• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.44-48
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• 1998

In the buck-boost DC-DC converter which is used at a certain situation such as in factories where loads often change a lot, the switches in the device make big energy loss in operating at Buck-Boost Mode due to hard switching and are affected by lots of stresses which decrease the efficiency rate of the converter. In order to improve this problem, to decrease the loss of snubber and switching, it has been investigated that zero voltage switching mode and zero current switching mode which make the operation of switches with soft switching. For the more sophisticated and advanced device, this paper is presented the Partial Resonant Soft Switching Mode Power Converter which is adapted the power converter having the partial resonant soft switching mode, that makes switches operate when the resonant current or voltage becomes zero by making the resonant circuit partially at turning on and off of the switches with suitable layout of the resonant elements and switch elements in the converter. Also, this paper includes the analysis and simulation of the Partial Resonant type Buck-Boost Chopper.

• Asian-Australasian Journal of Animal Sciences
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• 제2권1호
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• pp.43-49
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• 1989

In spite of the well confirmed advantages of wilting on the fermentation quality, wilting silages are difficult to make at optimum dry matter content. The prolonged wilting, especially in humid condition, result in lower water soluble carbohydrate (WSC) contents, extensive protein breakdown and sometimes higher total volatile fatty acid (VFA) during wilting an ensilage. Apart from difficulty of controlling moisture content, another problem associated with wilted silages is different evaluation on the potential productivity. In temperature climate of Asia, therefore further researches on the effects of wilting on the silage fermentation and potential productivity seen to be necessary.

• 한국응용과학기술학회지
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• 제33권1호
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• pp.213-223
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• 2016

The validity of landfill gas models is an important problem considering that they are frequently used for landfill-site-related policy making and energy recovery planning. In this study, the Monte Carlo method was applied to an landfill gas generation model in order to enhance conformity. Results show that the relative mean deviation between measured data and modeled results (MD) decreased from 19.8% to 11.7% after applying the uncertainty range of Intergovernmental Panel on Climate Change (IPCC) to the methane-generation potential and reaction constants. Additionally, when let reaction constant adjust derived errors from all other modeling components, such as model logic, gauging waste, and measured methane data, MD decreased to 6.6% and the disparity in total methane generation quantity to 2.1%.

• 한국컴퓨터정보학회논문지
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• 제20권10호
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• pp.113-119
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• 2015

In this paper, we propose an efficient freedom of information and Information access right which improves transparent and speedy administration process. To build open Information, we scrutinize that causes of non access right and change of civil service consciousness, attitude for open information by effectively open system circumstances. The Important thing is basic information that is available to the public through an agency's FOIA Reference Guide, all agencies must notify potential FOIA requesters of the formal rules and requirements for the making and handling of FOIA request, through their FOIA regulations. The characteristics of this paper focused on Information access right, causes of non access right and proposed policy. In this paper, The author emphasize are as follows: first, to examine freedom of information' necessity and problem that scrutinize a theoretic analysis, second, to understand civil servant's attitude for the freedom of information, third, to suggest action plan and agenda for the better of Good Governance and Democracy of information.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.144-147
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• 1993

The long-term electricity resource planning of electric utility has undergone significant change during the past decade. The current resource planning can be considered as multi-objective decision making procedure under the various uncertainties such as demand growth, construction cost, fuel price, environmental regulation, plant site, financial adequacy, new technology advent and so on. This paper presents a standardized electricity resource planning scheme using the strategic planning concept. EGEAS computer model was fully applied to indentify feasible alternative plans and simulate various attribute values corresponding each alternative plan and future. As a case study, a hypothetical long-ten capacity expansion planning problem is analyzed.

