• International Journal of Highway Engineering
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• v.16 no.5
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• pp.165-171
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• 2014

PURPOSES : The objective of this study is to find Percentile Speed($V_p$) for Appraisal of Road Section with Recurring Congestion. METHODS : Percentile Speed($V_p$) is determined by correlation analysis of CSI that proposed existing literature. and CSI(Consistency Service Index) is a index that subtract service fail frequency from 100 points, and service fail is defined as traffic situation is driving less than 80kph speed. In this study, We analyzed the highest correlation percentile speed associated with CSI. This speed is chosen as a delay decision speed. In order to verifying reliability, it performed a comparison with the previous method. RESULTS : As a result, 30 percentile speed($V_{30}$) was decided as index speed for judgement of recurring congestion section, and through comparison with existing methods, we demonstrated that 30 percentile speed can be useful for judgement of recurring congestion section. CONCLUSIONS : This method to Determine recurring congestion section using the percentile speed($V_{30}$) was proposed for the first time in this paper. This method can be applicated more quickly and easily than existing method for determining of recurring delay section.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.55-63
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• 2001

In this paper, we utilize the asymptotic variance of $C_{pk}$ to propose a two-sided confidence interval based on percentile-t bootstrap method. This confidence interval is compared with the ones based on the standard and percentile bootstrap methods. Simulation results show that percentile-t bootstrap method is preferred to other methods for constructing the confidence interval.l.

• Communications for Statistical Applications and Methods
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• v.28 no.6
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• pp.627-641
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• 2021

An asymmetric least squares estimation method has been employed to estimate linear models for percentile regression. An asymmetric maximum likelihood estimation (AMLE) has been developed for the estimation of Poisson percentile linear models. In this study, we propose generalized nonlinear percentile regression using the AMLE, and the use of the parametric bootstrap method to obtain confidence intervals for the estimates of parameters of interest and smoothing functions of estimates. We consider three conditional distributions of response variables given covariates such as normal, exponential, and Poisson for three mean functions with one linear and two nonlinear models in the simulation studies. The proposed method provides reasonable estimates and confidence interval estimates of parameters, and comparable Monte Carlo asymptotic performance along with the sample size and quantiles. We illustrate applications of the proposed method using real-life data from chemical and radiation epidemiological studies.

• Korean Journal of Community Nutrition
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• v.12 no.6
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• pp.761-772
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• 2007

It has been suggested that vegetables protect the cardiovascular system in part by attenuating blood pressure. The purpose of the present research was to examine blood lipids according to vegetable intakes. Anthropometric measurements, blood pressures, nutrient intakes using the 24-hour recall method, and serum lipids of <50th percentile vegetable intake group (<50th percentile VIG; men=66, women=111) and ${\ge}50th$ percentile vegetable intake group (${\ge}50th$ percentile VIG; men=83, women=94) were estimated. The average age, height, and BMI were 54.7 years, 158.2 cm, 62.2 kg, and $24.9kg/m^2$ for <50th percentile VIG and 53.7 years, 159.6 cm, 63.0 kg, and $24.7kg/m^2$ for ${\ge}50th$ percentile VIG, respectively. The daily food intake of the ${\ge}50th$ percentile VIG was significantly higher than that of the <50th percentile VIG (p<0.001). Also, daily intakes of cereals (p<0.001), legumes (p<0.05), nuts (p<0.05), vegetables (p<0.001), and fruits (p<0.05) of the ${\ge}50th$ percentile VIG were significantly higher than those of the <50th percentile VIG. The daily energy intakes of ${\ge}50th$ percentile VIG and <50th percentile VIG were 1342.7 kcal and 1782.0 kcal (p<0.001), and most nutrient intakes of the ${\ge}50th$ percentile VIG was significantly higher than that of the <50th percentile VIG. Serum cholesterol of the ${\ge}50th$ percentile VIG were significantly lower than that of the <50th percentile VIG (p<0.01). Also, vegetable intake showed significantly negative correlations with total cholesterol (p<0.05) and LDL-cholesterol (p<0.05). Based on these results, it should be emphasized that increase of vegetable intake improves the blood lipid profile.

• Journal of the Korea Society for Simulation
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• v.9 no.4
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• pp.67-75
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• 2000

Often system analysts are interested in the estimation of percentile for system performance. For instance, in PERT network system, the percentile that the project. Typically the control variate method is used to reduce the variability of mean response using the correlation between the response and the control variates with a little additional cost during the course of simulation. In the same spirit, we apply this method to estimate the percentile of project completion time in PERT system, and evaluate the efficiency of the controlled estimator for its percentile.1 Simulation results indicate that the controlled estimators are more effective in reducing the variances of estimators than the simple estimators, however those tend to a little underestimate the percentiles for some critical values. We need more simulation experiments to examine such a kind of bias problem. We expect this research presents a step forward in the area of variance reduction techniques of stochastic simulation.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.2
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• pp.43-51
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• 2011

