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.     

Microbial Precipitation of Pb(II) with Wild Strains of Paraclostridium bifermentans and Klebsiella pneumoniae Isolated from an Industrially Obtained Microbial Consortium

The study focused on determining the microbial precipitation abilities of bacterial strains that were isolated from an industrially obtained Pb(II)-resistant microbial consortium. Previous research has demonstrated the effectiveness of the consortium on the bioprecipitation and adsorption of Pb(II) from solution. The bioremediation of Pb(II) using microbial precipitation provides an alternative option for Pb(II) removal from wastewater. Both strains, Klebsiella pneumoniae and Paraclostridium bifermentans, were successfully isolated from the consortium obtained from a battery recycling plant in South Africa. The experiments were conducted over both 30 h and 5 d, providing insight into the short- and long-term precipitation abilities of the bacteria. Various initial concentrations of Pb(II) were investigated, and it was found that P. bifermentans was able to remove 83.8% of Pb(II) from solution with an initial Pb(II) concentration of 80 mg L−1, while K. pneumoniae was able to remove 100% of Pb(II) with the same initial Pb(II) concentration after approximately 5 d. With the same initial Pb(II) concentration, P. bifermentans was able to remove 86.1% of Pb(II) from solution, and K. pneumoniae was able to remove 91.1% of Pb(II) from solution after 30 h. The identities of the precipitates obtained for each strain vary, with PbS and Pb0 being the main species precipitated by P. bifermentans and PbO with either PbCl or Pb3(PO4)2 precipitated by K. pneumoniae. Various factors were investigated in each experiment, such as metabolic activity, nitrate concentration, residual Pb(II) concentration, extracellular and intracellular Pb(II) concentration and the precipitate identity. These factors provide a greater understanding of the mechanisms utilised by the bacteria in the bioprecipitation and adsorption of Pb(II). These results can be used as a step towards applying the process on an industrial scale.     

Tetracarboxylic acid cobalt phthalocyanine SAM on gold: Potential applications as amperometric sensor for H2O2 and fabrication of glucose biosensor

This report describes the applications of cobalt tetracarboxylic acid phthalocyanine (CoTCAPc) self-assembled monolayer (SAM) immobilized onto a preformed 2-mercaptoethanol (Au-ME) SAM on gold surface (Au-ME-CoTCAPc SAM) as a potential amperometric sensor for the detection of hydrogen peroxide (H₂O₂) at neutral pH conditions. The Au-ME-CoTCAPc SAM sensor showed a very fast amperometric response time of approximately 1 s, good linearity at the studied concentration range of up to 5 μM with a coefficient R² = 0.993 and a detection limit of 0.4 μM oxidatively. Also reductively, the sensor exhibited a very fast amperometric response time (∼1 s), linearity up to 5 μM with a coefficient R² = 0.986 and a detection limit of 0.2 μM. The cobalt tetracarboxylic acid phthalocyanine self-assembled monolayer was then evaluated as a mediator for glucose oxidase (GOx)-based biosensor. The GOx (enzyme) was immobilized covalently onto Au-ME-CoTCAPc SAM using coupling agents: N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS), and the results demonstrated a good catalytic behavior. Kinetic parameters associated with the enzymatic and mediator reactions were estimated using electrochemical versions of Lineweaver-Burk and Hanes equation, and the stability of the sensor was tested. The biosensor (Au-ME-CoTCAPc-GOx SAM) electrode showed good sensitivity (7.5 nA/mM) with a good detection limit of 8.4 μM at 3σ, smaller Michaelis-Menten constant (4.8 mM from Hanes plot) and very fast response time of approximately 5 s.     

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.     

Surface chemistry and electrocatalytic behaviour of tetra-carboxy substituted iron, cobalt and manganese phthalocyanine monolayers on gold electrode

Surface chemistry and electrocatalytic properties of self-assembled monolayers of metal tetra-carboxylic acid phthalocyanine complexes with cobalt (Co), iron (Fe) and manganese (Mn) as central metal ions have been studied. These phthalocyanine molecules are immobilized on gold electrode via the coupling reaction between the ring substituents and pre-formed mercaptoethanol self-assembled monolayer (Au-ME SAM). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed chemisorption of mercaptoethanol via sulfur group on gold electrode and also coupling reaction between phthalocyanines and Au-ME SAM. Electrochemical parameters of the immobilized molecules show that these molecules are densely packed with a perpendicular orientation. The potential applications of the gold modified electrodes were investigated towards l-cysteine detection and the analysis at phthalocyanine SAMs. Cobalt and iron tetra-carboxylic acid phthalocyanine monolayers showed good oxidation peak for l-cysteine at potentials where metal oxidation (M^III/M^II) takes place and this metal oxidation mediates the catalytic oxidation of l-cysteine. Manganese tetra-carboxylic acid phthalocyanine monolayer also exhibited a good catalytic oxidation peak towards l-cysteine at potentials where Mn^IV/Mn^III redox peak occurs and this redox peak mediates l-cysteine oxidation. The analysis of cysteine at phthalocyanine monolayers displayed good analytical parameters with good detection limits of the orders of 10⁻⁷ mol L⁻¹ and good linearity for a studied concentration range up to 60 μmol L⁻¹.