• IE interfaces
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• v.20 no.4
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• pp.515-524
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• 2007

This paper introduces the methodology for restrict adjustment of 25 mail sorting centers including 3 new mail sorting centers to balance their work loads and minimize their operating costs. We calculated the capacity of mail sorting centers considering mail types and analyzed the collection/delivery mail volume of 214 post offices to measure the work loads of mail sorting centers. We also developed the mathematical model and genetic algorithm to find the optimal solution for this problem.

• Journal of the Korean Mathematical Society
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• v.56 no.1
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• pp.39-52
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• 2019

The aim of this paper is to introduce the notions of (quasi) weakly almost periodic point, measure center and minimal center of attraction of amenable group actions, explore the connections of levels of the orbit's topological structure of (quasi) weakly almost periodic points and study chaotic dynamics of transitive systems with full measure centers. Actually, we showed that weakly almost periodic points and quasiweakly almost periodic points have distinct orbit's topological structure and proved that there exists at least countable Li-Yorke pairs if the system contains a proper (quasi) weakly almost periodic point and that a transitive but not minimal system with a full measure center is strongly ergodically chaotic.

• Journal of the Korean Home Economics Association
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• v.36 no.6
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• pp.95-108
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• 1998

This study is the second study which was aimed to validate the Infant/ Toddler Environment Rating Scale(ITERS). The test-retest reliability included 10 infant/toddler classes among 30 national/public and private child care centers in Inchon city which had been observed in the first validation study. The Spearman's correlation coefficient for test-retest reliability was ranged from .52 to .84. In addition, two raters observed 10 family day care centers in Inchon city, where two observers independently rated each centers on the ITERS during a single visit. The Spearman's correlation coefficient for interrater reliability was ranged from.72 to .99 For the second measure of content validity, experts who were working in day care centers and who were graduate students, lecturers, or professors majoring child studies rated the appropriateness of each ITERS items for the provision of high-quality programs for infants and toddlers, using a 1(low) to 5(high) scale. The mean rating was ranged from 2.52 to 4.52. In sum, when the rating scores were analyzed by the type of child care centers, national/public child care centers have better quality than private or family child care centers.

• Health Policy and Management
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• v.6 no.2
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• pp.91-114
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• 1996

In this research, the Data Envelopment Analysis(DEA) was applied to measure production efficiency of Public Corporation Medical Centers(PCMCs) operating in Korea. The focus of this research is triple. First, identifing convenience and usefulness of DEA to measure the relative efficiency among PCMCs. Second, assessing magnitudes of the relative efficiency for each PCMC. Third, adding insights into some factors resulting inefficiency in PCMCs. Then, in this paper technical efficiency and scale efficiency measured by DEA[introduced by Charnes, Cooper, and Rhoides(1978) and Banker, Charnes, and Cooper(1984)] were analyzed and a new separate variable was introduced which makes it possible to determine whether operations were conducted in regions of increasing, constant or decresing returns to scale(in multiple input and output situations). And a multi-factor Tobit analysis was conducted to see which variables are associated with PCMC's efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3121-3143
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• 2019

Segmentation plays an important role in the field of image processing and computer vision. Intuitionistic fuzzy C-means (IFCM) clustering algorithm emerged as an effective technique for image segmentation in recent years. However, standard fuzzy C-means (FCM) and IFCM algorithms are sensitive to noise and initial cluster centers, and they ignore the spatial relationship of pixels. In view of these shortcomings, an improved algorithm based on IFCM is proposed in this paper. Firstly, we propose a modified non-membership function to generate intuitionistic fuzzy set and a method of determining initial clustering centers based on grayscale features, they highlight the effect of uncertainty in intuitionistic fuzzy set and improve the robustness to noise. Secondly, an improved nonlinear kernel function is proposed to map data into kernel space to measure the distance between data and the cluster centers more accurately. Thirdly, the local spatial-gray information measure is introduced, which considers membership degree, gray features and spatial position information at the same time. Finally, we propose a new measure of intuitionistic fuzzy entropy, it takes into account fuzziness and intuition of intuitionistic fuzzy set. The experimental results show that compared with other IFCM based algorithms, the proposed algorithm has better segmentation and clustering performance.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.518-521
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• 2008

When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. And we estimated the aerodynamical effects by the results of the real train experiments by using KTX.

