• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.221-227
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• 2016

The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.1924-1934
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• 2009

Mixture phenomena are present in the overall culture due to internationalization in a modern society. A unique feel is required in materials due to the increasing demand for knit wear and there is a need for a strategic plan to achieve this. This study analyzed the appearance frequency and expressive characteristics of mixture phenomena based on selected data from collections related to the mixture phenomena trends in modern women's fashion from 2000 to 2008. Among the mixture phenomena, the mixture of the high and low class cultures had the highest frequency of occurrence and was expressed most often since the expansion of design areas was due to vague high and low concepts. The mixture of sexes showed the sharing of knit wear trends between the sexes with the pursuit of functionality. The mixture of styles showed a tendency to increase since the traditional form was transformed into a mixture of typical styles. The mixture of spaces showed a mixture of old and traditional knit wear patterns from Northern Europe and modern elements. The mixture of other materials showed the partial preceding mixture and the decorative materials that existed beyond it. The mixture of functions refers to the used characteristics of the two items. Imagination will grow and increase the possibility of expressions with the mixture of the other areas.

• Archives of design research
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• v.18 no.2 s.60
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• pp.27-36
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• 2005

Illustrations in advertisement uses various social and cultural codes to stimulate the desire to buy in consumers in the first place, since this is an economic phenomenon orchestrated to sell a product. Hence, factors outside the product per se, such as tradition, social issues and class consciousness are introduced. Especially, in modern advertisement a strategy is adopted to differentiate standard products produced by mass production. In order to do so, such factors as mentioned above become as important as physical characteristics of the product per se and its usage value. As a result, phrases or images used for advertisement can have independent influences on the society irrespective of the sales effects on the product. In this respect, it is fair to state that advertisement reflects the phases and consciousness of a given period as a cultural phenomenon. Therefore, based on the premise of characteristics and roles attributed to the advertisement, this thesis proposes to make a comparative study on the images of women in commercial advertisement in Korea during Japanese Imperialism and China during Cultural Colonial period dating from 1900 to 1945. The starting point of this research will cover the period of foreign trade and Japanese Imperialism in Korea and interference of Western Power in China. It will also investigate on the birth of Korean advertisement by Japanese Imperialists and Chinese modern advertisement along with the modernization of Shanghai. Then, I propose to present the illustrations of women in advertisements based on comparative study of their characteristics and expressions as observed in several case studies both in Korea and China. Connotative meanings in such advertisement will be investigated in the context of political, economic and cultural dominance.

• 대한공업교육학회지
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• v.36 no.2
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• pp.1-23
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• 2011

The purpose of the study was to investigate the generality and applicability of Team-Based Learning model in a technical high school, based on the interviews with students and a teacher. Team-Based Learning model seems to be an effective way in improving the performance of groups as well as the individualized learning and team interaction. We applied a formative research method and identified the strengths of the model including learners' motivation and interests, learner-centered learning, self-efficacy through learning in advance, and concept acquisition from the repetitive learning process. However, we also found the weakness of the model including impracticality of instructional design, a lack of field-oriented problem banks, and needs for identifying learner characteristics and role in instruction. Finally, we analyzed the implications for the Team-Based Learning in the technical high schools in light of team formation, discussion types, active participation, and learners' prior knowledge and attitude, and pre-determined instructional design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.114-123
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• 2018

This paper concerns a design and learning method of softmax function neural networks based on K-means clustering. The partial discharge data Information is preliminarily processed through simulation using an Epoxy Mica Coupling sensor and an internal Phase Resolved Partial Discharge Analysis algorithm. The obtained information is processed according to the characteristics of the pattern using a Motor Insulation Monitoring System program. At this time, the processed data are total 4 types that void discharge, corona discharge, surface discharge and slot discharge. The partial discharge data with high dimensional input variables are secondarily processed by principal component analysis method and reduced with keeping the characteristics of pattern as low dimensional input variables. And therefore, the pattern classifier processing speed exhibits improved effects. In addition, in the process of extracting the partial discharge data through the MIMS program, the magnitude of amplitude is divided into the maximum value and the average value, and two pattern characteristics are set and compared and analyzed. In the first half of the proposed partial discharge pattern classifier, the input and hidden layers are classified by using the K-means clustering method and the output of the hidden layer is obtained. In the latter part, the cross entropy error function is used for parameter learning between the hidden layer and the output layer. The final output layer is output as a normalized probability value between 0 and 1 using the softmax function. The advantage of using the softmax function is that it allows access and application of multiple class problems and stochastic interpretation. First of all, there is an advantage that one output value affects the remaining output value and its accompanying learning is accelerated. Also, to solve the overfitting problem, L2-normalization is applied. To prove the superiority of the proposed pattern classifier, we compare and analyze the classification rate with conventional radial basis function neural networks.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.309-321
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• 2007

Since the first diesel passenger car hit the local road in late 2005, the share of diesel cars is growing significantly; possibly up to the level as in the western Europe. In this study, the effects of introduction of diesel passenger cars on the ventilation rate and facility capacity are analyzed for the three individual cases with different basic exhaust rate based on the vehicle age, the vehicle class percentage and the smoke exhaust rate. The target tunnel for this comparative study is a typical 2 km-long 2-lane highway tunnel. Case 1 assuming the current local design standards and the diesel vehicles comprising 40% of the total passenger cars on the road required more ventilation rate and facility capacity than in the case only with the current standards. Case 2 which is the real tunnel currently in the designing stage taking into account the vehicle age but ignoring the diesel vehicle ratio, and Case 3 on the contrary considering the both factors show similar level of ventilation characteristics as EURO-3 emission regulation. Application of the emission standard set by the Ministry of Environment for newly manufactured vehicles in the current local tunnel design standard indicates higher requirements than for EURO-2 regulation, whereas the emission standard came into effect in 2006 results in the ventilation characteristics similar to EURO-4. This study aims at providing fundamental information for assessing the basic emission rate and determining the optimal ventilation rate and facility capacity considering the growing percentage of diesel cars and gradually decreasing level of smoke emission forced by the relevant laws.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.262-272
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• 2005

