• Title/Summary/Keyword: equivalence factor

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Reliability Equivalence of Two Non-identical Components

  • Mustafa, A.
    • International Journal of Reliability and Applications
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    • v.9 no.1
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    • pp.79-93
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    • 2008
  • The aim of this work is to generalize reliability equivalence techniques to apply them to a system consists of two independent and non-identical components connected in series(parallel) system, that have constant failure rates. We shall improve the system by using one component only. We start by establishing two different types of reliability equivalence factors, the survival reliability equivalence (SRE) and mean reliability equivalence (MRE) factors. Our second studies, introducing some applications for our studies in airports and our life. Also, we introduced some numerical results.

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Reliability Equivalence Factors of n-components Series System with Non-constant Failure Rates

  • Mustafa, A.
    • International Journal of Reliability and Applications
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    • v.10 no.1
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    • pp.43-57
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    • 2009
  • In this article, we study the reliability equivalence factor of a series system. The failure rates of the system components are functions of time t. we study two cases of non-constat failure rates (i) weibull distribution (ii) linear increasing failure rate distribution. There are two methods are used to improve the given system. Two types of reliability equivalence factors are discussed. Numerical examples are presented to interpret how one can utilize the obtained results.

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Reliability Equivalence Factors of a Series - Parallel System in Weibull Distribution

  • El-Damcese, M.A.;Khalifa, M.M.
    • International Journal of Reliability and Applications
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    • v.9 no.2
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    • pp.153-165
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    • 2008
  • This paper discusses the reliability equivalences of a series-parallel system. The system components are assumed to be independent and identical. The failure rates of the system components are functions of time and follow Weibull distribution. Three different methods are used to improve the given system reliability. The reliability equivalence factor is obtained using the reliability function. The fractiles of the original and improved systems are also obtained. Numerical example is presented to interpret how to utilize the obtained results.

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Study on Flame Stability Using a Slot Burner (슬롯버너를 이용한 예혼합화염의 안정성에 관한 연구)

  • Lee, Won-Nam;Seo, Dong-Kyu
    • 한국연소학회:학술대회논문집
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    • 2001.11a
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    • pp.97-103
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    • 2001
  • The characteristics of flame stability have been studied experimentally using a slot burner. The blowout conditions of a fuel-lean premixed laminar flame, which is located in the middle of fuel-rich premixed laminar flames, are identified for propane, ethylene, and methane flames. The fuel-rich flames could stabilize the fuel-lean flame for the equivalence ratio as low as 0.2. The laminar flame speed along with the heat release rate is likely to be the important factor in stabilizing a fuel-lean flame. The increase of heat release rate on a fuel-rich flame lowers the equivalence ratio limit for the stable fuel-lean flames. The stability of fuel-lean flames, however, was not sensitive to the equivalence ratio of a fuel-rich flame.

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The Effect of Biological Equivalence Examination on Prescribing Practice of Doctors (글리메피라이드 제제의 생물학적동등성 시험이 의사의 처방전발행에 미치는 영향)

  • Jang, Mal-Sook;Choi, Byung-Chul;Yong, Chul-Soon;Choi, Han-Gon;Rhee, Jong-Dal;Yoo, Bong-Kyu
    • Korean Journal of Clinical Pharmacy
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    • v.16 no.2
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    • pp.96-100
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    • 2006
  • Korea Food and Drug Administration (KFDA) has been expediting the Biological Equivalence Examination (BEE) project to encourage generic substitution without expense of inappropriate therapeutic outcome. However, little is known about which considerations are most important in making the decision to prescribe a drug among many generic drugs. The purpose of this survey was to identify how strongly the KFDA certification of BEE influenced doctors when they make a choice between brand and generics of glimepiride preparations. Telephone survey was performed towards doctors working at local clinics by using a questionnaire. Most influential factor to doctors' decision was drug cost followed by pharmaceutical representatives, therapeutic efficacy, and review guideline for reimbursement. Advertisement of the drug was the least influential followed by KFDA certification of BEE. The meaning of BEE was best understood by relatively young doctors with specialty in surgical parts. This survey result further indicated that the doctors considered the therapeutic equivalence examination a preferred measure to expedite generic substitution.

