Technical Reports at the Centre for Research in Computing


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[1] Pete Thomas. Grading diagrams automatically. Technical Report 2004/01, 2004. [ bib | .pdf ]
This paper describes a feasibility study into the marking (grading) of diagrams automatically. The diagrams were produced by students during an on-line examination using a simple drawing tool. The students' examination answers, which included a diagram, were submitted over the Internet to an automatic marking tool for grading. This paper describes the methodology adopted by the diagram marking tool and comments on the results achieved. Whilst only a small number of diagrams were available for marking, the grades awarded by the automatic marker were sufficiently close to the marks awarded by four independent human markers to suggest that marking diagrams automatically, for small diagrams at least, is feasible and should be pursued further.

[2] Patrick Hill, Simon Holland, and Robin Laney. Using dynamic aspects in music composition. Technical Report 2004/02, 2004. [ bib | .pdf ]
Aspect-oriented programming (AOP) attempts to modularisecrosscutting concerns in software. Initial approaches to AOP haveused static weaving techniques in which crosscuttingimplementation, encapsulated by aspects, is merged into . Research into dynamic aspects suggests various ways in which crosscutting implementations may be dynamically woven into code, enabling aspects to be defined and composed at run-time.It has been suggested, in [14], that AOP might be usefully appliedat the end-user level in applications that support multidimensionalcreative processes, and in particular, of music composition. In thispaper we extend this argument to suggest that dynamic aspects are essential to this application. We motivate our argument with ahigh-level description of crosscutting that exists within musiccomposition, and ways in which these crosscutting concerns, andrequirements for their management, have arisen from our initialuse of static aspects in music composition. We then evaluate someof the ways in which current research into dynamic aspects mightbe utilised in addressing these requirements.

[3] Robin Laney, Leonor Barroca, Michael Jackson, and Bashar Nuseibeh. Composing requirements using problem frames. Technical Report 2004/03, 2004. [ bib | .pdf ]
Problem Frames are a systematic approach to thedecomposition of problems that allows us to relaterequirements, domain properties, and machinespecifications. Having decomposed a problem, oneapproach to solving it is through a process ofcomposing solutions to sub-problems. In this paper,we contribute to supporting such a process byproviding a way to compose multiple ProblemFrames. We develop a systematic approach tocomposing inconsistent requirements. We introduceComposition Frames, a requirements construct thatmodels relevant aspects of composition and thus dealswith unwanted effects, such as interference ofoverlapping reactions to events. Throughout the paperwe use a simple case study to illustrate and validateour ideas.

[4] Max Garagnani. A framework for hybrid planning. Technical Report 2004/04, 2004. [ bib | .pdf ]
Hybrid models are characterised by the integration of two(or more) different paradigms of representation within the same system. Most current planning problem description languages are purely sentential, i.e., based on predicate logic formalisms [3, 14]. The ramification of the effects of action [16] makes the sentential description of planning problems that involve the spatial movement of physical entities over-complex and inefficient. Evidence from research in knowledge representation and planning [6, 9, 8] indicates that these problems are more effectively modelled using homomorphic [1] (or analogical) representations. As for sentential descriptions, however, the complexity of the real world prevents purely homomorphic formalisms from being always the most effective choice. This paper proposes a model-based theoretical framework for planning with hybrid representations, in which equivalent sentential and analogical models can be simultaneously and interchangeably used. The analogical model which is developed extends a recently proposed representationfor purely homomorphic planning [5]. The sentential model of actionadopted is based on the current standard planning domain description language PDDL2.1 [3]. The result is a powerful, heterogeneous planning representation that overcomes the limitations and offers the complementary strenghts of the two formalisms on which it relies.

[5] A. Sarkar, A. De Roeck, and P. Garthwaite. Easy measures for evaluating non-english corpora for language engineering. some lessons from arabic and bengali. Technical Report 2004/05, 2004. [ bib | .pdf ]
In this paper we develop a framework for fast profiling and quality verification of datasets for language engineering and information retrieval research. The profiling steps consist of an initial tokenization of the corpus to produce a frequency list from which some basic statistics are derived. Manual sampling is carried out to detect obvious discrepancies. Two diagnostic tests are performed to check for sparseness related measures. The behaviour of the function words is traced to gauge homogeneity of their distribution in documents.

[6] A. De Roeck, A. Sarkar, and P. Garthwaite. Frequent term distribution measures for dataset profiling. Technical Report 2004/06, 2004. [ bib | .pdf ]
We motivate the need for dataset profiling in the context of evaluation, and show that textual datasets differ in ways that challenge assumptions about the applicability of techniques. We set out some criteria for useful profiling measures. We argue that distribution patterns of frequent words are useful in profiling genre, and report on a series of experiments with Chi-square based measures on the TIPSTER collection, and on textual intranet data. Findings show substantial differences in the distribution of very frequent terms across datasets.

