1,721,504 research outputs found
The Ever Evolving Web: the Power of Networks
No full textIn this paper we consider the Web as a network of networks and reflect on its evolution, firstly by analyzing the reasons why it became the first truly ubiquitous hypertext system against all competitors and secondly by looking at how it has evolved from a network of linked documents to a system that facilitates social networking on a scale previously unimaginable and how it will evolve in the future as a network of linked data and beyond. The study of the Web—its evolution and its impact on society, on business and on government—is referred to as Web Science. We consider some of the major challenges of Web Science and discuss possible Web worlds of the future
Automorphisms and coverings of Klein surfaces
No full textIn this thesis the theory of automorphisms and coverings of compact Klein surfaces is discussed by considering a Klein surface as the orbit space of a non-Euclidean crystallographic group. In chapter 1 we set out some of the well-established theory concerning these ideas. In chapter 2 maximal automorphism groups of compact Klein surfaces without boundary are considered. We solve the problem of which groups PSL (2,q) act as maximal automorphism groups of non-orientable Klein surface without boundary. In chapter 3 we discuss cyclic groups acting as automorphism groups of compact Klein surfaces without boundary. It is shown that the maximum order for a cyclic group to be an automorphism group of a compact non-orientable Klein surface without boundary of genus g ?3 is 2g, if g is odd and 2 (g – 1) if g is even. Chapter 4 is the largest section of the thesis. It is concerned with coverings (possibly folded and ramified) of compact Klein surfaces, mainly Klein surfaces with boundary. All possible two-sheeted connected unramified covering surfaces of a Klein surface are classified and the orientability of a normal n-sheeted cover, for odd n, is determine
The Emerging Science of the Web and Why it is Important
No full textWith the advent of the internet and the World Wide Web we are able to share information as never before. The Web has become a critical global infrastructure. Since its emergence in the mid-1990s, it has exploded into hundreds of billions of pages that touch almost all aspects of modern life. Today the jobs of more and more people depend on the Web. Media, banking and health care are being revolutionized by it, and governments are even considering how to run their countries with it. Little appreciated, however, is the fact that the Web is more than the sum of its pages and it is more than its technical protocols. Vast emergent properties have arisen that are transforming society. E-mail led to instant messaging, which on the Web has led to social networks such as Facebook and Twitter. The transfer of documents led to file-sharing sites such as Napster, which have led to user-generated portals such as blogs, Flickr and YouTube. Web 2.0, tagging content with labels, is creating online communities that share everything from concert news to health care. Looking forward we are adding to the Web of documents by creating a Web of linked data. It is our hypothesis that this will become the dominant data sharing and integration platform and that its effect on the world will be as profound and unexpected as the impact of the first Web. As we seek to understand the origins of the Web, appreciate its current state and anticipate possible futures there is a need to address the critical questions that will determine how the Web evolves as both a social and a technical network. The emerging field of understanding these issues is becoming known as Web Science. In this talk we will explore how this new science of the Web has become established, the insights that are beginning to emerge and discuss the major research and education challenges ahead
UK Prime Minister’s Council for Science and Technology report “Better Use of Personal Information: Opportunities and Risks”
No full textRUSI report “A Democratic Licence to Operate: Report of the Independent Surveillance Review
No full textOn the expressiveness of links in hypertext systems
No full textIn this paper, we study how linking mechanisms contribute to the expressiveness of hypertext systems. For this purpose, we formalise hypertext systems as abstract machines. As the primary benefit of hypertext systems is to be able to read documents non-linearly, their expressiveness is defined in terms of the ability to follow links. Then, we classify hypertext systems according to the power of the underlying automaton. The model allow us to compare embedded vs separate links and simple vs generic links. Then, we investigate history mechanisms, adaptive hypertexts, and functional links. Our conclusion is that simple links, whether embeded or separate, generic links, and some adaptive links all give hypertext systems the power of finite state automata. The history mechanism confers them the power of pushdown automata, whereas the general functional links give them Turing completeness
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