## About

92

Publications

19,453

Reads

**How we measure 'reads'**

A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more

1,734

Citations

Citations since 2016

## Publications

Publications (92)

The expansion and contraction are the fundamental operations in systems assigning resources strictly based on load.
Previously, an aggregation algorithm was proposed for distributing the load of a space (square in shape initially) comprises of a number of sub-spaces as balanced as possible among two servers.
It used the SplitCapacity constraint to...

OpenSimulator has emerged as one of the leading tools to help researchers, developers, and practitioners working in the field of virtual worlds since it is an open-source alternative to second life, the state of the art in virtual worlds. The grid mode of OpenSimulator is highly scalable, and it places no restriction on the number of cooperating Op...

OpenSimulator, when configured in grid mode, is highly scalable and places no restriction on the number of running OpenSimulator instances, often called Simulator, or the number of regions assigned to a simulator. However, the current implementation employs static configuration which either results in under-use of resources or restricts system capa...

This paper reports on the development of a system that translates German train announcements of the Swiss Federal Railways (Schweizerische Bundesbahnen, SBB) into Swiss German Sign Language (Deutschschweizerische Gebärdensprache, DSGS) in real time and displays the result via an avatar. The system used to animate the avatar is called JASigning. Del...

We are building a system that translates German train announcements of the Swiss Federal Railways (Schweizerische Bundesbahnen, SBB) into Swiss German Sign Language (Deutschschweizerische Gebärdensprache, DSGS) in real time and displays the result via an avatar. We use the JASigning system to animate the avatar. Deliverables of the projects during...

The paper provides a report on the user-centred showcase prototypes of the DICTA-SIGN project (http://www.dictasign.eu/), an FP7-ICT project which ended in January 2012. DICTA-SIGN researched ways to enable communication between Deaf individuals through the development of human-computer interfaces (HCI) for Deaf users, by means of Sign Language. Em...

Here we present the outcomes of Dicta-Sign FP7-ICT project. Dicta-Sign researched ways to enable communication between Deaf
individuals through the development of human-computer interfaces (HCI) for Deaf users, by means of Sign Language. It has
researched and developed recognition and synthesis engines for sign languages (SLs) that have brought sig...

This paper presents the multilingual corpus of four European sign languages compiled in the framework of the Dicta-Sign project. Dicta-Sign researched ways to enable communication between Deaf individuals through the development of human-computer interfaces (HCI) for Deaf users, by means of sign language. Sign language resources were compiled to in...

We describe a prototype Search-by-Example or look-up tool
for signs, based on a newly developed 1000-concept sign
lexicon for four national sign languages (GSL, DGS, LSF,
BSL), which includes a spoken language gloss, a HamNoSys
description, and a video for each sign. The look-up tool
combines an interactive sign recognition system, supported
by Kin...

We present a small-scale study that provides detailed timing information for individual sign parameters in natural signing with a time resolution of 1/50 of a second as well as the method and tools used to collect these data. The avatar system was improved to be able to play back signing annotated in a combination of symbolic movement description a...

virtual space. Whenever, a server exceeds its maximum capacity, a new server is added and the load is shared with it. This extension also incorporates a consistency model based on a constrained communication modeL The proposed extension maintains resources in a hierarchy and uses a decentralised approach for consistency management based on our prev...

In this paper the potential of combining low cost systems with technologies for modelling and rendering populated urban scenes and multilingual interactive avatars is presented. As an example, a medieval European city was recreated, such that within this virtual environment, visitors can see for themselves how buildings look and hear from a multili...

Describes how a multilingual corpus is used to improve sign language technology

Time Management (TM) is an integral part of the parallel and distributed systems that maintains the temporal order of events in a system. In this paper, we present a decentralised TM approach using a constrained communication model based on the inherent properties of virtual worlds. The proposed method uses a flat communication model and a region s...

The introduction of modern communication and computation technologies has greatly changed the traditional approaches processing computationally intensive applications such as Virtual Environments (VEs). Distributed and multi-server architectures are scalable and exploit the concepts of spatial and temporal locality for handling massive Distributed...

Sign language and Web 2.0 applications are currently incompatible, because of the lack of anonymisation and easy editing of online sign language contributions. This paper describes Dicta-Sign, a project aimed at developing the technologies required for making sign language-based Web contributions possible, by providing an integrated framework for s...

We outline the main features of our synthetic virtual human sign language system, JASigning. We describe how we have extended its input notation, SiGML, to allow explicit control of performance time, and we describe our initial steps on the path to integrating virtual human sign language performance into annotation tools, where it may be compared w...

