• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권5호
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• pp.457-461
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• 2008

무선 애드 혹(ad hoc) 망에서 제안된 응용계층 기반 멀티캐스트 선행 연구는 크게 계층적 구조와 비계층적 라우팅 구조를 갖는 멀티캐스팅 기법으로 분류된다. 이들 제안된 기법들은 애드 흑 노드들의 이동성 변화를 실시간으로 멀티캐스트 라우팅 경로 갱신을 위해 반영하지 못한다. 그러므로, 에너지, 전송률, 시간지연 등 여러 가지 성능 저하의 원인이 된다. 이러한 문제점을 개선하기 위해, 이미 앞선 연구를 통해 암시적 클러스터 기반 멀티캐스트 기법을 제안하였다. 본 논문은 그의 특성을 분석하고 선행 연구된 응용 계층 기반 프로토콜들과 실험을 통한 성능을 검증하고자 한다.

• 한국발생생물학회지:발생과생식
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• 제23권2호
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• pp.193-198
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• 2019

Genomic DNA samples were obtained from cultured penaeid shrimp (Penaeus chinensis) individuals such as fresh shrimp population (FSP) and deceased shrimp population (DSP) from Shinan regions in the Korean peninsula. In this study, 233 loci were identified in the FSP shrimp population and 162 in the DSP shrimp population: 33 specific loci (14.2%) in the FSP shrimp population and 42 (25.9%) in the DSP population. A total of 66 (an average of 9.4 per primer) were observed in DSP shrimp population, whereas 55 unique loci to each population (an average of 7.9 per primer) in the FSP shrimp population. The Hierarchical dendrogram extended by the seven oligonucleotides primers indicates three genetic clusters: cluster 1 (FRESH 01, 02, and DECEASED 12, 13, 15, 16, 17, 19, 20, 22) and cluster 2 (FRESH 03, 04, 05, 06, 07, 08, 09, 10, 11, and DECEASED 14, 18, 21). Among the twenty-two shrimp, the shortest genetic distance that exposed significant molecular differences was between individuals 20 and 16 from the DSP shrimp population (genetic distance=0.071), while the longest genetic distance among the twenty-two individuals that established significant molecular differences was between individuals FRESH no. 02 and FRESH no. 04 (genetic distance=0.477). In due course, PCR analysis has revealed the significant genetic distance among two penaeid shrimp populations.

• 한국식생활문화학회지
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• 제31권1호
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• pp.105-110
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• 2016

The objective of this study was to determine sensory profiles of rice confections. The samples used in this study obtained from Korea (traditional Korea rice snack and local specialty rice snack) and three countries (USA, Japan, and China) were evaluated and compared. The sensory characteristics of five kinds of rice confections were evaluated using a sensory test and were analyzed via quantitative description analysis (QDA), principal component analysis (PCA), and hierarchical cluster analysis (HCA). In the descriptive analysis, 10 trained panelists evaluated sensory characteristics consisting of 19 attributes, and there were significant differences (p<0.05) among the 16 characteristics. For the descriptive data, multivariate analysis of variance was carried out and identified differences among the samples. The PCA of rice confections for the first two principal components could explain 85.66% of the variations. The Korean, Japanese, and Chinese rice confections were savory, gritty, and particle-sized, the other Korean local specialty rice confections were fruity, sweet, honey-flavored, compact, and crispy, and those from the USA were glossy, grainy, bright, adhesive, cohesive, crispy, and sweet.

• Environmental Engineering Research
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• 제24권2호
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• pp.279-288
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• 2019

To obtain insightful knowledge of geochemical process controlling fluoride enrichment in groundwater of the villages near Shilabati river bank, West Bengal, India, multivariate statistical techniques were applied to a subgroup of the dataset generated from major ion analysis of groundwater samples. Water quality analysis of major ion chemistry revealed elevated levels of fluoride concentration in groundwater. Factor analysis (FA) of fifteen hydrochemical parameters demonstrated that fluoride occurrence was due to the weathering and dissolution of fluoride-bearing minerals in the aquifer. A strong positive loading (> 0.75) of fluoride with pH and bicarbonate for FA indicates an alkaline dominated environment responsible for leaching of fluoride from the source material. Mineralogical analysis of soli sediment exhibits the presence of fluoride-bearing minerals in underground geology. Hierarchical cluster analysis (HCA) was carried out to isolate the sampling sites according to groundwater quality. With HCA the sampling sites were isolated into three clusters. The occurrence of abundant fluoride in the higher elevated area of the observed three different clusters revealed that there was more contact opportunity of recharging water with the minerals present in the aquifer during infiltration through the vadose zone.

• 한국통신학회논문지
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• 제38B권6호
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• pp.446-453
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• 2013

무선 센서네트워크에서 클러스터링 기법은 네트워크 확장성과 네트워크 수명 연장에 효율적이라고 인정받고 있다. 본 논문에서는 클러스터 기반 센서 네트워크에서 multi-hop to one-hop 전송 환경을 고려하여 에너지 효율성에 최적인 클러스터 비율(cluster ratio, CR)을 분석하는데 초점을 둔다. 본 논문에서는 지정한 클러스터 비율을 통한 시스템 홉 수(hop-count) 최소화와 노드 간 패킷수신율(packet reception ratio, PRR) 최대화 사이의 이해득실(trade-off) 관계를 분석하고 이 두 요소를 종합적으로 고려하여 목표함수를 유도한다. 제안한 목표함수를 통하여 얻은 최적의 클러스터 비율은 네트워크에서 패킷 전송에 드는 비용뿐만 아니라 노드 간 재전송 오버헤드를 줄여줌으로써 에너지 효율성을 향상시킨다. 본 논문에서 제안한 기법은 최소 홉 수 클러스터링 방안과 비교되며 시뮬레이션을 통하여 향상된 에너지 효율성을 검증하였다.