Probabilistic seismic hazard analysis (PSHA), which can effectively apply inevitable uncertainties in seismic data, considers a number of seismotectonic models and attenuation equations. The calculated hazard by PSHA is generally a value dependent on peak ground acceleration (PGA) and expresses the value as an annual exceedance probability. To represent the uncertainty range of a hazard which has occurred using various seismic data, a hazard curve figure shows both a mean curve and percentile curves (15, 50, and 85). The percentile performs an important role in that it indicates the uncertainty range of the calculated hazard, could be calculated using various methods by the relation of the weight and hazard. This study using the weight accumulation method, the weighted hazard method, the maximum likelihood method, and the moment method, has calculated the percentile of the computed hazard by PSHA on the Shinuljin 1, 2 site. The calculated percentile using the weight accumulation method, the weighted hazard method, and the maximum likelihood method, have similar trends and represent the range of all computed hazards by PSHA. The calculated percentile using the moment method effectively showed the range of hazards at the source which includes a site. This study suggests the moment method as effective percentile calculation method considering the almost same mean hazard for the seismotectonic model and a source which includes a site.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.347-354
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• 1999

Statistical Process Control(SPC) which uses control charts is widely used to inspect and improve manufacturing process as a effective method. A parametric method is the most common in statistical process control. Shewhart chart was made under the assumption that measurements are independent and normal distribution. In practice, this assumption is often excluded, for example, in case of (equation omitted) chart, when the subgroup sample is small or correlation, it happens that measured data have bias or rejection of the normality test. A bootstrap method can be used in such a situation, which is calculated by resampling procedure without pre-distribution assumption. In this study, applying bootstrap percentile method to (equation omitted) chart, it is compared and evaluated standard process control limit with bootstrap percentile control limit. Also, under the normal and non-normal distributions, where parameter is 0.5, using computer simulation, it is compared standard parametric with bootstrap method which is used to decide process control limits in process quality.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.269-275
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• 2018

In order to establish the criterion for analyzing outdoor weather conditions in the greenhouse heating and cooling system design, we analyzed heating and cooling design outdoor temperatures by the annual percentile method and compared with design outdoor temperatures by the existing seasonal percentile method. In the annual percentile method, 0.4%, 1% and 2% of the total 8,760 hours per year are presented as cooling design outdoor temperatures and 99.6% and 99% as heating design outdoor temperatures. When the annual percentile method was adopted, heating design outdoor temperatures increased by 6.7 to 9.6% compared with the seasonal percentile method, and cooling design outdoor temperatures decreased by 0.6 to 1.1%. The maximum heating load in the same greenhouse condition decreased by 3.0 to 3.6% when the annual percentile method was adopted, but the effect on the maximum cooling load was insignificant. Therefore, it is necessary to consider the change of heating design outdoor temperatures to the annual percentile method, but it is not necessary to change the cooling design outdoor temperatures since there is little difference between the two methods.

• The Journal of Pediatrics of Korean Medicine
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• v.18 no.2
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• pp.119-126
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• 2004

Objective : We used herbal medicine to treat various disease and also to keep good general condition of children. We aimed to evaluate the effect of herbal medicine on the growth of children treated with herbal medicine. Method: We studied 187 children who visited the department of Pediatrics, KyungHee Oriental Medical Hospital from March 2004 to August 2004. They meet condition as follows; they were treated for more than 6 months and they visited our clinic more than 3 times. Whenever patients visited our hospital, we measured their height, body weight and obesity degree using DS-102(dszenix, Seoul). We measured height percentile of first time visit, and that of last time visit. And we compared them using the Growth Statistics Curve made by the Korean Association of Pediatrics, 1998. Results : The mean growth of total children showed 4.04 percentile upwardly; the growth- up percentile of boys was 4.52 and that of girls was 3.26. Analysis according to disease resulted as follows; children with respiratory disease showed 10.29 percentile growth-up, digestive disease 4.21percentile, urinary disease 4 percentile, allergic disease 2.65 percentile, weak children 2.52 percentile and other disease 3.19 percentile. Conclusion : Herbal medical treatment helped growth not only in children who took medicine for growth retardation problem but children with various disease. Moreover herbal medical treatment applied to keep good general condition of children also gave positive effect on the growth of children.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.113-121
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• 1997

Human reliability attempts to make precise quantitative analyses and predictions of the performance of human-machine(or product) systems. In order to yield more precise human error analysis, precise human error probabilities(HEPs) must be used in the analysis. However, because human behavior is influenced by factors that are called performance shaping factors(PSFs), the effects of PSFs must be considered to obtain precise HEPs, These are called basic HEPs or situation-specific HEPs. This paper presents a theoretical method for obtaining basic HEPs (i.e. , considering PSFs) in quantitative human error analysis. In this method, the weight which characterizes the degree of importance of several PSFs is obtained by the analytic hierarchy process. The quality scores of PSFs in the task situation are obtained by percentile concept. These scores are used in conjunction with the relative Importance weights of PSFs to compute the composite quality percentile score of PSFs in the task situation. Then, a new mapping method of the composite quality percentile score of PSFs into a situation-specific basic HEP is proposed with a numerical example.