[7] A. De Roeck, A. Sarkar, and P. Garthwaite. Defeating the homogeneity assumption: some findings on the distribution of very frequent terms. Technical Report 2004/07, 2004. [ bib | .pdf ]
The statistical NLP and IR literatures tend to make a -homogeneity assumption about the distribution of terms, either by adopting a -bag of words model, or in their treatment of function words. In this paper we develop a notion of homogeneity detection to a level of statistical significance, and conduct a series of experiments on different datasets, to show that the homogeneity assumption does not generally hold. We show that it also does not hold for function words. Importantly, datasets and document collections are found not to be neutral with respect to the property of homogeneity, even for function words. The homogeneity assumption is defeated substantially even for collections known to contain similar documents, and more drastically for diverse collections. We conclude that it is statistically unreasonable to assume that word distribution within a corpus is homogeneous. Because homogeneity findings differ substantially between different collections, we argue for the use of homogeneity measures as a means of profiling datasets.

[8] Robert Day, Simon Holland, David Bowers, and Anton Dil. Using spatial audio in minimal attention interfaces: Towards an effective audio gps navigation system. Technical Report 2004/08, 2004. [ bib | .pdf ]
This paper builds on previous empirical work (Holland et al, 2002) and discusses the potentialfor spatial audio to be used in minimal attention user interfaces, and in the context of navigationaltasks. Spatial audio in this context is closely related to 3-d audio or virtual audio. The benefits of aspatial audio system for users are highlighted, with particular attention given to in-car systems. In-carsystems have been chosen due to their inherent and heightened need for minimal attention interaction,and for the purposes of illustration. Current in-car navigation technology is critically discussed, withattention to potential issues that the proposed spatial audio system may address. Alternative spatialaudio systems, such as those developed for the visually impaired, are also highlighted and discussedwith reference to the implications of differences (and similarities) to the proposed system. The relativeimportance of psychoacoustics is suggested in terms of guiding the appropriate spatial audio systemdesign. Current issues surrounding spatial audio technology are discussed, and implications for theproposed system are highlighted. Areas of potential investigation are taken from existing research andsuggestions for further work to be undertaken are made.

[9] Adrian J. Hilton and Jon G. Hall. Developing critical systems with pld components. Technical Report 2004/09, 2004. [ bib | .pdf ]
Programmable logic devices (PLDs) are now common componentsof critical systems, and are increasingly used for safety-relatedor safety-critical functionality. Since 1999 avionics- and defence-related safety standards have advised and prescribed various approaches for PLD programming in safety-related systems. There are many differences between current and recommended practice, and safety engineers differ on how to apply the existing standards.This paper describes past and current practice in programming PLDs in critical systems. It summarises the relevant safety and security standards and anticipates forthcoming changes to UK standards. It describes the work that the authors and others have done in the field of specifying, designing and proving correct PLD programs and maps out avenues of work that the authors believe necessary for PLD programming technology to keep pace with PLD functionality.

[10] Helen Sharp, Hugh Robinson, and Judith Segal. Customer collaboration: successes and challenges in practice. report of an activity session held at xp 2003. Technical Report 2004/10, 2004. [ bib | .pdf ]
This paper reports on an activity session held at XP2003 in Genoa, Italy in May 2003. The intention of the session was to collect experience of customer collaboration in XP projects with the intention of identifying common models, their critical success factors and their pitfalls. As reported in the books, XP expects an on-site customer, i.e. someone co-located with the development team who is able to make decisions about required functionality and funding while at the same time representing the real users of the product. Anecdotal evidence has suggested that this model is not widely used, and the results of this session confirm that there are many different successful models used in practice.

[11] Shailey Minocha, Liisa Dawson, Dave Roberts, and Nicola Millard. Integrating service quality into customer-centred design approach of e-commerce environments. Technical Report 2004/11, 2004. [ bib | .pdf ]
With an increasing competition in the E-market place, generating experiences that exceed the customer's expectations of E-Commerce is important in order to acquire and then retain customers. A customer's experience with E-Commerce environments extends beyond the interaction with the Web site, including, delivery of products, post-sales support, and so on. It is this total experience that influences the customer's perceptions of value and service quality. Our research goal has been to investigate how Customer Relationship Management (CRM) strategies can be incorporated into the design of E-Commerce. In our cross-disciplinary research programme in HCI and CRM, we have developed an empirically-grounded evaluation instrument called E-SEQUAL, and a generic set of customer personas and their task scenarios for E-Commerce. E-SEQUAL consists of CRM and usability heuristics which can be applied to integrate customers' perceived dimensions of service quality into the design and evaluation of E-Commerce. In this paper we describe a customer-centred design process for E-Commerce which integrates E-SEQUAL, customer personas, and task scenarios of the personas.

