• Journal of the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.104-112
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• 1997

Line heating process has been used in forming hull surfaces long before and it has depended on skillful workers. As the reduction of production cost is major concern of shipbuilding companies, line heating work must be improved for higher productivity. In this paper, as the first step to automatic hull forming, a method is proposed to predict deformations due to line heating. It includes a simplified thermal elasto-plastic analysis to increase computing efficiency and to do real time visualization of deformed shapes. For the prediction of deformation, a method to estimate heat flux of the torch is also introduced. Predicted deformations for line heated plates show good agreement with experimental results. The proposed method can be used in control and simulation of line heating process with ease.

• Journal of Korean Society of Transportation
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• v.7 no.2
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• pp.53-69
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• 1989

The management of subway business in large cities has recently become more difficult because of increased construction and operation costs. To cope with this situation, it is necessary to examine the methods of obtaining returns on development profits of land value rises that occur due to subway construction along subway lines, For this purpose, we examined the actual situation of rises in land values brought about by the construction of subway line #3 and line #4 in Seoul with application of three methods. In this research, we have calculated a basis of the development profits produced by the construction of subway line. According to the results, development profits produced by the subway construction differ depending on the method adopted. If, however, we accept line comparison analysis method, the total development profits amount to 557,3 billion won that is equivalent to 37 percent construction cost.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.438-442
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• 2009

Voltage instability is a phenomenon that could occur in power systems due to stressed conditions. The result would be an occurrence of voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction is an important part of power system planning and operation, and can help ensure that voltage collapse due to voltage instability is avoided. Line outages in power systems may also cause voltage collapse, thereby implying the contingency in the system. Contingency problems caused by line outages have been identified as one of the main causes of voltage instability in power systems. This paper presents a new technique for contingency ranking based on voltage stability conditions in power systems. A new line stability index was formulated and used to identify the critical line outages and sensitive lines in the system. Line outage contingency ranking was performed on several loading conditions in order to identify the effect of an increase in loading to critical line outages. Correlation studies on the results obtained from contingency ranking and voltage stability analysis were also conducted, and it was found that line outages in weak lines would cause voltage instability conditions in a system. Subsequently, using the results from the contingency ranking, weak areas in the system can be identified. The proposed contingency ranking technique was tested on the IEEE reliability test system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1914-1921
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• 2011

When a railway vehicle passes through curves & transitions, the running speed must be improved by proposing the standards on the maximum running possibility speed of each section on conventional line (Dongdaegoo-Namsunghyun) considering derailment safety. In this paper, To improve the maximum running possibility speed of railway vehicle which passes through curves which have high risk of derailment, the track alignment conditions of conventional line (Dongdaegoo-Namsunghyun) that present transition curve length in current railway construction regulations are controlled. We presented elevation way about the section maximum running possibility speed in conventional line by analysis result.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.128-134
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• 2004

This paper presents a result of sound transmitting system with power line communication technique. Sound transmitting system is a transmitter which transmits modulated audio signal to power to power line and receiver which is capable of detecting it with earphone or speaker. It has been evaluated with the frequency characteristics and spectrum analysis. And, from the result of evaluation on the developed system, we confirmed the superior sound transmitting characteristics, and the possibility of application on a language laboratory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1425-1432
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• 1998

The propagation properties of Gaussian pulse signals on the microstrip line are investigated by the Kirschning & Jansen's approximated equation to meet the frequency range of a pulse, accuracy, and geometrical requiremtns of the microstrip line. The dispersion of pulse signals is analyzed regarding to the relative permittivity .epsilon.$_{r}$, substrate height h and strip width w of the microstrip line. To verify theoretical results, several samples of 50.OMEGA. microstrip lines are fabricated. And the characteristics of pulse propagation along these lines are simple measured using VNA(Vector Network Analyzer) with time-domain analysis function. A fairly good agreement has been found between the measured pulse waveforms and computer simulations.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3126-3128
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• 1999

In 22.9kV-Y overhead lines, if there is an earth fault, high fault current causes surge type over-voltages around this place. There are generally two types of earth faults. One is an earth fault which occurs when a voltage line falls to earth line. The other occurs when a voltage line directly falls to the earth. This study presents an analysis method on the earth fault.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.2
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• pp.26-32
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• 2004

This paper represents analysis on domestic technical regulation of high speed power line communications(PLC). Also it gives comparison of regulations for several countries which include U.S., Europe, and Japan. Power line communications radiates harmful interference in below 30MHz. This may intervene other radio equipments. The technical regulation must protect interference and provide clean radio environment. Finally this paper gives the proposal which is drafted by field tests for introducing high speed PLC.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.187-189
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• 2004

This paper investigates the effect of weather factors(such as winds, rain, snows, temperature, clouds and humidity) on transmission line outages. The result shows that weather variables have significant effects on the transmission line historical outages and the relationship between them is nonlinear. Multiple regression analysis using Logit model is proved to be appropriate in forecasting line failure rate in KEPCO systems. It could also provide system operators with useful informations about system operation and planing.

• Korean Journal of Human Ecology
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• v.19 no.1
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• pp.137-147
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• 2010

This research was designed to compare the subjective evaluation of texture image and preference by structure and sensible characteristics of women's suits fabrics between on- and off-line. 78 subjects who majored in fashion design evaluated the sensibility image and preference of 15 various kinds of specimens on- and off-line. Factor analysis, t-test, Pearson correlation and regression were used for a statistical analysis by SPSS WIN 13.0. The results of this study were as follows: 1. Women's suits fabrics were classified according to five sensibility image factors: 'classic', 'sophisticated', 'natural', 'characteristic', and 'practical'. 2. The results of the t-test showed that there were no differences between the on- and off-line evaluation of sensibility images. 3. The analysis of correlation indicated that the 'classic'-'sophisticated' and 'natural'- 'practical' sensibility images show a significant correlation between the two kinds of evaluation. 4. The results of regression revealed that 'sophisticated', 'characteristic' and 'practical' sensibility images had an effect on the purchase preference of women's suits fabrics. 5. 'Sophisticated', 'characteristic' and 'classic' sensibility images had an effect on the tactile preference of women's suits fabrics. 6. The structural characteristics of fabrics: thickness, weave and weight had an effect on the 'classic' sensibility image. Thickness had an effect on the 'sophisticated' sensibility image and fabric count had an effect on the 'characteristic' sensibility image.