• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.669-678
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• 1994

This paper presents a new data predistortion technique with memory to compensate for the nonlinearities of high-power amplifiers (HPA`s) in digital radio systems employing QAM signal formats. In contrast with the conventional data predistortion technique which is designed to reduce nonlinearity of memoryless HPA`s, the proposed technique in this paper compensates not only for nonlinear warping of the signal constellation but also for clustering of the signal points caused by transmitter pulse sharping filter with memory. A practical implementation method which can reduce the size of memory at the predistortion stage is described by utilizing symmetry of QAM constellation format and Modulo-4 operation.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1595-1597
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• 2003

This paper presents the deposition of ${\mu}c$-Si:H thin-film and fabrication of a solar cell by VHF-PECVD method. The ${\mu}c$-Si:H thin films and pin-type solar cells are fabricated using multi-chamber cluster tool system. A 7.4% conversion efficiency was achieved from ${\mu}c$-Si:H thin film solar cells with total thickness less than $5{\mu}m$. The physical characteristic was measured by Raman spectroscopy, Solar cell characteristic was measured under AM1.5 illumination.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.1
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• pp.65-87
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• 2016

The purpose of this study is to examine Korean journals related to science education in order to analyze research trends into Nature of science in Korea. The subject of the study is the level of Korean Citation Index (KCI-listed, KCI listing candidates), that can be searched by the key phrase, "Nature of science" in Korean language through the RISS service. In this study, the Descriptive Statistical Analysis Method is utilized to discover the number of research articles, classifying them by year and by journal. Also, the Sementic Network Analysis was conducted to Word Cloud Analysis the frequency of key words, Centrality Analysis, co-occurrence and Cluster Dendrogram Analysis throughout a variety of research articles. The results show that 91 research papers were published in 25 journals from 1991 to 2015. Specifically, the 2 major journals published more than 50% of the total papers. In relation to research fields., In addition, key phrases, such as 'Analysis', 'recognition', 'lessons', 'science textbook', 'History of Science' and 'influence' are the most frequently used among the research studies. Finally, there are small language networks that appear concurrently as below: [Nature of science - high school student - recognize], [Explicit - lesson - effect], [elementary school - science textbook - analysis]. Research topic have been gradually diversified. However, many studies still put their focus on analysis and research aspects, and there have been little research on the Teaching and learning methods.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.3_4
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• pp.441-451
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• 2003

The purpose of this study was to find out evaluative criteria of cyber store toward shopping orientation, purchasing experience and demographic factors of consumers to visit cyber store. This study surveyed consumers who have an experience of using cyber store and judgment sampling was used. The respondents were 240 men and women living in the metropolitan area of Seoul and Gyeonggi province. Research method was measured by clothing shopping orientation (utilitarian and hedonic factors), cyber store evaluation criteria (convenience, quality & trust and product character factors), purchasing experience(existent and nonexistent) and demographic factors. For data analysis, descriptive statistics, factor analysis, cluster analysis, ANOVA, t-test, Duncan test, and reliability analysis were conducted. The results were as follows: 1. Evaluative criteria of cyber store were considered importantly in order of possibility of exchange and refund, stability of personal information security, substance of quality degree of product and service and store. 2. Among shopping orientation groups, there were significant differences in all evaluative criteria of cyber store: convenience, quality & trust and product character of store. 3. Among groups toward existence and nonexistence in a purchasing experience, there were significant differences in convenience and quality & trust of store. 4. Among Demographic factors(gender, job, education and income) there were significant differences in convenience and quality & trust of store.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.8
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• pp.1075-1094
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• 2013

This study analyzed the lower body type of women aged 20 to 30 to understand their respective characteristics. The research method was restricted to the use of direct measurements data and 3D measurements data of the Sixth Size Korea. Factor analysis, cluster analysis, ANOVA, Duncan's test, discriminant analysis, t-test, and ${\chi}^2$-test were performed for the statistical analysis of the data using SPSS Win 20.0 program. The results of this study are as follows. Lower body type based on 3D measurements were classified into 3 types (obese lower body, long lower body, and small lower body). Lower body type based on direct measurements were classified into 3 types (obese lower body, thick and long lower body, and small lower body). Lower body type based on the direct measurement of sitting pose were classified into 3 types (obese lower body, long and thin lower body, and short lower body). The age differences in the lower body types could be analyzed by an evaluation of the 3D simulation of the lower body.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.193-194
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• 2015

