Opportunistic Software Systems Development: Making Systems from What's Available

Despite all the difficulties encountered in each incarnation of software reuse, we persist along the path of trying to figure out how we're going to create systems that meet the ever-increasing demand for capability and, with it, complexity and sheer size. Opportunistic software systems development is a reality today and for the foreseeable future, as the five articles in IEEE Software 's November/December 2008 special issue on OSSD demonstrate. This special issue aims to gather together insights into the viability, or perhaps the inevitability, of OSSD and to bring forward the most effective practices known today. Another goal is to point the way to what needs to be done to make OSSD more accessible to all practitioners. The editors hope to help the software community realize the importance of this new trend and the many aspects of it that have yet to be conquered.     

A cumulative score quality control scheme

Ncube and Woodall (1984) developed combined Shewhart­cumulative score (cuscore) quality control procedures for detecting shifts in the process mean of continuous production processes. These procedures only considered the past history of the scores but not that of the values of the quality characteristic, the sample mean. The proposed scheme takes into consideration the past history of the values of the sample mean quality characteristic and the past history of the scores. It will be shown, by average run length comparisons, that the proposed scheme performs significantly better than the standard cuscore procedures, the Shewhart procedures and cusum procedures for shifts in the process mean considered     

Impacts of HIV / AIDS on food consumption and wild food use in rural South Africa

HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.     

Exploring how to use scenarios to discover requirements

This paper investigates the effectiveness of different uses of scenarios on requirements discovery using results from requirements processes in two projects. The first specified requirements on a new aircraft management system at a regional UK airport to reduce its environmental impact. The second specified new work-based learning tools to be adopted by a consortium of organizations. In both projects scenarios were walked through both in facilitated workshops and in the stakeholders’ workplaces using different forms of a scenario tool. In the second project, scenarios were also walked through with a software prototype and creativity prompts. Results revealed both qualitative and quantitative differences in discovered requirements that have potential implications for models of scenario-based requirements discovery and the design of scenario tools.     

Acquiring COTS software selection requirements

Commercial off the shelf software can save development time and money if you can find a package that meets your customer's needs. The authors propose a model for matching COTS product features with user requirements. To support requirements acquisition for selecting commercial off the shelf products, we propose a method we used recently for selecting a complex COTS software system that had to comply with over 130 customer requirements. The lessons we learned from that experience refined our design of PORE (procurement oriented requirements engineering), a template based method for requirements acquisition. We report 11 of these lessons, with particular focus on the typical problems that arose and solutions to avoid them in the future. These solutions, we believe, extend state of the art requirements acquisition techniques to the component based software engineering process     

The impact of climate variability on water and energy demand: the case of South African local governments

There is a growing need to understand how climate change impacts not only on people's livelihoods but also on the level and cost of local government infrastructure required to provide basic commodities such as water and energy. In South Africa, few studies have examined the impact of climate change on operations of local governments. This paper examines the impact of rainfall variability on municipalities’ water and energy demand. A non‐linear relationship between water and energy demand and rainfall variability was found. The results suggest that, by influencing the operations and budgets of local governments, climate change is a real threat to local governments. The local governments need to be proactively involved in the efforts to adapt to and mitigate climate change. This is particularly important in developing countries where the impact of climate change is more severe than in developed countries, yet adaptation and mitigation capabilities in these countries are weak.     

Raising the productivity of smallholder farms under semi-arid conditions by use of small doses of manure and nitrogen: a case of participatory research

