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Acute rashes are a common medical problem in primary and secondary care. Approximately 5% of both paediatric and adult presentations to emergency departments are because of a rash illness. Fever, rash, headache and malaise are common features of many viral infections. Typically, rashes of infective aetiology can be divided into four categories: maculopapular, vesicular, papular/purpuric and other infectious immune-associated erythematous rash presentations. Although the early morphological features of viral rashes can appear similar, they differ in their character, evolution and accompanying associated clinical features. The serious but uncommon adverse complications of infections inducing viral exanthems increase their clinical and public health importance. Further diagnostic support through testing can be done by swabbing lesions using polymerase chain reaction (PCR) methods for direct virus genome detection in the early stages, or by viral serology to detect specific immunoglobulin (Ig) G and IgM responses in the later stages of infection. The use of these syndromic descriptions in the identification of virus illnesses recognizes the similarities between these diseases but helps to limit the differential diagnostic range of viral infections causing an erythematous rash and focus diagnostic testing and management interventions (where available) more appropriately.

Cytomegalovirus (CMV) shedding in genital and oral secretions during pregnancy is associated with adverse outcomes. Sample collection methods between studies are not uniform and currently there are limited data on the impact of biological fluids, swab types and storage durations on the detection of CMV DNA.To evaluate the absorption efficiency and CMV DNA recovery of various commercially available swabs in vaginal and saliva fluids.The absorption volume of different swab types was evaluated. The recovery of CMV DNA over time from vaginal and saliva fluids, and vaginal and saliva swabs, was evaluated by PCR measurements of samples spiked with CMV standard.Absorption efficiency of swabs varied significantly. The duration of storage did not affect CMV DNA recovery from vaginal fluid or swabs, but did significantly affect CMV DNA recovery from neat saliva fluid and saliva swabs stored dry or in viral transport media (VTM). Flocked swab/eNAT media recovered the highest amount of CMV DNA from both fluids. In saliva, flocked swab/eNAT media and polyester swab/cobas media demonstrated a higher CMV DNA recovery than foam swab/VTM. 25% of dry saliva foam swabs were falsely negative for CMV DNA.Recovery of CMV DNA is dependent on sample type and swab type used. Flocked swab/eNAT media and polyester swab/cobas media appear acceptable, though flocked swab/eNAT media was superior demonstrating the best recovery of CMV DNA. For saliva, foam swabs stored dry or in VTM was shown to be inferior to flocked or polyester swabs.

Summary Background During high-incidence influenza seasons, a robust infection prevention and control policy is imperative to reduce nosocomial transmission of influenza. Aim To assess the impact of influenza point-of-care testing (POCT) in an emergency department (ED) and patient cohorting on an influenza ward on infection prevention and control and clinical outcomes. Methods Influenza POCT was operational in the study ED from 21st January 2018 and patient cohorting was operational on an influenza ward from 25th January 2018. A retrospective ‘before–after’ analysis was performed with pre-intervention defined as 1st November 2017 to 20th January 2018 and post-intervention defined as 21st January 2018 to 30th April 2018. The primary outcome was the rate of hospital-acquired influenza. Secondary outcomes included antiviral prescription and length of stay. The length of time that inpatients remained influenza-positive was estimated by polymerase chain reaction (PCR). Findings There were 654 inpatients with confirmed influenza during the 2017/18 influenza season: 223 pre- and 431 post-intervention. Post-intervention, there were fewer cases of hospital-acquired influenza per day (0.66 vs 0.95, P Conclusion Influenza POCT in an ED and patient cohorting on an influenza ward were associated with reduced nosocomial transmission of influenza and improved patient flow. A policy of retesting immunocompetent patients five days post-diagnosis could allow half of these patients to come out of respiratory isolation earlier.

Summary The cobas Liat influenza A/B and respiratory syncytial virus (RSV) assay (Liat) was used in the adult emergency department of a large London hospital from 21st January 2018 to 14th April 2018. Influenza was detected in 308 of 1027 (30%) samples tested; influenza A in 157 (15.3%), influenza B in 149 (14.5%) and RSV in 28 (2.7%). When compared against Fast Track Diagnostics Respiratory Pathogens 21 multiplex polymerase chain reaction and Cepheid Xpert Xpress Flu/RSV assay, Liat performance for the detection of influenza A or B was: sensitivity 85% [95% confidence interval (CI) 76–92)], specificity 98% (95% CI 97–99), negative predictive value 94% (95% CI 92–96) and positive predictive value 95% (95% CI 91–97).

