• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.23-46
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• 2021

Collaborative filtering, which is often used in personalization recommendations, is recognized as a very useful technique to find similar customers and recommend products to them based on their purchase history. However, the traditional collaborative filtering technique has raised the question of having difficulty calculating the similarity for new customers or products due to the method of calculating similaritiesbased on direct connections and common features among customers. For this reason, a hybrid technique was designed to use content-based filtering techniques together. On the one hand, efforts have been made to solve these problems by applying the structural characteristics of social networks. This applies a method of indirectly calculating similarities through their similar customers placed between them. This means creating a customer's network based on purchasing data and calculating the similarity between the two based on the features of the network that indirectly connects the two customers within this network. Such similarity can be used as a measure to predict whether the target customer accepts recommendations. The centrality metrics of networks can be utilized for the calculation of these similarities. Different centrality metrics have important implications in that they may have different effects on recommended performance. In this study, furthermore, the effect of these centrality metrics on the performance of recommendation may vary depending on recommender algorithms. In addition, recommendation techniques using network analysis can be expected to contribute to increasing recommendation performance even if they apply not only to new customers or products but also to entire customers or products. By considering a customer's purchase of an item as a link generated between the customer and the item on the network, the prediction of user acceptance of recommendation is solved as a prediction of whether a new link will be created between them. As the classification models fit the purpose of solving the binary problem of whether the link is engaged or not, decision tree, k-nearest neighbors (KNN), logistic regression, artificial neural network, and support vector machine (SVM) are selected in the research. The data for performance evaluation used order data collected from an online shopping mall over four years and two months. Among them, the previous three years and eight months constitute social networks composed of and the experiment was conducted by organizing the data collected into the social network. The next four months' records were used to train and evaluate recommender models. Experiments with the centrality metrics applied to each model show that the recommendation acceptance rates of the centrality metrics are different for each algorithm at a meaningful level. In this work, we analyzed only four commonly used centrality metrics: degree centrality, betweenness centrality, closeness centrality, and eigenvector centrality. Eigenvector centrality records the lowest performance in all models except support vector machines. Closeness centrality and betweenness centrality show similar performance across all models. Degree centrality ranking moderate across overall models while betweenness centrality always ranking higher than degree centrality. Finally, closeness centrality is characterized by distinct differences in performance according to the model. It ranks first in logistic regression, artificial neural network, and decision tree withnumerically high performance. However, it only records very low rankings in support vector machine and K-neighborhood with low-performance levels. As the experiment results reveal, in a classification model, network centrality metrics over a subnetwork that connects the two nodes can effectively predict the connectivity between two nodes in a social network. Furthermore, each metric has a different performance depending on the classification model type. This result implies that choosing appropriate metrics for each algorithm can lead to achieving higher recommendation performance. In general, betweenness centrality can guarantee a high level of performance in any model. It would be possible to consider the introduction of proximity centrality to obtain higher performance for certain models.

• Journal of agricultural medicine and community health
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• v.42 no.1
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• pp.24-35
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• 2017

Objectives: This study aimed to evaluate the primary care quality of a public health center in a rural area using the Korean Primary Care Assessment Tool (KPCAT). It also examined some methodological issues in applying the KPCAT and interpreting its results. Methods: Seventy-nine patients who had visited their doctor more than four times responded to the KPCAT questionnaire. Descriptive statistics and a radar chart were used in analyzing data. Sign test was used to test the KPCAT score difference by don't know option scoring methods. Results: Median and interquartile range of the public health center's KPCAT scores were forty-five and sixteen points, respectively. Only the median of the first contact domain reached the expected value of seventy-five points. The proportions of those who scored under the expected value were under fifty percent in two of four comprehensiveness items, all of three coordinating function items, two of five personalized items and all of four family/community orientation items. There were some methodological issues including, how to score don't know option and make sure response scale consistency. Conclusions: There was much room to improve the primary care quality of the rural public health center. Especially, improvement is needed in the domain of coordinating function and family/community orientation. We also hope that methodological improvement of the KPCAT contributes to more valid and reliable primary care assessment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.100-106
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• 2022

