• 조명전기설비학회논문지
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• 제22권9호
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• pp.94-102
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• 2008

대전 관내에서 송전계통 및 배전계통의 고장발생이 없었음에도 불구하고 고압 수용가의 2차측에서 플리커(형광등 깜박거림), 엘리베이터 정지 등의 문제가 수차례 발생하였다. 순간 전압변동의 원인을 해당 변전소 캐패시터 소손, 캐패시터 투입과 OLTC 조작으로 인한 전압변동, 고조파 공진 등을 원인으로 추정하고 같은 전압변동 원인 분석을 실시하였다. 분석 개소는 정전이 발생된 변전소 모선 전압과 전류, 캐패시터 뱅크의 전압과 전류, 덕진과 항공 D/L의 전류, 세종아파트의 MOF와 엘리베이터 전용의 변압기 2차측의 전압과 전류이다. 분석결과 변전소의 캐패시터 뱅크의 콘덴서, 리액터, 방전코일의 조사 결과 열화 및 소손이 없었으며, 4차 고조파에 공진이 되도록 설정된 것도 측정을 통해 이상 없음을 확인하였다. 사고재현을 위해 이전과 동일하게 변전소 캐패시터 조작을 수행했으나 엘리베이터가 중단되는 현상이 재현되지 않았지만 고압측의 콘덴서를 투입하였을 때 수용가측의 저압변압기 2차측에서 15[%] 이상 전압이 확대됨을 확인하였다. 다양한 분석과 시뮬레이션 결과 공진에 의해 전압이 확대되었음을 규명하였다.

• Journal of Power Electronics
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• 제15권2호
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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.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2005년도 제26회 동계학술발표회 논문집
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• pp.124-139
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• 2005

In the early stage, the radio communication industry was widely accepted as a monopoly industry, so it has been controled and managed by government. But the advanced technology in Information and Technology industry has led constant increase of demand and dramatic change of communication market. Furthermore it is expected that frequency resource is to be short by market change due to wire-wireless integration. That is why the effort to utilize and manage limited frequency resource efficiently is being executed around the world. Not only newly developing and allocating the spectrum but also reallocating the existing spectrum important are, since transforming inefficiently used existing spectrum to new service can increase producer's surplus and social welfare. The economic approach to valuate the spectrum and spectrum usage right is necessary different from the traditional cost based approach, and through this approach I expect active transaction of spectrum. In this paper the real option methodology is used for valuation of spectrum, considering spectrum user's option right based on future revenue. In detail, the matter of withdrawing and reallocating the existing analog radio broadcasting spectrum is evaluated in this paper, The digitalization of a broadcasting service is widely spreaded around the world in terms of technology and service utility, and analog TV broadcasting has already been decided to be transformed to digital TV broadcasting. It was planned to convert analog radio broadcasting to DAB service before adopting DMB service, but nowadays this issue is not on the table anymore. However if the increasing demand of digital voice and broadcasting service is considered, this kind of research to valuate a spectrum is needed urgently. The result of this research shows that when the redeployment of spectrum is done, social welfare will increases. The point of the reallocation time and value are suggested by the monte carlo simulation through ROVM. In this paper, I use real option to valuate the spectrum and provide the point of the reallocation time and reasonable guideline, and moreover, the suitable information of this paper is expected to reduce risk and loss in policy practice.

• 한국산학기술학회논문지
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• 제20권10호
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• pp.47-53
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• 2019

본 연구는 기존 연구에서 초점을 맞춘 1기간 모형과는 달리 2기간 모형에서 위험회피성향의 증가에 따라 노력의 투입에 따라 손실의 크기와 발생확률이 동시에 감소하는 손실통제 노력의 변화를 살펴보고 있다. 노력의 투입과 손실의 발생시점간의 시점 분리를 고려한 본 연구의 가정은 장기에서 위험회피성향의 영향을 관찰할 수 있게 해준다. 그 결과 첫째, 손실함수 및 비용함수에 추가적인 제약이 존재했던 단기 모형인 기존 연구와는 달리 장기에서는 위험회피성향의 증가가 손실통제 노력의 증가를 가져왔다. 둘째, 손실통제 노력을 자가보험 노력 및 자가보호 노력으로 세분화해 볼 때, 위험회피성향의 증가가 자가보험 노력은 증가시키나 자가보호에 미치는 영향이 불분명하던 기존 단기모형의 결과와는 달리, 장기에서는 위험회피성향의 증가로 인해 자가보험 노력 및 자가보호 노력이 모두 증가한다는 것을 알 수 있다. 셋째, 평균이 0인 배경위험이 존재하는 경우 2기간 모형에서 위험회피성향의 증가에 따라 손실통제 노력이 증가할 충분조건은 효용함수가 신중성 조건을 나타내는 것이다.