Purpose. The analytical performance of the cobas 6800 HIV-1, HBV and HCV assays was verified and evaluated to the COBAS Ampliprep/COBAS TaqMan assays. Methodology. The precision, limit of detection (LoD), limit of quantification (LoQ) and linearity were verified using pooled residual clinical samples. The analytical specificity was verified with negative plasma. HIV-1 analytical reactivity was verified with WHO reference preparations. Accuracy was verified using EQA plasma panels. Evaluation of the equipment was performed using prospectively collected clinical whole blood samples. Results. Excellent precision was demonstrated using both testing protocols (coefficient of variation ≤15 %). The LoDs using the 500 and 200 µl protocols were 20 and 50 cp ml−1 for HIV-1, 10 and 20 IU ml−1 for HBV and 15 and 40 IU ml−1 for HCV, respectively. The LoQs were 40 and 100 cp ml−1 for HIV-1, 20 and 25 IU ml−1 for HBV and 30 and 80 IU ml−1 for HCV, respectively. Assays demonstrated good linearity (R2 ≥0.96). The analytical specificity of the assays was 100 %. There was excellent agreement between the cobas 6800 and CAP/CTM assays (kappa>0.94). The sensitivity, specificity, positive predictive value and negative predictive value for each of the assays were ≥99 %. The cobas HIV-1 and HCV mean quantifications were 0.03 log10 cp ml−1 and 0.17 log10 IU ml−1 higher than the CAP/CTM. The cobas HBV mean quantification was 0.17 log10 IU ml−1 lower than the CAP/CTM. Subtype/genotype specific differences were not observed. Conclusion. Cobas 6800 equipment and assays demonstrated excellent performance and correlated well with CAP/CTM assay results.

Background Congenital cytomegalovirus (CMV) is the most common congenital infection globally, however information about CMV is not routinely included in antenatal education in the United Kingdom. This feasibility study aimed to gather the essential data needed to design and power a large randomised controlled trial (RCT) to investigate the efficacy of a digital intervention in reducing the risk of CMV acquisition in pregnancy. In order to do this, we carried out a single-centre RCT, which explored the knowledge, attitudes and risk reduction behaviours in women in the intervention and treatment as usual groups, pre- and post-intervention. Methods CMV seronegative women living with a child less than four years old, receiving antenatal care at a single UK tertiary centre, were randomised to the digital intervention or ‘treatment as usual’ groups. Participants completed questionnaires before the digital intervention and after and at 34 gestational weeks, and responses within groups and between groups were compared using tailored randomisation tests. CMV serology was tested in the first trimester and at the end of pregnancy. Results Of the 878 women screened, 865 samples were analysed with 43% (n = 372) being CMV seronegative and therefore eligible to take part in the RCT; of these, 103 (27.7%) women were enrolled and 87 (84%) of these completed the study. Most participants (n = 66; 64%) were unfamiliar with CMV at enrolment, however at 34 gestational weeks, women in the intervention group (n = 51) were more knowledgeable about CMV compared to the treatment as usual group (n = 52) and reported engaging in activities that may increase the risk of CMV transmission less frequently. The digital intervention was highly acceptable to pregnant women. Overall, four participants seroconverted over the course of the study: two from each study group. Conclusions A large multi-centre RCT investigating the efficacy of a CMV digital intervention is feasible in the United Kingdom; this study has generated essential data upon which to power such a study. This single-centre feasibility RCT demonstrates that a digital educational intervention is associated with increase in knowledge about CMV and can result in behaviour change which may reduce the risk of CMV acquisition in pregnancy. Trial registration Clinicaltrials.gov, NCT03511274, Registered 27.04.18, http://www.Clinicaltrials.gov

The analytical performance of the cobas 6800 HIV-1, HBV and HCV assays was verified and evaluated to the COBAS Ampliprep/COBAS TaqMan assays.The precision, limit of detection (LoD), limit of quantification (LoQ) and linearity were verified using pooled residual clinical samples. The analytical specificity was verified with negative plasma. HIV-1 analytical reactivity was verified with WHO reference preparations. Accuracy was verified using EQA plasma panels. Evaluation of the equipment was performed using prospectively collected clinical whole blood samples.Excellent precision was demonstrated using both testing protocols (coefficient of variation ≤15 %). The LoDs using the 500 and 200 µl protocols were 20 and 50 cp mlCobas 6800 equipment and assays demonstrated excellent performance and correlated well with CAP/CTM assay results.

