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  • Publication . Part of book or chapter of book . Conference object . Book . 2006
    Open Access English
    Authors: 
    Arosha K. Bandara; Antonis C. Kakas; Emil Lupu; Alessandra Russo;

    Firewalls are important perimeter security mechanisms that imple-ment an organisation's network security requirements and can be notoriously difficult to configure correctly. Given their widespread use, it is crucial that network administrators have tools to translate their security requirements into firewall configuration rules and ensure that these rules are consistent with each other. In this paper we propose an approach to firewall policy specification and analysis that uses a formal framework for argumentation based preference reasoning. By allowing administrators to define network abstractions (e.g. subnets, protocols etc) security requirements can be specified in a declarative manner using high-level terms. Also it is possible to specify preferences to express the importance of one requirement over another. The use of a formal framework means that the security requirements defined can be automatically analysed for inconsistencies and firewall configurations can be automatically generated. We demonstrate that the technique allows any inconsistency property, including those identified in previous research, to be specified and automatically checked and the use of an argumentation reasoning framework provides administrators with information regarding the causes of the inconsistency.

  • Publication . Part of book or chapter of book . Conference object . 2001
    Open Access English
    Authors: 
    Christopher B. Jones; Harith Alani; Douglas Tudhope;
    Country: United Kingdom

    Geographical context is required of many information retrieval tasks in which the target of the search may be documents, images or records which are referenced to geographical space only by means of place names. Often there may be an imprecise match between the query name and the names associated with candidate sources of information. There is a need therefore for geographical information retrieval facilities that can rank the relevance of candidate information with respect to geographical closeness of place as well as semantic closeness with respect to the information of interest. Here we present an ontology of place that combines limited coordinate data with semantic and qualitative spatial relationships between places. This parsimonious model of geographical place supports maintenance of knowledge of place names that relate to extensive regions of the Earth at multiple levels of granularity. The ontology has been implemented with a semantic modelling system linking non-spatial conceptual hierarchies with the place ontology. An hierarchical spatial distance measure is combined with Euclidean distance between place centroids to create a hybrid spatial distance measure. This is integrated with thematic distance, based on classification semantics, to create an integrated semantic closeness measure that can be used for a relevance ranking of retrieved objects.

  • Publication . Part of book or chapter of book . 2015
    Open Access English
    Authors: 
    Bernadette Elliott-Bowman; Rongshan Qin;
    Publisher: TOMCK Publishing House HTO

    The influence of electropulsing on metallic materials is reviewed, with a focus on phase transformations and grain refinement. While a large and growing body of literature exists on the topic of electropulsing, the mechanisms governing the process are not currently fully understood. Furthermore, the effects of electropulsing on microstructure and mechanical properties are not yet clearly defined. This review seeks to summarise the existing literature in order to highlight and understand research trends across a variety of metals and alloys, and to clarify the state of the art. Research has shown that the electropulsing process is capable of inducing low temperature recrystallisation in metallic materials at an accelerated rate compared to more traditional heat treatment methods. These microstructural changes often alter the mechanical properties of the materials such as ductility, tensile strength and hardness. Crack healing as a result of electropulsing treatment has also been observed in damaged or work hardened materials and pre-deformation of the sample has been shown to enhance the effects of electropulsing.

  • Publication . Article . Conference object . Contribution for newspaper or weekly magazine . Part of book or chapter of book . 2016
    Open Access English
    Authors: 
    Feroci, M.; Bozzo, E.; Brandt, S.; Hernanz, M.; Van Der Klis, M.; Liu, L. P.; Orleanski, P.; Pohl, M.; Santangelo, A.; Schanne, S.; +191 more
    Countries: Netherlands, Italy, United Kingdom, France, Denmark, Italy, Italy, Turkey, Netherlands, Italy ...

    The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able to study the behaviour of matter in extreme conditions such as the strong gravitational field in the innermost regions close to black holes and neutron stars and the supra-nuclear densities in the interiors of neutron stars. The science payload is based on a Large Area Detector (LAD, >8m2 effective area, 2-30 keV, 240 eV spectral resolution, 1 degree collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g., GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the current technical and programmatic status of the mission. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  • Open Access English
    Authors: 
    Damian J. J. Farnell; Jennifer Galloway; Alexei I. Zhurov; Stephen Richmond; Pertti Pirttiniemi; Raija Lähdesmäki;
    Publisher: Springer

    Multilevel principal components analysis (mPCA) has previously been shown to provide a simple and straightforward method of forming point distribution models that can be used in (active) shape models. Here we extend the mPCA approach to model image texture as well as shape. As a test case, we consider a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Shape (in terms of landmark points) and image texture are considered separately in this initial analysis. Three-level models are constructed that contain levels for biological sex, “within-subject” variation (i.e., facial expression), and “between-subject” variation (i.e., all other sources of variation). By considering eigenvalues, we find that the order of importance as sources of variation for facial shape is: facial expression (47.5%), between-subject variations (45.1%), and then biological sex (7.4%). By contrast, the order for image texture is: between-subject variations (55.5%), facial expression (37.1%), and then biological sex (7.4%). The major modes for the facial expression level of the mPCA models clearly reflect changes in increased mouth size and increased prominence of cheeks during smiling for both shape and texture. Even subtle effects such as changes to eyes and nose shape during smile are seen clearly. The major mode for the biological sex level of the mPCA models similarly relates clearly to changes between male and female. Model fits yield “scores” for each principal component that show strong clustering for both shape and texture by biological sex and facial expression at appropriate levels of the model. We conclude that mPCA correctly decomposes sources of variation due to biological sex and facial expression (etc.) and that it provides a reliable method of forming models of both shape and image texture.

