Reliability and Maintainability Assessment of Industrial Systems

The paper proposes a dynamic availability analysis approach for the flexible manufacturing system (FMS) under a stochastic environment that machines’ failure and starvation or blockage of production process occur randomly. Accurately knowing the availability of the FMS, which is changing dynamically overtime in a stochastic circumstance could benefit a lot for the improvement or re-design of the system. A two-step stochastic model proposed in current paper that integrates the intermediate buffers into associated workstations equivalently in terms of the relationships between upstream and downstream production rates. Calculation procedures of relevant dynamic availability are established by using the \(Lz\)-transform method, which conquer the states-explosion problem which is common in FMS performance analysis. Meanwhile, the impacts of intermediate buffers on the FMS dynamic availability also revealed, which assist to determine the appropriate volumes of the buffers to satisfy the various FMS production demands. A numerical example is presented for illustrating the effectiveness and rationality of the approach.

Reliability is the probability that a system will perform its intended function satisfactorily during its lifetime under specified environmental and operating conditions. Risk can be measured by assessing the probability of an undesired event (e.g., a system failure) and the magnitude of its consequences. Therefore, risk and reliability are complementary variables. Licensing of nuclear facilities requires safety and risk assessment. Probability risk assessment implies carrying out a quantitative assessment of the reliability of items important to safety (IISs). In addition, reliability assessments are required during all lifetime phases for optimizing plant performance, maintainability and safety. Thus, the outcomes of reliability and risk assessments are interchangeable and complementary. This chapter proposes a framework for integrating reliability and risk assessments of IISs of nuclear facilities using tools of reliability engineering, as Markov models, fault tree analysis, event tree analysis, reliability block diagrams and life data analysis. Based on frequency-dose limits to the public, risk acceptance criteria are also suggested in the scope of the framework. A case study demonstrating the advantages of using the integrated approach applied to a preliminary plant design phase of a nuclear fuel fabrication, to meet risk acceptance criteria and licensing requirements, is presented.

Human decision-making is becoming more complex due to increasing amount of information t that needs to be analyzed in today’s modern systems. Decision-making in business corporations is not an exception. Such complexity raises a question about reliability or broader efficiency and effectiveness of corporate decision-making.

This chapter proposes some kinds of checkpoint systems with general structures, tasks and schemes. We have already considered redundancy techniques which are duplex and majority systems, and have applied them to two checkpoint models in which their interval times are constant and random. Giving overheads for checkpoints, we have obtained the mean execution times until the process succeeds, and have derived optimal checkpoint times to minimize them. In this chapter, we first introduce the standard checkpoint model, and propose general checkpoint models which include parallel, series and bridge systems. Furthermore, we consider tandem and bulk tasks, and apply them to two schemes and compare optimal policies theoretically and numerically. Finally, as examples of the above models, we give four models, obtain their mean execution times analytically and discuss which scheme is better numerically.

Network reliability has been applied to many real-world applications. The popular areas are traffic planning, computer network planning, power transmission planning, etc. However, in the social applications, there are still very limited cases reported. This chapter is planned to introduce the new attempt of applying network reliability in the assessment of business activities. Such attempt is a step toward precision management in business administration. Based on the capability of conducting precision management, a great deal of improvements in business practices can be taken place. Precision performance evaluation for individuals or groups are presented, and a case study is illustrated to show the approach proposed in this chapter.

One of the goals in manufacturing industry is to follow manufacturing standards which ensure that the manufactured products meet expectations of consumers. An Acceptance sampling plan is a tool to ensure that quality of products meet the minimum expected standards. In this chapter, an attempt is made to derive lot acceptance single and double sampling plans based on type ii censored data. The units in the lot have multiple quality characteristics and are processed through multi-stage process. We assume that the quality characteristics of units follow the exponential distribution. The acceptance criterion for the given lot is derived based on mean-life of units in the sample at every stage. Further, two non-linear optimization problems, which minimize the expected total testing cost at the acceptable quality level, are solved. In addition, sensitivity analysis studies are also conducted to assess the behavior of total testing costs with respect to change in producer’s and consumer’s risks and sample sizes. Several numerical examples and two case studies are presented to illustrate our resulting sampling plans.

The success and sustainability of the business industrial system is largely determined by the degree of effectiveness of the production system as its basic integral part. The reliability of the technical system, i.e., the probability of performing the projected goal function in the observed time period, along with the readiness and functional convenience is a basic indicator of the effectiveness of the production system. Maintenance, as an integral part of the production system, has the function of providing the projected level of optimal reliability by implementing activities aimed at ensuring the required level of technical readiness of parts of the technical system. One of the ways to ensure the optimal level of reliability of the technical system is the application of maintenance concepts according to the condition that allows monitoring and control of technical parameters of the state of the elements of technical systems within the production processes. The basis of the application of the condition based maintenance is the introduction of procedures for monitoring and control of condition parameters using technical diagnostic methods. Knowing the current state of the parameters that determine the degree of success of the projected function of the goal of the technical system gives the possibility of timely response to the occurrence of malfunctions and avoid the entry of the system into failure. The paper presents a systematic provision of regular monitoring and control of condition parameters of parts of the technical system of paper machines, specifically vibration levels on high voltage motors, within the industrial system for production of toilet paper using technical diagnostic methods using portable vibration control devices. By timely response to the observed occurrence of increased vibration levels at a specific critical position with the application of technical diagnostic methods and complex maintenance intervention activities, it is possible to avoid unwanted failure, long-term unplanned production downtime and very high maintenance costs. Along with the description of the specific event and preventive action of the maintenance service, the possibility of connecting the observed working position with other critical positions provided with systems for continuous monitoring of operating parameters, specifically the vibration levels of bearings, is indicated. By constantly striving and finding ways to raise the overall level of reliability to a higher level, maintaining the production system plays a major role in providing conditions for continuous production, achieving planned results and profits and sustainability of production and business industrial system in the increasingly demanding world market.