Splitting and executing different parts of a system with the
help of a set of dedicated servers is the most widely used
technique for making it scalable. However, it introduces
synchronisation issues and requires special attention. Syn
chronisation is extensively investigated for parallel and dis
tributed systems and generally centralised or distri...

Scalability and consistency are fundamental issues to deal with in large scale distributed virtual environments (DVEs). To make a VE scalable, it is usually partitioned into a number of regions and processed by a set of dedicated servers. Static configurations are unable to handle dynamic load, and therefore, dynamic strategies are widely investiga...

Sign language and Web 2.0 applications are currently incompatible, because of the lack of anonymisation and easy editing of
online sign language contributions. This paper describes Dicta-Sign, a project aimed at developing the technologies required
for making sign language-based Web contributions possible, by providing an integrated framework for s...

Virtual Environments (VEs) have recently gained a lot of attention from the Computing, Graphics, Business and Social communities due to a remarkable increase in their popularity. These communities are working together to make these environments more sociable and interesting while introducing novel applications. A number of technical infrastructures...

Sign languages are the native languages for many pre-lingually deaf people and must be treated as genuine natural languages
worthy of academic study in their own right. For such pre-lingually deaf, whose familiarity with their local spoken language
is that of a second language learner, written text is much less useful than is commonly thought. This...

Written information is often of limited accessibility to deaf people who use sign language. The eSign project was undertaken as a response to the need for technologies enabling efficient production and distribution over the Internet of sign language content. By using an avatar-independent scripting notation for signing gestures and a client-side we...

Of the many proposals for parallel computer architectures, dataflow systems offer perhaps the greatest potential parallelism
at the hardware level. However, it is unreasonable to expect users to exploit this parallelism at such a low level, and it
is necessary to provide high level programming facilities which allow the user the abstract freedom of...

Although the advantages of the use of 3D Immersive Virtual Environments for the presentation and communica- tion of Cultural Heritage have been demonstrated, the user interfaces and interaction techniques (in software and hardware) that are best suited have not yet been completely identified and deployed. This paper describes research conducted for...

This is a conference paper. Approximately 50,000 people in the UK, mostly those born deaf, use British Sign Language (BSL) as their first or preferred language (RNID, 2007). The Disability Discrimination Act puts new responsibilities onto examination boards to ensure adequate access for all candidates, however we are aware of ongoing issues and lim...

We describe an event-style (or poset) semantics for conflict-free rewrite systems, such as the -calculus, and other stable transition systems with a residual relation. Our interpretation is based on considering redex families as events. It treats permutation-equivalent reductions as representing the same concurrent computation. Due to erasure of re...

Dactl is an experimental language programming language based on fine grain graph transformations. It was developed in the context of a large parallel reduction machine project. The design of the language is outlined, and examples given of its use both as a compiler target language and as a programming language. Dactl has a formal semantics and stab...

We study reductions in orthogonal (left-linear and non-ambiguous) Expression Reduction Systems, a formalism for Term Rewriting Systems with bound variables and substitutions. To generalise the normalization theory of Huet and Lvy, we introduce the notion of neededness with respect to a set of reductions S\mathcal{S}
so that each existing notion of...

This paper generalizes the Huet and Lvy theory of normalization by neededness to an abstract setting. We define Stable Deterministic Residual Structures (SDRS) and Deterministic Family Structures (DFS) by axiomatizing some properties of the residual relation and the family relation on redexes in an Abstract Rewriting System. We present two proofs o...

Graph rewriting (also called reduction) as defined in Wadsworth [1971] was introduced in order to be able to give a more efficient implementation of functional programming languages in the form of lambda calculus or term rewrite systems: identical subterms are shared using pointers.
Several other authors, e.g. Ehrig [1979], Staples [1980a,b,c], Rao...

Lean is an experimental language for specifying computations in terms of graph rewriting. It is based on an alternative to Term Rewriting Systems (TRS) in which the terms are replaced by graphs. Such a Graph Rewriting System (GRS) consists of a set of graph rewrite rules which specify how a graph may be rewritten. Besides supporting functional prog...

We investigate mutual dependencies of subexpressions of computable expressions in orthogonal rewrite systems, and identify conditions for their independent concurrent computation. To this end, we introduce concepts familiar from ordinary Euclidean Geometry (such as basis, projection, distance, etc.) for reduction spaces. We show how a basis at an e...

