• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6429-6438
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• 2015

Glutathione S-transferases (GSTs) play an important role in detoxification of carcinogenic electrophiles. The null genotypes in GSTM1 and GSTT1 have been implicated in carcinogenesis. Present study was planned to evaluate the influence of genetic polymorphisms of GSTM1 and GSTT1 gene loci in cervical carcinogenesis. The study was conducted in Lok Nayak hospital, New Delhi. DNA from clinical scrapes of 482 women with minor gynaecologic complaints attending Gynaecology OPD and tumor biopsies of 135 cervical cancer cases attending the cancer clinic was extracted. HPV DNA was detected by standard polymerase chain reaction (PCR) using L1 consensus primer pair. Polymorphisms of GSTM1 and GSTT1 were analysed by multiplex PCR procedures. Differences in proportions were tested using Pearson's Chi-square test with Odds ratio (OR) and 95% confidence interval (CI). The risk of cervical cancer was almost three times in women with GSTM1 homozygous null genotype (OR-2.62, 95%CI, 1.77-3.88; p<0.0001). No association of GSTM1 or GSTT1 homozygous null genotypes was observed in women with normal, precancerous and cervical cancerous lesions among ${\leq}35$ or >35 years of age groups. Smokers with null GSTT1 genotype had a higher risk of cervical cancer as compared to non-smokers (OR-3.01, 95% CI, 1.10-8.23; p=0.03). The results further showed that a significant increased risk of cervical cancer was observed in HPV positive smoker women with GSTT1 (OR-4.36, 95% CI, 1.27-15.03; p=0.02) and GSTM1T1 (OR-3.87, 95% CI, 1.05-14.23; p=0.04) homozygous null genotypes as compared to HPV positive non smokers. The results demonstrate that the GST null genotypes were alone not associated with the development of cervical cancer, but interacted with smoking and HPV to exert effects in our Delhi population.

• Communications for Statistical Applications and Methods
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• 제4권2호
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• pp.427-434
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• 1997

The purpose of this paper is to discuss distribution-free tests of hypothesis that the random samples are identically distributed against the epidemic alternative. But most tests that have been considered are depended only on specific null distribution. Two nonparametric tests are considered and compared with a likelihood ratio test by the empirical powers.

• 대한전자공학회논문지
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• 제9권1호
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• pp.1-6
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• 1972

통계적 상관법에 의하여 최대주기계열 신호를 시험신호로 2차 진동계의 임펄스 응답 추정에 관하여 이론적 및 실험적으로 검토 하였고, 그 측정 결과는 비교적 만족스러웠다. 이 방법은 실제 푸로쎄스에 적용시키는 경우 시험신호를 가하는 방법 및 지연신호의 검출 방법의 해결과 더부러 계통의 동정(동정)문제에 크게 기여될 것으로 전망한다.

• Communications for Statistical Applications and Methods
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• 제5권1호
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• pp.35-42
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• 1998

Once a contingency table is constructed, the first interest will be the hypotheses of either homogeneity or independence depending on the sampling scheme. The most widely used test statistic in practice is the classical Pearson's $\chi^2$ statistic. When the null hypothesis is rejected, another natural interest becomes which cell contributed to the rejection of the null hypothesis more than others. For this purpose, so called cell $\chi^2$ components are investigated. In this paper, the influence function of a cell to the $\chi^2$ statistic is derived, which can be used for the same purpose. This function measures the effect of each cell to the $\chi$$^2$ statistic. A numerical example is given to demonstrate the role of the new function.

• International Journal of Aeronautical and Space Sciences
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• 제2권1호
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• pp.44-54
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• 2001

This paper describes the antenna alignment method of the tracking antenna system for LEO satellite. The purpose of the antenna alignment is to reduce the angular error due to the structural alignment and the monopulse null point alignment error. The angular error of 3 axis tracking system is the key performance parameter that should be minimized to accurately track satellite movement. The angular error is analyzed via a simulation and boresight measurement. The simulation is done with formulas to be derived from vector concept for 3-axis movement. The formulas of the structural alignment are verified by comparing the formula result with the field measurement. Also, the angular error due to monopulse null shift is obtained via boresight measurement. Based on the analyzed and measured results, the antenna alignment was performed and was verified via tracking test of operating LEO satellite.

