• 한국소음진동공학회논문집
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• 제14권10호
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• pp.999-1006
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• 2004

Recently, the ride comfort problem becomes increasingly important because of today's needs for train speedup. The railway has the track irregularities which cause vibrations, such as rail joints, turnout, level crossing, transition corves and super-elevation ramps, and variations in the track level(z-axis) and the gauge(y-axis). In Korea, the service run of the high speed train has been made since the 1st of April, 2004. The commercial high-speed trains must be run on the compound lines which are composed of high-speed line and conventional line. The high speed lines in both Kyoungbu line and Honam line have 57.5％ and 33.8％, respectively In this Paper, the ride comfort has been reviewed by the various experimental methods when the high-speed trains are operated on both Kyoungbu line and Honam line. The results show that the high-speed train has no problems from the viewpoint of the comfort ride during the operation on the high speed line and conventional line.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.144-146
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• 2003

• 한국도로학회논문집
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• 제18권5호
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• pp.127-134
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• 2016

PURPOSES : Visibility of lanes on the road improves as retro-reflectivity rises. This helps reduce traffic accidents at nighttime or in bad weather. This study aimed to evaluate the effects of improved visibility on reduction of traffic accidents when the color of the lane in the median of the highway was changed from yellow to white. METHODS : In order to evaluate the accident reduction effect of the white left shoulder line, Hauer (1997)'s Comparison-Group method was chosen as an analysis methodology. The JungBu-2 highway, which is equipped with the white left shoulder line and is in trial operation, was chosen as a target for analysis. Data of accidents for 10 months before and after installation was collected and analyzed. In addition to the number of accidents, the types of accidents were classified into nighttime accidents, accidents in bad weather, and median collisions. The accident reduction effect of improved visibility of lanes was analyzed. RESULTS : The analysis' finding showed that installation of the white left shoulder line decreased the number of accidents by 28%. Moreover, improvement in visibility was effective in reducing nighttime accidents by 67.63%, accidents in bad weather by 55.19%, and median collisions by 48.55%. CONCLUSIONS : Based on the analysis' results in this study, it was concluded that white left shoulder line on the freeway contributed to reduce traffic accidents, especially nighttime accidents, accidents in bad weather, and median collisions.

• Journal of Welding and Joining
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• 제29권2호
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• pp.40-45
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• 2011

The purpose of this study is to establish the optimum line heating condition to straighten the excessive bending distortion of a thin plate welded structure. For it, the extensive FEA and experiments were performed to evaluate the effect of heat source, heating speed and position on the straightening of a thin plate welded structure. In accordance with the results obtained by FEA and experiments, the straightening effect of line heating was strongly depends on the variables used in this study. With the results, the optimum line heating condition was established by using the response surface method and verified through comparing it with the numerical analysis result.

• 대한인간공학회지
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• 제15권1호
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• pp.1-14
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• 1996

Menu-driven interfaces are frequently employed for user interfaces on many electronic products. Due to space constraint, a single or multi-line display is popularly used to show menu items unlike the software interfaces. Single or multi-line display present 8 .approx. 21. characters on an LCD screen and the user selects items using a series of button pushes. Multi-line displays are different from the single-line ones in the following aspects. First, they can present multiple line of information at the same time. Second, they can present menu items in a various way compared to single-line ones. However, due to their space constraint multi-line displays have many limitations compared to ordinary displays which usually use 14" screens. Therefore, guidelines are necessary for designing efficent multi-line display menus interfaces. In this study, a human factors experiment was conducted to examine the effects of three design variables which might affect the usability of a multi-line display menus. Factors investigated include menu structure, number of lines on the display, and item presentation method. Usability of the multi-line display menus was measured quantitatively in terms of four different aspects: speed, accuracy, inefficiency and preference. The analysis of variance was used not only to analyze the main effects of the factors and their interactions but also to see the differences between the single-line display menus and multi-line display ones. A set of design guidelines drawn from this study can be applied to the design of the user interfaces of a various types of electronic consumer products.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3732-3744
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• 2022

To investigate the effects of ocean conditions on the thermal stress and deformation caused by thermal stratification of a pressurizer surge line in a floating nuclear power plant (FNPP), the finite element simulation platform ANSYS Workbench is utilized to conduct the fluid-solid-thermal coupling transient analysis of the surge line under normal "wave-out" condition (no motion) and under ocean conditions (rolling and pitching), generating the transient response characteristics of temperature distribution, thermal stress and thermal deformation inside the surge line. By comparing the calculated results for the three motion conditions, it is found that ocean conditions can significantly improve the thermal stratification phenomenon within the surge line, but may also result in periodic oscillations in the temperature, thermal stress, and thermal deformation of the surge line. Parts of the surge line that are more susceptible to thermal fatigue damage or failure are determined. According to calculation results, the improvements are recommended for pipeline structure to reduce the effects of thermal oscillation caused by ocean conditions. The analysis method used in this study is beneficial for designing and optimizing the pipeline structure of a floating nuclear power plant, as well as for increasing its safety.

• 한국항해학회지
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• 제22권1호
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• pp.15-22
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• 1998

In this paper, discontinuity parts in microstrip line with $\lambda$/4 open stub and one in crank type have been anlayzed by using FDTD(Finite-Difference Time-Domain) analysis method. The noise components, in this case, are occred at the discontinuites of the given microstrip lines, the complex poles were extracted by the analysis using GPOF (Generalized Pencil-of Function) method from electric field of time domain. It has, then, been found that the noise level and the noise frequency components included in signal could be derived.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.432-437
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• 2004

Since the characteristic frequency is decreased in proportion to the fault distance, the characteristic frequency component may be insufficiently eliminated by a low-pass filter on a long transmission line. In order to set a standard for the cut-off frequency of the low-pass filter, this paper proposes a method for obtaining the characteristic frequencies due to line faults. The application results of the proposed method are presented for line to ground (LG) faults and line to line (LL) faults on a 345 kV 200 km overhead transmission line. The EMTP is used to generate fault signals under different fault locations and fault inception angles. By comparison between the characteristic frequencies obtained from the proposed method and the EMTP simulation, it is shown that the proposed method accurately obtains the characteristic frequency.

• 전기학회논문지P
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• 제57권2호
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• pp.176-180
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• 2008

A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of transformer in a substation by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• 동아시아경상학회지
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• 제4권1호
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• pp.16-21
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• 2016

This study analyzed the successful case of Naver LINE's entry into the Japanese market. LINE pursued a strategy of establishing its dominance early on and implemented localization for Japan and thereby achieved success in the Japanese market. The various strategies adopted by LINE allowed it to win over 80% of the market share in Japan and function as a nationally ubiquitous mobile messenger. The conclusions to be drawn from our LINE analysis is that LINE must implement localization strategies suited to the characteristics of each country, as it had done successfully in Japan. In the Asian region, it should retain the platform that provides various contents while pursuing a localization strategy to secure competitive edge, by offering emoticons suitable for each country, such as Ramadan emoticons in Islamic regions.