Ships are built according to the purpose and operated with individual goals. Operational goals are reflected in the design of the ships and become the main criterion for determining the required ship ability. In general, cargo ships and passenger ships are objectively evaluated in terms of the operation part of the ship and the capacity part of the cargo or passenger, centering on their transportation ability. In consideration of the required ship ability, the built ship can expect effects such as economic feasibility and eco-friendliness in addition to basic characteristics such as stability. Accordingly, the concept of ship ability is expected to be effectively used in the field of training-only ship management by each institution, which plays a pivotal role in training ship-officers. In this study, the basic direction was verified for the ship ability evaluation criteria of training-only ships through the analysis of the internal space of two training-only ships of the Korea Institute of Maritime and Fisheries Technology, which were recently built with a time lag. In the process of building training-only ship or general-purpose training ship, the possibility of using the ship ability standards in securing budget and designing was derived.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.5
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• pp.1-13
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• 2007

In this research, we found out that bridging nodes have great effect on the robustness of protein-protein interaction networks. Until now, many researchers have focused on node's degree as node's essentiality. Hub nodes in the scale-free network are very essential in the network robustness. Some researchers have tried to relate node's essentiality with node's betweenness centrality. These approaches with betweenness centrality are reasonable but there is a positive relation between node's degree and betweenness centrality value. So, there are no differences between two approaches. We first define a bridging node as the node with low connectivity and high betweenness value, we then verify that such a bridging node is a primary factor in the network robustness. For a biological network database from Internet, we demonstrate that the removal of bridging nodes defragment an entire network severally and the importance of the bridging nodes in the network robustness.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.347-358
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• 2016

ICT sector has been made a great deal of achievements for past 20 or more years in the aspects of the industrial promotion and the efficiency improvement under the strong leadership by the government for the informatization and still leads the Korean industries. However, the previous studies are mostly on how the quantitative growth of patents impacts a company's management achievements while being insufficient on the qualitative level. In this study, an analysis is attempted on the impact from the qualitative level of patents held by a ICT company leading Korean industry to its management achievements. In other words, if the concentration of technological innovation activities, a scale to measure the qualitative level of possessed patents is influential to the growth and the profit of a company is analyzed. The analysis result shows that the current time technological superiority index, RTA and the concentration index, CRn of the technological innovation activities significantly impact to the growth and the profit of company. This study demonstrates the positive impact from a highly qualitative level of patents to the growth and the profit of a company in ICT sector in the current circumstance of insufficient researches on the qualitative level of patents. Therefore, this study is expected to present a new start point for the future studies.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.49-66
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• 2015

The increase of social interest for the e-Learning industry leads to the increase of e-learning contents and the system providers which are targeted at private education companies and public institutions. As the e-Learning is used in various areas, the evaluation for evaluation criteria and suitability are needed to provide a high-quality service and reliability. Previous works suggested the evaluation criteria for quality certification, however, the technical evaluation criteria are not provided. In this paper, we suggest the technical evaluation criteria for quality certification of e-Learning contents and describe the detailed features. Through the proposed work, we can establish the technical evaluation criteria and suggest detailed evaluation items for them by providing examples. It is expected that the proposed study is able to be utilized in e-Learning industry, if the policy is reflected and notified according to the feedback of the results of the trial service.

• Science of Emotion and Sensibility
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• v.8 no.4
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• pp.333-344
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• 2005

The sensitivity adjectives on wall paper are collected. With the collected sensitivity adjective, we are going to develop the model which can recommend the wallpaper to customer. A large number of adjectives describing affective responses were collected from such diverse sources as questionnaire survey results, field survey results and internet survey result. To search the representative adjective of collected adjective, we used the diverse statistical analysis method. We attempted to decide the axis name of dimension through the MDS(Multi-Dimensional Scale) analysis method using the similarity matrix an4 to find a three or four reduced factors through the factor analysis method using the varimax rotation method. The result of the analysis showed that the reduced factors could account about $82\%$ when the number of factor is three(popular, elegance, and passable) ant about $93\%$ when the number of factor is four (elegance, passable, beautiful, and affectionate) On the basis of this result, we expect it can be used to develop the model recommending the wallpaper.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.123-133
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• 1985

