Evaluating Maintainability Prejudices with a Large-Scale Study of Open-Source Projects

Exaggeration or context changes can render maintainability experience into prejudice. For example, JavaScript is often seen as least elegant language and hence of lowest maintainability. Such prejudice should not guide decisions without prior empirical validation. We formulated 10 hypotheses about maintainability based on prejudices and test them in a large set of open-source projects (6,897 GitHub repositories, 402 million lines, 5 programming languages). We operationalize maintainability with five static analysis metrics. We found that JavaScript code is not worse than other code, Java code shows higher maintainability than C# code and C code has longer methods than other code. The quality of interface documentation is better in Java code than in other code. Code developed by teams is not of higher and large code bases not of lower maintainability. Projects with high maintainability are not more popular or more often forked. Overall, most hypotheses are not supported by open-source data.Comment: 20 page

Space station data system analysis/architecture study. Task 2: Options development, DR-5. Volume 3: Programmatic options

Task 2 in the Space Station Data System (SSDS) Analysis/Architecture Study is the development of an information base that will support the conduct of trade studies and provide sufficient data to make design/programmatic decisions. This volume identifies the preferred options in the programmatic category and characterizes these options with respect to performance attributes, constraints, costs, and risks. The programmatic category includes methods used to administrate/manage the development, operation and maintenance of the SSDS. The specific areas discussed include standardization/commonality; systems management; and systems development, including hardware procurement, software development and system integration, test and verification

Project for the analysis of technology transfer Quarterly report, 13 Jul. - 12 Oct. 1968

Statistical characteristics of transfer data bank users, and outline of technology transfer and utilization instruction cours

Furniture for Later Life: Design Based on Older People’s Experiences of Furniture in Three Housing Forms

This thesis in industrial design concerns the challenges and possibilities in meeting demographic shifts and the presumed expectations of today’s and tomorrow’s older generations. The background is the lack of furniture that responds to the demands of older consumers and the lack of knowledge about relationships between people and furniture in their home environments and in various forms of elderly care environments. Generalizations made regarding old people's needs have proved to be too limited in scope to meet their needs and wishes. The purpose is to improve knowledge and awareness concerning the ways in which old people act on, are influenced by, reflect on and appreciate furniture in their homes. To reveal these relationships, three different housing forms have been studied and compared. The aim is to improve the conditions for design of furniture intended for old people and the housing forms in which they live with their own experiences as a point of departure. The overall approach is user-centered with an early focus on old people. A number of qualitative, descriptive studies were conducted to shed light on everyday relationships between old people and furniture. One common feature of the studies was interviews. In order to reach a deeper and more nuanced understanding, a combination of various data gathering methods has been applied in addition to the interviews. In total, 88 people participated in the studies. A qualitative cross-study content analysis was used to compare accounts regarding relationships between people and furniture for three different housing forms: 1) ordinary housing, 2) senior housing and 3) nursing homes. The results show that there is great variety in what old people express regarding furniture and reveal a diversity of interests, needs and wishes. In the light of these results, it is unreasonable to reduce old people to a homogeneous group or attempt to specify their needs in advance. Despite this, the results reveal needs and wishes for furniture that provide comfort, pleasure and independence and that contribute to desired experiences of dignity, meaningfulness and freedom. The results are presented in a model explaining how furniture may be attributed significance by older people. The model, which consists of four categories, 1) fit usage, 2) fit human body, 3) suit the individual and 4) fit physical environment, is proposed for use with other product types or services and also for people in other stages of their lives. In the results, old people are seen to be active and reflective users who are capable of identifying their needs as well as specifying and expressing their demands. The needs expressed by old people themselves differ from existing recommendations regarding furniture intended for old people. The latter are based primarily on the effects of physiological changes old people have undergone, whereas the results of this thesis indicate the need for products which provide support also for psychological and social changes and which correspond to a desired identity, i.e. that of an active, independent and self-determinant individual. The conclusion is that designers ought to be closely involved in researching the needs and wishes of old people and that they ought to embrace a holistic view on people and their diverse needs. This thesis recommends that future works in industrial and market oriented contexts utilize the knowledge generated in this thesis, involve users in iterative design processes, and create totally new or improved furniture solutions desirable and usable by people for as long period of their lives as possible

