• 전기학회논문지
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• 제61권7호
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• pp.928-936
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• 2012

The microgrid concept assumes a cluster of loads and microsources operating as a single controllable system that provides a new paradigm for defining the operation of distributed generation. This system can be operated as both grid-connected mode and islanded mode. In other words, the microgrid can be operated to meet their special need; such as economics in steady state and local reliability in islanded mode due to the grid fault. This paper presents the AGC (Automatic Generation Control) method for microgrid with EMS (Energy Management System).

• 한국의류학회지
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• 제44권6호
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• pp.1189-1204
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• 2020

Population aging and longevity have compelled major worldwide consumer markets to focus on senior citizens who exhibit a desire to nurture their appearance and obtain related products such as cosmetics. This trend signals an increasing need for in-depth research on elderly consumers in the color cosmetics market. This study identified the characteristics of seniors in the pre-elderly stage ("new seniors") based on their lifestyle and market segments. It employed online surveys with participants consisting of pre-elderly Korean women born between 1955 and 1963 who reside in the greater Seoul and Gyeonggi area. The study used SPSS 23.0 for factor analysis, reliability verification, cluster analysis, ANOVA, Duncan's test, and cross-analysis. The results show that new seniors could be classified into four groups based on lifestyle: Prime Seniors, Potential Seniors, Rational Seniors, and Slump Seniors. Each group has distinct characteristics. The findings suggest that the senior market requires further segmentation and is no longer a single uniform market. This study also confirms that the lifestyles of the elderly is an instrumental variable for their segmentation.

• 디지털산업정보학회논문지
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• 제17권2호
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• pp.13-20
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• 2021

Placement is a very important step in the VLSI physical design process. It is the problem of placing circuit modules to optimize the circuit performance and reliability of the circuit. It is used at the layout level to find strongly connected components that can be placed together in order to minimize the layout area and propagation delay. The most popular algorithms for circuit placement include the cluster growth, simulated annealing, integer linear programming and genetic algorithm. In this paper we propose a adapted genetic algorithm searching solution space for the placement problem, and then compare it with simulated annealing and genetic algorithm by analyzing the results of each implementation. As a result, it was found that the adaptive genetic algorithm approaches the optimal solution more effectively than the simulated annealing and genetic algorithm.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.35-49
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• 2021

This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with previous data. The anisotropic invariant maps show that the ratio of the streamwise to spanwise velocity fluctuations plays an important role in characterizing the anisotropic nature of the separated shear layer behind the bump in the vicinity of the free surface. The vortex identification discloses a large-scale streamwise vortical structure from the mean velocity field and a cluster of small coherent structures from the instantaneous velocity field, which are responsible for the anisotropic characteristics of the turbulence beneath the free surface.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 춘계학술발표대회
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• pp.593-596
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• 2010

본 논문에서는 선형적인 무선 센서 네트워크에서 지연 및 신뢰성을 고려한 클러스터 기반의 멀티홉 라우팅 알고리즘을 제안한다. 제안한 알고리즘은 선형적인 네트워크 환경에서 전송 지연시간 및 Single Point Of Failure 를 해결하기 위해 짝수 ID 노드일 경우 다음 짝수 ID 노드로 전송하고, 홀수 ID 노드일 경우 다음 ID 노드로 데이터를 전송하는 방법을 사용한다.

• 한국의류학회지
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• 제33권4호
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• pp.586-597
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• 2009

The purpose of this study is to identify the moderating effect of Internet lifestyle among relational benefits effect, customer satisfaction and customer loyalty on the Internet shopping mall. For the study, utilizing the convenient sampling method, the sample of study was composed of female and male adults aged between 20 and 30 living in Seoul metropolitan area who had experienced purchase of fashion products on the web. Of 350 distributed, 311 useful questionnaires were returned. The survey research design was employed with structured questionnaire. For data analysis, descriptive statistics, factor analysis, reliability analysis, cluster analysis and multiple-regression analysis were used. The results of this study are as follows: The results of Internet lifestyle were regarding 4 cluster of Internet lifestyle. 1) information seeking type, 2) shopping maniac type, 3) social gathering type and 4) passive follower type were obtained. The interaction of psychological benefits and the type of Internet lifestyle affected customer satisfaction positively. The interaction of customer satisfaction and Internet lifestyle reinforced customer loyalty. Especially interaction of shopping maniac type among Internet lifestyle types and customer satisfaction affected customer loyalty strongly.

