The purpose of Reliability and Maintainability (R&M) engineering (Maintainability includes Built-In-Test (BIT)) is to influence system design in order to increase mission capability and availability and decrease logistics burden and cost over a system’s life cycle. Planning is not a unique tool for reliability engineers. 2. Consider the use of modular, sealed assemblies (and lubricated components). Designing for Reliability, Maintainability, and Sustainability (RM&S) in Military Jet Fighter Aircraft Engines by Lael S. Herbert B.S. The discipline’s first concerns were electronic and mechanical components (Ebeling, 2010). 2. b. The origins of contemporary reliability engineering can be traced to World War II. The prediction of software maintainability has emerged as an important research topic to address industry expectations for reducing costs, in particular, maintenance costs. But what if those costs could be alleviated - and performance optimized - by encouraging facility professionals to provide input during the design phase of the project? Maintainability is a key driving element in the effective support and upkeep of the system as well as providing the ability to modify and upgrade the system throughout its lifetime. endstream Overview. 5 0 obj 4. 12.2 DESIGN FOR MAINTAINABILITY DESIGN CONSIDERATIONS {A} Factors that should be considered when designing for maintainability are provided below. Define the maintainability requirements quantitatively. Maintainability testing shall use a model of the maintainability requirements of the software/system. endobj Reliability, maintainability, and availability (RAM) are three system attributes that are of great interest to systems engineers, logisticians, and users. Reverse engineering involves the following steps. A measure of ‘effort’ must include time, resources and expertise. 3. Q De Weck—Engineering Systems 4 Life-Cycle Properties of Engineering Systems: The Ilities In the epoch of great inventions and artifacts, the implicit mandate of the engineer and inventor was to “design for first use.” The aim was to design and build an artifact that would “work” and fulfill its primary function Implement the designs and test that they meet the required levels. Most software engineers would think of some combination of testability, understandability and modifiability of code, as measures of maintainability. Reliability assessment, training, and data collection and reporting are examples of program level tools. 4. Are the most common operations streamlined to be performed quickly? endobj The maintainability index is calculated with certain formulae from lines-of-code measures, McCabe measures and Halstead complexity measures . This means that you should design your classes in such a way that each class should have a single purpose. Collectively, they affect both the utility and the life-cycle costs of a product or system. Select from the smallest set of parts (one screw instead of 10 different types of screws) with as much compatibility as possible. CHAPTER 5 - Specific Maintainability Design Considerations. The design group must consider what the future may hold and make reasonable accommodations. Engineering Maintainability How to Design for Reliability and Easy Maintenance. Like other uses of program or project planning, you use planning tools to organize the available resources to identify and solve reliability related problems. 4 0 obj Developers take care of maintainability by continuously adapting software to meet new customer requirements and address problems faced by customers. Software maintenance is a phase in the software development cycle that starts after the customer has received the product. Maintaining software once implemented on the end-user side is laborious and, over its lifetime, is most often considerably more expensive than the initial software development. Do validation and error messages make sense? Closely related concepts in the software engineering domain are evolvability, modifiability, technical debt, and code smells . Design to use common fixtures, fittings (to minimise tooling) and standard parts. Maintainability is the degree to which a product allows safe, quick and easy replacement of its component parts. By these modifications to the environment, changes can occur in the other parts of the software. << /Type /Page /Parent 7 0 R /Resources 3 0 R /Contents 2 0 R /MediaBox (for example, the ‘desktop’ is a metaphor) 2. Is there a UI metaphor that I am using to help users adapt? It is combination of five basic designing principles. 5, 3, 7, 8). A software product needs maintenance to support the new features that the users want or to change different types of functionalities of the system according to the customer demands. Your email address will not be published. This resource page presents a methodology that links operations and maintenance goals to the design process, and how it can be applied to any organization. The design constraints in ubiquitous computing (ubicomp) differ from those traditionally emphasized by the systems community: evolvability, long-term maintainability, and robustness to transient failures are essential, while scalability and performance are lesser concerns, due to the nature of ubicomp itself and the performance of today’s commodity equipment. 