• 한국수자원학회논문집
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• 제46권2호
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• pp.99-109
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• 2013

유역 환경에 대한 복잡성의 증가는 단일 의사결정자들이 의사결정문제의 모든 부분을 고려하는 것을 점점 더 불가능하게 만들기 때문에 불확실성은 더욱 증가하게 된다. 따라서 본 연구는 그룹의사결정기법을 사용하여 우리나라 공간적인 홍수 취약성을 정량화하는 접근법을 제시하였다. 개인의 선호도를 분석하기위해 Fuzzy TOPSIS를 사용하였고 개인선호도의 통합을 위해 Borda count, Condorcet 그리고 Copeland 방법을 사용하였다. 마지막으로 도출된 결과를 Fuzzy TOPSIS 및 TOPSIS의 결과와 비교하였고 스피어만 순위상관계수와 켄달의 순위상관계수, Emond와 Mason이 제시한 순위상관분석을 이용하여 순위의 일치성을 검토하였다. 그 결과 일부 지역의 취약성 순위가 큰 폭으로 역전되는 현상을 보였다. 그룹의사결정 개념을 반영하여 지역별 취약성을 산정할 경우 우선순위의 변동이 클 수 있으므로 홍수 취약성 산정시 본 연구에서 제시된 모델을 고려할 필요가 있다.

• 한국가정과교육학회지
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• 제31권3호
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• pp.91-116
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• 2019

이 연구는 문헌 고찰을 통해 체인지메이커 교육의 의미를 살펴보고, 가정과 수업에 맞는 체인지메이커 교육 프로그램을 개발한 후 이를 적용한 학습자의 성장에 관한 사례를 통해 가정교과에서의 체인지메이커 교육의 의의에 대해 알아보고자 하였다. 이를 위해서 먼저 체인지메이커 교육에 대한 개념을 정의하였다. 체인지메이커 교육이란, 실생활 속에서 우리가 직면하는 문제들에 대해 생각하고(Thinking), 배우고(Education), 만들고(Making), 참여하고(Participation) 즐기며(Play) 다양한 문제해결 방안을 도출하고 서로 공유(Share)하여 변화(Change)시키는 교육을 말한다. 둘째, 본 연구에서는 가정교과에서의 체인지메이커 교육의 방향을 "폭넓은 메이커 활동을 통해 사회 문제에 관심을 가지고 문제를 해결하고 타인과 공감, 협업하여 행복하고 건강한 가정생활과 직업생활을 주도적으로 영위할 수 있도록 하는 것"으로 하고 내용의 범위를 "아동 가족, 식생활, 의생활, 주생활, 소비생활의 5개의 영역의 내용 요소를 추출하여 이를 교육할 수 있는 세부 주제를 선정"하고 교육 방법으로 "주제별로 TEMPS 단계를 통해 교과의 목적을 달성할 수 있도록 한다."로 제안하였다. 셋째, 체인지메이커 프로그램의 설계는 체인지메이커 교육의 5가지 핵심 아이디어 중에서 TEMPS를 단계로 프로그램을 설계하였다. T(Thinking)는 문제에 대해 파악하고 해결방법을 생각하는 단계이고, E(Education)는 다음 단계(Making)를 위한 배경지식을 얻는 단계이다. M(Making)은 문제 해결을 위해 필요한 목표물을 만드는 단계이고, P(Participation)와 P(Play)는 참여하고 즐기는 단계이다. S(Share)는 결과물 전시, SNS공유, 수업 발표회 등을 통해 교육적으로 확산을 시켜 궁극적으로 사회를 변화(Change)시키는 단계이다. 본 연구에서는 TEMPS 단계를 기본으로 하여 중학교 12개 프로그램, 고등학교 15개 프로그램을 개발하였고, 프로그램 당 각각 2차시~12차시로 중학교 총 68차시, 고등학교 총 68차시 분량이다. 체인지메이커 프로그램에 1년 간(2018년 3월 2일~2018년 12월 31일) 참여한 학습자들은 삶과 교육의 연계, 실천 능력의 향상, 자기 주도 학습, 자존감 향상, 성취감과 자기 성찰, 비판적 인식 향상, 감각적인 관찰 등에서 긍정적인 성장을 보여주었다.

