Availability Modeling of Modular Software

The attached file may be somewhat different from the published versionInternational audienceDependability evaluation is a basic component in the assessment of the quality of repairable systems. We develop here a general model specifically designed for software systems that allows the evaluation of different dependability metrics, in particular, of availability measures. The model is of the structural type, based on Markov process theory. In particular, it can be viewed as a attempt to overcome some limitations of the well-known Littlewood's reliability model for modular software. We give both the mathematical results necessary to the transient analysis of this general model and the algorithms that allow to evaluate it efficiently. More specifically, from the parameters describing : the evolution of the execution process when there is no failure, the failure processes together with the way they affect the execution, and the recovery process, we obtain the distribution function of the number of failures on a fixed mission period. In fact, we obtain dependability metrics which are much more informative than the usual ones given in a white-box approach. We briefly discuss the estimation procedures of the parameters of the model. From simple examples, we illustrate the interest in such a structural view and we explain how to take into account reliability growth of part of the software with the transformation approach developed by Laprie and al. Finally, the complete transient analysis of our model allows to discuss in our context the Poissonian approximation reported by Littlewood for its model

Requirements Prioritization Based on Benefit and Cost Prediction: An Agenda for Future Research

In early phases of the software cycle, requirements prioritization necessarily relies on the specified requirements and on predictions of benefit and cost of individual requirements. This paper presents results of a systematic review of literature, which investigates how existing methods approach the problem of requirements prioritization based on benefit and cost. From this review, it derives a set of under-researched issues which warrant future efforts and sketches an agenda for future research in this area

SOFTWARE RELIABILITY SIMULATION: PROCESS, APPROACHES AND METHODOLOGY

Reliability is probably the most crucial factor to put ones hand up for in any engineering process. Quantitatively, reliability gives a measure (quantity) of quality, and the quantity can be properly engineered using appropriate reliability engineering process. Software Reliability Modeling has been one of the much-attracted research domains in Software Reliability Engineering, to estimate the current state as well as predict the future state of the software system reliability. This paper aims to raise awareness about the usefulness and importance of simulation in support of software reliability modeling and engineering. Simulation can be applied in many critical and touchy areas and enables one to address issues before they these issues become problems. This paper brings to fore some key concepts in simulation-based software reliability modeling. This paper suggests that the software engineering community could exploit simulation to much greater advantage which include cutting down on software development costs, improving reliability, narrowing down the gestation period of software development, fore-seeing the software development process and the software product itself and so on

Engineering and water governance interactions in smallholder irrigation schemes for improved water management.

Masters Degree, University of KwaZulu-Natal, Durban.Smallholder Irrigation Schemes (SISs) in South Africa have reported below expectation performance, despite massive investments. A diagnosis of the SISs poor performance indicates prevalence of infrastructural deficiencies, as well as poor institutional setup. The government’s Irrigation Management Transfer (IMT) initiative compounds the problem. IMT placed irrigators in self-governance, which inadvertently made irrigators carry the burden of scheme Operation and Maintenance (O&M) costs. This study sought to investigate and evaluate how technical design principles i.e., technical aspect of irrigation design, interact with irrigation water governance for SISs in KwaZulu-Natal Province. The study hypothesized that the existing current water control infrastructure does relate to the water governance frameworks in the selected study sites. The study was carried out in Tugela Ferry Irrigation Scheme (TFIS) and Mooi-River Irrigation Scheme (MRIS). An infrastructure condition assessment was carried out followed by a root cause analysis. Questionnaires were then administered to relevant stakeholders to rate the degree of identified causal factors. Key informants ranked how water governance and infrastructure aspects are related. The data was processed using a fuzzy theory approach. Finally, structured questionnaires were administered to irrigators to establish how water governance impacted on water adequacy for crop production. A binary logit regression model was employed to process the data. Assessments revealed the poor condition of the infrastructure, such as deep cracks in canals and missing latches on hydrants. The study revealed that TFIS had a strong institutional setups according to the Closeness Coefficients( = 0.18), and clearly defined goals and objectives for the scheme operation. However, other governance aspects such as procedures ( = 0.17, = 0.16) were not strong. MRIS ( = 0.20) had a good standing on rules and regulations as compared to TFIS ( = 0.14). Eight water governance related statistically significant variables that influenced water adequacy were identified. The eight variables were irrigation scheme ( = 0.000), location of plot within the scheme ( = 0.008), training in water management ( = 0.012), satisfaction with irrigation schedule ( = 0.000), irrigation training ( = 0.085), farmer knowledge of governments aims in SIS ( = 0.012), availability of water licenses ( = 0.002), and water fees ( = 0.022). A descriptive analysis showed that 24% and 86% of the farmers in MRIS and TFIS respectively, had adequate water. The study concluded that the SISs lacked an O&M plan and the farmers were not willing to opt for collective action and iii cooperate in Water Users Association (WUAs) and Irrigation Management Committees (IMCs). Some of the water governance aspects were discordant with infrastructure characteristics and requirements, consequently, impacting on the water adequacy for the irrigators. Overall, the study proved the hypothesis that the water control infrastructure does not relate with the water governance framework. This study recommends that the stakeholders involved in SISs, i.e., government, extension workers, NGOs, should aid the irrigators in policy articulation. In addition, the WUA and IMCs should provide incentives to motivate farmers to actively participate in scheme O&M