• Health Policy and Management
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• v.9 no.4
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• pp.87-119
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• 1999

The main purpose of this research is to measure and analyze how productive the health centers are and how much inputs(or outputs) in the inefficient health centers should be decreased(or increased) for efficiency. The evaluation of the performance of health centers gives a strong incentive to improve resource allocation in regional health planning. It has been, however, implemented very rarely until now. In this regard, this paper measures the performance of the health centers with a single indicator for multiple-outputs in terms of productivity(technical efficiency), based on Data Envelopment method. The 20 Kyungnam health centers which provide clinic services and specific primary health care services were analyzed. The results show that 50.0% of 20 health centers were productive with respective to overall technical efficiency, 65.0% were productive for pure technical efficiency, and 50.0% for scale efficiency. The inefficient group includes Geoje, Mahsan, Miryang, Sahchun, Tongyoung, Gosung, Nahmhae, Euryang, Hahmahn, Hahbchun health centers. The worst case was identified as Tongyoung health center which represented a 47.5% efficiency, compared with productive health centers. The empirical results for input-output analysis indicates that the low-productive health centers have excessive manpower in administration department, producing low outputs in clinical services and vaccination program. These findings imply that a systemic evaluation of the performance of the Korean health centers and the subsequent structural reform are strongly required.

• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.130-130
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• 1999

In this paper, we propose a novel design method for improving performance of existing FCM-type clustering algorithms. First, we define the performance measure which focuses on bothcompactness and separation of clusters. Next, we optimize this measure using evolution program.Especially the proposed method has following merits: ① using evolution program, it solves suchproblems as initialization, number of clusters, and convergence to local optimum ② it reduces searchspace and improves convergence speed of algorithm since it represents chromosome with possiblepotential centers which are selected possible candidates of centers by density measure ③ it improvesperformance of clustering algorithm with the performance index which embedded both compactnessand separation Properties ④ it is robust to noise data since it minimizes its effect on center search.

• Korean Journal of Child Studies
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• v.27 no.4
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• pp.185-200
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• 2006

This study intended to provide basic materials for establishing a diversity of plans for assisting childcare centers, by examining differences between self-evaluation and professional evaluation in childcare centers with less than 21 children. Data were collected from 7 childcare centers to measure evaluation in five categories of accreditation. Significant differences were found between self-evaluation and professional evaluation in "child care curriculum" and in "interaction between teachers and children." These results point up the handicap of heavy dependence on self-evaluation as it leads to self-assistance, with limited access to new ideas. On the other hand, "circuit assistance" where a consortium of 2~3 different childcare centers advise and assist each other could effectively stimulate a more professional outlook.

• Korean Journal of Community Nutrition
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• v.6 no.1
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• pp.91-96
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• 2001

The purpose of this study was to identify the determinants of nutrition service utilization in health centers. Utilization of nutrition services for chronic discase were also investigated. Interview survey using questionnaire was conducted to collect the data required for analysis. The study subjects were 300 residents over 40 years of age, and 15 health workers representing health center service personnel in Kypnggi province. A wilcoxon 2-sample test and Kruskal-Wallis test were used to compare the distribution of health centers by health center characteristics and nutrition services. A chi-square test was used to test the association between service utilization and personal variables of the population. A multiple logistic regression analysis was used to measure the relative importance between the variables on service utilization. The results showed that only 10.0% of the study subjects used nutrition services provided by the health centers. Pilot project implementation and location of health centers, as well as educational level of the residents were significant factors influencing the utilization of the nutrition services provided by the health centers. Among the variables, pilot project implementation was the most important factor that influenced the nutrition service utilization in health centers.