DOCSLIB.ORG

Improvement of System Availability Using Reliability and Maintainability Analysis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Improvement of System Availability Using Reliability and Maintainability Analysis 2005:92 LICENTIATE T H E SI S Improvement of System Availability Using Reliability and Maintainability Analysis Javad Barabady Luleå University of Technology Division of Operation and Maintenance Engineering 2005:92|: 02-757|: -c -- 05⁄92 -- Improvement of System Availability Using Reliability and Maintainability Analysis Javad Barabady Division of Operation and Maintenance Engineering Luleå University of Technology December 2005 PREFACE AND ACKNOWLEDGMENTS The research work presented in this thesis has been carried out at the Division of Operation and Maintenance Engineering, under the supervision of Professor Uday Kumar, Head, Divi- sion of Operation and Maintenance Engineering. It was carried out at Luleå University of Technology during the period October 2003 to December 2004. The thesis contains four pa- pers. I wish to express my sincere thanks to my supervisor Professor Uday Kumar for introducing me to the subject area of reliability and availability and maintainability, for his thoughtful su- pervision, steady support, guidance, and for making available critical facilities throughout the course of this work. I am also thankful to Professor Per-Anders Akersten for his comments to improve the manuscript and content of the research work. I am grateful to the government of Iran to provide me with financial support to undertake this research work. I would also like to thank my colleagues Behzad Ghodrati, Aditya Parida, Arne Nissen, to- gether with all other colleagues in my department. They encouraged me through discussions and valuable advice. I would also like to thank my Iranian friends especially to Behzad Ghodrati and his wife Saei- deh for their hospitality during my study in Sweden. I would like to express my thanks to my wife Hamideh and our daughter Maryam, for their endless support and patience. I take this opportunity to express my deep and heartfelt gratitude to my mother Fatemeh and my father Mohammad. They have unselfishly given so much to create the opportunity for me both to grow as a person and to be able to secure an outstanding education. Finally I wish to express my gratitude to all my family members, especially my brothers and my sister for their support, kindness, and encouragement. Javad Barabady December 2005 Luleå, Sweden. i ii ABSTRACT System reliability, maintainability and availability have assumed great significance in recent years due to a competitive environment and overall operating and production costs. Perform- ance of equipment depends on reliability and availability of the equipment used, operating en- vironment, maintenance efficiency, operation process and technical expertise of operators, etc. When the reliability and availability of system are low, efforts are needed to improve them by reducing the failure rate or increasing the repair rate for each component or subsystem. The aim of this research study is to analyse operating reliability and availability for a system with periodically inspected and maintained components subjected to some maintenance strat- egy and find some importance measures that show the criticality of the components or subsys- tems. This analysis has helped to identify the critical and sensitive subsystems or components of the system that need more attention for improvement. In this research work we suggest a methodology for improving the availability of a repairable system. In the methodology, the concept of importance measures must be used to prioritize the components or subsystems for availability improvement processes. Availability importance measures show the criticality of each component based on different points of view such as availability, repair rate, and failure rate of each component. The reliability and availability of repairable systems can be improved by applying appropriate maintenance strategies; therefore a model is developed for selecting the most suitable maintenance strategies on the based of analysis of reliability and maintainability characteristic of the operating system. The empirical data of two crushing plants at the Jajarm bauxite mine of Iran are used as a case study for reli- ability and availability analysis. The study shows that the reliability and maintainability analysis is very useful for deciding maintenance intervals, planning and organizing maintenance. The results show that availabil- ity and reliability importance measures can be used as a guideline for managing the efforts for reliability and availability improvement of a system. Keywords, Reliability, Availability and Maintainability, Maintenance, repairable