Steve Pettifer | The University of Manchester (original) (raw)

Papers by Steve Pettifer

The Distributed Legible City (DLC) is an interactive multi-media art installation enabling a numb... more The Distributed Legible City (DLC) is an interactive multi-media art installation enabling a number of 'cyclists' to participate in a shared virtual environment and to tour together around three city representations. In this paper we describe the evolution of the DLC guided by ethnographic study. In particular we consider the implications and problems associated with designing a virtual environment where the requirements, such 'support social interaction' are ambiguous and open ended.

This paper describes the evaluation of Kekulé, software designed to allow visually impaired users... more This paper describes the evaluation of Kekulé, software designed to allow visually impaired users to explore the structures of chemical molecules using a speech based presentation. Molecular structures are typically presented as two dimensional schematics, and are an important example of a widely used form of diagram -the graph. Kekulé is designed for exploring this specific class of graph. Among its features is the ability to recognise and make explicit features of the graph that would otherwise need to be inferred. The evaluation compared Kekulé with a simpler version without this facility, and found that participants were able to explore molecular structures more easily. We discuss the software, evaluation and results, particularly comparing them with theoretical considerations about how sighted readers use diagrams. Finally, we extract the important issues for non-visual graph presentation: making implicit features explicit; enabling hierarchical and connection-based browsing; allowing annotation; and helping users keep their orientation.

One aspect of non-visual visualisation is providing accessibility to diagrams for users with visu... more One aspect of non-visual visualisation is providing accessibility to diagrams for users with visual impairments. In this paper we review the literature on diagrams and nonvisual presentation in order to elucidate the issues involved in making graph based diagrams accessible using speech and non-speech sound. First we examine the nature, scope and uses of these diagrams. We then describe the nature of diagrams: how do diagrams differ from other representations; how do sighted readers read, understand, and extract information from diagrams; what cognitive processes do diagrams facilitate; and what factors affect how diagrams may be understood? After a comparison of visual with aural presentation we discuss the work presented by others in this field, particularly looking at their reasons for implementing how they do in light of our examination of visual comprehension. The paper concludes with a discussion of how these issues combine and conflict to influence requirements for interface design.

Data sets in the biological domain are often semantically complex and difficult to integrate and ... more Data sets in the biological domain are often semantically complex and difficult to integrate and visualise. Converting between the file formats required by interactive analysis tools and those used by the global databases is a costly and error prone process. This paper describes a data model designed to enable efficient rendering of and interaction with biological data, and two demonstrator applications from different fields of protein analysis that provide co-ordinated views of data held in the underlying model

BMC Bioinformatics, 2009

Motivation In the biological sciences, the need to analyse vast amounts of information has become... more Motivation In the biological sciences, the need to analyse vast amounts of information has become commonplace. Such large-scale analyses often involve drawing together data from a variety of different databases, held remotely on the internet or locally on in-house servers. Supporting these tasks are ad hoc collections of data-manipulation tools, scripting languages and visualisation software, which are often combined in arcane ways to create cumbersome systems that have been customised for a particular purpose, and are consequently not readily adaptable to other uses. For many day-to-day bioinformatics tasks, the sizes of current databases, and the scale of the analyses necessary, now demand increasing levels of automation; nevertheless, the unique experience and intuition of human researchers is still required to interpret the end results in any meaningful biological way. Putting humans in the loop requires tools to support real-time interaction with these vast and complex data-sets. Numerous tools do exist for this purpose, but many do not have optimal interfaces, most are effectively isolated from other tools and databases owing to incompatible data formats, and many have limited real-time performance when applied to realistically large data-sets: much of the user's cognitive capacity is therefore focused on controlling the software and manipulating esoteric file formats rather than on performing the research. Methods To confront these issues, harnessing expertise in human-computer interaction (HCI), high-performance rendering and distributed systems, and guided by bioinformaticians and end-user biologists, we are building reusable software components that, together, create a toolkit that is both architecturally sound from a computing point of view, and addresses both user and developer requirements. Key to the system's usability is its direct exploitation of semantics, which, crucially, gives individual components knowledge of their own functionality and allows them to interoperate seamlessly, removing many of the existing barriers and bottlenecks from standard bioinformatics tasks. Results The toolkit, named Utopia, is freely available from http://utopia.cs.man.ac.uk/.

