• 한국신뢰성학회지:신뢰성응용연구
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• 제14권2호
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• pp.129-136
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• 2014

Reliability test is focusing to detect the unexpected reliability failure and solve them for the high quality of products. The test data should be used to assess and project the current level of interesting product reliability and so it is very important to have the accurately assessing methodology with test data. There are two type of trend for test data as constant and changing one during testing and this paper shows the difference in the assessing results of these two cases. There is less information how to define the existence of reliability growth rate changing and calculate the parameters of the reliability growth models to make an accurate assessment with such condition, so i established the process and mathematical model to calculate the parameters at such condition to make reliability growth curve with high Goodness of Fit. I validated the new method with the data made from Monte Carlo Simulation and case from Demko (1993). Even the assessed result with the new methodology may be different with the case by case because of very diversity in test condition and testing product quality, but the process and method founded in this research can be applied to any case using Duane and AMSAA model for their test data assessment. I also present the evaluation method to see the effectiveness with new one which is a conventional knowledge and not popular to use, so it is possible to compare the results with the newly presented and conventional method for better business decision.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1107-1113
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• 2015

Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

• 대한수학회지
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• 제50권4호
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• pp.879-897
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• 2013

Shannon entropy is one of the widely used randomness measures especially for cryptographic applications. However, the conventional entropy tests are less sensitive to the inter-bit dependency in random samples. In this paper, we propose new online randomness test schemes for true random number generators (TRNGs) based on the mutual information between consecutive ${\kappa}$-bit output blocks for testing of inter-bit dependency in random samples. By estimating the block entropies of distinct lengths at the same time, it is possible to measure the mutual information, which is closely related to the amount of the statistical dependency between two consecutive data blocks. In addition, we propose a new estimation method for entropies, which accumulates intermediate values of the number of frequencies. The proposed method can estimate entropy with less samples than Maurer-Coron type entropy test can. By numerical simulations, it is shown that the new proposed scheme can be used as a reliable online entropy estimator for TRNGs used by cryptographic modules.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1286-1291
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• 2004

This paper was showed evaluation method and technical items for measurement test of new catenary system of Honam(Daejeon - Mokpo) conventional railway electrified. This line have tested by three type new electric rolling stocks in order to test construction quality and operation safety of a new catenary system with speed-up than conventional speed. We have some important experiences through measurement test of catenary system by new device installed on train roof.

• 한국정보처리학회논문지
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• 제6권11호
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• pp.3086-3096
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• 1999

To declare conformance of multi-protocol Implementation Under Test(IUT), every layer of the multi-protocol IUT should be tested. According to ISO9646, single-layer test method is applied to testing the highest layer of multi-protocol IUT and single-layer embedded test method is used for the layers by layer all the protocols in a multi-protocol IUT. This paper proposes a new method for testing a multi-protocol IUT. The proposed test method assumes that a multi-protocol IUT is under test and that the interfaces between the layers cannot be controlled or observed by the tester. We apply the proposed test method to TCP/IP and compare the application results with those of the existing test turns out that the proposed test method significantly reduces the number of test cases as well as the number of test events while providing the same test coverage. In addition, the proposed test method shows the capability to locate the layer that is source of failure in testing multi-protocol IUTs.

• Radiation Oncology Journal
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• 제33권1호
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• pp.42-49
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• 2015

Purpose: In order to keep the acceptable level of the radiation oncology linear accelerators, it is necessary to apply a reliable quality assurance (QA) program. Materials and Methods: The QA protocols, published by authoritative organizations, such as the American Association of Physicists in Medicine (AAPM), determine the quality control (QC) tests which should be performed on the medical linear accelerators and the threshold levels for each test. The purpose of this study is to increase the accuracy and precision of the selected QC tests in order to increase the quality of treatment and also increase the speed of the tests to convince the crowded centers to start a reliable QA program. A new method has been developed for two of the QC tests; optical distance indicator (ODI) QC test as a daily test and gantry angle QC test as a monthly test. This method uses an image processing approach utilizing the snapshots taken by the CCD camera to measure the source to surface distance (SSD) and gantry angle. Results: The new method of ODI QC test has an accuracy of 99.95% with a standard deviation of 0.061 cm and the new method for gantry angle QC has a precision of $0.43^{\circ}$. The automated proposed method which is used for both ODI and gantry angle QC tests, contains highly accurate and precise results which are objective and the human-caused errors have no effect on the results. Conclusion: The results show that they are in the acceptable range for both of the QC tests, according to AAPM task group 142.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.308-309
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• 2018

This paper proposes new D/A(Digital to Analog) Design method for improving accuracy in high-performance test equipment. The proposed new D/A design can improve accuracy of the equipment even with low-resolution D/A converters. The validity of proposed D/A design is verified by analysis and experiment.

