Sources of Software Requirements Change from the Perspectives of Development and Maintenance

Changes to software requirements occur during initial development and subsequent to delivery, posing a risk to cost and quality while at the same time providing an opportunity to add value. Provision of a generic change source taxonomy will support requirements change risk visibility, and also facilitate richer recording of both pre- and post-delivery change data. In this paper we present a collaborative study to investigate and classify sources of requirements change, drawing comparison between those pertaining to software development and maintenance. We begin by combining evolution, maintenance and software lifecycle research to derive a definition of software maintenance, which provides the foundation for empirical context and comparison. Previously published change ‘causes’ pertaining to development are elicited from the literature, consolidated using expert knowledge and classified using card sorting. A second study incorporating causes of requirements change during software maintenance results in a taxonomy which accounts for the entire evolutionary progress of applications software. We conclude that the distinction between the terms maintenance and development is imprecise, and that changes to requirements in both scenarios arise due to a combination of factors contributing to requirements uncertainty and events that trigger change. The change trigger taxonomy constructs were initially validated using a small set of requirements change data, and deemed sufficient and practical as a means to collect common requirements change statistics across multiple projects.

List 229: Irish and English Dendrochronology

These results cover dating undertaken since the last published list of dated building from Ireland (Brown (2002)); one English church building is also included in the list. Thanks are due to the owners of the buildings and especially to everyone who assisted in taking of the samples: Phil Barrett, Sapphire Mussen, Charles Lyons, Jon Pilcher and Mike Baillie, Amanda Pedlow, Caimin O’Brien and Martin Timoney. Most of the descriptions of the buildings are taken from the National Inventory of Architectural Heritage http://www.buildingofi reland.ie/. The correlation values were generated by CROSS84 (Munro, 1984), which provides a signifi cance level for the date to be correct; *** (extremely signifi cant), ** (very signifi cant), * (signifi cant), nsm (not signifi cant). Estimated felling date ranges are based on the Belfast sapwood estimate of 32 ± 9 years. Date ranges have been calculated by adding and subtracting 9 years from the calculated estimated felling dates. Timbers from the following buildings could not be dated. Cork: St Finbarre’s Cathedral (W 675 715); Dublin: Christchurch Cathedral (O 152 341); Galway: Cloghan Castle (M 972 119); Kilkenny: Rothe House (S 506 563); Offaly: Boveen House (S 075 956); Waterford: Christchurch Cathedral (S 616 121). Generally only single oak samples were recovered from these structures. References: D.Brown, ‘Dendrochronological dating building from Ireland’, VA 33 (2002), 71–3; M. Munro, ‘An improved algorithm for crossdating tree-ring series’, Tree-Ring Bulletin 44 (1984), 17–27.

Resolving genetic functions within microbial populations: In situ analyses using rRNA and mRNA stable isotope probing coupled with single-cell raman-fluorescence in situ hybridization

Prokaryotes represent one-half of the living biomass on Earth, with the vast majority remaining elusive to culture and study within the laboratory. As a result, we lack a basic understanding of the functions that many species perform in the natural world. To address this issue, we developed complementary population and single-cell stable isotope (C-13)-linked analyses to determine microbial identity and function in situ. We demonstrated that the use of rRNA/mRNA stable isotope probing (SIP) recovered the key phylogenetic and functional RNAs. This was followed by single-cell physiological analyses of these populations to determine and quantify in situ functions within an aerobic naphthalene-degrading groundwater microbial community. Using these culture-independent approaches, we identified three prokaryote species capable of naphthalene biodegradation within the groundwater system: two taxa were isolated in the laboratory (Pseudomonas fluorescens and Pseudomonas putida), whereas the third eluded culture (an Acidovorax sp.). Using parallel population and single-cell stable isotope technologies, we were able to identify an unculturable Acidovorax sp. which played the key role in naphthalene biodegradation in situ, rather than the culturable naphthalene-biodegrading Pseudomonas sp. isolated from the same groundwater. The Pseudomonas isolates actively degraded naphthalene only at naphthalene concentrations higher than 30 mu M. This study demonstrated that unculturable microorganisms could play important roles in biodegradation in the ecosystem. It also showed that the combined RNA SIP-Raman-fluorescence in situ hybridization approach may be a significant tool in resolving ecology, functionality, and niche specialization within the unculturable fraction of organisms residing in the natural environment.

