• 품질경영학회지
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• 제32권3호
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• pp.126-140
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• 2004

The AS 9100 aerospace standard has become the aerospace quality management system standard agreed to, instead of ISO 9001 and MIL-Q-9858A by international aerospace manufacturing companies. In this paper correlative requirements of each of the standards are compared and analyzed. Then the evolutionary concept and its direction is proposed as a guide to participate in the preparation and establishment of current aerospace quality management systems. This study is applicable to the future as well as present aerospace manufacturing activities throughout the world.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.266-272
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• 2002

High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and hugh fried rate, high-speed machining can alive great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is discussed fur the results of surface roughness and machining error in Z-direction of the high speed machining.

• Asia pacific journal of information systems
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• 제10권3호
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• pp.17-40
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• 2000

This study aims at proposing a direction of improving the efficiency in Korean information technology(IT) industry. In the face of re-engineering which has been done in most industries, it is very important to assess the validity of their restructuring or M&A based on the future efficiency. At first, by using the DEA/WINDOW, we will evaluate how the 30 firms are efficient for outputting their performance with respect to the profit realization and market ability. Then, in order to propose the direction of the efficiency improvement and suitable restructuring strategy, we will clarify how the efficiency of IT firms depends on their firm size. Finally, we will analyze their 'economy of scale' and also reveal how their economy of scale depends on the firm size based on return-to-scale(RTS).

• Journal of applied mathematics & informatics
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• 제8권2호
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• pp.417-428
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• 2001

Spatial distribution of groundwater contaminant concentration has special characteristics such as approximate symmetric profile, for example, in the transversal direction to groundwater flow direction, a certain ratio in directional propagation distances, etc. To obtain a geophysically appropriate semivariogram which is a key factor in estimation of groundwater contaminant concentration at desired locations, these special characteristics should be considered. Specifically, the concepts of symmetry and ratio are considered in this paper. By applying these two concepts, significant improvement of semivariograms, estimation variances, and final estimation results compared with the ones by conventional approaches which usually do not account for symmetry and ratio are shown using field experimental data.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.9-16
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• 1993

For efficient storage and transmission of medical images, the requirement of image com pression is increasing. Because differences between reconstructed images and original images are related with errors In the diagnosis, lossless compression is generally preferred in mod- ical images. in Run Length Coding which is one of the lossless compression method, we have applied modified scanning direction based on the Hilbert curve, which is a kind of space fill ins curve. We have substituted the traditional raster scanning by Hilbert curve direction scanning. Using this method, we have studied enhancement of compression efficiency for medical images.

• Structural Engineering and Mechanics
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• 제37권5호
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• pp.529-542
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• 2011

Three dimensional solutions for free vibrations analysis of functionally graded fiber reinforced cylindrical panel are presented, using differential quadrature method (DQM). The orthotropic panel is simply supported at the edges and is assumed to have an arbitrary variation of reinforcement volume fraction in the radial direction. Suitable displacement functions that identically satisfy the simply supported boundary condition are used to reduce the equilibrium equations to a set of coupled ordinary differential equations with variable coefficients, which can be solved by differential quadrature method to obtain natural frequencies. The main contribution of this work is presenting useful results for continuous grading of fiber reinforcement in the thickness direction of a cylindrical panel and comparison with similar discrete laminate composite ones. Results indicate that significant improvement is found in natural frequency of a functionally graded fiber reinforced composite panel due to the reduction in spatial mismatch of material properties.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.203-209
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• 2003

The study on the user-centered interior design of trains consists of the practice of sensitive technology for the management of customer's emotions and its harmonical use on design and it aims on the embodiment of new ergonomics design. In the center, it has analyzed the criteria and characteristics for the 'User First Design' and has concluded the design direction and components to a concrete idea and proposed prototypes, which may becomes a good example for train interior design later on. And not at least it proposes a direction which may become a guideline of ergonomic design to secure competition capacity.

• 제어로봇시스템학회논문지
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• 제13권4호
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• pp.304-308
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• 2007

This paper deals with ANN(Artificial Neural Networks) and its application to automatic ship berthing. Due to the characteristic of ship's manoeuvre comparing with other moving objects on land, it has been known that the automatic control for ship's berthing cannot cope with various berthing situations such as various port shape and approaching directions. for these reasons. the study on automatic berthing using ANN usually have been carried out based on one port shape and predetermined approaching direction. In this paper, new algorithm with ANN controller was suggested to cope with these problems. Under newly suggested algorithm, the controller can select appropriate weights on the link of neural networks according to various situations. so the ship can maintain stable berthing operation even in different situations. Numerical simulations are carried out with this control system to find its improvement.

• 한국유체기계학회 논문집
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• 제3권4호
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• pp.15-21
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• 2000

An anemometer employing the bulk PTC thermistor as the sensing element is investigated in this study. The numerical and experimental works are carried out to improve the sensitivity problem of the element by focusing fluid dynamics point of view. The typical shape of the sensing element has been used as a rectangular type, but this shape has a sensitivity problem because of flow separations on the sharp edge when the flow direction is different from that of the sensing element. In order to reduce the reading error, the installer has to be very careful about the flow direction. The reading error fluctuation by time as well as the sensitivity problem can be improved considerably through this study. It can be concluded that the small change of the sensor shape can improve the performance of the flow sensor.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.664-667
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• 2003

Super In Plane Switching (S-IPS) technology is applied for large TFT-LCD panels used in TV applications. It has a lot of advantages in comparison to the alternative, VA technology. S-IPS shows excellent viewing angle properties and fast response time between intermediate gray levels. If the performance parameters which describe the actual visual performance are considered, S-IPS is much more advantageous.$^{1)}$ However, it shows relatively low contrast ratio in diagonal direction compared to viewing angle characteristic in upper/down direction in S-IPS. In order to compensate the relatively low diagonal contrast ratio, a newly designed optical film was applied and the truly wide view angle of a S-IPS TW(True Wide)-IPS) was achieved. Our newly developed 30-inch TFT-LCD panel reveals TW-IPS that is optimized for TV application