system, Op- timization, Importance Measure iii iv LIST OF APPENDED PAPERS Paper I: Barabady, J. (2005), “Reliability and maintainability analysis of crushing plants in Jajarm bauxite mine of Iran”, Proceedings of the Annual Reliability and Maintainability Sym- posium, P.109 – 115. Paper II: Barabady, J., Kumar, U. (2005), “Reliability analysis of mining equipment: A case study of a crushing plant at the Jajarm bauxite mine of Iran”, Submitted for publication in Journal of Reliability Engineering and System Safety. Paper III: Barabady, J., Kumar, U. (2005), “Maintenance schedule by using reliability analy- sis: A case study at Jajarm bauxite mine of Iran”, 20th World Mining Congress & Expo 2005, 7-11 November, Tehran, Iran. Paper IV: Barabady, J., Kumar, U. (2005), “Availability allocation through importance meas- ures”, Submitted for publication in a Journal. v vi TABLE OF CONTENTS 1 Introduction ……………………………………….…………….….………… 1 1.1 Background ……………………………………………….…………… 1 1.2 Research Problem……………………...……….……………………… 4 1.3 Research Questions ……………………..……….…………….……… 4 1.4 Purpose of the Research Study ……………………………….……… 5 1.5 Objective of the Research Study……………………………………… 5 1.5 Limitation of the Research Study……………………...……….……… 5 1.6 Structure of the Research Study ………..………….……………….… 5 2 Research Approach and Methodology……………..…….…….….………… 7 2.1 Introduction …………………………………………….……………… 7 2.2 Research Purpose …………………………………………………....… 7 2.3 Research Approach ……………………………...……………....…….. 8 2.3.1 Induction, Deduction, or Abduction ...................................…... 8 2.3.2 Qualitative or Quantitative ………………...…….…………… 9 2.4 Research Strategy ………………………………………….…....……. 10 2.5 Data Collection…………………………………………………….…...…….. 11 2.6 Data Analyzing …………………………………………..….………. 12 2.7 Reliability and Validity………………………………………….…… 14 2.8 Research Design ……………………………………………………….. 15 2.7 Research Process …………………………………….………. 15 3 Theoretical frame of reference (Literature Review) ……………………… 17 3.1 Introduction to RAM ……………………………………………....… 17 3.2 Some Basic Definition ……………………………………………….. 19 3.2.1 Reliability………………………………….………………...... 19 3.2.2 Maintainability …………...………………..……………….… 21 3.2.3 Availability ……………………………………..……….…… 23 3.2.4 Maintenance…………………………………….….…….…… 25 3.3 Overview of the RAM Process …………....……………….….….….. 27 vii 3.4 RAM Information System ………………….………………….…….. 29 3.5 Reliability, Availability, Maintainability Improvement …………...... 30 4 Summary of Appended Papers ……….. ……………….….….…… 33 4.1 Paper 1 ………………………………………………………………… 33 4.2 Paper 2 ………………………………………………………………… 33 4.3 Paper 3 ………………………………………………………………… 34 4.4 Paper 4 ………………………………………………………………… 35 5 Result, Discussion and Conclusions ………………..………….….………… 37 5.1 Research Results………………………………………………………. 37 5.2 Discussion ………………..…………………………………………… 37 5.2.1 RAM Improvement ………....………………………………… 37 5.2.2 Concept of Importance Measures ……………………………... 39 5.2.2.1 Reliability Importance Measures …………...……..... 39 5.2.2.2 Availability Importance Measures …………..……… 40 5.2.3 Maintenance Strategy Based on Reliability …………….…….. 42 5.2.4 Self Criticism of the Research ……..…...…………………….. 44 5.3 Conclusions and Future Research ……………………….……….…… 45 5.3.1 Conclusions……………………………...…………………..… 45 5.3.2 Research Contribution ……………..…………...…………….. 46 5.3.2 Suggestion for Further Research …………….....….. 46 References ………………………………………………………………….………… 47 Appended Papers ………………………………………………………….………… 51 viii NOTATION AND ABBREVIATION ΔC Cost needed to improve repair rate of the component i as Δμ μi i i I A Availability importance measure of component i Ci Cost of an inspection λ(t) Failure rate function β Shape parameter I i Availability importance measure of component i based on the failure rate A,λi I i Availability importance measure of component i based on the repair rate A,μi ΔC Cost needed to improve the failure rate of the component i as Δλ λi i i I R Reliability importance measure of the component i ∂C Variation of availability improvement cost with respect to failure rate of component i ∂λi ∂C Variation of availability improvement cost with respect to repair rate of component i ∂μi A (t) Instant availability of system at time t Ai Functional availability or inherent availability Ao Operational availability Aa Achieved availability C Budget for availability improvement CBM Condition based maintenance CM Corrective maintenance ECC Expected cost of corrective maintenance ECI Expected cost of inspection ECP Expected cost of preventive maintenance F(t) Cumulative distribution function (CDF) f(t) Probability density function(PDF) FTM Fixed time maintenance MFTT Mean function test time MTBF Mean time between failures MTTR Mean time to repair PM Preventive maintenance RAM Reliability, Availability and maintainability RAMI Reliability, Availability and maintainability improvement SSC Structure, system or component TBF Time between failures TBM Time based maintenance ix ti Running time at the occurrence of failure