[12] Shailey Minocha, Liisa Dawson, Dave Roberts, and Marian Petre. E-sequal: A customer-centred approach to providing value in e-commerce environments. Technical Report 2004/12, 2004. [ bib | .pdf ]
With an increasing competition in the E-market place, generating experiences that exceed the customer's expectations is important in order to acquire and then retain customers. A customer's experience with E-Commerce extends beyond the interaction with theWeb site. Other features such as credit card handling, delivery of products, post-sales support, and so on, influence the customer's perceptions of value and service quality. Our research goal has been to investigate how, in addition to usability, Customer Relationship Management (CRM) strategies can be incorporated into the design of E-Commerce. In our cross-disciplinary research programme we have applied a variety of techniques to investigate customers' expectations and perceptions of service quality. In this paper we describe a framework called E-SEQUAL. E-SEQUAL is an evaluation instrument consisting of CRM and usability heuristics which can be applied to integrate customers' perceived dimensions of service quality into the design andevaluation of E-Commerce.

[13] Leonor Barroca, Jose L. Fiadeiro, Michael Jackson, and Robin Laney. Dynamic assembly of problem frames. Technical Report 2004/13, 2004. [ bib | .pdf ]
This paper addresses the support of modular, compositional andincremental analysis and design of software systems by the assembly of problem frames. We use coordination-based techniques to put in place an architectural layer in which, for each subproblem, we provide a description of the machine and the way it is interconnected with the components of the problem domain tofulfill given customer requirements. Composition in this architectural layer is dynamic in the sense that it is not constrained to follow pre-established decomposition structures; instead, it allows fully incremental development. The architectural layer provides a basis on which we will be able to support reconfiguration of the system at execution time by the addition or substitution of new machines or new problem domain components resulting from new requirements.

[14] Pete Thomas. Drawing diagrams in an online examination. Technical Report 2004/14, 2004. [ bib | .pdf ]
This paper describes a study into the drawing of diagrams in an online examination. The diagrams were produced by students during an on-line examination using a simple drawing tool. The students' examination answers, which included a diagram, were submitted over the Internet to an automatic marking tool for grading and feedback. This paper describes the diagram drawing tool and discusses the students' reactions to its use under examination conditions. Whilst only a small number of students were involved in the trials, drawing simple diagrams using a software tool during an examination did not pose major problems for most of them. We conclude that the use of such a tool is feasible and should be investigated further.

[15] Allan Seago. Analysis of the synthesizer user interface: cognitive walkthrough and user tests. Technical Report 2004/15, 2004. [ bib | .pdf ]
The aim of this report is to analyse the user interfaces of two electronic synthesisers and to report the results of user tests conducted on these interfaces.Work on interface design in the sound synthesis domain here has tended to focus on the development of experimental input devices which capture physical gestures, and which are mapped to synthesis parameters. However, relatively little attention has been given to the analysis of existing audio and music related hardware and software (e.g. electronic synthesizers) from the HCI perspective. In the context of HCI, sound has, for the most part, only been considered as a means of providing warning or monitoring feedback to users of systems in which it otherwise does not play a role [1]. Auditory interfaces have sought to present data, which would normally be presented visually, in aural form, sometimes for the benefit of users with visual impairments [2][7][13]. Studies of software/hardware interfaces in which the creation, editing and storage of audio material is the prime focus are scarce, however [8] [15].Ruffner and Coker's review of synthesizer interface design [15] focused on the control surfaces of four contemporary instruments, and commented on the degree to which they conformed to design principles identified by Williges et al. [16] They concluded that the demands placed on the user by the interfaces made them far from ideal for the purpose: noting that, in general 'user interface principles have been, at best haphazardly applied' in the design of the synthesizer interface, the authors also suggested a number of issues that should drive future research in this area. Another more recent study [5] has applied an heuristic evaluation to an electric guitar pre-amplifier interface.As well as critically examining the control surfaces of the two instruments, the types of controllers and their layout, the study presented in this paper will seek to examine the user/system interaction required to complete three tasks typical of these instruments, firstly, by using the `cognitive walkthrough' technique, and secondly, through a number of user tests.The two synthesizers to be examined are the Roland XP50 and the Korg Trinity. The internal sound generation mechanisms of these instruments are broadly the same, using PCM samples as the basic waveform library, but using techniques derived from traditional analogue subtractive synthesis to process them [4].

