• Journal of Positioning, Navigation, and Timing
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• 제5권2호
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• pp.75-85
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• 2016

The performance of up-to-date mapping functions and various mean temperature equations were analyzed to derive optimal mapping function and mean temperature equation when GNSS precipitable water vapor (PWV) was investigated in the Korean Peninsula. Bernese GNSS Software 5.2, which can perform high precision GNSS data processing, was used for accurate analysis, and zenith total delay (ZTD) required to calculate PWV was estimated via the Precise Point Positioning (PPP) method. GNSS, radiosonde, and meteorological data from 2009 to 2014 were acquired from Sokcho Observatory and used. ZTDs estimated by applying the global mapping function (GMF) and Vienna mapping function 1 (VMF1) were compared with each other in order to evaluate the performance of the mapping functions. To assess the performance of mean temperature equations, GNSS PWV was calculated by using six mean temperature equations and a difference with radiosonde PWV was investigated. Conclusively, accuracy of data processing was improved more when using VMF1 than using GMF. A mean temperature equation proposed by Wu (2003) had the smallest difference with that in the radiosonde in the analysis including all seasons. In summer, a mean temperature equation proposed by Song & Grejner-Brzezinska (2009) had the closest results with that of radiosonde. In winter, a mean temperature equation proposed by Song (2009) showed the closest results with that of radiosonde.

• 정보처리학회논문지D
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• 제11D권6호
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• pp.1287-1294
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• 2004

최근 소프트웨어 신뢰성을 평가하기 위해 신뢰성 측도와 커버리지 간의 관계가 연구되고 있다. 특히 커버리지에 기반한 소프트웨어 신뢰성 성장 모델에서 평균치 함수는 소프트웨어의 신뢰성 성장을 나타내는데 매우 중요한 역할을 한다. 본 논문은 커버리지에 기반한 기존 모형들의 문제점을 평균치 함수와 그 모형이 근거하는 가정을 바탕으로 파악하고, 그 문제점을 해결하기 위한 새로운 평균치 함수를 제안한다. 제안된 새로운 평균치 함수는 불완전 결함 발견과 구문의 반복 실행이 허용되는 일반적인 테스팅 환경에서 도출된 결과이다. 마지막으로 실제 데이터에 제안된 모형을 적용하여 그 성능을 평가한다.

• International Journal of Reliability and Applications
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• 제3권1호
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• pp.1-16
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• 2002

In reliability engineering, the bathtub-shaped hazard rates play an important role in survival analysis and many other applications as well. For the bathtub-shaped, initially the hazard rate decreases from a relatively high value due to manufacturing defects or infant mortality to a relatively stable middle useful life value and then slowly increases with the onset of old age or wear out. In this paper, we present a new two-parameter lifetime distribution function, called the Loglog distribution, with Vtub-shaped hazard rate function. We illustrate the usefulness of the new Vtub-shaped hazard rate function by evaluating the reliability of several helicopter parts based on the data obtained in the maintenance malfunction information reporting system database collected from October 1995 to September 1999. We develop the S-Plus add-in software tool, called Reliability and Safety Assessment (RSA), to calculate reliability measures include mean time to failure, mean residual function, and confidence Intervals of the two helicopter critical parts. We use the mean squared error to compare relative goodness of fit test of the distribution models include normal, lognormal, and Weibull within the two data sets. This research indicates that the result of the new Vtub-shaped hazard rate function is worth the extra function-complexity for a better relative fit. More application in broader validation of this conclusion is needed using other data sets for reliability modeling in a general industrial setting.

• Fibers and Polymers
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• 제6권4호
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• pp.332-335
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• 2005

The fibrogram theory is newly derived from the superposition principle of the conventional staple diagram, in which the left-hand ends of the fibers have to share a common starting point in order for the fiber length distribution to be measured, and the right-hand ends of the fibers form points. It is shown that the fibrogram is the staple diagram of the fiber sample having different random starting points, as well as the double cumulative distribution function of the frequency length function in the length biased sample. Also, the various means, viz. the numerical mean length, numerical mean length in median, length biased mean length, and length biased mean length in median, and the various upper half means, viz. the numerical upper half mean length, numerical upper half mean length in median, length biased upper half mean length, and length biased upper half mean length in median, are discussed in relation to the cotton blending process.

• 재활치료과학
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• 제8권2호
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• pp.43-53
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• 2019

목적 : 본 연구의 목적은 Upper extremity performance test for elderly (TEMPA)의 한국 노인 표준치를 제시하고, 수집된 자료를 바탕으로 한국 노인의 연령별, 성별 손 기능의 특성과 근력의 차이를 알아보는 것이다. 연구방법 : 연구에 참여한 대상자는 60세 이상의 손 기능에 장애가 없는 노인 103명이었다. 손 기능의 특성을 알아보기 위하여 모든 대상자에게 TEMPA 평가를 시행하였고, Jarmar dynamometer, pinch gauge를 사용하여 손과 손가락 근력을 평가하였다. 결과 : 나이가 증가함에 따라 수행 속도와 소 근육의 움직임의 질이 유의미하게 감소하였다. 남성 노인의 수행 속도와 소 근육 움직임의 질이 여성 노인보다 더 높게 유지 되었다. 노인의 손과 손가락의 근력 또한 연령이 증가함에 따라 유의미하게 감소하였다. 결론 : 작업치료사는 노인의 손 기능과 근력 감소에 대한 관심을 가지고 그 기능 수준을 유지하기 위한 중재를 제공하는 것이 필요할 것이다. 본 연구를 통해 TEMPA의 한국 노인 표준치가 확립되었다. 이 자료가 임상적 평가 및 근거 기반의 연구에 있어 유용하게 쓰이기를 기대한다.