In silico experiments have hitherto required ad hoc collections of scripts and programs to proces... more In silico experiments have hitherto required ad hoc collections of scripts and programs to process and visualise biological data, consuming substantial amounts of time and effort to build, and leading to tools that are difficult to use, are architecturally fragile and scale poorly. With examples of the systems applied to real biological problems, we describe two complimentary software frameworks that address this problem in a principled manner; textrmsmallmy^{\textrm{\small{my}}}textrmsmallmy Grid Taverna, a workflow design and enactment environment enabling coherent experiments to be built, and UTOPIA, a flexible visualisation system to aid in examining experimental results.

This paper examines the use of audio glances for giving an impression of the size, complexity and... more This paper examines the use of audio glances for giving an impression of the size, complexity and topology of abstract graphs. The first step in nearly all reading tasks, but particularly those of complex structured information such as equations, tables and diagrams, is a glance. This brief high-level overview of the information allows the reader to start to understand the nature of his task, and to develop strategies for reading. Yet a glance is currently unavailable to visually impaired readers. We describe an algorithm for generating earcons that present such glances through non-speech sound. An evaluation demonstrated that these were successful in conveying an impression of a graph to sighted volunteers. The success of this evaluation means visually impaired readers can now start their graph-based tasks with some of the benefits a glance can bring.

Journal of Experimental Psychology-applied, 2003

The authors investigated the extent to which route learning in a virtual environment (VE) transfe... more The authors investigated the extent to which route learning in a virtual environment (VE) transfers to the real world. In Experiment 1, active VE exploration, on its own or with a map, produced better transfer of training than either no VE training at all or passive VE training; however, transfer was achieved after shorter training times with the map. Experiment 2 demonstrated that VE + map training was not superior to training with a map alone, and Experiment 3 demonstrated that the poorer performances observed after passive VE training were not simply due to a lack of attention but to the lack of active navigational decisions. The authors concluded that the present VE technology does not provide better route learning than studying a map.

Ergonomics, 2002

Three experiments compared the performances of adult participants (three groups of 10) on a perce... more Three experiments compared the performances of adult participants (three groups of 10) on a perceptuo-motor task in both real world (RW) and virtual environments (VEs). The task involved passing a hoop over a bent wire course, and three versions of the task were used: a 3-D wire course with no background, a flattened version of the 3-D course (2(1/2)-D course) with no background, and the 2(1/2)-D course with added background to provide spatial context. In all three experiments the participants had to prevent the hoop from touching the wire as they moved it. In the first experiment, the VE condition produced about 18 times more errors than the RW task. The VE 2(1/2)-D task was found to be as difficult as the 3-D, and the 2(1/2)-D with the added background produced more errors than the other two experiments. Taken together, the experiments demonstrate the difficulty of performing fine motor tasks in VEs, a phenomenon that has not been given due attention in many previous studies of motor control in VEs.

Contemporary Virtual Environments (VEs) are often graphically very sophisticated, yet although th... more Contemporary Virtual Environments (VEs) are often graphically very sophisticated, yet although their visual appearance may approach that of our real world, their apparent complexity is largely illusory. In the real world even quite simple environments offer huge scope for interaction: they consist of myriad separate objects, each of which can be manipulated and inspected, exhibit some degree of behaviour, and can have complex interactions with other objects. In its VE counterpart, most of this apparent detail turns out to be part of a texture map; commonly only a handful of objects are "real" and only a limited range of behaviour, or possibilities for interaction, are associated with them.