• KIEAE Journal
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• 제9권5호
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• pp.85-96
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• 2009

This study analyzed a characteristic by types of urban regeneration helping the establishment of urban identity under social condition change. It will be foundation of sustainable urban development with strategy that secures world-wide competitive power. For this, sample cases that established identity from urban regeneration were reviewed about the main subject and the supporting subject in business side and hardware, software, system, and finance in design factors. 4samples each in inheritance intensification type and change creation type were selected and analyzed. The result said it is most effective to establish urban identity when inheritance intensification type is the private-centered for urban regeneration. And it is better to do the project that the main subject and the supporting subject are taken by the private or the private-leading partnership. It is necessary to manage the region and plan events with software design factors more than hardware design factors. In addition, for urban identity, it was found to be desirable to utilize and preserve fully current resources such as historical scenery and activate the communities than making new facilities. On the contrary, the project based on change creation type needs to be under the public management with innovative idea. Also, when it comes to design factors, facilities related to culture and art and community spaces should open and run actively. It is important for the region to improve its image by New design style such as TOD. In software side, it is important to manage the region by monitoring about urban regeneration business and solve social mix and employment problem. On the other hand, in terms of system and administration, both types don't show a difference in urban identity establishment, since it is same that both should make partnership and get a support of subsidy to be most effective.

• 한국안전학회지
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• 제26권1호
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• pp.1-7
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• 2011

When the pumps stopped in the operation by the power failure, the hydraulic transients take place in the sudden change of a velocity of pipe line. Each and every water hammer problem shows the critical stage to be greatly affected the facts of safety and reliability in case of power failure. The field tests of the water hammer executed at Cheong-Yang booster pump station having an air chamber. The effects were studied by both the practical experiments and the CFD(Computational Fluid Dynamics : Surge 2008). The result states that the system with water hammering protection equipment was much safer when power failure happens. The following data by a computational fluid dynamic analysis are to be shown below, securing the system stability and integrity. (1) With water hammering protection equipment. (1) Change of pressure : Up to $15.5\;kg/cm^2$ in contrary to estimating $16.88\;kg/cm^2$. (2) Change rate of water level : 52~33% in contrary to estimating 55~27%. (3) Note that the operational pressure of pump runs approx. 145 m, lowering 155 m of the regularity head of pump. (4) Note that the cycle of water hammering delays from 80 second to 100 second, together with easing the function of air value at the pneumatic lines. (2) Change of pressure without water hammering protection equipment : Approximate $22.86\;kg/cm^2$. The comprehensive result says that the computational fluid dynamics analysis would match well with the practical field-test. It was able to predict Max. or Min. water hammering time in a piping system. This study aims effectively to alleviate water hammering in a pipe line to be installed with air chamber at the pumping station and results in making the stability of pump system in the end.

• 한국기후변화학회지
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• 제8권3호
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• pp.265-273
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• 2017

Recently the Paris Climate Change Accord has been officially put into effect, making global efforts to implement Greenhouse Gas (GHG) reductions, and also International environmental regulations in the automotive sector will be further strengthened. The electric vehicle, which minimizes the particulate matter generated by existing internal combustion engine automobiles, is evaluated as a representative eco-friendly automobile. However, charging the battery of an electric vehicle is not fully environment-friendly if it is fueled by electricity that is being generated by fossil fuels as an energy source. The energy generated by the photovoltaic power generation system, which is an infinite clean energy, can be used to charge an electric vehicle's battery. Currently, shortage of charging facilities, time of charging, and high battery prices are the problem of activating the supply of electric vehicles. This study is to build a conjunction between the EVBSS (Electric Vehicle Battery Supply System) and ESS (Energy Storage System), which can quickly supply the photovoltaic charged battery to the required demand. If the charged battery in the Battery Swapping Station (BSS) is swapped swiftly, it will dramatically shorten the waiting time for charging the battery. As a result, if the battery is rented when it is needed, electric vehicles can be sold without the cost of a battery, which accounts for a large portion of the total cost, then the supply of electric vehicles are expected to expand. Furthermore, it will be an important alternative to maneuver climate change by minimizing GHG emissions from internal combustion engine vehicles.