• Steel and Composite Structures
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• 제19권1호
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• pp.131-152
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• 2015

Easy detection and evaluation of defect in the tube structure is a continuous problem and remains a significant demand in tube inspection technologies. This study is aimed to automate defect detection using the pattern recognition approach based on the classification of high frequency stress wave signals. The stress wave signals from vibrational impact excitation on several tube conditions were captured to identify the defect in ASTM A179 seamless steel tubes. The variation in stress wave propagation was captured by a high frequency sensor. Stress wave signals from four tubes with artificial defects of different depths and one reference tube were classified using the autoregressive (AR) algorithm. The results were demonstrated using a dendrogram. The preliminary research revealed the natural arrangement of stress wave signals were grouped into two clusters. The stress wave signals from the healthy tube were grouped together in one cluster and the signals from the defective tubes were classified in another cluster. This approach was effective in separating different stress wave signals and allowed quicker and easier defect identification and interpretation in steel tubes.

• 한국의류학회지
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• 제46권4호
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• pp.672-686
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• 2022

The study classifies and analyzes the lower-body-shape types of female adolescents aged 14 to 16 years to provide meaningful information for making ready-to-wear patterns that are suitable for various female adolescent body types. The body-size data of 830 females aged 14 to 16 years were analyzed from 6th Size Korea anthropometric study. A factor analysis of 27 measurement items related to the lower body extracted 3 factors: waist/upper legs, height of the lower body, and hip area. A cluster analysis classified the female adolescent lower-body types into four clusters: the skinny body type with the shortest lower-body length, the most obese body type with the largest girth, the normal body type with the longest hip length, and the slender body type with the longest lower-body length. The discriminant analysis determined that nine measurement items had the most influence on classifying lower-body-shape types, and discriminant functions were derived. These results are meaningful because they provide more precise information about lower-body-shape types.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권7호
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• pp.1735-1755
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• 2012

Wireless sensor networks (WSNs) are becoming increasingly attractive for a variety of applications and have become a hot research area. Routing is a key technology in WSNs and can be coarsely divided into two categories: flat routing and hierarchical routing. In a flat topology, all nodes perform the same task and have the same functionality in the network. In contrast, nodes in a hierarchical topology perform different tasks in WSNs and are typically organized into lots of clusters according to specific requirements or metrics. Owing to a variety of advantages, clustering routing protocols are becoming an active branch of routing technology in WSNs. In this paper, we present an overview on clustering routing algorithms for WSNs with focus on differentiating them according to diverse cluster shapes. We outline the main advantages of clustering and discuss the classification of clustering routing protocols in WSNs. In particular, we systematically analyze the typical clustering routing protocols in WSNs and compare the different approaches based on various metrics. Finally, we conclude the paper with some open questions.

• 대기
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• 제17권1호
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• pp.45-53
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• 2007

In order to investigate the impacts of heat wave on human health, cluster analysis of meteorological elements (e.g., temperature, dewpoint, sea level pressure, visibility, cloud amount, and wind components) for identifying offensive synoptic air masses is employed. Meteorological data at Seoul during the past 30 years are used. The daily death data at Seoul are also employed. Occurrence frequency of heat waves which is defined by daily maximum temperature greater than the threshold temperature (i.e., $31.2^{\circ}C$) was analyzed. The result shows that the frequency and duration of heat waves at Seoul are increasing during the past 30 years. In addition, the increasing trend of the frequency and duration clearly appears in late spring and early autumn as well as summer. Factor analysis shows that 65.1% of the total variance can be explained by 4 components which are linearly independent. Eight clusters (or synoptic air masses) were classified and found to be optimal for representing the summertime air masses at Seoul, Korea. The results exhibit that cluster-mean values of meteorological variables of an offensive air mass (or cluster) are closely correlated with the observed and standardized deaths.

• 한국IT서비스학회지
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• 제15권2호
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• pp.21-33
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• 2016

Recently, T-Commerce is emerging to provide new services, with the proliferation of digital broadcasting services. However, T-Commerce market and TV home shopping market are being classified as a legal policy on other markets, such as regulated in the service of live broadcasts. The factor that has inhibited activation T-Commerce related to the lack of appropriate institutions and legal systems in the market, despite the environment with the digital broadcasting service is being spread. We were performed conjoint analysis. For this analysis, we select attributes as a quality attractive factors that significantly affects the satisfaction of TV based shopping customers through previous studies. The results showed that the TV-based shopping customers are important to think 'Responsive', 'Playfulness', 'Live broadcast', 'Convenience' and 'Bidirectional' in the order. The 'Responsive' and 'Live broadcast' of such attributes are served as possible only in TV home shopping, because these attributes don't service due to legal and institutional regulations in T-commerce market. The cluster analysis result also showed that TV shopping consumers are more important to think 'Responsive', 'Playfulness', 'Live broadcast' than 'Convenience' and 'Bidirectional', except one of the classification clusters. If real-time broadcast service is impossible because of the legal and institutional regulations, it seems to require the expansion of the services linked the terrestrial broadcasting to the activating T-Commerce market.

