• 대한원격탐사학회지
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• 제19권2호
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• pp.135-147
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• 2003

본 연구는 한반도 위성 영상자료에 다단계 계층군집 영상분류법을 적용하여 관측지역의 피복특성을 분석한다. 다단계 계층군집 영상분류는 크게 두 단계로 이루어진다. 첫 번째 단계는 계층군집에 의해 공간적으로 근접하고 있는 이웃집단간의 결합을 하는 공간확장 영상분할 단계이고 두번째 단계는 결합지역의 공간적 제약 없이 영상분할 단계에서 분할된 집단을 계층군집에 의해 적은 한정적인 수의 클래스로 분류하는 과정이다. 계층군집 영상분류는 수치영상의 계층구조에 근거하여 매 단계 두 개의 집단을 한 개의 집단으로 합병하므로 클래스 수에 따른 분류집단 간의 관계를 나타내는 계층나무를 구성할 수 있다. 실험결과는 계층군집 영상분류에 의해 구성된 계층나무는 토지사용간의 계층구조를 자세히 밝혀주고 토지 피복 특성의 정확한 분석에는 좀 더 자세한 분광정보가 필요함을 보여주고 있다.

• Environmental Engineering Research
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• 제19권3호
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• pp.197-203
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• 2014

This study estimated spatial and seasonal variation of water quality to understand characteristics of Nakdong river basin, Korea. All together 11 parameters (discharge, water temperature, dissolved oxygen, 5-day biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, electrical conductivity, total nitrogen, total phosphorus, and total organic carbon) at 22 different sites for the period of 2003-2011 were analyzed using multivariate statistical techniques (cluster analysis, principal component analysis and factor analysis). Hierarchical cluster analysis grouped whole river basin into three zones, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) based on similarity of water quality characteristics. The results of factor analysis/principal component analysis explained up to 83.0%, 81.7% and 82.7% of total variance in water quality data of LP, MP, and HP zones, respectively. The rotated components of PCA obtained from factor analysis indicate that the parameters responsible for water quality variations were mainly related to discharge and total pollution loads (non-point pollution source) in LP, MP and HP areas; organic and nutrient pollution in LP and HP zones; and temperature, DO and TN in LP zone. This study demonstrates the usefulness of multivariate statistical techniques for analysis and interpretation of multi-parameter, multi-location and multi-year data sets.

• Journal of Animal Science and Technology
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• 제54권6호
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• pp.463-469
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• 2012

This study utilized a standardization and cluster analysis technique for the selection and classification of beneficial bacteria. A set of synthetic data consisting of 100 individual variables with three characteristics was created for analysis. The three characteristics assigned to each independent variable were designated to have different numeric scales, averages, and standard deviations. The variables were bacterial isolates at random, and the three characteristics were fermentation products, including cell yield, antioxidant activity of culture, and enzyme production. A standardization method utilizing a standard normal distribution equation to record fermentation yields of each isolate was employed to weight their different numeric scales and deviations. Following transformation, the data set was analyzed by cluster analysis. The Manhattan method for dissimilarity matrix construction along with complete linkage technique, an agglomerative method for hierarchical cluster analysis, was employed using statistical computing program R. A total of 100 isolates were classified into groups A, B, and C. In a comparison of the characteristics of each group, all characteristics in groups A and C were higher than those of group B. Isolates displaying higher cell yield were classified as group A, whereas those isolates showing high antioxidant activity and enzyme production were assigned to group C. The results of the cluster analysis can be useful for the classification of numerous isolates and the preparation of an isolation pool using numerical or statistical tools. The present study suggests that a simple technique can be applied to screen and select beneficial microbes using the freely downloadable statistical computing program R.

• 대한영양사협회학술지
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• 제19권1호
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• pp.82-94
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• 2013

The purposes of this study were to measure the service mind and customer orientation of employees and to identify the effect of service mind on customer orientation in elementary school foodservices. The questionnaires were distributed to foodservice employees of the 19 elementary schools, but collected from 12 schools in Gwangju, Gyeonggi. The statistical data analysis was completed using SPSS (ver. 18.0) for the independent sample t-test, ANOVA, Cronbach's alpha, principal component analysis, hierarchical & K-means cluster analysis, Pearson' correlation analysis, and multiple regression analysis. Foodservice employees highly rated their service mind (3.94 out of 5 points), especially their perceptions on the importance of service (4.13 points). The effort to provide service was significantly different depending on the serving place (P<0.05). Employees had a high level of customer orientation (4.02 points), which was significantly influenced by age, position, or career (P<0.05), and cook license (P<0.01). As a result of cluster analysis for service mind, employees were divided into two groups: a low-service mind group (cluster 1) and a high-service mind group (cluster 2). Cluster 2 had a significantly higher overall customer orientation than cluster 1 (P<0.001). The pride in providing services (${\beta}$=0.390, P<0.01) and the perception of the importance of services (${\beta}$=0.297, P<0.05) showed a significant and positive effect on customer orientation.