• 한국환경보건학회지
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• 제42권4호
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• pp.280-292
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• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• 대한가정학회지
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• 제35권1호
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• pp.357-372
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• 1997

The purpose of this study was to 1) segment female adolescent consumers into consumer groups displaying different consumer decision-making styles 2) to determine the consumer characteristics(clothing involvement information search store patronage and demographic variables) that related to each consumer segment and 3) to identify the interrelationship between the consumer characteristics. Decision-making styles were measured by 32 seven-point Likert type scales adapted from Sproles & Kendall and Shim & Kot A total of 78 statements dealing with three aspects of consumer characteristics was adapted from previous research. Data were collected from 567 2nd grade female middle and high school students in Seoul via self-administered questionnaires. and were analysed by frequency factor analysis ANOVA cluster analysis χ2 -test and Duncan's multiple range test. The results of this study were as follows: As a results of cluster analysis and ANOVA on seven factors of desion-making styles(1. brand-consiousness 2. novelty/fashion-consciousness 3. recreational/hedonis-tic orientation, 4. impulsive/carelessness, 5. price-consciousness/value-for-money, 6. perfectionism/high quality orientation 7. habitual/brand-royal consciousness) three consumer groups were identified and labeled as puality-oriented/non-utlitarian shoppers price-oriented shoppers and apathetic shoppers. Quality-oriented/non-utilitarian shoppers showed the highest clothing involvement scores of all aspects the highest consumer knowledge/experience most active ongoing information search and prepurchase information search. They preferred department store and franchise store for apparel shopping and considered service/reliability atmosphere variety of goods as important store attributes, Price-oriented shoppers showed prepurchase information search and planned purchase behavior actively. They preferred factory outlet store specialty stre and considered price very important as store attributes. Apathetic shoppers showed the lowest scores of all aspects of clothing involvement and most passive behavior in information search activities except showing the highest planned purchase. They preferred regional markets.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권2호
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• pp.216-220
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• 2008

센서 노드와 싱크 노드로 구성된 센서 네트워크는 모든 센서 노드들이 한정된 에너지를 가지고 운용되기 때문에 네트워크를 오랫동안 유지하여 가용성을 높이기 위한 연구가 다양하게 진행되어 왔다. 대부분의 기존 연구들은 싱크 노드의 이동을 고려하지 않았기 때문에 사람이나 자동차 등에 의해 싱크가 이동성을 가지는 환경에는 부적합하다. 본 논문에서는 그리드 기반의 센서 네트워크에서 이동 싱크와 소스 노드간의 경로 설정에서 요구되는 통신부하(제어 패킷의 수 및 전송 범위)를 줄여 센서 네트워크의 에너지 소모를 줄이고, 경로 설정의 신뢰성을 확보하기 위한 방안을 제안한다. 제안 기법은 다수의 싱크 노드가 존재하는 환경은 물론 큰 규모의 센서 네트워크에서도 성능의 저하가 없어 확장성이 뛰어나며, 기존의 그리드와 클러스터 기반의 프로토콜과 비교하여 약 70% 수준으로 에너지 소모를 줄일 수 있어 센서 네트워크의 생명주기를 늘리고 가용성을 높일 수 있다.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.423-430
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• 2011

본 연구는 부모가 축구선수역할사회화에 미치는 영향을 알아보기 위하여 선행 연구를 기초로 하여, 부모의 운동 참가, 관심, 권유, 태도에 따른 축구선수역할사회화의 관계를 실증적으로 규명하는 것에 주된 목적이 있었다. 이와 같은 연구 목적을 달성하기 위하여 본 연구에서는 현재 대한축구협회에 등록되어 있는 전국의 축구부가 있는 대학교의 축구선수를 모집단으로 설정한 다음 유층집락무선표집법(Stratified Cluster Random Sampling Method)을 이용하여 최종 149명을 선정, 분석하였다. 자료 수집을 위한 도구는<부모가 축구선수역할사회에 미치는 영향>에 관한 질문지로서, 신뢰도를 검증하기 위하여 Cronbach's ${\alpha}$ 방법을 사용하여 검증하였으며 본 질문지의 신뢰도 검증 결과 .8847~.7306으로 나타났다. 본 연구에서 사용한 통계 분석방법은 일원변량분석 및 회귀분석이었다. 이러한 연구방법을 통해 도출된 결과를 통해 얻어진 결론은 다음과 같다. 첫째, 부모의 운동참여 정도에 따라 팀내 지위가 차이가 있다. 둘째, 부모의 운동참여 정도에 따라 팀 포지션이 차이가 있다. 셋째, 부모의 운동참여 정도가 높을수록 축구선수의 입상경력 많다.