Reliability Theory

... Suprasad V. Amari, Member, IEEE ... Notation label of component , [failure, repair] rate of component system-failure frequency “mean number of system-failures” per time-unit , Boolean variable indicating that component is [working, failed]; is the complement of , steady state ...

We present a foundational theory of software system re-liability based on components. The theory describes how component developers can design and test their components to produce measurements that are later used by system de-signers to calculate composite system reliability — ...

The main objective of this study is to run a complete structural reliability analysis of an existing villa, located in Lebanon. The structural components, such as slabs, beams, columns, and footings, are first analyzed independently, and the reliability index for each failure mode, is being evaluated at the component level. The structural failure modes are grouped into two categories: the

In this research, it was aimed to develop an instrument for determining problematic
internet usage of university students. Factorial structure of the data collected from
1658 university students revealed three factors. Of these, the first factor is called negative
consequences of the internet and accounted for 25.36% of the variance, the second
factor is called social benefit / social comfort and accounted for 14.62% of the variance,
and the third factor is called excessive usage and explained 8.98 % of the variance.
All three factors consisting of 33 items accounted for the 48.96% of the total
variance. It was found that the scale was able to discriminate problematic internet use
with respect to the time spent on the internet and individuals’ perception of themselves
as the internet addicts. The correlation between the scale and the Davis’s Online
Cognitive Scale-Turkish adaptation (Keser Özcan ve Buzlu, 2005) was found as
0.61. Internal consistency coefficient of the scale (α) was found to be 0.94. Item total
correlations ranged between 0.31 and 0.70 (p<.001). Test-re-test reliability coefficient
was found to be 0.81 and split half reliability coefficient was found to be 0.83. Thus,
the scale called as “the Problematic Internet Usage Scale” was developed.

Mathematical education is essential for the study of psychology, and is especially important for individuals who will engage themselves in research work in this field of social sciences. The variance and covariance are statistical concepts which are important primarily in the analysis of variance, regression analysis, calculating reliability coefficients, as well as determining the extent of variation in the raw scores of the tasks and the overall test. Psychology students often have difficulties in understanding these concepts, which can be improved by providing practical examples in the form of carefully selected problems for exercise and for testing their knowledge. In this paper, it has also been given a short discussion about statistical reasoning.

This paper develops the asymptotic sampling distribution of the inverse of the coefficient of variation (InvCV). This distribution is used for making statistical inference about the population CV (coefficient of variation) or InvCV without making an assumption about the population distribution. It applies to making inferences (point and interval estimation, and hypothesis-testing) about the shape parameter of some popular lifetime distributions like the Gamma, Weibull, and log-normal, when the scale parameter is unknown. The test procedure is used to test exponentiality against a Gamma or a Weibull alternative. The results are compared with those in the literature

In this article results of researches of strategies of maintenances of fault-tolerant informative systems are described. A design process is carried out on the basis of original approach. This approach is realized on application of structurally - automatics models for construction of Markov models.

Improvement factors in hazard rate and age for a sequential preventative maintenance (PM) policy are introduced. Two imperfect PM models are analyzed: (1) PM reduces the hazard rate while it increases with the number of PMs, and (2) PM reduces the age. The PM is done at intervals xk (k=1,2, . . . , N) and is imperfect. The optimal

