[Remediation Accessed :N] its supportability. structure, complexity.- Each factor (or group of factors) should be assigned a weighting to indicate its importance to the overall maintainability of the system. Petar Kochovski, Vlado Stankovski, in Security and Resilience in Intelligent Data-Centric Systems and Communication Networks, 2018. Operator error is the second-most common cause of downtimeafter hardware error. This paper presents different maintainability models from various standards and quality models define its sub-characteristics and then perform analytical comparison of these sub-characteristics. This is the earliest time when sufficient data is available to perform a meaningful quantitative evaluation of design characteristics in terms of performance and maintenance. Intrinsic factors contributing to maintainability are: [1] Modularity: Packaging of components such that they can be repaired via remove and replace action vs. on-board repair. Table 14.12. Once a system fault is detected, it is desirable to be able to apply the necessary improvements as soon as possible, without having to shut down the system. When it comes to Reliability and Maintainability (R&M), the public and private sectors’ objectives appear to be aligned. Different SILs correspond to different RAMS management methods, design and analysis methods, and verification methods to be employed in the design. 3. The positioning of maintenance displays, check points, gauges, meters and the position of one assembly with respect to others. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780750635530500090, URL: https://www.sciencedirect.com/science/article/pii/B9780884152576500028, URL: https://www.sciencedirect.com/science/article/pii/B9780884152576500089, URL: https://www.sciencedirect.com/science/article/pii/B9780128126684000034, URL: https://www.sciencedirect.com/science/article/pii/B9780124199729000036, URL: https://www.sciencedirect.com/science/article/pii/B978012811373800001X, URL: https://www.sciencedirect.com/science/article/pii/B9780884152576500016, URL: https://www.sciencedirect.com/science/article/pii/B978012805427700004X, URL: https://www.sciencedirect.com/science/article/pii/B978088415257650003X, URL: https://www.sciencedirect.com/science/article/pii/B978032339617200014X, Product Development (Second Edition), 2014, G.W.A. The simulation creates typical life cycle scenarios for proposed systems, with Monte Carlo simulation methodology. It is an intrinsic property specified by design. This mode places more importance on operational safety of the track components than economical efficiency. Using the container virtualization in data-centric systems offers us high level maintainability due to the nature of containerization technologies. Maintainability is an important factor in the total cost of equipment. The entire unit was modeled through RBDs, considering the redundancies and the possibilities for bypass in each equipment or system configuration. Maintainability is the ability of the system to undergo modifications with a degree of ease. 15 turnouts in the main line are studied with LCC technology, as shown in Figure 14.50. Every software maintainability model has some sub-characteristics which impact on maintainability directly or indirectly. Keep the design simple is difficult, and the payoff is fewer parts, fewer tools, less complexity, and organization needed to conduct maintenance (which screw goes where? Suppose that Tm is the repair time with repair density function m(t). High reliability and maintainability may relate to high purchase cost, but reduced maintenance cost from a relatively lower failure rate of the equipment in use. They are an integral part of RAMS technical requirements. Reliability, maintainability, and availability (RAM) are three system attributes that are of great interest to systems engineers, logisticians, and users. Reliability was first practiced in the early start-up days for the National Aeronautics and Space Administration (NASA) when Robert Lusser, working with Dr. Wernher von Braun's rocketry program, developed what is known as \"Lusser's Law\" . If the efficiency target is not achieved, it becomes necessary to improve the operational capabilities of critical equipment: Through installing the redundancies in most critical equipment; Through enhancing the reliability and maintainability of equipment used, without the installation of new redundancies; Through maintenance policy that allows keeping the desired availability level. This feature implies the reliability and maintainability of a system. Elements of investment cost related to maintainability, He Ren, ... Yong Chen, in Reliability Based Aircraft Maintenance Optimization and Applications, 2017. Table 14.14 shows a list of common RAMS work contents for turnout, which may be seen as a reference for engineering applications. Each factor will have a maximum score of 10. 3. EVR-UIC60-760-1:15: No. LCC is greatly affected by RAMS. Translator. Here is a list of human factors related, design for maintainability considerations: Consider maintenance from ‘cradle to grave’. An examination of the major interdependent subareas of maintainability and of their relation to human-factor problems. These factors play a crucial role in the maintainability assessments. and Jisc. The factors which affect the frequency with which Ways to improve equipment maintainability. Today software quality is a major point of concern and it is important to be able to assess the maintainability of a software system. Dummer MBE, CEng, FIEE, FIEEE, ... R.C. Because equipment downtime consists of many components and subcomponents, as shown in Figure 1-1 [19], there are numerous engineering and analytical efforts required to reduce downtime. Rather, low reliability and maintainability may relate to low purchase cost but high maintenance cost of the equipment in use. One way to define the difference between reliability and maintainability is that while reliability is the probability that a failure will not occur in a particular time, maintainability is the probability that required maintenance will be successfully completed in a given time period. Designing for Maintainability: Human Factors Considerations. SIL defines the requirements for the safety level of safety-related systems, classified into four levels (SIL4 is the highest requirement). Define supportability and factors that contribute to supportability in systems.] The environment in which maintenance or repairs will be carried out. Translate texts with the world's best machine translation technology, developed by the creators of Linguee. Resolution: Help your operators by ensuring the system is informative and not only signals failure mode but has inbuilt diagnostics for fault finding. In 2008, the code was adopted by China, renumbered as GB/T21562-2008, and renamed “Railway Applications: The Specification and Demonstration of Reliability, Availability, Maintainability and Safety (RAMS).” The application of RAMS is being improved gradually in the design, manufacturing, operation, and