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RT&A 2021, # 2(62) Vol.16

 


 

Aditya Tiwary, Swati Tiwary

An Innovative Methodology for Evaluation of Reliability Indices of Electric Traction System

Evaluation of reliability is most important when we have to check the availability of supply in any electric power system. The basic reliability index which is of importance is failure rate, repair time and unavailability of the supply in any electric power system. In this paper evaluation of various basic reliability indices for the electric traction system is done. Electric traction system is very important as it is used for operation of passenger trains and freight trains across a large rail network throughout the world. As the traction system is very important therefore reliability evaluation of its various parameters are essential for proper and uninterrupted working of the whole electric traction system.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-13-21

 



V.V. Singh, P. K. Poonia, Jibril Umar Labaran, Ibrahim Abdullahi

Probabilistic analysis of a multi-state warm standby k-out-of-n: G system in a series configuration using copula linguists

This paper discusses the reliability analysis of repairable complex system comprising of two subsystems in series configuration together with the controllers. The two subsystems, consisting of three undistinguishable units in a parallel arrangement and functioning under 1-out-of-3: G operational policy. Controllers control both the subsystems and can be unstable, and the malfunction result in the controller prevents system operation. The system may have an unforeseeable catastrophic failure due to which the system may not perform its function once the situation arises. The failure rate of the units is constant, and the exponential distribution is assumed to obey. The two forms of repair namely general repair and Goumbel-Hougard copula repair are used to restore the existing failed units of the system. The supplementary variable technique with Laplace transformation is used to evaluate the output of the system. Using Stochastic theory, differential equations are derived to obtain essential features of reliability such as availability of the system, reliability of the system, MTTF, and profit analysis. Graphs were drawn to highlight the behavior of the results. Tables and figures display the findings and suggest that copula repair is a more efficient repair policy for the improved performance of repairable systems. It brings a different aspect to the research world to adopt multi-dimensional repair in the form of the copula. Besides, the findings of the model are useful for system engineers and maintenance managers.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-22-39

 



Gurami Tsitsiashvili, Yuriy Kharchenko

Digitalization of Information Specified on the Grid

Digitalization is the process of implementing digital transmission systems at the level of primary networks, switching and control facilities that ensure the transmission and distribution of information flows in digital form at the level of secondary networks, which makes production more flexible, competitive, and profitable. First point considered here is an introduction of mathematical equivalent to the concept of a pixel, used when replacing the original information with its step-by-step approximation and estimate of its accuracy. Second point is the study of special knots: extreme knots or saddle knots on the grid and construction of level lines around them: ellipses or hyperbolas. This construction is connected with some meteorological problems and is based on the concept of positive definite quadratic form. Third point is an estimation of the average number of Poisson flow points in several cells of a square lattice in different problems of earth sciences. It is solved by introduction of relative error of the estimate.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-40-44

 


 

Intekhab Alam, Mohd Asif Intezar, Aquil Ahmed

Costs of Maintenance Service Policy: a New Approach on Constant Stress Partially Accelerated Life Test for Generalized Inverted Exponential Distribution

In this paper, we describe how to analyze and propose the accelerated life test plans for the development of the excellence and reliability of the product. We focus on estimating the costs of maintenance service policy because it has a very significant position to assist any manufacturing organization for sale and available its equipment and maintenance cost-effective. The constant-stress partially accelerated life test is assumed when the lifetime of test units follows Generalized Inverted Exponential distribution under the progressive censoring scheme. The maximum likelihood estimates, Fisher Information matrix, and the asymptotic variance and covariance matrix are obtained. The confidence intervals of the estimators are also obtained. Furthermore, a simulation study is conducted to check the accuracy of the findings.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-45-57
 


 

Gauthami P., Chacko V. M.

Dus Transformation of Inverse Weibull Distribution: An Upside-Down Failure Rate Model

A new upside-down bathtub shaped failure rate distribution, DUS Inverse Weibull (DUS-IW) distribution is proposed and its properties are studied. The DUS-IW distribution has upside-down bathtub shaped and decreasing failure rate functions. Moments, moment generating function, characteristic function, quantiles, etc. are derived. Estimation of parameters of the distribution is performed via maximum likelihood method. Reliability of single component and multi component stress-strength models are derived. A simulation study is performed for validating the estimates of the model parameters. DUS-IW distribution is applied to two real data sets and found that DUS-IW distribution is a better fit than other well-known distributions.
 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-58-71

 


 

Abdul Alim, Diwakar Shukla

Double Sampling Based Parameter Estimation in Big Data and Application in Control Charts
 

