• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.1-7
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• 2008

The paper is to solve the problem of existing sound system, which has difficulties of system organization and the increase of additional install cost and unfriendly interior. To solve the existing system, we drew the new sound system based on PLC and studied it. A transmitter and a receiver were designed using the PLC chip INT5500CS. Sound system was configured with a CD player that sound signals are sent from the transmitter and a speaker connected to the receiver. For analysis of characteristics of this system, a USBPre external sound card and Smaart Live 5 which is a PC-based sound measuring program were added. As a result of our experiment, the measured signal level is $2{\sim}3$[dB] lower than reference signal, latency is 16.69[ms] and the specific character of coherency is bad in high frequency band. Otherwise, this system transmits and receives signals over 90[%] in good condition as a result of measuring pink noise, frequency(1kHz), and phase, magnitude. In view of the result so far achieved, the system designed our team has excellent performance, it resolves defect of existing audio signal transmition system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4762-4767
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• 2012

The AF track circuit that detecting train position and transmitting various train control data for DTG to the train on-board is composed of single operation system. If a failure occurs on this system, the driver should be operate the train by manually until the system is restored, because the system cannot control switch machines and signals by automatically. In this process the human error affects to the train delay, collision, derailment and critical safety accident. Therefore, this document has analyzed the effects that each failure mode influences on system and train, and quantified the failure valuation point and class. Basis on this quantified analysis result, MTBF increased and MTTR decreased and failure number also decreased by adopting the independent installation of power supply, the replacement of defected capacitors, the installation of resister cooling system and the improvement of maintenance methods. And the failure factors of AF track circuits were decreased by conducting the preventive maintenance which is a quantitative way of maintenance system by experience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4849-4854
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• 2015

It has been often occurred for the outside components(BU, SVaC, DB) of UM71c AF track circuits to be broken down caused by some pieces of falling ice in the winter time or by infrastructure repairing equipments while facility maintenance works since 2004, opening of Kyeongbu High Speed Rail Express. In this paper, we proposed that we could move the outside components of UM71c track circuit out of wayside from present place. Then we can assure that the life time of those components would be extended. So we simulated the electrical characteristics by changing cable length using MATLAB Simulinks and we designed the compensation capacitor. Also, we obtained the same results as those of simulation by field demonstration test on site. The design specifications obtained from this field verification test could be applied in the absent section of track circuit, if only have a little more intensified research to compensate changed electrical characteristics and to redesign inner impedance of the track circuit.

• Journal of the Korean Society of School Health
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• v.15 no.2
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• pp.233-248
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• 2002

Purpose : Sexual abuse especially in younger group have been growing. This study was performed to propose the fundamental data for developing early education program to prevent damage from sexual harassment in elementary school students. Method : Questionnaire survey on cognitions and experiences about sexual harassment was done on 3125 elementary school students from seven elementary schools in Busan area from January to March, 2002. Data analysis was done with SPSS (ver 10.0). Results : Though 82% of the students have ever herd about sexual harassment previously, but self assessment of 'well-known' was only 5%. About 40% of them have ever experienced audio-visual sexual materials mainly through PC (18%), media (14%), etc. And, 60% of them have ever educated about sexual harassment. In cognitions, they agreed 'unwanted touch', 'intentional showing his (her) own body', 'send lewd mails and pictures', but disagreed 'ask massage from aged', 'gaudy joke' as one of sexual harassment. In attitudes, 'no response', 'defense with friends and family', 'express unpleasantness apparently' were desirable pattern, instead, 'his (her) own responsibility', 'problem only between person concerned', 'neglect is the best way' were undesirable. About 24% of them have ever experienced at least one of the fifteen types of sexual harassment with major types of lewd mails pictures (11%), hugging (5%), ask massage (4.7%) and unwanted touch (3.3%). The experience by gender was higher in girls (25.0%) than boys (22.4%) with no statistical significance. The mean level of cognition and attitude out of one hundred was $70.3{\pm}28.1$ and $73.5{\pm}15.9$, respectively. The mean frequency of experience was $0.4{\pm}1.1$ times. The level of cognition and attitude was higher in girls, 6th graders, and in ever educated group (p<0.001). Conclusions : The cognition level of elementary school students about sexual harassment assessed considerable. And, they also experienced several types of sexual harassment, though not too much. Therefore, compatible education program let them able to protect themselves from sexual harassment should be developed and applied even in early school age.

