• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.263-268
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• 1997

Development of a high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of tool change time as well as repid travel time can enhance the productivity. However,the high speed feed drive system generates more heat in nature,which leads to thermal expansion that has adverse effects on the accuracy of machined part. The paper divides the feed drive system into the ball screw and guide way. For each part, the thermal behvior model is separtately developed to estimate the position error of the respective feed drive system that is caused by the thermal expansion. The modified lumped capacitance method is used to analyze the linear position error of the ball screw. The thermal deformation of guide way parts affects the straightness and angular error as well as linear position error. Finite element method is used to estimate the thermal behavior of these guide way parts. The effectiveness of the proposed models are verified through the experiments using laser interferometer.

• 대한기계학회논문집B
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• 제26권5호
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• pp.716-723
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• 2002

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model (TRM) was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than 7$^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air and -water flow rate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.96-101
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• 2001

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than $7^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air flow rate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.393-398
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• 2001

Pulsations, vibration and stress are the basic dynamic phenomena in power plant piping systems which directly affect system reliability. These phenomena are both acoustical and mechanical in nature and are closely interrelated. It was noticed that thermodynamic parameters were changed after replacing with new type tube bundles of reheat exchanger. It was reported later that the drain piping connecting the new bundle header with the associated drain tank is regularly pulsating at about every 3 second with 13.4㎐ and 7.5mm, p-p in amplitude. This amplitude is about 6 times higher than reference level of sound piping. The results of finite element analysis of the pipeline showed that its dominant natural frequency is 13.4㎐. The soundness is predicted whether the bending dynamic stress evaluated excesses the maximum allowable high cycle fatigue stress or not by the measured amplitude of vibration.

• 한국가구학회지
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• 제19권5호
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• pp.387-402
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• 2008

Today's restaurant is the space not just for eating, but enjoying the mood, communication space for social life, and leading trend. Therefore interior design is concerned with one of the most important role for creating unique atmosphere of restaurants. This study is aimed to analyze how to interior design elements affect the improvement of New York hip restaurant reputation, focusing on the importance of the establishment of unique trend. Through the case studies of New York hip restaurants, it is suggested that interior design is composed to not only significant different element, but also common design concept. It is mainly divided by 5 categories which is the Fusion mixed with eastern culture throughout the vision of the western, the New Baroque redefined tradition and modern thought, the Modern Classic created by importance of concise style and beauty of material, the High Concept used with new materials and technologies, and the Naturalism focused on spirit from nature and eco. Recently New York hip restaurant through the corporation work with star chef and star designer is developed to provide the enjoyable and anticipated spaces with strong theme and entertainments.

• 대한수학회지
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• 제33권1호
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• pp.25-29
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• 1996

The Debreu-Gale-Nikaido theorem [2] is a potential tool to prove the existence of a market equilibrium price. Walras' law is of a quantitative nature (i.e. it measures the value of the total excess demand), and it is interesting to note that the existence result holds true under some qualitative assumptions. In fact, the Debreu-Gale-Nikaido theorem states that the continuity of the excess demand function and Walras' law has the following implication : For some price and corresponding value of the excess demand function, it is not possible to respond with a new price system such that the value at the new price of every element in the value of the demand function associated with the old price system is strictly positive.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.698-703
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• 2000

In a computational fluid dynamics, the imposition of open boundary condition has an important part of the accuracy but it is not easy to find the optimal boundary rendition. This difficult is introduced by making artificial boundary in unbounded domairs. Such open boundary requires us to ensure the continuity of all primitive variables because the nature is in continuum. Here we introduce a revised well-conditioned open boundary condition particularly in FEM and apply it to various problems-entrainment, body force, short domains.

• 소성∙가공
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• 제18권6호
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• pp.444-447
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• 2009

Piston crown to the hot forge a unified nature of the product has a shape with multi-level step forging process, so if you are not a mechanical professional, this process could lead to a significant loss to the material. Therefore, material technology in minor terms; continue to improve the collection rate that undamaged the product material. The piston crown and the manufacturing products such as marine diesel engines are being forged to reduce costs and to improve mechanical properties. Piston crown molding is a hot forging process that works in large volume forging products. Because of the size of the hard plastic material flow process for improving the design and actual field experience through advanced plastic technology, it is important to interpret the results. Also for many experimental plastic procedures, the accumulation of results is very important.

• 한국가구학회지
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• 제13권1호
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• pp.85-95
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• 2002

Environmental furniture comprises an independent design branch as distinguished from he design of street furniture. Environmental furniture helps people enjoy outdoor relaxation and cultural activities by creating convenient facilities and plays a part as the medium connecting environment and living. As a tool effecting all outdoor living conditions including home and public environment, it helps people lead a convenient and safe outdoor life. It is an important element that contributes to the image of outdoor scenery. Therefore, the design of environmental furniture should : 1)consider environment including 3R(Recycle, Reuse and Reduce) which makes harmony with nature without destroying it. 2)seek qualitative improvement by using environmental friendly materials and continuously developing new materials. 3)be assisted by the administrative support from the government to make the environmental furniture design an integral part of the city plan. The quality of a city environment will be greatly improved when people's interest in and their changed view towards environmental furniture is effected.

• 한국컴퓨터정보학회논문지
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• 제11권5호
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• pp.321-327
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• 2006

최근 들어 상업적이거나 과학적인 데이터들의 폭발적인 증가를 볼 수 있다. 이런 데이터들은 항목들 간의 순서적인 면을 가지고 있는 시퀀스 데이터들이다. 그러나 항목들 간의 순서적인 면을 고려한 클러스터링 연구는 많지 않다. 본 논문에서는 이들 시퀀스 데이터들 간의 유사도를 계산하는 방법과 클러스터링 방법을 연구한다. 특히 다양한 조건을 고려한 확장된 유사도 계산 방법을 제안한다. splice 데이터 셋을 이용하여 본 논문에서 제안하는 클러스터링 방법이 기존 방법 보다 우수하다는 것을 보여준다.