• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.43-46
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• 2017

Recently, the development of underground space is being actively carried out in the urban area by saturation, and the excavation works are mainly carried out by various excavation methods by the structures adjacent to the ground and underground excavation. During such excavation work, ground subsidence accidents are occurring due to inattention construction, lack of construction technology, and leakage of ground water. For the prevention of ground subsidence we studied the method of risk influence factors by soil investigation. Analysis of 75 sites soil investigation by U.S.C.S (Unified Soil Classification System), construction method, depth of excavation and we studied the risk influence factors with ground subsidence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.2
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• pp.217-224
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• 2002

One of the dominant aspects governing the accuracy of the FDTD method is the size of the spatial increment used in the model. The effect of having reduced cell size is to increase the computational time and memory requirements. To overcome these problems, sub-gridding technique can be used. This implies that the application of a sub-grid cell would provide improved accuracy without increasing the run time and computer resources considerably. In this paper, we describe the three dimensional sub-gridding technique that is applied to model only the fine structure region of interest. The detailed solution procedure is described and some test geometries were solved by both uniform grid and sub-grid models to validate the suggested approach. While keeping the accuracy, the computational time becomes 6 times faster and the memory requirement is reduced by a factor of 2.5 comparing to the conventional FDTD approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.464-469
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• 2019

Tapered roller bearings are used widely in vans, trucks, and trains because they can support the vehicle in a stable manner even under a heavy load. The cage of a tapered roller bearing maintains the gap between the rollers, which prevents friction wear and suppresses heating. If the cage is severely deformed due to resonance, the roller may not be able to roll smoothly and even leave the cage. Consequently, it is very important to analyze the dynamic characteristics of the cage for reliable performance of a bearing. The cage essentially has geometrical tolerance in the manufacturing process. In this paper, the effects of those geometrical imperfections on the dynamic characteristics of the cage were investigated. As a result, natural frequency separation occurred near the natural frequency of the ideal cage due to geometrical imperfections. In addition, the interval was proportional to the magnitude of the geometric error, and the interval increased with increasing mode number.

• The Science & Technology
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• v.10 no.9 s.100
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• pp.33-39
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• 1977

토목기술이란 토목사업을 지탱하는 기술로서 여기서 토목기술이란 토목을 주로 하여 건축구조의 공학적인 것을 포함한 기술이라고 할 수 있다. 토목사업은 오늘날 국토의 보전ㆍ수자원개발ㆍ교통로정비(항만포함)ㆍ도시와 지방계획 및 상하수도를 포함한 도시건설 등이며, 어느 것이나 국민의 생산과 생활환경개선 등 우리 인간의 앙적한 생활과 복지편익을 추진시키는 기간산업이 아닌 것이 없다. 그래서, 인간사회가 발전을 갈망한다면 토목건설사업이 선행되어야하고, 토목사업으로 확립된 기반아래 국민들의 건전한 생활이 영위되는 것은 물론이다. 토목이라하면 주로 우리나라에서는 국토건설로서 지역, 또는 국가사회의 경제발전에 크게 영향을 미치는 토목건설사업을 말한다. 이것은 토목기술의 발전이 그때 그때의 건설사업으로서 구상화되는 까닭이라 하겠다. 한편, 인간의 가치관에 변화가 생기고 자원문제ㆍ공공문제ㆍ생활환경문제 등이 크게 변화하는 단계에 있어서도 그 방향을 탐색하고 우리 인간 및 국가사회가 의도하는 건설공간구상을 계획하고 사업화 하는데 매우 중요한 것은 토목건설인 까닭에서이다. 이런 의미에서 최근 100년간의 경이적인 서구의 근대화 과정에서의 토목기술 발전, 즉 이 기술이 매우 오늘날 세계를 변혁시킨 사실에서 출발한데 대비하여 우리 나라 개항 100년 이후의 안타까운 우리의 기술수용과정을 볼 때 1986년 강화도조약 이후 한반도는 일본 및 청국을 위시한 구미열강외세의 각축장으로서 혼미된 서구근대기술의 도입요람기로 시작하여 1810년 한일합방에서 8.15해방까지 일본통치하에서 타율적인 토목ㆍ건축기술의 도입으로 한마디로 말해서, 거의 70년간의 진통기가 있음을 엿볼 수 있다. 하지만 최근 30년 사이에 그야말로 우리 토목기술터전은 급격하게 성장 발전하고 있다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.403-410
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• 2009

