A requirements engineering framework for developing COTS GIS applications : a thesis presented in partial fulfilment of the requirements for the degree of Master of Information Science in Information Systems at Massey University

There has been an increase in recent years in the number of Geographic Information System (GIS) applications being developed for stakeholders using Commercial Off-The-Shelf (COTS) software. There are a lack of guidelines in both industry and the literature on how to acquire user requirements for the development of GIS applications in this COTS software environment. This study investigates process activities in order to build a framework to address these inadequacies. The construction of the framework incorporates requirements engineering and COTS software evaluation and selection process activities from the Information Systems (IS) area. The framework is used to explore three issues related to developing GIS applications and used to determine whether: 1) a life cycle model is used to guide the gathering and analysing of requirements when developing GIS applications, 2) standard IS requirements processes can be used for developing GIS solutions, and 3) standard IS COTS software acquisition processes can be used for developing GIS solutions. Case studies were used to analyse current practices in the GIS industry and to validate the usefulness of these activities in the framework. The results of this investigation suggest that RE practices associated with the COTS paradigm within the IS arena are suitable for developing GIS applications based on user requirements

Post-polypectomy surveillance colonoscopy: In whom and when?

Introduction Post-polypectomy surveillance by colonoscopy is recommended in national and international guidelines. While colonoscopy is the gold standard colorectal investigation, it carries a risk of adverse events as well as being inconvenient and often uncomfortable for the patient. It is established that population screening reduces mortality from colorectal cancer (CRC). The effect of post-polypectomy surveillance, however, is less clear. An increasing number of colonoscopies are being performed worldwide for both symptoms and screening. The adenoma detection rate at colonoscopy is also increasing with improved technology and training against the backdrop of an ageing population. As a result, an increasing number of individuals are entering post-polypectomy surveillance. Aims & Objectives The aim of the analysis was to evaluate the findings of post-polypectomy surveillance within the English Bowel Cancer Screening Programme (BCSP). This was done by assessing linked data from the BCSP database and the National Cancer Registration and Analysis Service (NCRAS). Objectives were: 1. To document surveillance pathways among the intermediate and high risk groups. 2. To determine the risk factors (adenoma and person-specific) at screening which predict the outcome of initial surveillance. 3. To determine the adenoma, advanced adenoma (AA) and CRC yield at initial surveillance of each colonoscopy surveillance cohort (and subcategories within each cohort) within the BCSP. Methods Data on individuals participating in the BCSP is entered prospectively onto the screening programme’s relational database, BCSS. BCSS was interrogated for individuals who had attended for post-polypectomy surveillance at any time from the start of the programme in 2006 until the end of 2016. In addition, linked data on CRCs diagnosed in this cohort were obtained from NCRAS. Two separate analyses were performed. The first focussed on the detection of any AA (size ≥10mm or ≥25% villous or high-grade dysplasia) at the first surveillance attended by an individual. A separate analysis was performed with a diagnosis of CRC as the primary outcome. Results Of individuals with high risk findings at baseline colonoscopy, 12.3% of those attending first surveillance were found to have AA, 48.0% non-advanced adenoma, 39.1% no adenoma, and 0.5% CRC. In the case of individuals with intermediate risk findings at baseline, of those attending first surveillance, 8.0% were found to have AA, 35.3% non-advanced adenoma, 56.1% no adenoma, and 0.4% CRC. In those categorised as intermediate risk based on the finding of a single adenoma (≥10mm) at baseline, 6.3% of those attending first surveillance were found to have AA and 0.3% CRC. The most significant factor increasing the risk of AA at first surveillance was a higher total number of adenomas at baseline colonoscopy. Conclusions The rates of AA and CRC at first surveillance are relatively low and were found to be higher in the high risk group compared to intermediate risk. Those individuals categorised as intermediate risk based on a single adenoma (≥10mm) at baseline, had a particularly low rate of AA and CRC at first surveillance. These findings support the hypothesis that the incidence of AA and CRC are low at post-polypectomy surveillance colonoscopy. The particularly low yield in the subgroup with a single adenoma at baseline suggests that surveillance is not be needed in this group and may not be necessary for the intermediate risk cohort as a whole

Tensions in relation: How peer support is experienced and received in a hepatitis C treatment intervention.

