• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2389-2413
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• 2015

High data rates in long-term evolution (LTE) networks can affect the mobility of networks and their performance. The speed and motion of user equipment (UE) can compromise seamless connectivity. However, a proper handover (HO) decision can maintain quality of service (QoS) and increase system throughput. While this may lead to an increase in complexity and operational costs, self-optimization can enhance network performance by improving resource utilization and user experience and by reducing operational and capital expenditure. In this study, we propose the self-optimization of HO parameters based on fuzzy logic control (FLC) and multiple preparation (MP), which we name FuzAMP. Fuzzy logic control can be used to control self-optimized HO parameters, such as the HO margin and time-to-trigger (TTT) based on multiple criteria, viz HO ping pong (HOPP), HO failure (HOF) and UE speeds. A MP approach is adopted to overcome the hard HO (HHO) drawbacks, such as the large delay and unreliable procedures caused by the break-before-make process. The results of this study show that the proposed method significantly reduces HOF, HOPP, and packet loss ratio (PLR) at various UE speeds compared to the HHO and the enhanced weighted performance HO parameter optimization (EWPHPO) algorithms.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.16-22
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• 2005

Objective : The authors characterize a syndrome of multiple neurogenic tumors in the spinal canal, which is unclassifiable by the current National Institute of Health[NIH] criteria for neurofibromatosis. Methods : We retrospectively examined cases in which two or more spinal neurogenic tumors were detected by magnetic resonance[MR] imaging and which had been pathologically confirmed. Eighteen patients were recruited between February 1986 and March 2002. According to NIH criteria, eight cases were neurofibromatosis type 1[NF1], four were type 2[NF2], and six were neither type 1 nor type 2 [Unclassifiable : UC]. The locations of lesions, clinical presentations, radiological findings, and pathological results with immunohistochemistry were reviewed. Results : In the case of NF2, three of four cases were intradural tumors. Pathological examinations revealed neurilemmomas in two of four NF2 and all of the UC cases. In the case of NF1, pathological examinations showed seven neurofibromas and one neurilemmoma. Concerning UC, the age at presentation was middle-aged to late [mean age 48.5, range 35 to 64], which contrasted with ordinary NF2, where patients tended to become symptomatic before 20years of age. The pathological examinations of UC cases revealed neurilemmoma similar to most of NF2 and the immunohistochemical study showed characteristic of NF1. Conclusion : Multiple neurogenic tumors in the spinal canal are an under-recognized disease entity. Further studies for genetic aberration in multiple spinal neurogenic tumors are needed.

• Journal of radiological science and technology
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• v.46 no.4
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• pp.303-313
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• 2023

This study aimed to investigate the relevance of cardiovascular disease risk factors AI and AIP, divided into three groups, among 300 individuals who underwent health checkups at the hospital. Various variables such as Age, Sex, BMI, WC, TC, TG, HDL-C, LDL-C, FBS, HbA1C, SBP, DBP, HR, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) were analyzed using statistical methods including frequency analysis, cross-tabulation, one-way ANOVA, Pearson's correlation analysis, and multiple linear regression analysis. The cross-analysis based on cardiovascular disease risk criteria revealed that men and individuals in their 50s had higher cardiovascular disease risk based on AI and AIP. Significant differences were observed in TG, TC, HDL-C, LDL-C, SBP, DBP, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) according to AI criteria. For the AIP criteria, TG, TC, HDL-C, FBS, HbA1C, HR, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) were identified as cardiovascular disease risk factors. FBS and HbA1c showed the highest positive correlation In the correlation analysis, followed by TC and LDL-C. The lowest positive correlation was observed between LDL-C and DBP. In terms of negative correlation, HDL-C and AI had the highest negative correlation, while LDL-C and TG showed the lowest negative correlation. Multiple regression analysis indicated that the AI and AIP risk criteria had explanatory powers of 73.6% and 72.5%, respectively. HDL-C had the greatest negative effect on the AI risk criterion, while TG had the most significant influence on the AIP risk criterion. In conclusion, while other serological variables are important, managing HDL-C and TG levels may help reduce the risk of cardiovascular disease.

• Korean Journal of Health Education and Promotion
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• v.24 no.2
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• pp.15-28
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• 2007

