• Journal of the Korea Society for Simulation
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• v.18 no.2
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• pp.49-55
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• 2009

In this paper, we investigate an optimal allocation of constant service resources in stochastic system to optimize the expected performance of interest. For this purpose, we use the control variates to estimate the gradients of expected performance with respect to given resource parameters, and apply these estimated gradients in stochastic optimization algorithm to find the optimal allocation of resources. The proposed gradient estimation method is advantageous in that it uses simulation results of a single design point without increasing the number of design points in simulation experiments and does not need to describe the logical relationship among realized performance of interest and perturbations in input parameters. We consider the applications of this research to various models and extension of input parameter space as the future research.

• Survey Research
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• v.8 no.2
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• pp.67-89
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• 2007

The Korea National Health and Nutrition Examination Survey(KNHANES) consists of Health Interview Survey, Health Behaviour Survey, Nutrition Survey, and Health Examination, and is designed to produce a broad range of descriptive health and nutritional statistics for sex and age subdomains of the population. These data can be used to measure and monitor the health and nutritional status of the population of Korea. The survey has been conducted three times from 1998. The Korea Centers for Disease Control and Prevention(KCDC) is preparing for the 4th survey which is to be conducted from 2007 through 2009. This study is to design a sample for the 4th survey. The main new feature of the sampling design is using a rolling sampling design method. Since KCDC has imposed some operational requirements, e,g., the needs of producing the annual national statistics and of year-round data collection by some regular staffs, a rolling sampling design method is introduced. This is the first time in history of applying a rolling sampling design for a national-wide large scale survey in Korea. Bringing in the rolling sampling, measurement variation due to different data collectors may be minimized.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.37-47
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• 2007

The Integrated Public Transport Reforms of the Seoul Metropolitan Government, which were implemented on the $1^{st}$ of July. 2004, launched a new fare allocation method. However, when a Private transit operator or a new transport system is introduced into the existing system, it will cause an allocation problem. Therefore, this study aims to Propose a rational fare allocation method which can be applicable regardless of the number of Public transportation modes or operators. To create alternatives, this study has adopted a fundamental principle of revenue allocation methods for the transit or communications sectors, and has applied it to the current transit system of Seoul. This study kas analyzed results of the cost recovery ratios and characteristics of each alternative through case studies. This study kas Presented an assessment criterion Z in order to select an optimal alternative. The criterion consists of the sum of the cost recovery ratio of each operator and the difference of the cost recovery ratio for each agency in inter-agency transit. Using the assessment criterion. the results showed that Alternative 1 is superior to the others : Alternative 1 is considering passenger-km of each operator and unit cost of passenger-km for each operator.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1204-1208
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• 2005

우리나라의 경우 근래에 들어 도시지역 내배수시설에 대한 문제점들을 개선하기 위하여 정비사업이 활발히 이루어지고 있으나 시설물에 대한 과거 자료의 데이타베이스(database)화가 전무한 실정이며 정비사업을 시행함에 있어서 체계적인 정비사업 시행이 이루어지지 않고 있다. 따라서 본 연구에서는 내배수시설의 수리$\cdot$수문 해석 모듈을 이용하여 우수배제 목적의 합리적 근거를 마련하고, 현재 표본지역의 중요지점에서만 관측되는 불명수에 대하여 근거별로 불명수를 배분하는 불명수 산정모형과 도시 유출 모형을 이용하여 차집관거별로 발생하는 CSOs 발생량을 추정하는 도시 유출 모형 연계 모형을 구축하여 통합한 내배수시설 노후도 평가 모델을 개발하였다. 또한, 시설물 개량사업의 효율성을 높이기 위하여 수리$\cdot$수문 해석 모듈과 노후도 평가모델이 연계된 최적 개$\cdot$보수 scheduling 모델을 구축함으로써 최적개량 의사결정 시스템을 구축하였으며, 구축된 시스템은 실제 사업지역에의 적용성을 검토하여 GUI(Graphical User Interface)를 통한 의사결정 시스템인 내배수시설 유지관리시스템을 구축하였다.

• The Journal of Korean Society for School & Community Health Education
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• v.25 no.1
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• pp.17-28
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• 2024

Background & Objectives: This study aimed to examine the relationship between subjective health perception and health behaviors among adolescents, utilizing raw data from the 8th Korea National Health and Nutrition Examination Survey (2019-2021) while distinguishing between genders. Methods: The study employed data from the 8th Korea National Health and Nutrition Examination Survey (2019-2020), recruiting students from 1st to 3rd grades in middle and high schools nationwide. Through population stratification, sample distribution, and sampling stages, a final sample of 1,065 adolescents aged 12 to 18 years was selected. The collected data were analyzed using SPSS 28.0 (IBM Corp., Armonk, NY, USA) at a significance level of .05. Results: Regarding the general characteristics of the subjects, no statistically significant differences were observed among male students based on school, family structure, and income. However, among female students, a significant difference in subjective health perception was noted, with higher perception among high school students compared to middle school students (p=.001). Significant differences in health behaviors were identified based on family structure for male adolescents, where those living with both parents exhibited more health-promoting behaviors than single-parent adolescents (p=.011). However, no significant difference was observed among female adolescents. In terms of health behaviors related to gender, regular exercise was found to significantly impact subjective health perception in male adolescents (p=.013), while breakfast habits were identified as significant influencers for female adolescents (p<.001). Conclusions: This study revealed gender differences in subjective health perception and health behaviors among adolescents. Based on these findings, there is a perceived need for the development of health promotion programs tailored to the unique needs of male and female adolescents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.422-428
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• 2018