Expression Reduction Systems is a formalism for higher-order rewriting, extending Term Rewriting Systems and the lambda-calculus.
Here we give an overview of results in the literature concerning ERSs. We review confluence, normalization and perpetuality
results for orthogonal ERSs. Some of these results are extended to orthogonal conditional ERSs....

We present an overview of research at UEA into the animation of sign language using a gesture notation, outlining applications that have been developed and key aspects of the implementation. We argue that the requirements for virtual human signing involve the development of expressive characters. Although the prin- cipal focus of work has been on s...

In previous works, we introduced Stable Deterministic Residual Structures (SDRSs), Abstract Reduction Systems with an axiomatized residual relation which model orthogonal term and graph rewriting systems, and Deterministic Family Structures (DFSs), which add an axiomatized notion of redex-family to capture known sharing concepts in the λ-calculus a...

We study orderings £S on reductions in the style of Levy re∞ecting the growth of information w.r.t. (super)stable sets S of 'val- ues' (such as head-normal forms or Bohm-trees). We show that sets of co-initial reductions ordered by £S form flnitary !-algebraic complete lattices, and hence form computation and Scott domains. As a conse- quence, we o...

The drawbacks of programming coordination activities directly within the applica-tions software that needs them are briefly reviewed. Coordination programming helps to separate concerns, making complex coordination protocols into standalone entities; permitting separate development, verification, maintenance, and reuse. The IWIM coordination model...

Two dimensional (2D) shape and appearance models are applied to the problem of creating a near-videorealistic talking head. A speech corpus of a talker uttering a set of phonetically balanced training sentences is analysed using a generative model of the human face. Segments of original parameter trajectories corresponding to the synthesis unit (e....

We study normalization by neededness with respect to 'infinite results', such as Bohm-trees, in an abstract framework of Stable Deterministic Residual Structures. We formalize the concept of 'infinite results' for finite terms as suitable sets of infinite reductions, and prove an abstract infinitary normalization theorem with respect to such sets....

We describe an event-style (or poset) semantics for conflict-free rewrite systems, including term and graph rewriting (possibly with bound variables),the λ-calculus, and other stable transition systems with a residual relation. Our interpretation is based on considering redex-families as events. It treats permutation-equivalent reductions as repres...

Coordination programming helps to separate concerns in the programming of the coordination activities in complex applications software. It separates the development, verification, maintenance, and reuse of the coordination and communication protocols, from the development of the rest of the application; coincidentally making these entities into sta...

The drawbacks of programming coordination activities directly within the applications software that needs them are briefly reviewed. Coordination programming helps to separate concerns, making complex coordination protocols into standalone entities; permitting separate development, verification, maintenance, and reuse. The IWIM coordination model i...

Coordination programming helps to separate concerns in the programming of the coordination activities in complex applications software. It separates the development, veri cation, maintenance, and reuse of the coordination and communication protocols, from the development of the rest of the application; coincidentally making these entities into stan...

In orthogonal expression reduction systems, a common generalization of term rewriting and #-calculus, we extend the concepts of normalization and needed reduction by considering, instead of the set of normal forms, a set S of "results". When S satisfies some simple axioms, we prove the corresponding generalizations of some fundamental theorems: the...

We present an outline of the technical aspects of the recently
started ViSiCAST project, which aims to provide deaf citizens with
improved access to services and facilities through sign language. At the
core of the project are `enabling technology' workpackages, concerned
with the further development of the language technology and avatar
technology...

ViSiCAST is a major new project funded by the Euro-pean Union, aiming to provide improved access to ser-vices and facilities for deaf citizens through sign lan-guage presented by a virtual human, or avatar. We give here an outline of the project, and describe early work in the area of linguistics and language processing. This work covers two distin...

. This paper generalizes the Huet and L'evy theory of normalization by neededness to an abstract setting. We define Stable Deterministic Residual Structures (SDRS) and Deterministic Family Structures (DFS) by axiomatizing some properties of the residual relation and the family relation on redexes in an Abstract Rewriting System. We present two proo...

We investigate mutual dependencies of subexpressions of a computable expression, in orthogonal rewrite systems, and identify conditions for their independent computation, concurrently. To this end, we introduce concepts familiar from ordinary Euclidean Geometry (such as basis, projection, distance, etc.) for reduction spaces. We show how a basis at...

This paper generalizes the Huet and L'evy theory of normalization by neededness to an abstract setting. We define Stable Deterministic Residual Structures (SDRS) and Deterministic Family Structures (DFS) by axiomatizing some properties of the residual relation and the family relation on redexes in an Abstract Reduction System. We present two proofs...

