• Clinical and Experimental Pediatrics
• /
• v.51 no.6
• /
• pp.576-583
• /
• 2008

Purpose : The identification of specific behaviors conducive to overeating or inactivity is the cornerstone of obesity management. The Committee on Nutrition of the Korean Pediatric Society developed parent and self-reporting questionnaires about eating behavior and physical activity in 2006. The aim of this study was to evaluate the usefulness of the questionnaires in assessing modifiable lifestyle factors related to obesity. Methods : A retrospective chart review was performed for 177 children (6-11 years old) and 134 adolescents (12-16 years old) from 10 hospitals between May 2006 and January 2007 who had completed parent or self-reporting questionnaires. Cases were divided into normal and overweight groups at or above the age-gender-specific 85th percentile based on 2007 Korean national growth charts. Results : Compared to children, the adolescents tended to have a significantly more sedentary lifestvle and inappropriate dietary behaviors significantly (P<.05). Overweight mothers were significantly associated with overweight children and adolescents (P<.05). Being overweight was significantly associated with a family history of adult diseases for children and adolescents (P<.05). Inappropriate eating behaviors (strong appetite, eating fast, eating until they were full, binge eating, favoring greasy foods) were associated with being overweight in children and adolescents. Sedentary activity such as TV viewing and using a computer were significantly associated with overweight in children and adolescents (P<.05). Conclusion : Intervention to modify obesity-related lifestyle factors is needed before adolescence. These questionnaires are useful in identifying modifiable lifestyle factors and in individual counseling for overweight children and adolescents in pediatric clinics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.11
• /
• pp.479-485
• /
• 2017

This study estimated the non-use values of the Gum river estuary which are not related to the direct or indirect use of the Gum river estuary using the contingent valuation method (CVM). The non-use values of the Gum river estuary were explained and asked to be evaluated in the CVM questionnaire and estimates of the WTPs(willingness-to-pay) were elicited using the Turnbull nonparametric estimation methods on the dichotomous choice CV data. Results found the Turnbull lower bounded mean WTP per year for non-use value of the Gum river estuary was estimated at 5,822 won (95% C.I. 5,295 ~ 6,349 won) from single dichotomous CV data, and 6,205 won (95% C.I. 5,701 ~ 6,710 won) from double dichotomous CV data. The mean of two WTP estimates, 6,014 won (95% C.I. 5,498 ~ 6,529 won), was used to calculate the annual total non-use value of the Gum river estuary. Therefore, the non-use value of the Gum river estuary was estimated at 220.3 billion won (95% C.I. 201.4 - 239.2 billion won) annually. This non-use value of the Gum river estuary was composed of the bequest value totaling 68.3 billion won (95% C.I. 62.5 - 74.2 billion won), the existence value of 58.0 billion won (95% C.I. 53.0 - 63.0 billion won), the option value of 57.7 billion won (95% C.I. 52.7 - 62.6 billion won), and the vicarious consumption value totaling 36.3 billion won (95% C.I. 33.1 - 39.4 billion won).

• The Korean Journal of Applied Statistics
• /
• v.11 no.1
• /
• pp.53-64
• /
• 1998

Recently, it is of great interest among engineers and reliability scientists to consider a statistical model to describe the failure times of various types of repairable systems. The main subject we deal with in this paper is the power law process which is proved to be a useful model to describe the reliability growth of the repairable system. In particular, we derive the bootstrap confidence intervals of the mean time between two successive failures of a repairable system using the time truncated data. We also compare our bootstrap confindence intervals with Crow's (1982) confidence interval.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06d
• /
• pp.221-224
• /
• 2011

본 논문에서는 중첩 된 WBAN(Wireless Body Area Network) 환경에서 비경쟁 전송구간의 신뢰성 있는 전송을 위해 한정된 자원(비경쟁 전송구간)을 각각의 WBAN에게 할당하는 방안을 제안한다. 이를 위해 협동적 게임 이론(cooperative game theory)을 바탕으로 한정된 자원(비경쟁 전송구간)을 효율적이고 공평하게 할당 할 수 있도록 내쉬중재(Nash arbitration) 기법을 통한 자원 할당 방안을 살펴본다. 내쉬중재 협상해법을 통해 WBAN 간 비경쟁 전송구간의 충돌 없이 신뢰성 있는 전송을 보장한다. 또한, 각 WBAN의 비경쟁 전송 구간 내의 디바이스 우선순위와 할당받은 timeslot의 개수를 고려하여 전략 선택에 따른 형평성과 각 WBAN이 비경쟁전송 구간 내에 요구하는 최소한의 timeslot을 보장한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2005.04a
• /
• pp.166-169
• /
• 2005