• 한국콘텐츠학회논문지
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• 제18권11호
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• pp.430-446
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• 2018

본 논문에서는 전파자원 활용과 관련한 정책 및 투자 방안 수립에 대한 경제적 근거 및 기초자료로서의 파급 효과 분석 방법론에 관한 비교연구를 수행하였다. 정책 및 투자 방안 간 객관적 비교 및 선정을 위해 수치적 결과를 제공하는 방법론을 분석 대상으로 하였고 수학적인 모형에 기반을 둔 정량적 방법론인 계량경제모형, 산업연관분석, 연산일반균형, 시스템 다이내믹스 방법에 대해 분석 비용 등 다양한 관점에서 효용과 한계를 비교 분석하였다. 또한, 전파자원 활용의 효과 분석 측면에서 이들 방법론을 비교하고, 분석된 방법론의 장점들을 활용하고 한계를 상쇄시키기 위해 단일 방법론들을 결합한 혼합형 모형에 대한 최근 연구결과를 논의하였다. 연구결과는 전파정책 및 투자 방안 실행의 효율성 검증을 위한 다양한 분석방법 중 분석의 목적과 우선순위에 부합하는 방법을 선정하는 데 참고 지표로 활용할 수 있다.

• 한국버섯학회지
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• 제16권4호
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• pp.331-333
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• 2018

The incorporation of Shiitake culture into sawdust is a widely utilized technique that can assist in reducing the cost and time consumption associated with oak cultivation. In sawdust cultivation, browning of the surface mycelia is an important stage with respect to the utility and longevity of the sawdust media. Surface browning forms a protective coating on the substrate, which can inhibit the invasion of pathogens and suppress water evaporation. Several different light sources (red LED, white LED, blue LED, and fluorescent light) were used and the intensity of illumination was carefully controlled (1.5, 10.5, $20.5{\mu}mol/m^2s$ for LEDs and 10, 100, 300 lux for the fluorescent light) to induce browning. The light sources were regulated via a 1 h on/off cycle in a controlled room environment at a temperature of $20^{\circ}C$, 60% humidity, and 1200 ppm $CO_2$ concentration for 60days. The browning effect varied depending on the source and the intensity of illumination. This effect was most effectively induced at $1.5{\mu}mol/m^2s$ for the red and blue LEDs. All light sources induced less browning at the highest intensity of illumination. This indicates that intensity values higher than $20.5{\mu}mol/m^2s$ in the case of the LEDs and 300 lux for the fluorescent light are not effective. After harvesting of the fruit bodies, we measured the weight, length, and width of the pileus and stipe in addition to their chromaticity and hardness. Treatment with $1.5{\mu}mol/m^2s$ blue LED produced the best harvest with the highest average chromaticity, weight (21.2 g), stipe length (30.8 mm), and hardness (377.9 g), with a fine length and width of the pileus.

• 정보보호학회논문지
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• 제17권2호
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• pp.51-59
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• 2007

소프트웨어 테스팅은 소프트웨어의 버그 및 잘못 구현된 부분 등을 찾아내는 과정을 통해 품질을 평가하는 방법이다. 퍼징(fuzzing)은 소프트웨어 테스팅 기술의 여러 가지 방법 중 하나로써 난수를 발생시켜 테스팅하고자 하는 소프트웨어에 주입하는 방법으로써 보안에 중점을 두어 테스팅하는 방법이다. 퍼징은 단위 시간 당 테스팅 효율성, 비용 절감 등 여러 가지 장점을 이유로 다수 사용되고 있으나 퍼징 수행 시 전문가의 개입이 많은 단점이 존재한다. 예를 들면 해당 소프트웨어가 사용하는 프로토콜 혹은 퍼징 대상이 파일인 경우 파일 포맷에 대한 분석을 수행한 후에야 가능하기 때문에 테스팅 기간이 길어질 수 있으며 퍼징 도구를 이용해도 퍼징 대상의 프로토콜 및 포맷에 대한 분석이 난해한 경우 테스팅 대상에 대한 퍼징을 수행하지 못할 수도 있다. 본 논문에서 설계한 ROAD는 RPC 기반 프로토콜 및 소프트웨어를 자동으로 퍼징할 수 있는 도구이다. RPC는 다수의 취약점이 발견된 구성요소로써 본 논문에서는 이를 자동으로 퍼징할 수 있는 도구의 구현을 목표로 하였다. 기존의 도구 중 RPC 기반 소프트웨어를 퍼징하는 도구가 존재하지만 자동화되어 있지 않을 뿐만 아니라 소프트웨어에 따라 도구를 수정해야만 사용이 가능하다. 본 논문은 이러한 단점을 극복하고자 자동화 도구를 설계 및 구현하여 실제 RPC 기반 프로토콜 및 소프트웨어에 적용하였다. 또한 실험을 통해 도구의 효용성을 검증하였다.

