• International Journal of Railway
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• v.5 no.1
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• pp.1-9
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• 2012

Reliability means that a product maintains its initial quality and performance at a certain period of time (time, distance, cycle etc) under given condition without failure. The given conditions include both environmental condition and operating condition. Environmental condition means a common natural environment such as temperature, humidity, vibration, and working condition means an artificial environment such as voltage, current load, place for installment, and hours of use, which occurs during the life of the product. In the field of railway vehicles, it is mandatory to use a part with the proved reliability as the extension of the life of vehicle become highly necessary. But the reliable assessment method for the reliability of the part is insufficient. If the reliability of the railway vehicle parts could be assessed by using the field data, the reliability of the entire system could also be evaluated reliably. In this study, life span of micro-switch for master controller is analyzed and prediction is performed based on its field data given by an operator considering the special circumstances of railway vehicles such as the operation of a large number of trains on the same line.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.65-75
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• 2003

In these days, public transportation has become important because of serious traffic congestion. But. there are few researches in public transportation compared with researches in auto. Accordingly, the purpose of paper is development of transit assignment model, which considers features of public transportation, time table, transfer capacity of vehicle, common line, etc. The transit assignment model developed in this paper is composed of two parts. One part is search for optimum path, the other part is network loading. A Genetic algorithm has been developed in order to search for alternative shortest path set. After the shortest paths have been obtained in the genetic algorithm, Logit-base stochastic loading model has been used to obtain the assigned volumes.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.45-53
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• 2013

In this paper, we analyze the failure mechanism of the washer pump to find what is the failure cause in the road environment. The statistics show the field common failure mode is inner corrosion. The failure mechanism is assumed that the inner part of washer pump is corroded due to inflow of moisture through vent hole. To prevent the failure, we can think a method that is covering the vent hole. In general, the vent hole is designed to play an important role in an automobile parts. So, we need to prove the vent hole is not necessary. The first purpose of this paper is to make sure that the vent hole does not affect the durability of washer pump using the analysis of operating condition. The second purpose is to compare the durability properties if the vent hole is covered.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.389-394
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• 2008

Nowadays Plate Heat Exchanger (PHE) is widely used in different industries such as chemical, food and pharmaceutical process and refrigeration due to the efficient heat transfer performance, extreme compact design and efficient use of the construction material. In present work, PHE is applied in the fresh water generator system. Fresh water generators or desalinators are installed in ship to convert seawater to fresh water using heat from engines. PHE is an important part of a condensing or evaporating system. Among many of factors which should be concentrated on, the heat transfer and pressure drop is most important parts during sizing and rating the performance of PHE. Flow maldistribution is common but it will significantly reduce the heat exchanger performance. In this paper provide a overview of PHE cover basic of theory and conduct a numerical approach for flow distribution in plate channel. An experimental study on the performance of fresh water generator system which developed by plate heat exchanger will presented in future research. Thus, extensive experiment and analysis is required to study the thermal and fluid flow characteristics of PHE.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.263-268
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• 2015

Malware variations could be defined as malicious executable files that have similar functions but different structures. In order to classify the variations, this paper analyzed sequence alignment, the method used in Bioinformatics. This method found common parts of the Malwares' API call information. This method's performance is dependent on the API call information's length; if the length is too long, the performance should be very poor. Therefore we removed the repeated patterns in API call information in order to improve the performance of sequence alignment analysis, before the method was applied. Finally the similarity between malware was analyzed using sequence alignment. The experimental results with the real malware samples were presented.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.1-9
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• 2017

In the industrial field, various type of fuel have been used for product processing facilities. Recent for 10 years, the usage of natural gas (NG) was gradually increased. Because it has many merits; clean fuel, no transportation, storage facility and so on. There are common safety concept that strict explosion protection approaches are needed for facilities where explosive materials such as flammable liquid, vapor and gases exist. But some has an optimistic point of view that the lighter than air gases such as NG disperse rapidly, hence do not form explosion environment upon release into the atmosphere, many parts has a conventional safety point of view that those gases are also inflammable gases, hence can form explosion environment although the extent is limited and present. In this paper, the heating equipments (Hot Oil Heater) was reviewed and some risk management measures were proposed. These measures include hazardous area classification and explosion-proof provisions of electric apparatus, an early gas leak detection and isolation, ventilation system reliability, emergency response plan and training and so on. This study calculates Hazardous Area Classification using the hypothetical volume in the KS C IEC code.