Concurrency and Computation: Practice and Experience, 2007

Many scientific phenomena in large high-resolution datasets such as the U.K. Ocean Circulation an... more Many scientific phenomena in large high-resolution datasets such as the U.K. Ocean Circulation and Advanced Modelling (OCCAM) ocean model are better discovered through visualization than by algorithmic analysis: it is often more straightforward to see a feature than it is to characterize it numerically. Using traditional rendering techniques, the size of modern datasets presents a challenge for even high-end graphical supercomputers, and the cost of such hardware limits its availability for day-to-day analysis. We present an architecture that brings visual analysis to the desktop by exploiting consumer-grade graphics hardware in order to provide initial interactive exploration and Web services to enable finer-grained analysis and interoperability with traditional visualization tools. Copyright © 2006 John Wiley & Sons, Ltd.

Bioinformatics/computer Applications in The Biosciences, 2009

The EMBRACE Registry is a web portal that collects and monitors web services according to test sc... more The EMBRACE Registry is a web portal that collects and monitors web services according to test scripts provided by the their administrators. Users are able to search for, rank and annotate services, enabling them to select the most appropriate working service for inclusion in their bioinformatics analysis tasks. Availability and Implementation: Website implemented with PHP, Python, MySQL and Apache, with all major browsers supported. (www.embraceregistry.net) Contact: steve.pettifer@manchester.ac.uk

This paper argues that the development of virtual actor technology must be guided by application ... more This paper argues that the development of virtual actor technology must be guided by application and end user needs. Two objectives drive the development of the 'Senet' project described in this paper: to develop a set of design guidelines for the use of virtual actors in Collaborative Virtual Environments (CVEs) for learning, and to inform the development of the underlying virtual actor technology following a user centred approach. The methodological approach followed involves the development of prototype virtual learning environments in a series of distinct phases. These are based on an ancient Egyptian game (senet) and are aimed at children at Key Stage Level 2 of the National Curriculum for education in England. Two-dimensional multimedia technology has been used to develop robust prototypes, which were then observed in use by children. The result of this study derived a set of design guidelines, which were then used to guide the implementation of a 3D CVE using the Deva CVE technology.

IEEE Transactions on Visualization and Computer Graphics, 2006

Network architectures for collaborative virtual reality have traditionally been dominated by clie... more Network architectures for collaborative virtual reality have traditionally been dominated by client-server and peerto-peer approaches, with peer-to-peer strategies typically being favoured where minimising latency is a priority, and client-server where consistency is key.

One of the challenges facing developers of large-scale and content-rich Collaborative Virtual Env... more One of the challenges facing developers of large-scale and content-rich Collaborative Virtual Environments is the lack of bandwidth to support the exchange of information between participants. It is usually not feasible for all participants to receive all the data produced by all other participants. It is therefore necessary to filter out some of such data for every user according to their interest. This paper presents an interest management mechanism based on each user's visibility of others. Its main features include occlusion awareness and visibility-based filtering, no need for a server and renderer-based visibility calculation.

As shared virtual environments move beyond mere exemplars of computer graphics techniques, and ev... more As shared virtual environments move beyond mere exemplars of computer graphics techniques, and evolve more meaningful content, issues such as 'ownership' or 'access' become important. Some artefacts in synthetic environments have 'real world' counterparts and require 'real world' access control and security. Others are entirely synthetic, and may require more esoteric access control. In either case, support for access model definition is becoming an important consideration for the future of virtual environments. In this paper we explore the different types of access required by different styles of VE, and develop a novel access model appropriate for these situations

Teleoperators and Virtual Environments, 2001

This paper describes a publicly available virtual reality (VR) system, GNU/MAVERIK, which forms o... more This paper describes a publicly available virtual reality (VR) system, GNU/MAVERIK, which forms one component of a complete VR operating system. We give an overview of the architecture of MAVERIK, and show how it is designed to use application data in an intelligent way, via a simple, yet powerful, callback mechanism that supports an object-oriented framework of classes, objects, and methods. Examples are given to illustrate different uses of the system and typical performance levels.