Development of a novel DNA microarray to detect bacterial pathogens in patients with chronic obstructive pulmonary disease (COPD)

A novel microarray was constructed with DNA PCR product probes targeting species specific functional genes of nine clinically significant respiratory pathogens, including the Gram-positive organisms (Streptococcus pneumoniae, Streptococcus pyogenes), the Gram-negative organisms (Chlamydia pneumoniae, Coxiella burnetii Haemophilus spp., Legionella pneumophila, Moraxella catarrhalis, and Pseudomonas aeruginosa), as well as the atypical bacterium, Mycoplasma pneumoniae. In a "proof-of-concept" evaluation of the developed microarray, the microarray was compared with real-time PCR from 14 sputum specimens from COPD patients. All of the samples positive for bacterial species in real-time PCR were also positive for the same bacterial species using the microarray. This study shows that a microarray using PCR probes is a potentially useful method to monitor the populations of bacteria in respiratory specimens and can be tailored to specific clinical needs such as respiratory infections of particular patient populations, including patients with cystic fibrosis and bronchiectasis. (C) 2010 Elsevier B.V. All rights reserved.

Isotopic composition of inorganic carbon as an indicator of benzoate degradation by Pseudomonas putida: temperature, growth rate and pH effects.

Degradation experiments of benzoate by Pseudomonas putida resulted in enzymatic carbon isotope fractionations. However, isotopic temperature effects between experiments at 20 and 30 °C were minor. Averages of the last three values of the CO2 isotopic composition (δ13CCO2(g)) were more negative than the initial benzoate δ13C value (−26.2‰ Vienna Pee Dee Belenite (VPDB)) by 3.8, 3.4 and 3.2‰ at 20, 25 and 30 °C, respectively. Although the maximum isotopic temperature difference found was only 0.6‰, more extreme temperature variations may cause larger isotope effects. In order to understand the isotope effects on the total inorganic carbon (TIC), a better measure is to calculate the proportions of the inorganic carbon species (CO2(g), CO2(aq) and HCO3−) and to determine their cumulative δ13CTIC. In all three experiments δ13CTIC was more positive than the initial isotopic composition of the benzoate at a pH of 7. This suggests an uptake of 12C in the biomass in order to match the carbon balance of these closed system experiments.

The effect of patient characteristics upon uptake of the influenza vaccination: a study comparing community based older adults in two healthcare systems

Background: Uptake of influenza vaccination represents a simple marker of proactive care of older people. However, many still do not receive the vaccine. To understand this challenge better, we investigated the relationship between patient characteristics (demographic, physical and psychological health, and health service use) and vaccination uptake in a sample of community-dwelling older people in two adjacent but differently structured healthcare systems (Northern Ireland (NI) and the Republic of Ireland (RoI)). Methods: 2,033 randomly selected community-dwelling older adults (65 years and older) were interviewed in their homes. Results: Rates of uptake were 78% in NI and 72% in RoI. Uptake was greater with older age (odds ratio (OR) 1.6, 95% confidence interval (CI) = 1.3-2.1, p

Stroke presentation and hospital management: comparison of neighbouring healthcare systems with differing health policies.

Background: Acute stroke care is shaped by healthcare policies. Differing policies in similar populations allow for assessment of policy impact on health and healthcare outcomes. Aims: To compare stroke presentation and hospital care in two adjacent healthcare systems with differing healthcare policies. Methods: Interviews and chart review of consecutive acute stroke admissions in Northern Ireland (n=103) and the Republic of Ireland (n=100). Results: Marked regional contrasts were evident for key aspects of hospital care. Northern Ireland performed significantly better on 15 of 16 quality of care (Sentinel Audit) items. Delivery on standards was significantly better in Northern Ireland for early assessment (Northern Ireland 72%; Republic of Ireland 54%, p