Background The widespread global access to antiretroviral drugs has led to considerable reductions in morbidity and mortality but, unfortunately, the risk of virologic failure increases with the emergence, and potential transmission, of drug resistant viruses. Detecting and quantifying HIV-1 drug resistance has therefore become the standard of care when designing new antiretroviral regimens. The sensitivity of Sanger sequencing-based HIV-1 genotypic assays is limited by its inability to identify minority members of the quasispecies, i.e., it only detects variants present above ~ 20% of the viral population, thus, failing to detect minority variants below this threshold. It is clear that deep sequencing-based HIV-1 genotyping assays are an important step change towards accurately monitoring HIV-infected individuals. Methods We implemented and verified a clinically validated HIV-1 genotyping assay based on deep sequencing (DEEPGEN™) in two clinical laboratories in the United Kingdom: St. George’s University Hospitals Healthcare NHS Foundation Trust (London) and at NHS Lothian (Edinburgh), to characterize minority HIV-1 variants in 109 plasma samples from ART-naïve or -experienced individuals. Results Although subtype B HIV-1 strains were highly prevalent (44%, 48/109), most individuals were infected with non-B subtype viruses (i.e., A1, A2, C, D, F1, G, CRF02_AG, and CRF01_AE). DEEPGEN™ was able to accurately detect drug resistance-associated mutations not identified using standard Sanger sequencing-based tests, which correlated significantly with patient’s antiretroviral treatment histories. A higher proportion of minority PI-, NRTI-, and NNRTI-resistance mutations was detected in NHS Lothian patients compared to individuals from St. George’s, mainly M46I/L and I50 V (associated with PIs), D67 N, K65R, L74I, M184 V/I, and K219Q (NRTIs), and L100I (NNRTIs). Interestingly, we observed an inverse correlation between intra-patient HIV-1 diversity and CD4+ T cell counts in the NHS Lothian patients. Conclusions This is the first study evaluating the transition, training, and implementation of DEEPGEN™ between three clinical laboratories in two different countries. More importantly, we were able to characterize the HIV-1 drug resistance profile (including minority variants), coreceptor tropism, subtyping, and intra-patient viral diversity in patients from the United Kingdom, providing a rigorous foundation for basing clinical decisions on highly sensitive and cost-effective deep sequencing-based HIV-1 genotyping assays in the country. Electronic supplementary material The online version of this article (10.1186/s12981-018-0206-y) contains supplementary material, which is available to authorized users.

Everything we are doing in R&D is to develop methods and a code for robust, accurate and efficient algorithms in a Parallel (MPI) Modular Object-Oriented code for Industry and Researchers.

Research and development of KIVA-hpFE for turbulent reactive and multiphase flow particularly as related to engine modeling program has relevance to National energy security and climate change. Climate change is a source problem, and energy national security is consumption of petroleum products problem. Accurately predicting engine processes leads to, lower greenhouse gas (GHG) emission, where engines in the transportation sector currently account for 26% of the U.S. GHG emissions. Less dependence on petroleum products leads to greater energy security. By Environmental Protection Agency standards, some vehicles are now reaching 42 to the 50 mpg mark. These are conventional gasoline engines. Continued investment and research into new technical innovations, the potential exists to save more than 4 million barrels of oil per day or approximately $200 to $400 million per day. This would be a significant decrease in emission and use of petroleum and a very large economic stimulus too! It is estimated with further advancements in combustion, the current emissions can be reduced up to 40%. Enabling better understanding of fuel injection and fuel-air mixing, thermodynamic combustion losses, and combustion/emission formation processes enhances our ability to help solve both problems. To provide adequate capability for accurately simulating these processes, minimizemore » time and labor for development of engine technology, are the goals of our KIVA development program.« less

