Software metrics: Software quality metrics for distributed systems

Software quality metrics was extended to cover distributed computer systems. Emphasis is placed on studying embedded computer systems and on viewing them within a system life cycle. The hierarchy of quality factors, criteria, and metrics was maintained. New software quality factors were added, including survivability, expandability, and evolvability

A Quantitative Approach to Assessing System Evolvability

When selecting a system from multiple candidates, the customer seeks the one that best meets his or her needs. Recently the desire for evolvable systems has become more important and engineers are striving to develop systems that accommodate this need. In response to this search for evolvability, we present a historical perspective on evolvability, propose a refined definition of evolvability, and develop a quantitative method for measuring this property. We address this quantitative methodology from both a theoretical and practical perspective. This quantitative model is then applied to the problem of evolving a lunar mission to a Mars mission as a case study

Investigating Relationships and Semantic Sets amongst System Lifecycle Properties (Ilities)

The ilities are properties of engineering systems that often manifest and determine value after a system is put into initial use (e.g. resilience, interoperability, flexibility). Rather than being primary functional requirements, these properties concern wider system impacts with respect to time and stakeholders. Over the past decade there has been increasing attention to ilities in industry, government and academia. Our research suggests that investigating ilities in sets may be more meaningful than study of single ilities in isolation. Some ilities are closely related and do in fact form semantic sets. Here, we use two methods to investigate over twenty ilities in terms of their prevalence and their interrelationships. We look for trends related to ilities of interest in relation to system type and an understanding of their collective use. First, we conducted a prevalence analysis of 22 ilities using both the internet as well as the Compendex/Inspec database as a source. We found over 1,275,000 scientific articles published between 1884 and 2010 and over 1.9 billion hits on the internet, exposing a clear prevalence-based ranking of ilities. Two questions we seek to address are: why and how are the ilities related to one another, and what can we do with this information. Initial steps to answer the first question include a 2-tupel-correlation matrix analysis that exposes the strongest relationships amongst ilities based on concurrent usage. Moreover, we conducted some preliminary experiments that indicate that a hierarchy of ilities with a few major groupings may be most useful. The overall objective for this research is to develop a formalframework and prescriptive guidance for effectively incorporating sets of ilities intothe design of complex engineering systems

Reconfigurability Function Deployment in Software Development

In the forthcoming highly dynamic and complex business environment high-speed and cost-effective development of software applications for targeting a precise, unique and momentary set of requirements (no more-no less) associated to a customized business case will bring sig-nificant benefits both for producers and users. This requires a life cycle change-oriented ap-proach in software development. In this respect, designing software with intrinsic evolutionary resources for reconfiguration represents the sound approach. A methodology for concurrent deployment of reconfigurability characteristics in software applications is introduced in this paper. Its potential is exemplified in a case study dealing with web-based software tools to support systematic product innovation projects.Reconfigurability, Software Development, Innovation, TRIZ, RAD

Lunar Applications in Reconfigurable Computing

NASA s Constellation Program is developing a lunar surface outpost in which reconfigurable computing will play a significant role. Reconfigurable systems provide a number of benefits over conventional software-based implementations including performance and power efficiency, while the use of standardized reconfigurable hardware provides opportunities to reduce logistical overhead. The current vision for the lunar surface architecture includes habitation, mobility, and communications systems, each of which greatly benefit from reconfigurable hardware in applications including video processing, natural feature recognition, data formatting, IP offload processing, and embedded control systems. In deploying reprogrammable hardware, considerations similar to those of software systems must be managed. There needs to be a mechanism for discovery enabling applications to locate and utilize the available resources. Also, application interfaces are needed to provide for both configuring the resources as well as transferring data between the application and the reconfigurable hardware. Each of these topics are explored in the context of deploying reconfigurable resources as an integral aspect of the lunar exploration architecture

