A preliminary evaluation of text-based and dependency-based techniques for determining the origins of bugs

A crucial step in understanding the life cycle of software bugs is identifying their origin. Unfortunately this information is not usually recorded and recovering it at a later date is challenging. Recently two approaches have been developed that attempt to solve this problem: the text approach and the dependency approach. However only limited evaluation has been carried out on their effectiveness so far, partially due to the lack of data sets linking bugs to their introduction. Producing such data sets is both time-consuming and challenging due to the subjective nature of the problem. To improve this, the origins of 166 bugs in two open-source projects were manually identified. These were then compared to a simulation of the approaches. The results show that both approaches were partially successful across a variety of different types of bugs. They achieved a precision of 29%{79% and a recall of 40%{70%, and could perform better when combined. However there remain a number of challenges to overcome in future development|large commits, unrelated changes and large numbers of versions between the origin and the x all reduce their effectiveness

Space photography and the exploration of Mars

A general exposition of the scientific potentialities and analytic framework of space photography is presented using the photography of Mars from flybys and orbiters as the principal example. Space photography is treated here as a communication process in which planetary scene information is communicated to the eye-brain receiver of earth-based interpreters. The salient parameters of this process are: (1) total information returned, (2) surface resolution, and (3) a priori knowledge regarding the planetary surface observed

Comparing text-based and dependence-based approaches for determining the origins of bugs

Identifying bug origins – the point where erroneous code was introduced – is crucial for many software engineering activities, from identifying process weaknesses to gathering data to support bug detection tools. Unfortunately, this information is not usually recorded when fixing bugs, and recovering it later is challenging. Recently, the text approach and the dependence approach have been developed to tackle this problem. Respectively, they examine textual and dependence-related changes that occurred prior to a bug fix. However, only limited evaluation has been carried out, partially because of a lack of available implementations and of datasets linking bugs to origins. To address this, origins of 174 bugs in three projects were manually identified and compared to a simulation of the approaches. Both approaches were partially successful across a variety of bugs – achieving 29–79% precision and 40–70% recall. Results suggested the precise definition of program dependence could affect performance, as could whether the approaches identified a single or multiple origins. Some potential improvements are explored in detail and identify pragmatic strategies for combining techniques along with simple modifications. Even after adopting these improvements, there remain many challenges: large commits, unrelated changes and long periods between origins and fixes all reduce effectiveness

Public Institutions, People, and Famine Mitigation

Summary Taking the specific example of famine induced by the shock of drought, this article explores institutional barriers to linking relief and development within a four stage framework of preparedness, mitigation, relief and rehabilitation. At national level, institutional constraints are the rock on which the good intentions implicit in linking relief and development founder, in both government structures and donor agencies. At local level, households, communities and civil society institutions are also under increasing stress. Building on the principle of subsidiarity, the greatest opportunities for overcoming constraints and building on strengths are at the intermediate, or meso level. Resumé Les institutions publiques, les populations, et l'aide d'urgence de la famine Cet article, qui prend comme point de départ la famine causée par l'impact de la sécheresse, explore les barrières institutionnelles qui empêchent d'allier l'aide d'urgence au développement au sein d'une structure quadripartite de préparation, d'atténuation, d'aide d'urgence et de réhabilitation. Au niveau national, les contraintes institutionnelles sont le récif sur lequel viennent s'écraser les bonnes intentions qui se manifestent dans le désir des structures gouvernementales et des agences donatrices de lier l'aide d'urgence au développement. Au niveau local, les ménages, les communautés et les institutions de la société civile font face à des contraintes de plus en plus sévères. Si l'on respecte le principe de la subsidiarité, les meilleures possibilités de vaincre ces contraintes et de bâtir sur des fondations existantes se perçoivent au niveau intermédiaire, dit “meso”. Resumen Las instituciones publicas, la gente y la mitigación del hambre Con el ejemplo específico del hambre ocasionada por la sequía repentina, este artículo explora las barreras institucionales para la integración entre asistencia y desarrollo dentro del marco de las cuatro etapas de preparación, mitigación, asistencia y rehabilitación. A nivel nacional, las limitaciones institucionales representan una barrera contra la cual chocan todas las buenas intenciones implícitas en el proceso de integración, tanto en estructuras gubernamentales como en agencias asistenciales. A nivel local, familias, comunidades y estructuras sociales sufren una presión constante. Partiendo del principio de subsidiariedad, las mejores oportunidades para superar limitaciones y reforzar los puntos positivos se encuentran en el nivel intermedio