Peer support and involvement is recognised as a vital component of hepatitis C (HCV) treatment provision for marginalised populations, such as people who inject drugs (PWID). Developments in HCV treatments enable increased provision in community settings - expanding the possibilities for meaningful peer involvement in HCV treatment plans. To date, HCV peer support has generally been viewed as a positive intervention, with little critical reflection on the ways social structures, policies, health and drug services and social identity impact on how peer support is experienced and received. We report on the qualitative component of a UK-based intervention designed to increase HCV diagnosis and treatment in primary care and drug treatment settings. Data were collected between 2014 and 2016. Pre-intervention, a total of 35 PWID clients took part in nine in-depth interviews and four focus groups. In addition, 22 drug services and intervention providers took part in two focus groups and nine interviews. Post-intervention, one focus group and eight interviews were conducted with 13 PWID clients, and four focus groups and ten interviews were conducted with 26 drug services and intervention providers. Our data generation and thematic analysis focused on the peer education and buddy support component of the intervention. Participants had common expectations of the peer role (to 'just be there') and its occupants' attributes (empathy, trustworthy, etc.). However, in practice, peers faced constraints on realising these expectations. A 'recovery' dominated drug treatment ethos in the UK appeared to influence the selection of 'recovery champions' as peers for the intervention. This created tensions in relations with clients, particularly when risk-adverse discourses were internalised by the peers. Peers were poorly integrated and supported within the service, affecting opportunities to relate and build trust with clients. Thus, the scope for peer support to impact on the nature and extent of clients' testing and treatment for HCV was limited. The efficacy of peer involvement can be constrained by organisational structures and boundaries - especially regarding who is deemed to be 'a peer'. Peer programmes take time and care to implement and weave into wider recovery and harm reduction frameworks

Geodesics in Transitive Graphs

AbstractLetPbe a double ray in an infinite graphX, and letdanddPdenote the distance functions inXand inPrespectively. One callsPageodesicifd(x, y)=dP(x, y), for all verticesxandyinP. We give situations when every edge of a graph belongs to a geodesic or a half-geodesic. Furthermore, we show the existence of geodesics in infinite locally-finite transitive graphs with polynomial growth which are left invariant (set-wise) under “translating” automorphisms. As the main result, we show that an infinite, locally-finite, transitive, 1-ended graph with polynomial growth is planar if and only if the complement of every geodesic has exactly two infinite components

Embedding Digraphs on Orientable Surfaces

AbstractWe consider a notion of embedding digraphs on orientable surfaces, applicable to digraphs in which the indegree equals the outdegree for every vertex, i.e., Eulerian digraphs. This idea has been considered before in the context of compatible Euler tours or orthogonal A-trails by Andersen and by Bouchet. This prior work has mostly been limited to embeddings of Eulerian digraphs on predetermined surfaces and to digraphs with underlying graphs of maximum degree at most 4. In this paper, a foundation is laid for the study of all Eulerian digraph embeddings. Results are proved which are analogous to those fundamental to the theory of undirected graph embeddings, such as Duke's theorem [5], and an infinite family of digraphs which demonstrates that the genus range for an embeddable digraph can be any nonnegative integer given. We show that it is possible to have genus range equal to one, with arbitrarily large minimum genus, unlike in the undirected case. The difference between the minimum genera of a digraph and its underlying graph is considered, as is the difference between the maximum genera. We say that a digraph is upper-embeddable if it can be embedded with two or three regions and prove that every regular tournament is upper-embeddable