Double sampling technique and control charts are used for predicting about unknown parameters of the big population and developing algorithms for imposing control over growth factor. This sampling procedure has two approaches like sub-sample and independent sample. Aim is to estimate mean file-size by both and to find out which approach is better in big data setup. Comparative mathematical tools used herein are mean squared error, confidence interval, relative confidence interval length measure and control charts of digital file-size for monitoring. Estimation strategies are proposed and confidence intervals are computed over multiple points of time. At each time, it was found that confidence intervals are catching the true values. First kind of approach (as case I) of double sampling found better than the second. A new simulation strategy is proposed who is observed efficient for comparison purpose. Single-valued simulated confidence intervals are obtained using the new simulation strategy and found covering the truth in its range. As an application of outcomes, control charts are developed to monitor the parametric growth over long duration. Upper and Lower control limits are drawn for business managers to keep a watch on digital file-size estimates whether their growth under control? Outcomes may be extended for reliability evaluation under discrete time domain. The content herein is a piece of thought, idea and analysis developed by deriving motivation from past references to handle big data using double sampling. Findings of the study can be used for developing software based monitoring system using process control charts for managers.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-72-114

 


 

Baranov, L.A., Ermolin, Y.A., Shubinsky, I.B.

On a Reliability of Tree-Like Transportation Networks

The degree of reliability of the transportation tree-like networks is proposed to be estimated by the index of operational reliability, which is the relative volume of the product not delivered to the point for some time due to the failures of its elements. A method is proposed for calculating this index using a characteristic feature of the structure of transportation network – a tree-like structure and assumes the time invariance of failure and repair flows of its elements. On such structure, the Y-shaped structure-forming fragment is distinguished, the assessment of the reliability of which (in the accepted understanding) is carried out analytically using the concept of the state space. Each of Y-shaped fragment is virtually replaced by one fictitious element, the destruction parameter of which is calculated from the condition of equality of the volumes of the product undelivered to the network output during such a replacement. The calculation of the operational index is reduced to a step-by-step recurrent procedure using the results obtained in the previous step.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-115-123

 



S. Adilakshmi, Dr. N. Ravi Shankar

A New Ranking in Hexagonal Fuzzy number by Centroid of Centroids and Application in Fuzzy Critical Path

This paper intends to introduce a different ranking approach for obtaining the critical path of the fuzzy project network. In the network, each activity time duration is viewed by the fuzzy hexagonal number. This study proposes an advanced ranking approach by applying the centroid of the Hexagonal fuzzy number. The Hexagon is separated into two right angles and one polygon. By applying the right angle and polygon centroid formula, we can calculate the centroid of each plane and calculate the centroid of the centroid. It also focuses on the arithmetic operations in Hexagonal fuzzy numbers. The developed strategy has been described by a numerical illustration and is correlated with a few of the existing ranking approaches.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-124-135

 



K.M. Sakthivel, K. Dhivakar

Type II Power Topp-Leone Daggum Distribution With Application In Reliability

In this paper, we introduce a new continuous probability distribution named as type II power Topp-Leone Dagum distribution using the type II power Topp-Leone generated family studied by Rashad et al.. We have obtained some reliability measures like reliability function, hazard rate function, reversed hazard rate function, mean waiting time, mean past life time, mean deviation, second failure rate function and mean residual life function. We have derived some statistical properties of the new probability distribution including mean, variance, moments, moment generating function, characteristics function, cumulant generating function, incomplete moments, inverted moments, central moments, conditional moments, probability weighted moments and order statistics. For the probability proposed new probability distribution. we have obtained some income inequality measures like Lorenz curve, Bonferroni index, Zenga index and Generalized entropy. The maximum likelihood estimation method is used to estimate the parameters of the probability distribution. Finally, the proposed generalized model is applied to life time data sets to evaluate the model performance.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-136-156

 


 

Vladimir Rykov

Decomposable Semi-Regenerative Processes: Review of Theory and Applications to Queueing and Reliability Systems

A review of the Smith’s regeneration idea development is proposed. As a generalization of this idea the main definitions and results of decomposable semi-regenerative processes are reminded. Their applications for investigation of various queueing and reliability systems are considered.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-157-190

 



G. Ayyappan, R. Gowthami

A MAP/PH/1 queue with Setup time, Bernoulli vacation, Reneging, Balking, Bernoulli feedback, Breakdown and Repair

A single server classical queueing model with Markovian Arrival Process (MAP), phase-type(PH) distributed service time and rest of the random variables are distributed exponentially is investigated. By making use of matrix analytic method, the resultant QBD process is examined in the stationary state. The practical applicability, objectives and the uniqueness of our model have been provided. The busy period analysis has been done and the distribution function for the waiting time has also been obtained. Some performance measures are enlisted. At last, some graphical and numerical exemplifications are furnished.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-191-221

 



