Chris Exton

Commercial adoption of open source software: an empirical study

There has been a dramatic increase in commercial interest in the potential of open source software (OSS) over the past few years. However, given the many complex and novel issues that surround the use of OSS, the process of OSS adoption is not well-understood. We investigated this issue using a framework derived from innovation adoption theory which was then validated in an organisation which had embarked on a large-scale of adoption of OSS. The framework comprised four macro-factors - external environment, organisational context, technological context and individual factors. We then investigated these factors in a large-scale survey. Overall, the findings suggest a significant penetration of OSS with general deployment in two industry sectors - consultancy/software house and service/communication - and more limited deployment in government/public sector. However, the existence of a coherent and planned IT infrastructure based on proprietary software served to impede adoption of OSS. Finally, individual-relevant factors such as support for the general OSS ideology and committed personal championship of OSS were found to be significant.

An empirical analysis of information retrieval based concept location techniques in software comprehension

Concept location, the problem of associating human oriented concepts with their counterpart solution domain concepts, is a fundamental problem that lies at the heart of software comprehension. Recent research has attempted to alleviate the impact of the concept location problem through the application of methods drawn from the information retrieval (IR) community. Here we present a new approach based on a complimentary IR method which also has a sound basis in cognitive theory. We compare our approach to related work through an experiment and present our conclusions. This research adapts and expands upon existing language modelling frameworks in IR for use in concept location, in software systems. In doing so it is novel in that it leverages implicit information available in system documentation. Surprisingly, empirical evaluation of this approach showed little performance benefit overall and several possible explanations are forwarded for this finding.

Fault detection and prediction in an open-source software project

Software maintenance continues to be a time and resource intensive activity. Any efforts that help to address the maintenance bottleneck within the software lifecycle are welcome. One area where such efforts are useful is in the identification of the parts of the source-code of a software system that are most likely to contain faults and thus require changes. We have carried out an empirical study where we have merged information from the CVS repository and the Bugzilla database for an open-source software project to investigate whether or not parts of the source-code are faulty, the number and severity of faults and the number and types of changes associated with parts of the system. We present an analysis of this information, showing that Paretos Law holds and we evaluate the usefulness of the Chidamber and Kemerer metrics for identifying the fault-prone classes in the system analysed.

Improving delirium care through early intervention: from bench to bedside to boardroom

Delirium is a complex neuropsychiatric syndrome that impacts adversely upon patient outcomes and healthcare outcomes. Delirium occurs in approximately one in five hospitalised patients and is especially common in the elderly and patients who are highly morbid and/or have pre-existing cognitive impairment. However, efforts to improve management of delirium are hindered by gaps in our knowledge and issues that reflect a disparity between existing knowledge and real-world practice. This review focuses on evidence that can assist in prevention, earlier detection and more timely and effective pharmacological and non-pharmacological management of emergent cases and their aftermath. It points towards a new approach to delirium care, encompassing laboratory and clinical aspects and health services realignment supported by health managers prioritising delirium on the healthcare change agenda. Key areas for future research and service organisation are outlined in a plan for improved delirium care across the range of healthcare settings and patient populations in which it occurs.

Constructivism and program comprehension strategies

Program comprehension strategies and learning theories are difficult topics in themselves, and the combination of both can provide some interesting observations. Constructivism differs from the traditional learning theories which suggest knowledge exists as something independent of the individual in several ways. One major premise of constructivism is that we actively construct our knowledge rather than simply absorbing it through repeated practice or predefined steps. Constructivism asserts that there is no knowledge independent of that constructed by the learner, and its construction is a unique experience for each individual. This paper provides an overview of existing program comprehension strategies and contrasts them in relation to the learning theory of constructivism.

Fluid Source Code Views

Fluid documents enable the interactive incorporation of related material into a primary document. Visual cues within primary material indicate that related content is available and user interaction reveals related content in context. Fluid documents reduce the need for explicit navigation, maintain context when considering related material and support synthesization of disjoint yet related information. Source code documents are an excellent medium for the application of fluid document technology. The definition of software in the form of text based documents manifests a highly linked and fragmented information space requiring considerable navigation between elements during code examination and comprehension. In this paper we present fluid source code views, the application of fluid document technology to source code documents

Eclipse plug-in to monitor the programmer behaviour

Comprehending and maintaining software is one of the core software engineering activities from early implementation to long-term software evolution. This paper describes an Eclipse based tool, which provides some quantitative insights into how different programmers develop and maintain software. In addition it presents a comparative pilot study that utilised the tool on a number of student programmers to gain insights in to how they utilise an interactive Development Environment.

CHIVE - a program source visualisation framework

The CHIVE visualisation framework is an attempt to provide program comprehension and visualisation tool developers with a flexible means for creating 3-dimensional visualisations of hierarchies such as those that occur in program source. The CHIVE framework supports user definable datasets, multiple graph layouts and an environment in which users can interact with visualisations created from applying a graph layout to a dataset.

The Cognitive Assignment Eclipse Plug-in

Concept assignment approaches assist software engineers to comprehend software by localising problem domain concepts to source code elements. This paper presents an implementation of a concept assignment approach we call cognitive assignment which combines cognitive mapping of expert software engineers and Bayesian classification to help engineers tasked with understanding unfamiliar systems to localise a concepts implementation in the systems source

Attention, vigilance and visuospatial function in hospitalized elderly medical patients: Relationship to neurocognitive diagnosis

OBJECTIVE Efficient detection of neurocognitive disorders is a key diagnostic challenge. We explored how simple bedside tests of attention, vigilance and visuospatial function might assist in identifying delirium in hospitalized patients. METHODS Performance on a battery of bedside cognitive tests was compared in elderly medical inpatients with DSM-IV delirium, dementia, comorbid delirium-dementia, and no neurocognitive disorder. RESULTS 193 patients [mean age 79.9±7.3; 97 male] were assessed with delirium (n=45), dementia (n=33), comorbid delirium-dementia (n=65) and no neurocognitive disorder (NNCD) (n=50). The ability to meaningfully engage with the tests varied from 84% (Spatial Span Forwards) to 57% (Vigilance B test), and was especially problematic among the comorbid delirium-dementia group. The NNCD was distinguished from the delirium groups for most tests, and from the dementia group for the Vigilance B test and the Clock Drawing Test. The dementia group differed from delirium groups in respect of the Months Backward Test, Vigilance A and B tests, Global assessment of visuospatial ability and the Interlocking Pentagons Test. Overall, patients with delirium were best identified by three tests - the Months Backward Test, Vigilance A test and the Global Assessment of visuospatial function with failure to correctly complete any two of these predicting delirium status in 80% of cases. CONCLUSION Simple bedside tests of attention, vigilance and visuospatial ability can help to distinguish neurocognitive disorders, including delirium, from other presentations. There is a need to develop more accurate methods specifically designed to assess patients with neurocognitive disorder who are unable to engage with conventional tests.