Objectives: In this paper, the survey on internet usage patterns of health consumers was conducted and analyzed in order to determine internet health information assessment criteria for providing correct consumer health information on web-sites. Methods: By using a survey questionnaire with 16 questions on general information and 20 questions on internet health information, data were collected from September 16 to 25, 2005 from 476 participants through an internet web site, http://www.hp.go.kr. Frequency analysis, t-test, and multiple regression were used in order to analyze the difference in assessment criteria, factors influencing assessment criteria, factors influencing user satisfaction, etc. Results: General characteristics of the study population were: the persons over age 40 were the smallest age group; women were accounted for 74.2%; and the persons with average income were the largest income group; and the persons with average health status were the largest health group. Most widely used health information were: exercise, disease, and diet, in order. There was significant difference(p=.001) in importance of assessment criteria between the persons in medical institutions and the persons not in medical institutions. There was no significant difference in other assessment criteria. We also found that contents of websites and easy to use were more important factors than elucidation of information providers and information sources including speciality of information in quality assessment criteria of internet health information. Discussion and Conclusion: Results of this paper were compared with the previous studies from the literatures. Contrary to the previous studies in the literature, there was significant difference in importance of assessment criteria between the persons in medical institutions and the persons not in medical institutions. In order to apply the study results to develop health contents for consumer, there is a need for further upgrade the proposed assessment criteria based on expert opinion.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.57-66
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• 2012

The paper deals with the development of a model for group decision making under multiple criteria. The Multi-criteria group decision making (MCGDM) is the process to determine the best compromise solution in a set of competing alternatives that are evaluated by decision makers having their own preferences on conflicting objectives. For MCGDM, we propose a Mixed-Integer Programming (MIP) model that implements a revised median approach by noticing that the original median approach cannot consider the willingness to reject and the indifferent preference conditions. The proposed MIP model tries to select a common best Pareto-optimal solution by maximizing the overall desirability considering the willingness to reject and the indifferent preference that represent the tolerance measure of each decision maker. To evaluate the effectiveness of the proposed model, we compared the results of the proposed model with those of the median approach. The results showed that the proposed MIP model produces more realistic and better compromised alternative by incorporating the decision maker's willingness to reject and the indifferent preferences over each criteria.

• Journal of Environmental Science International
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• v.29 no.6
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• pp.643-658
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• 2020

Recent economic and income growth in Korea has caused people to seek healthier and happier lives. Forests are seen as spaces that provide tourism and recreation. The Korea forest service and local governments are developing and designating recreational forests but previous studies on the subject have only covered customer satisfaction and how forests are used. As such, the current study aims to find issues with designation criteria for recreational forests used by Gwangju city in Gyeonggi province and suggest improvements to the system. Site E was deemed the most adequate in evaluations of five candidate site. The criteria used in the evaluations were problematic due to (1) a lack of differentiating power in evaluation items, (2) blanket coverage of score ranges, (3) a lack of additional points for special sites, and (4) unclear evaluation indices. Based on the identified issues, the current study suggests introducing additional points and clearly detailing evaluation indices and items to enhance the evaluation of recreational forest candidate sites.

• KIEAE Journal
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• v.10 no.5
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• pp.43-55
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• 2010

This research investigated 162 residential unit plans which were located in Seoul and Gyonggi Province ranging from 58 to $118m^2$ unit net area recently. Through the investigation of unit plans, a matrix was developed based on the 5 criteria for space composition types. 5 criteria are building stock types, W/D ratio of units, unit net area, number of bay to the main orientation, and openness types. After review the matrix, 10 typical unit types were selected. At the same time, quantitative evaluation indicators were developed based on the 4 criteria such as efficiency, openness, flexibility, environmental sustainability. On each criterion, 3 indicators were developed, and measured on 162 residential unit plans. Firstly, correlation analysis were pursued on 5 criteria for space composition types and 12 quantitative evaluation indicators, and reviewed on each other. Finally, quantitative evaluation indicators of 10 typical unit types were displayed on radar charts in order to show the integrated evaluation on 4 criteria such as efficiency, openness, flexibility, environmental sustainability. From the reviews and radar chart analyses, advantages, disadvantages, and improvements on each typical unit type were presented as research results.

• IE interfaces
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• v.1 no.1
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• pp.17-26
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• 1988

This paper describes a nonlinear goal programming approach to the optimal composition of composite solid propellant taking multiple characteristics into consideration synchronously. The nonlinear goal programming model with response functions, restrictions and the optimal value of each characteristic is developed using Scheffe's "Experiments with mixtures" and preference weighting system. Objective functions are described based on process, performance and assurance characteristics. The systematic approach to optimal composition in this study is proved efficient through a CTPB-AL-AP propellant which is one of composite solid propellant systems.

• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.741-748
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• 2012

In this work, we prove the instability of solutions for a class of nonlinear functional differential equations of the eighth order with n-deviating arguments. We employ the functional Lyapunov approach and the Krasovskii criteria to prove the main results. The obtained results extend some existing results in the literature.

• Journal of Korean Society for Quality Management
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• v.19 no.1
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• pp.95-102
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• 1991

This paper is concerned with the production-distribution problem with multiple conflicting objectives. In reality business firms should take account not only of the profit maximization but of various environmental criteria, namely customer services, in order to improve the business logistics. A production-distribution model of goal porgramming type considering the lead time and distribution cost by products is constructed, the solution algorithm is developed, which is based on the Ignizio's method. A numerical example is given to demonstrate the applicability of goal programming for production-distribution problem.