• Structural Engineering and Mechanics
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• v.20 no.2
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• pp.143-160
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• 2005

Modal analysis of cracked cantilever composite beams, made of graphite-fibre reinforced polyamide, is studied. By using the finite element and component mode synthesis methods, a numeric model applicable to investigate the vibration of cracked composite beams is developed. In this new approach, from the crack section, the composite beam separated into two parts coupled by a flexibility matrix taking into account the interaction forces. These forces are derived from the fracture mechanics theory as the inverse of the compliance matrix calculated with the proper stress intensity factors and strain energy release rate expressions. Numerical results are obtained for modal analysis of composite beams with a transverse non-propagating open crack, addressing the effects of the location and depth of the crack, and the volume fraction and orientation of the fibre on the natural frequencies and mode shapes. By means of modal data, the position and dimension of the defect can be found. The results of the study confirmed that presented method is suitable for the vibration analysis of cracked cantilever composite beams. Present technique can be easily extended to composite plates and shells.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.309-312
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• 2007

수학, 물리학, 전자전기공학에서 취급하는 수치 자료는 매우 크거나 정밀도가 높으므로 계산과정에서 흔히 오버플로우나 언더플로우가 발생할 수 있다. 본 연구는 이런 현상을 최소화하기 위하여 겁수(Kalpa Number) 표현방법을 제안한다. 겁수는 고정소수점수와 부동소수점수를 저장할 수 있는 자료형을 제공하며, 정수형 및 실수형의 지수와 가수부분을 문자형 배열에 저장함으로써 매우 큰 수를 취급할 수 있다. 이를 이용하여 프로그램을 작성하면 베르누이 수나 전자의 움직임과 관련된 계산 프로그램에서 오버플로우나 언더플로우를 최소화할 수 있다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.350-353
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• 2003

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experiment81 results of the simulation.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.425-429
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• 2008

We investigated algorithm to detect and characterize interstitial lung abnormalities seen at chest radiographs. This method includes a process of 4 directional Laplaction-Gaussian filtering, and a process of linear opacity judgment. Two regions of interest (ROIs) were selected in each right lung of patients, and these ROIs were processed by our computer-analyzing system. For quantitative analysis of interstitial opacities, the radiographic index, which is the percentage of opacity areas in a ROI, was obtained and evaluated in the images. From or result, abnormal lungs were well differentiated from normal lungs. In our algorithm, the processing results were not only given as the numeric data named "radiographic index" but also confirmed with radiologists observation on CRT. The approach, by which the interstitial abnormalities themselves are extracted, is good enough because the results can be confirmed by the observations of radiologists. In conclusion, our system is useful for the detection and characterization of interstitial lung abnormalities.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.120-130
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• 1993

In the analysis of automobile exhaust system, the exciting forces from the engine determine the dynamic behavior of the system and the dynamic characteristics influence the riding quality. Therefore, the identification of the force in numeric value is quite important for the vibrational reduction. However, the value is difficult to obtain by experiments due to harsh conditions around the engine. In this research, an optimization technology is adopted to evaluate the exciting forces. An experimental method is conducted for the verification of the finite element modeling. Displacements on the end of the exhaust system are measured under the idling environment. cost function is set up to minimize the differences between the displacements of the numerical simulation and the experiment. Design variables are the components of the exciting forces. That is, optimization is utilized to estimate the forces with existing data. Excellent estimations have been calculated efficiently and the information is used again for the forced vibration of the exhaust system.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.298-302
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• 2003

Inorganic Crystal Structure Database, the essential information in the chemistry field for synthesis and property research of inorganic materials, has been constructed. The data source is obtained from the FIZ-Karlsruhe, about 65, 000 records of the coverage period is 1915 year to present. This paper describes the database schema and retrieval system of the Inorganic Crystal Structure Database designed for the speedy and efficient retrieval, especially developed into supporting numeric retrieval of the crystal structure cell parameter.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1015-1018
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• 2003

본 논문은 날로 증가하는 데이터 처리 요구를 데이터 처리 전용 칩을 이용하여 데이터베이스, 데이터 마이닝, 또는 전문가 시스템 통과 같이 데이터 비교연산에 시간을 많이 소모하는 응용 소프트웨어의 처리 속도를 최소화 할 수 있는 시스템을 제안한다. 본 시스템은 기존의 숫자처리(numeric processing)보다는 기호처리(symbolic processing)를 위해서 관계 연산(relation operation) 모듈을 이용하여 입력된 데이터들을 하드웨어 레벨에서 고속으로 처리한다. 본 시스템은 칩으로 설계되어 하드디스크 레벨에서 시스템을 가속 시린 수도 있고, IP(Intellectual Property)로 구현되어 SoC(System-on-a-chip)의 한 모듈로서 프로세서 레벨에서 시스템을 가속시킬 수도 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.465-468
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• 2001

An aerostatic stage has frictionless behavior, so it has a advantage of investigation into positioning characteristics. A one-dimensional aerostatic ceramic stage with ballscrew driven and laser scale feedback system is manufactured, aiming at investigating positioning characteristic of ultra-precision stage. We confirm, this ceramic aerostatic stage has a 10nm micro resolution, and can be reduced mean of position error by compensation of numeric control command. By means of analyzing relationship of position error and change of temperature, we build a on-line compensation algorithm of position error from the measured temperature data. So we can improve repeatability of ultra-precision stage up to 34%($0.095{\mu}$) of the normal condition.

• Journal of the Ergonomics Society of Korea
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• v.14 no.2
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• pp.15-24
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• 1995

The purpose of this study is to provide ergonomic research data for the redesign of the car license plate in Korea. Several alternatives having various combinations of fonts, stroke-width ratios, color contrasts, and arrays were considered in order to find the best one in terms of the reading-distance and the misreading-rate. Experiments investigating the reading-distance, misreading-rates were conducted. In addition, the alternatives were tested in a real driving situation. The results can be summarized as follows : The typography having mixed type numeric forms with quasi-Gothic and NAMEL, stroke-width ratio of 1:7 .approx. 1: 8, the black on yellow contrast showed a good reading-distance. The array with Hangul(showing territorial office and use-sign) at the upper row and 6 mumbers ( showing car class-sign and serial number) at the lower row showed relatively low misreading-rate.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.63-68
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• 2016

This thesis proposed an objective and accurate fundamental numeric data for the economics and business analysis of applicable CCS technology to plant using existing fossil fuel by analyzing the influence of process improvement for commercialization of Carbon Capture and Storage(CCS) technology, which enables storing $CO_2$ generated by fossil fuel by extracting before emitting to air and press until it becomes liquid, and development and performance improvement of new solvent on Total Life Cycle Cost(TLC) of CCS.