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Evaluation of Peak Overpressure and Impulse Induced by Explosion (폭발에 따른 최대과압 및 충격량 평가)

  • Yoon, Yong-Kyun
    • Explosives and Blasting
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    • v.34 no.4
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    • pp.28-34
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    • 2016
  • Empirical model, phenomenological model, and CFD model have been used to evaluate the blast effects produced by explosion of explosives, flammable gas and liquid or dust. TNT equivalence method which is one of empirical models has been widely used as it is simple. In this study, new peak overpressure-scaled distance and scaled impulse-scaled distance equations are induced through fitting data from the curves given by TNT equivalence method. If the TNT equivalent mass is calculated, it is possible to estimate the peak overpressure and impulse using the regression equations. Differences of peak overpressure with yield factor which is a component of TNT equivalence method are found to be great in near-by distances from explosion source where the increase in overpressure is very steep, but the differences are getting smaller as the distances increase.

A Study of NO Formation Characteristics in Laminar Flames Using 2-D LIF Technique (2-D LIF를 이용한 층류화염의 NO 생성특성에 관한 연구)

  • Lee, Won-Nam;Cha, Min-Suk;Song, Young-Hoon
    • Journal of the Korean Society of Combustion
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    • v.8 no.3
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    • pp.38-48
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    • 2003
  • OH, CH and NO radical distributions have been measured and compared with the numerical analysis results in methane/air partially premixed laminar flames using 2-D LIF technique. The pick intensity of OH LIF signal is insensitive to fuel equivalence ratio: however, CH LIF intensity decreases as equivalence ratio increases and the NO concentration increases with equivalence ratio. The contribution of the prompt NO, formed near premixed reaction zone, to the total NO formation is evident from the OH, CH, and NO PLIF images in which the dilution effect of nitrogen is minimal for the highest equivalence ratio. Measured OH and NO LIF signals in counterflow flames agree with the computed concentration distributions. Both numerical and experimental results indicate that the structural change in a flame alters the NO formation characteristics of a partially premixed counterflow flame. The nitrogen dilution also changes flame structure, temperature and OH radical distributions and results in the decreased NO concentrations in a flame. The levels of decrease in NO concentrations, however, depends on the premixedness(${\alpha}$) of a flame. The larger change in the flame structure and NO concentrations have been observed in a premixed flame(${\alpha}=1.0$), which implies that the premixedness is likely to be a factor in the dilution effect on NO formation of a flame.

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Improved nodal equivalence with leakage-corrected cross sections and discontinuity factors for PWR depletion analysis

  • Lee, Kyunghoon;Kim, Woosong;Kim, Yonghee
    • Nuclear Engineering and Technology
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    • v.51 no.5
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    • pp.1195-1208
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    • 2019
  • This paper introduces a new two-step procedure for PWR depletion analyses. This procedure adopts the albedo-corrected parameterized equivalence constants (APEC) method to correct the lattice-based raw cross sections (XSs) and discontinuity factors (DFs) by accounting for neutron leakage. The intrinsic limitations of the conventional two-step methods are discussed by analyzing a 2-dimensional SMR with the commercial DeCART2D/MASTER code system. For a full-scope development of the APEC correction, the MASTER nodal code was modified so that the group constants can be corrected in the middle of a microscopic core depletion. The basic APEC methodology is described and color-set problems are defined to determine the APEC functions for burnup-dependent XS and DF corrections. Then the new two-step method was applied to depletion analyses of the SMR without thermal feedback, and its validity was evaluated in terms of being able to predict accurately the reactor eigenvalue and nodal power profile. In addition, four variants of the original SMR core were also analyzed for a further evaluation of the APEC-assisted depletion. In this work, several combinations of the burnup-dependent and -independent XS and DF corrections were also considered. The results show that the APEC method could enhance the nodal equivalence significantly with inexpensive additional costs.

A Bayes Test for Equality of Intra-Subject Variabilities in 2$\times$2 Crossover Design

  • Oh, Hyun-Sook
    • Communications for Statistical Applications and Methods
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    • v.7 no.2
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    • pp.541-548
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    • 2000
  • Various statistical methods for assessment of equivalence in average bioavailabilities have been developed under the assumption that the intra-subject variabilities for the test and reference formulations are the same. Without the assumption, assessing the equivalence in average bioavailabilites does not imply that the two formulations are therapeutically equivalent and exchangeable. The most commonly used test procedure for equality of variabilites in 2$\times$2 crossover experiment is the so called Pitman-Morgan's adjusted F test based on the model without carryover effects (Chow and Liu(1992)). In this paper, a Bayesian method based on the Intrinsic Bayes Factor is proposed, which can be applied to the model with carryover effects.

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