We investigate mutual dependencies of subexpressions of a computable expression, in orthogonal rewrite systems, and identify conditions for their concurrent independent computation. To this end, we introduce concepts familiar from ordinary Euclidean Geometry (such as basis, projection, distance, etc.) for reduction spaces. We show how a basis for a...

. We prove a version of the Standardization Theorem and the Discrete Normalization (DN) Theorem in stable Deterministic Residual Structures, which are Abstract Reduction Systems with axiomatized residual relation, and model orthogonal rewrite systems. The latter theorem gives a strategy for construction of reductions L'evy-equivalent (or permutatio...

In a previous paper, we introduced Stable Deterministic Residual Structures (SDRSs), Abstract Reduction Systems with an axiomatized residual relation which model orthogonal term and graph rewriting systems, and Deterministic Family Structures (DFSs), which are SDRSs with an axiomatized notion of redex-family to capture known sharing concepts in the...

. In previous papers, the authors studied normalization relative to desirable sets S of `partial results', where it is shown that such sets must be stable. For example, the sets of normal forms, head-normal-forms, and weak head-normal-forms in the -calculus, are all stable. They showed that, for any stable S, S-needed reductions are S-normalizing....

Machine [Ber90] than a traditional graph reduction machine. 6 Results A translator has been developed which will convert "programs" in an extended -Calculus to the process notation. Several different translations from -Calculus to processes have been implemented. The process networks are converted to the sublanguage which makes heavy use of agent d...

Honda and Tokoro provide a formal system for communicating systems developed from Milner's π-calculus. Unlike other formalisms, their work is based on asynchronous communication primitives.
This paper proposes some minor but practically significant extensions to a model based on asynchronous communication and shows how the resulting system may be m...

sm. The promise has yet to be realised, partly through lack of acceptable implementations and programming environments, and partly due to the difficulty of coding portions of applications which do not fit naturally into a declarative style. It can be argued that serious sequential implementations are now available. Logic programmers have a number o...

. The Object Graph Rewriting (OGRe) model is an abstract machine which combines ideas from graph rewriting and process calculi. OGRe has been designed for implementing multi-paradigm languages such as Facile, which combines functional and concurrent programming. Simple objects, with state given by term structures, respond to messages, also represen...

Introduction The aim of the project was to explore the usefulness of graph rewriting as an implementation technique for multi-paradigm languages focussing mainly, but not exclusively, on declarative programming styles. The project built on experience using Extended Term Graph Rewriting [25] to implement a range of programming languages and aimed fo...

A generalized computational model based on graph rewriting is presented along with Dactl, an associated compiler target (intermediate) language. An illustration of the capability of graph rewriting to model a variety of computational formalisms is presented by showing how some examples written originally in a number of languages can be described as...

Object Graph Rewriting (OGRe) is a computational model which combines ideaa from graph rewriting and process calculi. OGRe has been designed for implementing multiparad@n languages such as Facile, which combines functional and concurrent programming. Simple objects, which have states represented by treestructured terms, respond to messages, also re...

In previous papers, the authors studied normalization relative to desirable sets S of partial results, where it is shown that such sets must be stable. For example, the sets of normal forms, head-normal-forms, and weak head-normal-forms in the -calculus, are all stable. They showed that, for any stable S, S-needed reductions are S-normalizing. This...

We report work in progress on the implementation of languages that integrate concurrent and functional programming styles. A translation scheme is presented for mapping such languages into process networks using a simple notation based on communication between named processes. The translation of functional code is sequential, but parallelism arises...

LEAN is an exaerimental language for specifying computations in terms of graph rewriting. It is based on an alternative to Term Rewriting Systems (TRS) in which the terms are replaced by graphs. Such a Graph Rewriting System (GRS) consists of a set of graph rewrite rules which specify how a graph may be rewritten. Besides supporting functional prog...

An abstract is not available.

The Alvey programme has adopted a model of computation based on Graph Reduction as a focus for UK work on New Generation Languages and Architectures. The development of this model is being undertaken by an Alvey-sponsored project at the University of East Anglia (UEA) at Norwich entitled DACTL (Declarative Alvey Compiler Target Language). Collabora...

…the design of ADA is based on an implicit
assumption of a hardware model with a single shared memory. This paper
identifies the ADA facilities influenced by this invalid assumption. It
proposes ways to overcome these weaknesses ...

Many multi-processor systems are currently under study by various groups around the world. The understanding and exploitation of parallelism in these systems is a primary goal of these studies. To facilitate the use and comparison of these systems, we proposed to define a common high-level language. The primary candidate was a single-assignment, ap...