Analysis of organosilicone surfactants and their degradation products

In this work the analysis of the organosilicone surfactant Silwet L-77 and components thereof is described. The commercial product Silwet L-77 was demonstrated to comprise of ∼70% M₂D-C₃-O-(EO)ₙ-CH₃ (1),* ∼5% M₂D-C₃-O- (EO)ₙ-H (2) and ∼25% polar constituents. M₂D-C₃-O-(EO)ₙ-CH₃ oligomers were obtained by reversed-phase chromatography of Silwet L-77, and by synthetic procedures. Pure oligomers (n = 3, 6 and 9) were synthesised by reaction of the corresponding allyl-capped oligoethoxylate monomethyl ether M₂Dᴴ over a Pt catalyst. The allyl-capped ethoxylate monomethyl ethers were synthesised by reaction of allyl chloride with the corresponding ethoxylate monomethyl ethers (n = 3, 6 and 9). The longer chained oligoethylene glycols (n = 6 and 9) were prepared by etherification of smaller oligomers. Preparation of the organosilicone compounds M₂D-C₃-O-EO-COCH₃ and M₂D-C₃-OH were also investigated. Atmospheric pressure ionisation mass spectrometry (API/MS) is demonstrated to be a valid and informative method for the characterisation and quantitation of the organosilicone surfactants. Consistently reproducible quantitative results were achieved using an online HPLC separation system. Atmospheric pressure chemical ionisation (APcI) was used to enable high sample throughput, and the resulting HPLC/APcI/MS data obtained were improved both in reproducibility and sensitivity over conventional HPLC methods. The uptake mechanisms of agrochemical formulations and the role that surfactants play in this process are not well understood. The quantitative API/MS method developed and the use of synthesised Silwet L-77 components (1) enabled investigation of Silwet L-77 uptake into plant foliage (Chenopodium album). The influence of Silwet L-77 and constituents thereof on herbicide uptake was addressed, and dosage, spread, surfactant structure, solvation and solubility were implicated as important for uptake enhancement. Aspects of Silwet L-77 degradation were also addressed, for which API/MS methods were shown to be valid and informative. The well-established instability of Silwet L-77 to acid and alkaline conditions was characterised in more detail, with products, mechanisms and relative rates presented. Certain limitations of the API/MS method (i.e. product overlap, analyte suppression) required the use of additional methods to supplement the results obtained (LC/MS, GC/MS and NMR). The range of products formed in the degradation of Silwet L-77 were numerous as a result of the ability of the siloxane moiety to rearrange into a variety of lengths and structures, and compounded by the large number of components comprising the Silwet L-77 formulation. Unequivocal assignment of degradation product structure was thus complicated. Mass recovery following degradation was reduced in all experiments indicating the loss of volatile siloxane compounds. This was confirmed by headspace analysis. An increase in overall water-solubility for the degradation products over the parent surfactant was also observed. Rates and products appeared to be dependent on the conditions used, and were especially influenced by the solution pH. The use of fourier transform ion cyclotron resonance mass spectrometry (FTICR/MS) enabled the tentative assignment of four major products in the water-soluble fraction of degraded Silwet L-77. These were CH₃O(EO)ₙH (20), [1-SiCH₃+H] (21), cyclic tetramer [28; R¹, R², R³, R⁴ = C₃-O-(EO)ₙ-CH₃] and linear dimer [24; R¹, R² = TMS; R³, R⁴ = (EO)ₙ-CH₃]. Analysis of the degradation of purified M₂D-C₃-O-(EO)ₙ-Me (ave. n ∼7.5) samples by electrospray mass spectrometry (ESI/MS), FTICR/MS and HPLC/ESI/MS indicated CH₃O(EO)ₙH (20), [1-SiCH₃+H] (21) and [1- 2SiCH₃+2H] (22) as common degradation products. The linear dimer 24, [R¹ = H, R² = TMS; R³, R⁴ = (EO)ₙ-CH₃] was also indicated. The results also demonstrated that the HO(EO)ₙH, M₂D-C₃-O-(EO)n-H (2) and (Mᴿ)₂D-O-(EO)ₙ-CH₂CH= CH₂ (9, 10, 11; R = H or CH₃) compounds observed in the Silwet L-77 degradation mixture were synthetic by-products rather than degradation products. The degradation of single M₂D-C₃-O-(EO)ₙ-R oligomers confirmed the CH₃O(EO)ₙH (20), [1-SiCH₃+H] (21) and [1-2SiCH₃+2H] (22) as degradation products, and also indicated a range of linear and cyclic products both with and without the EO chains and terminal TMS groups intact. In general, the more silylated analogues of a structural series partitioned preferentially into the heptane-soluble fraction, and higher EO content derivatives were more commonly observed in the water-soluble fraction. Typically the products formed followed that for expected silanol stabilities, with longer EO chain products more stable as low condensation polymers and silanols, and short EO chains more commonly observed in cyclic products. The GC/MS analysis of the heptane-soluble fraction of acid-degraded Silwet L-77 enabled the tentative assignment of the cyclic trimer, 27 [R¹, R², R³ = -C₃- OH] product. ¹H and ¹³C NMR data also indicated this structure. ¹H NMR of the water-soluble fraction showed proton integration values indicative of the [1- 2SiCH₃+2H] (22) structure. After 2 years, the terminal Mᴿ groups were no longer detectable and extensive condensation had occurred, as determined by ²⁹Si NMR. The results demonstrated the rapid degradation of Silwet L-77 and derivatives thereof under extremes of pH and the highly complex nature of the products which are formed. API/MS was a valid and informative method for the study of the products formed, especially the high resolution FTICR/MS technique. Investigation into the stability of Silwet L-77 solutions on typical soil substrates indicated that there is little chance of surfactant persistence in aqueous soil environments. Reduced recovery was considered to be a result of degradation and/or strong sorption processes. Losses were most significant on substrates exhibiting extreme supernatant pH values (montmorillonite, halloysite). Reduced recoveries were also higher with higher clay content. Studies on clays indicated that supernatant pH, potential for intercalation and surface charges are important factors in the recovery process. In the case of the montmorillonite and illite clays, recoveries may be more significantly affected by sorption, as strong surfactant substrate interactions were observed immediately following application. The results obtained support previous observations that Silwet L-77 is relatively benign in the natural environment. Primary degradation is rapid and ultimate degradation to naturally occurring compounds i.e. CO₂, H₂O and Si(OH)₄, can be predicted according to the structures of the observed intermediates. However covalent bonding of degradation products to substrates was observed which may result in some environmental accumulation. In land applications this could cause aggregation of silicate minerals and/or affect the sorption capacity of the soil. An increase in sorption capacity could have positive or detrimental effects. The concentrations required for biotoxicity for Silwet L-77 and degradation products thereof are in large excess of any likely input by agricultural practices. Phytotoxicity was also low and this appeared to be a result of the dilution effects caused by high spreading. *M₂D- [Si(CH₃)₃-O]₂-Si(CH₃)- ; C₃ = (CH₂)₃; EO = CG₂CH₂