• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.3
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• pp.195-202
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• 2015

NHPP software reliability models for failure analysis can have, in the literature, exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, finite failure NHPP models that assuming the expected value of the defect and infinite failures NHPP models that repairing software failure point in time reflects the situation, were presented for comparing property. Commonly used in the field of software reliability based on exponential power distribution software reliability model finite failures and infinite failures were presented for comparison problem. As a result, finite fault model is effectively infinite fault models, respectively. The parameters estimation using maximum likelihood estimation was conducted. In this research, software developers to identify software failure property some extent be able to help is considered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.952-962
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• 2015

In this study, multilayered rings with a large outer diameter have been developed using a hot ring rolling process. The ring rolling process has been analyzed by rigid plastic finite element analyses (FEA) using the AFDEX2D and AFDEX3D/HEXA/RING simulators, where the finite element meshes received severe plastic deformation are remeshed into a fine mesh-size using a dual-mesh system. According to the simulated results, the design variables of the multilayered rings were determined and real tests were conducted to check the validity of the simulation results. By adopting the hot ring rolling process, the input weight of raw materials was reduced by 40% against the conventional hot forging process and that the recovery rate was increased by 24%. The measurement of the averaged roundness was satisfied within 0.5 mm for both the inner and outer diameters. Moreover, the hot ring rolling processes yielded 1.49 Cpk for the outer-diameter and 0.84 Cpk 0.84 for the inner-diameter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2311-2318
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• 2007

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. Accurate predictions of software release times, and estimation of the reliability and availability of a software product require Release times of a critical element of the software testing process : test coverage. This model called Enhanced non-homogeneous Poission process(ENHPP). In this paper, exponential coverage and S-shaped model was reviewed, proposes the Kappa coverage model, which make out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE statistics and Kolmogorov distance, for the sake of efficient model, was employed. Numerical examples using real data set for the sake of proposing Kappa coverage model was employed. This analysis of failure data compared with the Kappaa coverage model and the existing model(using arithmetic and Laplace trend tests, bias tests) is presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.514-522
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• 2007

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this parer, Goel-Okumoto and Yamada-Ohba-Osaki model was reviewed, proposes the Burr distribution reliability model, which making out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE, AIC statistics and Kolmogorov distance, for the sake of efficient model, was employed. Analysis of failure using real data set for the sake of proposing shape parameter of the Burr distribution was employed. This analysis of failure data compared with the Burr distribution model and the existing model(using arithmetic and Laplace trend tests, bias tests) is presented.

• Korean Journal of Poultry Science
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• v.6 no.1
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• pp.12-23
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• 1979

This experiment was carrid out to investigate the interaction between boilelr strains and nutrition levels, and the performances of four broiler strains such as Han Hyup 603, Hubbard, Anak and Filch when they were fed by four different nutrition levels (High Protein and energy; HP. HE., Medium Protein and energy; MP. ME., Low Protein ana energy; LP. LE., and low protein and energy; LLP. LLE.). The data used in this study were obtained from a total of 1200 broiler type chicks in Poultry Testing Station, Korean Poultry Association from June 16, to August 11, 1978. Differences of all characters among four nutrition levels were significant except viability and carcass rate. HP. HE and MP. ME treatments showed nearly the same performances in body weight, feed efficiency and point, spread but they were significantly superior to those of LP. LE and LLP. LLE. There were not significant differences among four strains in feed efficiency and viability but other characters, body weight, point spread and carcass rate were observed that the performance of the best strain B was significantly superior to strain D but it was not recognized significance compared with strain A, C in tile result of statisticel analysis. In the interaction between strains and nutrition levels, body weight at high and levels showed significantly differences but at low and low nutrition levels were nearly same among four strains. Therefore this study demonstrated that comparision of body weights between strains should be performed at medium nutrition level or above. Also point spread calculated as index of body weight and feed efficiency was observed that strain B at low nutrition level is excellently higher than other strains and there were little differences at low nutrition level among all strains. It was found that ]it tie differences between performances of high arid medium levels seemed to be as the reason of high fat addition for energy source to high mutrition feed, and in general superior strain showed good performance at all the nutrition levels in$.$all characters but in body weight and point spread there were significantly different responses with different nutrition level, The most superior strain B among four strains earned the most profit per bird, Although performances of high and medium nutrition levels were nearly the same, medium nutrition level also showed the most profit because the feed cost of high nutrition level was higher than that of medium nutrition level.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.27-35
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• 2007