• The Journal of Korean Physical Therapy
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• 제19권5호
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• pp.87-96
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• 2007

Purpose: It remains controversial for the effect of daily functioning and quality of life on therapeutic exercise after stroke. The purpose of this study was to describe the effects on daily functioning and QOL. Methods: Outcome measures of daily functioning included, such as the Functional Independence Measure (FIM), Barthel index. Outcome measures of QOL included, such as Stroke Impact Scale(SIS) and the Medical Outcomes Study short-form 36-item questionnaire(SF-36). Results: 125 stroke patients were recruited, who were in or outpatients. The average age was 55.4 years. 64.8% were male. The mean Bathel index and FIM score was 63.7 and 87.5. The mean SIS score were higher in communication and mean SF-36 score were higher in physical pain. In/out patients are associated with SIS (communication, emotion) and SF-36(social function, energy or fatigue). Sex are associated with SF-36 (physical function). Other disease state are associated with SIS(hand function) and SF-36 (physical function). Paralysis portion are associated with SIS(communication, daily activity). Barthel index are associated with SIS(communication, mobility) and SF-36(social function, physical function, role limits due to emotional problems). Conclusion: These findings may provide the useful with rehabilitation professionals, who specilalized in the importance of QOL in designing treatment modalities.

• Archives of Plastic Surgery
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• 제32권6호
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• pp.733-738
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• 2005

Theoretically one might suggest the abdominoplasty can cause respiratory decompensation resulting from musculofascial plication, which reduces the respiratory reserve by decreasing intra-abdominal volume and diaphragmatic excursion. This prospective study was perfomed to evaluate the effect of abdominoplasty and the change of intraoperative Paw on the pulmonary function of 20 consecutive otherwise healthy subjects. The pulmonary function test was performed preoperatively, and repeated 2 months after the operation. Additionally, we monitored intraoperative Paw. Comparison of the pulmonary function test showed a significant decrease(p<0.001) in the mean forced vital capacity(FVC) and the mean forced expiratory volume in one second($FEV_1$) throughout the study period. Postoperatively, the mean FVC decreased by 11.65% and the mean $FEV_1$ decreased by 16.15%. The mean Paw increased by $6.6cmH_2O$($3-12cmH_2O$) by musculofascial plication. And we found that the decrease in FVC and $FEV_1$ was significantly correlated with intraoperative changing of Paw in abdominoplasty(p<0.001). FVC and $FEV_1$ could be decreased by abdominoplasty due to decreasing intra-abdominal volume and diaphragmatic excursion, but there was no respiratory symptom clinically in all patients 2 months after the operation. In conclusion, We found that the decrease in FVC and FEV1 after 2 months of abdominoplasty was significantly correlated with intraoperative Paw change during operation. The intraoperative Paw was increased to $12cmH_2O$ without any respiratory symptom in this study. We suggested that the increase in intraoperative Paw less than about $10cmH_2O$ can not affect on respiratory function clinically.

• 응용통계연구
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• 제11권2호
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• pp.287-302
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• 1998

표본평균(sample mean)의 밀도함수(density function)와 분포함수(distribution function)에 대한 안부점 근사(saddlepoin\ulcorner approximation)는 Daniels(1954, 1987), Lugannani와 Rice(1980)등에 의하여 유도되었으며, 이 근사식들의 정확도는 대표본(large sample)의 경우는 물론 소표본(small sample)의 경우에도 매우 뛰어난 것으로 알려져 있다. 최근 Easton과 Ronchetti(1986)는 일반적 통계량(general statistics)의 밀도함수에 대한 안부점 근사법을 제안하였고, 분포함수에 대한 근사로는 밀도함수에 대한 안부점 근사식을 직접 수치적으로 적분하는 방법을 제안하였다. 본 논문에서는 일반적 통계량의 분포함수에 대한 안부점 근사법을 제안하고, 이를 표본분산(sample variance)과 스튜던트화 평균(studentizd mean)의 분포함수에 대한 근사에 적용하였다.

• Communications for Statistical Applications and Methods
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• 제31권3호
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• pp.291-308
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• 2024

The current article discusses ratio type exponential estimators for estimating the mean of a finite population in sample surveys. The estimators uses robust regression's Huber M-estimation function, and their bias as well as mean squared error expressions are derived. It was campared with Kadilar, Candan, and Cingi (Hacet J Math Stat, 36, 181-188, 2007) estimators. The circumstances under which the suggested estimators perform better than competing estimators are discussed. Five different population datasets with a well recognized outlier have been widely used in numerical and simulation-based research. These thorough studies seek to provide strong proof to back up our claims by carefully assessing and validating the theoretical results reported in our study. The estimators that have been proposed are intended to significantly improve both the efficiency and accuracy of estimating the mean of a finite population. As a result, the results that are obtained from statistical analyses will be more reliable and precise.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1338-1341
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• 2002

The Weibull probability density function and the Rayleigh function are compared by analyzing the relations of the capacity factors which are compared the actual wind speed frequency curve with which are modelled using the probability density functions with different mean wind speeds. For this analysis, the wind speed means of arithmetic, root mean square, cubic mean cuberoot, and standard deviations are computed from the measured wind speed data of a specific site and the coefficients of probability density functions are calculated. The capacity factors for Vestas 850[kW] wind turbine are calculated and analyzed. The results shows that the wind speed frequency curve by Rayleigh function is more close to the actual curve than by Weibull function. The more the wind speed frequency curve is close to the actual one, the more the capacity factors become large values.