Product Of Reliability Research Articles

Reliability Assessment for a Spacecraft Landing Buffer Mechanism Based on Small Sample Data

The landing buffer mechanism (LBM) is a crucial component of aerospace landing explorations, determining the success of the entire mission. Reliability demonstration tests (RDTs) are required to ensure the LBM’s performance meets the design index. However, the RDTs of the LBM often encounter limited samples and zero-failure data, making traditional binominal test programs and reliability assessment methods based on the maximum likelihood theory unsuitable. This paper introduces a novel small-sample test verification method for the LBM, which transforms traditional binominal tests into more informative metrological tests by measuring the buffer strokes of the LBM’s subsystems. Furthermore, a confidence limit theory for the product of subsystem reliability is developed in conjunction with the reliability series model of the LBM. This theory can use the measurement data of subsystems to assess the confidence limit of the LBM’s reliability. An actual engineering application demonstrates that the proposed method can effectively handle zero-failure data and verifies that the LBM’s reliability exceeds 0.9999 with a confidence of 0.9.

Systemic analysis of a manufacturing process based on a small scale bakery.

The main aim of the article is to present two new innovative concepts of reliability of a functioning manufacturing system in the process of making bread in small-scale bakeries. Reliability is understood as one of the representations of an operator acting on specific streams in time to to t. One of these represents the global reliability of a system as a function of parallel action of all the streams of the system in time to to t and is denoted as Pg(t). The second representation of reliability is a scalar value, Pss It shows a new function of global reliability of a manufacturing process as a product of system stream reliability. In order to plot the flow of the manufacturing process’s global reliability function, we need to perform detailed calculations, computations, and analysis of the differences of individual values in real time, as well as plan an algorithm of the flow of system streams. This needs a lot of effort, translating however, to a detailed picture of the process. In the analysed example, measurements and research revealed an important increase of the value of reliability in a transition from a traditional to a robotised bakery. The article also presents a new concept of the reliability of a technological process, based on the analysis of relations of elements of the following streams: energy, matter, information, time, and finances. It shows the method of specifying streams and the method for defining the reliability of important and supportive relations. Important relations between stream elements are defined as having the reliability value of one in time. Supportive relations bear the reliability within a continuum between zero and one. Important relations are designated based on research, experience, and knowledge. Stream systemic reliability Pss is a scalar value, i.e. a number from the continuum between zero and one. The Pss value characterises failure-free operation of the whole system. Its average value in the normative time tn expresses the efficiency of the manufacturing system. The value Pss is a quotient of the number of important relation and the sum of important and supportive relations. The formula for Pss shows the method of optimising the process through the increasing of the number of important relations between the input stream components. The concept has been applied to study the efficiency of operation of a small-scale bakery. Systemic analysis of a bakery allows for important increase in the reliability of baking bread if robotisation has been implemented. The concept of systemic-stream reliability Pss may be applied to analyse the efficiency of any technological process and optimisation of any manufacturing process.

Topological Modeling Research on the Functional Vulnerability of Power Grid under Extreme Weather

The large-scale interconnection of the power grid has brought great benefits to social development, but simultaneously, the frequency of large-scale fault accidents caused by extreme weather is also rocketing. The power grid is regarded as a representative complex network in this paper to analyze its functional vulnerability. First, the actual power grid topology is modeled on the basis of the complex network theory, which is transformed into a directed-weighted topology model after introducing the node voltage together with line reactance. Then, the algorithm of weighted reactance betweenness is proposed by analyzing the characteristic parameters of the power grid topology model. The product of unit reliability and topology model’s characteristic parameters under extreme weather is used as the index to measure the functional vulnerability of the power grid, which considers the extreme weather of freezing and gale and quantifies the functional vulnerability of lines under wind load, ice load, and their synergistic effects. Finally, a simulation using the IEEE-30 node system is implemented. The result shows that the proposed method can effectively measure the short-term vulnerability of power grid units under extreme weather. Meanwhile, the example analysis verifies the different effects of normal and extreme weather on the power grid and identifies the nodes and lines with high vulnerability under extreme weather, which provides theoretical support for preventing and reducing the impact of extreme weather on the power grid.