• 한국음향학회지
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• 제22권1호
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• pp.42-47
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• 2003

본 논문에서 제안하는 방법은 화자 확인 (speaker verification)에서 시퀀스 확률비 테스트 (SPRT: sequential probability ratio test)를 위한 시작 프레임의 샘플 시프트를 이용해서 새로운 테스트 데이터를 생성하는 방법이다. SPRT는 테스트 계산량을 줄일 수 있는 효과적인 알고리즘이다. 그러나 테스트의 결정과정에서 SPRT 방법은 입력신호가 확률밀도 함수로부터 독립적이고 균일하게 분포되어 있다는 가정하에 수행할 수 있으며, 또한 발성길이가 짧은 데이터에는 적용하기에 적절하지 못하다. 제안한 방법은 시작 프레임의 샘플 시프트를 통한 새로운 테스트 데이터를 생성하는 방법이기 때문에 테스트 데이터의 길이에 상관없이 SPRT를 수행할 수 있다. 또한 SPRT 방법에서 고려해야 하는 데이터의 상관성은 주성분 분석(principal component analysis)을 이용함으로써 효과적으로 제거하였다. 실험 결과 제안한 방법은 기존의 방법보다 샘플시프트를 위한 데이터의 계산량은 약간 증가하였지만, 등가오류율 (EER: equal error rate)에서 평균0.7%이상 좋은 성능결과를 보였다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제13권2호
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• pp.86-99
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• 2007

패킷 필터링이란 악의적인 네트워크 패킷들을 거르는 작업을 말한다. 패킷 필터링의 기능을 테스트하기 위해서는 구축된 보안 정책이 의도했던 대로 정확하게 동작하는가를 검증하여야 한다. 그러나 이런 기능을 테스트하기 위한 도구들은 많지 않으며, 테스트 과정에서 많은 사용자의 노력을 요구한다. 대부분의 보안 관리자들은 보안 정책을 새로 수립하거나 기존의 보안 정책을 수정할 때에 새로운 보안 정책을 체계적으로 테스트하는 것에 부담을 느낀다. 이런 부담을 경감해주기 위해 우리는 사용자의 참여를 최소화하는 새로운 테스트 방법을 제안한다. 제안하는 방법은 테스트 케이스와 테스트 오라클의 생성을 자동화한다. 자동으로 생성된 테스트 케이스는 테스팅 과정의 입력 요소를 선택해야 하는 고민을 덜어주며, 자동으로 생성된 테스트 오라클은 사용자의 도움 없이 테스트 결과에 대한 판단을 가능하게 한다. 우리의 테스트 방법을 구현한 테스트 도구는 테스트 수행의 전체 4단계 중 테스트 준비, 테스트 실행, 테스트 평가의 3단계에 걸쳐 테스트 자동화를 실현하고 있다. 이런 테스트 도구 위에서 테스팅을 수행하게 된다면 결과적으로 테스트 활동의 신뢰도를 보다 높게 향상시킬 수 있다. 이 논문은 우리의 테스트 방법과 테스트 도구의 설계 및 구현에 관한 내용을 기술한다.

• 한국초전도ㆍ저온공학회논문지
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• 제22권1호
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• pp.24-28
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• 2020

Heat leakage is an important parameter to reflect heat insulated performance of cryogenic vessel. According to the current standard requirements, it needs to measure the daily evaporation rate to indicate heat leakage. The test needs-over 24h after cryogenic vessel in heat equilibrium as standard required, therefore test efficiency is poor and new efficient method is required to cut test time. First of all, the volume of instantaneous evaporated gas and heat leakage are calculated by the current standard corresponding to the maximum allowable daily evaporation rate of cryogenic vessel. Depending on the relationship between real daily evaporation rate and maximum allowable daily evaporation rate of cryogenic vessel, we designed a new test method based on the pressure changes over time in cryogenic vessel to determine whether its heat insulated performance meets requirements or not. Secondly, the heat transfer process was analyzed in measurement of cryogenic vessel, and the heat transfer equations of whole system were established. Finally, the test was completed in four hours; meanwhile the heat leakage and daily evaporation rate of cryogenic vessel are calculated basing on test data.