• Analytical Science and Technology
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• v.24 no.5
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• pp.368-377
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• 2011

In this study, we analyzed the relationship between noise and air pollution from 6 residential sites from 6 districts in Seoul. The survey of all noise date obtained from 6 sites were also compared between road and nonroad area and between active (06:00-22:00) and inactive time bands (22:00-06:00). Comparison of the data between two time bands indicates that their differences are not large enough. On the other hand, if comparison of data is made by correlation analysis for road and non-road areas, strong correlations between noise levels and air pollution tend to be prevalent consistently in road area relative to the non-road area. In contrast, a correlation between noise levels and air pollution tends to decrease at the road area in inactive period relative to active period.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.654-664
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• 2011

A field campaign of magnetotelluric (MT) and audio-frequency MT (AMT) survey was done at 36 measurement points as a complementary for the previous 44 MT measurements completed during the period of 2005-2006. The purpose of additional MT survey is to investigate the possible fracture system in Seokmo Island, which is conceived to be crucial in accumulation and migration of geothermal hot spring in this area. We have done 2D and 3D inversions of overall MT and AMT data distributed on a grid to interpret subsurface of extended area. The inversion results reveal that at least two major faults are imaged in the inversion results, one of which is in NNE-SWW with steep dip, and another is in E-W direction.

• Tunnel and Underground Space
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• v.19 no.5
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• pp.407-420
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• 2009

In this study geostatistical technique using indicator kriging was performed to evaluate the optimal rock mass classification by integrating the various geophysical information such as borehole data and geophysical data. To get the optimal kriging result, it is necessary to devise the suitable technique to integrate the hard (borehole) and soft (geophysical) data effectively. Also, the model parameters of the variogram must be determined as a priori procedure. Iterative non-linear inversion method was implemented to determine the model parameters of theoretical variogram. To verify the algorithm, behaviour of object function and precision of convergence were investigated, revealing that gradient of the range is extremely small. This algorithm for the field data was applied to a mountainous area planned for a large-scale tunneling construction. As for a soft data, resistivity information from AMT survey is incorporated with RMR information from borehole data, a sort of hard data. Finally, RMR profiles were constructed and attempted to be interpreted at the tunnel elevation and the upper 1D level.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.149-156
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• 2010

There are elements for the game user get into the emotion of flow (the mental state of operation in which the person is fully immersed in what he or she is doing by a feeling of energized focus, full involvement, and success in the process of the activity). In game contents, for example, a considerable sophisticated application of 'sound' is one of the important elements must be considered for a qualified game development process. If a proper audio condition is satisfied, a game user is intrinsically solving problems by auditorial sense and the participant get into immersing into the game spontaneously. There are elements in game contents storytelling for the user to be in flow condition, this study will be analyzing a game user's flowing, especially with repetitive usage of sound. To be accurate, 'flow analysis' of Csikszentmihalyi. M, and 'flow factors' of Donna L. Hoffman & Thomas P. Novak, in addition, would be proper references in the research. comparing to a precedent study that analyzed a game and flow focused on visual elements. Ponpoko(Sigma Enterprise Inc., 1981) and Bio Hazard 4(Capcom, 2007) will be given as the main texts. To achieve the desired proposition in the study, user's reaction is monitored by listening repeatable and ordinary sound. Questionnaires are including Frequency Analysis, MANOVA(multivariate analysis of variance).

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.660-670
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• 2002

The purposes of this study were to categorize the type of student-student interaction and analyze the pattern of group interaction by cognitive level in interactive science inquiry experiments. For this study, two homogeneous and two heterogeneous groups by cognitive level were selected. Social interactions during group discussions were audio/video taped. The types of student's interaction were classified as intellectual and emotional aspects. Intellectual aspects were consisted of asking question, response, making suggestion, receiving opinion and then further coded by interaction level. Emotional aspects were consisted of relevance to behavioral participation, relevance to students' feeling, reaction to opinion. Interaction frequency in the intellectual and emotional aspect between homogeneous and heterogeneous group were compared to analyze interaction pattern. The results of this study showed that in intellectual aspect the frequency and quality of interaction in homogeneous group was higher than that in heterogeneous group. In emotional aspect. homogeneous group more showed such negative attitude as lack of confidence and dissatisfaction than heterogeneous group, on the other hand showed acceptable mood to be able to accept or object to peer's opinion. Some educational implications were drawn.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.38-45
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• 2016

The power transformation system of High Speed rolling stocks like KTX-Sancheon has shown excellent control capacities in the areas of riding comfortability, switching efficiency, safety and energy consumption due to technical developments in power-electronics, high speed & large scale integrated semiconductors and microprocessors. However, harmonics from IGBT, a high speed switching device used in the Convertor & Invertor equipment of rolling stocks have given rise to various problems in transformer substations, signaling systems, data transmission systems and facility monitoring systems. Especially, TI21 non-insulated track circuits have malfunctioned due to the influence of returning current harmonics which were generated at around of integer times of the number of power transformation equipment in the frequency domain. This paper, measures and analyzes various schemes to analyze the traveling path of the returning current harmonics generated due to the relationship between the rolling stocks and track circuits on site. Ultimately, theseschemes will be used to design high speed rolling stocks, AF track circuits and a common grounding network.