This paper discusses an application method of critical strains concept for tunnels' safety by using the values of measured displacements which are obtained in the field. The aim of this paper is to: (1) study on the engineering meanings of critical strains concept by reviewing the previous researches and application examples with measured displacement values; (2) study on the engineering reasonability of critical strains concept with the view point of a tunnel engineering and a geotechnical engineering; (3) study on the features of ground deformation due to tunneling and reciprocal relation between total displacement and measured displacement; (4) evaluate a tunnel safety by using domestic measurements collected in the field; and (5) re-evaluate the control criteria which were previously used in the field, with the view point of critical strains concept. Consequently, it was confirmed that critical strains in the ground has a reasonability and a possibility of unified or common concept with the view point of a tunnel engineering.

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.1
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• pp.39-67
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• 1987

The purpose of this thesis is to suggest objective basic data for the environmental design through the quantitative analysis of the visual quality included in the physical environment of forest landscape. For this, landscape values of forest landscape have been evaluated by using the Iverson method, the images structure of forest landscape's main utilizing space have been analysed by the factor analysis algorithm, degree of visual preferences have been pleasured mainly by questionnaries and SBE method, and finally these thesis can be summarized as fallow LCP with high values of Iverson factors I and IV yield high landscape value. Specifically, Iverson factor IV has been found to play the dominant. For all experimental points, significant seasonal variations in S.D. scale values have been observed. In natural parks, where artificial structures are complementary to the natural landscape, main factors of image are S.D. scales such as the visual sequence, the formal simplicity of structures, the emphasis, the unification of heterogeneous factors and the assimilation. Factors covering the spatial image of natural parks have been found to be the overall evaluation, the individual characteristics, the tidiness, the potentiality, the dignity, the intimacy and the space volume. For all seasons, factors such as the individual characteristics, the dignity, the tidiness, the potentiality, yield high factor scores. As for factors determining the degree of visual preference, variables such as the summit, the skyline, rocks, the water and the degree of natural destruction by artificial structures yield high values for all seasons.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.374-382
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• 2020

Purpose: Recently, structural defects in old safety management facilities have led to the collapse of buildings and facilities. The purpose of this study is to develop guidelines for the installation of regular monitoring systems that determine the optimal sensor location for monitoring exhibition space building sensors equipped with visual elements in order to analyze the risk signs of exhibition space buildings and develop measurement technology. Method: The components, installation locations, alarm criteria, and management measures of the instrument are presented. Result: A measure was proposed to determine the location of sensors, secure signal processing technology for analysis by having unified visual perception, and configure optimal 'risk sign detection' based on sensor monitoring through test-bed operation. Conclusion: The results of this study can be prepared against the disasters that may arise from the collapse of exhibition buildings, and contribute to strengthening safety management capabilities.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.229-235
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• 2018

The Hanok church is an important cultural heritage that can be considered from a religious point of view of life in the modern age in Korea. We will investigate the bounadaries of the Hanok church built in modern age and the characteristics of Hanok architectural. To do so, we have conducted field trips, interviews, and repair reports of the Gimje Geumsan Church in the Jeollabuk province. The Geumsan Church is present, and the architectural characteristics can be confirmed in detail. In addition, Yugwang School, which was responsible for the education function, was able to guess the location and size through the data. As a result, the boundaries of Geumsan Church is the present fence, the west side has the building, and the east side has the playground. The Geumsan Church's flat form was divided into male and female according to the space configuration of ㄱ-shaped reflecting Confucian thought of the time. And it seems that the Yugwang school was located in the entrance part of the modern church with a two-frame scale, which is suitable for lecture.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.295-308
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• 1996