  • Open Access English
    Authors: 
    Gallardo, M.;
    Publisher: Universidad de Cadiz
  • Publication . Part of book or chapter of book . Other literature type . Conference object . 2017
    Open Access English
    Authors: 
    Damian J. J. Farnell; Jennifer Galloway; Alexei I. Zhurov; Stephen Richmond; Pertti Perttiniemi; Višnja Katić;
    Country: Croatia

    Traditionally, active shape models (ASMs) do not make a distinction between groups in the subject population and they rely on methods such as (single-level) principal components analysis (PCA). Multilevel principal components analysis (mPCA) allows one to model between- group effects and within-group effects explicitly. Three dimensional (3D) laser scans were taken from 250 subjects (38 Croatian female, 35 Croatian male, 40 English female, 40 English male, 23 Welsh female, 27 Welsh male, 23 Finnish female, and 24 Finnish male) and 21 landmark points were created subsequently for each scan. After Procrustes transformation, eigenvalues from mPCA and from single-level PCA based on these points were examined. mPCA indicated that the first two eigenvalues of largest magnitude related to within-groups components, but that the next eigenvalue of largest magnitude related to between-groups components. Eigenvalues from single-level PCA always had a larger magnitude than either within-group or between-group eigenvectors at equivalent eigenvalue number. An examination of the first mode of variation indicated possible mixing of between-group and within-group effects in single-level PCA. Component scores for mPCA indicated clustering with country and gender for the between-groups components (as expected), but not for the within-group terms (also as expected). Clustering of component scores for single-level PCA was harder to resolve. In conclusion, mPCA is viable method of forming shape models that offers distinct advantages over single-level PCA when groups occur naturally in the subject population.

  • Open Access English
    Authors: 
    Page, Susan; Rieley, Jack; Hoscilo, Agata; Spessa, Allan; Weber, Ulrich;
    Publisher: Kessel

    The Southeast Asian region is experiencing some of the world’s highest rates of deforestation and forest degradation, the principle drivers of which are agricultural expansion and wood extraction in combination with an increased incidence of fire. Recent changes in fire regimes in Southeast Asia are indicative of increased human-causd forest disturbance, but El Niño–Southern Oscillation (ENSO) events also play a role in exacerbating fire occurrence and severity. Fires are now occurring on a much more extensive scale - in part because forest margins are at greater risk of fire as a result of disturbance through logging activities, but also as a result of rapid, large-scale forest clearance for the establish-ment of plantations. Millions of hectares have been deforested and drained to make way for oil palm and pulpwood trees, and many plantation companies, particularly in Indonesia, have employed fire as a cheap land clearance tool; uncontrolled fires have entered adjacent forests or plantation estates, and burnt both the forest biomass and, in peatland areas, underlying peat. Forest fires cause changes to forest structure, biodiversity, soil and hydrology. Repeated fires over successive or every few years lead to a progressive decline in the number of primary forest species. Fire leads to reduction in both aboveground and below ground organic carbon stocks and also changes carbon cycling patterns. In non-peatland areas, losses of carbon from fire affected forest vegetation exceed greatly soil carbon losses, but on carbon-rich substrates, e.g. peat, combustion losses can be considerable. Peatland fires make a major contribution to atmospheric emissions of greenhouse gases, fine particular matter and aerosols and thus contribute to climate change as well as presenting a problem for human health. The scale of emissions is unlikely to reduce in coming decades, since climate modelling studies have predicted that parts of this region will experience lower rainfall in future and greater seasonality. Protecting the rainforests of this region from further fire disasters should be at the top of the global environmental agenda, with highest priority given to peatland areas.

  • Publication . Part of book or chapter of book . Conference object . 2005
    Open Access English
    Authors: 
    Eckert, Claudia; Stacey, Martin; Earl, Christopher;
    Publisher: Key Centre of Design Computing and Cognition
    Country: United Kingdom

    Designing by adaptation is almost invariably a dominantambiguity feature of designing, and references to past designs are ubiquitous in design discourse. Object references serve as indices into designers' stocks of design concepts, in which memories for concrete embodiments and exemplars are tightly bound to solution principles. Thinking and talking by reference to past designs serves as a way to reduce the overwhelming complexity of complex design tasks by enabling designers to use parsimonious mental representations to which details can be added as needed. However object references can be ambiguous, and import more of the past design than is intended or may be desirable.

  • Open Access English
    Authors: 
    Barker, Elton; Isaksen, Leif; Rabinowitz, Nick; Bouzarovski, Stefan; Pelling, Chris;
    Publisher: Institute of Classical Studies, University of London

    Involving the collaboration of researchers from Classics, Geography and Archaeological Computing, and supported by funding from the AHRC, HESTIA (the Herodotus Encoded Space-Text-Imaging Archive) aims to enrich contemporary discussions of space by developing an innovative methodology for the study of an ancient narrative, Herodotus’s Histories. Using the latest digital technology in combination with close textual study, we investigate the geographical concepts through which Herodotus describes the conflict between Greeks and Persians. Our findings nuance the customary topographical vision of an east versus west polarity by drawing attention to the topological network culture that criss-crosses the two, and develop the means of bringing that world to a mass audience via the internet. In this paper we discuss three main aspects to the project: the data capture of place-names in Herodotus; their visualization and dissemination using the web-mapping technologies of GIS, Google Earth and Timemap; and the interrogation of the relationships that Herodotus draws between different geographical concepts using the digital resources at our disposal. Our concern will be to set out in some detail the digital basis to our methodology and the technologies that we have been exploiting, as well as the problems that we have encountered, in the hope of contributing not only to a more complex picture of space in Herodotus but also to a basis for future digital projects across the Humanities that spatially visualize large text-based corpora. With this in mind we end with a brief discussion of some of the ways in which this study is being developed, with assistance from research grants from the Google Digital Humanities Awards Program and JISC.

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