Vehicle Routing for Dynamic Road Network Based on Travel Time Reliability

Vehicle path selection follows the shortest path principle, while taking the shortest travel time as the optimization goal. In the real road network, affected by signal control, the travel time of the vehicle path has significant uncertainty. The shortest path algorithm with static road indicators as the weights has obvious defects in path selection. In order to solve this problem, according to the theory of distributed wave, the operating state of the vehicle under the influence of the downstream signal control is classified. The travel time of the vehicle on the road segment is classified and predicted, and the travel time prediction value set is further transformed into the travel time reliability. For the vehicle route selection of a dynamic road network, the path travel time reliability determined by the product of the road segment travel time reliability is logarithmically converted, and the Dijkstra algorithm is used to find the most reliable path as the target solution. Then, a simulation model is constructed to verify the validity of the algorithm. The experimental results prove that using the reliability of travel time as the weight of path selection and solving by Dijkstra algorithm can reflect the actual vehicle path selection more accurately. This method is a beneficial improvement to the problem of static path selection.

Statistical reliability of noise hindrance for ensuring protection against leakage of information through technical channels

The statistical reliability of the noise hindrance that used to protect the information against leakage through technical channels is grounded in this paper. It is a component of technical reliability of information security system and it is defined as the probability that the statistical characteristics of the studied noise hindrance will not go beyond the permissible limits. The use of this noise hindrance in security systems will guarantee to act with an effective spectral density, which will provide the necessary probability of errors and other security indicators in channel of leakage. Assessment of the effective spectral density is carried out regarding the decisive scheme of the ideal receiver, which is built on the criterion of Kotelnikov and it includes the following steps: determination function of correlation of noise process, the verification process on stationary and ergodicity, its verification on the normal distribution and the calculation of the sought effective spectral density. Determining the function of correlation of noise process is carried out with so-called “margin” on the error for the worst case from the point of view of security. Verification of the process on the temporal homogeneity and ergodic performed using Slutsky conditions. The resulting statistical reliability of the noise hindrance is the product of the statistical reliability of the estimates at all stages. It is an indicator of the reliability guarantee and component information security system as a whole.

Can a Non-Probabilistic Online Panel Achieve Question Quality Similar to that of the European Social Survey?

Recently, Revilla and Saris (2012) showed, using data from the Netherlands, that the quality of responses (product of reliability and validity) in a probability-based online panel (LISS) can be similar to those from face-to-face surveys (European Social Survey round 4). However, most online panels select their members in a non probability-based way. They usually also send many more surveys per month to their panellists. Both together can generate professional respondents whose quality of answers may be different. Therefore, it makes sense to make a similar comparison for a nonprobability-based online panel (Netquest). Although differences are found, the similarities prevail. Overall, we cannot say that one of the surveys has higher estimates of quality, when defined as the product of reliability and validity, than the other.

Reliability and safety analysis of redundant vehicle management computer system

Redundant techniques are widely adopted in vehicle management computer (VMC) to ensure that VMC has high reliability and safety. At the same time, it makes VMC have special characteristics, e.g., failure correlation, event simultaneity, and failure self-recovery. Accordingly, the reliability and safety analysis to redundant VMC system (RVMCS) becomes more difficult. Aimed at the difficulties in RVMCS reliability modeling, this paper adopts generalized stochastic Petri nets to establish the reliability and safety models of RVMCS. Then this paper analyzes RVMCS operating states and potential threats to flight control system. It is verified by simulation that the reliability of VMC is not the product of hardware reliability and software reliability, and the interactions between hardware and software faults can reduce the real reliability of VMC obviously. Furthermore, the failure undetected states and false alarming states inevitably exist in RVMCS due to the influences of limited fault monitoring coverage and false alarming probability of fault monitoring devices (FMD). RVMCS operating in some failure undetected states will produce fatal threats to the safety of flight control system. RVMCS operating in some false alarming states will reduce utility of RVMCS obviously. The results abstracted in this paper can guide reliable VMC and efficient FMD designs. The methods adopted in this paper can also be used to analyze other intelligent systems’ reliability.

SYSTEM AND METHOD FOR EFFICIENT TRACKING OF MULTIPLE DIALOG STATES WITH INCREMENTAL RECOMBINATION

Disclosed herein are systems, methods, and computer-readable storage media for tracking multiple dialog states. A system practicing the method receives an N-best list of speech recognition candidates, a list of current partitions, and a belief for each of the current partitions. A partition is a group of dialog states. In an outer loop, the system iterates over the N-best list of speech recognition candidates. In an inner loop, the system performs a split, update, and recombination process to generate a fixed number of partitions after each speech recognition candidate in the N-best list. The system recognizes speech based on the N-best list and the fixed number of partitions. The split process can perform all possible splits on all partitions. The update process can compute an estimated new belief. The estimated new belief can be a product of ASR reliability, user likelihood to produce this action, and an original belief.

