Because of its logically centralized design, Software-defined Networking (SDN) is vulnerable to a variety of adversarial attacks. These attacks have the possibility of degrading the coordinated network's efficiency or, in the most severe scenario, bring it down. As a result, SDN efficiency must be assessed and estimated to ascertain its performance through reliability, mean time to failure (MTTF), cost, MTTF sensitivity and availability.In this paper, a system with four subsystems, (subsystem-1, subsystem-2, subsystem-3 and subsystem-4) is studied. All the four subsystems are connected in a series configuration. Subsystem- 1 has only one unit, subsystem-2 has three units connected in parallel working under 1-out-of-3: G; policy, subsystem-3 has two units connected in series, and subsystem-4 has two units connected in parallel working under 1-out-of-2: G; policy. The system is assumed to work in good operating conditions with different failure rates and repair rates. Laplace transforms and Supplementary variable techniques were used to study the system. Availability, reliability, mean time to failure (MTTF), sensitivity, and cost analysis has been evaluated for particular values of the failure and repair rates. Tables and figures were used to demonstrate the evaluated results.

The purpose of this research is to propose three reliability models (configurations) with standby units and to study the optimum configuration between configurations analytically and numerically. The chapter considered the need for 60 MW generators in three different configurations. Configuration 1 has four 15 MW primary units, two 15 MW cold standby units and one 30 MW cold standby unit; Configuration 2 has three 20 MW primary units, three 20 cold standby units; Configuration 3 has two 30 MW primary units and three 30 MW cold standby units. Some reliability features of series–parallel systems under minor and complete failure were studied and contrasted by the current. Failure and repair time of all units is assumed to be exponentially distributed. Explanatory expressions for system characteristics such as system availability, mean time to failure (MTTF), profit function and cost benefits for all configurations have been obtained and validated by performing numerical experiments. Analysis of the effect of different system parameters on the function of profit and availability has been carried out. Analytical comparisons presented in terms of availability, mean time to failure, profit function and cost benefits have shown that configuration 3 is the optimal configuration. This is supported by numerical examples in contrast to some studies where the optimal configuration of the system is not uniform as it depends on some system parameters. Graphs and sensitivity analysis presented reveal the analytical results and accomplish that Configuration 3 is the optimal in terms of design, reliability physiognomies such as availability of the system, mean time to failure, profit and cost benefit. The study is beneficial to engineers, system designers, reliability personnel, maintenance managers, etc.

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PurposeThe purpose of this paper is to model and to improve the stability and long-lasting operation of the small home solar system configuration regarding the reliability, availability, sensitivity, cost analysis and mean time to failure (MTTF).Design/methodology/approachA model of a small home solar system is designed in this write up. It is designed in a series–parallel configuration, such that four panels are arranged in parallel, working under 1-out-of-4: G; policy and two batteries configured in parallel also, working under 1-out-of-2: G; policy. The panels are connected to a charge controller, then to the batteries and lastly to an inverter, all connected together in series configuration. Different types of system reliability such as reliability, sensitivity, availability, MTTF and cost analysis for particular values of the failure and repair rates have been evaluated by using a supplementary variable and Laplace transforms and demonstrated the computed results on tables and graphs. The main objective here is to improve the stability and long-lasting operation of the small solar system configuration regarding the reliability, availability, sensitivity, cost analysis and MTTF.FindingsThe future behavior of the small solar system and similar systems can be easily predicted at any given time for any parametric values, it is also better to provide repair than replacements in the system for better availability and reliability, it signifies that γp, γb, γc and γi are responsible for the better performance of the system, the variation of sensitivity together with the parametric values variations and lastly deduced that the profit will decrease whenever service cost increase.Originality/valueThis paper provides a model of small home solar system and its reliability analysis.