Participatory on-farm trials were conducted for three seasons to assess the benefits of small rates of manure and nitrogen fertilizer on maize grain yield in semi-arid Tsholotsho, Zimbabwe. Two farmer resource groups conducted trials based on available amounts of manure, 3 t ha⁻¹ (low resource group) and 6 t ha⁻¹ (high resource group). Maize yields varied between 0.15 t ha⁻¹ and 4.28 t ha⁻¹ and both absolute yields and response to manure were strongly related to rainfall received across seasons (P < 0.001). The first two seasons were dry while the third season received above average rainfall. Maize yields within the seasons were strongly related to N applied (R ² = 0.77 in season 1, and R ² = 0.88 and 0.83 in season 3) and other beneficial effects of manure, possibly availability of cations and P. In the 2001–2002 season (total rainfall 478 mm), application of 3 and 6 t ha⁻¹ of manure in combination with N fertilizer increased grain yield by about 0.14 and 0.18 t ha⁻¹, respectively. The trend was similar for the high resource group in 2002–2003 although the season was very dry (334 mm). In 2003–2004, with good rainfall (672 mm), grain yields were high even for the control plots (average 1.2 and 2.7 t ha⁻¹). Maize yields due to manure applications at 3 and 6 t ha⁻¹ were 1.96 and 3.44 t ha⁻¹, respectively. Application of 8.5 kg N ha⁻¹ increased yields to 2.5 t ha⁻¹ with 3 t ha⁻¹ of manure, and to 4.28 t ha⁻¹ with 6 t ha⁻¹ of manure. In this area farmers do not traditionally use either manure or fertilizer on their crops, but they actively participated in this research during three consecutive seasons and were positive about using the outcomes of the research in future. The results showed that there is potential to improve livelihoods of smallholder farmers through the use of small rates of manure and N under semi-arid conditions.     

The impact of filter bed depth and solids loading using a multimedia filter

Design and operation of tertiary wastewater filters are not always well understood because of the inherent complexities of the wastewater matrix. Here, comparison of single, dual, triple and quadruple media (anthracite, flint, alumina and magnetite) filters were made to understand how the depth, media type and solids concentration influenced performance. The filter was improved by making the media deeper; however, the top 0.1 m of the filter retained the most solids. Additional layers of filter materials from single, dual, triple to quadruple improved the filter performance for the same depth of filter bed.     

Mechanical and Thermal Properties of Thermoset–Graphene Nanocomposites

Graphene has resulted in significant research effort to generate polymer nanocomposites with improved mechanical, thermal as electrical properties as compared to pure polymers. A large number of studies have been undertaken using different graphene derivatives, filler loadings, synthesis methods, and so on to obtain optimum filler dispersion as well as filler–matrix interactions, which are crucial for achieving significant enhancement in the properties, especially at low filler fraction. This review summarizes the mechanical and thermal properties of numerous studies carried out for the property enhancements of commercially relevant thermosetting materials such as epoxy, polyurethane, natural rubber, melamine formaldehyde, phenol formaldehyde, silicones, vinyl ester, cyanate ester, and unsaturated polyester resin.

     

Micro-dosing as a pathway to Africa’s Green Revolution: evidence from broad-scale on-farm trials

Next to drought, poor soil fertility is the single biggest cause of hunger in Africa. ICRISAT-Zimbabwe has been working for the past 10 years to encourage small-scale farmers to increase inorganic fertiliser use as the first step towards Africa’s own Green Revolution. The program of work is founded on promoting small quantities of inorganic nitrogen (N) fertiliser (micro-dosing) in drought-prone cropping regions. Results from initial on-farm trials showed that smallholder farmers could increase their yields by 30–100% through application of micro doses, as little as 10 kg Nitrogen ha⁻¹. The question remained whether these results could be replicated across much larger numbers of farmers. Wide scale testing of the micro-dosing (17 kg Nitrogen ha⁻¹) concept was initiated in 2003/2004, across multiple locations in southern Zimbabwe through relief and recovery programs. Each year more than 160,000 low resourced households received at least 25 kg of nitrogen fertiliser and a simple flyer in the vernacular explaining how to apply the fertiliser to a cereal crop. This distribution was accompanied by a series of simple paired plot demonstration with or without fertiliser, hosted by farmers selected by the community, where trainings were carried out and detailed labour and crop records were kept. Over a 3 year period more than 2,000 paired-plot trials were established and quality data collected from more than 1,200. In addition, experimentation to derive N response curves of maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R.Br.) in these environments under farmer management was conducted. The results consistently showed that micro-dosing (17 kg Nitrogen ha⁻¹) with nitrogen fertiliser can increase grain yields by 30–50% across a broad spectrum of soil, farmer management and seasonal climate conditions. In order for a household to make a profit, farmers needed to obtain between 4 and 7 kg of grain for every kg of N applied depending on season. In fact farmers commonly obtained 15–45 kg of grain per kg of N input. The result provides strong evidence that lack of N, rather than lack of rainfall, is the primary constraint to cereal crop yields and that micro-dosing has the potential for broad-scale impact on improving food security in these drought prone regions.