Objectives To evaluate the performance of two enzyme immunoassays (EIA), Murex and ICE, and the Determine TP point-of-care test (POCT) in diagnosing treponemal infection (syphilis or yaws) in patients attending a large HIV clinic in Ghana; to determine the prevalence of treponemal co-infections; and to characterise demographic and clinical features of patients with infection. Methods Samples were tested with EIAs and rapid plasma reagin (RPR), then POCT and reference assays for Treponema pallidum to determine prevalence of active and past infection. Sensitivity and specificity of each assay were calculated and demographic and clinical characteristics of patients compared. Data were collected from case notes of patients retrospectively. Results Overall, 45/284 patient samples (14.8%, 95% CI, 11.1–19.4%) were Treponema pallidum particle agglutination (TPPA) positive, and of these, 27 (64.3%) were RPR positive and 4 (8.9%) were treponemal IgM positive. Both EIAs and Determine TP POCT showed high sensitivities and specificities for identifying infection although RPR was less reliable. Clinical features of syphilis or yaws were rarely identified in TPPA-positive patients suggesting most had previous or late latent infection. Treatment of various intercurrent infections using short courses of antibiotics active against T. pallidum was common in the clinic. Conclusions A high proportion of this HIV-infected cohort showed evidence of treponemal infection. Both EIAs as well as the POCT were practical and effective at diagnosing treponemal co-infection in this setting. RPR alone was unreliable at identifying active treponemal co-infection, however might be useful in some settings where treponemal-specific assays are unaffordable. Objectifs: Evaluer la performance de deux tests immunoenzymatiques (EIA), Murex et ICE et le test ‘Determine TP point-of-care (POCT)’ dans le diagnostic de l’infection treponemique (syphilis ou pian) chez les patients frequentant une grande clinique du VIH au Ghana; determiner la prevalence de la coinfection treponemique et caracteriser les caracteristiques demographiques et cliniques des patients infectes. Methodes: Les echantillons ont ete testes avec les tests EIA et le test rapide de la reagine plasmatique (RPR), puis avec le test POCT et le test de reference pour T. pallidum (TPPA), afin de determiner la prevalence de l’infection active et precedente. La sensibilite et la specificite de chaque test ont ete calculees et les caracteristiques demographiques et cliniques des patients ont ete comparees. Les donnees ont ete collectees retrospectivement a partir des notes de cas sur les patients. Resultats: Dans l’ensemble, 45/284 echantillons de patients (14.8%, IC95%: 11.1–19.4%) etaient positifs pour TPPA et de ceux-ci, 27 (64.3%) etaient RPR positifs et 4 (8.9%) etaient positifs pour les IgM treponemiques. Les tests EIA et POCT ont tous deux demontre des sensibilites et des specificites elevees pour identifier l’infection, alors que le test RPR etait moins fiable. Les caracteristiques cliniques de la syphilis ou pian ont rarement ete identifiees chez les patients positifs pour TPPA, suggerant que la plupart avaient des infections precedentes ou latentes tardives. Des traitements d’infections intercurrentes diverses utilisant des regimes d’antibiotiques de courte duree, actifs contre T. pallidumetait courants dans la clinique. Conclusions: Une forte proportion de cette cohorte infectee par le VIH a montre des signes d’infection treponemique. Les tests EIA ainsi que le test POCT etaient pratiques et efficaces pour diagnostiquer la coinfection treponemique dans ce contexte. Le test RPR seul n’etait pas fiable pour identifier les coinfections treponemiques actives, mais pourrait etre utile dans certains contextes ou des tests treponemiques specifiques sont inabordables. Objetivos: Evaluar el desempeno de dos inmunoensayos enzimaticos (IEE), Murex e ICE, y la prueba rapida in situ (POCT) Determine TP en el diagnostico de infeccion por treponema (sifilis o pian), en pacientes de una gran clinica para VIH en Ghana; determinar la prevalencia de coinfecciones con treponema; y determinar las caracteristicas demograficas y clinicas de los pacientes con infeccion. Metodos: Con las muestras se realizaron las pruebas de IEEs y la Prueba Rapida de Reagina (RPR), despues la POCT y pruebas de referencia para T. pallidum, con el fin de determinar la prevalencia de infecciones activas y pasadas. Se calcularon la sensibilidad y la especificidad de cada ensayo y se compararon las caracteristicas clinicas y demograficas de los pacientes. Los datos se recogieron de forma retrospectiva de las historias clinicas de los pacientes. Resultados: En general, 45/284 muestras de pacientes (14.8%, 95% IC, 11.1–19.4%) eran TP-PA positivas, y de estas 27 (64.3%) eran RPR positivas y 4 (8.9%) eran positivas para IgM de treponema. Tanto las IEEs como las POCT Determine TP mostraron una alta sensibilidad y especificidad para identificar la infeccion, aunque la RPR eran menos confiable. Las caracteristicas clinicas de la sifilis o el pian eran rara vez identificadas en pacientes TP-PA positivos, sugiriendo que la mayoria habian tenido infecciones previas o latente tardias. El tratamiento de varias infecciones concurrentes, utilizando tratamientos cortos de antibioticos activos frente a T. pallidum, era una practica comun en la clinica. Conclusiones: Una alta proporcion de esta cohorte infectada con VIH mostro evidencia de infeccion por treponema. Tanto las IEEs como las POCT eran practicas y efectivas en el diagnostico de una coinfeccion con treponema, aunque podria ser util en emplazamientos en los que las pruebas especificas para treponema son inasequibles.

