• 경영과학
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• 제14권1호
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• pp.67-76
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• 1997

The most research on facility layout problems ignored the actual shapes of activity spaces and the aisles between activities. In many cases, the research also ignored the actual shape of building where the activities are to be arranged. In this paper, We present a block based layout technique that applies a genetic algorithm to search for a very good facility layout with horizontal aisles. From the extensive experiments for two different cases with respect to the shape of activity space, it was found that the proposed method generated better layouts than the ones obtained by applying Tam's algorithm in all test problems. The proposed algorithm showed about 10% improvement of performance on the average. We determined the best combination of the reproduction rule and the genetic operators with their probabilities for each test problem through the experiment.

• 한국생활과학회지
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• 제12권5호
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• pp.619-634
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• 2003

The purpose of this study was to the real situation of the safety education in the kindergarten by investigating the actual condition of the safety education and kindergarten teachers' knowledge about it. Questionnaire was adopted to obtain data required for pertinent analysis. The subjects were 234 kindergarten teachers located in Choongnam and Daejeon province. SPSSWIN v10.0 was utilized to calculate percentage, mean and standard deviation and to conduct t-test, one-way ANOVA and Duncan's multiple range test. The main results of this study were as follows. There was a significant difference between the actual condition of the safety education and kindergarten teachers' knowledge about it according to demographic variables. Especially, these differences were due to teachers' academic career, age, teaching experience, and the experience of bringing up children by themselves. The importance of the safety education must be emphasized. There were urgent needs to develop the way of teaching and the program about the safety education.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1550-1557
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• 2007

New locomotives 8100 & series 8200, based on the BR152 of German railway are suitable for heavy-duty freight traffic as well as for passenger transport. This electric locomotive had applied by trial petition way and 57 car is operating in mainline and industrial line until now. As matter of fact, this has a purpose to help designing and manufacturing the new electric locomotive in these day when almost all the line is changing into the electric fire line. This thesis has a purpose to check whether the actual simulation value properly apply and meet the designing value, comparing the result of the simulation for the performance of developed locomotive with the result of the type test which can be proceed in actual locomotive in korea (evaluating both the design value and the performance of the real locomotive).

• Journal of Welding and Joining
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• 제20권4호
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• pp.538-543
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• 2002

M/S TB(Mash Seam Tailored Blank) is a production method for blanks by welding together blanks of different material, thickness and coating, and is an attractive method for manufacturing car body because it makes parts lighter and can save the cost and time to manufacture. However, there have not been quantified criteria to evaluate the quality of TB weld. This study introduced FHR (failure height ratio) in order to assess formability or/and weldability of the M/S welds and the applicability of FHR was confirmed by actual auto body forming and FLD tests. Furthermore, a new parameter, HN(heat number) based on the heat input of "$Q=I^2Rt$" was proposed and assessed. It was found that the concept of HN could be utilized to evaluate the soundness of M/S welds without any destructive tests.ive tests.

• 전기학회논문지
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• 제61권6호
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• pp.910-915
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• 2012

In this paper we propose multi-grounded neutral design method which was considered of transferred transient overvoltage when line to neutral fault occurs. Specially, In order to confirm the actual transient overvoltage magnitude which occurs on neutral line, we considered some screening(shielding) effects. The screening coefficient was deducted from field test results and calculation in a distribution line which is identical with an actual power line. The purpose of this paper is to attempt to suggest the guidance for grounding skystem design considering limitation of overvoltage for LV side in IEC 61936. The result is based on EMTP simulation and real field faults situation in distribution lines.

• 한국생산제조학회지
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• 제18권4호
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• pp.362-368
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• 2009

In general, circuit board assemblies experience various mechanical loadings during assembly and in actual use. The repeated cyclic bending can cause electrical failures due to circuit board cracks, solder interconnects cracks, and the component cracks. In this paper, we report on the failure characteristics of semiconductor chips under the repeated cyclic bending. We first describe a new 4-point bending tester, which is developed according to JEDEC standard No. 22B113. The performance of the tester is then estimated through actual experiments. Test results reveal that the cracks first occur on the outer balls around 20,000 cycles and gradually propagate to the inner balls where cracks are found around 70,000 cycles.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.243-248
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• 2008

The purpose of this study is to introduce alternative cost-effectiveness analysis method of DSM investment programs. This alternative method is Value Test method which consider the effects of DSM investment program on customer value. And this method was applied for actual DSM investment program in natural gas domain. By utilize this method to evaluate cost-effectiveness of DSM investment programs, it is expected to make right decision to enforce and complement those programs.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.337-342
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• 2002

A new apparatus called the EFA (Erosion Function Apparatus) has been built and tested to measure the erodibility of fine-grained soils. The EFA is a simple test to predict the erosion rate of fine-grained soils along with the corresponding velocity and shear stress. In addition, it is advantageous in predicting the scour rate for actual soil samples from bridge sites. The plot of erosion rate versus shear stress is the result of an EFA test. It Indicates the critical shear stress at which erosion starts and the rate of erosion beyond that shear stress. In order to measure the erodibilities of various soils, 14 Shelby Tube soil samples are collected from the actual bridge sites and tested using the EFA. The results of the EFA tests which are the relationships between erosion rates and shear stresses are presented in this paper and research continues to develop the correlation between the erosion function and the soil properties.

• 대한전기학회논문지:전력기술부문A
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• 제55권11호
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• pp.468-475
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• 2006

This paper reviews the energy characteristics of oil filled cables in transient state such as grounding fault and lightning surge. Artificial grounding fault test was firstly performed in 2003 for the analysis of arc voltage and breakdown energy according to the fault current. In this paper, energy of OF cable is variously analysed at joint box based on the actual test. Then more various conditions such as installation types, section lengths and CCPU(Cable Covering Protection Unit) connection types are applied for the simulation using EMTP when the single line to ground fault and direct lightning stroke are occurred on actual underground power cable systems and combined power cable systems, respectively. Finally, the energy by the length of crossbonded lead and grounding lead as well as fault lasting time is also calculated using EMTP simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.479-481
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• 2007

This paper presented a actual conditions on a false-tripping of ELB(Earth Leakage Breakers) and an assessment of the harmonics due to non-linear electronic equipment such as personal computers, rectifier, electric furnace and test equipments in plant installations. Actual conditions on a failure of ELB were surveyed and analyzed by making up a question to safety managers of plant installations. Also, power quality measurements such as harmonic currents, voltage and current waveform and current imbalance were made at various plant installations where nuisance tripping of ELB is often occurred. The results of this study can be used in making decisions regarding cause of ELB trip and operating and tripping characteristics test of ELB when subjected to distorted current waveform.