• 품질경영학회지
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• 제34권1호
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• pp.20-26
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• 2006

In the fields of mechanical reliability application, "zero" or "zero or one" failure tests are most commonly used for demonstrating reliability of a product since they reduce test duration and/or sample size compared to other test methods that guarantees the same reliability of a product with a given confidence level or consumer's risk. The test duration of the "zero or one" failure test is longer than that of "zero" failure test but it has advantage of smaller producer's risk. In this paper a two-stage test is developed that compromises the "zero" and "zero or one" failure tests. The properties of the proposed two-stage test are investigated and the three test methods are compared using a numerical example.

• Corrosion Science and Technology
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• 제12권1호
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• pp.56-64
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• 2013

An Eectrolytic Corrosion(EC) test method was evaluated by the comparison with Copper Accelerated Acetic Salt Spray(CASS) and Neutral Salt Spray(SS) tests. Those methods were applied in order to evaluate corrosion resistance of Ni-Cr plated and Zn-plated Fe substrates. The correlations between results obtained by different test methods were investigated. Results showed that the electrochemical method such as the EC test method was superior to the conventional methods such as CASS and SS, in terms of the quantitative accuracy and the test-time span. Furthermore, the EC test method provided the useful means to estimate the initiation of corrosion of each layer by monitoring the rest potentials of the coated layers such as Ni, Cr, and Zn on Fe substrate. With regard to test time spans, the EC test provided the 78 times and 182 times faster results than the CASS test in cases of $Fe+5{\mu}m$ $Ni+0.5{\mu}m$ Cr and $Fe+20{\mu}m$ $Ni+0.5{\mu}m$ Cr respectively, while the EC test was 85 times faster results than the Salt Spray test in the case of $Fe+20g/m^2$ Zn. Therefore, the EC test can be the better method to evaluate the resistance to corrosion of coated layers than the conventional methods such as the SS test and the CASS.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8455-8460
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• 2016

Background: Poor participation rates are often observed in colorectal cancer (CRC) screening programs utilising faecal occult blood tests. This may be from dislike of faecal sampling, or having benign bleeding conditions that can interfere with test results. These barriers may be circumvented by offering a blood-based DNA test for screening. The aim was to determine if program participation could be increased by offering a blood test following faecal immunochemical test (FIT) non-participation. Materials and Methods: People were invited into a CRC screening study through their General Practice and randomised into control or intervention (n=600/group). Both groups were mailed a FIT (matching conventional screening programs). Participation was defined as FIT completion within 12wk. Intervention group non-participants were offered a screening blood test (methylated BCAT1/IKZF1). Overall participation was compared between the groups. Results: After 12wk, FIT participation was 82% and 81% in the control and intervention groups. In the intervention 96 FIT nonparticipants were offered the blood test - 22 completed this test and 19 completed the FIT instead. Total screening in the intervention group was greater than the control (88% vs 82%, p<0.01). Of 12 invitees who indicated that FIT was inappropriate for them (mainly due to bleeding conditions), 10 completed the blood test (83%). Conclusions: Offering a blood test to FIT non-participants increased overall screening participation compared to a conventional FIT program. Blood test participation was particularly high in invitees who considered FIT to be inappropriate for them. A blood test may be a useful adjunct test within a FIT program.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권1호
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• pp.25-28
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• 2018

Objectives: This study aimed to describe recent patterns in the types of statistical test used in original articles that were published in Journal of the Korean Association of Oral and Maxillofacial Surgeons. Materials and Methods: Thirty-six original articles published in the Journal in 2015 and 2016 were ascertained. The type of statistical test was identified by one researcher. Descriptive statistics, such as frequency, rank, and proportion, were calculated. Graphical statistics, such as a histogram, were constructed to reveal the overall utilization pattern of statistical test types. Results: Twenty-two types of statistical test were used. Statistical test type was not reported in four original articles and classified as unclear in 5%. The four most frequently used statistical tests constituted 47% of the total tests and these were the chi-square test, Student's t-test, Fisher's exact test, and Mann-Whitney test in descending order. Regression models, such as the Cox proportional hazard model and multiple logistic regression to adjust for potential confounding variables, were used in only 6% of the studies. Normality tests, including the Kolmogorov-Smirnov test, Levene test, Shapiro-Wilk test, and $Scheff{\acute{e}}^{\prime}s$ test, were used diversely but in only 10% of the studies. Conclusion: A total of 22 statistical tests were identified, with four tests occupying almost half of the results. Adoption of a nonparametric test is recommended when the status of normality is vague. Adjustment for confounding variables should be pursued using a multiple regression model when the number of potential confounding variables is numerous.

• 디지털융복합연구
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• 제10권11호
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• pp.485-491
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• 2012

대학생 72명의 사위검사에서 프리즘 분리법과 마독스 로드 검사법으로 측정되어진 수평사위 값의 차이를 알아보고자 하였다. 검사방법은 원거리 완전 교정 상태에서 프리즘 분리법, 마독스 로드 검사법의 두 가지 방법을 이용하였다. 프리즘 분리법에 의한 수평사위 검사에서는 정위 21명(29%), 외사위 36명(50%), 내사위 15명(21%) 이었다. 마독스 로드 검사법에 의한 수평사위 검사에서는 정위 36명(50%), 외사위 26명(36%), 내사위 10명(14%), 이었다. 두 검사의 평균값은 각각 프리즘 분리법 $0.93{\Delta}$ BI, 마독스 로드 검사법 $0.96{\Delta}$ BI이었다. 검사 방법에 따라 수평사위 값의 차이는 없었다. 또한 heterphoria 법으로 AC/A비를 측정한 결과 최저 1.0에서 최대 8.8까지 분포하고 있었으며, 대상안의 굴절이상 상태와는 유의하지 않았다.