• 대한물리의학회지
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• 제18권3호
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• pp.121-133
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• 2023

PURPOSE: Computerization using ICF as a protocol can enhance the assessment, communication, and decision-making of various disciplines and cultures, individual functions, disabilities and health to promote communication and understanding among various professionals, organizations, and countries. The empirical foundation for these propositions was provided by delineating of six distinct computerization components. METHODS: This study analyzed 14 papers that combined the medical field and information technology to activate the ICF through computerization. From each of these papers, distinctive advantages were extracted to propose six computerization elements. The validity of these computerization elements was examined. These papers encompass various computerization elements, among which core elements were identified. In particular, six common core elements were extracted from these papers and assumed to be strategic computerization components for ICF activation. A heuristic methodology was employed to validate these components, representing IT technology maturity using four determining indices, which were then presented graphically for validation attempts. RESULTS: Four quantified indices were defined: reliability, cost-effectiveness, support and updates, and collaboration. Using these indices, this study identified elements that leverage existing IT technologies and require new development. The possibility of increasing utility was identified by applying computerization to ICF. CONCLUSION: This study examined the strategic elements of utilizing ICF by computerizing it using a protocol concept and discussed its potential for utilization. The potential to enhance the value of information in social, physical, and cultural contexts was presented by integrating various domains and data within the ICF framework.

• 한국임상약학회지
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• 제33권3호
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• pp.168-177
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• 2023

Background & Objectives: Fixed-dose combinations (FDCs) offer advantages in adherence and cost-effectiveness compared to free combinations (FCs), but they can also complicate the prescribing process, potentially leading to therapeutic duplication (TD). This study aimed to identify the prescribing patterns of FDCs for dyslipidemia and investigate their associated risk of TD. Methods: This was a retrospective cohort study involving drugs that included statins, using Health Insurance Review & Assessment Service-National Patient Sample (HIRA-NPS) data from 2018. The unit of analysis was a prescription claim. The primary outcome was TD. The risk ratio of TD was calculated and adjusted for patient, prescriber, and the number of cardiovascular drugs prescribed using a multivariable Poisson model. Results: Our study included 252,797 FDC prescriptions and 515,666 FC prescriptions. Of the FDC group, 46.52% were male patients and 56.21% were aged 41 to 65. Ezetimibe was included in 71.61% of the FDC group, but only 0.25% of the FC group. TD occurred in 0.18% of the FDC group, and the adjusted risk ratio of TD in FDC prescriptions compared to FC was 6. 44 (95% CI 5. 30-7. 82). Conclusions: Prescribing FDCs for dyslipidemia was associated with a higher risk of TD compared to free combinations. Despite the relatively low absolute prevalence of TD, the findings underline the necessity for strategies to mitigate this risk when prescribing FDCs for dyslipidemia. Our study suggests the potential utility of Clinical Decision Support Systems and standardizing nomenclature in reducing medication errors, providing valuable insights for clinical practice and future research.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.634-639
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• 2013

The aim of the study is to develop the 3D visualization of Building Information Model and integrated 4D model for optimization of resources in the construction project. This study discuss the process of methodology and creation of 4D model of the project and simulate it to monitor the workflow at the site. Different stages of the construction process and activities are generated by using Revit and MS Project. MS project has been used for creation of the schedules and these are linked with the Revit for 3D modeling. The time used as the fourth dimension and 4D model created by using Navisworks Time liner software. Narges shopping center is presented as a case study to realize the actual uses and benefits of Building Information Model (BIM). Narges shopping mall is located in Tehran, Iran. As a part of Hekmat master plan, Narges shopping center is an 11 stores building with a total area of 30000 Sq.m. This shopping and entertainment center is comprised of 150 retails and two multi-use public halls with a capacity of 400 persons each and underground parking with total 400 parking space. The main purpose of architecture was to create an urban public center along with its revolving, spiral like form and an ever changing continuous façade by means of different colors, materials, which is in harmony with the other building of the master plan. The approximate cost of the project is $17 million and duration of the project schedule is 30 months. The developed Building Information Model enabled us to identify the potential collisions or clashes between various structural and architectural systems. 4D model has been used for limiting the interaction between subcontractors installing the different systems so rework could be avoided and productivity maximized. It is also observed that the utility of BIM for construction stimulation and clash detection is the best suitable method. Clash detection before the implementation of work is highly recommended to avoid rework.