• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.193-200
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• 1997

Current seismic design code is based of the assumption that the designed structures would be behaved inelastically during a severe earthquake ground motion. For this reason, seismic design forces calculated by seismic codes are much lower than the forces generated by design earthquakes which makes structures responding elastically. Present procedures for calculating seismic design forces are based on the use of elastic spectra reduced by a strength reduction factors known as "response modificaion factor". Because these factors were determined empirically, it is difficult to know how much inelastic behaviors of the structures exhibit. In this study, base shear forces required to maintain target ductility ratio were first calculated from nonlinear dynamic analysis on the single degree of freedom system. And then, base shear foeces specified in seismic design code compare with above results. If the strength(base shear) required strength should be filled by overstrength and/or redundancy. Therefore, overstrength of moment resisting frame structure will be estimated from the results of static nonlinear analysis(push-over analysis).analysis).

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.611-617
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• 2009

The primary purpose of this study was to analysis quantitatively the degree of injury and/or the progress of treatment for physical impairment. This study provided a more detailed study that evaluates all test parameters including maximum grip strength, duration of operation, average grip strength, acceleration work, dynamic endurance time and percent change in static endurance. Also, a complete database management system is developed and used to store related training, evaluation, and personal information. In addition, the system is developed a grip sensor using load.cell transducer (${\leq}60kg$). The system will be efficient to operate and convenient to use, furthermore, it can be helped for understanding and analysis the progress of a patient during a doctor's rehabilitation program.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.77-88
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• 2010

In this study, 1 g shaking table group pile tests were performed for various conditions of subgrade and pile spacing. The pile spacing was changed from three to seven times of pile diameters. It could be confirmed that the dynamic p-y curves for the group pile observed as the results of a series of shaking table tests show difference according to the pile spacing, the pile location within the pile group, the relative density of subgrade and the excess pore pressure during earthquake. The dynamic p-multipliers were calculated by comparing the dynamic p-y backbone curves of a single pile suggested by Yang (2009) and dynamic p-y curves for the group pile. Dynamic p-multiplier values overall increase as the relative density of subgrade and amplitude of input acceleration increase. The dynamic group pile effect was neglected, if the pile spacing was seven times as large as pile diameters. It was found that the exisiting p-multiplier values suggested by various researchers for the static and dynamic loading, and the values recommended by globally used specifications show difference with the test results by up to 0.7 (approximately 70%). Therefore, the dynamic p-multipliers were newly suggested according to the pile spacing and the relative density of subgrade using the test results.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.788-793
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• 2005

This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used electric vehicles with 80 kW per car that are produced Mitsubishi Heavy Industries Ltd, and one car is constructed with SIV(Static Inverter), VVVF(Variable Voltage and Variable Frequency) and two induction motor. The operated vehicles in the IAT system are rapidly changing DC load, and at a feeding substation, 3-phase electric power is transferred to DC 750 V by rectifier. Since, vehicles are also changing continuously, the voltages for the DC load fluctuate in the IAT system, and moreover, the fluctuating voltages generate high-order harmonics. This means that there is the difficulty in maintaining power quality in KEPCO systems' side. Therefore, the power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper. The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

• Journal of KSNVE
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• v.9 no.5
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• pp.975-983
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• 1999

This paper describes the dynamic characteristics of the joint structures in case of using the simplified beam model in the F. E. analysis. The modeling errors, when replace the shell with the beam, are investigated through F. E. normal modes analysis. Normal mode analysis were performed to obtain the natural frequencies of the L and T shaped joints with various type of channels. The results were analyzed to access the effects of the models on the accuracy of F.E. analysis by identifying the geometric factors which cause the error. The geometric factors considered are joint angle, channel length, thickness and area ratio of the hollow section to the filled one. The joint stiffness evaluation technique is developed in this study using normal modes analysis with Lumped Mass. With this method, the progressively improved results of F. E. analysis are obtained using the simplified beam model. The static and normal modes analysis are performed with the joint stiffness values obtained by the Kazunori Shimonkakis' virtual stiffness method and the proposed method and these simplified modeling errors are compared.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.238-240
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• 2005

