• Industrial Engineering and Management Systems
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• 제3권2호
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• pp.129-133
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• 2004

Studies on the optimal location of retail store have been made in case of no obstacle(Minagawa etal. 1999). This paper deals with the location problem of retail store considering obstacles (e.g. rivers, railways, highways, etc.) and obstacle-overcoming points (e.g. bridges, railway crossings, zebra crossings, overpasses, etc.). We assume that (1) commercial goods dealt here are typically convenience goods, (2) the population is granted as potential demand, (3) the apparent demand is a function of the maximum migration length and the distance from the store to customers, (4) the scale of a store is same in every place and (5) there is no competitor. First, we construct the basic model of customers' behavior considering obstacles and obstacle-overcoming points. Analyzing the two dimensional model, the arbitrary force attracting customers is represented as a height of a cone where the retail store is located on the center. Second, we formulate the total demand of customers and determine the optimal location that maximizes the total demand. Finally, the properties of the optimal location are investigated by simulation.

• 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.

• 한국수학사학회지
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• 제31권2호
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• pp.73-91
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• 2018

This study begins with the awareness of problem that the education of mathematics teachers has failed to link the limit and the infinite set conceptually. Thus, this study analyzes the historical and reciprocal development of the limit and the infinite set, and discusses how to improve the education of these concepts and their relation based on the outcome of this analysis. The results of the study confirm that the infinite set is the historical tool of linking the limit and the real numbers. Also, the result shows that the premise of 'the component of the straight line is a point.' had the fundamental role in the construction of the real numbers as an arithmetical continuum and that the moral certainty of this premise would be obtained through a thought experiment using an infinite set. Based on these findings, several proposals have been made regarding the teacher education of awakening someone to the fact that 'the theoretical foundation of the limit is the real numbers, and it is required to introduce an infinite set for dealing with the real numbers.' in this study. In particular, by presenting one method of constructing the real numbers as an arithmetical continuum based on a thought experiment about the component of the straight line, this study opens up the possibility of an education that could get the limit values psychologically connected to the infinite set in overcoming the epistemological obstacle related to the continuum concept.

• 한국철학논집
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• 제56호
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• pp.9-46
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• 2018

국보 제29호인 성덕대왕신종은 신라 중대(中代)의 사상사, 불교사, 정치사, 공예사, 한문학사, 서예사, 금석학사 등 여러 면에서 연구 자료로서의 가치가 높다. 그러나 신종에 대한 일반의 관심도에 비추어 명문(銘文)에 대한 연구는 아직 활발하지 않다. 명문에 대한 판독과 번역의 단계에서 벗어나지 못하고 있다. 체계적인 분석과 연구가 요구되는 시점이다. 이 글은 이런 문제의식에서 기초한다. 부제(副題)를 '사상성의 탐색'으로 한것은 제2차 연구를 염두에 둔 것이다. 본 연구에서는 먼저 종래의 판독과 역주(譯註)를 전면적으로 재검토하였다. 변려문(騈儷文)의 문체적 특성에 대한 연구도 병행하였다. 그 결과 약 20건 정도의 문제점을 발견하였다. 특히 '工匠?模', '日月?暉' 등 중요한 문구에 대한 새로운 해석을 시도한 것은, 명문 해석의 중요성을 부각했다는 점에서 의미가 있다. 신종의 명문은 사상사의 측면에서 연구할 가치가 높다. 명문에는 불교사상, 유교사상, 도가사상은 물론 우리나라 고유사상 등이 서로 걸림이 없이 무르녹아 있다. 전반적으로 철학성이 높은 글이다. '원공(圓空)'을 주제어로 신종의 의미를 부여하면서, 아울러 불교사상의 핵심과 통치철학을 제시한 것이 돋보인다. 한편 성덕왕의 정치이념, 통치원리가 우리 고유의 풍류도(風流道)에 연결되어 있음을 시사한 것은, 풍류도 전승의 맥락을 추적하게 하는 중요한 단서다. 혜공왕 대에 유교사상에 입각한 개혁파와 민족 고유사상에 기반을 둔 보수파와의 대결을 시사한 대목도 함께 보아야 할 대목이다.