Background A large outbreak of hepatitis B virus (HBV) infection in the UK occurred between 2001 and 2005 in Bristol, UK. Objectives To identify HBV strains circulating amongst risk groups in the HBV outbreak cohort. Study design Cross-sectional study of acute HBV outbreak cases in Bristol. Results HBV sequences from sera of 95 of the 237 cases (40%) were characterised. The majority of cases (77%) were found to carry an HBV variant belonging to genotype D, designated HBVBV. Eighty-eight percent (36/41) of sequences from injection drug users were HBVBV as were 70% (19/27) from those with heterosexual intercourse as the primary identified risk factor. Of 15 sequences characterised from cases of pre-outbreak acute or chronic hepatitis B residing in Bristol, 40% also carried HBVBV; the earliest was from a case identified in 1994. Conclusion The findings from this study link the spread of HBVBV from injecting drug users to the general population through heterosexual intercourse during the outbreak. The molecular sequencing of specimens from this outbreak reports the emergence of HBVBV, a HBV strain circulating in Bristol and South West England, as the cause of one of the largest outbreaks of acute hepatitis B in the UK.

Background Nucleic acid amplification tests are being increasingly used for the routine diagnosis of Neisseria gonorrhoeae (GC), although culture remains essential for monitoring antimicrobial resistance. The authors investigated how symptoms and infection site influenced test sensitivity. Methods This was a retrospective study at two centres of patients diagnosed as having GC by Aptima Combo 2 (AC2) confirmed with Aptima GC and/or culture. Results The study included 251 men (71%) and 105 women (29%). The sensitivity for AC2 and culture in the lower genital tract of men with symptoms was 99% (95% CI 95% to 100%) and 79% (95% CI 71% to 85%) and for asymptomatic men was 94% (95% CI 69% to 100%) and 29% (95% CI 11% to 56%), respectively. At the rectum, the sensitivity in symptomatic men was 91% (95% CI 57% to 100%) and 55% (95% CI 25% to 82%) and in asymptomatic men 75% (95% CI 47% to 92%) and 44% (95% CI 21% to 69%) for AC2 and culture, respectively. In symptomatic women, the sensitivity from the genital site was 100% (95% CI 95% to 100%) and 53% (95% CI 38% to 68%) and for asymptomatic women 100% (95% CI 87% to 100%) and 47% (95% CI 30% to 65%) for AC2 and culture, respectively. Conclusions The AC2 with AGC confirmation performs well at genital and extra-genital sites for detecting GC. Culture for GC using transport swabs performs poorly in asymptomatic men, symptomatic and asymptomatic women and at extra-genital sites. With the improved performance of nucleic acid amplification tests and the increase in GC antimicrobial resistance, research is needed into how best to optimise GC culture in settings where direct plating is not feasible.