This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used electric vehicles with 80 kW per car that are produced Mitsubishi Heavy Industries Ltd, and one car is constructed with SIV(Static Inverter), VVVF controller and two induction motor. The operated vehicles in the IAT system are rapidly changing DC load and at a feeding substation, 3-phase electric power is transferred to DC 750 V by rectifier. Since, vehicles are also changing continuously, the voltages for the load fluctuate in the IAT system, and moreover, the fluctuating voltages generate high-order har -monies. This means that there is the difficulty in maintaining power quality in KEPCO systems' side. Therefore, the power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

• Journal of the Korean Society of Costume
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• v.59 no.9
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• pp.16-25
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• 2009

The purpose of this study is to develop pattern of a Upper Garment Prototype for late elementary school aged girls. The body of late elementary school aged girls changes steadily up to the adult and is characterized by its periodic noticeable physical distinctions. This study is selected a test pattern from 3 existing patterns through a preliminary wearing test, conducted wearing tests, and sensory evaluations three times to review and improve the pattern, and presented the pattern of late elementary school aged girls. The research pattern was developed considering aesthetic and functional aspect. The average score of sensory evaluation on appearance was 4.13 for the research pattern, which was higher than 2.74 for the test pattern. The according to the results of verifying significant differences in the test items between the two patterns through the t-test, in the items such as pleats in the line of a waist, the ease of the girth of a waist, the location of shoulder line was superior to the test pattern. The average score of the sensory evaluation on functionality was 4.91 for the research pattern, which was higher than 3.90 for the test pattern. The research pattern is superior to the test pattern in static posture, dynamic posture than the test pattern.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.314-324
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• 1996

A high speed NMR quality evaluation sensor was designed , constructed and tested . The device consists of an NMR spectrometer coupled to a conveyor system. The conveyor was run at speeds ranging from 0 to 250 mm/s. Spectral of avocado fruits and one-dimensional magnetic resonance images of pickled olives were acquired while the samples were moving on a conveyor belt mounted through a 20Tesla NMR magnet with a 20 mm diameter surface coil and a 150 mm diameter imaging coil respectively. Fro a magnetic resonance spectrum analysis, motion through variations in the magnetic field tends to narrow spectral line width just like using sample rotation in high resolution NMR to narrow spectral line width. Spectrum analysis was used to detect the dry weight of avocado fruits using the ratio oil and water resonance peaks. Good correlations maximum r=0.970@ 50 mm/s and minimum r=0.894@250mm/s ) between oil and water resonance peak ratio and dry weight of avocados were observed at speeds ra ging from0 to 250mm/s. For the application of magnetic resonance imaging (MRI) method, the projections were used to distinguish between pitted and non-pitted olives . Effect of fruit position in the coil was tested and coil degree effects were noticed when projects were generated under dynamic conditions. Various belt speeds (up to 250mm/s) were tested and detection results were compared to static measurements. Higher classification errors were occurred at dynamic conditions compared to errors while olives were at rest.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.103-110
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• 2009

We are witnessing rapid increase of the number of wireless devices available today such as cell phones, PDAs, Wibro enabled devices. Because of the inherent limitation of the bandwidth available for wireless channels, broadcast systems have attracted the attention of the research community. The main problem in this area is to develop an efficient broadcast program. In this paper, we propose a dynamic broadcast method that overcomes the limitations of static broadcast programs. It optimizes the scheduling based on the probabilistic model of user requests. We show that dynamic broadcast system can indeed improve the quality of service using user requests. This paper extends our previous work in [1] to include more thorough explanation of the proposed methodology and diverse performance evaluation models.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.565-570
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• 1998

SiCp/6061AI 복합재료의 파괴인성을 평가하기 위하여 정적파괴인성에 대해서는 복수시험편법을, 동적파괴인성시험에 대해서는 stop block법을 실시하였다. 주균열은 예비균열의 선단에서 시험편두께방향 전역에 걸쳐서 일시에 발생하는 것이 아니고, 균열발생의 초기단계에서 국부적으로 형성된 균열이 시험편두께방향으로의 균열의 확장을 완료한 후 주균열로 이행해 간다. 정적 및 동적시험에서 컴플라이언스변화율법에 의해 검출된 균열발생점은 균열확장의 완료점과 거의 일치하고 있기 때문에 본 재료의 파괴인성 결정에 유효하다. 본 재료에서 동적파괴인성치는 정적파괴인성치보다 크게 나타났다. 이것은 동적충격시 입자파괴에 의한 에너지의 흡수.분산효과와 균열진전경로의 큰 편향에 기인한다고 생각된다.