Associate Professor Shamus Smith

Source code plagiarism is a common occurrence in undergraduate computer science education. In order to identify such cases, many source code plagiarism detection tools have been proposed. A source code plagiarism detection tool evaluates pairs of assignment submissions to detect indications of plagiarism. However, a plagiarising student will commonly apply plagiarism-hiding modifications to source code in an attempt to evade detection. Subsequently, prior work has implied that currently available source code plagiarism detection tools are not robust to the application of pervasive plagiarism-hiding modifications. In this article, 11 source code plagiarism detection tools are evaluated for robustness against plagiarism-hiding modifications. The tools are evaluated with data sets of simulated undergraduate plagiarism, constructed with source code modifications representative of undergraduate students. The results of the performed evaluations indicate that currently available source code plagiarism detection tools are not robust against modifications which apply fine-grained transformations to the source code structure. Of the evaluated tools, JPlag and Plaggie demonstrates the greatest robustness to different types of plagiarism-hiding modifications. However, the results also indicate that graph-based tools, specifically those that compare programs as program dependence graphs, show potentially greater robustness to pervasive plagiarism-hiding modifications.

As 3D interfaces, and in particular virtual environments, become increasingly realistic there is a need to investigate the location and configuration of information resources, as distributed in the human-computer system, to support any required activities. It is important for the designer of 3D interfaces to be aware of information resource availability and distribution when considering issues such as cognitive load on the user. This paper explores how a model of distributed resources can support the design of alternative aids to virtual environment wayfinding with varying levels of cognitive load. The wayfinding aids have been implemented and evaluated in a desktop virtual environment. © 2006 IEEE.

Hazard analysis for safety-critical systems require sufficient coverage and rigour to instill confidence that the majority of hazardous consequences have been identified. These requirements are commonly met through the use of exhaustive hazard analysis techniques. However, such techniques are time consuming and error-prone. As an attempt at exhaustive coverage, hazard analysts typically employ reuse mechanisms such as copy-and-paste. Unfortunately, if reuse is applied inappropriately there is a risk that the reuse is at the cost of rigour in the analysis. This potential risk to the validity of the analysis is dependent on the nature and amount of reuse applied. This paper investigates hazard analysis reuse over two case studies. Initially reuse in an existing safety argument is described. Argument structures within the hazard analysis are identified and the amount of verbatim reuse examined. A second study is concerned with how reuse changes as a result of tool support. In contrast to the first case, the defined arguments are more diverse - reuse has occurred but is less verbatim in nature. Although tool support has aided the customisation of the reused arguments, many are only trivially customised. An edit distance algorithm is utilised to identify and enumerate verbatim and trivial reuse in the arguments. © 2004 Elsevier Ltd. All rights reserved.

Navigation in virtual environments can be difficult. One contributing factor is user disorientation. Two major causes of this are the lack of navigation cues in the environment and problems with navigating too close to or through virtual world objects. Previous work has developed guidelines, informed by cinematography conventions, for the construction of virtual environments to aid user comprehension of virtual space to reduce user disorientation. To validate these guidelines, two user studies have been performed where users of a desktop virtual environment are to complete a navigation task in a virtual maze. In an initial study [12], collision detection with the maze walls was not enabled and the results indicated that the guidelines were effective for reducing disorientation but not for developing the user's awareness of the environment space. A second study has been performed where collision detection was enabled. Results suggest that the use of the guidelines can help reduce the incidences of user disorientation and aid navigation tasks. However, the guidelines have little impact on users' ability to construct cognitive maps of the desktop virtual environment. © Springer-Verlag London Limited 2004.

The collection and analysis of analytics incorporated into serious games provides researchers with objective data on player behavior related to serious game design elements and learning. Such analytics offer insights about play-learners engagement that is not possible to capture through traditional techniques. Visualization of learning behavior data can allow for a comparison between the pedagogical intent of the game design and the play-learners actual behavior within the serious game. This paper describes the use of game-play logs to identify pathways through gaming content in a serious game app for literacy improvement. The paper describes the technical aspects of processing game-play logs and their transformation into visualizations, and considers how these visualizations can be used to explore play-learner behavior in relation to the pedagogical intent of activities embedded in the serious game app.

There is increasing interest in the application of serious games for learning. Growth in the take-up of digital devices, e.g. smartphones and tablets, and their use for gaming provides new opportunities for mobile learning (m-learning). A serious game m-learning app for improving adult learners' apostrophe usage, called Apostrophe Power, has been developed. The research team, which consisted of software engineers and educationalists, encountered a number of discipline spanning issues while designing and developing this m-learning app. This paper overviews the issues encountered, the recommendations from recent literature and how the issues were ultimately addressed, exemplified in a case study. These lessons learnt offer insight for serious game development and highlight practical solutions for m-learning apps involving interdisciplinary teams.

The specification of virtual world objects is an important part of virtual environment design. However, identifying the required level of behaviour and geometric decomposition for virtual objects in a particular application is difficult and error-prone. This has implications for usability as the behaviour of objects gives strong cues to potential interaction. A fundamental step in tackling usability problems is the specification of virtual world objects early in the design phase. This paper presents a method for virtual object specification using task-based scenarios. Copyright the author(s) and CHISIG.

Human factors contribute to risk in safety critical systems. However, current approaches to integrating human factors issues in the development of safety critical systems appear not fully sufficient. In this paper a new approach is proposed based on a technique from chemical engineering risk analysis called Safety Modelling Language (SML). SML provides a way to conceptually design risk reduction based on barriers. The approach further helps to design and implement safety barriers. The approach is demonstrated using a case in which human factors play an important role from the medical domain. © 2004 by International Federation for Information Processing. All rights reserved.

Safety cases embody arguments that demonstrate how safety properties of a system are upheld. Such cases implicitly document the barriers that must exist between hazards and vulnerable components of a system. For safety certification, it is the analysis of these barriers that provide confidence in the safety of the system. The explicit representation of hazard barriers can provide additional insight for the design and evaluation of system safety. They can be identified in a hazard analysis to allow analysts to reflect on particular design choices. Barrier existence in a live system can be mapped to abstract barrier representations to provide both verification of barrier existence and a basis for quantitative measures between the predicted barrier behaviour and performance of the actual barrier. This paper explores the first stage of this process, the binding between explicit mitigation arguments in hazard analysis and the barrier concept. Examples from the domains of computer-assisted detection in mammography and free route airspace feasibility are examined and the implications for system certification are considered. © Springer-Verlag 2004.

It is typical for cycles of iteration to be used to refine the current state of the design of a system so that it more closely meets its requirements. Such refinements are in terms of the original requirements specification and any new requirements that have been identified during this process. However, not all defined requirements are equally essential, particularly in high consequence systems where there are issues of dependability. Although descriptive methods for scenario analysis can be used to highlight new requirements, it can be difficult to evaluate the impact of these new requirements. In this paper, we exemplify this problem and investigate how numeric methods can be used to highlight the impact of consequences identified by descriptive scenario analysis. An example from the context of human reliability analysis is presented and dependability issues for system design are considered.