• KIEAE Journal
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• 제5권2호
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• pp.19-26
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• 2005

Every site has a different given geometrical and climatic condition, which influenced not only the lifestyle of the humanbeings but also the regional architecture. For example, on a cold region, the reduction of the energy loss is necessary, like an igloo, which has a littlest energy loss at hemisphere. Or on a warm region, the house must be protected thermally from the overheating at the sunshining. like a huge shading. An architectural interpretation in the (extreme) moderate climate, like Korea, has always tried to satisfy the both opposite demands simultaneously. A facade, which divides out- and inside, has an ideal position to lead the regulated regional climatic conditions into the room. The Double Facade System(DFS) is well known as an innovative solution in the european countries, like Germany. It provides an reasonable alternative, which can achieve these goals at the same time. A Double Facade System provides an effective sunshade, which means a cooling energy reduction at the warm season. In addition, it enables a natural ventilation at the cold season with the preheating at the system as well as spring and autumn. An ordinary Single Facade System with a inside or outside sun blind provides a solution just for a specified season, like a summer or winter. But the Double Facade System can deal with the various climatic conditions in the moderate climate.

• KIEAE Journal
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• 제14권6호
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• pp.53-58
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• 2014

Residental photovoltaic power system achieved remarkable results in distribution and activation through 'One Million Green Homes Program' led by the government. However, system maintenance and management after installation are relative unsatisfactory. Thus, problems, such as malfunctioning, decrease in efficiency, breakage, etc, are occurring in succession which means that expensive facilities are not used effectively. This study attempted to propose a more preferred alternative to the photovoltaic power system currently applied and installed to the housing by investigating and analyzing the said system, identifying management practices, and deriving problems. For this study, 48 houses equipped with photovoltaic systems in J City were chosen and they were analyzed after preliminary research and field investigation. The results revealed that most of the surveyed systems in J City are still in fairly good conditions. But the instruction and information regarding the appropriate operational management of those surveyed systems have not been delivered to the owner. Therefore, promotion education and related manual deployment should be done by the contractor. In terms of installation, inadequate system location and some warranty services are required to be improved, which are usually caused by a lack of careful planning and construction. In addition, the follow-up management needs to be provided about five years later after installation considering system deterioration.

• 한국인터넷방송통신학회논문지
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• 제14권6호
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• pp.163-167
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• 2014

한국승강기안전관리원 사고현황 분석 자료에 따르면 안전사고 요인으로 이용자의 과실 부주의가 60%를 차지하여 안전한 엘리베이터 사용을 위한 수시 모니터링이 가능한 스마트 관리시스템의 필요성이 대두되는 시점이다. 이에 본 논문은 현재 엘리베이터 안전점검의 기준 및 사고 발생율을 살펴보고 기존 엘리베이터 관리시스템 구조와 자체 결함 감지 및 알림기능의 IOT기반 스마트 관리시스템 구조의 차이를 확인한다. 또한 엘리베이터 전문가 집단의 의사결정을 통해 IOT 기반 스마트 관리시스템을 도입할 경우 기대되는 관리 효과에 대해 신뢰성 검증을 한 뒤 기존 엘리베이터 안전사고의 주된 요인인 이용자의 과실 부주의에 대한 구체적 대안으로 제안한다.

• Strategy21
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• 통권41호
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• pp.208-231
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• 2017

The balance of power in conventional forces between the two Koreas works in favor of the South Korea in the Korea peninsula. But, the balancing mechanism between the two Koreas in asymmetric forces like nuclear and missile forces works absolutely in favor of the North Korea. That's why it should be timely for the ROK military to review existing strategy and revise a new counter strategy against the threat posed by the North Korea's nuclear and missile forces. The ROK military is now developing 4D, KAMD, KILL Chain strategies as means to cope with the North Korea's nuclear and missile threats. Considering efforts and resources invested now, the strategies are expected to be in place in next five or more years. However, approaches to those strategies seem to be rather fragmentary and conceptual than comprehensive and pragmatic. The types of strategies against the North Korea's military threats need to be a deterrence in peace time and a fighting and winning in war time in the Korean theater. But, the most important element in the deterrence strategy is the credibility. This study concludes with an new strategic concept titled "ADAD(Assured Defense, Assured Destruction)" as an alternative to existing strategies to deal with the North Korea's nuclear and missile threats.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.143-146
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• 1999

A method to control the speed of DC motor with one-chip microprocessor PIC using PWM is discussed in this paper. This thesis deals with the DC motor speed control for electric bicycles which may be used as an alternative means of transformation in the future. We tried to design a stable system for controlling the speed of DC motor and materialized an electric bicycle loading this system. Now we are on the way to find out the problems this system has and work out the solutions.

