1,051 research outputs found

    Timed Analysis of Security Protocols

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    We propose a method for engineering security protocols that are aware of timing aspects. We study a simplified version of the well-known Needham Schroeder protocol and the complete Yahalom protocol, where timing information allows the study of different attack scenarios. We model check the protocols using UPPAAL. Further, a taxonomy is obtained by studying and categorising protocols from the well known Clark Jacob library and the Security Protocol Open Repository (SPORE) library. Finally, we present some new challenges and threats that arise when considering time in the analysis, by providing a novel protocol that uses time challenges and exposing a timing attack over an implementation of an existing security protocol

    Information activity in serious leisure

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    Background. In the past decade, scholars of information science have started to conduct research on information behaviour in serious leisure. Presently, these studies lack common concepts and terms and empirical discoveries are not easy to assemble into theory. Aim. This conceptual and methodological paper surveys the aforementioned research area and introduces Anders Hektor’s model of information behaviour in conjunction with the serious leisure perspective as a means to systematically study information behaviour in serious leisure. Method. Three methods are employed. The first is a selective literature review and intellectual history of research into information behaviour in serious leisure. The second is a conceptual analysis of Hektor’s model that relates its key features to the serious leisure perspective. The third consists of a deductive audit of three forms of serious leisure (the liberal arts hobby, amateur musicianship, and the hobby of running), utilizing the frameworks, concepts, and terms outlined in the paper. Results. Studies of information behaviour in serious leisure have increased and deepened in the past decade, largely through ideographic case studies. Hektor’s model of information behaviour, with its locus in everyday life and precise delineation of eight information activities, can complement such research designs. A deductive audit guided by Hektor’s model illuminated information activities within the three forms of serious leisure and enabled comparative observations. Conclusions. When combined with the serious leisure perspective, Hektor’s model enables research that is comparative and more precise. However, the extent to which this model captures physical or embodied information should be further examined

    Two methodologies for physical penetration testing using social engineering

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    Penetration tests on IT systems are sometimes coupled with physical penetration tests and social engineering. In physical penetration tests where social engineering is allowed, the penetration tester directly interacts with the employees. These interactions are usually based on deception and if not done properly can upset the employees, violate their privacy or damage their trust toward the organization and might lead to law suits and loss of productivity. We propose two methodologies for performing a physical penetration test where the goal is to gain an asset using social engineering. These methodologies aim to reduce the impact of the penetration test on the employees. The methodologies have been validated by a set of penetration tests performed over a period of two year

    The treatment of primary tumors of the femur with chemotherapy (if indicated), resection and reconstruction with an endoprosthesis

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    The treatment protocol of 15 patients with a primary tumor of the femur, including osteosarcoma, malignant fibrous histiocytoma and chondrosar-coma is presented. All patients had been selected for resection and reconstruction with an endoprosthesis. An endoprothesis was implanted in 12 patients. \ud The results of this type of treatment appear to be satisfactory. In eight osteosarcoma cases resection and reconstruction with an endoprosthesis combined with preoperative and postoperative chemotherapy, according to Rosen, were performed. Follow-up in all 15 patients, varying from 1.4 to 6.0 years, showed no evidence of disease in 12 patients. Three patients had died. Function of the involved leg was satisfactory in most cases. \ud The advantage and disadvantages of the use of an endoprosthesis are discussed as well as complications in this series of patients

    First irradiation results using the neurosphere formation assay

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    Proton radiography of cells administered with gold Nanoparticles

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    Demonstrating Advantages of Neuromorphic Computation: A Pilot Study

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    Neuromorphic devices represent an attempt to mimic aspects of the brain's architecture and dynamics with the aim of replicating its hallmark functional capabilities in terms of computational power, robust learning and energy efficiency. We employ a single-chip prototype of the BrainScaleS 2 neuromorphic system to implement a proof-of-concept demonstration of reward-modulated spike-timing-dependent plasticity in a spiking network that learns to play the Pong video game by smooth pursuit. This system combines an electronic mixed-signal substrate for emulating neuron and synapse dynamics with an embedded digital processor for on-chip learning, which in this work also serves to simulate the virtual environment and learning agent. The analog emulation of neuronal membrane dynamics enables a 1000-fold acceleration with respect to biological real-time, with the entire chip operating on a power budget of 57mW. Compared to an equivalent simulation using state-of-the-art software, the on-chip emulation is at least one order of magnitude faster and three orders of magnitude more energy-efficient. We demonstrate how on-chip learning can mitigate the effects of fixed-pattern noise, which is unavoidable in analog substrates, while making use of temporal variability for action exploration. Learning compensates imperfections of the physical substrate, as manifested in neuronal parameter variability, by adapting synaptic weights to match respective excitability of individual neurons.Comment: Added measurements with noise in NEST simulation, add notice about journal publication. Frontiers in Neuromorphic Engineering (2019

    Radioresistant subpopulation in a culture of glioma-initiating cells

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