A National Aeronautics and Space Administration (NASA) supported Reliability, Maintainability, and Availability (RMA) analysis team developed a RMA analysis me thodology that uses cut set and importance measure analyses to compare model proposed avionics computing architectures. In this paper we will present an effective and efficient application of the RMA analysis methodology for importance measures that includes Reliability Block Diagram (RBD) Analysis, Comparison modeling, Cut Set Analysis, and Importance Measure Analysis. In addition, we will also demonstrate that integrating RMA early in the system design process is a key and fundamental decision metric that supports design selection. The RMA analysis methodology presented in this paper and applied to the avionics architectures enhances the usual way of predicting the need for redundancy based on failure rat es or subject matter expert opinion. Typically, RBDs and minimal cut sets along with the Fussell-Vesely (FV) method is used to calculate importance measures are calculated for each functional element in the architecture [1]. This paper presents an application of the FV importance measures and presents it as a methodology for using importance measures in success space to compare architectures. These importance measures are used to identify which functional element is most likely to cause a system failure, thus, quickly identifying the path to increase the overall system reliability by either procuring more reliable functional elements or adding redundancy [2]. This methodology that used RBD analysis, cut set analysis, and the FV importance measures allowed the avionics design team to better understand and compare the vulnerabilities in each scenario of the architectures. It also enabled the design team to address the deficiencies in the design architectures more efficiently, while balancing the need to design for optimum weight and space allocations.

The reliability index ß is a parameter used to estimate the safety of a structure or an element during the design stage or service. This parameter defined in other codes in the world (European Committee for Standardisation (Eurocode), EN 1990:2002; American Association of State Highway and Transportation Officials (AASHTO), 2012), is not specified in the Colombian Code of Bridges Seismic Design (CCDSP-95) (1995). In this paper, it will be presented a study on the estimation of the reliability index ß of the interior and exterior girders of a beam and slab bridge with reinforced concrete, 30 m in length, simply supported and designed according to the CCDSP-95. In the evaluation of the resistant moments, there were considered properties of materials using a normal distribution, and moreover, a Monte Carlo simulation was used to estimate load effect of moment at mid-span of the live load.

In this paper the improvement of method of automated building of state space models of complex technical systems for critical application was proposed. On the basis of the developed model with the split state of critical failure the reliability and safety indexes of studied system can be obtained. Developed approach allows to estimate of reliability and safety indexes, that makes the impact of maintenance strategies on safety and reliability, impact of the fault tolerance on safety to be considered. This will increase the accuracy (certainty) of efficiency indexes estimation of complex technical systems for critical application.

The aim of the current study was to develop a short form of Coping Styles Scale based on COPE
Inventory. A total of 275 undergraduate students (114 female, and 74 male) were administered in
the first study. In order to test factors structure of Coping Styles Scale Brief Form, principal components
factor analysis and direct oblique rotation was used. Factor analysis Results indicated
that Coping Styles Scale Brief Form had 14 factors with two items. All factors explained 80.37% of
the variance in the scale. In order to test concurrent validity of CSS-BF, the relationship between
coping styles, social desirability, self-esteem, life satisfaction and A type personality were examined.
Cronbach’s alfa coefficient of subscales ranged from 0.39 (Restraint Coping) to 0.92 (Humor)
and test re-tests (two weeks interval) coefficients were ranged from .44 (Restraint Coping) to .90
(Religion).

Since the late 90's IP telephony, commonly referred to as Voice over IP (VoIP), has been presented as a revolution on communications enabling the possibility to converge historically separated voice and data networks, reducing costs, and integrating voice, data and video on applications. This paper presents a study over the standard VoIP protocols H.323, session initiation protocol (SIP), media gateway control protocol (MGCP), and H.248/Megaco. Given the fact that H.323 and SIP are more widespread than the others, we focus our study on them. For each of these protocols we describe and discuss its main capabilities, architecture, stack protocol, and characteristics. We also briefly point their technical limitations. Furthermore, we present the advanced multimedia system (AMS) project, a new system that aims to operate on Next Generation Networks (NGN) taking the advantage of its features, and it is viewed as the successor to H.323 and SIP.

The commenter maintains that an expression in the above-mentioned paper (ibid., vol.R-31, p.194-7, June 1982) on which the results are based is wrong, and therefore the results are wrong. The author rebuts the commenter&amp;amp;amp;#39;s argument point by point

ABSTRACT A generalized notion of source divisibility or in other words successive refinement of information with an additional requirement of exponential decrease of error probability is considered. A necessary and sufficient condition for the possibility of such successive refinement is established