DEFENSE ACQUISITION BEST PRACTICES: THE KNOWLEDGE-BASED APPROACH

Over the last decade, several response plans and methods have been established to reduce schedule and budget overruns in the Department of Defense’s (DOD) procurement programs. The Government Accountability Office (GAO) chose to revisit this issue in a recent study. They discovered that leveraging mature technology, having complete product designs, and having control over manufacturing processes were key to the successful development of new products. The GAO merged these principles into a single acquisition strategy known as the Knowledge-Based Approach (KBA). They assert that Major Defense Acquisition Programs (MDAP) that implement the KBA principles will have better program outcomes. The purpose of this research is to determine if MDAPs that meet the three basic KBA criteria outperform those that do not. MDAPs that adhered to KBA knowledge points were predicted to have lower percentages of schedule and budget overruns than those that did not. This thesis demonstrated a clear link between the KBA and program performance by using inferential testing to compare the KBA to the most recent MDAPs, thus validating the GAO’s approach, validating the research hypothesis, and promoting wider adoption of the KBA within the DOD’s acquisition community.Lieutenant, United States NavyApproved for public release. Distribution is unlimited

Virtual store atmosphere in internet retailing: Measuring virtual retail store layout effects on consumer buying behaviour

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The research presented in this dissertation is concerned with the effects of the "virtual store atmosphere" on consumer buying behaviour within the context of Internet retailing. More specifically, the focus of this research is to investigate whether the virtual store layout, as a major virtual store atmosphere determinant, affects consumer buying behaviour during shopping activity within a virtual grocery store over the Web. The present research is of a multidisciplinary nature and belongs to the field of Internet Retailing, in which there is not to date an exhaustive established theory available as the case is for conventional retailing. Therefore, the relevant literature covers the established theories in the areas of Marketing, Retailing and Consumer Behaviour along with current research in Internet retailing. Moreover, Human Computer Interaction (HCI) served as an important theoretical tool as far as Web site design principles and guidelines are concerned. The research hypotheses were mainly generated based on the conventional retail store layout literature review. They were tested through a laboratory experiment employing a causal research approach. To that end, a virtual retail laboratory store employing the three most common conventional retailing layouts (i.e., grid, freeform, and racetrack) was developed in three versions (i.e., one version per layout), following the concept and rules applied in each specific layout type. Therefore, the layout was the only manipulated variable (treatment), since all other potential influencing factors remained the same. The findings of the present study indicate that conventional retailing store layout theory is not applicable on its present form in the context of Internet retailing. Furthermore, the layout was found to affect consumer buying behaviour regarding "perceived usefulness towards searching for and buying shopping list products," "perceived ease of using the store," "perceived entertainment during shopping activity" and "time spent for shopping." However, it was found that the layout does not significantly affect "promotion effectiveness" and "impulse purchases." Based on the research findings, the "freegrid" layout (i.e., a new layout type) was introduced as an emerging layout for Internet retailing. The suggested layout contributes toward the Internet retailing theory development, as well as toward the provision of direct managerial implications. Finally, the present research provides several future research directions dealing with the virtual store atmosphere effects on consumer buying behaviour

Carbon Free Boston: Transportation Technical Report

Part of a series of reports that includes: Carbon Free Boston: Summary Report; Carbon Free Boston: Social Equity Report; Carbon Free Boston: Technical Summary; Carbon Free Boston: Buildings Technical Report; Carbon Free Boston: Waste Technical Report; Carbon Free Boston: Energy Technical Report; Carbon Free Boston: Offsets Technical ReportOVERVIEW: Transportation connects Boston’s workers, residents and tourists to their livelihoods, health care, education, recreation, culture, and other aspects of life quality. In cities, transit access is a critical factor determining upward mobility. Yet many urban transportation systems, including Boston’s, underserve some populations along one or more of those dimensions. Boston has the opportunity and means to expand mobility access to all residents, and at the same time reduce GHG emissions from transportation. This requires the transformation of the automobile-centric system that is fueled predominantly by gasoline and diesel fuel. The near elimination of fossil fuels—combined with more transit, walking, and biking—will curtail air pollution and crashes, and dramatically reduce the public health impact of transportation. The City embarks on this transition from a position of strength. Boston is consistently ranked as one of the most walkable and bikeable cities in the nation, and one in three commuters already take public transportation. There are three general strategies to reaching a carbon-neutral transportation system: • Shift trips out of automobiles to transit, biking, and walking;1 • Reduce automobile trips via land use planning that encourages denser development and affordable housing in transit-rich neighborhoods; • Shift most automobiles, trucks, buses, and trains to zero-GHG electricity. Even with Boston’s strong transit foundation, a carbon-neutral transportation system requires a wholesale change in Boston’s transportation culture. Success depends on the intelligent adoption of new technologies, influencing behavior with strong, equitable, and clearly articulated planning and investment, and effective collaboration with state and regional partners.Published versio

Unlocking markets to smallholders: Lessons from South Africa

This book assesses the institutional, technical and market constraints as well as opportunities for smallholders, notably, emerging farmers in disadvantaged areas such as the former homelands of South Africa. Emerging farmers are previously disadvantaged black people who started or will start their business with the support of special government programs. Public support programs have been developed as part of the Black Economic Empowerment strategy of the South African government. These programs aim to improve the performance of emerging farmers. This requires, first and foremost, upgrading the emerging farmers skills by providing access to knowledge about agricultural and entrepreneurial practices. To become or to remain good farmers they also need access to suitable agricultural land and sufficient water for irrigation and for feeding their cattle. Finally, for emerging farmers to be engaged in viable farming operations, various factors need to be in place such as marketing and service institutions to give credit for agricultural inputs and investments; input markets for farm machinery, farm implements, fertilizers and quality seeds; and accessible output markets for their end products. This book develops a policy framework and potential institutional responses to unlock the relevant markets for smallholders