• 한국정밀공학회지
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• 제21권10호
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• pp.102-108
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• 2004

In this paper, we studied a vibration problem that is critical and common to most precision measurement systems. For micro mechanical part measurements, results obtained from the vision-based precision measurement system may contain errors due to the vibration. In order to defeat this generic problem, for the current study, a PC based image processing technique was used first, to assess the effect of the vibration to the precision measurement and second, to develop an in-situ calibration algorithm that automatically compensate the measurement results in real time. We used a set of stereoscopic CCD cameras to acquire the images for the dimensional measurement and the reference measurement. The mapping function was obtained through the in-situ calibration to compensate the measurement results and the statistical analysis for the actual results is provided in the paper. Based on the current statistical study, it is expected to obtain high precision results for the micro measurement systems.

• Communications for Statistical Applications and Methods
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• 제25권4호
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• pp.355-371
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• 2018

The two parameter negative exponential distribution has many practical applications in queuing theory such as the service times of agents in system, the time it takes before your next telephone call, the time until a radioactive practical decays, the distance between mutations on a DNA strand, and the extreme values of annual snowfall or rainfall; consequently, has many applications in reliability systems. This paper considers an estimation problem of stress-strength model with two parameter negative parameter exponential distribution. We introduce a maximum penalized likelihood method, Bayes estimator using Lindley approximation to estimate stress-strength model and compare the proposed estimators with regular maximum likelihood estimator for complete data. We also introduce a maximum penalized likelihood method, Bayes estimator using a Markov chain Mote Carlo technique for incomplete data. A Monte Carlo simulation study is performed to compare stress-strength model estimates. Real data is used as a practical application of the proposed model.

• 대한전기학회논문지
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• 제40권9호
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• pp.929-936
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• 1991

An estimator for a discrete nonlinear system is derived in the sense of minimum mean square error. An optimal estimator for nonlinear system is very difficult to find and it will be infinite dimensional even if it is found. It has been known that the statistical linearization technique makes it possible to obtain a finite dimensional estimator. In this paper, the procedure of its derivation using the statistical linearization technique that gives an exact mean and variance information is introduced in the sense of minimum mean square error. The derived estimator cannot be clainmed to be globally optimal estimator because it uses the Gaussian assumption to the non-Gaussian distributed nonlinear output. However, the proposed filter exhibits a better performance compared to extended Kalman filter. Simulation results of a simple example present the improvement of the proposed filter in convergent property over the extended Kalman filter.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
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• pp.123-129
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• 2000

SPC is the quality improvement technique of gathering since Motorola of U.S.A. have used SPC technique as a statistical process control method for promoting 6-sigma quality improvement strategy in 1988. In Korea, small and medium-sized enterprises are needed building of a system for statistical production control . In the present study, the methods of building SPC system with a moderate cost using a graphic programs of easy-to-use and high flexibility for small and medium-sized enterprises were inquired. The SPC system which enables statistic marking (maximum, minimum, mean, standard deviation, process capability index) and graph marking (X-Y coordinates and histogram) using LabVIEW 5.0, the graphic program by National Instrument Co., Ltd. was implemented in this study.

• Nuclear Medicine and Molecular Imaging
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• 제41권2호
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• pp.71-77
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• 2007

Advance of neuroimaging technique has greatly influenced recent brain research field. Among various neuroimaging modalities, positron emission tomography has played a key role in molecular neuroimaging though functional MRI has taken over its role in the cognitive neuroscience. As the analysis technique for PET data is more sophisticated, the complexity of the method is more increasing. Despite the wide usage of the neuroimaging techniques, the assumption and limitation of procedures have not often been dealt with for the clinician and researchers, which might be critical for reliability and interpretation of the results. In the current paper, steps of voxel-based statistical analysis of PET including preprocessing, intensity normalization, spatial normalization, and partial volume correction will be revisited in terms of the principles and limitations. Additionally, new image analysis techniques such as surface-based PET analysis, correlational analysis and multimodal imaging by combining PET and DTI, PET and TMS or EEG will also be discussed.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.761-770
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• 1999

A combination procedure of successive occasions sampling and randomized response method is investigated. Randomized response technique is very simple for use in a telephone survey of a sensitive subject. In the suggested randomized response method. the interviewee replies "yes" or "no" to a randomly selected question and the investigator can estimate the proportion of "yes" or "no" answer. When this procedure is used on successive occasions, not only the proportion supporting a candidate and the time change in this supporting proportion can be derived but also the voters' swing in the trend of voters' support can be estimated. A numerical example is given to show how the suggested sampling strategy can be applied to a practical telephone survey.

• 산업경영시스템학회지
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• 제36권1호
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• pp.44-52
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• 2013

For evaluating participation in collaboration project, the peer assement method is mostly used and various scoring methods have been proposed. But, the reliability and validity of the peer assessment method are still doubted for all most method. In order to overcome these weaknesss, some guidelines and training methods have been recommended. In this article, however, statistical technique is proposed for measuring individual contributions to collaboration projects considering each assessor's reliability. The gist of our proposed algorithm is that an assessor's reliability depends on the evaluation policy, and this reliability is evaluated by an analysis of variance of the scores assigned by the assessor. We also show that the proposed method is very efficient by case study in university class.

• 대한조선학회논문집
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• 제31권1호
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• pp.102-110
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• 1994

본 연구를 통하여 협대역 랜덤 기진모멘트 스펙트럼으로 표현되는 횡동요 기진 모멘트를 받는 선박의 횡동요 응답의 통계적 특성을 다중 시간법을 이용하여 그 결과를 구하고, 이를 등가선형화법으로 얻어진 결과와 비교해 보았다. 계산 결과, 등가선형화법보다 다중 시간법을 이용한 결과가 훨씬 넓은 다중치 영역을 보여주는 것을 알 수 있었다. 그리고 시간 궤적에서 횡동요 기진 모멘트의 시뮬레이션과 선박의 횡동요 운동의 시뮬레이션을 수행하여 그 결과를 확인하였다.

• Communications for Statistical Applications and Methods
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• 제28권2호
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• pp.151-159
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• 2021

In this article, our interest is to estimate the association between consecutive gap times which are subject to interval censoring. Such data are referred as doubly interval censored data (Sun, 2006). In a context of serial event, an induced dependent censoring frequently occurs, resulting in biased estimates. In this study, our goal is to propose a Kendall's 𝜏 based association measure for doubly interval censored data. For adjusting the impact of induced dependent censoring, the inverse probability censoring weighting (IPCW) technique is implemented. Furthermore, a multiple imputation technique is applied to recover unknown failure times owing to interval censoring. Simulation studies demonstrate that the suggested association estimator performs well with moderate sample sizes. The proposed method is applied to a dataset of children's dental records.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.114-118
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• 2021

In this research, the dimensional error of the measured specimen according to the measurement method was analyzed for the length, angle, radius of curvature and diameter using a projector which is used in industry. One-way analysis was performed on each data tested 30 times using a statistical technique. Through the experiment, it was found that an error occurred in each data when measuring the length and radius of curvature according to the measurement method, and the null hypothesis that no error occurred when measuring the angle and length was established. Based on this experimental data, the automatic measurement when measuring the projector causes less measurement error, so automatic measurement is recommended when measuring a small product. Also, an optimal measuring method is suggested for securing reliability on formulations of measurement automation.