In this paper, a Shuffle Exchange Network with an additional stage (SEN+) is inspected, the probabilities of whose components aren’t known with accuracy. To overcome this difficulty we determined its reliability by using the method of Interval-valued universal generating function (IUGF) and thus the transient state probabilities are obtained in intervals. The reliability has been analyzed in terms of three parameters: Terminal, Broadcast, and Network reliability. Also within the observed network if any of the Switching Element (SE)comes up short and the system quits working then we will replace that SE by a fixed replacement rate to continue the operation of the network. A numerical example is also provided to offer a practical clarification of the proposed technique.

Researchers have widely focused on catering software quality attributes viz. reliability and maintainability. However, the reliance on software and software-based products have redirected the focus of researchers/ engineers towards security. The vulnerability in software can be due to design flaws, implementation errors, configuration errors, etc., making it prone to attacks and can be used for malicious activities. Timely detection and fixation of these loopholes can enhance the development of safe and secure software thereby minimizing the efforts and resources required to fix them afterwards. With the aim of modeling the discovery process of vulnerability, in this chapter time delay-based formulation for vulnerability injection and discovery has been proposed which has been modeled by considering the infinite server queuing theory. For the empirical validation two vulnerability discovery data has been used. Further VIKOR, a well-known Multi Criteria Decision Making (MCDM) technique has been used to rank the different proposed models.

The objective of this chapter is to calculate the performance of a complex system of an energy plant. In this model, deals with the universal generating function technique (UGF) for analyzing the performance of the complex fixable condensate system of an energy plant, the process of analyzing the reliability has been used for exaggerate the capability of the complex system by reducing the failure rate. The illustrated system is divided into six subsystems those are arranged into series parallel combination and by using the z transformation with UGF technique we find the reliability, signature, tail signature, expected time and expected cost and these resulting outcomes help to get the highly beneficial probabilistic approach that analyzed the signature and the reliability of the system in effective manner.

As we all know synergy files are the channel for aspiring engineers and technologists that are striving for a better and more sustainable world. During summers when the temperature can soar to mid 40 °C in many places around the world, air conditioning becomes more than just a luxury however it is costly to cool spaces particularly in areas with a high level of humidity. One of the advantages of cooling instead of heating is that cooling is required more when there is more heat energy around to tap into or in other words there is more energy available. To be more specific we have more solar energy available to us. Here we are interested in the technology that uses heat from the sun to provide energy directly in the thermodynamic circle of an air-conditioner. This research work is dedicated to evaluate the reliability measures of solar air-conditioners which include availability, mean time to failure (MTTF), and sensitivity analysis with their graphical representation by using the Markov process. Along with reliability assessment, Particle Swarm Optimization (PSO) technique is applied with the objective to find the minimum cost of the system while taking maximum reliability as a constraint.

The increasing data infringement is pressuring software organizations to create and maintain secure software. Although, not all assaults can be anticipated or prevented, many can be avoided by eliminating vulnerabilities in software. Security teams must discover a mechanism to understand the interdependence of vulnerabilities after their discovery to identify which security vulnerability pose the greatest risk and demand immediate attention. The limited revenue and the time taken by the software testers put additional pressure to select those with high severity and are being a cause for other severe flaws. Addressing such defects is the main step towards understanding the cause-effect relationship among the vulnerabilities. The present objective is to propose a framework for assessing these interrelationships of various software vulnerabilities by utilizing Fuzzy Decision-making Trial and Evaluation Laboratory (F-DEMATEL). The fuzzy theory assists in the decision mapping, whereas the DEMATEL technique is utilized to illustrate the contextual link between the kinds of vulnerability. The data is validated for software testing company placed in northern India.

Reliability analysis of various components of all-digital protection systems (ADPS) is one of the key parts of the system reliability quantification process. This paper focuses on the reliability indices and signature evaluation of the ADPS. Here, first measure is to find the reliability of the ADPS using UGF having both independent identically and non-identically distributed components. Second measure is to evaluate the signature with the help of Owen’s method using different algorithms where all the system components are coherent. Lastly, we have calculated the mean time to failure with the help of minimal signature. This paper associates with the reliability block diagram (RBD) as well as the system reliability and signature of the considered systems.

The aim of this article is to assess the reliability of an 8 × 8 shuffle exchange network with one stage less (SEN-). The reliability of the 8 × 8 SEN- has been assessed using three criteria: terminal, broadcast, and network reliability. The current paper offers an effective algorithm for calculating the reliability of an 8 × 8 SEN- using the universal generating function (UGF) method. With the help of UGF, the reliability is estimated for both, the same and distinct switching element probabilities. This article also investigates the impact of removing one stage from the usual 8 × 8 shuffle exchange network (SEN).