• Journal of the Korean Data and Information Science Society
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• 제21권6호
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• pp.1353-1359
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• 2010

Basic objective in cluster analysis is to discover natural groupings of items. In general, clustering is conducted based on some similarity (or dissimilarity) matrix or the original input data. Various measures of similarities between objects are developed. In this paper, we consider a clustering of huge categorical real data set which shows the aspects of time-location-activity of Korean people. Some useful similarity measure for the data set, are developed and adopted for the categorical variables. Hierarchical and nonhierarchical clustering method are applied for the considered data set which is huge and consists of many categorical variables.

• 한국발생생물학회지:발생과생식
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• 제18권1호
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• pp.43-49
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• 2014

Three species of Nortamea concinua (NC) and Haliotis discus hannai (HDH) from Tongyeong and Sulculus diversicolor supertexta (SDS) are widely distributed on the coast of the Yellow Sea, southern sea and Jeju Island in the Korean Peninsula under the innate ecosystem. There is a need to understand the genetic traits and composition of three mollusk species in order to evaluate exactly the patent genetic effect. PCR analysis was performed on DNA samples extracted from a total of 21 individuals using seven decamer oligonucleotides primers. Seven primers were shown to generate the unique shared loci to each species and shared loci by the three species which could be clearly scored. A hierarchical clustering tree was constructed using similarity matrices to generate a dendrogram, which was facilitated by the Systat version 10. 236 specific loci, with an average of 56.3 per primer, were identified in the NC species. 142 specific loci, with an average of 44.7 per primer, were identified in the HDH species. Especially, 126 numbers of shared loci by the three species, with an average of 18 per primer, were observed among the three species. Especially, the decamer primer BION-75 generated 7 unique loci to each species, which were identifying each species, in 700 bp NC species. Interestingly, the primer BION-50detected 42 shared loci by the three species, major and/or minor fragments of sizes 100 bp and 150 bp, respectively, which were identical in all samples. As regards average bandsharing value (BS) results, individuals from HDH species (0.772) exhibited higher bandsharing values than did individuals from NC species (0.655). In this study, the dendrogram obtained by the seven decamer primers indicates three genetic clusters: cluster 1 (CONCINNA 01~CONCINNA 07), cluster 2 (HANNAI 08~HANNAI 14), cluster 3 (SUPERTEXTA 15~SUPERTEXTA 21). Comparatively, individuals of HDH species were fairly closely related to that of SDS species, as shown in the hierarchical dendrogram of genetic distances.

• 한국신뢰성학회지:신뢰성응용연구
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• 제5권4호
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• pp.465-486
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• 2005

A unreliable network system results in unsatisfied performance. A performance criterion of a network is throughput and availability. One of the most compelling technological advances of this decade has been the advent of deploying wireless networks of heterogeneous smart sensor nodes for complex information gathering tasks, The advancement and popularization of wireless communication technologies make more efficiency to network devices with wireless technology than with wired technology. Recently, the research of wireless sensor network has been drawing much attentions. In this paper, We evaluate throughput and availability of wireless sensor network, which have hierarchical structure based on clustering and estimate the maximum hroughput, average throughput and availability of the network considering several link failure patterns likely to happen at a cluster consisted of sensor nodes. Also increasing a number of sensor nodes in a cluster, We analysis the average throughput and availability of the network.

• Journal of the Korean Data and Information Science Society
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• 제24권4호
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• pp.783-791
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• 2013

본 논문에서는 대구 경북지역의 24개 4년제 대학교의 대학공시센터에 공시한 대학지표 자료를 사용하였다. 이들 대학지표들 중 재학생 충원률과 건강보험 취업률에 대한 지표를 이용하여 유사 특징을 가지고 있는 대학들을 그룹화 (분류)하여 그룹의 특징을 분석하는데 목적이 있다. SPSS의 계층적 군집분석과 서포트벡터 군집분석을 분석방법으로 활용하여 실험한 결과에서 공통으로 도출할 수 있는 정보를 구하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1237-1255
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• 2014

In wireless sensor networks (WSNs), hierarchical clustering is an efficient approach for lower energy consumption and extended network lifetime. In cluster-based multi-hop communications, a cluster head (CH) closer to the sink is loaded heavier than those CHs farther away from the sink. In order to balance the energy consumption among CHs, we development a novel cluster-based routing protocol for corona-structured wireless sensor networks. Based on the relaying traffic of each CH conveys, adequate radius for each corona can be determined through nearly balanced energy depletion analysis, which leads to balanced energy consumption among CHs. Simulation results demonstrate that our clustering approach effectively improves the network lifetime, residual energy and reduces the number of CH rotations in comparison with the MLCRA protocols.