This study presents a non -prismatic beam element for modeling the elastic and inelastic behavior of the steel beam, which has the post-Northridge connections in steel moment frames that are subjected to earthquake ground motions. The elastic stiffness matrix for non-prismatic members with reduced beam section (RES) connection is in the closed-form. The plasticity model is of a discrete type and is composed of a series of nonlinear hinges connected by rigid links. The hardening rules can model the inelastic behavior for monotonic and random cyclic loading, and the effects of local buckling. Verification and calibration of the model are presented in a companion paper.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.56-60
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• 1993

We have investigated the dependence of the magnetization, anisotropy, coercivity, and Kerr rotation on the Fe concentration in FeCo/Pd multilayer thin films, where the Fe concentration in the FeCo sublayer varied between 0 and 100% with maintaining the same sublayer thickness of $2.5\;{\AA}$ FeCo and $10.5\;{\AA}$A Pd. The maximum saturation magnetization was observed at the Fe concentration of about 48at.% in the FeCo sublayer. Perpendicular magnetic anisotropy and coercivity of the FeCo/Pd multilayer thin film decreased monotonically with increasing the Fe con-centration. The Kerr rotation angle also decreased with increasing the Fe concentration and the amount of vari-ation was remarkably changed with decreasing the light wavelength.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.3
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• pp.170-175
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• 1991

In order to calculate reflection coefficients of surface waves due to underwater obstacles, the hybrid boundary integral equation method is used. Numerical results based on the linear element are verified to the exact solutions for a flat bottom. Reflection coefficient and transmission coefficients for a step are compared to Young's results and the results by EFEM (Kirby et al., 1987), in which reflection coefficients decrease to zero as the periods of incident waves decrease. Reflection coefficients for a sinusiodal hump located on a constant depth increase due to the interaction between humps.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.653-659
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• 2014

Computer simulation has been performed to optimize cold forging process of automotive LPI fuel filter housing. A mold and the test product have been manufactured considering the strain and load distribution during the cold forging process. Also, fuel flow simulation has been performed to analyze flow characteristics of existing model and new model. Simulation result shows that two models have equivalent pressure drop. Compared with the mass of existing product, raw material reduction of 16 g and 30.5 g has been achieved from the upper and lower housing, respectively. Total mass reduction of the new housing was 46.5 g. Leak test and internal pressure test have been performed to verify the safety standard and test results were satisfactory.

• Publications of The Korean Astronomical Society
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• v.6 no.1
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• pp.1-15
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• 1991

원반 및 해일로의 이중역 (two-zone) 모형을 바탕으로하여 나선은하의 화학적 진화 모형을 만들었다. 모형의 검증을 위하여 구체적인 수치계산을 수행하고 그 결과를 태양 부근에서 관측된 중원소 분포 등, 화학적 진화와 관련된 제반 관측 사실과 비교함으로써 은하계의 진화를 추론하였다. 모형의 수치계산 결과에 의하면 나선은하의 화학적 진화는 헤일로외 붕괴 과정과 별탄생율에 크게 의존하며, 원반의 초기질량함수와 별탄생율에 따라 서로 다른 양상을 보인다. 태양 부근 원반의 중원소 분포 등을 성공적으로 설명할 수 있는 진화 모형에서, 별탄생율은 가스의 질량 또는 표면밀도의 멱승에 비례하거나 시간에 따라 단조 감소하는 지수함수로써 표현되며, 초기질량함수는 헤일로에서는 다양한 형태의 함수 모두로써 가능하지만, 원반의 경우에는 시간에 따라 변화하는 질량함수를 채택하여야 한다. 우리 은하의 헤일로의 고속붕괴 모형에서는 시간에 따라 지수함수로 변화하는 별탄생율이 관측과 부하되지만, 반면 저속붕괴의 경우에는 가스 질량의 멱함수로 표현되는 별탄생율이 관측과 부합된다.