• 전기학회논문지
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• 제67권8호
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• pp.994-1001
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• 2018

In this paper, to studied about future power system construction using PSS / E-Python API. Python-based future system automatical construction methods and modeling of renewable sources. it confirmed the stability of the powert system for each renewable area by calculating the weighted short circuit ratio (WSCR) index. it calculated the short circuit ratio (SCR) and selected the transmission line linkage scenario to improve the stability of vulnerable areas. it confirmed the WSCR index improvement through the selected transmission line linkage of scenario, and analyzed the stability of the renewable power system applying the scenario. It describes Facts and Shunt devices adjustment for the load flow convergence. It describes the stable methed of the bus voltage through the transformer Ratio Tap adjustment. By performing PSS/E ASCC using the Python it was performed three-phase short circuit fault capacity analysis, it is confirmed whether excess of the fault current circuit breaker capacity. In order to contingency accident analysis, it have described the generation of one or two line list of each areas using the Python. The list is used to contingency analysis and describe the soluted of the transmission line overload through comparison before and after adding the scenario line.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.220-220
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• 2015

Water, energy, and food security already became a risk that threatens people around the world. Increasing of resources demand, rapid urbanization, decreasing of natural resources and climate change are four major problems inducing resources' scarcity. Indeed, water, energy, and food are interconnected each other thus cannot be analyzed separately. That is, for simple example, energy needs water as source for hydropower plant, water needs energy for distribution, and food needs water and energy for production, which is defined as W-E-F nexus. Due to their complicated linkage, it needs a computer model to simulate and analyze the nexus. Development of a computer simulation model using system dynamics approach makes this linkage possible to be visualized and quantified. System dynamics can be defined as an approach to learn the feedback connections of all elements in a complex system, which mean, every element's interaction is simulated simultaneously. Present W-E-F nexus models do not calculate and simulate the element's interaction simultaneously. Existing models only calculate the amount of water and energy resources that needed to provide food, water, or energy without any interaction from the product to resources. The new proposed model tries to cope these lacks by adding the interactions, climate change effect, and government policy to optimize the best options to maintain the resources sustainability. On this first phase of development, the model is developed only to learn and analyze the interaction between elements based on scenario of fulfilling the increasing of resources demand, due to population growth. The model is developed using the Vensim, well-known system dynamics model software. The results are amount of total water, energy, and food demand and production for a certain time period and it is evaluated to determine the sustainability of resources.

• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.381-387
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• 2012

The planetary exploration rover executes various missions after moving to the target point in an unknown environment in the shortest distance. Such missions include the researches for geological and climatic conditions as well as the existence of water or living creatures. If there is any obstacle on the way, it is detected by such sensors as ultrasonic sensor, infrared light sensor, stereo vision, and laser ranger finder. After the obtained data is transferred to the main controller of the rover, decisions can be made to either overcome or avoid the obstacle on the way based on the operating algorithm of the rover. All the planetary exploration rovers which have been developed until now receive the information of the height or width of the obstacle from such sensors before analyzing it in order to find out whether it is possible to overcome the obstacle or not. If it is decided to be better to overcome the obstacle in terms of the operating safety and the electric consumption of the rover, it is generally made to overcome it. Therefore, for the purpose of carrying out the planetary exploration task, it is necessary to design the proper suspension system of the rover which enables it to safely overcome any obstacle on the way on the surface in any unknown environment. This study focuses on the design of the new double 4-bar linkage type of suspension system applied to the Korea Aerospace Research Institute rover (a tentatively name) that is currently in the process of development by our institute in order to develop the planetary exploration rover which absolutely requires the capacity of overcoming any obstacle. Throughout this study, the negative moment which harms the capacity of the rover for overcoming an obstacle was induced through the dynamical modeling process for the rocker-bogie applied to the Mars exploration rover of the US and the improved version of rocker-bogie as well as the suggested double 4-bar linkage type of suspension system. Also, based on the height of the obstacle, a simulation was carried out for the negative moment of the suspension system before the excellence of the suspension system suggested through the comparison of responding characteristics was proved.

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.397-402
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• 2002

Six Sigma is one of the most active subjects in quality management. This study deals with some existing weaknesses that may arise in implementing Six Sigma in real world situations. The main weaknesses discussed here include the lack of understanding of cultural aspects on the nations and industries, the poor linkage between quality, finance and accounting from the bottom line point of view, and the difficult development process of metrics for all improvement results to validate the effect of Six Sigma. Finally, the key success characteristics for a good Six Sigma project are presented.

