A Survey on Continuous Time Computations

We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature

Two Decades of Maude

This paper is a tribute to José Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Non-classical computing: feasible versus infeasible

Physics sets certain limits on what is and is not computable. These limits are very far from having been reached by current technologies. Whilst proposals for hypercomputation are almost certainly infeasible, there are a number of non classical approaches that do hold considerable promise. There are a range of possible architectures that could be implemented on silicon that are distinctly different from the von Neumann model. Beyond this, quantum simulators, which are the quantum equivalent of analogue computers, may be constructable in the near future

Differences in intention to use educational RSS feeds between Lebanese and British students: A multi‑group analysis based on the technology acceptance model

Really Simple Syndication (RSS) offers a means for university students to receive timely updates from virtual learning environments. However, despite its utility, only 21% of home students surveyed at a university in Lebanon claim to have ever used the technology. To investigate whether national culture could be an influence on intention to use RSS, the survey was extended to British students in the UK. Using the Technology Adoption Model (TAM) as a research framework, 437 students responded to a questionnaire containing four constructs: behavioral intention to use; attitude towards benefit; perceived usefulness; and perceived ease of use. Principle components analysis and structural equation modelling were used to explore the psychometric qualities and utility of TAM in both contexts. The results show that adoption was significantly higher, but also modest, in the British context at 36%. Configural and metric invariance were fully supported, while scalar and factorial invariance were partially supported. Further analysis shows significant differences between perceived usefulness and perceived ease of use across the two contexts studied. Therefore, it is recommended that faculty demonstrate to students how educational RSS feeds can be used effectively to increase awareness and emphasize usefulness in both contexts

Bitcoin: the wrong implementation of the right idea at the right time

This paper is a study into some of the regulatory implications of cryptocurrencies using the CAMPO research framework (Context, Actors, Methods, Methods, Practice, Outcomes). We explain in CAMPO format why virtual currencies are of interest, how self-regulation has failed, and what useful lessons can be learned. We are hopeful that the full paper will produce useful and semi-permanent findings into the usefulness of virtual currencies in general, block chains as a means of mining currency, and the profundity of current ‘media darling’ currency Bitcoin as compared with the development of block chain generator Ethereum. While virtual currencies can play a role in creating better trading conditions in virtual communities, despite the risks of non-sovereign issuance and therefore only regulation by code (Brown/Marsden 2013), the methodology used poses significant challenges to researching this ‘community’, if BitCoin can even be said to have created a single community, as opposed to enabling an alternate method of exchange for potentially all virtual community transactions. First, BitCoin users have transparency of ownership but anonymity in many transactions, necessary for libertarians or outright criminals in such illicit markets as #SilkRoad. Studying community dynamics is therefore made much more difficult than even such pseudonymous or avatar based communities as Habbo Hotel, World of Warcraft or SecondLife. The ethical implications of studying such communities raise similar problems as those of Tor, Anonymous, Lulzsec and other anonymous hacker communities. Second, the journalistic accounts of BitCoin markets are subject to sensationalism, hype and inaccuracy, even more so than in the earlier hype cycle for SecondLife, exacerbated by the first issue of anonymity. Third, the virtual currency area is subject to slowly emerging regulation by financial authorities and police forces, which appears to be driving much of the early adopter community ‘underground’. Thus, the community in 2016 may not bear much resemblance to that in 2012. Fourth, there has been relatively little academic empirical study of the community, or indeed of virtual currencies in general, until relatively recently. Fifth, the dynamism of the virtual currency environment in the face of the deepening mistrust of the financial system after the 2008 crisis is such that any research conclusions must by their nature be provisional and transient. All these challenges, particularly the final three, also raise the motivation for research – an alternative financial system which is separated from the real-world sovereign and which can use code regulation with limited enforcement from offline policing, both returns the study to the libertarian self-regulated environment of early 1990s MUDs, and offers a tantalising prospect of a tool to evade the perils of ‘private profit, socialized risk’ which existing large financial institutions created in the 2008-12 disaster. The need for further research into virtual currencies based on blockchain mining, and for their usage by virtual communities, is thus pressing and should motivate researchers to solve the many problems in methodology for exploring such an environment

Legal Information and the Development of American Law: Writings on the Form and Structure of the Published Law

Robert C. Berring\u27s writings about the impacts of electronic databases, the Internet, and other communications technologies on legal research and practice are an essential part of a larger literature that explores the ways in which the forms and structures of published legal information have influenced how American lawyers think about the law. This paper reviews Berring\u27s writings, along with those of other writers concerned with these questions, focusing on the implications of Berring\u27s idea that in the late nineteenth century American legal publishers created a conceptual universe of thinkable thoughts through which U.S. lawyers came to view the law. It concludes that, spurred by Berring and others, the literature of legal information has become far reaching in scope and interdisciplinary in approach, while the themes struck in Berring\u27s work continue to inform the scholarship of newer writers

Modelling Cell Cycle using Different Levels of Representation

Understanding the behaviour of biological systems requires a complex setting of in vitro and in vivo experiments, which attracts high costs in terms of time and resources. The use of mathematical models allows researchers to perform computerised simulations of biological systems, which are called in silico experiments, to attain important insights and predictions about the system behaviour with a considerably lower cost. Computer visualisation is an important part of this approach, since it provides a realistic representation of the system behaviour. We define a formal methodology to model biological systems using different levels of representation: a purely formal representation, which we call molecular level, models the biochemical dynamics of the system; visualisation-oriented representations, which we call visual levels, provide views of the biological system at a higher level of organisation and are equipped with the necessary spatial information to generate the appropriate visualisation. We choose Spatial CLS, a formal language belonging to the class of Calculi of Looping Sequences, as the formalism for modelling all representation levels. We illustrate our approach using the budding yeast cell cycle as a case study

Can a computer be "pushed" to perform faster-than-light?

We propose to "boost" the speed of communication and computation by immersing the computing environment into a medium whose index of refraction is smaller than one, thereby trespassing the speed-of-light barrier.Comment: 7 pages, 1 figure, presented at the UC10 Hypercomputation Workshop "HyperNet 10" at The University of Tokyo on June 22, 201