Evaluating Mission-Critical Self-Adaptive Software Systems: A Testing-Based Approach

Self-adaptive software is a closed-loop system that tries to manage, direct, or regulate its own behavior dynamically. Such a system aims at providing an automated and systematic approach to handling the increasing complexity of operation management. Mission-critical systems (e.g., e-business and telecommunication systems) are usually large, complex, and distributed. These systems must preserve their Quality of Service (QoS) at runtime under highly dynamic and non-deterministic conditions; therefore, they are suitable candidates for being equipped with self-adaptive capabilities. Although significant efforts have been devoted to modeling, designing, developing and deploying self-adaptive software since a decade ago, there is still a lack of well-established concrete processes for evaluating such systems. This dissertation proposes a systematic evaluation process for mission-critical self-adaptive software systems. The process is a well-defined testing approach that needs a post-mortem analysis, takes the quantified QoS requirements as inputs, and comprises two main phases: i) conducting system-level testing, and ii) evaluating QoS requirements satisfaction. The process uses Service Level Agreements (SLAs) as quantified QoS requirements, and consequently as the adaptation requirements of mission-critical systems. Adaptation requirements are specific types of requirements used to engineer self-adaptive software. Moreover, for the first phase, the dissertation discusses the uniqueness and necessity of conducting system-level load and stress testing on a self-adaptive software system, for collecting runtime QoS data. In the second phase, the process makes use of utility functions to generate a single value indicating the QoS satisfaction of the evaluated system. The dissertation mainly focuses on evaluating the performance, availability and reliability characteristics of QoS. An open source service-oriented Voice over IP (VoIP) application was selected as a case study. The VoIP application was transformed into a self-adaptive software system with various types of adaptation mechanisms. A set of empirical experiments was performed on the developed self-adaptive VoIP application, and the proposed process was adopted for evaluating the effectiveness of different adaptation mechanisms. To this end, the dissertation defines a sample SLA for the VoIP application, presents a report on the load and stress testing performed on the self-adaptive VoIP application, and presents a set of utility functions for evaluation. The experiments illustrate the validity, reliability, flexibility, and cost of the proposed evaluation process. In sum, this dissertation introduces a novel evaluation process for mission-critical self-adaptive software systems, and shows that the proposed process can help researchers to systematically evaluate their self-adaptive systems

Management: A bibliography for NASA managers

This bibliography lists 706 reports, articles, and other documents introduced into the NASA scientific and technical information system in 1984. Entries, which include abstracts, are arranged in the following categories: human factors and personnel issues; management theory and techniques; industrial management and manufacturing; robotics and expert systems; computers and information management; research and development; economics, costs, and markets; logistics and operations management; reliability and quality control; and legality, legislation, and policy. Subject, personal author, corporate source, contract number, report number, and accession number indexes are included

Exploring a best practice approach to operability and maintainability of low carbon buildings in the UK

