• The Korean Journal of Applied Statistics
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• v.25 no.3
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• pp.423-434
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• 2012

A two-sample test for equality of survival distribution is one of the important issues in survival analysis, especially for clinical and epidemiological research. With interval censored data, some testing methods have been developed. This study introduces some testing methods and compares them under various situations through simulation study. Based on simulation result, it provides some useful information on choosing the most appropriate testing method in a given situation.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.121-135
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• 2015

We consider testing equality of mean functions from two samples of functional data. A novel test based on the adaptive Neyman methodology applied to the Hotelling's T-squared statistic is proposed. Under the enlarged null hypothesis that the distributions of the two populations are the same, randomization methods are proposed to find a null distribution which gives accurate significance levels. An extensive simulation study is presented which shows that the proposed test works very well in comparison with several other methods under a variety of alternatives and is one of the best methods for all alternatives, whereas the other methods all show weak power at some alternatives. An application to a real-world data set demonstrates the applicability of the method.

• Communications for Statistical Applications and Methods
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• v.4 no.1
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• pp.317-325
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• 1997

Group testing is an efficient method to classify units from a population as infected or non-infected and useful in estimating the infection rate when the population infection rate is small. Upper bounds are the focus of interest in group testing, but has not been studied extensively. In this paper, the upper bound derived from the uniformly most powerful test is proposed and compared with the classical approachers, Thompson's and Bhattacharyya et al.'s methods.

• Communications for Statistical Applications and Methods
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• v.13 no.3
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• pp.787-794
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• 2006

In group testing, the test unit consists of a group of individuals and each group is tested to classify units from a population as infected or non-infected or estimate the infection rate. If the test group is infected, one or more individuals in the group are presumed to be infected. It is assumed in group testing that classification of group as positive or negative is without error. But, the possibility of false negatives as a result of dilution effects happens often in practice, specially in many clinical researches. In this paper, dilution effect models in group testing are discussed and estimation methods of infection rate are proposed when a dilution effect exists.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.216-223
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• 2016

Purpose: This paper suggests the procedure to enhance the reliability of the software of the medical device that is to cure, treat, diagnose, and prevent a disease or an abnormal health conditions. Methods: After test requirements are classified by the software requirements specification for safety and backgrounds, reliability assessment methods are suggested. Results: Verification and validation for function and safety can be performed whether the medical device software are implemented as intended. Conclusion: Procedure on the static analysis, unit test, integration test, and system test are provided for the medical device software.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.3
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• pp.73-81
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• 1998

In this paper, the necessity of developing effective nondestructive testing and monitoring techniques for the evaluation of structural integrity and performance is described. The evaluation of structural integrity and performance is especially important when the structures and subject to abrupt external forces such as earthquake. A prompt and extensive inspection is required over a large area of earthquake-damaged zone. This evaluation process is regarded as a part of performance-based design. In the paper, nondestructive testing and monitoring techniques particularly for concrete structures are presented as methods for the evaluation of structural integrity and performance. The concept of performance-based design is first defined in the paper followed by the role of evaluation of structures in the context of overall performance=based design concept. Among possible techniques for the evaluation, nondestructive testing methods for concrete structures using radar and a concept of using fiber sensor for continuous monitoring of structures are presented.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1297-1302
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• 2007

It is very important to evaluate the reliable deformational characteristics of soils not only in the analysis of geotechnical structures under working stress conditions as foundation in railroad or road system but also for the soil dynamic problems. Different testing techniques are likely to have different testing conditions as strain amplitude, stress level, loading frequency and number of loading cycles. The deformational characteristics of soils can be affected by these variables. In this paper, the effects on modulus of soils subjected to cyclic load were investigated. For the evaluation of deformational characteristics of soils subjected cyclic load, various testing such as TS, RC, TX, and FFRC tests were performed. It was shown that the modulus evaluated by various testing methods are comparable to each other fairly well when the effects of these factors were properly taken into account. For reliable evaluation, therefore, those effects on the modulus need to be considered, and measured values should be effectively adjusted to actual conditions where the soil is working.

• Journal of Acupuncture Research
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• v.26 no.5
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• pp.11-17
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• 2009

Objectives : The objectives of this study were to examine the specificity and the sensitivity of tenderness testing on the ear about the postpartum breast pain, and to improve the efficacy of the tenderness test. Methods : Thirty women who visited in the hospital for recuperating 2-14 days after childbirth participated in this study. They answered the questionnaire of the severity of breast pain and their auricular acupuncture points were tested by a long metal probe with round tip 1.1mm in diameter. We analyzed the relationship between auricular tenderness testing on mammary gland zone[CW6] and postpartum breast pain with validity and significance as grouping 8 diagnosis methods. Results : When we consider above 'moderate pain' or 'severe pain' in the auricular tenderness testing as a positive sign, and above 'evere pain' or 'very severe pain' in the self-reported breast pain score as a positive symptom, the diagnostic efficacy was highest. The sensitivity for tenderness testing was 0.62-0.75, and the specificity was 0.64-0.72, and the sensitivity and the specificity in the contralateral ear were a little higher than in the ipsilateral ear. Conclusions : These results suggest that auricular tenderness testing can be objectified clinically and be used in diagnosis.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.69-73
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• 2005

The failure of geogrids used for soil reinforcement application can be defined as an excessive creep strain which causes the collapse of slopes and embankments. Accordingly, the lifetime is evaluated as a time to reach the excessive creep strain using two accelerated creep testing methods, time-temperature superposition(TTS) and stepped isothermal methods(SIM). TTS is a well-accepted acceleration method to evaluate creep behavior of polymeric materials, while SIM was developed in the last ten years mainly to shorten testing time and minimize the uncertainty associated with inherent variability of multi-specimen tests. The SIM test is usually performed using single rib of geogrids for temperature steps of $14^{\circ}C$ and a dwell time of 10,000 seconds. However, for multi-ribs of geogrids, the applicability of the SIM has not been well established. In this study, the creep behaviors are evaluated using multi-ribs of polyester geogrids using SIM and TTS creep procedures and the newly designed test equipment. Then the lifetime of geogrids are predicted by analyzing the failure times to reach the excessive creep strains through reliability analysis.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.380-387
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• 2003