• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.461-470
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• 2005

This paper suggests a new policy for consolidating a company's profits by segregating the clients using the contents service and allocating the media server's resources distinctively by clusters using the cluster analysis method of CRM, which is mainly applied to marketing. In this case, CRM refers to the strategy of consolidating a company's profits by efficiently managing the clients, providing them with a more effective, personalized service, and managing the resources more effectively. For the realization of a new service policy, this paper analyzes the level of contribution $vis-\acute{a}-vis$ the clients' service pattern (total number of visits to the homepage, service type, service usage period, total payment, average service period, service charge per homepage visit) and profits through the cluster analysis of clients' data applying the K-Means Method. Clients were grouped into 4 clusters according to the contribution level in terms of profits. Likewise, the CRFA (Client Request Filtering algorithm) was suggested per cluster to allocate media server resources. CRFA issues approval within the resource limit of the cluster where the client belongs. In addition, to evaluate the efficiency of CRFA within the Client/Server environment the acceptance rate per class was determined, and an evaluation experiment on network traffic was conducted before and after applying CRFA. The results of the experiments showed that the application of CRFA led to the decrease in network expenses and growth of the acceptance rate of clients belonging to the cluster as well as the significant increase in the profits of the company.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.170-180
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• 2010

With development of the earth's subsurface space, the need for a reliable subsurface spatial model such as a cross-section, boring log is increasing. However, the ground mass was essentially uncertain. To generate model was uncertain because of the shortage of data and the absence of geotechnical interpretation standard(non-statistical uncertainty) as well as field environment variables(statistical uncertainty). Therefore, the current interpretation of the data and the generation of the model were accomplished by a highly trained experts. In this study, a geotechnical ontology model was developed using the current expert experience and knowledge, and the information content was calculated in the ontology hierarchy. After the relative distance between the information contents in the ontology model was combined with the distance between cluster centers, a cluster analysis that considered the geotechnical semantics was performed. In a comparative test of the proposed method, k-means method, and expert's interpretation, the proposed method is most similar to expert's interpretation, and can be 3D-GIS visualization through easily handling massive data. We expect that the proposed method is able to generate the more reasonable subsurface spatial information model without geotechnical experts' help.

• The Korean Journal of Applied Statistics
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• v.31 no.4
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• pp.517-528
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• 2018

We provide R scripts to detect outliers in multivariate data and visualization. Detecting outliers is provided using three approaches 1) Robust Mahalanobis distance, 2) High Dimensional data, 3) density-based approach methods. We use the following techniques to visualize detected potential outliers 1) multidimensional scaling (MDS) and minimal spanning tree (MST) with k-means clustering, 2) MDS with fviz cluster, 3) principal component analysis (PCA) with fviz cluster. For real data sets, we use MLB pitching data including Ryu, Hyun-jin in 2013 and 2014. The developed R scripts can be downloaded at "http://www.knou.ac.kr/~sskim/ddpoutlier.html" (R scripts and also R package can be downloaded here).

• Journal of Korean Clinical Nursing Research
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• v.29 no.3
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• pp.337-347
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• 2023

Purpose: The objectives of this study were to categorize the conflict management types of preceptor nurses and determine the effects of these types on preceptors' role perception and core competencies. Methods: Data was collected from 192 preceptor nurses with at least two years experiences in general hospitals, from July 1 to July 31, 2022. Conflict management type, preceptor role perception, and core competency were investigated using structured instruments. The data was analyzed using K-means cluster analysis, Independent samples t-test, One-way ANOVA with Scheffé's test, and multiple regression analysis. Results: The conflict management types were categorized into four types; comprehensive type (cluster 1), integrating, obliging, compromising type (cluster 2), undifferentiated type (cluster 3) and obliging, avoiding type (cluster 4). The effect of conflict management types on preceptors' role recognition occurred in the following order of cluster 2 (integrating/obliging/compromising type), cluster 1 (comprehensive type), and cluster 4 (obliging/avoiding type). Next, cluster 1 (comprehensive type), cluster 2 (integrating/obliging/compromising type), and cluster 4 (obliging/avoiding type) were shown in the order of the impact on the core competencies of the preceptor. Conclusion: When preceptor nurses use a mixture of various attributes of conflict management evenly, they have been shown to demonstrate effective preceptor role recognition and core competencies. Therefore, it is proposed that future development of conflict management training programs for preceptor nurses should begin with identifying their conflict management type, followed by creating a program that addresses any deficiencies.

• Journal of Intelligence and Information Systems
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• v.7 no.2
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• pp.35-49
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• 2001

Over the years, cluster analysis has become a popular tool for marketing and segmentation researchers. There are various methods for cluster analysis. Among them, K-means partitioning cluster analysis is the most popular segmentation method. However, because the cluster analysis is very sensitive to the initial configurations of the data set at hand, it becomes an important issue to select an appropriate starting configuration that is comparable with the clustering of the whole data so as to improve the reliability of the clustering results. Many programs for K-mean cluster analysis employ various methods to choose the initial seeds and compute the centroids of clusters. In this paper, we suggest a methodology to evaluate various clustering programs. Furthermore, to explore the usability of the methodology, we evaluate four clustering programs by using the methodology.

