Point regular groups of automorphisms of generalised quadrangles

We study the point regular groups of automorphisms of some of the known generalised quadrangles. In particular we determine all point regular groups of automorphisms of the thick classical generalised quadrangles. We also construct point regular groups of automorphisms of the generalised quadrangle of order $(q-1,q+1)$ obtained by Payne derivation from the classical symplectic quadrangle $\mathsf{W}(3,q)$. For $q=p^f$ with $f\geq 2$ we obtain at least two nonisomorphic groups when $p\geq 5$ and at least three nonisomorphic groups when $p=2$ or $3$. Our groups include nonabelian 2-groups, groups of exponent 9 and nonspecial $p$-groups. We also enumerate all point regular groups of automorphisms of some small generalised quadrangles.Comment: some minor changes (including to title) after referee's comment

A geometric construction of Mathon's perp-system from four lines of PG(5,3)

We give a new construction of the Mathon perp-system of the five dimensional projective space over the field with three elements, starting from four lines

Co-presence Communities: Using pervasive computing to support weak social networks

Although the strongest social relationships feature most prominently in our lives, we also maintain a multitude of much weaker connections: the distant colleagues that we share a coffee with in the afternoon; the waitress at a our regular sandwich bar; or the ‘familiar stranger’ we meet each morning on the way to work. These are all examples of weak relationships which have a strong spatial-temporal component but with few support systems available. This paper explores the idea of ‘Co-presence Communities’ - a probabilistic definition of groups that are regularly collocated together - and how they might be used to support weak social networks. An algorithm is presented for mining the Copresence Community definitions from data collected by Bluetooth-enabled mobile phones. Finally, an example application is introduced which utilises these communities for disseminating information

A Semantic Framework for Priority-based Service Matching in Pervasive Environments

The increasing popularity of personal wireless devices has raised new demands for the efficient discovery of heterogeneous devices and services in pervasive environments. The existing approaches such as Jini [1], UPnP [8], etc., describe services at a syntactic level and the matching mechanisms in these approaches are limited to syntactic comparisons based on attributes or interfaces. In order to overcome the limitations in these approaches, there has been an increased interest in the use of semantic description and matching techniques to support effective service discovery. This paper proposes a semantic matching approach which facilitates the discovery of device-based services in a pervasive environment; the approach provides a ranking facility that orders services according to their suitability and also considers priorities placed on individual requirements in a request during the matching process. The evaluation studies have shown that the matcher results correlate reasonably well with human judgement

A Semantic Approach for Description and Ranked Matching of Services in Pervasive Environments

With the recent developments in technology, new and diverse devices are being introduced into the pervasive world. This has raised new challenges for the discovery of devices and their services in dynamic environments. The existing approaches such as Jini [AOSJ99], UPnP [UPnP06], etc., describe services at a syntactic level and the matching mechanisms in these approaches are limited to syntactic comparisons based on attributes or interfaces. In order to overcome the limitations of these approaches, there has been an increasing interest in the use of Semantic Web technologies to support the description and matching of services. This paper proposes a semantic matching framework to facilitate effective discovery of device based services in pervasive environments. This offers a ranking mechanism that will order the available services in the order of their suitability; the evaluation of the experimental results have indicated that the results correlate well with human perception

Patients' preferences for the management of non-metastatic prostate cancer: discrete choice experiment