Md. Asraful Haque, Nesar Ahmad

A Software Reliability Growth Model Considering Mutual Fault Dependency

Many software reliability growth models (SRGMs) have been introduced since 1970s. Most of the models consider that the faults are independent and debugging method is perfect. In this paper, we present a new SRGM under the assumption that the faults are mutually dependent i.e. repairing a detected fault may introduce new faults or it may simultaneously correct some future faults without any additional effort. The model is validated on two real datasets that are widely used in many studies to demonstrate its applicability. The comparisons with eight established models in terms of Mean Square Error (MSE), Variance, Predictive Ratio Risk (PRR) and R2 have been presented.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-222-229

 



Brijesh P. Singh, Utpal Dhar Das, Sandeep Singh

A Compounded Probability Model for Decreasing Hazard and its Inferential Properties

Early failures are generally observed due to latent defects within a product caused by faulty components, faulty assembly, transportation damage and installation damage. Also early life (infant mortality) failures tend to exhibit a decreasing failure rate over time. Such type of problems can be modelled either by a complex distribution having more than one parameter or by finite mixture of some distribution. In this article a single parameter continuous compounded distribution is proposed to model such type of problems. Some important properties of the proposed distribution such as distribution function, survival function, hazard function and cumulative hazard function, entropies, stochastic ordering are derived. The maximum likelihood estimate of the parameter is obtained which is not in closed form, thus iteration procedure is used to obtain the estimate of parameter. The moments of the proposed distribution does not exist. Some real data sets are used to see the performance of proposed distribution with comparison of some other competent distributions of decreasing hazard using Likelihood, AIC, AICc, BIC and KS statistics.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-230-246

 


 

Pradeep Chaudhary, Lavi Tyagi

A Two Non-Identical Unit Parallel System Subject to Two Types of Failure and Correlated Life Times

The paper deals with the reliability and cost-benefit analysis of a two non-identical unit system with two types of failure. The units are named as unit-1 and unit-2 and they are arranged in a parallel configuration. Unit-1 can fail due to hardware or due to human error failure whereas unit-2 fails due to normal cause. A single repairman is considered with the system for all types of failure in the units and unit-1 gets priority in repair over the unit-2. The repair time distributions of unit-1 are taken as general with different c.d.fs and the repair time distribution of unit-2 is taken as exponential. Failure time distribution of unit-1 due to human error is taken exponential. Whereas the random variable denoting the failure time of unit-1 due to hardware failure and random variable denoting the failure time of unit-2 are assumed to be correlated random variables having their joint distribution as bivariate exponential (B.V.E.).

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-247-258

 



Ibrahim Yusuf, Abdullahi Sanusi

Optimal System for Five Units Serial Systems under Partial and Complete Failure

The present paper studies and compared some reliability characteristics of series-parallel systems containing five units each under partial and complete failure. Four different system configurations are considered in this paper. It is assumed that both the failure and repair rates of each system configuration follow exponential distribution. The steady-state availability, busy period of repairman due to partial and complete failure, profit function, mean time to failure (MTTF) have been derived, examined and compared. The system configurations are compared analytically in terms of their availability and mean time to failure (MTTF). Cost-benefit measure has been evaluated for all the system configurations. The computed results are presented in tables and figures. From the analysis, system configuration II is observed to be the optimal configuration.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-259-278

 



Noura Obeid, Seifedine Kadry

Product Of n Independent Maxwell Random Variables

We derive the exact probability density functions (pdf) of a product of independent Maxwell distributed random variables. The distribution functions are derived by using an inverse Mellin transform technique from statistics, and are given in terms of a special function of mathematical physics, the Meijer G-function.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-279-288

 


 

Haneefa Kausar, Ahmad Yusuf Adhami, Ahmadur Rahman

Quadratic Fractional Bi-level Fuzzy Probabilistic Programming Problem When bi Follows Exponential Distribution

Some of the actual life decisions are made in decentralized manner under uncertainty. This paper formulates a quadratic fractional bi-level (QFBL) programming problem with probabilistic constraints in both first (leader) and second level (follower) having two parameter exponential random variables with known probability distributions and fuzziness is considered as triangular and trapezoidal fuzzy number. These fuzzy numbers of the membership functions related with the proportional probability density function has been used to introduce a defuzzification approach for finding the crisp values of fuzzy numbers. In the proposed model the problem is first converted into an equivalent deterministic quadratic fractional fuzzy bi level programming model by applying chance constrained programming technique. Secondly, in the suggested model, each objective function of the bi-level quadratic fractional programming problem has its own non-linear membership function. The fuzzy goal programming (FGP) approach is used to find a compromise solution for the BLQFP problem. Finally, to demonstrate the applicability and performance of the proposed approach an illustrative numerical example is given.

 

 

DOIhttps://doi.org/10.24412/1932-2321-2021-262-289-300

 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

Safety Research :

 

 

Safety, Risk, Reliability and Quality:

 

 

Statistic, Probability and Uncertainty :