• Industrial Engineering and Management Systems
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• v.3 no.2
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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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• v.29 no.4
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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.

• Journal for History of Mathematics
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• v.31 no.2
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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.

• The Journal of Korean Philosophical History
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• no.56
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• pp.9-46
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• 2018

Seongdeokdaewang-Shinjong, the 29th National Treasure, is highly valuable as a study material in various aspects including the histories of ideology, Buddhism, politics, art-craft, Chinese character study, calligraphy, epigraphy and so on of the mid-time of Shinra. Compared with the people's interest in the Shinjong, however, the studies on the words carved on it have not been yet deepened. Such studies have not been yet overcoming the phase of decoding and translation of the words. Today, it is required to analyze and study the words systematically. This article starts with such critical mind. That is why the subtitle of this article is Research on the Background of Thoughts considering that this study must be followed by its 2nd study. This study has totally reviewed the decoding and annotation works that have been done so far. Byeonryeomun (騈儷文: a writing style of Chinese character) has been also studied on its written patterns. As a result, approximately 20 problems have been found and corrected. Especially, such key phrases as '工匠?模' and '日月?暉' have been translated in a new way to spotlight the importance of translation of the carved words. The words carved on the Shinjong are highly valuable to study in the aspect of ideology history. The words fully show not only Buddhist thoughts, Confucian thoughts and Taoist thoughts but also Korea's own unique thoughts, which are all melted in the words without any obstacle to each other. In general, they are highly philosophical words. The words are unique especially in the aspect: They give a meaning to the Shinjong based on the keyword Won-Gong (圓空: circle and empty) and suggest the key point of Buddhist thoughts and governing philosophy altogether. That is, they imply that King Seongdeok's political ideology and governing principle are connected to Pungryudo (風流道), Korea's own unique philosophy. This implication is key evidence that makes it possible to trace the context of transmission of Pungryudo. You should not miss also the phrases implying that there was a big argument between reform group based on Confucian thoughts and conservative group based on Korea's own unique thoughts.