Load more

Recommended publications
  • Jackson: Choosing a Methodology: Philosophical Underpinning
    JACKSON: CHOOSING A METHODOLOGY: PHILOSOPHICAL UNDERPINNING Choosing a Methodology: Philosophical Practitioner Research Underpinning In Higher Education Copyright © 2013 University of Cumbria Vol 7 (1) pages 49-62 Elizabeth Jackson University of Cumbria [email protected] Abstract As a university lecturer, I find that a frequent question raised by Masters students concerns the methodology chosen for research and the rationale required in dissertations. This paper unpicks some of the philosophical coherence that can inform choices to be made regarding methodology and a well-thought out rationale that can add to the rigour of a research project. It considers the conceptual framework for research including the ontological and epistemological perspectives that are pertinent in choosing a methodology and subsequently the methods to be used. The discussion is exemplified using a concrete example of a research project in order to contextualise theory within practice. Key words Ontology; epistemology; positionality; relationality; methodology; method. Introduction This paper arises from work with students writing Masters dissertations who frequently express confusion and doubt about how appropriate methodology is chosen for research. It will be argued here that consideration of philosophical underpinning can be crucial for both shaping research design and for explaining approaches taken in order to support credibility of research outcomes. It is beneficial, within the unique context of the research, for the researcher to carefully
    [Show full text]
  • Applications of Systems Engineering to the Research, Design, And
    Applications of Systems Engineering to the Research, Design, and Development of Wind Energy Systems K. Dykes and R. Meadows With contributions from: F. Felker, P. Graf, M. Hand, M. Lunacek, J. Michalakes, P. Moriarty, W. Musial, and P. Veers NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Technical Report NREL/TP-5000-52616 December 2011 Contract No. DE -AC36-08GO28308 Applications of Systems Engineering to the Research, Design, and Development of Wind Energy Systems Authors: K. Dykes and R. Meadows With contributions from: F. Felker, P. Graf, M. Hand, M. Lunacek, J. Michalakes, P. Moriarty, W. Musial, and P. Veers Prepared under Task No. WE11.0341 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. National Renewable Energy Laboratory Technical Report NREL/TP-5000-52616 1617 Cole Boulevard Golden, Colorado 80401 December 2011 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof.
    [Show full text]
  • ASSESSING the MAINTAINABILITY of C++ SOURCE CODE by MARIUS SUNDBAKKEN a Thesis Submitted in Partial Fulfillment of the Requireme
    ASSESSING THE MAINTAINABILITY OF C++ SOURCE CODE By MARIUS SUNDBAKKEN A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science WASHINGTON STATE UNIVERSITY School of Electrical Engineering and Computer Science DECEMBER 2001 To the Faculty of Washington State University: The members of the Committee appointed to examine the thesis of MARIUS SUNDBAKKEN find it satisfactory and recommend that it be accepted. Chair ii ASSESSING THE MAINTAINABILITY OF C++ SOURCE CODE Abstract by Marius Sundbakken, M.S. Washington State University December 2001 Chair: David Bakken Maintenance refers to the modifications made to software systems after their first release. It is not possible to develop a significant software system that does not need maintenance because change, and hence maintenance, is an inherent characteristic of software systems. It has been estimated that it costs 80% more to maintain software than to develop it. Clearly, maintenance is the major expense in the lifetime of a software product. Predicting the maintenance effort is therefore vital for cost-effective design and development. Automated techniques that can quantify the maintainability of object- oriented designs would be very useful. Models based on metrics for object-oriented source code are necessary to assess software quality and predict engineering effort. This thesis will look at C++, one of the most widely used object-oriented programming languages in academia and industry today. Metrics based models that assess the maintainability of the source code using object-oriented software metrics are developed. iii Table of Contents 1. Introduction .................................................................................................................1 1.1. Maintenance and Maintainability.......................................................................
