• International Journal of Reliability and Applications
• /
• 제10권1호
• /
• pp.17-32
• /
• 2009

The aim of this work is to generalize reliability equivalence technique to apply it to a system consists of n independent and non-identical components connected in series system, that have mixing constant failure rates. We shall improve the system by using some reliability techniques: (i) reducing some failure rates; (ii) add hot reduncy components; (iii) add cold reduncy components; (iv) add cold reduncy components with imperfect switches. We start by establishing two different types of reliability equivalence factors, the survival equivalence (SRE), and mean reliability equivalence (MRE) factors. Also, we introduced some numerical results.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제11권2호
• /
• pp.141-149
• /
• 2011

Environment Conversion Factors, which are stipulated in System Reliability Toolkit, have a lot of advantages once applied in a reliability data handbook such as NPRD-95, during the process of reliability prediction. However, the factors have a restriction in their applications because they don't deal with a few environments, e.g., Missile Launch (ML). In this study, environment factors of various components from MIL-HDBK-217F were analyzed to address this problem. Statistical computations showed that converting from Airborne Rotary Wing (ARW) to Missile Launch (ML) was the most coherent by comparing coefficient of determination. In addition, conversion factors from System Reliability Toolkit and those from the statistical calculations were evaluated in terms of their similarities.

• Safety and Health at Work
• /
• 제7권3호
• /
• pp.194-200
• /
• 2016

Background: The influence of sociocultural factors on human reliability within an open sociotechnical systems is highlighted. The design of such systems is enhanced by experience feedback. Methods: The study was focused on a survey related to the observation of working cases, and by processing of incident/accident statistics and semistructured interviews in the qualitative part. In order to consolidate the study approach, we considered a schedule for the purpose of standard statistical measurements. We tried to be unbiased by supporting an exhaustive list of all worker categories including age, sex, educational level, prescribed task, accountability level, etc. The survey was reinforced by a schedule distributed to 300 workers belonging to two oil companies. This schedule comprises 30 items related to six main factors that influence human reliability. Results: Qualitative observations and schedule data processing had shown that the sociocultural factors can negatively and positively influence operator behaviors. Conclusion: The explored sociocultural factors influence the human reliability both in qualitative and quantitative manners. The proposed model shows how reliability can be enhanced by some measures such as experience feedback based on, for example, safety improvements, training, and information. With that is added the continuous systems improvements to improve sociocultural reality and to reduce negative behaviors.

• Geomechanics and Engineering
• /
• 제6권2호
• /
• pp.99-115
• /
• 2014

Uncertainties in design variables and design equations have a significant impact on the safety of geotechnical structures like retaining walls and slopes. This paper presents a possible framework for obtaining the partial safety factors based on reliability approach for different random variables affecting the stability of a reinforced concrete cantilever retaining wall and a slope under static loading conditions. Reliability analysis is carried out by Mean First Order Second Moment Method, Point Estimate Method, Monte Carlo Simulation and Response Surface Methodology. A target reliability index ${\beta}$ = 3 is set and partial safety factors for each random variable are calculated based on different coefficient of variations of the random variables. The study shows that although deterministic analysis reveals a safety factor greater than 1.5 which is considered to be safe in conventional approach, reliability analysis indicates quite high failure probability due to variation of soil properties. The results also reveal that a higher factor of safety is required for internal friction angle ${\varphi}$, while almost negligible values of safety factors are required for soil unit weight ${\gamma}$ in case of cantilever retaining wall and soil unit weight ${\gamma}$ and cohesion c in case of slope. Importance of partial safety factors is shown by analyzing two simple geotechnical structures. However, it can be applied for any complex system to achieve economization.

• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.801-813
• /
• 2023

The events at Three Mile Island in the United States brought about fundamental changes in the ways that simulation would be used in nuclear operations. The need for research simulators was identified to scientifically study human-centered risk and make recommendations for process control system designs. This paper documents the human factors research conducted at the Human Systems and Simulation Laboratory (HSSL) since its inception in 2010 at Idaho National Laboratory. The facility's primary purposes are to provide support to utilities for system upgrades and to validate modernized control room concepts. In the last decade, however, as nuclear industry needs have evolved, so too have the purposes of the HSSL. Thus, beyond control room modernization, human factors researchers have evaluated the security of nuclear infrastructure from cyber adversaries and evaluated human-in-the-loop simulations for joint operations with an integrated hydrogen generation plant. Lastly, our review presents research using human reliability analysis techniques with data collected from HSSL-based studies and concludes with potential future directions for the HSSL, including severe accident management and advanced control room technologies.