Design patterns are typically defined imprecisely using natural language descriptions with graphical annotations. It is also common to describe patterns using a concrete design example with implementation details. Several approaches have been proposed to describe design patterns abstractly based on role concepts. However, the notion of role differs in each approach. The behavioral aspects of patterns are not addressed in the role-based approaches. This paper presents a rigorous approach to describe design patterns based on role concepts. Adopting metamodeling and formalism, our work defines an innovative framework where generic pattern concepts based on roles are precisely defined as a formal role metamodel using Object-Z. Individual patterns are specified using these generic role concepts in terms of pattern role models. Temporal behaviors of patterns are also specified using Object-Z and integrated in the pattern role models. Patterns described this way are abstract, separating pattern realization information from the pattern description. They are also precise providing a rigorous foundation for reasoning about pattern properties. This paper also formalizes the properties that must be captured in a class model when a design pattern is deployed. These properties are defined generically in terms of role bindings from a pattern role model to a class model. They provide a precise basis for checking the validity of pattern utilisation in designs. Our work is supported by tools. We have developed an initial role metamodel using an existing modeling framework, Eclipse Modeling Framework (EMF) and have transformed the metamodel to Object-Z using model transformation techniques. Complex constraints are added to the transformed Object-Z model. More importantly, we implement the role metamodel. Using this implementation, pattern authors can develop an initial pattern role model in the same modeling framework and convert the initial model to Object-Z using our transformation rules. The transformed Object-Z model is then enhanced with behavioral features of the pattern. This tool support significantly improves the practicability of applying formalism to design patterns.

Radiative transfer in participating media is modeled using a first-order spherical harmonics (P1), or its degenerate form, diffusion. The equations are discretized on an unstructured grid. The method uses a matrix-free algorithm employing an iterative solver from the Preconditioned Conjugate Gradient (PCG) solver package developed by Joubert and Carey [1]. The algorithm couples radiation transport and conduction, by casting them into a Picard iteration. Compared are solutions for two participating media problems indicating the method to be first-order accurate in time. Parallel scaling of the matrix-free method with use of in-situ preconditioners, symmetric successive overrelaxation (SSOR) and block Jacobi, are reported.

Statistical testing involves the testing of software by selecting test cases from a probability distribution that is intended to represent the software's operational usage. In this paper, we describe and evaluate a framework for statistical testing of software components that incorporates test case execution and output evaluation. An operational profile and a test oracle are essential for the statistical testing of software components because they are used for test case generation and output evaluation respectively. An operational profile is a set of input events and their associated probabilities of occurrence expected in actual operation. A test oracle is a mechanism that is used to check the results of test cases. We present four types of operational profiles and three types of test oracles, and empirically evaluate them using the framework by applying them to two software components. The results show that while simple operational profiles may be effective for some components, more sophisticated profiles are needed for others. For the components that we tested, the fault-detecting effectiveness of the test oracles was similar.

Infective diarrhoea is common among allogeneic stem cell transplant (SCT) recipients, frequently caused by viruses and may be difficult to differentiate from acute graft-versus-host disease (GVHD). Viral pathogens may directly or indirectly impact upon transplant-related mortality. Rotavirus is one of the most common causes of diarrhoea worldwide, but one of the least studied causes of diarrhoea post SCT. In this retrospective study we describe 21 cases of confirmed rotavirus infection in allogeneic SCT recipients. Most of these cases may occur in clusters during the winter and spring period. Symptoms of rotaviral infection were diarrhoea (95%), vomiting (62%), abdominal pain (38%), weight loss and loss of appetite in 38 and 29% of the cases, respectively. Possible extraintestinal manifestations of rotavirus infection were observed. The duration of the symptoms in this series ranged from 4 days to 4 months with median of 15 days. Patients with rotavirus infection were invariably lymphopenic and/or on immunosuppression for GVHD. Of the patients diagnosed with rotavirus, 86% required hospitalisation. In 57% of the cases, other viral pathogens were isolated near to the rotavirus infection period. Rotavirus infection is an important cause of prolonged diarrhoea post SCT, causing significant morbidity and frequently requiring hospitalisation.

