• 대한기계학회논문집A
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• 제29권9호
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• pp.1270-1275
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• 2005

Rolling process to fabricate a strip with even thickness is significant to enhance the quality of the strip. The thickness of a strip can be effectively controlled by pair-cross mills. However, pair-cross mill generates thrust in the axial direction of roller and causes skewness, deflection, twist and even accidental roll chock failure. Therefore, accurate estimation of the thrust of the pair-cross mill during rolling process is necessary to monitor the failure of roll and the quality of products. An empirical equation given by Mitsubishi Heavy Industry (MHI) is hitherto employed, where the thrust is expressed in terms of rolling force, reduction ratio and crossed angle. However it turns out that the MHI empirical equation provides somehow inaccurate and unsuitable thrust in practical rolling processes. Moreover, we learn that three parameters involved in MHI equation are coupled each other. In this paper, axiomatic design principle is employed to select appropriate parameters involved in approximate equation in order to make parameters uncoupled. A quadratic equation using response surface method with new parameters is suggested. The accuracy of the approximate model is examined by comparing with real experimental data.

• 품질경영학회지
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• 제41권2호
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• pp.301-322
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• 2013

Purpose: This study aims to determine the needs of customers who use railroads as a mode of transportation and propose customer-oriented improvements in railroad technology by making connections between customer needs and railroad technology. Methods: We primarily used two methods for this study, AHP and QFD. First, AHP was used to evaluate the relative importance among the different components of railroad technology. Second, the QFD was applied to make a link between customer needs and railroad technology. Results: Railroad technology is largely divided into development, maintenance, and support. Empirical results showed the following improvement priorities in development, vehicle, system, line, signal/communication, power, and structure, in maintenance, vehicle, signal/communication, line, process, power, and structure, and in support, safety/precaution, management, environmental energy, operations/logistics, and station. Conclusion: Recognizing limitations in measuring the level of railroad technology when using the existing 'Technology Growth Model,' we used AHP and QFD to explore improvement directions for customer-oriented railroad technology. By offering customer-oriented services based on this study, railroad service providers will be able to acquire competitive advantage in the market.

• 디지털융복합연구
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• 제9권1호
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• pp.201-212
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• 2011

본 연구는 최근의 디지털정치 관련 국내의 연구경향을 파악하기 위한 목적으로 진행되었다. 분석 대상은 실증분석을 시도한 2004년 이후 박사학위논문을 대상으로 메타분석을 실시하였다. 이에 따라 첫째, 디지털정치에 대한 연구경향을 정치참여, 정치과정, 정치광고 및 선거캠페인으로 구분하여 이에 대한 연구자의 정의 실증분석에 사용된 분석의 툴, 그리고 그 결과를 체계적으로 검토하였다. 둘째, 해당 주제의 연구모형과 분석단위, 개념 및 개념의 구성요소를 정리하여 후속 연구의 기초자료를 제공하였다. 본 연구의 결과, 디지털정치가 실세 시민의 정치석 삶에 구체적으로 작동되고 있다는 점을 확인하였으며, 최근의 연구는 과거의 규범적 연구를 넘어 디지털 정치연구의 작동 원리와 현상, 다양한 변수를 구체적으로 규명함으로써 연구의 엄밀성과 축적성을 도모하고 있음을 알 수 있었다. 다만, 보다 다양한 변수 및 지표개발이 요구되며, 정당을 포함한 정치 단체와 소셜 미디어 서비스간 권력관계와 영향력 관계 등 연구주제의 다양화가 요청되고 있다.

• 경영과학
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• 제24권2호
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• pp.157-176
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• 2007

Fuzzy cognitive map(FCM) has long been used as an effective way of constructing the human's decision making process explicitly. By taking advantage of this feature, FCM has been extensively used in providing what-if solutions to a wide variety of business decision making problems. In contrast, the goal-seeking analysis mechanism by using the FCM is rarely observed in literature, which remains a research void in the fields of FCM. In this sense, this study proposes a new type of the FCM-based goal-seeking analysis which is based on utilizing the genetic algorithm. Its main recipe lies in the fact that the what-if analysis as well as goal-seeking analysis are enabled very effectively by incorporating the genetic algorithm into the FCM-driven inference process. To prove the empirical validity of the proposed approach, valid questionnaires were gathered from a number of experts on software sales, and analyzed statistically. Results showed that the proposed approach is robust and significant.

• 경영과정보연구
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• 제4권
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• pp.469-500
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• 2000

Over the past decades the concept of Third-Party Logistics(TPL) has generated considerable interest in American and European industries. It involves outsourcing logistics activities that have traditionally been performed within an organization. The functions performed by the third-party logistics can encompass the entire logistics process or, more commonly, selected activities with that process. Increasing corporate emphasis on such concepts as reengineering and supply chain management has led many companies to consider the use of such third-party logistics. This study examines the possibility of applying existing American research of the third-party logistics to Korean companies and investigates the criteria for the use of third-party logistics in Korea. To design the model and generate the hypotheses, this study conducted a comprehensive literature survey on the third-party logistics. To test the hypotheses, this study collected data from 229 companies from the public companies in Korea through a questionnaire survey and conducted descriptive analysis, correlation analysis, factor analysis, and multiple regression analysis using the SPSS for Windows Ver. 7.5 package. This study is hoped that it may contribute to the understanding and introducing of the third-party logistics in the fields of the firms. But there were some restrictions that the respondents were not covered all kinds of firms. These and other major findings from this study imply that existing American studies may be applicable the Korean companies and that this study may complement the deficiencies of the existing studies. Thus, the summary of the literature review, the research model and hypotheses, and empirical findings in this study will provide useful ideas for future research and deep insights for successful logistics management.