The authors studied depression in 5,869 college students (male: 3,893, female: 1,976) using Zung's Self-Rating Depression Scale (SDS). The results are as follows: 1) Female college students showed significantly higher total depression scores than male college students (p<0.001). 2) The items of confusion, indecisiveness, and psychomotor retardation were scored higher in both groups and the Items of suicidal rumination, psychomotor agitation, constipation and tachycardia were scored lower in both groups. 3) 18.2% of male college students showed rather serious depression level of score 50 or higher, while 33.1 % of female college students showed the same scores. 4) The psychosocial factors relating to pessimistic views to past, present & future self images showed significantly high depression scores. 5) The depression items of fatigue, irritability, palpitation, hopelessness & dissatisfaction and the anxiety Items of fatigue, anxiousness, tachycardia, apprehension, fear, and body aches & pain were correlated significantly over 0.40 of correlation coefficient.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.225-225
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• 2019

건물, 차량, 사회인프라시설과 달리 농작물이란 물리적인 시설이 아닌 농업경제 활동의 결과물로서 최종적으로 판매를 통해 수익을 창출하는 행위에서 재난으로 인하여 지장을 받게 되는 경제적 피해가 고려되어야 한다. 이를 위해 본 연구는 홍수로 인한 농작물 피해를 "생산비 매몰비용"과 "순수익 손해"를 농작물 피해추정의 척도로 하였다. 생산비 매몰비용이란 경작시작부터 피해발생까지 투입된 생산비의 회수불가에 따른 피해이며, 순수익 손해란 피해발생에 따른 기대 순수익 하락에 따른 피해를 의미한다. 다양한 작물 가운데 10종의 대표작물을 선택하고, 각 작물의 표준생산비와 표준순수익을 농업생산 및 수익과 관련한 통계자료로부터 결정하였다. 이로부터 생육경과율과 홍수 발생시기(6~9월)를 고려하여 월별 투입생산비 및 기대순수익을 결정하였다. 대상지역 내 재난에 노출된 작물정보를 정의하는 농작물 인벤토리는 농림축산식품부에서 제작된 스마트 팜 맵(농경지 전자지도)을 활용하였고, 다양한 작물이 혼재된 밭의 경우 농업면적조사 결과를 토대로 결정한 밭작물 재배현황비를 고려하였다. 홍수에 따른 취약성을 설명하는 농작물 손상함수는 영향인자는 침수심, 침수기간이며, 이를 기준으로 한 손상함수는 농림부의 농업재해피해조사요령과 일본 치수경제조사메뉴얼을 참고하여 제시하였다. 본 연구에서 제시한 농작물 피해 추정 방법은 기존 방법인 다차원 홍수피해산정법(MD-FDA)과 비교할 때 대표작물의 현실화, 국내 실정을 고려한 손상함수, 그리고 면적 기반의 원단위를 사용함으로써 실무적으로 명확하고 실용적으로 사용될 것으로 기대된다.

• Korean Journal of Culture and Social Issue
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• v.19 no.2
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• pp.133-158
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• 2013

The present research aimed at investigating the impacts of volunteer activities on self-development and sociability-development. In study 1, the scale comprised of 15 items was developed to measure the meaningfulness of volunteer activities. An exploratory factor analysis was conducted on the data obtained from 428 undergraduates (193 males and 235 females). A confirmatory factor analysis was then conducted on the data obtained from 280 undergraduates (124 males and 156 females). In study 2, the impacts of volunteer activities on 947 undergraduates (461 males and 486 females) were analyzed in terms of self-development and sociability-development. Self-development consisted of self-evaluation, self-esteem, and quality of life. Sociability-development consisted of pother-acceptances, sense of community, and democratic citizenship. The results showed that not more volunteer activities itself but more meaningfulness of those activities had stronger relations with self-development and sociability-development. Finally, a values of the undergraduates internalized for volunteer activities and their levels of self-development and sociability-development expectation were discussed.