505 research outputs found

    Personalized content retrieval in context using ontological knowledge

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    Personalized content retrieval aims at improving the retrieval process by taking into account the particular interests of individual users. However, not all user preferences are relevant in all situations. It is well known that human preferences are complex, multiple, heterogeneous, changing, even contradictory, and should be understood in context with the user goals and tasks at hand. In this paper, we propose a method to build a dynamic representation of the semantic context of ongoing retrieval tasks, which is used to activate different subsets of user interests at runtime, in a way that out-of-context preferences are discarded. Our approach is based on an ontology-driven representation of the domain of discourse, providing enriched descriptions of the semantics involved in retrieval actions and preferences, and enabling the definition of effective means to relate preferences and context

    Personalized information retrieval based on context and ontological knowledge

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    The article has been accepted for publication and appeared in a revised form, subsequent to peer review and/or editorial input by Cambridge University PressExtended papers from C&O-2006, the second International Workshop on Contexts and Ontologies, Theory, Practice and Applications1 collocated with the seventeenth European Conference on Artificial Intelligence (ECAI)Context modeling has been long acknowledged as a key aspect in a wide variety of problem domains. In this paper we focus on the combination of contextualization and personalization methods to improve the performance of personalized information retrieval. The key aspects in our proposed approach are a) the explicit distinction between historic user context and live user context, b) the use of ontology-driven representations of the domain of discourse, as a common, enriched representational ground for content meaning, user interests, and contextual conditions, enabling the definition of effective means to relate the three of them, and c) the introduction of fuzzy representations as an instrument to properly handle the uncertainty and imprecision involved in the automatic interpretation of meanings, user attention, and user wishes. Based on a formal grounding at the representational level, we propose methods for the automatic extraction of persistent semantic user preferences, and live, ad-hoc user interests, which are combined in order to improve the accuracy and reliability of personalization for retrieval.This research was partially supported by the European Commission under contracts FP6-001765 aceMedia and FP6-027685 MESH. The expressed content is the view of the authors but not necessarily the view of the aceMedia or MESH projects as a whole

    Exploring the adoption of physical security controls in smartphones

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    The proliferation of smartphones has changed our life due to the enhanced connectivity, increased storage capacity and innovative functionality they offer. Their increased popularity has drawn the attention of attackers, thus, nowadays their users are exposed to many security and privacy threats. The fact that smartphones store significant data (e.g. personal, business, government, etc.) in combination with their mobility, increase the impact of unauthorized physical access to smartphones. However, past research has revealed that this is not clearly understood by smartphone users, as they disregard the available security controls. In this context, this paper explores the attitudes and perceptions towards security controls that protect smartphone user’s data from unauthorized physical access. We conducted a survey to measure their adoption and the rea-sons behind users’ selections. Our results, suggest that nowadays users are more concerned about their physical security, but still reveal that a considerable portion of our sample is prone to unauthorized physical access

    Induction of ovulation and spawning in the Mediterranean red porgy, Pagrus pagrus, by controlled delivery and acute injection of GnRHa

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    Gonadotropin-releasing hormone analogue (GnRHa) in the form of saline injections or sustained-release microspheres was used to induce oocyte maturation, ovulation, and spawning in captive red porgy (Pagrus pagrus). Individually tagged vitellogenic females (n = 9 or 10) were treated at the beginning of the spawning season (March) with 20 μg/kg body weight (bw) GnRHa-loaded microspheres, a single injection of 20 μg/kg bw dissolved in saline, or physiological saline (control). Females were placed in tanks (one tank per treatment) connected to overflow egg collectors and monitored for 11 days. In addition to the eggs collected from the tank overflow, eggs were stripped from the fish on a daily basis. Only one spawn was obtained from the control fish, probably from a single female, given the small relative fecundity (700 eggs/kg bw). On the contrary, treatment with a GnRHa injection produced two spawns (9 and 11 days after treatment) and 50% of the fish ovulated. Treatment with GnRHa microspheres induced seven spawns (3 and 6-11 days after treatment) and 100% of the females ovulated. Females did not spawn all the eggs ovulated on a particular day, evident from the significant number of eggs obtained by manual stripping. Egg quality did not significantly differ among treatments, whereas number of spawned eggs and total relative fecundity were significantly higher in fish treated with GnRHa microspheres (ANOVA, p<0.05). The results demonstrate the potential of GnRHaloaded microspheres to induce spawning in red porgy, as a method of overcoming spawning failures in commercial hatcheries