This study was undertaken to obtain design concentrations for the natural system treating stream water flowing into estuarine lake(Sapgyo). This lake has three major, so called, national-class streams: one is Gokgyo flowing through two medium-size municipal areas and the others are Muhan and Sapgyo placed in mostly rural area nested with some small towns. The results of three year's investigation showed big changes in water quality during the period between dry and wet seasons. Nitrogen concentration usually decreases as the flow rate increases. The change of phosphorus concentration in Gokgyo was the same pattern as nitrogen, but in other two streams it was inversely related with flow rates. This is probably due to the chemical property of the particles washed out from the different stream basins during wet season. It was found that about 40 to 60% of the total nitrogen are in soluble form and on average, 35% of the total phosphorus consists of dissolved-P. Representative concentration of these streams has to be separately determined based on dry and wet season. TDS and SS could be indicating parameters useful to depict and characterize a change of water quality with respect to flow rate because their measurement is easy and also includes a small analytical error. TDS values measured during dry season are related with high nitrogen concentration while during wet season, SS values effectively reflect a high concentration of phosphorus. For design purpose, cumulative concentration distribution graph presented in this paper can be directly or indirectly applied to other streams through a brief comparative and verificative study.

• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1418-1432
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• 1997

Most general content_based image retrieval techniques use color and texture as retrieval indices. In color techniques, color histogram and color pair based color retrieval techniques suffer from a lack of spatial information and text. And This paper describes the design and implementation of content_based image retrieval system using color space and keywords. The preprocessor for image retrieval has used the coordinate system of the existing HSI(Hue, Saturation, Intensity) and preformed to split One image into chromatic region and achromatic region respectively, It is necessary to normalize the size of image for 200*N or N*200 and to convert true colors into 256 color. Two color histograms for background and object are used in order to decide on color selection in the color space. Spatial information is obtained using a maximum entropy discretization. It is possible to choose the class, color, shape, location and size of image by using keyword. An input color is limited by 15 kinds keyword of chromatic and achromatic colors of the Korea Industrial Standards. Image retrieval method is used as the key of retrieval properties in the similarity. The weight values of color space ${\alpha}(%)and\;keyword\;{\beta}(%)$ can be chosen by the user in inputting the query words, controlling the values according to the properties of image_contents. The result of retrieval in the test using extracted feature such as color space and keyword to the query image are lower that those of weight value. In the case of weight value, the average of te measuring parameters shows approximate Precision(0.858), Recall(0.936), RT(1), MT(0). The above results have proved higher retrieval effects than the content_based image retrieval by using color space of keywords.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.93-102
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• 2018

This paper reports a Surge Protective Device (SPD) that is used to protect an automatic metering interface (AMI) power supplies of communication equipment on a low-voltage distribution system from a lightning current. The surge protective device (SPD) can be classified as one-port SPDs and two-port SPDs with decoupling elements depending on the connection type. The protection of internal systems against the lightning current may require a systematic approach consisting of coordinated SPDs. To deal with this, the definition of a lightning protection zone (LPZ) was studied and interpreted through a theoretical review. Because the lightning current resulting from a lightning surge is considerably high, there is limited protection from one SPD; therefore, coordinated cascaded MOV-based SPDs are installed to solve this problem. Regarding the power grid mentioned in this paper, a class II SPD for the low-voltage distribution system installed on the border of LPZ1 and LPZ2, which establish a protection coordination with the Arrester (LA, SA) that corresponds to the LPZO installed on the MOF stage connected to one system were designed to protect various communication (control) equipment, including the automatic meter reading system inside the branch-type electric supply panel of a building, not the incoming side of one system. In addition, performance-related tests were done by a comparison with the existing method through testing, and the optimal design was achieved for the 1-port SPD that uses a series connection and can bleed load current without any decoupling element.

• The Journal of Sustainable Design and Educational Environment Research
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• v.15 no.2
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• pp.1-12
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• 2016

This study was conducted to extract the student-centered experiential safety education activities in order to establish safety-experience-education-facilities based on "School safety education 7 standards" announced by the Ministry of Education in 2015. For this purpose, we established the concept of safety-experience-education-facilities, and conducted surveys twice targeting experts of each 7 fields based on the learned results of 758 sessions through "School safety education 7 standards". First, through the surveys, it was organized by 150 sessions out of 758 education class that extracted from safety-education-program sessions on experts, conducted a second expert survey for the validation of selected educational programs in Delphi format, the result of 5 sessions of the program is deleted, and 145 sessions was surveyed to be maintained. It was ascertained that 145 sessions of education program, 21 sessions of life safety area, 22 sessions of traffic safety area, 18 sessions of violence and personal safety area, 5 sessions of drugs and cyber addiction area, 36 sessions of disaster safety area, 10 sessions of occupation safety area, 33 sessions of first-aid area, is the experiential safety education activities that have to be applied to the safety-experience-education-facilities.