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The hazard and operability study (HAZOP) is a analysis technique used in the oil and gas industry (O&G) for identifying hazardous operations. Possible conditions outside the normal process are examined in detail and the consequences assessed. The HAZOP analysis help to identify the hazard work conditions by splitting the project into manageable sections, allowing the team to focus on specific...
To support development of more reliable software, AMSAA has developed a software reliability scorecard offered free of charge to department of defense employees and their contractors. The scorecard methodology provides a structured and transparent approach to assess and improve software reliability practices. AMSAA's new software reliability scorecard assesses seven key areas of software development...
When complex software-controlled systems are subject to both software and hardware FMEA, conclusions are often incorrect in areas where software and hardware failures affect each other. These analysis errors occur because software specialists generally do not analyze hardware and hardware specialists generally do not analyze software, a situation that often leads them to use educated guesses when...
This paper proposes a new modeling approach which can be applied to solve some practical reliability engineering problems when competing failure modes present, but only one or limited failures have occurred. This type of failure data cannot be modeled by traditional time-to-failure distributions. The new approach is derived from Weibayes method and provides a viable solution when reliability inference...
In this paper, the introduction, functioning and importance of constant fraction discriminator in nuclear field was studied. Furthermore, reliability and degradation mechanisms that affects the performance of output pulse with temperature and dose rates acts as input characteristics was properly explained and verified with the experiments. Accelerated testing was carried out to define the life testing...
The paper emphasizes prognostics that are derived from data currently available within or from electronic components, thus avoiding the need for additional sensors and extensive physical modification of systems and permitting immediate savings to be realized. Areas where this approach is particularly suitable include Semiconductor memories Data communications Initialization procedures Feedback control...
Microelectronics device reliability has been improving with every generation of technology whereas the density of the circuits continues to double approximately every 18 months. We studied field data gathered from a large fleet of mobile communications products that were deployed over a period of 8 years in order to examine the reliability trend in the field. We extrapolated the expected failure rate...
Electronic Systems Reliability Analysis is based on Failure Rates (FR), which is mostly predicted using physics of failures techniques. In fact, we assume that the “electronic design” is near to perfect, and that the FR is based only on the physical materials. However, based on field failures analysis, we have found that many failures actually occur due in large part to a poor design, and that this...
The availability estimation of photovoltaic (PV) systems has not been received great attention in the literature. Availability is important consideration in the life-cycle of such systems. This paper presents a methodology for estimating the availability of a photovoltaic system using Petri networks. Each component - module, wires and inverter - is detailed in Petri networks. In this paper, we simulate...
Communicating the likelihood and consequence of potential risks is critical in today's business environment. A comparison of the likelihood of several different potential events can provide insight to management about factors that, if left unchecked, may cause an unwanted scenario. One method utilized to calculate the likelihood of a risk being realized is the “One-out-of-X” measure. This high-level...
Fault analysis has been identified as a crucial step during the design process. Any complex design problem requires careful consideration of fault modes, fault mechanisms, propagation of faults, etc. The verification and validation efforts in complex systems design can be improved by modeling faulty behavior. This can be done by using a library of pre-constructed faulty behavior models. Currently,...
The paper presents a method for determining an optimal loading in series-parallel systems. The optimal loading is aimed at achieving the greatest possible expected system availability subject to required demand constraint. Then the corresponding system cost is deduced. We consider that system cost is a combination of downtime cost (loss of productivity), and repair cost (supposed proportional to repair...
Many present-day problems are multiobjective in nature and their solution requires consideration of conflicting objectives. Usually, they have a number of potentially Pareto-optimal solutions. An extensive knowledge of the problem is required in discriminating between solutions, eliminating the unwanted ones and accepting the required solution(s) by a decision making process.
This paper discusses a Reliability, Availability, and Maintainability (RAM) independent assessment conducted to support the refurbishment of the Compressor Station at the NASA Langley Research Center (LaRC). The paper discusses the methodologies used by the assessment team to derive the repair by replacement (RR) strategies to improve the reliability and availability of the Compressor Station (Ref...
The human operator as the basic postulate of events appearance of catastrophes and failures; however issuing finders of diverse currents have to apply different methods to minimize risks of human errors, some have used combined methods taking counts him personals factors and engineering, others himself are supported on estimations probabilities to calculate trials of workers.. Moreover, it is through...
The root cause of the difference between predicted reliability during DoD system development and achieved reliability in OT&E is “bad” reliability requirements being placed on contract, or misinterpreted/misapplied during development. This paper has identified the need for a more accurate and comprehensive approach to developing contractual reliability requirements that meet the end-users' operational...
This paper discusses the value of having a methodology and capability to de-risk the design from stress de-rating point of view and how to improve the bottom line by following and building enough margins in the design.
This paper introduces a new online system health monitoring methodology utilizing Bayesian Belief Networks. The developed methodology enables inference with limited number of monitoring points optimally placed to obtain information on functional states of components, subsystems, and relevant physical parameters affecting the reliability of elements of the system. The approach integrates physics of...
Accelerating Testing techniques can be used in the medical device industry as a tool to enhance device reliability, ensure patient safety, and comply with regulatory agency risk management requirements
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