• International Journal of Reliability and Applications
• /
• 제5권4호
• /
• pp.115-128
• /
• 2004

Reliability of a power supply timber pole depends on complex combination of age, environmental factors involved in deterioration process ans inspection and maintenance actions influencing reliability and safety. In this paper soil and human factors are identified, models have been developed and analyzed for optimal maintenence decisions related to electrical power supply timber poles.

• International Journal of Reliability and Applications
• /
• 제10권1호
• /
• pp.43-57
• /
• 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.

• 전산구조공학
• /
• 제5권4호
• /
• pp.113-124
• /
• 1992

토목구조물 설계에 있어서 가장 보편적으로 사용되고 있는 도로교에 대한 하중계수에 기초한 최적신뢰성해석모델을 제안하고, 또 총기대비용 최소화원칙에 기인한 최적하중-저항계수 및 최적 공칭안전율에 대한 이론적 근거를 제시하는 것이 본 연구의 주요내용이다. MFOSM과 AFOSM을 포함하는 주요 2차 모멘트신뢰성 이론을 비교분석함으로써 AFOSM의 근사식과 대수정규포근사식을 본 연구에서 제안하는 최적신뢰성 및 설계규준의 유도에 사용함이 적절하다는 것을 알 수 있었다.

• 한국마이크로전자및패키징학회:학술대회논문집
• /
• 한국마이크로전자및패키징학회 2007년도 SMT/PCB 기술세미나
• /
• pp.115-127
• /
• 2007

[ ${\blacktriangleright$ ] Various Factors to affect TC Reliability of 4 array RES has been Investigated through Simulation Tool and Daisy Chain Board Test ${\blacktriangleright$ Solder Joint Crack Mechanism of 4 array RES has been Examined Also, It has been Examined Thoroughly What Influence Each Factors gibes to TC Reliability and Why Those Factors gives an Influence to it ${\blacktriangleright$ BGA Type RES is Suggested to Improve TC Reliability (Patented) ${\blacktriangleright$ Through this Study, Best Design Parameter has been Optimized to Increase TC Reliability of 4 Array RES

• 동의생리병리학회지
• /
• 제26권1호
• /
• pp.88-97
• /
• 2012

DSOM(Diagnosis System of Oriental Medicine), questionnaire for oriental medical(medicine) diagnosis is an online survey system containing 152 questions for female, 149 questions for male that asking the basic symtoms of 16 pathogenic factors(病機). The result of DSOM denotes reliability according to the level of major symptoms of each pathogenic factor. Standard level of reliability is equal to all 16 pathogenic factor basically except phlegm(痰). In case of phlegm(痰) we give different weight depending on whether the factor includes gray color under the orbit(痰飮氣) or not. To examine reliability of DSOM, statistical analysis has been done to the data of felmale 10101, male 1564 except for bad responses and stored between 1st April 2000 to 3rd June 2011. Based on the study, the conclusions were as follows. Reliability of DSOM. For female, all pathogenic factors showed over 85% confidence level except for phlegm 82.6%. For male, all pathogenic factors showed more than 90% confidence level except two factors, phlegm(痰) indicates 87.% and damp(濕) indicates 89.8%. HH rates among pathogenic factors were more than 50 points. For female, HH rates of other 14 pathogenic factors were all over 80% except for heat(熱) 78.2% and insufficiency of Yang(陽虛) 75.3%. For male HH rates of all pathogenic factors were more than 80% except HH rates of heat 78.2% and damp 77.8%. Research based on a degree of satisfaction of reliability derived from pathogenic factors with scores of HH results in for all 16 pathogenic factors showed over 85% of relatively high level of satisfaction for both sexes whose reliability standard come under 5~4 points. Comparing appearance frequency of pathogenic factors for both sexes. Male only displays higer than female in heat(熱). Whereas female were higher than male for other 15 pathogenic factors and the difference was biggest in heart(心) and least in insufficiency of Yin(陰虛). Comparing appearance frequency order of pathogenic factors for both sexes. Female outdistanced male in blood stasis(血瘀) coldness(寒) blood-deficiency(血虛) phlegm(痰), while male outdistance female in heat(熱) insufficiency of Yin(陰虛) deficiency of qi(氣虛). Male had lower average of each pathogenic factors than female except heat(熱) as well as deficiency of qi(氣虛).