• 한국정보시스템학회지:정보시스템연구
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• 제27권4호
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• pp.189-202
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• 2018

Purpose As job market squeezes and more institutions have been requiring NCS(National Competency Standards) based recruitments, the importance of NCS has been growing. Among the 10 domains of NCS, the most relevant one with MIS(Management Information Systems) field is 'information ability', which is becoming more important with the advent of the fourth industrial revolution era. The purpose of this study is to investigate the effect of college students' information ability on their career preparation behavior. Design/methodology/approach In this study, we set up a process model to comprehend the effect of college students' information ability on career preparation behavior based on social cognitive career theory. For research model testing, 561 questionnaires were used for empirical analysis through structural equations modeling. Findings Empirical analysis showed that information ability positively influenced college students' career preparation behaviors for employment. In addition, this study presented a process model explaining the effect of information capability on career preparation behavior. In order to strengthen the information ability of college students, not only university-level efforts, but also MIS discipline efforts should be accompanied. Other academic and practical implications are discussed.

• East Asian mathematical journal
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• 제37권4호
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• pp.443-460
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• 2021

This study analyzes the characteristics of elementary math gifted classes through the development and application of teaching and learning materials. We used the guided reinvention methods including quasi-experiential perspectives. To this end, the applicability of Lakatos' quasi-empirical mathematical philosophy in elementary mathematics was examined, and the criteria for the development of teaching and learning materials for gifted students were presented, and then this study was conducted in this theoretical background. The subjects of the study were 21 elementary students at P University's Institute of Science and Gifted Education, and non-face-to-face real-time classes were conducted. Classes were divided into introduction, deployment1, deployment2, organization stages, and in each stage, small group cooperative learning was conducted based on group activities, and in this process, the characteristics of elementary mathematics gifted were analyzed. As a result of the study, elementary mathematics gifted students did not clearly present the essence of justification in the addition algorithm of fractions, but presented various interpretations of 'wrong' mathematics. They also showed their ingenuity in the process of spontaneously developing 'wrong' mathematics. On the other hand, by taking interest in new mathematics starting from 'wrong' mathematics, negative perceptions about it could be improved positively. It is expected that the development of teaching and learning materials dealing with various and original topics for the gifted students in elementary school will proceed through follow-up research.

• 한국해양공학회지
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• 제36권4호
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• pp.251-269
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• 2022

The process-based XBeach model has numerous empirical parameters because of insufficient understanding of hydrodynamics and sediment transport on the nearshore; hence, it is necessary to calibrate parameters to apply to various study areas and wave conditions. Therefore, the calibration process of parameters is essential for the improvement of model performance. Generally, the trial-and-error method is widely used; however, this method is passive and limited to various and comprehensive parameter ranges. In this study, the Generalized Likelihood Uncertainty Estimation (GLUE) method was used to estimate the optimal range of three parameters (gamma, facua, and gamma2) using morphological field data collected in Maengbang beach during the four typhoons that struck from September to October 2019. The model performance and optimal range of empirical parameters were evaluated using Brier Skill Score (BSS) along with the baseline profiles, sensitivity, and likelihood density analysis of BSS in the GLUE tools. Accordingly, the optimal parameter combinations were derived when facua was less than 0.15 and simulated well the shifting shape, from crescentic sand bar to alongshore uniform sand bars in the surf zone of Maengbang beach after storm impact. However, the erosion and accretion patterns nearby in the surf zone and shoreline remain challenges in the XBeach model.

• 한국자기학회지
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• 제9권4호
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• pp.217-222
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• 1999

공업적으로 세라믹공정에 많이 사용되고 있는 습식 볼밀링으로 NiCuZn ferrite 제조과정 중 혼입되는 불순물의 양을 조사 검토하였다. NiO, CuO, ZnO 및 Fe2O3의 화학조성을 변화시켜 25 vol%로 혼합하고 스테인레스 볼밀로 습식방법을 이용하여 18시간 분쇄한 후 건조시켜 $700^{\circ}C$ 3시간 하소하였다. 하소한 분말을 다시 상기와 같은 방법으로 65시간 스테인레스 볼밀로 최종 분쇄하여 저온소결용 NiCuZn ferrite(NCZF) 소재를 제조하였다. NCZF 연자성 소재를 만드는 동안 혼합 분쇄과정에서 혼입되는 불순물의 스테인레스 스틸의 양은 산화철 및 산화니켈의 함량에 많은 영향을 받았고, 하소 후의 분쇄과정에서 혼입되는 불순물의 양은 결정화된 정도에 따라 영향을 받았다. 전자기적 특성을 갖는 화학조성의 조절을 위하여, 출발원료의 함량에 따라 분쇄과정에서 혼입되는 스테인레스 스틸의 함량을 도출하는 형식을 유도하였다.

• 대한기계학회논문집B
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• 제41권6호
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• pp.415-421
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• 2017

환경규제의 강화에 따라 수처리 비용이 증가하는 추세이므로 폭기공정의 에너지 이용효율을 제고할 수 있는 소요동력에 대한 보다 정량적인 연구가 필요하다. 본 논문은 폭기공정의 물질전달 특성을 규명하기 위해 물질전달 계수와 기체 포집율 및 소요동력에 대한 상관관계식을 제시하였다. 소요동력이 커지면 기체 포집율은 감소하고 레이놀드 수는 증가하며, 혼합유동 선단 도달거리와 확산도가 증대되므로 물질전달 계수는 증가하였다. 물질전달 계수와 기체 포집율 및 소요동력의 상관관계 규명을 위해 제시한 실험식은 최대 약 ${\pm}10%$의 오차 범위에서 실험결과와 일치하였다.