This paper describes an ongoing collaboration between Boeing Australia Limited and the University of Queensland to develop and deliver an introductory course on software engineering. The aims of the course are to provide a common understanding of the nature of software engineering for all Boeing Australia's engineering staff, and to ensure they understand the practices used throughout the company. The course is designed so that it can be presented to people with varying backgrounds, such as recent software engineering graduates, systems engineers, quality assurance personnel, etc. The paper describes the structure and content of the course, and the evaluation techniques used to collect feedback from the participants and the corresponding results. The immediate feedback on the course indicates that it has been well received by the participants, but also indicates a need for more advanced courses in specific areas. The long-term feedback from participants is less positive, and the long-term feedback from the managers of the course participants indicates a need to expand on the coverage of the Boeing-specific processes and methods.

The refinement calculus is a well-established theory for deriving program code from specifications. Recent research has extended the theory to handle timing requirements, as well as functional ones, and we have developed an interactive programming tool based on these extensions. Through a number of case studies completed using the tool, this paper explains how the tool helps the programmer by supporting the many forms of variables needed in the theory. These include simple state variables as in the untimed calculus, trace variables that model the evolution of properties over time, auxiliary variables that exist only to support formal reasoning, subroutine parameters, and variables shared between parallel processes.

Software engineering educators need to provide environments where students learn about the size and complexity of modern software systems and the techniques available for managing these difficulties. Five universities used the personal software process to teach software engineering concepts in a variety of contexts.

The merit of automatic graph layout algorithms is typically judged by their computational eciency and the extent to which they conform to aesthetic criteria (for example, minimising the number of crossings, maximising orthogonality). Experiments investigating the worth of such algorithms from the point of view of human usability can take dierent forms, depending on whether the graph has meaning in the real world, the nature of the usability measurement, and the eect being investigated (algorithms or aesthetics). Previous studies have investigated performance on abstract graphs with respect to both aesthetics and algorithms, nding support for reducing the number of crossings and bends, and increasing the display of symmetry. This paper reports on preference experiments assessing the eect of individual aesthetics in the application domain of UML diagrams. Subjects’ preferences for one diagram over another were collected as quantitative data. Their stated reasons for their choice were collected as qualitative data. Analysis of this data enabled us to produce a priority listing of aesthetics for this domain. These UML preference results reveal a difference in aesthetic priority from those of previous domain-independent experiments.

Many automatic graph layout algorithms have been designed and implemented to display relational data in a graphical (usually node-arc) manner. The success of these algorithms is typically measured by their computational efficiency and the extent to which they conform to aesthetic criteria (for example, minimising the number of crossings, maximising symmetry). Little research has been performed on the usability aspects of such algorithms: do they produce graph drawings that make the embodied information easy to use and understandq Is the computational effort expended on conforming to the assumed aesthetic criteria justifiable with respect to better usabilityq This paper reports on usability studies that were performed to investigate the merit of automatic graph layout algorithms with respect to human use. The paper describes three ways in which this issue has been considered experimentally: first, investigating individual aesthetic criteria in simple, abstract graph structures; second, investigating the results of common automatic graph layout algorithms; and third, investigating individual aesthetic criteria and other relevant secondary notations in Unified Modeling Language class and collaboration diagrams. The results show that the use of only some aesthetics affect usability significantly, and that the semantic domain of the graph drawings affects which aesthetic criteria need to be emphasised.

Implementation of railway controller application logic is a highly safety-critical and time-consuming task carried out individually for each client and station by specialised signalling engineers, with corresponding high costs. M???a is a software development framework designed to create code generators for application logic for the client railway companies of Ansaldo STS that use the Microlok II controller to lower the cost and increase repeatability. This chapter describes the evolution of M???a from prototype to framework, and introduces the software engineering approaches of object-oriented meta-modelling and framework development along the way. It also presents known limitations and further application areas of the framework.

The mechanisation of the real numbers within theorem provers is of practical benefit for the verification of real-time systems. The real numbers provide a foundation within the theorem prover for classical mathematical analysis such as differentiation and integration. The approach we have taken makes extensive use of the theory interpretation facilities of the interactive theorem prover Ergo to maximise theory reuse and hence minimise theorem redundancy. The theory developed is compared with Harrison's HOL version.