maintenance of high-speed turnout products for Chinese HSRs [182]. We use cookies to help provide and enhance our service and tailor content and ads. The feature is based on reliability, availability, and maintainability. Next, the evaluated model was loaded with failure and repair data. B.S. - A list of maintainability factors to be included in the assessment should be devised e.g. The quantitative requirements of RAMS of the turnouts are represented by RAMS parameters and relevant requirements thereof. Design to use common fixtures, fittings (to minimise tooling) and standard parts. Operational reliability defines the performance level of intrinsic reliability of a product in actual use. In the past, planned preventive maintenance, an empirical maintenance mode instead of relying on scientific analysis of reliability and risks, was used in maintaining Chinese railway track structures. Figure 8-1 shows various ways of increasing maintainability [2]. maintainability. Principal factors affecting maintainability. LCC theory has been rooted in China for over 30 years. Collectively, they affect both the utility and the life-cycle costs of a product or system. 15 turnout, UIC60 rails, swing nose crossing, radius of transition lead curve=760 m. The analysis shows that the EV-BV50-600-1:15 turnout has a lower purchase cost than EV-UIC60-760-1:15 (lower by 8%), but it has relatively higher maintenance cost and a shorter life; therefore, its annuity cost is higher by 11% than the latter. 1.2.3 Maintainability Maintainability is the ability of an item to be retained in, or restored to, a specified condition when maintenance is performed by personnel having specified skill levels, using prescribed procedures and resources, at each prescribed level of maintenance and repair. The user may supervise and manage the supplier by specifying compulsory RAMS work content in the procurement agreement for turnouts, so as to ensure the implementation of relevant quantitative and qualitative requirements for RAMS during the process of R&D and production of the products. This could be caused by a number of factors. Request. Required administrative activities and unnecessarily wasted time are both included in administrative time. It is a blend of several metrics, including Halstead’s Volume (HV), McCabe’s cylcomatic complexity (CC), lines of code(LOC), and percentage of comments (COM). Specifically: Figure 14.50. With proper implementation of the proposed architectural approaches for data management, described previously, the developers could achieve high maintainability. Requirements for RAMS work contents are to enable products to meet relevant quantitative and qualitative requirements for RAMS. However, they are particularly pertinent in programs where risks are high or unknown, and failing to achieve the maintainability requirements, highly undesirable. The maintainability of the software system is becoming a very important characteristic due to growth in demand of quality software system. Maintainability prediction is the estimation of maintenance workload (preventive and corrective) associated with the proposed design. Logistic time is that portion of equipment downtime during which repair work is delayed because a replacement part of other component of the equipment is not immediately available. The primary purpose of maintainability measures is to influence design and subsequently produce a more cost-effective and maintainable end product. To obtain satisfactory maintainability the following factors must be considered: (a) The equipment or machine could fail at some time or other. These measures make possible the quantitative assessment of product maintainability. Initially, this theory was mainly used in formulating assessment and inspection policies around equipment status. The RAMS/LCC assessment model is to assess the equipment systems by efficiency and LCC. In the thesis, the annuity costs of three types of No. This paper describes the several types of vital factors that affect the maintainability of software systems as proposed by different researchers in different software maintainability models. Examines the factors that affect the maintainability of a software. Life cycle cost (LCC) is the total cost of a product during its effective use. Ping Wang, in Design of High-Speed Railway Turnouts, 2015. Previous Chapter Next Chapter. Winton MBE, BSc(Eng), ACGI, CEng, FIEE, in, An Elementary Guide To Reliability (Fifth Edition), Aircraft Reliability and Maintainability Analysis and Design, Reliability Based Aircraft Maintenance Optimization and Applications, Comprehensive Reliability Design of Aircraft Hydraulic System, Dependability of Container-Based Data-Centric Systems, Security and Resilience in Intelligent Data-Centric Systems and Communication Networks, Reliability, Availability, and Maintainability (RAM Analysis), Gas and Oil Reliability Engineering (Second Edition), RAM analysis was evaluated using BlockSim and MAROS (, Maintainability Measures, Functions, and Models. CORE is a not-for-profit service delivered by The maintainability effort produces and uses a significant amount of information and data. 1. Table 14.11. Maintainability is a design characteristic that affects accuracy, ease, and time requirements of maintenance actions. Qualitative requirements for reliability: reliability requirements that cannot be described by quantifiable indexes; requirements for operational reliability; design requirements for reliability of specific products, such as simplified design, redundancy design, derating design and allowance design, environmental protection design, thermal design, electromagnetic compatibility design, ergonomics design, and application of mature technology and selection and control of components/parts; and protective or preventive measures and requirements around failures that will or may jeopardize the system. Factors affecting computer performance Date Posted: 10/24/2012 3:25:45 AM. 1.2.4 Factors Affecting RA… A scientific approach to maintainability should include good maintainability principles and guidelines; controlling mechanisms to ensure that maintainability is built in; simple and straightforward maintainability measuring methods that mean fewer and less complicated tasks during the design process and other processes; good interaction between design and maintainability professionals; and good record keeping to allow statistical analyses and reviews of maintainability action effectiveness. The selection of best maintainability model is prime concern for developing quality software system. The three main components of equipment downtime are logistic time, administrative time, and active repair time [20]. The qualitative requirements of RAMS define the RAMS requirements of a product in nonquantitative ways. Maintainability prediction should be accomplished immediately following definition of the basic system. T1 - Surveying the factors that influence maintainability: research design.

factors affecting maintainability

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