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퍼지논리를 이용한 수평 머시닝 센터의 열변형 오차 모델링
이재하,이진현,양승한,Lee, Jae-Ha,Lee, Jin-Hyeon,Yang, Seung-Han 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.10
As current manufacturing processes require high spindle speed and precise machining, increasing accuracy by reducing volumetric errors of the machine itself, particularly thermal errors, is very important. Thermal errors can be estimated by many empirical models, for example, an FEM model, a neural network model, a linear regression model, an engineering judgment model, etc. This paper discusses to make a modeling of thermal errors efficiently through backward elimination and fuzzy logic strategy. The model of a thermal error using fuzzy logic strategy overcomes limitation of accuracy in the linear regression model or the engineering judgment model. It shows that the fuzzy model has more better performance than linear regression model, though it has less number of thermal variables than the other. The fuzzy model does not need to have complex procedure such like multi-regression and to know the characteristics of the plant, and the parameters of the model can be mathematically calculated. Also, the fuzzy model can be applied to any machine, but it delivers greater accuracy and robustness.
이재하(Lee Jae Ha) 한국지역개발학회 1994 韓國地域開發學會誌 Vol.6 No.2
The central government of Korea in 1994 promotes the consolidation of city(Shi) and county(Gun) which are separate local administrative district. The consolidation of such administrative district has a profound effect upon daily life of residents, equity of administration, regional balanced development, and conservation of natural environment in a administrative region. From this point of view, this paper examines the consolidation of city and county from the perspective of related urban and regional development theories such as growth center, agropolitan development, optimal size of city as well as urban and regional sustainable development, and discusses its reasonable alternative. It is evaluated that the simple consolidation of city and county without consideration of size and function of each administrative district has a negative effect upon equity of administration, regional balanced development and conservation of natural environment. As an alternative, it is suggested that the desirable consolidation of city and county should be accomplished between cities of less than population 200,000 and counties of less than 100,000.
이재하(Jae Ha Lee),이혜주(Hae Joo Lee) 한국지역지리학회 1999 한국지역지리학회지 Vol.5 No.1
본 연구는 최근에 지리학에서 새로운 지역연구 방법론으로 등장하고 있는 세계체제론적 지역지리학에 의하여 특정한 지방(locality)인 구미지역을 사례로 경험적인 지역연구를 시도하였다. 이를 위해 본 연구에서는 자본주의 세계체제에 편입된 한국자본주의의 발달시기를 일제식민기, 해방후 혼란기, 경제발전기 등으로 구분하고, 각 시기에 따른 구미지역의 경제적 특성과 공간구조적 특성에 대한 분석을 통해 그 지역성 변화를 밝히려고 하였다. 구미지역도 일제식민기와 해방 후 혼란기에는 한국사회와 마찬가지로 세계경제의 주변지대에 속하면서 농업을 주된 산업으로 하고 있었다. 이에 따라 이 시기에는 지역의 공간구조도 도시가 형성되지 않은 농업사회적 구조를 이루고 있었다. 그러나 경제개발기에 들어와서는 구미지역도 한국의 산업화정책에 포함됨으로서 산업지역(구미공단 조성)으로 변모돼 세계경제의 반주변지대로 발전한다. 이와 함께 공간구조도 산업이 입지한 지역(도시)과 그렇지 않은 지역(농촌)간의 불균등발전이 심화된 중심-주변의 공간구조로 변화되었다. 세계체제론적 지역지리학은 특정 지방(소지역)의 지역성 변화를 거시적인 세계적 맥락(세계자본 주의)에서 경제적(산업적) 특성 뿐만 아니라 공간구조적 특성도 설명할 수 있다. 따라서 세계체제론적 지역지리학은 지역연구에 유용한 지리학적 방법론으로서 활용될 수 있을 것이다. This paper aims to understand the changing characteristics of the Kumi region as a locality in Korea through the regional geography of the world-system approach. To illustrate the changing regional characteristics, we analyzed the economic characteristics or position of the Kumi region within the world-economy and its spatial structure with three divisions of Korean capitalist periods: the Japanese colonial period (1910∼1945), the social chaos period (1945∼1960), and the economic development period (1960∼present). In the Japanese colonial and social chaos periods, as Korean society was incorporated into the peripheral zone within the world-system (world-economy), Kumi also was made into a peripheral agricultural area. As a result, the Kumi region shaped the rural spatial structure without an urban center or regional dominant center. In the development period, influenced by the manufacturing-centered economic policy which boosted Korea as a semi-periphery within world-economy, Kumi also was developed into an industrial region(or semi-periphery) with the establishment of the Kumi electronic and textile industrial complex. This industrialization transformed the rural spatial structure of Kumi into a core (urban center)-periphery (rural area) structure. As we identified above, the regional geography of the world-system approach turned out to be a useful methodology to study a locality or internal region. Therefore we should make efforts to study such regions through the regional geography of the world-system approach.