Impact of the Mode of Data Collection on the Quality of Answers to Survey Questions Depending on Respondent Characteristics

The Internet is used more and more to conduct surveys. However, moving from traditional modes of data collection to the Internet may threaten the comparability of the data if the mode has an impact on the way respondents answer. In previous research, Revilla and Saris (2012) find similar average quality (defined as the product of reliability and validity) for several survey questions when asked in a face-to-face interview and when asked online. But does this mean that the mode of data collection does not have an impact on the quality? Or may it be that for some respondents the quality is higher for Web surveys whereas for others it is lower, such that on an average the quality for the complete sample is similar? Comparing the quality for different groups of respondents in a face-to-face and in a Web survey, no significant impact of the background characteristics, the mode and the interaction between them on the quality is found.

Reliability of asic devices

Abstract The use of application-specific integrated circuits (ASICs) has become widespread; from use in sophisticated telecommunications equipment through to children's toys. However, aspects of design, fabrication and testing may not be as rigorous as for the standard components that they are replacing. ASICs by their nature are usually low volume components and tend to be fabricated using the latest technology. However, the additional substantial costs involved with comprehensive reliability and quality assessment mean that testing is often less exhaustive, resulting in a product of uncertain reliability. Conventional wisdom states that fewer components will mean greater reliability; however if the devices are replaced by one of uncertain reliability, this will not necessarily be the case. This paper presents some considerations that should to be taken into account when contemplating the use of ASICs in place of conventional components. These are highlighted with specific examples seen at Telecom Austra...

An Attempt to Unify Reliability and Confidence Level in Reliability-Based Design.

In reliability-based design and reliability testing, the reliability and confidence level are used together when distribution parameters are unknown. Determination of the design allowable stress in the MIL Handbook is a typical example. This conventional method of using the two-dimensional measure is somewhat complicated, and makes it difficult to compare allowable stress based on different confidence levels. In the present paper, the idea of using the mean reliability as a one-dimensional measure was proposed. This idea was applied to the determination of the design allowable stress Sa for the case when the strength follows a normal distribution N(μ, σ2). The factor k in the expessions of Sa= μ-kσfor the case of unknown μ, and Sa= μ-kσ for the case of unknown μand σ was derived based on this idea, where μand σare estimated values. A method for specifying the design goal of the mean reliability was also proposed. Furthermore, the meaning of the product of reliability and confidence level was clarified.

The hierarchy of consistency: A review and model of longitudinal findings on adult individual differences in intelligence, personality and self-opinion

When viewed in the aggregate, studies of the longitudinal consistency of intelligence, personality traits and self-opinion (self-esteem, life satisfaction etc.) show a hierarchy of consistency. Uncorrected retest coefficients over periods of 6 months to 50 yr are analyzed as the product of period-free reliability ( R) and the true stability of the construct ( s n , where s is the coefficient of annual stability and n the number of years of the retest interval). The annual stabilities of intelligence, personality traits and self-opinions are estimated as 0.99, 0.98 and 0.94, respectively. While intelligence and personality may be regarded as relatively stable characteristics over the length of the adult lifespan, self-opinion has little stability over periods of more than 10 yr. The hierarchy of consistency should be taken into account in causal models of human development. Although self-opinion is not a longitudinally-stable characteristics, it may still be predicted over long periods of time by higher-order constructs such as personality traits and intelligence.

Improved Producibility and Reliability through Process Oriented Design

The electronic industry is faced with the problems of increased material and labor costs, production capacity and adequate skilled labor. These problems can all be solved to a great extent by utilizing a technique called "process oriented design." Some of the by products of this technique result in lower workmanship defects and less scrap loss, which reflects into the ability to produce a product of higher quality and better reliability for a lower cost.

Thin-film integrated electronic reliability

A reliability approach on thin-film integrated electronics is discussed in which the overall (inherent) reliability Po <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</inf> of a circuit is determined as the product of the individual part reliability P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> , design reliability P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</inf> , and fabrication reliability P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</inf> . This article presents data collected on the individual part reliability term for vacuum deposited thin-film resistors and capacitors. Maximum failure rates (at a 60 per cent confidence level) of 0.014 per cent per 1000 hours and 0.057 per cent per 1000 hours are reported for resistors and capacitors based on 8,000,000 element hours of data. The process used in fabricating the thin-film circuits is outlined.