산량은 71.3MWh로 나타났다. 경제성 평가는 신재생에너지 경제성 분석 도구인 RETScreen 프로그램을 사용하여 B/C ratio, IRR, 개발투자비 등의 경제성 평가지표들을 산정하였다. 편익(Benefit) 산정시 전력기준단가는 133.67원/kWh, 할인율 7%를 적용하였으며, 비용(Cost) 산정시 유지관리비는 초기 건설비의 1%, 사용연한 30년을 적용하였다. 경제성 분석결과 기흥레스피아의 소수력발전소 건설시 초기 건설공사비가 $165,000 일 때, B/C 1.0, NPV $3,534, 투자회수기간 15.1년으로 산정되었고 따라서 초기 건설비용이 $165,000 이하일 때 가장 경제적인 것으로 파악되었다.

• Journal of Korean Society of Transportation
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• v.23 no.1
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• pp.55-66
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• 2005

Association of South East Asian Nations(ASEAN) has recently decided to develop ASEAN Highway Network to connect member countries by road in an attempt to achieve a goal of closer economic integration in the region. This entailed the necessity to newly construct or upgrade some 5,481 km of road sections to make ASEAN Highway Network functional. This study offers haw we can prioritize development of these road sections using the Analytic Hierarchy Process. Particularly, it shows how individual road sections can be prioritized considering the importance of corridor or road group where the individual road section lies. It also develops how values of different evaluation criteria can be compared in the same scale. This new approach can be useful in prioritizing highway development in such cases where candidate road sections are widely scattered around the region, so detailed benefit and cost analysis is practically too demanding to carry out.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.235-241
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• 2001

Objective : Controversy exists which surgical treatment better in lumbar grade I spondylolisthesis, decompressive laminectomy with or without lumbar instrumentation. Methods : Out of Sixty-four patients with lumbar spondylolisthesis underwent surgery, 18 patients operated with decompressive laminectomy alone and 44 patients with decompession and lumbar instrument, during recent 5-years between January, 1994 and December, 1998. The author studied a long term follow-up in the above two groups to analyzing the overall clinical outcomes in each group and to determining the incidence of pos-toperative radiologic instability. Results : 1) Overall postoperative symptoms improvement were not so different in both groups. 2) Postoperative progressive subluxation is more common after decompressive laminectomy without instrumentation than with instrumentation group. 3) Overall clinical outcomes were slightly better in decompressive laminectomy without instrumentation than with instrumentation group but there was no significant difference. 4) Postoperative radiologic changes did not seem to influence the patient-reported clinical outcomes. 5) Postoperative complications is more common in decompressive laminectomy with instrumentation group than without instrumentation group. Conclusion : In the surgical management of grade I spondylolisthesis, the efficiency and superiority of surgical treatments requires the cost effectiveness and risk/benefit analysis of decompressive laminectomy with or without instrumentation. Therefore, Further detailed studies of long term follow up in a large number of patients in each group are needed for choice of best treatment.

• Osong Public Health and Research Perspectives
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• v.9 no.6
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• pp.314-324
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• 2018

Objectives: The aim of this study was to analyze research and development projects in mental health services in Korea, using priority evaluation of mental health promotion policies to determine direction of the service. Methods: An online survey was conducted that targeted experts in the mental health service regarding promotion of mental health in Korea in 2016. The survey was based on 32 policy projects that resulted from 12 strategies according to 4 policy objectives. Results: Analysis of 32 mental health projects were assessed regarding the possibility of technology development success, magnitude of the ripple effect, and necessity of a national response. It was observed that 3 policy projects relevant to suicide, had a high relative priority. This was followed by policies for improvement of health insurance and the medical benefit cost system, and policies for reinforcement of crisis psychological support such as those for disaster victims. Conclusion: The prioritization of mental health services should place an emphasis on promotion of a healthy mental lifestyle, rehabilitation support for patients with serious mental illness, and reinforcement of social safety networks for suicide prevention.