• 한국항해항만학회지
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• 제27권3호
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• pp.315-320
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• 2003

Since the beginning of open-door policy, China has been making rapid annual growth with an average 10% economic development. And due to this rapid growth, cargo volumes via ports have been also rapidly increased, and accordingly, current China government has intensively invested in port development. Further, this development project is significantly big scale, compared with those project which Korea and Japan have. Thus, China is beginning to threaten Korean ports, especially Busan port which try to be a hub port in Northeast Asia. For this reason, it has been very important issue for Korea and Busan port to investigate or analyze Chinese ports based on empirical data. Especially, although various studies related to Shanghai and Hong Kong have been conducted, the competitiveness of overall Chinese major ports has been little studied. In this paper, we analyzed competitiveness level of eight Chinese ports with capabilities as container terminal, based on reliable sources. From data analysis, eight Chinese ports were classified into four groups according to competitiveness level. Rankings among four clusters based on competitiveness level are cluster(Hone Kong), cluster C(Shanghai), cluster A(Qingdao, Tianjin, and Yantian) and cluster D(Dalian, Shekou, and Xiamen).

• 한국정보처리학회논문지
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• 제7권9호
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• pp.3029-3036
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• 2000

영상분할은 컴퓨터비전 시스템에서 영상정보추출의 중요한 과정 중의 하나이다. 이중에서 퍼지 클러스터링 방법은 영상분할에 광범위하게 사용되고 있다. 대부분의 퍼지 클러스터링 방법으로는 FCM 알고리즘이 사용된다. 그러나 FCM 알고리즘은 클러스터의 중심과 데이터간의 거리에 의존하기 때문에 클러스터 크기가 다를 경우에는 데이터가 오분류될 수 있다. 본 논문에서는 클러스트 크기에 상관없이 데이터를 분류할 수 있는 평균내부거리를 이용한 퍼지 클러스터링 알고리즘을 제안하였다. 평균내부거리는 각 데이터로부터 해당 클러스터 중심까지의 거리를 평균한 값으로 클러스터의 크기와 밀도에 비례한다. 실험 결과를 통하여 제안된 방법이 분류 엔트로피와 적합도 함수에 의해서 좋은 결과를 보여주고 있음을 증명하였다.

• 한국농공학회논문집
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• 제53권6호
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• pp.31-41
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• 2011

This study was conducted to predict future land-cover changes under climate change scenarios and to cluster analysis of regional land-cover characteristics. To simulate the future land-cover according to climate change scenarios - A1B, A2, and B1 of the Special Report on Emissions Scenarios (SRES), Dyna-CLUE (Conversion of Land Use Change and its Effects) was applied for modeling of competition among land-use types in relation with socioeconomic and biophysical driving factors. Gyeonggi-do were selected as study areas. The simulation results from 2010 to 2040 suggested future land-cover changes under the scenario conditions. All scenarios resulted in a gradual decrease in paddy area, while upland area continuously increased. A1B scenario showed the highest increase in built-up area, but all scenarios showed only slight changes in forest area. As a result of cluster analysis with the land-cover component scores, 31 si/gun in Gyeonggi-do were classified into three clusters. This approach is expected to be useful for evaluating and simulating land-use changes in relation to development constraints and scenarios. The results could be used as fundamental basis for providing policy direction by considering regional land-cover characteristics.

• 품질경영학회지
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• 제47권2호
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• pp.381-395
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• 2019

Purpose: This study aims to conduct a systematic literature review to suitably identify wide and specific issues and topics on service quality in supply chain. Methods: This study is to investigate service quality in supply chain research using a systematic literature review methodology. In order to extract influential journals and papers, we used the SJR impact factor provided by the SCOPUS database. The collected 169 papers were analyzed using bibliometric analysis, citation analysis as well as keywords network. Results: We conducted a bibliometric analysis to identify top authors contributing to service quality in supply chain and their issues, and further examined important keywords and new emerging keywords. In addition, we extracted five influential papers by PageRank to clarify critical issues and divided into five clusters to identify topics of service quality in supply chain by using network-based approach. In order to examine comprehensive issues and topics of service quality in supply chain, we constructed a keyword network to observe difference in the classification of important keywords across network centrality measures. Conclusion: Our study reviewed literature on service quality in supply chain and explored the future directions and trends of service quality in supply chain.

• 한국정보처리학회논문지
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• 제7권7호
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• pp.2108-2115
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• 2000

The conventional Boolean retrieval systems based on vector spae model can provide the results of retrieval fast, they can't reflect exactly user's retrieval purpose including semantic information. Consequently, the results of retrieval process are very different from those users expected. This fact forces users to waste much time for finding expected documents among retrieved documents. In his paper, we designed a bayesian SOM(Self-Organizing feature Maps) in combination with bayesian statistical method and Kohonen network as a kind of unsupervised learning, then perform classifying documents depending on the semantic similarity to user query in real time. If it is difficult to observe statistical characteristics as there are less than 30 documents for clustering, the number of documents must be increased to at least 50. Also, to give high rank to the documents which is most similar to user query semantically among generalized classifications for generalized clusters, we find the similarity by means of Kohonen centroid of each document classification and adjust the secondary rank depending on the similarity.