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RT&A 2017, # 2(45) Vol.12


 

Dimitrov, Boyan

 

Why We Need Probability Distributions With Periodic Failure Rates In Reliability And Risk

We discuss situations in real life where probability distributions with periodic failure rates should be considered. This discussion leads us to a new class, called Almost-Lack-of-Memory (ALM) probability distributions. We explain the structure of these distributions, and list some of their important properties. One of the main properties is its periodic failure rate. Throughout this article we notice some areas of possible applications of these distributions, and relate applications to the properties of these distributions. However, periodic variability also is observed. This may be another interesting continuation of this study.

 

Keywords: ALM class of probability distributions; Periodic failure rate functions; Non-homogeneous Poisson Process; periodic random environment

 

Farhadzadeh, E.M., Muradaliyev, A.Z., Farzaliyev, Y.Z.,

Rafiyeva, T.K. Abdullayeva, S.A.

 

Reliability of the Estimate of Interrelation of Parameters Efficienty Their Work of Objects of Ees                  

Given is computational method of statistical distribution function of possible realizations of coefficients of linear correlation of Pearson and grade correlation of Spirmen for dependent random quantities. Dependence provided with ranging of random quantities of selections. Random quantities are modeled and have uniform distribution in the range of [0,1]. These distributions allow to evaluate the error of II type and to compare it with the error of I type.  The error of II type established on statistical distribution function of coefficient correlation of independent selections. These distributions are in a basis of criteria for estimate of the importance of coefficients of correlation of technical and economic parameters of objects of electrical power systems.

 

Keywords: Correlation coefficient, selection, ranging, distribution, technical and economic indicator

 

Paramonov, Yuri 

 

Modeling of Fatigue Life  of Unidirectional Fibrous Composite by Daniels' Epsilon-Sequence  Under Random Loading

The modified Daniels' epsilon sequence (DeS) is used for an  analysis of a residual static strength, a  fatigue life, a fatigue strength of an unidirectional fiber composite (UFC) considered as some parallel system  subjected to cycling loading with a random value of a cycle parameter. Some example of the processing of  data set of a carbon-fiber reinforced composite is given.

 

Keywords: Danielsí sequence, strength, fatigue life, composite

 

Rykov, V.

 

Controllable  Queueing Systems: From the Very Beginning up to Nowadays

The present paper represents a review of the Controllable Queueing Systems theory development from the very beginning up to nowadays. The main stages of this theory development are considered. Some new problems are mentioned. The review is devoted to those, who are interested in the creation and the development of the Controllable Queueing Systems theory from its generation up to nowadays, and who want to understand the tendency of its development and the new directions and problems of its study.

 

Keywords:  Controllable queueing systems, Markov decision processes, Optimality principle, monotonicity of optimal policies

 

Gadolina, I., Lisachenko, N.

 

Percentiles Confidence Intervals Building Using Bootstrap-Modeling: Application for High-Tech Production Quality Control

We propose a method for building confidence intervals for percentiles with application to quality control of the random properties of composite polymer materials strength. The basises (i.e. lower confidence limits for percentiles) are analyzed.  The new developed method employs the statistical bootstrap modeling method. For the explanation of bootstrap procedure, the problem of building confidence interval for the mean value for the random values of composite material strength is presented. The result is compared with classical one. Due to bootstrap, it is possible to overcome some problems of classical statistical constraints. There is no need in postulating some type of distribution (normal or Weibull). Some real problems are presented with the comparison of the results by standard procedures and by the new method. It is shown that the agreement is satisfactory.

 

Keywords: percentile, bootstrap-modeling, composite material, strength

 

 Deepak, T.G.

 

A Queueing Network Model for Delay and Throughput Analysis in Multihop Wireless Ad Hoc Networks

In this paper we present a queueing network model for computing average end-to-end delay, and maximum throughput that can be attained in random access multi-hop wireless ad hoc networks with stationary nodes under two popular contention resolution schemes namely, Binary Exponential Back-off (BEB) and Double Increment Double Decrement (DIDD) rules. This model takes into consider some realistic features of the system like (i) the generation of different classes of packets at nodes, and (ii) the dependence of the transmission time and transmission probability on the distance between the transmitter and receiver. Probability distributions and the associated measures of characteristics of the time spent by a packet at arbitrary node are analytically derived by using phase type random variate theory, which in turn are used for the computation of average end-to-end delay and maximum achievable throughput. Theoretical results are numerically illustrated.

 

Keywords: queue, network, phase type distribution, Markov chain

 

Gnedenko, E., Rice, D.

 

The Economics and Management of Nuclear Energy Industry: Supply Chain Reliability and Safety

Nuclear energy safety is a critical issue as the world increasingly turns to nuclear energy to meet our growing needs for power and decreasing dependence on fossil fuels. Major nuclear disasters like Chernobyl (1986) and Fukushima Daiichi (2001) demonstrate the need for improved controls of these systems. The nuclear power supply chain is a critical component of the highly interconnected nuclear energy system. This paper introduces industry best practices and how these relate to the nuclear energy industry safety and reliability.

 

Keywords: Nuclear energy, safety, supply chain, reliability, operations costs

 

Gnedenko, D. 

 

B. V. Gnedenko. Bibliography

The bibliography, which we present below, includes everything that could be found from the written and published B.V. Gnedenko, starting with books and ending with newspaper articles. This includes also published interviews. The bibliography is broken down by years, and for each year everything that was published during this year, including reprints, is presented. The work for each year is arranged in one definite order: books, scientific articles, articles on various aspects of teaching, reviews, articles from general journals, newspaper publications, interviews. If the same article was published during the year in different places, then it is indicated under the same number, listing the output of all publications. Sometimes during the year there are articles with the same name, but different content. They are listed under different numbers, if possible, nearby.

 

Keywords: Gnedenko, bibliography, memory, history

 

 

 

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