• English Language & Literature Teaching
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• v.16 no.3
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• pp.339-363
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• 2010

The purpose of this paper is to investigate how the English classes in secondary schools in Korea are in terms of communicative nature. After literature study, COLT parts A and B were used to analyze three kinds of English classes: a common class type taught by a school teacher who had won 1st prize at TEE contest, a team teaching class taught by NNS and NS, and a model class taught by a pre-service English teacher. Their communicative English classes were videotaped and transcribed for analysis by COLT. The results of the study revealed that students participated in the classes mostly as a unit and, therefore, did not get many meaningful chances to speak English. Second, creative language-use opportunities were barely found during classes. Third, the group work seemed to be prepared before the class, not to be done during the class. Therefore it is likely to be learned from memorization rather than meaningful communication. These results suggest English classes in schools be more communicatively oriented for successful English learning. Further study should be conducted in order to make English classes more communicative to help students communicate their genuine messages in English and to help teachers teach English efficiently.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.83-90
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• 2012

Porcine rotaviruses are the most common causes of viral gastroenteritis in piglets around the world. The major G genotypes of porcine rotaviruses causing diarrhea were G4, G5 and G11 genotypes. Recently, G9 genotype rotaviruses were problemed at swine farms and frequently recognized from diarrheic piglets. In this study, a porcine rotavirus (PoRV-1) was isolated from piglet showing diarrhea using MA104 cells and confirmed as rotavirus by electron microscopy, genomic RNA electropherotyping and indirect immunofluorescence antibody tests. The nucleotide sequence of the VP7 gene of PoRV-1 was determined and compared with those of other genotype rotavirus strains from other parts of the world. Also, the nucleotide sequences of VP4, VP6 and NSP4 genes of PoRV-1 were determined and compared with those of other rotavirus strains from other countries. The results showed that the PoRV-1 isolate belonged to the G9 genotype and the P, I and E genotypes of PoRV-1 were P[23], I5 and E1, respectively. The Korean G9 PoRV-1 isolate and its nucleotide sequence data would be usefully used for the development of porcine rotavirus vaccines in near future.

• Research in Community and Public Health Nursing
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• v.18 no.4
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• pp.634-642
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• 2007

Purpose: To investigate subjective symptoms of musculoskeletal disorders in women workers Method: From February to April, 2006, 292 women workers working in 16 companies were surveyed using KOSHA CODE (H-30-2003). Result: Of the workers, 84.0% had at least one musculoskeletal disorder. The mean score of the severity of musculoskeletal disorder symptoms was 7.41 out of 25. As for the prevalence rate by body part, shoulder was the most common and severe body part of musculoskeletal disorders, and significant differences were shown in neck, shoulder, and lower limb according to the type of working. The severity of married workers was significantly higher than that of unmarried ones. Significant difference was shown in the severity of disorders by the type of working and in body parts according to the type of working. Conclusion: The self-reported symptoms of musculoskeletal disorders were very frequent in women workers, but the severity of the symptoms was relatively low, suggesting the early symptoms of disorders. Specifically, given the highly frequent self-reported symptoms in the shoulder part found in married women workers, intensive prevention is recommended. Furthermore, an ergonomic aspect should be concerned to consider physical characteristics of women workers.

• Journal of Korean Elementary Science Education
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• v.24 no.4
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• pp.476-486
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• 2005

The purpose of this study was to compare the biology parts of the elementary school science textbooks of South and North Korea. For this purpose the contents and the names of organism introduced in the textbooks are compared and analyzed. As results of this study, there are a lot of differences in the content and names of organism in the textbooks. Life science in the elemenatry school science of North Korea ($46.9\%$ in 3th grade, $32.7\%$ in 4th grade) is treated more seriously than South Korea. The most part of North Korea textbooks are occupied with the names and values of various organisms, and the using method of them. The common contents of both textbooks are only $8.54\%$ of total contents of elementary school science of South Korea. Also only 39 names of organism are introduced in the both textbooks of South and North Korea. For the science curriculums establishment after unification, it should be the most important efforts to understand the cause of these differences, and to analyze those differences in contents and organisms introduced in the textbooks of South and North Korea.