• 한국환경과학회지
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• 제7권6호
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• pp.735-744
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• 1998

This research emphasizes the necessity of building a multilateral environmental cooperation. The Process and Problems of multilateral environmental cooperation system are discussed, and some policy proposals are suggested. Especially for Northeast Asia, a comprehensive multilateral environmental cooperation system is required because of transborder pollutions. Within the contractual environment, international institutions can help the parties of conference to build up national capacity to cope with environmental threat.

• 한국관개배수논문집
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• 제9권2호
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• pp.51-58
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• 2002

The purpose of this study is to construct a Water Quality Management System (WQMS) for the Saemangeum watershed based on the linkage of water quality model, i .e. QUALfE, and GIS database to estimate water quality effectively in this area. There are three

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.318-323
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• 2005

This research evaluates agricultural water supply capabilities for water computing demand and supply for water of the whole water system of Ansung stream by carrying out basin water balance classified by irrigation facility of water system of Ansung stream.

• 대한전기학회논문지
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• 제32권11호
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• pp.379-386
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• 1983

In this paper,the more accurate and simple synchronous machine model is derived by parameter modification method. At first, the flux linkage state space model is composed by redefining the parameters of synchronous machine and considering the saturation effect approximately. After that, this modified model is apply to the power system model and the effects of power system stability is analyzed by this model's characteristics in fault condition. As the result, the modified synchronous machine model shows more accurate and simple than the privious one.

• 대한지리학회지
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• 제50권2호
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• pp.203-216
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• 2015

본 연구는 일일 인구이동에 의한 네트워크와 유동패턴을 통해 한국의 도시체계 변화를 고찰하였다. 일일 인구이동이 일상적인 통행패턴을 반영하므로, 도시간 연결관계에 의한 도시체계는 생활권의 관점으로 인식할 수 있다. 2012년 들어 도시간 인구이동이 증가하면서, 도시 네트워크의 연결체계를 비롯하여 출발지와 도착지로 구성되는 통행권의 수가 모두 증가하였다. 통행량의 분산에도 불구하고 서울을 중심으로 하는 수도권과 부산을 중심으로 하는 부산권의 공간범위는 확대되었다. 서울지향형 고속교통망이 구축된 강원도에서는 춘천을 중심으로 하는 소양강문화권과 영동지방의 생활권 분리가 심화되었다. 교통망의 접근성이 양호한 대전과 그 주변지역을 아우르는 생활권은 경기남부까지 확대되었다. 전남에 형성된 기존의 생활권은 광주의 중심성이 약화되면서 목포와 순천을 중심으로 서부와 동부에서 분절되었다. 생활권은 거시적으로 광역 행정경계와 대체로 일치하였지만, 도 경계를 넘어 다른 광역단체의 시군과 통합되는 사례가 증가하였다. 서울과 그 주변 도시간의 상호작용이 강화된 것은 서울을 중심으로 하는 세계도시-지역의 발전 가능성을 높여준다.

• 한국인터넷방송통신학회논문지
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• 제10권3호
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• pp.43-50
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• 2010

무선통신 시스템마다 다르게 적용되는 주파수를 해당 통신 규격에 따라 변환하는 기술인 DDC(Digital Down Converter)는 향후 통신 기술 발달을 위해 필요한 기술로 무선 통신 및 SDR(Software Defined Radio) 시스템에서 필수적인 구성 요소로 인식되고 있다. 또한, 주파수 자원 부족 현상으로 인해 기존 서비스에 간섭을 주지 않고 효율적인 통신 환경을 구성하는 스펙트럼 센싱에 대한 연구가 이루어지고 있다. 본 논문에서는 DDC 시스템을 구성하는 CIC(Cascaded Integrator Comb) 필터, WDF(Wave Digital Filter), SRC(Sample Rate Conversion)의 각 모듈을 세부적으로 분석하였으며, 주파수의 사용 효율을 높이기 위해 DDC 시스템과 스펙트럼 센싱을 효과적으로 연동하는 방안을 제안하고 모의실험에서 검증하였다. 모의실험결과 DDC 시스템의 각 모듈에 스펙트럼 센싱 기능을 적용하여 성능 및 복잡도의 결과를 도출하여 제안한 시스템의 결과를 확인하였다.