• 한국세라믹학회지
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• 제47권6호
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• pp.618-622
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• 2010

Cost-effective purification methods of silicon were carried out in order to replace the conventional Siemens method for solar grade silicon. Firstly, acid leaching which is a hydrometallurgical process was preceded with grinded silicon powders of metallurgical grade (~99% purity) to remove metallic impurities. Then, plasma treatments were performed with the leached silicon powders of 99.94% purity by argon plasma at 30 kW power under atmospheric pressure. Plasma treatment was specifically efficient for removing Zr, Y, and P but not for Al and B. Another purification step by EB treatment was also studied for the 99.92% silicon lump which resulted in the fast removal of boron and aluminum. That means the two methods are effective alternative tools for removing the doping elements like boron and phosphor.

• Smart Structures and Systems
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• 제10권2호
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• pp.89-110
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• 2012

This study was intended to efficiently perform the probabilistic optimal safety assessment of steel cable-stayed bridges (SCS bridges) using stochastic finite element analysis (SFEA) and expected life-cycle cost (LCC) concept. To that end, advanced probabilistic finite element algorithm (APFEA) which enables to execute the static and dynamic SFEA considering aleatory uncertainties contained in random variable was developed. APFEA is the useful analytical means enabling to conduct the reliability assessment (RA) in a systematic way by considering the result of SFEA based on linearity and nonlinearity of before or after introducing initial tensile force. The appropriateness of APFEA was verified in such a way of comparing the result of SFEA and that of Monte Carlo Simulation (MCS). The probabilistic method was set taking into account of analytical parameters. The dynamic response characteristic by probabilistic method was evaluated using ASFEA, and RA was carried out using analysis results, thereby quantitatively calculating the probabilistic safety. The optimal design was determined based on the expected LCC according to the results of SFEA and RA of alternative designs. Moreover, given the potential epistemic uncertainty contained in safety index, failure probability and minimum LCC, the sensitivity analysis was conducted and as a result, a critical distribution phase was illustrated using a cumulative-percentile.

• 한국유기농업학회지
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• 제23권4호
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• pp.923-938
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• 2015

This study was conducted to serve as the basis for establishing a standard cultivation, which enhances the alternative utilization of pig manure, a major cause of environmental pollution, by finding a means for reducing greenhouse gas emissions for eco-friendly cultivation. In a laboratory, $CH_4$ and $CO_2$ emission patterns were investigated corresponding to incremental pig manure treatments in paddy soil. The emissions peaked 12 to 27 days after manure application in the 100~400% applications. It was found that increasing applications of pig manure resulted an increase in $CH_4$ and $CO_2$ emissions. Additionally, application of more than 150% emitted a larger amount of these gasses than applying chemical fertilizer. However, the test application of 100% pig manure emitted a smaller amount of $CH_4$ and hence Global Warming Potential (GWP) than those emitted by chemical fertilizer. If appropriate amount of fertilization is applied in compliance with the standard application rate, the pig manure may be effective in reducing greenhouse gas emissions and the soil environment made more favorable than with the use of chemical fertilizer.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.390-398
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• 1999

The thermomechanical control process(in hot rolling strip mill) was employed to produce 2.25Cr-1Mo steel, which is to be construction material for the steam generator for power plant. Although the Conventional processes has been the primary means of producing the 2.25Cr-1Mo steel, an alternative method was used to meet the specification of ASTM heat treatment for A387-22-Classl using autotempering after coiling in hot rolling strip mill. The microstructures, tensile properties at various temperatures, and creep-rupture properties have been investigated to compare the properties with those of materials produced by the conventional process and to certify the application of the thermomechanical control process to an actual process of manufacturing 2.25-Cr-1Mo steel, this in turn, will reduce the cost of the process. About 14 to 34% glanular bainite (remainder proetectoid ferrite) formed in a coil, and this variety of volume fraction stems from the different cooling rates, which varies with position of the coil after coiling. Tensile testing from room temperature to 700$^{\circ}C$ indicated that strength increases with test temperature showing peaks at around 600$^{\circ}C$. Creep-rupture properties have been being investigated at the temperature of 500$^{\circ}C$ with 27.5, 32kg/$\textrm{mm}^2$ loads and have showed no rupture for over 1000 hours.

• 상하수도학회지
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• 제22권4호
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• pp.449-454
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• 2008

Some pretreatment methods have been proposed to enhance the biodegradability and to shorten the hydrolysis reaction time. By means of efficient pretreatment the suspended solids (SS) can be made of better accessible for the anaerobic bacteria. There are several ways how this can be accomplished, which include biological, mechanical, thermal, and chemical methods. For the sludge solubilization using the cavitation phenomenon, we have tried to develop a pretreatment process consisted of a reactor and pumps. The objectives of this study were to develop a advanced wastewater treatment consisted of IABR and the cavitation with PGA. The most effective removal for organic matter and nutrients were occured when both cavitation pretreatment and ${\gamma}$-PGA were applied at the IABR process. Only small portion of ${\gamma}$-PGA at a rate of 1.38mg/L, was enough to improve sedimentation ability, SS removal efficiencies, and sludge volume reduction. After the sludge solubilization by the cavitation, SCOD increased to 193% and SS decreased to 36%. The removal ratio of BOD was 94.5%, T-N removal ratio was 85.5% and T-P removal ratio was 84.9%. The combination process of the IABR with the cavitation and PGA addition seems to be very effective alternative wastewater treatment process.