• 한국광물학회지
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• 제12권2호
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• pp.77-90
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• 1999

Characteristics and variations of chemical compositions in Co-rich crusts occurred in the EEZ of the Republic of Marshall Islands were reviewed. Correlation coefficient analysis, hierarchical cluster analysis, and Q-mode factor analysis for 62 samples were done in this study. All data were selected and gathered from the open file report of the cooperative cruise done by United States Geological Survey with Scripps Institute of Oceanography, University of Hawaii or Korea Ocean Research Development Institute. The average of crust thickness. Co content, and Ni content of 62 samples from the 21 seamounts were 30mm, 0.58 wt% and 0.40%, respectively. The mineral phases and associated elements assigned by correlation coefficients, cluster analysis and Q-mode factor analysis are following four. 1) CFA: P, Ca, CO2, Y, Sr: 2) Mn-oxide mineral: As, Mn, Co, Na: 3) Al-silicate mineral: Pd,Si, Al, Cu, Fe: 4) PGE-bearing mineral: Rh, Pt, Ir.

• 전기학회논문지
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• 제64권1호
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• pp.41-47
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• 2015

In recent years, energy supply cases to take advantage of EMS(Energy Management System) are increasing according to high interest of energy efficiency. The important factor for essential and economical EMS operation is the supply and demand plan the hourly power demand of building load using the hierarchical clustering method of variety statistical techniques, and use the real historical data of target load. Also the estimated results of study are obtained the reliability through separate tests of validity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3468-3495
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• 2015

In this paper, we present a multi-chain based hierarchical topology control algorithm (MCHTC) for wireless sensor networks. In this algorithm, the topology control process using static clustering is divided into sensing layer that is composed by sensor nodes and multi-hop data forwarding layer that is composed by leader nodes. The communication cost and residual energy of nodes are considered to organize nodes into a chain in each cluster, and leader nodes form a tree topology. Leader nodes are elected based on the residual energy and distance between themselves and the base station. Analysis and simulation results show that MCHTC outperforms LEACH, PEGASIS and IEEPB in terms of network lifetime, energy consumption and network energy balance.

• 디지털융복합연구
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• 제19권12호
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• pp.557-565
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• 2021

본 연구는 청소년을 대상으로, 부모의 양육태도 유형에 따른 자아존중감과 그릿 정도의 차이를 파악하고자 시도되었다. 한국청소년정책연구원의 한국아동·청소년패널조사(Korea Children Youth Panel Survey: KCYPS) 자료 중 2018년도 조사에 참여한 중학교 1학년 2,438명의 자료를 분석하였다. 수집된 자료는 계층적 군집분석(Hierachical Cluster Analysis)과 비계층적 방법(k-mean cluster analysis)으로 분석하였다. 그 결과, 청소년이 지각한 부모의 양육태도 유형은 '소극적 애정 수용형', '적극적 애정 수용형', '독재적 비일관형', '애정부족 거부형' 4개 유형으로 분류되었다. 또한, 양육태도의 4개 군집별로 자아존중감과 그릿의 정도에 유의한 차이가 있었다. 자아존중감과 그릿 모두 '적극적 애정 수용형'인 군집 2에서 가장 높게 나타났다. 향후, 청소년의 자아존중감과 그릿을 향상시키기 위해 각 군집별로 차별화된 부모교육이 필요하며, 교육 프로그램 개발에 본 연구가 기초자료로 활용될 수 있을 것이다.

• Communications for Statistical Applications and Methods
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• 제22권3호
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• pp.265-276
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• 2015

In this paper, we propose hierarchical cluster analysis and multidimensional scaling for joint distribution valued data. Information technology is increasing the necessity of statistical methods for large and complex data. Symbolic Data Analysis (SDA) is an attractive framework for the data. In SDA, target objects are typically represented by aggregated data. Most methods on SDA deal with objects represented as intervals and histograms. However, those methods cannot consider information among variables including correlation. In addition, objects represented as a joint distribution can contain information among variables. Therefore, we focus on methods for joint distribution valued data. We expanded the two well-known exploratory methods using the dissimilarities adopted Hall Type relative projection index among joint distribution valued data. We show a simulation study and an actual example of proposed methods.

• 한국인터넷방송통신학회논문지
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• 제15권4호
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• pp.63-70
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• 2015

유비쿼터스 시대의 도래와 함께 센서를 기반으로 하는 무선 센서 네트워크의 응용 분야는 광범위하게 확산되고 있다. 따라서 무선 센서 네트워크에서 센서들로부터 수집되는 기밀 데이터를 허가 받지 않은 사용자로부터 보호하기 위해, 널리 사용되어지는 스마트카드와 패스워드 기반의 사용자 인증도 견고한 보안을 요구한다. 최근 무선 센서 네트워크는 클러스터 헤드와 센서 노드 이원화를 통해 운용상 보다 효과적인 계층적 무선 센서 네트워크로 전개 발전되고 있다. 2012년 Das 등은 계층적 무선 센서 네트워크에 실제 적용 가능한 동적 패스워드 기반 사용자 인증 스킴을 제안하였다. 본 논문은 안정성 분석을 통해 Das 등의 스킴이 그들의 주장과 달리 여전히 중간자 공격, 패스워드 추측 공격, 패스워드 변경 공격을 막을 수 없을 뿐 아니라, 필수적인 보안 요구사항인 사용자와 클러스터 헤드 간의 상호인증을 투명하게 제공하지 못함을 입증한다.