    [Show full text]
  • Choosing a Mixed Methods Design
    04-Creswell (Designing)-45025.qxd 5/16/2006 8:35 PM Page 58 CHAPTER 4 CHOOSING A MIXED METHODS DESIGN esearch designs are procedures for collecting, analyzing, interpreting, and reporting data in research studies. They represent different mod- R els for doing research, and these models have distinct names and procedures associated with them. Rigorous research designs are important because they guide the methods decisions that researchers must make dur- ing their studies and set the logic by which they make interpretations at the end of studies. Once a researcher has selected a mixed methods approach for a study, the next step is to decide on the specific design that best addresses the research problem. What designs are available, and how do researchers decide which one is appropriate for their studies? Mixed methods researchers need to be acquainted with the major types of mixed methods designs and the common variants among these designs. Important considerations when choosing designs are knowing the intent, the procedures, and the strengths and challenges associated with each design. Researchers also need to be familiar with the timing, weighting, and mixing decisions that are made in each of the different mixed methods designs. This chapter will address • The classifications of designs in the literature • The four major types of mixed methods designs, including their intent, key procedures, common variants, and inherent strengths and challenges 58 04-Creswell (Designing)-45025.qxd 5/16/2006 8:35 PM Page 59 Choosing a Mixed Methods Design–●–59 • Factors such as timing, weighting, and mixing, which influence the choice of an appropriate design CLASSIFICATIONS OF MIXED METHODS DESIGNS Researchers benefit from being familiar with the numerous classifications of mixed methods designs found in the literature.
    [Show full text]
  • Environmental Systems Analysis Tools for Decision-Making
    Environmental systems analysis tools for decision-making LCA and Swedish waste management as an example Åsa Moberg Licentiate thesis Royal Institute of Technology Department of Urban Planning and Environment Environmental Strategies Research Stockholm 2006 Titel: Environmental systems analysis tools for decision‐making LCA and Swedish waste management as an example Author: Åsa Moberg Cover page photo: Marianne Lockner TRITA‐SOM 06‐002 ISSN 1653‐6126 ISRN KTH/SOM/‐‐06/002‐‐SE ISBN 91‐7178‐304‐0 Printed in Sweden by US AB, Stockholm, 2006 2 Abstract Decisions are made based on information of different kinds. Several tools have been developed to facilitate the inclusion of environmental aspects in decision‐making on different levels. Which tool to use in a specific decision‐making situation depends on the decision context. This thesis discusses the choice between different environmental systems analysis (ESA) tools and suggests that key factors influencing the choice of ESA tool are object of study, impacts considered and information type regarding site‐specificity and according to the DPSIR‐framework. Waste management in Sweden is used as an example to illustrate decision‐making situations, but discussions concerning choice of tools are also thought to be of general concern. It is suggested that there is a need for a number of ESA tools in waste management decision‐making. Procedural tools like Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA) should be used e.g. by companies applying for development of waste management facilities and by public authorities preparing plans and programmes. Within these procedural tools analytical tools providing relevant information could be used, e.g.
    [Show full text]
  • A Quantitative Reliability, Maintainability and Supportability Approach for NASA's Second Generation Reusable Launch Vehicle
    A Quantitative Reliability, Maintainability and Supportability Approach for NASA's Second Generation Reusable Launch Vehicle Fayssai M. Safie, Ph. D. Marshall Space Flight Center Huntsville, Alabama Tel: 256-544-5278 E-mail: Fayssal.Safie @ msfc.nasa.gov Charles Daniel, Ph.D. Marshall Space Flight Center Huntsville, Alabama Tel: 256-544-5278 E-mail: Charles.Daniel @msfc.nasa.gov Prince Kalia Raytheon ITSS Marshall Space Flight Center Huntsville, Alabama Tel: 256-544-6871 E-mail: Prince.Kalia @ msfc.nasa.gov ABSTRACT The United States National Aeronautics and Space Administration (NASA) is in the midst of a 10-year Second Generation Reusable Launch Vehicle (RLV) program to improve its space transportation capabilities for both cargo and crewed missions. The objectives of the program are to: significantly increase safety and reliability, reduce the cost of accessing low-earth orbit, attempt to leverage commercial launch capabilities, and provide a growth path for manned space exploration. The safety, reliability and life cycle cost of the next generation vehicles are major concerns, and NASA aims to achieve orders of magnitude improvement in these areas. To get these significant improvements, requires a rigorous process that addresses Reliability, Maintainability and Supportability (RMS) and safety through all the phases of the life cycle of the program. This paper discusses the RMS process being implemented for the Second Generation RLV program. 1.0 INTRODUCTION The 2nd Generation RLV program has in place quantitative Level-I RMS, and cost requirements [Ref 1] as shown in Table 1, a paradigm shift from the Space Shuttle program. This paradigm shift is generating a change in how space flight system design is approached.