Objective To establish which attributes of conservative treatments for prostate cancer are most important to men. Design Discrete choice experiment. Setting Two London hospitals. Participants 129 men with non-metastatic prostate cancer, mean age 70 years; 69 of 118 (58%) with T stage 1 or 2 cancer at diagnosis. Main outcome measures Men's preferences for, and trade-offs between, the attributes of diarrhoea, hot flushes, ability to maintain an erection, breast swelling or tenderness, physical energy, sex drive, life expectancy, and out of pocket expenses. Results The men's responses to changes in attributes were all statistically significant. When asked to assume a starting life expectancy of five years, the men were willing to make trade-offs between life expectancy and side effects. On average, they were most willing to give up life expectancy to avoid limitations in physical energy (mean three months) and least willing to trade life expectancy to avoid hot flushes (mean 0.6 months to move from a moderate to mild level or from mild to none). Conclusions Men with prostate cancer are willing to participate in a relatively complex exercise that weighs up the advantages and disadvantages of various conservative treatments for their condition. They were willing to trade off some life expectancy to be relieved of the burden of troublesome side effects such as limitations in physical energy

A Pragmatic Approach for the Semantic Description and Matching of Pervasive Resources

The increasing popularity of personal wireless devices has raised new demands for the efficient discovery of heterogeneous devices and services in pervasive environments. With the advancement of the electronic world, the diversity of available services is increasing rapidly. %This raises new demands for the efficient discovery and location of heterogeneous services and resources in dynamically changing environments. Traditional approaches for service discovery describe services at a syntactic level and the matching mechanisms available for these approaches are limited to syntactic comparisons based on attributes or interfaces. In order to overcome these limitations, there has been an increased interest in the use of semantic description and matching techniques to support effective service discovery. In this paper, we present a semantic matching approach to facilitate the discovery of device-based services in pervasive environments. The approach includes a ranking mechanism that orders services according to their suitability and also considers priorities placed on individual requirements in a request during the matching process. The solution has been systematically evaluated for its retrieval effectiveness and the results have shown that the matcher results agree reasonably well with human judgement. Another important practical concern is the efficiency and the scalability of the semantic matching solution. Therefore, we have evaluated the scalability of the proposed solution by investigating the variation in matching time in response to increasing numbers of advertisements and increasing request sizes, and have presented the empirical results

Intriguing sets of partial quadrangles

The point-line geometry known as a \textit{partial quadrangle} (introduced by Cameron in 1975) has the property that for every point/line non-incident pair $(P,\ell)$, there is at most one line through $P$ concurrent with $\ell$. So in particular, the well-studied objects known as \textit{generalised quadrangles} are each partial quadrangles. An \textit{intriguing set} of a generalised quadrangle is a set of points which induces an equitable partition of size two of the underlying strongly regular graph. We extend the theory of intriguing sets of generalised quadrangles by Bamberg, Law and Penttila to partial quadrangles, which surprisingly gives insight into the structure of hemisystems and other intriguing sets of generalised quadrangles

Testate amoebae as a proxy for reconstructing Holocene water table dynamics in southern Patagonian peat bogs

Funded by Natural Environment Research Council. Grant Numbers: NE/I022809/1, NE/I022981/1, NE/I022833/1, NE/I023104/1 Ricardo Muza and the Wildlife Conservation Society Karukinka Park Acknowledgements This work was supported by the Natural Environment Research Council (grant numbers NE/I022809/1, NE/I022981/1, NE/I022833/1 and NE/I023104/1). We thank Ricardo Muza and the Wildlife Conservation Society (WCS) Karukinka Park rangers for facilitating access to Karukinka Park. We also thank François De Vleeschouwer, Gaël Le Roux, Heleen Vanneste, Sébastien Bertrand, Zakaria Ghazoui and Jean-Yves De Vleeschouwer for fieldwork assistance. Nelson Bahamonde (INIA, Punta Arenas, Chile) and Ernesto Teneb (UMag, Punta Arenas, Chile) provided logistical support for the fieldwork in Chile. Dr Andrea Coronato (CADIC, Ushuaia) kindly provided logistical support for the research in Argentina. Thanks to Jenny Johnston for cartography, David Jolley for assistance in microscopic photography and Audrey Innes for laboratory assistance. We highly appreciate reviews by Matt Amesbury and an anonymous reviewer. R.P. is supported by an Impact Fellowship from the University of Stirling.Peer reviewedPublisher PD