Empirically characterizing evolvability and changeability in engineering systems

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012."June 2012." Cataloged from PDF version of thesis.Includes bibliographical references (p. 205-212).The beginning phases of system development and conceptual design require careful consideration, as these decisions will have significant influence on system lifetime performance and are often made with incomplete system knowledge. Decision makers may improve their capacity to discriminate between system concepts and design choices by measuring a system's "ilities" such as changeability, evolvability, and survivability. These ilities may enable systems to respond to perturbations in the design space, context space, and needs space in order to ensure system functionality and adequate performance over time. A system may be designed to change in response to perturbations, or remain statically robust/survivable to perturbations in order to avoid deficiencies or failures. This research attempts to analyze the mechanisms that allow system changes to occur. More specifically, this research will further the characterization of system changeability and evolvability and ultimately provide a structured and meaningful way of classifying system characteristics often described as "ilities". Value sustainment is proposed as an ultimate goal of systems, providing value in spite of perturbations in design, context, or needs. The premise of value sustainment is investigated through four distinct research thrusts: 1) a basis for defining system changes and ilities; 2) a system change examples database with categorical cluster analysis case research; 3) epoch-shift, impact, response, outcome case research; and 4) expert interviews case research. Focusing on change-related ilities, this research proposes constructs for identifying and enabling vague, yet desirable, system properties. Evolvability is characterized as a subset of changeability and defined as the ability of an architecture to be inherited and changed across generations [over time], with a set of ten proposed design principles including decentralization, redundancy, targeted modularity, scalability, integrability, reconfigurability, mimicry, leverage ancestry, disruptive architectural overhaul, and resourceful exaptation.by Jay Clark Beesemyer, Jr.S.M

Reconfigurability in space systems : architecting framework and case studies

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.Includes bibliographical references (p. 247-257).Reconfigurability in engineered systems is of increasing interest particularly in Aerospace Systems since it allows for resource efficiency, evolvability, and enhanced survivability. Although it is often regarded as a desirable quality for a system, it has traditionally been difficult to quantitatively analyze its effects on various system properties in the early design stage. In order to allow for gaining an in-depth understanding of the various aspects of reconfigurability and its relationship with a system's architecture, a framework encompassing a set of definitions, metrics, and methods has been proposed. Two different modeling schemes, based on Markov models and controls theory, are first developed to show how the states and time aspects of reconfigurable systems can be naturally modeled and studied. An analytical model for quantifying the effect of reconfigurability on mission logistics, specifically spare parts demands, is formulated and it is shown through one specific example that reconfigurable parts can allow for 33-50% mass reduction. The system availability, however, becomes very sensitive to the reliability of the parts. Two case studies are then used for detailed illustration of the application of the developed framework.(cont.) In the first case study, the effect of reconfigurability on a fleet of planetary surface vehicles for a surface exploration mission are analyzed. It is found that a fleet of reconfigurable vehicles can allow for a mass savings of up to 27% and their expected transport capability degradation is almost three times lower as compared to a fleet of non-reconfigurable vehicles. In the second case-study, the reconfiguration of low earth-orbit communication satellite constellations is considered for evolving to higher capacity levels. It is found that reconfiguring a previously deployed constellation can be a viable option only for certain capacity levels and multi-payload launch capability scenarios. In addition to the high level 'ility' perspectives, a lower level design assessment is also carried out through a survey of 33 representative reconfigurable systems. It is found that on average, for commercial items the cost of reconfigurability is 35%, and the average useful state occupancy time is always at least 10 times the reconfiguration time of the system. Based on the illustrative results of the case studies, and generalization of empirical data, a few principles and guidelines for design for reconfigurability are proposed.by Afreen Siddiqi.Ph.D

Collaborative environment to support a professional community

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresRecent manufacturing roadmaps stress current production systems limitations, emphasizing social, economic and ecologic consequences for Europe of a non-evolution to sustainable Production Systems. Hence, both academic institutions and enterprises are committed to develop solutions that would endow enterprises to survive in nowadays’ extremely competitive business environment. A research effort is being carried on by the Evolvable Production Systems consortium towards attaining Production Systems that can cope with current technological, economical, ecological and social demands fulfilling recent roadmaps. Nevertheless research success depends on attaining consensus in the scientific community and therefore an accurate critical mass support is required in the whole process. The main goal of this thesis is the development of a Collaborative Environment Tool to assist Evolvable Production Systems consortium in such research efforts and to enhance Evolvable Assembly Systems paradigm dissemination. This work resulted in EASET (Evolvable Assembly Systems Environment Tool), a collaborative environment tool which promotes EAS dissemination and brings forth improvements through the raise of critical mass and collaboration between entities