    [Show full text]
  • Software Quality Management
    Software Quality Management 2004-2005 Marco Scotto ([email protected]) Software Quality Management Contents ¾Definitions ¾Quality of the software product ¾Special features of software ¾ Early software quality models •Boehm model • McCall model ¾ Standard ISO 9126 Software Quality Management 2 Definitions ¾ Software: intellectual product consisting of information stored on a storage device (ISO/DIS 9000: 2000) • Software may occur as concepts, transactions, procedures. One example of software is a computer program • Software is "intellectual creation comprising the programs, procedures, rules and any associated documentation pertaining to the operation of a data processing system" •A software product is the "complete set of computer programs, procedures and associated documentation and data designated for delivery to a user" [ISO 9000-3] • Software is independent of the medium on which it is recorded Software Quality Management 3 Quality of the software product ¾The product should, on the highest level… • Ensure the satisfaction of the user needs • Ensure its proper use ¾ Earlier: 1 developer, 1 user • The program should run and produce results similar to those expected ¾ Later: more developers, more users • Need to economical use of the storage devices • Understandability, portability • User-friendliness, learnability ¾ Nowadays: • Efficiency, reliability, no errors, able to restart without using data Software Quality Management 4 Special features of software (1/6) ¾ Why is software ”different”? • Does not really have “physical” existence
    [Show full text]
  • Software Maintainability and Usability in Agile Environment
    Software Maintainability and Usability in Agile Environment {tag} {/tag} International Journal of Computer Applications © 2013 by IJCA Journal Volume 68 - Number 4 Year of Publication: 2013 Authors: Monika Agarwal Rana Majumdar 10.5120/11569-6873 {bibtex}pxc3886873.bib{/bibtex} Abstract This research is based on software maintainability and usability in the agile environment. Maintainability of the system is the ability to undergo changes relatively easily. These changes can affect components, services, interfaces and functionality when adding or changing functions, errors, and respond to business needs. Usability is defined as the application that meets the requirements of users and consumers by providing an intuitive, easy to locate and globalize and provides good access for disabled users and leads to a good overall user experience. In the conventional method of the software development, there are many metrics to calculate the maintenance and use of software. This research is to determine whether the same measures apply to Agile, or there is a need to change some metrics used for the agile environment. The goal of software engineering is to develop good quality maintainable software in schedule and budget. Inflated software costing, delayed time frame, or not meeting quality standards express a failure. A survey suggests about 45% of software fails due to the lack of quality. It is therefore one of the most important aspects for the success of software. Refer ences 1 / 3 Software Maintainability and Usability in Agile Environment - P. Antonellis, D. Antoniou, Y. Kanellopoulos, C. Makris, E. Theodoridis, C. Tjortjis, and N. Tsirakis, "A data mining methodology for evaluating maintainability according to ISO/IEC-9126 software engineering – product quality standard," in Special Session on System Quality and Maintainability - SQM2007, 2007.
    [Show full text]
  • 3 Research Philosophy and Research Design
    Research Philosophy 3 and Research Design Introduction In the introductory chapter, developing self-awareness was a key pro- cess outlined and it was stated that it is possible you have assumed that the way you view the world is the same as the way that everybody else views the world. The term ‘common sense’ was used in this discussion. We noted then, you could believe it is common sense that the way you look at the world is the same way that others look at it. However, we also saw earlier that one person’s common sense is not necessarily the same as another’s! If we accept that there are likely to be differences between people’s view of the world, it may not come as a surprise that the way some researchers view the world, is very different from other’s views. Research philosophies The idea that there are different views of the world, and the processes that operate within it, is part of what is known as philosophy. Philosophy is concerned with views about how the world works and, as an academic subject, focuses, primarily, on reality, knowledge and existence. Our individual view of the world is closely linked to what we perceive as reality. On a day-to-day basis outside of your academic work, it would be unusual to think often about the way you perceive reality and the world around you. However, in relation to your dissertation, it is very important to realise how you perceive reality. Your individual percep- tion of reality affects how you gain knowledge of the world, and how you act within it.
