• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.53-59
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• 2000

A numerical method to predict responses of very large floating structures in wave is suggested using source-dipole distribution method. The deflection of the plate is calculated by the finite element method in terms of rigidity matrix of each node. The calculated results for a plate are compared with the experimental ones.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.3 no.1
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• pp.29-34
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• 2000

This paper proposes a long-term prediction of offshore structures in ocean waves. All short-term statistics is generated by the simulation for all the combinations of significant wave heights and spectral peak periods. The simulation has been tested first on linear system, whose analytic solution is known, to verify if the simulation works accurately. Then the scheme was applied to the nonlinear system. This paper demonstrated that the proposed scheme could be an efficient tool in estimating the response of offshore structures.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.431-438
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• 2000

The purpose of this paper is to design the menu of mobile phone based on the impression engineering. Free response survey analysis was used to collect impression data on mobile phone functions with time interval. Simultaneity analysis was applied to finding the relationship among selected impression. We cluster a set of the related impression so as to design the menu of a mobile phone accordingly. This research is expected to contribute to the improvement of customer satisfaction by reflecting customer's impression in the process of product design.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.234-235
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• 2000

최근에 많이 사용되는 휴대용 기기의 표시장치인 액정표시장치(LCD)에는 반사형이 많이 사용되고 있다. 반사형 LCD는 전력소모의 많은 부분을 차지하는 backlight를 주변광원으로 대체하여 전력소모를 줄일 수 있는 표시장치로 많이 연구되고 있다. 특히, 반사형 LCD는 밝기면에서 우수한 single-polarizer mode가 적합하다$^{1.3}$ . 그러나 single-polarizer mode는 two-polarizer mode와 비교해서 dark 상태에서의 누설광이 많이 발생하여 대비비가 저하되는 단점이 있다. 이 점을 보완하기 위하여 전 파장 영역에서 편광판에 의해 반사광이 차단될 수 있도록 설계를 했다. (중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.232-236
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• 2000

To provide model parameters for servo control system design, dynamic characteristics of a piezoelectric microactuator for hard disk drive(HDD) were investigated. At first frequency response characteristics was measured and a second order model was proposed. Here the amplitude dependent dynamic characteristics such as low frequency gain and damping ratio were studied. In addition, the load current and equivalent impedance of the piezoelectric actuator were measured by varying excitation voltage and frequency. At last, the super-harmonic resonance of the piezoelectric actuator was discussed.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.17-20
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• 2000

In a digital communication system, the transmission channel may introduce error into the digital signal being transmitted. It would be useful if a process could be devised so that the error could be removed in order to recover the transmitted digital signal. We design a corrective filter that is inverse filter, which will generate an output signal identical to the input signal. in order for two systems connected in cascade to produce an output which is identical to the input signal, the over-all unit sample response of the cascade connection must be a unit sample function.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.56
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• pp.55-64
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• 2000

There is more than a single quality characteristic and they are often of varying or mixed target types. The purpose of this paper is to develop general strategies for solving the multiple response robust design problem. The desirability function provides an important tool to solve problems that have different types of target since the desirability values all the range between zero and one. Several combinations of arithmetic averages, geometric averages, and standard deviations are used in the various strategies to find the best design point.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.181.2-182
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• 2000

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.354-363
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• 1996

This study was conducted to investigate the repeated dose toxicity of DA-9601, an antiulcer agent of Artemisia app. extract, in rats. DA-9601 was administered orally once a day for 4 weeks to 10 males and 10 females per group at doses of 0(vehicle control), 125, 500 or 2000 mg/kg/day. Throughout the study, no treatment-related deaths and clinical signs were observed. In female rats receiving 125 mg/kg of DA-9601, water consumption increased slightly on day 4, 11 and 25. Hematological examination showed a decrease of MCV and an increase of PLT in male rats at the doses of 500 and 2000 mg/kg groups. Blood biochemistry revealed slight decreases of cholesterol, BUN and Na in male rats and decreases of total bilirubin and creatinine and slight increases of globulin and Cl in female rats. The organ weights at the end of 4 weeks showed slight changes in some organs of treated groups. But, all these changes were not considered to be of toxicological importance, because they did not show dose-response relationship and relevance to gross and microscopic findings. Histopathologically, abnormal treatment-related changes were not observed in any organ and target organs were not detected. On the basis of these results, the NOAEL(no-observed-adverse-effect level) of DA-9601 was estimated to be more than 2000 mg/kg/day under the conditions tested.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.544-552
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• 2001

Korea is classified into low and moderate seismic zone from the view-point of seismic hazard level. Korean seismic provisions has been developed based on UBC and ATC 3-06. Thus, in calculation of design base shear according to Korean provisions response modification factor (R) is included in the formula of design base shear. The major role of this factor is to reduce the elastic design base shear whereby structures can behave in inelastic range during design level earthquake ground motions(mean return period of 475 yrs.). R factor is assigned according to material and structural systems. In this study, R factor for bearing wall system is considered. Most of the walls of apartment buildings in Korea resist gravity and seismic loads simultaneously so that this wall system can be classified into bearing wall system. Structural details of these walls are different from those used in Japan and U.S.. They are all rectangular in sectional shape rather than barbell in shape, and also have special lateral reinforcement details at the boundaries of a wall. In Korean seismic design provisions(1988), two different values(3.0 and 3.5) of R factor are assigned to the bearing wall systems according to the wall details. However, in updated seismic provisions(2000), only one value is assigned to R factor(3.0) irrespective of wall details. In this study, the design base shear values in Korean seismic design provisions(1988, 2000), ATC 3-06, UBC are compared. Also experimental study was carried out to evaluate the seismic performance of structural walls. For this purpose, five test specimens were made which have special details used in apartment bearing wall systems in Korea. Based on the results of this study, response modification factor for bearing wall system is discussed.