• Communications for Statistical Applications and Methods
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• 제19권2호
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• pp.267-276
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• 2012

Bagai et al. (1989) proposed a distribution-free test for stochastic ordering in the competing risk model, and recently Murakami (2009) utilized a standard saddlepoint approximation to provide tail probabilities for the Bagai statistic under finite sample sizes. In the present paper, we consider the Gaussian-polynomial approximation proposed in Ha and Provost (2007) and compare it to the saddlepoint approximation in terms of approximating the percentiles of the Bagai statistic. We make numerical comparisons of these approximations for moderate sample sizes as was done in Murakami (2009). From the numerical results, it was observed that the Gaussianpolynomial approximation provides comparable or greater accuracy in the tail probabilities than the saddlepoint approximation. Unlike saddlepoint approximation, the Gaussian-polynomial approximation provides a simple explicit representation of the approximated density function. We also discuss the details of computations.

• 유공압시스템학회논문집
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• 제6권2호
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• pp.22-30
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• 2009

An in-process method of diagnosing the spool wear of hydraulic servovalves was explored. The diagnostic method discussed in this paper is for force-control hydraulic servo systems. The key principle used is that pressure sensitivity of a servovalve drops as the valve spool wears out so that it is possible to determine the spool condition by monitoring pressure sensitivity. A diagnostic algorithm was developed and evaluated through numerical simulation and experiments. Two major steps of diagnosis are the evaluation of null bias of the servovalve and the approximation of pressure sensitivity, both of which could be successfully done during normal operation of a servo system. The difference between a new servovalve and a worn valve could be clearly detected in-process, and the diagnostic test was found to be repeatable.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.419-423
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• 2011

AE는 다른 비파괴 검사방법과 달리 가동 상태에서 구조물의 결함이 발생 및 성장을 검출 할 수 있으며, 연속 검사가 가능하다는 장점으로 인하여 대형 구조물의 안정성 평가에 널리 이용되고 있다. 하지만 AE는 20kHz부터 20MHz 사이에 발생하는 음파를 감지하기 위해 센서를 사용하며, 이 센서의 감도에 따라 결과가 달라질 가능성이 존재한다. 이에 본 연구에서는 STS 304와 SS400 강재에 인장실험을 실시하여, 강재의 균열 신호를 탐지하고자 한다. 인장실험에는 스테인리스강 및 탄소강 시편을 준비하였고, 감도가 다른 센서를 이용하여 동일한 인장실험을 실시하였다. 그리고 균열이 발생하는 13개의 신호 파라미터에 대해 군집분석을 실시하여 4가지 종류의 군집으로 분류하였다. 또한 기무가설을 이용한 통계분석을 통해 두 시험편이 다르지 않다는 것을 증명하였다. 이 결과를 바탕으로 본 실험에서 얻은 Waveform이 재료의 균열신호라는 신뢰성을 확인할 수 있었다.

• International Journal of Fluid Machinery and Systems
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• 제10권2호
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• pp.176-188
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• 2017

The nozzle-flapper valves are widely applied as a pilot stage in aerospace and military system. A subject of the analysis presented in this work is to find out a reasonable range of null clearance between the nozzle and flapper. This paper has presented a numerical flow coefficient simulation. In every design point, a parameterized model is created for flow coefficient simulation and cavitation under different conditions with varying gap width and inlet pressure. Moreover, a new test device has been designed to measure the flow coefficient and for visualized cavitation. The numerical simulation and test results both indicate that cavitation intensity gets fierce initially and shrinks finally as the gap width varies from small to large. From the curve, the flow coefficient mostly has experienced three stages: linear throttle section, transition section and saturation section. The appropriate deflection of flapper is recommended to make the gap width drop into the linear throttle section. The flapper-nozzle null clearance is optionally recommended near the range of $D_N/16$. Finally through simulation it is also concluded that the inlet pressure plays a little role in the influence on the flow coefficient.

• 응용통계연구
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• 제26권6호
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• pp.889-902
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• 2013

지금까지 제안되어 있는 다항 로짓 회귀모형의 적합도 검정 방법들에 대하여 저자들이 제안한 방법들이 타당한지를 확인하고자 본 연구를 진행하였다. 여러 검정 통계량들 중 그룹화 전략을 이용한 통계량들 (Fagerland 등, 2008; Bull, 1994; Pigeon과 Heyse, 1999)을 선정하였고, 이러한 통계량의 기반이 되는 피어슨 ${\chi}^2$ 통계량 또한 같이 비교하였다. 제안된 분포가 모의실험의 상황 하에 얻어지는 귀무분포와 유사한지, 그리고 부적절한 모형의 판별을 적절히 수행하는지에 대하여 확인하였으며, 실제 자료에 세 가지 방법을 적용한 결과를 비교, 평가하였다.