• 대한토목학회논문집
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• 제32권4A호
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• pp.197-206
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• 2012

충돌해석 데이터의 확대해석 사례는 미국의 도로안전시설 지침인 MASH(Manual for Assessing Safety Hardware, AASHTO, 2009)에서 2,270 kg 픽업트럭의 충격흡수시설에 대한 충돌시험 데이터로부터 1,500 kg 중형승용차의 안전도를 계산하는 절차에 관한 내용을 최초로 소개하였다. MASH 방법에 따라 1.3 ton 차량의 충돌시험 데이터로부터 0.9 ton 차량의 충돌데이터 및 안전지수를 계산하여 0.9 ton 차량의 충돌실험 데이터와 비교하였다. 비교 결과 MASH방법으로 계산한 0.9 ton 차량의 충돌데이터 및 안전지수가 충돌실험 데이터와 큰 차이를 나타낸다는 것을 확인하였고 그 원인을 분석하여 새로운 확대해석 방법을 개발하였다. 개발된 확대해석 방법은 질량이 큰 차량(1.3 ton)의 충돌시험 데이터로부터 작은 차량(0.9 ton)의 충돌 데이터를 계산할 수 있을 뿐 아니라 작은 차량(0.9 ton)의 충돌 데이터로 부터 큰 차량(1.3 ton)의 데이터를 계산할 수 있다. 개발된 확대해석 방법은 정확도가 MASH에 비하여 월등하고 이론적인 원리가 확실하다. 본 논문은 충돌시험 데이터를 이용하여 새로운 확대해석 방법의 효율성과 정확도를 입증하고 그 원리를 규명하였다.

• 수산해양기술연구
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• 제18권2호
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• pp.77-80
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• 1982

총톤수 240 톤급 가다랑어 채낚기 어선의 조종성능을 연구하기 위하여, 실선에 의한 Z실험을 행한 결과를 요약하면 다음과 같다. 1. $10^{\circ}$Z실험에서의 선회성지수 K'는 0.611, 추종성지수 T'는 1.094, 20$^{\circ}$Z시험에서의 K'는 0.622, T'는, 1.695, 30$^{\circ}$Z시험에서 K'는 1.367로서 추종성은 $10^{\circ}$타각, 선회성은 20$^{\circ}$타각을 사용할 때 가장 좋으며, 전체적으로는 $10^{\circ}$의 소타각을 사용할 때의 조종성능이 20$^{\circ}$, 30$^{\circ}$의 대타각을 사용할 때 보다 더 양호하다는 것을 알 수 있다. 2. 조종성지수 K' 및 T'가 다른 종류의 선박들의 그것과 비교하여 작으므로, 추종성은 양호하나 선회성은 나쁘다는 것을 알 수 있다. 3. $10^{\circ}$Z시험에서의 1조작간 항주거리인 5~11배 이내이므로 종합적으로는 조종성능이 양호하다고 볼 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.335-342
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• 2000

In this study, the swelling characteristics of reconstituted clayey soil were investigated by STD and CRS test. The strain rate during loading was constant i.e. 0.05 %/min, 0.03 %/min and during unloading was varied in proportion to 1/1, 1/5, 1/10 and 1/15 of strain rate during loading. From this study the following conclusions were obtained; (1) There were similar values, especially, during unloading in case of 1/10 or 1/15 of strain rate during loading and the test results between STD and CRS were much to be alike. (2) The cross point of effective stress versus excess pore water pressure ratio curve, was increased during unloading, while the stress level of the cross point was decreased. The stress level can be separated into two zones according to the swelling index named Cs1 and Cs2. From the test results, the values of Cs1 were approximately constant irrespective of strain rate during unloading, but the values of Cs2 were much influenced by strain rate. (3) In CRS consolidation tests, it was found that unloading strain rate did not affect on the existence of zone.

• 한국지역사회생활과학회지
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• 제26권4호
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• pp.633-645
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• 2015

This study investigates the genotoxicity of crude antifungal compounds produced by Lactobacillus plantarum AF1 (L.plantarum AF1) and Lactobacillus plantarum HD1 (L. plantarum HD1) isolated from kimchi. The genetic toxicity of crude antifungal compounds was evaluated in bacterial reverse mutation in Salmonella and Escherichia spp., chromosome aberrations in Chinese hamster lung cells, and micronucleous formations in mice. In bacterial reversion assays with Salmonella Typhimurium TA98, TA100, TA1535, TA1537, and WP2uvrA, crude antifungal compounds did not increase the number of revertant colonies in both the absence and presence of the 59 metabolic activation system. In the chromosome aberration test with Chinese hamster lung cells, crude antifungal compounds showed no increase in the frequency of chromosome aberrations in the short-period test with/without the S9 mix or in the continuos test. In the in vivo mouse micronucleus assay, crude antifungal compounds showed no increase in the frequency of polychromatic erythrocytes with micronuclei. The results show that crude antifungal compounds produced by L. plantarum AF1 and L. plantarum HD1 did not induce any genotoxicity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1391-1393
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• 2008

In this paper, the long-term reliability for 1.25G transceiver in use of high speed optical access network is investigated. High temperature storage tests and accelerated life tests are used to long-term reliability. Accelerated aging test have been during 3,000 hour of the three accelerated aging conditions by caused high temperature stress. Mean life is assumed to follow the Arrhenius relationship and analysis from the failure data obtained in the accelerated aging conditions.