• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.597-600
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• 2003

The development and maintenance of a sound bond are an essential requirements of concrete repair and replacement. The bond property of a bonded overlay to its substrate concrete during the lifetime is one of the most important performance requirements which should be quantified. A standard or a verified bond strength measurement method is required at field for screening, selecting materials and quality control for overlay or repair materials. This study compares the nipple pipe direct tensile test, flexural adhesion test, and core pull-off test with their test results. Substantial differences in the failure stresses of three test methods were attributed to their different geometries and loading conditions. From these comparison and investigation, core pull-off test was relatively good because the coefficient of variation values were about 2%. It would be suitable for use in-situ because of its simplicity and accuracy.

• Journal of the Korean Statistical Society
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• 제25권3호
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• pp.347-358
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• 1996

A new test for goodness-of-fit is presented. It is a modification of a test of LaRiccia (1991). These tests are applicable to continuous lo-cation/scale models. The new test statistic is based on a few selected order statistics taken from the sample, while the LaRiccia test is based directly on the full sample. Each test embeds the hypothesized model in a larger linear model and proceeds to test the goodness-of-fit hy-pothesis by testing the coefficients of this linear model appropriately. The general theory is presented. The tests are compared via computer simulation to a related test of Ali and Umbach (1989) for distributions that could be used as lifetime models. An important aspect of all these tests is that only standard $X_2$ tables are used. Selection of the spacings of the order statistics is discussed.

• Journal of Applied Reliability
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• 제13권1호
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• pp.1-10
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• 2013

A Bayesian zero-failure reliability demonstration test method for products with exponential lifetime distribution is presented. Beta prior distribution for reliability of a product is used to design the Bayesian test plan and selecting a prior distribution using a prior test information is discussed. A test procedure with zero-failure acceptance criterion is developed that guarantees specified reliability of a product with given confidence level. An example is provided to illustrate the use of the developed Bayesian reliability demonstration test method.

• Journal of Applied Reliability
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• 제2권1호
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• pp.1-14
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• 2002

High temperature operating test, temperature humidity test and temperature cycling were performed at various test levels for solid aluminum electrolyte capacitors made by domestic manufacturing company and foreign advanced manufacturing company. It was found that main failure mode of solid aluminum electrolyte capacitors was the decrease of their capacitances. The decrease of their capacitances has the same pattern in these tests. Test result for comparison of characteristics between domestic products and foreign advanced products shows that domestic products have the shorter lifetime and their capacitances decrease more rapidly in high temperature operating test and temperature humidity test. Also in these tests, accelerated tests for high temperature operating test and temperature humidity test were developed.

• International Journal of Reliability and Applications
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• 제2권3호
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• pp.189-197
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• 2001

The estimation of mean lifetimes in presence of interval censoring with mixed replacement procedure is examined when the distributions of lifetimes are exponential. It is assumed that, due to physical restrictions and/or economic constraints, the number of failures is investigated only at several inspection times during the lifetime test; thus there is interval censoring. The maximum likelihood estimator is found in an implicit form. The Cramor-Rao lower bound, which is the asymptotic variance of the estimator, is derived. The estimation of mean lifetimes for competing failures model has been expanded.

• The Korean Journal of Applied Statistics
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• 제12권2호
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• pp.463-478
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• 1999

가속수명시험은 제품의 사용조건 보다 높은 스트레스 수준에서 시험하여 제품의 신뢰수명을 추정하는 것으로써 스트레스 수준을 일정하게 유지하는 일정형 시험이 일반적이다. 그러나 경우에 따라서는 시험절차의 편리와 시험기간의 단축을 위해서 스트레스를 시간에 따라 선형적으로 증가시키는 램프(ramp)형 시험을 사용하기도 한다. 이 논문에서는 일정스트레 s에서 제품의 수명이 모수 $\Theta$(s), $\beta$인 와이블분포를 따르고 수명과 스트레스의 관계가 역거듭제곱모형인 경우에 스트레스를 사용조건에서 가하고, 스트레스 수준의 최대 한계가 주어져 있는 램프시험 하에서 시험제품이 갖는 수명분포를 유도하고, 정시관측중단시험의 경우에 대해서 수명분포의 최우추정량과 추정량의 점근분포를 구하며, 최우추정치를 구하는 알고리즘을 제안한다.

• Journal of the Korea Computer Industry Society
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• 제5권9호
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• pp.1079-1088
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• 2004

Generally, the code motion algorithm accomplishes the run-time optimal connected with the computational optimifation and the register overhead This paper proposes a sparse code motion, which considers the code size, in addition to computational optimization and lifetime optimization. The BCM algorithm carries out the optimal code motion computationally and the LCM algorithm reduces the register overhead in a sparse code motion algorithm. A sparse code motion algorithm is optimum algorithm computationally and lifetime because of suppression unnecessary code motion This algorithm improves runtime and efficiency of the program than the previous work through the performance test.

• Journal of Korean Institute of Industrial Engineers
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• 제20권1호
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• pp.15-25
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• 1994

The Bayesian approach to reliability acceptance sampling has several advantages over the non-Bayesian approach. For instance, the former usually requires less amount of testing time and smaller sample sizes than the latter. In this article, a Bayesian acceptance sampling plan(ASP) based on a failure-free period life test is developed under the assumption of exponential lifetime distribution, and is compared with the corresponding Bayesian hybrid ASP in terms of the expected completion time. It is found that the proposed ASP tends to have a smaller expected completion time than the Bayesian hybrid ASP as the prior assessment of the reliability of a lot becomes optimistic, and vice versa. Tables of failure-free period Bayesian ASP's are also included.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1108-1111
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• 2007

OLED driving voltage shift can reduce the OLED display lifetime, especially for digitally driven AMOLED. By operating OLED at high frequency, we were able to suppress OLED voltage shift degradation, expecting improved AMOLED lifetime. We describe frequency dependence of voltage shift obtained from bias stress test of OLED.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.481-484
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• 2008

In order to reduce IR drop through common electrode in AMOLED, we propose a novel method to form electrical contact between highly-conductive bus lines and common electrode by using a plasma-assisted patterning of OLED layers and double deposition of the common electrode. Plasma-assisted patterning effects on OLED performance and degradation have been investigated. This patterning method caused turn-on voltage decrease, current flow increase at the same applied OLED voltages, quantum efficiency decrease, and rapid degradation at early stage during the lifetime test. However, comparable 70% luminance lifetime were obtained for both patterned and non-patterned OLEDs.