본 연구는 요인분석을 통해 노인 보행자 사고 유형을 대표할 수 있는 성분 값을 계산하고 군집분석을 실시하여 노인 보행자 사고 취약 지역을 선정하는 모델을 확인하였다. 기존 노인보행자 사고에 관한 연구는 보행 환경 분석 및 노인보행자 사고 특성을 확인한 뒤, 제도적, 물리적 환경 개선 등에 대한 정책 제언의 형식으로 진행되었다. 이러한 연구는 실질적으로 노인 보행자 특성을 분석하여 사고를 감소시키는 연구가 아닌, 일반적으로 알려진 사실이나 해외 사례를 들어 노인 보행자 사고의 현 실태에 대해 어느 정도 환기만 시켜주는 역할로 그쳤다. 이러한 점에서 군집분석을 통한 노인 보행자 사고 취약지역 선정은 노인 보행자 사고 특성의 비교를 명확하게 할 수 있도록 새로운 기준을 제시하였다. 이에 기존의 방법론에서 벗어나 실질적으로 노인 보행자 사고 방지 대책이 시급한 지역을 선정하였고, 노인 보행자 사고에 관해 활발히 연구 시킬 것이라 예상한다. 군집분석을 사용하는 핵심은 사망자 수와 사망률이 상대적으로 동시에 높은 군집을 선정할 수 있고 지역 특성 비교를 통해 향후 노인 보행자 사고에 관한 추가 연구가 가능할 것으로 기대한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.1-7
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• 2005

In vehicle door system, weatherstrip seals protect passengers form noise, dust, rain and wind out of the vehicle. The higher efficient a weatherstrip is, the more durable it is in contact between the door and body frame. In this study, nonlinear finite element(FE) analysis is performed to obtain cauchy-stresses, displacements and reaction forces of the weatherstrip. Mechanical properties of the weatherstrip is obtained by uniaxial tension test. The MARC which is a commercial software for the nonlinear analysis of a flexible FE model is used. Twenty-one cases of the FE model are developed by using Ogden-foam formulation. In the results of nonlinear FE analysis, the most valuable deformation of the weatherstrip occurred when displacement control value reaches 7.2mm. Severe deformation is observed as the displacement control value become more increased. When the weatherstrip is designed, it would be considered that the displacement value of the weatherstrip has to be less than 7.2mm.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.90-103
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• 1998

The purposes of this study are to estimate the economic value and reasonable entrance fee of the Yeido Park, which is under construction in Seoul, by conduct the face-to-face interview. A total of 645 daults were selected by two stage cluster sampling. The senario was designed to meet the requirements for doubgle-bounded dichotomous choice CVM, and distributed with the photograph to epict and compare the current and suggested conditions. A donation vehicle and entrance fee were utilized to find the possibility of strategic behaviors and protest zero, and to make the data estimatable tfor interval censored survival analysis. Date was calibrated by the survival analysis to eleminate the 'fat-tail problem'. Weibull distribution was assumed as a baseline distrubution. The mean WTP of donation and entrance fee was ￦5,281 and ￦783, respectively. The economic value of this park was determined by aggregating the mean value, giving a total WTP for the population of ￦36,861,645,000. This economic value was composed with the use value and existence value. The calibrationi of the Weibull proportional hazard model showed that nearness to the park, age, intention to isit the park, and educational attainment were significant independent variable to influence an amount of donation.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.1-16
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• 1995

This study was carried out to suggest method which can be used to improve competitive power of theme parks. The characteristics of Hybrid Conjoint Analysis were described and its usefulness for identification of specific types of service theme parks have to provide was tested "Lotte World, " "Seoul land," and "farmland" were selected as study areas, and .7 attributes with 3 levels were utilized for analyses. Master design with 81 profiles was constructed to meet the requirement of ′Compromise Plan 1,′and data was collected by in-personal interviews on the study areas. Respondents were grouped by cluster analysis, and their characteristics were analyzed by discriminant analysis. Then, part-worth of each attribute . was estimated by stagewise estimation model Calibrated model of each group did not show part-worths of attributes clearly because both main effects and 2-way interaction effects were included in the models. Therefore, calibrated models′ coefficients were used to calculate utilities of all possible combinations of attributes levels. The results showed that managers of theme parks have several options for providing a new service: the combination of attribute levels with the highest utility is they however, they can choose the other combinations with next highest utlities is they can not afford it. Several suggestions were described to cope with the problems when Hybrid Conjoint Analysis is applied to landscape architectural study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1599-1607
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• 2015

Recently, researches have been developing efficient techniques for accessing, querying, and managing XML documents which are frequently used in the Internet. In this paper, we propose a parent-child matrix to cluster XML documents efficiently. A parent-child matrix analyzes both the content and structural features of an XML document. Each cell of a parent-child matrix has either the value of a node in an XML tree or the value of a child node, where a parent-child relationship exists in the XML tree. Then, the similarity between two XML documents can be measured by the similarity between two corresponding parent-child matrices. The experiment shows that our proposed method has good performance.