1. Retrospect of Political Geographic Studies since Liberation, 1945 : 1) Period from 1945 to mid 1960s : There was not political geography as a science in Korea at the time of liberation from Japan 1945. At that time were not pure political geographers in Korea. In 1947, Moon-Hwa Pyo, economics professor, published a book titled Outline of Korean Geopolitics. This book was a first one in the field of political geography and available at that time in the logical descriptions. Bok-Hyon Choi was a first political geographer who in 1959 wrote a book titled Political geography for the collegians of Seoul National University. Professor Choi introduced American-style political geography through the book above mentioned. In 1963, Kie-Joo Hyong published an article titled "Korean Unification: Possibility from the Geopolitical Viewpoint" which was a first article published by Korean young scholar who studied geography in this country. 2) Period from late 1960s to late 1980s : Both Yoon Cha and Duck-Soon Im published frequently several articles of political geography or geopolitics respectively in 1968-1969. And they issued geopolitical disputes on Korean geopolitical structure and an application of rimland theory to Korean peninsula in 1969 through a magazine named Joung-Kyong Younku (the political and economic researches). The disputes played an important role of showing political geography (or geopolitics) to political sciences especially international political Science. Active researches still continued in 1970s. In that atmosphere the first Korean book of political geography written by a post-liberation scholar (Duck-Soon Im) titled Principles of Political Geography was published in 1973. This book was influenced much by American political geography after Second World War. In 1980s, the researches continued more actively. Especially administrative districts, capital cities, and sub-capital cities were frequently studied during this period. 3) Period from late 1980s to Present: Recent Studies : 1985 was a year of much production of articles of political geography. The first Ph.D thesis of political geography published in the same year in our country. And since 1985 produced many M.A. articles. Several categories of esearches of political geography was made in the period from late 1980s to present. Capital cities, Korean unification, administrative districts, urban politics, elections, sub-capital cities, and defense walls were important research categories. Reviewing the researches from 1945 to present. I found eight categories of political geography in Korea: capital cities, administrative districts, geopolitical structure of Korean peninsula, division and unification of Korea, sub-capital cities, defense walls, elections, and urban politics. Each category includes several scholars respectiveiy. 2. Study Tasks and Prospects in Korean Political Geography: In relation to Korean circumstances there are three study-tasks. The first task of Korean people is unification of two Koreas. Political geographers of Korea must al survey titled Survey Methods of Human Geography for collegians. This book was first one on survey part in Korea. The book however, is insufficient in comprehensiveness in aspects too. I think that the important tasks of general-synoptic human geography in Korea are \circled1 publication of comprehensive books of human geography in the aspects and methodologies for collegians and \circled2 acceptance of academic world of human geography in Korea of variety in methodologies of human geography for future progress. progress.

• Journal of Korean Society of Forest Science
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• v.80 no.1
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• pp.32-41
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• 1991

This study is focusted to the national park of Korean typical mountain Chi-ri, its visual resources of forests, and practiced inspectind course by way of hypothesis and tests, to show visual resource management objectively, and that of quantitative basic data. spatial image structure measured by Semantic Differential(S.D.) Scale was shown through factor analysis algorithm for the analyzing psychological amount and examined the flowing out of decisive factor and the objective importance related mutual factors by appling the measurement of visual quality. Also, it has been investigated the differences between the degrees of expectation which is used before and of satisfaction which is used, by appling instrumental expectation theory. And showed patterns of investigation area through factor analyzing algorithm. As a national Park, visual factors that have natural landscape harmonized forest, sky, surface of the water, curious stones and rocks, temples should be escalate their values affirmatively so as to be the scenery of pointed direction and enjoyable, and it is needs the techniques visual resource management and its controlling technique to make artificial structures more intentional planning and systemical setting. Manmade distinctive quality in the spatials that affect complementally or harmonizingly, should be received considering relations between the distifution and joining which in line with various visual presenting massive factors. More than that, it is needed united basic standard to the beauty of arrangements which contain visual continuity considered balance between nature and human work, simplicity of structural types, assimilation, emphasis, unification of different factors and pro rata.