[16] Robert Day, Simon Holland, David Bowers, and Anton Dil. Audio navigation: Using spatial audio in ubiquitous interfaces. Technical Report 2004/16, 2004. [ bib | .pdf ]
An important current movement in computing is towards mobile and ubiquitous interaction. A major research field within mobile and ubiquitous computing is minimal attention interfaces. At present however, there is little in the way of validated heuristics to inform the design and implementation of minimal attention user interfaces. A paradigmatic example of a challenging mobile interaction task is physical navigation. A potentially promising solution to the problem of providing a minimal attention interface for physical navigation tasks is spatial audio. The initial focus of this research is to investigate the use of spatial audio as an element in a minimal attention interface to provide usable and meaningful navigation cues in one or more common navigational contexts. The aims of this project are to highlight problems, identify and analyse issues and evaluate potential solutions. Finally, we intend to formulate guidelines for the use of spatial audio in the wider context of minimal attention interfaces.

[17] Patrick Hill, Simon Holland, and Robin C. Laney. Applying aspect-oriented programming to music computing. Technical Report 2004/17, 2004. [ bib | .pdf ]
Computer programs for the composition, performance and analysis of music generally involve the tangled interaction of many dimensions of musical and extra-musical concern. In thispaper we introduce the concepts of Aspect-Oriented Programming (AOP) to Music Computing and argue that AOP and related techniques and technologies form an appropriate solution to the separation and composition of such concerns. We motivate our argument with simple examples from the musical domain, but argue that the underlying principles may be applied to a wide and expressive range of musical applications.

[18] Debra T. Haley, Bashar Nuseibeh, Helen C. Sharp, and Josie T. Taylor. Managing requirements for mobile learning. Technical Report 2004/18, 2004. [ bib | .pdf ]
This paper reports on the experience of eliciting and managing requirements on a large European-based multinational project, whose purpose is to create a system to support learning using mobile technology. The project used the socio-cognitive engineering methodology for human-centered design and the Volere shell and template to document requirements.We provide details about the project below, describe the Volere tools, and explain how and why we used a flexible categorization scheme to manage the requirements. Finally, we discuss three lessons learned: (1) provide a flexible mechanism for organizing requirements, (2) plan ahead for the RE process, and (3) do not forget the waiting room.

[19] Simon Holland. A simple taxonomy of search reduction in direct combination. Technical Report 2004/19, 2004. [ bib | .pdf ]
Direct Combination (DC) is a new interaction principle with thecapacity to reduce users' search, particularly when interactions involve more than one object or device. The principle applies to arbitrary combinations of physical objects, virtual objects, remote objects, and subparts of objects.In this paper we distinguish between several different ways in which Direct Combination can be used to reduce search, as identified in a preliminary evaluation of a prototype DC interface.

[20] Allan Seago, Simon Holland, and Paul Mulholland. Synthesizer user interface design - lessons learned from a heuristic review. Technical Report 2004/20, 2004. [ bib | .pdf ]
In this paper, we review the types of user interfaces used in electronic synthesizers, both hardware and software, and conduct a heuristic review on a number of representative examples. The process of building and editing sounds in modern commercial synthesizers requires a good understanding, both of the system architecture and of the synthesis engine itself, as the user/system dialog is conducted in system-specific terms, rather than in terms familiar to a musician. User interfaces of contemporary synthesizers may be procedural, presenting the user with a set of functional modules which generate/process sound, or alternatively, offer the means of creating/editing sound, using direct manipulation techniques. We conclude that neither style emerges as being better suited to the task of sound synthesis; in this domain, direct manipulation is limited in the degree of control afforded, while the form filling style characteristic of fixed architecture synthesizers is slow and laborious.

[21] Allan Seago, Simon Holland, and Paul Mulholland. A critical analysis of synthesizer user interfaces for timbre. Technical Report 2004/21, 2004. [ bib | .pdf ]
In this paper, we review and analyse some categories of user interface for hardware and software electronic music synthesizers. Problems with the user specification and modification of timbre are discussed. Three principal types of user interface for controlling timbre are distinguished. A problem common to all three categories is identified: that the core language of each category has no well-defined mapping onto the task languages of subjective timbre categories used by musicians.