This study was conducted to investigate the effects of trunk stability exercise on knee function, balance and gait in patients who underwent total knee arthroplasty. The subjects of this study were recruited from individuals diagnosed with degenerative arthritis who had undergone total knee arthroplasty. Overall, 24 patients were randomly divided into a control groups and an experimental groups (12 each). The trunk stability exercise was conducted for 4 weeks with three exercises developed in a previous study. The measurement tools used were knee function measurements based on the Lysholm knee score, balance ability measured using a test of TUG and OLS, and a walking ability test measured using a 10MWT. Pre and post test results were within groups were compared using the paired t-test, whole differences between groups were compared using the independent t-test. The experimental group showed significantly enhanced results relative to the control group (p<0.05). Based on these results, trunk stability exercise in parallel with knee joint therapy effectively improves the recovery of patients with total knee arthroplasty.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.69-78
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• 2017

Shannon of the 5G smartphone and Fourier of the signal processing meet in the sampling theorem (2 times the highest frequency 1). In this paper, the initial Shannon Theorem finds the Shannon capacity at the point-to-point, but the 5G shows on the Relay channel that the technology has evolved into Multi Point MIMO. Fourier transforms are signal processing with fixed parameters. We analyzed the performance by proposing a 2N-1 multivariate Fourier-Jacket transform in the multimedia age. In this study, the authors tackle this signal processing complexity issue by proposing a Jacket-based fast method for reducing the precoding/decoding complexity in terms of time computation. Jacket transforms have shown to find applications in signal processing and coding theory. Jacket transforms are defined to be $n{\times}n$ matrices $A=(a_{jk})$ over a field F with the property $AA^{\dot{+}}=nl_n$, where $A^{\dot{+}}$ is the transpose matrix of the element-wise inverse of A, that is, $A^{\dot{+}}=(a^{-1}_{kj})$, which generalise Hadamard transforms and centre weighted Hadamard transforms. In particular, exploiting the Jacket transform properties, the authors propose a new eigenvalue decomposition (EVD) method with application in precoding and decoding of distributive multi-input multi-output channels in relay-based DF cooperative wireless networks in which the transmission is based on using single-symbol decodable space-time block codes. The authors show that the proposed Jacket-based method of EVD has significant reduction in its computational time as compared to the conventional-based EVD method. Performance in terms of computational time reduction is evaluated quantitatively through mathematical analysis and numerical results.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.449-465
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• 2011

The purpose was to contribute substantially in terms of marketing strategic planning and implementation of coffee shops. Additionally, the target was set as the favorite coffee shops on the basis of the young people. Through the IPA Matrix, subdividion variable was derived and by using the variables in each quadrant, tested the variables that have significant effect on satisfaction, reuse, and recommendation intentions. The study results showed that there was a significant difference in the importance performance (IPA) difference analysis of coffee shop service quality elements and this proved that empirically, the expectations were different. Additionally, it was evident that there were statistically significant and not statistically significant elements in the relationship between service quality element and the overall satisfaction rate in each elements shown in the IPA. Through this, it was possible to provide the information on what service quality elements to focus and distribute. It was possible to understand that the ultimate goal should be satisfaction since the overall satisfaction positively affects the reuse and intention of recommendation and it was possible to re-confirm the previous studies which stated that overall satisfaction, reuse, and recommendation intentions have a positive influence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.694-703
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• 2019

This study was to investigate the effect of therapeutic exercise with electrical stimulation on knee joint pain, range of motion and muscle strength in patients who underwent anterior cruciate ligament reconstruction. The subjects of this study were recruited who diagnosed with anterior cruciate ligament rupture and undergoing anterior cruciate ligament reconstruction, total of 20 patients were randomly divided to the 10 control groups and 10 experimental groups. The therapeutic exercise was carried out for 3 weeks with three exercises made by referring to the previous study. The measurement tools used were knee joint pain measurements were made using the visual analogue scale, range of motion was measured using a goniometer, and the muscle strength was measured using a handheld dynamometer. In the statistical analysis, to compare about pre and post test the difference in each same groups was accomplished by using the paired t-test, and compare the difference between the different each groups was accomplished by using the independent t-test. The results of the study showed that the experimental group showed significantly enhanced results than the control group(p<.05). Based on these results, it is concluded that it is effective for the recovery of the patient if the therapeutic exercise with electrical stimulation in parallel with knee joint therapy are performed for the patients with anterior cruciate ligament reconstruction.

• Survey Research
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• v.9 no.3
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• pp.1-21
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• 2008

The housing market in Korea had mainly consisted of Maemae(purchasing market) and Chonsei(rental market). Since 1997 foreign exchange crisis, the rental housing market has experienced substantial changes in preferred rental contracts between Chonsei and monthly-rent. Even though monthly-rent has taken a substantial portion of housing rental contracts, not yet reliable monthly-rent index has been developed. Furthermore, it isn't obvious to define monthly-rent because there are many types of monthly rent structures from full-monthly-rent to monthly-rent-with-variable-deposit. This study is the basic research of developing a housing price index of monthly-rent in accordance with the existing price index of Maemae and Chonsei in Korea. This research has been carried out with the following contents: (1) Constructing the actually desirable concept of monthly-rent through examining monthly-rental market in Korea. (2) Selecting the reasonable method to investigate monthly-rental market, especially monthly-rent-with-variable -deposit. (3) Designing monthly-rental market samples and calculating the price index of monthly-rent based on 2005 Census.