• Journal of the Korean Dietetic Association
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• v.19 no.1
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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.

• Korean Journal of Adult Nursing
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• v.21 no.6
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• pp.705-717
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• 2009

Purpose: The purpose of this study was to identify symptom clusters in patients with breast cancer and to investigate the associations among them with functional status and quality of life (QOL). Methods: A convenient sample of 303 patients was recruited from an oncology-specialized hospital. Results: Two distinct clusters were identified: A gastrointestinal- fatigue cluster and a pain cluster. Each cluster significantly influenced functional status and QOL. Based on these two clusters, we identified subgroups of symptom clusters using K-means cluster analysis. Three relatively distinct patient subgroups were identified in each cluster: mild, moderate, and severe group. Disease-related factors (i.e., stage, metastasis, type of surgery, current chemotherapy, and anti-hormone therapy) were associated with these subgroups of symptom clusters. There were significant differences in functional status and QOL among the three subgroups. The subgroup of patients who reported high levels of symptom clusters reported poorer functional status and QOL. Conclusion: Clinicians can anticipate that breast cancer patients with advanced stage, metastasis, and who receive mastectomy, and chemotherapy will have more intense gastrointestinal-fatigue or pain symptoms. In order to enhance functional status and QOL for patients with breast cancer, collective management for symptoms in a cluster may be beneficial.

• Journal of Environmental Science International
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• v.31 no.12
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• pp.999-1012
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• 2022

To investigate the reason for the spatial difference in PM_2.5 (Particulate Matter, < 2.5 ㎛) concentration despite a similar synoptic pattern, a synoptic analysis was performed. The data used for this study were the daily average PM_2.5 concentration and meteorological data observed from 2016 to 2020 in Busan and Seoul metropolitan areas. Synoptic pressure patterns associated with high PM_2.5 concentration episodes (greater than 35 ㎍/m³) were analyzed using K-means cluster analysis, based on the 900 hPa geopotential height of NCEP (National Centers for Environmental Prediction) FNL (Final analysis) data. The analysis identified three sub-groups related to high concentrations occurring only in Busan and Seoul metropolitan areas. Although the synoptic patterns of high PM_2.5 concentration episodes that occur independently in Busan and Seoul metropolitan areas were similar, there was a difference in the intensity of pressure gradient and its direction, which tends to be an important factor determining the movement time of pollutants. The spatial difference in PM_2.5 concentration in the Korean Peninsula is due to the difference and direction of the atmospheric pressure gradient that develops from southwest to northeast direction.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.447-458
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• 2020

This study presents the K-means clustering analysis-based classification of the meteorological patterns affecting the occurrence of high PM₁₀ concentration in the southeastern region of the Korean peninsula for the last five years (2014-2018). Regional differences in Busan, Ulsan, and Gyeongnam related to high PM₁₀ episodes, were clarified through the statistical comparison study using synoptic scale meteorological elements using NCEP (National Centers for Environmental Prediction/FNL (Final Operational Global Analysis) re-analysis meteorological data. Meteorological patterns were classified into a total of five categories (C1-C5). The incidence of each cluster was 24.8% (C1), 21.3% (C2), 20.4% (C3), 17.3% (C4), and 16.2% (C5), respectively. The high PM₁₀ concentration in the southeastern region resulted from long and short range transports (C1, C3, C5) from outside of the region, and the emissions (C2, C4) inside the region. In the high PM₁₀ episodes in Busan, Ulsan, and Gyeongnam regions, meteorological characteristics such as different geopotential height and wind speed at 500 hPa in each cluster and the change in the location of high pressure over Korean Peninsula is strongly associated with the dispersion of PM₁₀ around inventories in the region and the tendency of long-range transportation of PM₁₀ emitted from outside of region.

• The Journal of Fisheries Business Administration
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• v.40 no.3
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• pp.127-146
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• 2009

This study is to estimate the factor weights of the reasons for decreases in marine fishery resources using the Analytical Hierarchy Process. Furthermore, it classifies 20 fishes under a fishery resource recovery plan into various groups of fishes according to these factor weights using the non-hierarchial cluster analysis. The factors of decreases in marine fishery resources are identified as bio-ecological, technology-system, economic-business, and fishing village-society factors. Two of the most important factors of decreases in resource are turned out to be the economic-business and bio-ecological factors, estimated as 31% and 30% respectively. The technology-system and fishing village-society factors are estimated as 21% and 18% respectively. The study utilizes non-hierarchical cluster analysis in order to classify 20 fishes into 2, 3, and 4 groups. K-means cluster analysis is applied for grouping in conjunction with ANOVA to identify statistical differences in factors. Once again, the economic-business and bio-economic factors play main role in grouping 2-groups of fishes case. The third group of fishes in addition to the previous 2 groups of fishes appears as those 4 factors of decrease evenly play about the same role at a 3-groups of fishes case. Finally, the economic-business and bio-economic factors are turned out to be evenly important in the 4th group once there are 4-groups of fishes.