Growth in technological advancement was to humanity a mixed blessing. While it provided comfort and improved quality of life, it also increased the demand for energy to drive them. This increase in energy usage, particularly from fossil fuel sources is widely understood to be responsible for the critical environmental problems in the world (Climate Change). Mitigating and adapting to this anthropogenic induced consequence created the need for varying innovative and new low carbon and renewable technologies which are gradually replacing the traditional high fossil fuel driven systems in buildings. Presently in the UK, every new building is expected to be low carbon and energy efficient; operated in such a manner as to use no more fuel and power than is reasonable in the circumstances. However, it is widely believed that construction underperforms in terms of capacity to deliver value. Clients and end-users of these buildings appear not to be getting long term value for their investments. Much attention has also not been given to how these new and innovative technologies can be operated and maintained long into the future. Recent researches also underpin the fact that the wide information gap existing between designers and building end-users is one of the factors responsible for the underperformance. This research therefore sought to explore a best practice approach that could bridge this information gap, and ensure that low carbon buildings are efficiently operated and maintained long into the future, particularly as the UK built environment moves closer to its zero carbon targets of 2016 and 2019. The research methodology involved triangulation (a mixed-method research approach), thus maximising the chances of benefiting from the strength of each of qualitative and quantitative methods. Interviews, surveys and case studies were employed. Post occupancy evaluation method was also used for the key case study. Findings indicate that there is a need for change in the way low carbon buildings are delivered to the end-users; that a properly prepared operation and maintenance (O&M) manual is indispensable in the effective and efficient operation and maintenance of low carbon buildings, and that it will be good practice to bring in the O&M team early to the design process. The study also suggested that designers be required to prove ‘life-cycle operability and maintainability’ of their designs before they are constructed. To ensure this desired cultural and process change in project delivery, a Maintainability and Operability Integrated (OMI) Design and Construction Process Model is proposed. The model was developed using the proposed RIBA 2013 revised Outline Plan of Work and drawing lessons from the New Product Development (NPD) process used by the manufacturing sector and other construction industry models. A validation test was conducted by means of a focus group, populated by top management officials of the University of Nottingham Estates Office, which has been actively involved in the procurement and management of myriads of low carbon buildings. Feedbacks from the validation test indicate that the proposed OMI Process Model was a well thought out idea which is practicable and capable of addressing the shortfall within the existing processes to deal with the O&M issues raised by the use of new and innovative low carbon technologies

Managing innovations in engineering industries

It has been shown in this thesis why innovations are regarded as the lifeline of engineering industries. Continuous flow of novel ideas is the source of innovations but the encouragement, creation and nurturing of such ideas requires many distinct managerial attributes. Hence, management of innovations is complex but an important area of study which is not amenable to standard analyses due to its multidisciplinary nature and dependence on a large number of intangible variables. It has been shown that proper management of innovations would involve at least three distinct but closely linked activities, namely: (a) managing people, in particular the innovators, as well as inspiring others to become innovators; (b) managing the environment so that it is conducive to innovations; and (c) managing innovative processes in order to ensure that innovations are properly nurtured, well targeted and economically implemented within clearly defined time and budgetary constraints. The thesis has been divided into eight chapters; an outline of the chapters is given below. Chapter 1 is an introduction to the subject of managing innovations in engineering industries. It sets the scene for carrying out research in this field, identifies the problems to be tackled and makes a clear statement of the aims. Chapter 2 offers a critical review of the published works relevant to the field of research covered in this thesis. The purpose of this study was to understand the state of the art approach to: (a) creating and maintaining the innovative environment; (b) inspiring and leading engineers to come up with innovative solutions for engineering problems; (c) managing the innovative processes for better efficiency. Finally, in view of the comprehensive review of the relevant published literature, this chapter justifies the aims of this research. Chapter 3 describes research methodology i. e. the procedure for conducting this programme of research. The purpose of this study was to ensure that the research programme was conducted in accordance with the scientific method as closely as practicable. For sake of clarity, chapter 4 first draws distinction between inventions, innovations and engineering design and later identifies a large number of intangible factors that influence the three principal components, i. e. innovative environment, innovators and the innovation process. It is suggested that the innovativeness of engineering companies depends on these three principal components. Hence, innovativeness may be assessed by determining the influence of each on the principal components with the help of suitable computational techniques. Two computer applications have been developed to: (a) evaluate the innovativeness of engineering organisations; and (b) analyse the risks embedded in either accepting innovative ideas or implementing innovative projects. These applications are based on questionnaires and may serve as computer aided management (CAM) tools for dealing with the multidimensional problem of managing innovations speedily and efficiently. Chapter 5 analyses the influence of factors identified in chapter 4 and uses the two aforementioned applications to survey the innovativeness of four engineering organisations for their innovativeness and evaluate two projects for the risks surrounding them. These assessments were carried in the form of six case studies. Chapter 6 and Chapter 7 present the results of the six case studies and a focused discussion of the results and other observations made during the course of this research. Chapter 8 draws conclusion from this research and proposes further work that may be carried out in order to study yet unknown factors, refine the questionnaires conduct further tests in different industrial environments to build confidence in the use of CAM Applications as tools for rapid response management of innovations in engineering industries