    Groupoids, Loop Spaces and Quantization of 2-Plectic Manifolds

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    We describe the quantization of 2-plectic manifolds as they arise in the context of the quantum geometry of M-branes and non-geometric flux compactifications of closed string theory. We review the groupoid approach to quantizing Poisson manifolds in detail, and then extend it to the loop spaces of 2-plectic manifolds, which are naturally symplectic manifolds. In particular, we discuss the groupoid quantization of the loop spaces of R^3, T^3 and S^3, and derive some interesting implications which match physical expectations from string theory and M-theory.Comment: 71 pages, v2: references adde

    Membrane Sigma-Models and Quantization of Non-Geometric Flux Backgrounds

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    We develop quantization techniques for describing the nonassociative geometry probed by closed strings in flat non-geometric R-flux backgrounds M. Starting from a suitable Courant sigma-model on an open membrane with target space M, regarded as a topological sector of closed string dynamics in R-space, we derive a twisted Poisson sigma-model on the boundary of the membrane whose target space is the cotangent bundle T^*M and whose quasi-Poisson structure coincides with those previously proposed. We argue that from the membrane perspective the path integral over multivalued closed string fields in Q-space is equivalent to integrating over open strings in R-space. The corresponding boundary correlation functions reproduce Kontsevich's deformation quantization formula for the twisted Poisson manifolds. For constant R-flux, we derive closed formulas for the corresponding nonassociative star product and its associator, and compare them with previous proposals for a 3-product of fields on R-space. We develop various versions of the Seiberg-Witten map which relate our nonassociative star products to associative ones and add fluctuations to the R-flux background. We show that the Kontsevich formula coincides with the star product obtained by quantizing the dual of a Lie 2-algebra via convolution in an integrating Lie 2-group associated to the T-dual doubled geometry, and hence clarify the relation to the twisted convolution products for topological nonassociative torus bundles. We further demonstrate how our approach leads to a consistent quantization of Nambu-Poisson 3-brackets.Comment: 52 pages; v2: references adde

    The international face of Thessaloniki: the “Greek crisis,” the entrepreneurial mayor, and mainstream media discourses

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    Thessaloniki and its mayor have been portrayed quite favourably in international mainstream media compared to the Greek state after the 2008 economic crisis. The dominant (media) discourses on Greece interpret the crisis as the result of the failure of the Greek state to reform due to the prevalence of a traditional political culture over a modern one and the moral failures of the population. In the international media representations of Thessaloniki, the local government has been described as “exceptional” in its crisis management compared to the state and other local governments, and the city's mayor, Yiannis Boutaris, has been portrayed as a reform hero, due to the implemented entrepreneurial development strategy and the revamp of the city's image through place branding. Analysing the key role of international media in the production and reproduction of a place-branding campaign of Thessaloniki in international media by employing critical discourse analysis, the paper questions the favourable representations of the city compared to the Greek state during the same period. I argue that the serial repetition of positive images contributed to Thessaloniki being perceived as an example to be followed by other Greek local governments and the central state, acting as a best practice example for transformations envisioned on wider scales. The paper contributes to place-branding debates by illustrating the important role of international media in the dissemination of place brands, and by analysing how media representations of place may serve the legitimation of processes of neoliberalisation on scales wider than the concrete urban setting where they occur

    The EAES intellectual property awareness survey

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    Introduction: The protection of intellectual property (IP) is one of the fundamental elements in the process of medical device development. The significance of IP, however, is not well understood among clinicians and researchers. The purpose of this study was to evaluate the current status of IP awareness and IP-related behaviors among EAES members. / Methods: A web-based survey was conducted via questionnaires sent to EAES members. Data collected included participant demographics, level of understanding the need, new ideas and solutions, basic IP knowledge, e.g., employees' inventions and public disclosure, behaviors before and after idea disclosures. / Results: One hundred and seventy-nine completed forms were obtained through an email campaign conducted twice in 2019 (response rate = 4.8%). There was a dominancy in male, formally-trained gastrointestinal surgeons, working at teaching hospitals in European countries. Of the respondents, 71% demonstrated a high level of understanding the needs (frustration with current medical devices), with 66% developing specific solutions by themselves. Active discussion with others was done by 53%. Twenty-one percent of respondents presented their ideas at medical congresses, and 12% published in scientific journals. Only 20% took specific precautions or appropriate actions to protect their IPs before these disclosures. / Conclusions: The current level of awareness of IP and IP-related issues is relatively low among EAES members. A structured IP training program to gain basic IP knowledge and skill should be considered a necessity for clinicians. These skills would serve to prevent the loss of legitimate IP rights and avoid failure in the clinical implementation of innovative devices for the benefit of patients
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