One of the most popular concepts within the research community at present is that of Convergence, in this case the blending of the Information Technology, Telecommunications and Entertainment Industries into a new media paradigm. In order to achieve its full potential, it will be necessary to think beyond our present media models. This will enable us to release our often unconscious commitment to the patterns that we have always known, and to look instead at the patterns that are already beginning to emerge among the next generation of users themselves.
Developments in such areas as telepresence, real-time computer imaging and advanced network capabilities are all progressing rapidly. What has been lacking however, is a clear overall vision of how all of this technological momentum might be successfully harnessed by the user community itself, to achieve the true paradigm breakthrough that Convergence has been anticipating for some time. At Cambridge University's Centre for Communications Systems Research, (CCSR), we intend to address this need. We will exploit these technological developments in order to devise new systems that will directly empower individuals, allowing them to make use of their own innate creativity by casting them in active roles within unique shared dramatic experiences.
Through such systems, everything from drama through education could potentially be transformed.
Over the past 5 years two complementary de facto standards have emerged for platform-independent dissemination of electronic documents. One of these, HTML, underpins Web browsers and has the beginnings of a structure-based approach. However. current HTML browsers are weak on the details of `appearance': they do not have an agreed notation for vector graphics and have to resort to GIF or JPEG bitmaps for all non-textual material.
By contrast, Adobe's, page-based, Portable Document Format (PDF), which is the format underlying the Acrobat viewers, is strong on `appearance', because of its PostScript-based imaging model, but very weak on any notion of document structure.
The seminar describes work under way at Nottingham, sponsored by Adobe Systems Inc., to bring the worlds of HTML and PDF closer together. A twin-track approach has been adopted of adding better graphical facilities to Web browsers while simultaneously working towards the embedding of hidden structure tags within PDF.
The first half of the talk covers the PGML and VML proposals for Web vector graphics (now subsumed into the Web Consortium's Scalable Vector Graphics -- SVG -- working group) and includes a demonstration of a prototype PGML plugin for a Web browser. The second half concentrates on the problems of PDF -> HTML -> PDF `round tripping', given that PDF is not necessarily rasterised in reading order. By embedding structural markers in PDF which demarcate features such as headings and paragraphs, together with marked-content pointers to set out the framework for reading order, it is possible to reduce greatly the `impedance mismatch' between HTML and PDF.
The recent synthesis of quantam physics with computer science has led to a new paradigm for computation which is in principle physically realisable, yet not fully encompassed by the standard (e.g. Turing) notion of computability. A quantum computer cannot compute any non-Turing-computable but it appears to be able to perform some computations exponentially faster than any classical device. The pre-eminent example is the existence of a polynomial-time quantum algorithm for integer factorisation - a problem for which there is no known classical (even randomised) efficient algorithm. In recent developments, quantum physics also gives rise to new modes of communication and an associated quantum information theory.
In this talk I will introduce the essential principles of quantum computation and outline the structure of some fundamental quantum algorithms. I will discuss the relation of quantum computation to various classical complexity classes and finally consider some recent issues of current interest.
The aim of the KRAFT (Knowledge Reuse And Fusion/Transformation) consortium (Aberdeen, BT, Cardiff and Liverpool) is to design and build a distributed system based on intelligent mediators that can transform knowledge to make it useable by problem-solvers at various sites on the network. In particular, the project is investigating how Distributed Information System architectures can support the transformation and reuse of constraints.
The DARPA-funded Knowledge Sharing Effort (KSE) (Neches et al, 1991) explored general kinds of common-sense knowledge and natural language applications. We wish to look more specifically at those kinds of knowledge that can be represented declaratively as constraints, and then transformed in ways suitable for use in design, scheduling, knowledge integration, and other applications.
The KRAFT architecture is based on agents. KRAFT agents pass around structured data items representing entity instances, defined according to an extensible data model schema. A big difference from other agent-based systems is that the agents can also pass constraints as data, where a constraint is a declarative form of predicate which can compute using functions. Constraints are effectively recipes for selecting or calculating things; they can be passed between agents, and may then be fused together or transformed into new recipes. This is the heart of the KRAFT architecture. It opens up lots of possibilities.
One obvious area of application is in configuration problems. Traditionally such problems are solved by special constraint programmes that take their parameter values from flat files prepared to specify the configuration. The KRAFT architecture generalises this to allow parameters and constraints to be discovered and brought together within a network of nodes that may develop in unanticipated ways. This makes it easier to use constraint satisfaction techniques for solving manufacturing design problems in cases where design information is distributed over a changing network.