[22] Allan Seago. Electronic sound synthesizer interface design. Technical Report 2004/22, 2004. [ bib | .pdf ]
The focus of this project described in this paper is to address a deep-rooted problem in the user interface of present-day hardware and software of electronic music synthesizers. While sound qualities such as pitch and loudness lend themselves relatively easily to user control, the timbre of sound is much less easily described or defined in any systematic way. Consequently, in all present day user interfaces so far examined for controlling or modifying timbre in electronic synthesisers, there is a wide semantic gap between the task and system languages used. In this project, we are carefully analysing current approaches to controlling timbre, and investigating principles, issues and problems that must be addressed to improve the design of user interfaces for sound synthesis. In subsequent stages of the project, a prototype of a new kind of interface will be designed, implemented and evaluated.The research is still in its early stages, but a taxonomy of synthesizer interface design categories is identified and the conclusions drawn from a series of user tests summarised.

[23] Jonathan D. Moffett, Charles B. Haley, and Bashar Nuseibeh. Core security requirements artefacts. Technical Report 2004/23, 2004. [ bib | .pdf ]
Although security requirements engineering has recently attracted increasing attention, it has lacked a context in which to operate. A number of papers have described how security requirements may be violated, but apart from a few hints in the general literature, none have described satisfactorily what security requirements are.This paper proposes a framework of core security requirements artefacts, which unifies the concepts of the two disciplines of requirements engineering and security engineering. From requirements engineering it takes the concept of functional goals, which are operationalised into functional requirements, with appropriate constraints. From security engineering it takes the concept of assets, together with threats of harm to those assets. Security goals aim to protect from those threats, and are operationalised into security requirements, which take the form of constraints on the functional requirements.In addition we explore the consequences of the fact that security is concerned with the protection of assets, while computers only provide interfaces. We show how to specify the relationship between security requirements and the specification of software behaviour, using Jackson's Problem Frames approach.

[24] Jon G. Hall, Lucia Rapanotti, Karl Cox, Steven Bleistein, and June Verner. An example of domain decomposition through application of the problem frames approach to a complex problem. Technical Report 2004/24, 2004. [ bib | .pdf ]
It is critical to decompose problem context of real world problems in order to understand requirements and specifications for IT systems. However, this is far from trivial. In this paper, we present an example problem domain contextual decomposition that provides a means of ensuring high-level requirements, such as business requirements, are met by lower-level requirements that are closer to the software to be delivered. We use Jackson's Problem Frames approach to describe organisational context, and apply Architectural Frames (AFrames) to simultaneously decompose and simplify the problem context and hence requirements. Through AFrame application, and problem decomposition and projection, we show how socio-technical elements can also be described in our solution. We validate our approach through a case study taken from the literature of Seven-Eleven Japan.

[25] Judith Segal. Professional end user developers and software development knowledge. Technical Report 2004/25, 2004. [ bib | .pdf ]
This paper seeks to explore how IT professionals might best support professional end user development. By 'professional end users', we mean practitioners of some recognized technical, scientific or mathematical profession, who develop software in order to further their professional goals. Our field studies demonstrate that such software development takes place within a culture in which it is perceived as being very much a secondary activity, and this perception may be reflected in the inadequate allocation of resources both for the development of software and for the acquisition, creation and sharing of knowledge of both software development and the software product. We suggest that importing some practices from eXtreme Programming might ameliorate (though not entirely solve) these problems of knowledge creation and sharing.

[26] Zhi Li, Jon G. Hall, and Lucia Rapanotti. A constructive approach to problem frame semantics. Technical Report 2004/26, 2004. [ bib | .pdf ]
The Problem Frame approach (PF) is an effective requirements engineering tool for analysing and structuring software development problems. PF has a graphical notation that is easy to use and understand. PF imposes only loose constraints on the features of the language used to describe its components and, with only slight restrictions, Hoare's CSP can be used. Although not generally applicable, in this paper we show that CSP can provide a constructive way to arrive at a solution to a PF expressed problem.The work is situated in the Problem Frame Semantics for Software Development of Hall, Rapanotti and Jackson.

[27] Pete Thomas. Comparing machine graded diagrams with human markers: some observations. Technical Report 2004/27, 2004. [ bib | .pdf ]
In this paper we examine the performance of an automatic (machine) grading algorithm for entity-relationship (E-R) diagrams by comparing it with human generated marks for a set of student answers to an assignment question. Using a variety of statistical tests it is shown that the performance of the automatic marker is very close to that of the human markers: the Pearson correlation coefficient is 0.964 (significant at the 0,01 level, 2-tailed, N=26) and the Kendall tau-b correlation coefficient is 0.919 (significant at the 0.01 level, 2-tailed, N=26). The investigation revealed deficiencies in both the machine and human markers. There is prima-facie evidence that the orientation (shape) of a diagram may influence humans to award lower marks than they should.


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