질적인 속성을 양적인 계열로 전환하여 측정하는 방법으로서 설문의 최소 문항으로서 최대의 효과를 나타내기 위하여 한 항목을 k번 측정하여 평균과 $95\%$ 신뢰구간을 퍼지수로 한 데이터들을 리커트 척도로 활용하여 내분비방법에 의하여 검정을 하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.25 no.4
• /
• pp.191-199
• /
• 2013

It is estimated and analyzed that the design wave height and the confidence interval (hereafter CI) according to the return period using the fourteen-year wave data obtained at Pusan New Port. The functions used in the extreme value analysis are the Gumbel function, the Weibull function, and the Kernel function. The CI of the estimated wave heights was predicted using one of the Monte-Carlo simulation methods, the Bootstrap method. The analysis results of the estimated CI of the design wave height indicate that over 150 years of data is necessary in order to satisfy an approximately ${\pm}$10% CI. Also, estimating the number of practically possible data to be around 25~50, the allowable error was found to be approximately ${\pm}$16~22% for Type I PDF and ${\pm}$18~24% for Type III PDF. Whereas, the Kernel distribution method, a typical non-parametric method, shows that the CI of the method is below 40% in comparison with the CI of the other methods and the estimated design wave height is 1.2~1.6 m lower than that of the other methods.

• Journal of the Economic Geographical Society of Korea
• /
• v.12 no.4
• /
• pp.702-717
• /
• 2009

This study estimates the willingness-to-pay(WTP) for conserving Sindu coastal sand dune and asset value of Sindu coastal sand dune by means of contingent valuation method. CV market scenario is designed to elicitate his/her WTP considering use value and nonuse value of Sindu coastal sand dune. The yearly WTP for Sindu coastal sand dune is 3,059 won(95% C.I. 2,591~3,612 won) in the case of a househodl, therefore amounts to 44 billion won(95% C.I. 37~52 billion won) for the whole nation. We estimate the asset value of Sindu coastal sand dune by 7.5% discount rate to be 587 billion won with 95% confidence interval of 497 to 693 billion won. The direct use value which has accounted for 13.4% is 79 billion won(95% C.I. 67~93 billion won), and the indirect use value which has accounted for 30.2% amounts to 177 billion won(95% C.I. 150~209 billion won), and the option value which has accounted for 19.4% is 114 billion won(95% C.I. 97~135 billion won), and the conservation value which has accounted for 37.0% amounts to 217 billion won(95% C.I. 184~256 billion won).

• The Korean Journal of Applied Statistics
• /
• v.27 no.5
• /
• pp.833-842
• /
• 2014

Non-inferiority trials indicate whether the effect of an experimental treatment is not worse than an active control. Chen et al. (2006) and Kang (2010) proposed a test method for non-inferiority trials using confidence intervals. In this paper, we suggest a new nonparametric method using a confidence interval based on Wilcoxon rank-sum test and Hodges-Lehmann estimator of active control. A Monte-Carlo simulation study compares the type I error and the power of the proposed method with previous methods.

• The Korean Journal of Applied Statistics
• /
• v.28 no.1
• /
• pp.75-82
• /
• 2015

We discuss confidence intervals for sensitive binomial attributes obtained by a direct question method and indirect question method. The Randomized Response Technique(RRT) by Warner (1965) is an indirect question method that uses a randomization device to reduce the response burden of respondents. We used the mean coverage probability (MCP), root mean squared error (RMSE), and mean expected width (MEW) to compare the confidence intervals by the two methods. The numerical comparisons indicated found that the MEW of RRT is too large and the RRT is so conservative that the MCP exceeds a nominal level(${\alpha}$); therefore, it is necessary to complement these problem in order to increase the utility of the indirect question method.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.5
• /
• pp.11-20
• /
• 2014

Due to the importance of vehicle detector which plays an essential role in generating real-life traffic information, maintaining detector data quality is preeminent in advanced traffic management and information systems (ATMIS). To this end, agencies periodically conduct performance tests on detectors. Detector evaluation is generally performed by comparing baseline data with corresponding detector data. Here, two important things need to be addressed; one is errors (or uncertainties) included in baseline data and the other is the confidence interval concept to represent evaluation results of sample data to corresponding ones of population. To resolve these problems, a new detector evaluation scheme is introduced and the scheme is applied to individual level detector evaluations of loop, video image, and radar detectors. The purpose of individual level evaluation is to eliminate the balancing (or cancelling-out) effects of over- and under-counts. As a consequence, the proposed scheme is proven to be effectively applied to real-world detector evaluations.