3 0 obj Can new users quickly adapt to the software without help? 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\" . It is embodied in the design of the product. A reliability projectfocuses on one pr… Cookies Policy, Rooted in Reliability: The Plant Performance Podcast, Product Development and Process Improvement, Musings on Reliability and Maintenance Topics, Equipment Risk and Reliability in Downhole Applications, Innovative Thinking in Reliability and Durability, 14 Ways to Acquire Reliability Engineering Knowledge, Reliability Analysis Methods online course, Reliability Centered Maintenance (RCM) Online Course, Root Cause Analysis and the 8D Corrective Action Process course, 5-day Reliability Green Belt ® Live Course, 5-day Reliability Black Belt ® Live Course, This site uses cookies to give you a better experience, analyze site traffic, and gain insight to products or offers that may interest you. A lack of maintainability will be evident as high product maintenance costs, long out-of service times, and possible injuries to maintenance engineers. More formally, the IEEE Standard Glossary of Software Engineering Terminology defines maintainability as: "The ease with which a software system or component can be modified to correct faults, improve performance or other attributes, or adapt to a changed environment." I have defined maintainability as: a measure of the effort required to change the functionality of application software. /Resources 6 0 R /Filter /FlateDecode >> Problems arise when a software generally exceeds timelines, budgets, and … Learn how we use cookies, how they work, and how to set your browser preferences by reading our. Reliability is the wellspring for the other RAM system attributes of availability and maintainability. 2 0 obj 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? Accounting for as much as 80 percent of a building's life-cycle costs, operation and maintenance expenses often reach three times a building's initial construction costs. (is it intuitive?) a. Non-Interference of Preventive Maintenance - Preventive maintenance should be minimized and require as little crew time as feasible. It improves maintainability by reducing variations of design and installation for maintenance personnel. Fritz Bauer defined it as 'the establishment and used standa… We care about your privacy and will not share, leak, loan or sell your personal information. << /ProcSet [ /PDF ] /XObject << /Fm1 5 0 R >> >> Specific Maintainability Design Considerations. Reliability, maintainability, and software quality have to be built into complex equipment and systems during the design and development phase. In general any software development manager is familiar with this definition of ‘effort’ as it applies to creating software. [0 0 612 792] >> Abstract. The key software design principles are as: SOILD. %PDF-1.3 Here is a list of human factors related, design for maintainability considerations: Consider maintenance from ‘cradle to grave’. Software maintenance in software engineering is the modification of a software product after delivery to correct faults, to improve performance or other attributes.. A common perception of maintenance is that it merely involves fixing defects.However, one study indicated that over 80% of maintenance effort is used for non-corrective actions. endobj Designing Software Metrics in Software Engineering By Dinesh Thakur An effective software metrics helps software engineers to identify shortcomings in the software development life cycle so that the software can be developed as per the user requirements, within estimated schedule and cost, with required quality level, and so on. << /Length 4 0 R /Filter /FlateDecode >> Reverse engineering is a useful technique when the software maintenance team is unable to understand the processes involved in the software system. The maintainability of software depends on a few different factors. Another aspect that is equally critical is the ability to understand the requirement, the “what” that is implemented by the code, the “how”. View our, Preventive Maintenance or PM Goals and Activities, Probability and Statistics for Reliability. Preventive maintenance: This type of maintenance includes modifications and updations to prevent future problems of the software. %��������� This has to be supported by analytical investigations (Chaps. Some questions to ask yourself to determine usability might be: 1. x��}]s$���{��|\E�����b���Cޕƚ=x��&�͒�*?�M�zW�IV�u� f,=L�T}yO^�~�����1�V��Wʥ�%;�W&��ǻ����f��?��x~?���ޟ���Z��Ov������� bV�G�v��J���f�/?��?���?ߌ��_e�F��~~^��{�q��S��=�p�=�bG��=c��u�al��t���!�p�r This paper then, will concentrate on maintainability and its integration into the system engineering and design process. Let's look at the various definitions of software engineering: 1. Standardize and Label Using recognized national, industry and company (if your customer has them) standards and codes is good practice. The maintainability testing shall be specified in terms of the effort required to effect a change under each of the following four categories: Corrective maintenance – Correcting problems. 1. x�+TT(c}�\C�|�@ 1�� Book chapter Full text access. Properly planned, R&M engineering reduces cost and schedule risks by preventing or identifying R&M deficiencies early in development.