A. K. Barak ¹, S. C. Malik ¹

Affiliations
1 Department of Statistics, M.D. University, Rohtak-124001, Haryana, IN

Abstract

A computer system is analyzed considering the concept of priority to Preventive Maintenance (PM) over hardware repair subject to maximum operation and repair times. Two-identical units of the computer system have been taken up-one is initially operative and other is kept as spare in cold standby. In each unit, hardware (h/w) and software (s/w) work together and may fail independently from normal mode. There is a single server who visits the system immediately when needed to carry out repair activities. PM of the unit is conducted after a Maximum Operation Time (MOT). If repair of the h/w is not possible up to a maximum repair time, it is replaced by a new one with some replacement time. However, only replacement of the s/w is made giving some replacement time with the new one when s/w fails to execute the program properly. Priority to PM of the unit is given over h/w repair. The failure time of the unit follows negative exponential distribution while the distributions of PM, repair and replacements are taken as arbitrary. To carry out the cost-benefit analysis, expressions for several reliability measures are obtained by using semi-Markov and regenerative point technique. The graphical behaviour of some important performance measures of the system has been examined giving particular values to various parameters and costs.

Keywords

Computer System, H/w and S/w Failure, Priority, Maximum Operation And Repair Time, Preventive Maintenance and Cost-benefit Analysis

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D. Pawar ¹, S. C. Malik ², Reetu ²

Affiliations
1 Amity Institute of Telecom Engineering and Management, Amity University, Noida–201303, IN
2 Department of Statistics, Maharshi Dayanand University, Rohtak–124001, IN

Abstract

In this paper reliability measures of a single-unit system operating under two weather conditions – normal and abnormal are evaluated using regenerative point technique. For this purpose, a reliability model is developed in which partial failure unit, fails totally. A single server randomly appears at partial failure of the unit on condition to visit immediately on complete failure of the system. The inspection of the unit at its partial failure is to assess the possibility of on-line repair. If not possible, it is repaired in down state. The repair of the unit at its complete failure is done without inspection. Server remains with the system in abnormal weather. The failure time of the unit and time of change of weather conditions are distributed exponentially; while the distributions of inspection and repair times are taken as arbitrary. Graphs are drawn to depict the behavior of some reliability and economic measures.

Keywords

Weather Conditions, Conditional Random Appearance of the Server, Inspection, On-line Repair, Partially Failure Stage (PFS), Reliability Measures

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Vinay Kumar ¹, S. C. Malik ¹

Affiliations
1 Department of Statistics, M.D. University, Rohtak, Delhi Road, University Secretariat, Rohtak - 124001, Haryana, IN

Abstract

Objectives: India is one of major contributors to global burden of tuberculosis which alone accounted for an estimated one quarter (26%) of all tuberculosis cases worldwide. The estimation of disease burden of tuberculosis is a challenge, considering its varied epidemiology and dynamics of transmission. As true disease burden cannot be estimated with count data therefore, statistical modelling techniques have been employed to analyze the disease burden in terms of prevalence of tuberculosis among males and females. Methods: An attempt has been made to predict gender bias in the prevalence of tuberculosis. The statistical models for both male and female tuberculosis positivity are developed on the information taken from NHFS (2015-16). The gender wise prevalence of tuberculosis has been compared by considering different indicators. In our analysis, the binary logistic regression model has been used by considering some factors to know their impact on prevalence of the tuberculosis. Results: Some of the variables under socioeconomic factors, Demographic Factors, Cultural factors and Health factors have shown decline their impact on prevalence of tuberculosis in males as compared females. However rests of the variables have the impact on the prevalence of tuberculosis without any variation. Conclusion: The study reveals that there are some factors which are responsible for prevalence of tuberculosis in India among male as well as in females and these factors are continuously contributing in increasing the prevalence of tuberculosis. Hence it is suggested that there is a need to redesign the policies to minimize the risk factors generated on the part of the factors having same impact on the prevalence of tuberculosis to avoid gender bias.

Keywords

Body Mass Index, Explanatory Variables and Logistic Regression, Risk Factors, Tuberculosis.

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