Introduction to doctoral symposium

Submitted versio

Assessing climate model software quality: a defect density analysis of three models

A climate model is an executable theory of the climate; the model encapsulates climatological theories in software so that they can be simulated and their implications investigated. Thus, in order to trust a climate model, one must trust that the software it is built from is built correctly. Our study explores the nature of software quality in the context of climate modelling. We performed an analysis of defect reports and defect fixes in several versions of leading global climate models by collecting defect data from bug tracking systems and version control repository comments. We found that the climate models all have very low defect densities compared to well-known, similarly sized open-source projects. We discuss the implications of our findings for the assessment of climate model software trustworthiness

Hepatitis C: global epidemiology and strategies for control

It is estimated that globally there are approximately 100 million persons with serological evidence of current or past HCV infection, and that HCV causes about 700 000 deaths each year. The prevalence of infection is the highest in lower and middle income countries, in which a significant number of past infections were caused by iatrogenic transmission and sub-optimal injection safety. In contrast, in developed countries, infections are caused mainly by high-risk exposures and behaviours among specific populations, such as persons who inject drugs. Recently, new direct antiviral activity (DAA) oral drugs with high rates of cure over short duration, which are well tolerated, have made chronic hepatitis C a curable condition. The extraordinary clinical performance of DAAs and recent substantial price reductions and expansion in access in resource-limited settings has provided new impetus for potential control and elimination of hepatitis C as a public health threat. We review the global epidemiology of HCV and the opportunities for preventative and treatment interventions to achieve global control of HCV infection. We also summarize the key elements of the World Health Organization's first-ever global health sector strategy for addressing the viral hepatitis pandemic

Educationism and the irony of meritocracy: negative attitudes of higher educated people towards the less educated

Social psychology has studied ethnic, gender, age, national, and other social groups but has neglected education-based groups. This is surprising given the importance of education in predicting people’s life outcomes and social attitudes. We study whether and why people evaluate education-based in-groups and out-groups differently. In contrast with popular views of the higher educated as tolerant and morally enlightened, we find that higher educated participants show education-based intergroup bias: They hold more negative attitudes towards less educated people than towards highly educated people. This is true both on direct measures (Studies 1-2) and on more indirect measures (Studies 3-4). The less educated do not show such education-based intergroup bias. In Studies 5-7 we investigate attributions regarding a range of disadvantaged groups. Less educated people are seen as more responsible and blameworthy for their situation, as compared to poor people or working class people. This shows that the psychological consequences of social inequality are worse when they are framed in terms of education rather than income or occupation. Finally, meritocracy beliefs are related to higher ratings of responsibility and blameworthiness, indicating that the processes we study are related to ideological beliefs. The findings are discussed in light of the role that education plays in the legitimization of social inequality

Treatment exhaustion of highly active antiretroviral therapy (HAART) among individuals infected with HIV in the United Kingdon: multicentre cohort study

Objectives: To investigate whether there is evidence that an increasing proportion of HIV infected patients is starting to experience increases in viral load and decreases in CD4 cell count that are consistent with exhaustion of available treatment options. Design: Multicentre cohort study. Setting: Six large HIV treatment centres in southeast England. Participants: All individuals seen for care between 1 January 1996 and 31 December 2002. Main outcome measures: Exposure to individual antiretroviral drugs and drug classes, CD4 count, plasma HIV RNA burden. Results: Information is available on 16 593 individuals (13 378 (80.6%) male patients, 10 340 (62.3%) infected via homosexual or bisexual sex, 4426 (26.7%) infected via heterosexual sex, median age 34 years). Overall, 10 207 of the 16 593 patients (61.5%) have been exposed to any antiretroviral therapy. This proportion increased from 41.2% of patients under follow up at the end of 1996 to 71.3% of those under follow up in 2002. The median CD4 count and HIV RNA burden of patients under follow up in each year changed from 270 cells/mm3 and 4.34 log10 copies/ml in 1996 to 408 cells/mm3 and 1.89 log10 copies/ml, respectively, in 2002. By 2002, 3060 (38%) of patients who had ever been treated with antiretroviral therapy had experienced all three main classes. Of these, around one quarter had evidence of “viral load failure” with all these three classes. Patients with three class failure were more likely to have an HIV RNA burden > 2.7 log10 copies/ml and a CD4 count < 200 cells/mm3. Conclusions: The proportion of individuals with HIV infection in the United Kingdom who have been treated has increased gradually over time. A substantial proportion of these patients seem to be in danger of exhausting their options for antiretroviral treatment. New drugs with low toxicity, which are not associated with cross resistance to existing drugs, are urgently needed for such patients