    [Show full text]
  • CISM160 Systems Analysis and Design Course Syllabus
    ATLANTIC CAPE COMMUNITY COLLEGE ISAS DEPARTMENT COURSE SYLLABUS COURSE TITLE: CISM160 Systems Analysis and Design Instructor: Dr. Otto Hernandez Office: A-142 Phone: 609-343-4978 eMail: [email protected] REQUIRED TEXTBOOK AND MATERIALS: Essentials of Systems Analysis and Design. Author: Valacich; Edition: 6th; ISBN: 9780133546231 COURSE DESCRIPTION: Investigation of information systems with respect to their existence and identification and development of needed informational improvements within an organization. Recommended methods and procedures considering computer involvement are reviewed, designed and implemented using the case-study approach PRE-REQUISITE: one of the following: CISM135, CISM154 or CISM174 ADA STATEMENT: As per the Americans with Disabilities Act (ADA), reasonable accommodations can be provided to students who present current documentation (within five years) of a disability to Atlantic Cape Community College’s Center for Accessibility, located on the first floor of “J” Building in the Counseling and Support Services department (Mays Landing campus). Reasonable accommodations cannot be provided for a course until the student registers with the Center for Accessibility. For more information, please contact the Center for Accessibility via email at [email protected] call 609-343- 5680. LEARNING GOALS & OBJECTIVES: A) Understanding the Systems Development Environment 1. Define information systems analysis and design. 2. Define and discuss the modern approach to systems analysis and design. 3. Illustrate how systems development extends to different types of information systems and not just transaction processing systems. 4. Introduce the traditional information systems development life cycle, which serves as the basis for the organization of the material in this book. 5. Show that the life cycle is a flexible basis for systems analysis and design and that it can support many different tools and techniques, such as prototyping and JAD.
    [Show full text]
  • Fashion Designers' Decision-Making Process
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2013 Fashion designers' decision-making process: The influence of cultural values and personal experience in the creative design process Ja-Young Hwang Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Art and Design Commons Recommended Citation Hwang, Ja-Young, "Fashion designers' decision-making process: The influence of cultural values and personal experience in the creative design process" (2013). Graduate Theses and Dissertations. 13638. https://lib.dr.iastate.edu/etd/13638 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Fashion designers’ decision-making process: The influence of cultural values and personal experience in the creative design process by Ja -Young Hwang A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Apparel, Merchandising, and Design Program of Study Committee: Mary Lynn Damhorst, Co-Major Professor Eulanda Sanders, Co-Major Professor Sara B. Marcketti Cindy Gould Barbara Caldwell Iowa State University Ames, Iowa 2013 Copyright © Ja Young Hwang, 2013. All rights
    [Show full text]
  • Adaptability Evaluation at Software Architecture Level Pentti Tarvainen*
    The Open Software Engineering Journal, 2008, 2, 1-30 1 Open Access Adaptability Evaluation at Software Architecture Level Pentti Tarvainen* VTT Technical Research Centre of Finland, Kaitoväylä 1, P.O. Box 1100, FIN-90571 Oulu, Finland Abstract: Quality of software is one of the major issues in software intensive systems and it is important to analyze it as early as possible. An increasingly important quality attribute of complex software systems is adaptability. Software archi- tecture for adaptive software systems should be flexible enough to allow components to change their behaviors depending upon the environmental and stakeholders' changes and goals of the system. Evaluating adaptability at software architec- ture level to identify the weaknesses of the architecture and further to improve adaptability of the architecture are very important tasks for software architects today. Our contribution is an Adaptability Evaluation Method (AEM) that defines, before system implementation, how adaptability requirements can be negotiated and mapped to the architecture, how they can be represented in architectural models, and how the architecture can be evaluated and analyzed in order to validate whether or not the requirements are met. AEM fills the gap from requirements engineering to evaluation and provides an approach for adaptability evaluation at the software architecture level. In this paper AEM is described and validated with a real-world wireless environment control system. Furthermore, adaptability aspects, role of quality attributes, and diversity of adaptability definitions at software architecture level are discussed. Keywords: Adaptability, adaptation, adaptive software architecture, software quality, software quality attribute. INTRODUCTION understand the system [6]. Examples of design decisions are the decisions such as “we shall separate user interface from Today, quality of a software system plays an increasingly the rest of the application to make both user interface and important role in the domain of software engineering.
    [Show full text]