Planets in 47 Tuc

We consider the survivability of planetary systems in the globular cluster 47 Tucanae. We compute the cross sections for the breakup of planetary systems via encounters with single stars and binaries. We also compute the cross sections to leave planets on eccentric orbits. We find that wider planetary systems (d > 0.3 AU) are likely to be broken up in the central regions of 47 Tucanae (within the half-mass radius of the cluster). However tighter systems, and those in less-dense regions may survive. Tight systems will certainly survive in less-dense clusters where subsequent surveys should be conducted.Comment: 6 pages, 4 figures; accepted for MNRA

Accuracy of diagnosing atrial fibrillation on electrocardiogram by primary care practitioners and interpretative diagnostic software: analysis of data from screening for atrial fibrillation in the elderly (SAFE) trial

Objective To assess the accuracy of general practitioners, practice nurses, and interpretative software in the use of different types of electrocardiogram to diagnose atrial fibrillation. Design Prospective comparison with reference standard of assessment of electrocardiograms by two independent specialists. Setting 49 general practices in central England. Participants 2595 patients aged 65 or over screened for atrial fibrillation as part of the screening for atrial fibrillation in the elderly (SAFE) study; 49 general practitioners and 49 practice nurses. Interventions All electrocardiograms were read with the Biolog interpretative software, and a random sample of 12 lead, limb lead, and single lead thoracic placement electrocardiograms were assessed by general practitioners and practice nurses independently of each other and of the Biolog assessment. Main outcome measures Sensitivity, specificity, and positive and negative predictive values. Results General practitioners detected 79 out of 99 cases of atrial fibrillation on a 12 lead electrocardiogram (sensitivity 80%, 95% confidence interval 71% to 87%) and misinterpreted 114 out of 1355 cases of sinus rhythm as atrial fibrillation (specificity 92%, 90% to 93%). Practice nurses detected a similar proportion of cases of atrial fibrillation (sensitivity 77%, 67% to 85%), but had a lower specificity (85%, 83% to 87%). The interpretative software was significantly more accurate, with a specificity of 99%, but missed 36 of 215 cases of atrial fibrillation (sensitivity 83%). Combining general practitioners' interpretation with the interpretative software led to a sensitivity of 92% and a specificity of 91%. Use of limb lead or single lead thoracic placement electrocardiograms resulted in some loss of specificity. Conclusions Many primary care professionals cannot accurately detect atrial fibrillation on an electrocardiogram, and interpretative software is not sufficiently accurate to circumvent this problem, even when combined with interpretation by a general practitioner. Diagnosis of atrial fibrillation in the community needs to factor in the reading of electrocardiograms by appropriately trained peopl

Affective reactions to auditory hallucinations in psychotic, evangelical and control groups

Objectives: Building on recent work on the similarities and differenes in delusional ideation between psychotic and religious populations (Peters, Day, McKenna, and Orbach, 1999), the experiences of auditory hallucinations in psychotic, evangelical and control groups were examined in this study. -- Method: The incidence and subjective experiences of hearing voices were assessed using questionnaire methods in psychotic out-patients, evangelical Christians and controls (non-psychotic, non-evangelical). -- Results: Incidence of auditory hallucinations differend significantly across the three groups with psychotics showing the highest levels and controls the lowest levels. The experiences of the evangelical group were significantly more positive than those of the control group, which in turn were significantly more positive than those of the psychotic group. The most recent experience of hearing voices was rated more positively than the first experience by the psychotic and religious groups but not by the control group. These findings were much stronger for affective reactions to the experiences than for perceptions of the voices. -- Conclusion: These results provide only partial support for the findings of Peters et al. (1999) on differences in delusional ideation and possible reasons for this are discussed. The findings for religious and psychotic individuals are discussed further in terms of interpretational and coping mechanisms

Using information technology to communicate about health and wellbeing, assessment and review : audio computer assisted self-interviewing (A-CASI)

The development and growth of information technology in the past decade has changed the face of communication at both a personal and an organisational level. As young people and practitioners become more familiar with its applications, it seems pertinent to think about how it can be applied more widely in relation to health and wellbeing in residential child care settings. An increasing number of local authorities are introducing audio computer assisted self-interviewing (A-CASI) as a method for improving communication with young people in their care. Self-completion methods in general are viewed as advantageous, in comparison to other approaches, in terms of being cheaper and quicker to administer and also in terms of minimizing the under-reporting of issues that could be sensitive (De Vaus, 1996). A-CASI approaches have been identified as being of particular benefit in conducting research with particular groups, such as children and young people and have also been associated with aiding literacy difficulties, with an enhanced sense of privacy and with increased disclosure of sensitive information (De Leeuw et al., 1997; Borgers et al., 2000; Borgers et al., 2004). In addition, its use is thought to decrease respondent error or fatigue and allows the relatively easy use of more complicated questionnaires, providing richer data than other self-completion approaches (Tourangeau and Smith, 1996)