Computer Games Are Serious Business and so is their Quality: Particularities of Software Testing in Game Development from the Perspective of Practitioners

Over the last several decades, computer games started to have a significant impact on society. However, although a computer game is a type of software, the process to conceptualize, produce and deliver a game could involve unusual features. In software testing, for instance, studies demonstrated the hesitance of professionals to use automated testing techniques with games, due to the constant changes in requirements and design, and pointed out the need for creating testing tools that take into account the flexibility required for the game development process. Goal. This study aims to improve the current body of knowledge regarding software testing in game development and point out the existing particularities observed in software testing considering the development of a computer game. Method. A mixed-method approach based on a case study and an opinion survey was applied to collect quantitative and qualitative data from software professionals regarding the particularities of software testing in game development. Results. We analyzed over 70 messages posted on three well-established network of question-and-answer communities related to software engineering, software testing and game development and received answers of 38 professionals discussing differences between testing a computer game and a general software, and identified important aspects to be observed by practitioners in the process of planning, performing and reporting tests in this context. Conclusion. Considering computer games, software testing must focus not only on the common aspects of a general software, but also, track and investigate issues that could be related to game balance, game physics and entertainment related-aspects to guarantee the quality of computer games and a successful testing process

Requirements engineering through viewpoints

This paper provides a short review of contributions to a better understanding of requirements engineering arising from research at Imperial College. These contributions share a common theme - a focus on “multiple perspectives” or viewpoints

Coordinating Conflicting ViewPoints by Managing Inconsistency

Support for Concurrent Engineering must address the “multiple perspectives problem” - many actors, many representation schemes, diverse domain knowledge and differing development strategies, all in the context of distributed asynchronous development. Central to this problem is the issue of managing consistency between the various elements of an emerging design. In this paper, we argue that striving to maintain complete consistency at all points in the development process is unnecessary, and an approach based on tolerance and management of inconsistency can be adopted instead. We present a scenario which highlights a number of important issues raised by this approach, and we describe how these issues are addressed in our framework of distributed ViewPoints. The approach allows an engineering team to develop independent ViewPoints, and to establish relationships between them incrementally. The framework provides mechanisms for expressing consistency relationships, checking that individual relationships hold, and resolving inconsistencies if necessary

Cryptococcal meningitis: improving access to essential antifungal medicines in resource-poor countries

Cryptococcal meningitis is the leading cause of adult meningitis in sub-Saharan Africa, and contributes up to 20% of AIDS-related mortality in low-income and middle-income countries every year. Antifungal treatment for cryptococcal meningitis relies on three old, off-patent antifungal drugs: amphotericin B deoxycholate, flucytosine, and fluconazole. Widely accepted treatment guidelines recommend amphotericin B and flucytosine as first-line induction treatment for cryptococcal meningitis. However, flucytosine is unavailable in Africa and most of Asia, and safe amphotericin B administration requires patient hospitalisation and careful laboratory monitoring to identify and treat common side-effects. Therefore, fluconazole monotherapy is widely used in low-income and middle-income countries for induction therapy, but treatment is associated with significantly increased rates of mortality. We review the antifungal drugs used to treat cryptococcal meningitis with respect to clinical effectiveness and access issues specific to low-income and middle-income countries. Each drug poses unique access challenges: amphotericin B through cost, toxic effects, and insufficiently coordinated distribution; flucytosine through cost and scarcity of registration; and fluconazole through challenges in maintenance of local stocks-eg, sustainability of donations or insufficient generic supplies. We advocate ten steps that need to be taken to improve access to safe and effective antifungal therapy for cryptococcal meningitis