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This paper explores development and comparative assessment of strategies to assist the reliability engineer in a competitive program scenario. The idea of using a methodology such as game theory has numerous beneficial aspects. At the very highest level, it brings structure to the competitive approach, which for the most part, is usually a process that is influenced by a variety of unstructured variants...
The importance of a business data cannot be understated. Custom-system builders protect vital data by building redundant technology into both servers and desktop workstations. The most common type of redundant technology is RAID. The term RAID is short for redundant array of independent (or inexpensive) disks. RAID is established when two or more hard disk drives are combined in a way to either increase...
Because railway locomotives are complex and highly correlated with each other among its components, it is difficult to make Criticality evaluation by using traditional methods. In the present work, a criticality evaluation index model of the locomotive is established and the Monte Carlo simulation method is employed to obtain the criticality priority of the railway locomotive components. Based on...
NASA and DLR (German aerospace center) have been working together to create the stratospheric observatory for infrared astronomy (SOFIA). SOFIA is a Boeing 747SP (Special Performance) aircraft extensively modified to accommodate a 2.5 meter reflecting telescope and airborne mission control system. This paper shows how the SOFIA program handled one safety issue through appropriate use of NASA's risk...
In the design of fatigue sensitive components, attention is often focused on defining a representative load spectrum that can be used with the fatigue properties of the material to assess the relative merits of a particular design. In practice, these techniques often employ conservative assumptions on the loads and large safety factors on the fatigue properties (e.g. S-N curve) to evaluate successful...
This article deals with modelling and analysis of the reliability of complex systems that use one-shot items during their operation. It includes an analysis of the impact of the reliability of used one-shot items on the resulting reliability of the system as a whole. Practical application of theoretical knowledge is demonstrated on an example of a model of reliability of an aircraft gun that was used...
The methodology proposed in this paper is illustrated for a particular failure mode that was observed in a recently developed product during accelerated life testing (ALT). The probabilistic simulation methodology applied in this paper is used to predict and improve the survivability of the product under repeated drop testing. The failure mode encountered is the cracking of magnesium housing under...
In modern complex systems such as chemical and nuclear plants, as its hardware system reliability increases due to the advancement of technology, systemic failures such as software design errors become a significant contributor to system accidents. In the software design of a protective system, not only its own performance, but also its interactions with other components must be considered. This paper...
Ad-hoc networking is used because of its malleable topology. The absence of infrastructure allows for the hasty deployment and redeployment of a network. No preparation of the coverage area is needed because things like transmission towers or communication wire lines are not necessary. It is this distinctive attribute of ad-hoc networking that does not conform to the base assumption on which all current...
Crash dummies have been used for many years to evaluate the safety and crash worthiness of automobiles and other vehicles. The dummies provide a way of measuring the ergonomics of the automobile's design and also the impact of a crash on the vehicle occupants. Personas serve the same purpose for software systems. A persona represents a certain type of user; however it goes beyond a user's physical...
In this research, Markov chain Monte Carlo (MCMC) method was used to derive posterior knowledge of accelerated life model parameters in a Bayesian inference framework. The concept is discussed through a case study considering the fatigue life of a mechanical component. In the first step a comprehensive model including the relationship among parameters, design variables, material properties and available...
We present a mathematical model for describing the relationship between overhead and error reduction under single-error conditions in combinational logic using N-modular redundancy (NMR) as an upper bound. We then provide an analysis for the model under more realistic circuit and overhead assumptions. We compare system, sub-circuit, and gate level NMR. Based on our results, implementing NMR at the...
This paper extends previous works developed for evaluating the security characteristics of a network system (e.g. for water supply, electric power or gas distribution) exposed to a terrorist "attack", by taking into account simultaneously several characteristics. Given a source node where the hazard is injected, two criteria are used to assess the vulnerability of the network: the time to...
Early prediction of software reliability can help organizations make informed decisions about corrective actions. To provide such early prediction, we propose practical methods to: 1) systematically identify defects in a software requirements specification document using a technique derived from cause-effect graphing analysis (CEGA); 2) assess the impact of these defects on software reliability using...
This paper describes the approach taken for the reliability analyses, including probabilistic risk assessments (PRAs), of the Lunar Reconnaissance Orbiter (LRO) that have been performed concurrently with the designs to identify problem areas and ensure corrective actions were taken in a timely manner. The LRO is a large system with more than 14,000 piece-parts and over 120 purchased or contractor-built...
Typical early failures and reliability of modern cordless mobile portable devices, characterized by their inability to provide quality RF performance, are analyzed. Multifaceted specifics of device technology, reliability and FA are discussed. Systematic analytical methodology is applied and RF-specific methods are outlined. Product and application statistics are displayed. Integrated block diagrams...
Reliability engineers and actuaries from the insurance industry are increasingly being asked to collaborate in measuring, valuing and managing risk associated with extended warranties and long term service agreements. This interaction has resulted in the development of hybrid approaches that combine methods of quantifying uncertainty in the engineering domain (probabilistic design algorithms) with...
Proper preventive maintenance of complex systems, such as those used for power generation and medical diagnosis is dependent on the availability of their up-to-date reliability models. These models are constructed from historical maintenance and fault information of the equipment. Due to the complex nature of these machines, constructing these models involves significant manual effort which limits...
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