48 research outputs found

    A proof-of-proximity framework for device pairing in ubiquitous computing environments

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    Ad hoc interactions between devices over wireless networks in ubiquitous computing environments present a security problem: the generation of shared secrets to initialize secure communication over a medium that is inherently vulnerable to various attacks. However, these ad hoc scenarios also offer the potential for physical security of spaces and the use of protocols in which users must visibly demonstrate their presence and/or involvement to generate an association. As a consequence, recently secure device pairing has had significant attention from a wide community of academic as well as industrial researchers and a plethora of schemes and protocols have been proposed, which use various forms of out-of-band exchange to form an association between two unassociated devices. These protocols and schemes have different strengths and weaknesses – often in hardware requirements, strength against various attacks or usability in particular scenarios. From ordinary user‟s point of view, the problem then becomes which to choose or which is the best possible scheme in a particular scenario. We advocate that in a world of modern heterogeneous devices and requirements, there is a need for mechanisms that allow automated selection of the best protocols without requiring the user to have an in-depth knowledge of the minutiae of the underlying technologies. Towards this, the main argument forming the basis of this dissertation is that the integration of a discovery mechanism and several pairing schemes into a single system is more efficient from a usability point of view as well as security point of view in terms of dynamic choice of pairing schemes. In pursuit of this, we have proposed a generic system for secure device pairing by demonstration of physical proximity. Our main contribution is the design and prototype implementation of Proof-of-Proximity framework along with a novel Co- Location protocol. Other contributions include a detailed analysis of existing device pairing schemes, a simple device discovery mechanism, a protocol selection mechanism that is used to find out the best possible scheme to demonstrate the physical proximity of the devices according to the scenario, and a usability study of eight pairing schemes and the proposed system

    System Support for Managing Invalid Bindings

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    Context-aware adaptation is a central aspect of pervasive computing applications, enabling them to adapt and perform tasks based on contextual information. One of the aspects of context-aware adaptation is reconfiguration in which bindings are created between application component and remote services in order to realize new behaviour in response to contextual information. Various research efforts provide reconfiguration support and allow the development of adaptive context-aware applications from high-level specifications, but don't consider failure conditions that might arise during execution of such applications, making bindings between application and remote services invalid. To this end, we propose and implement our design approach to reconfiguration to manage invalid bindings. The development and modification of adaptive context-aware applications is a complex task, and an issue of an invalidity of bindings further complicates development efforts. To reduce the development efforts, our approach provides an application-transparent solution where the issue of the invalidity of bindings is handled by our system, Policy-Based Contextual Reconfiguration and Adaptation (PCRA), not by an application developer. In this paper, we present and describe our approach to managing invalid bindings and compare it with other approaches to this problem. We also provide performance evaluation of our approach

    Some variant of Tseng splitting method with accelerated Visco-Cesaro means for monotone inclusion problems

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    In this paper, we examine the convergence analysis of a variant of Tseng's splitting method for monotone inclusion problem and fixed point problem associated with an infinite family of η \eta -demimetric mappings in Hilbert spaces. The qualitative results of the proposed variant shows strong convergence characteristics under a suitable set of control conditions. We also provide a numerical example to demonstrate the applicability of the variant with some applications

    Network Analysis of co-authorship system of University of Sindh authors on Science Direct

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    Many complex systems have been modelled and analyzed as complex networks. These systems are huge and complex in terms of number of interconnecting components. In this research, we have analyzed the co-authorship network of Sindh university authors on science direct to understand the connectivity pattern of authors who published their articles over time. This research has found that the connectivity pattern of the authors is highly heterogonous due to the emergence of hubs in this system. Further, this network has shown highly clustered behavior with small world effect. These findings based on network analysis suggests that the co-authorship system is depending on few authors frequently publishing multiple papers in this network

    Enzymatically assisted extraction of antioxidant and anti-mutagenic compounds from radish (Raphanus sativus)

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    In addition to being sources of carbohydrates, protein, and fiber, vegetables, and fruits also represent important sources of micro-nutrients, including antioxidants, and anti-mutagens in the form of carotenoids, and polyphenols, such as flavonoids. We describe the enhanced extraction of these bioactive compounds from radish (Raphanus sativus L.) by use of an enzymic pre-treatment to break up starch, and the complex mix of polysaccharides, cellulose, hemicellulose, and pectin, which constitute the plant cell wall. The enzymic cocktail included cellulases, pectinases, amylases, glucanases, and hemicellulases. Response surface methodology (RSM) was utilized to maximally explore the yield by estimating extraction conditions, enzyme concentration, incubation time, temperature, pH, and extraction solvents. Extracted antioxidant activity was assayed in terms of total phenolics content (TPC), free radical scavenging (DPPH and ABTS tests), inhibition of linolic peroxidation assay, Reducing potential, and Trolox equivalent antioxidant capacity (TEAC). Two different bacterial mutant strains (TA-98, TA-100, S. typhimurium) were used by applying Ames bacterial test. It was concluded that highest desirability was achieved at 3.53% (w/w) of enzyme formulation, at pH of 6.1, incubation time 66.08 min and 46.08 °C temperature produced 19.2 g/100 g FW of crude extract which contains 45.9 mg GAE/g FW total phenolics contents, 0.480 mg/mL Reducing Power, 85.9% LA inhibition and 271.7 mmole/g FW of TEAC in fresh radish root. We found that radish extract was an excellent source of antioxidants that might be further investigated for commercial exploitation

    TEXTAROSSA: Towards EXtreme scale Technologies and Accelerators for euROhpc hw/Sw Supercomputing Applications for exascale

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    International audienceTo achieve high performance and high energy efficiency on near-future exascale computing systems, three key technology gaps needs to be bridged. These gaps include: energy efficiency and thermal control; extreme computation efficiency via HW acceleration and new arithmetics; methods andtools for seamless integration of reconfigurable accelerators in heterogeneous HPC multi-node platforms. TEXTAROSSA aims at tackling this gap through a co-design approach to heterogeneous HPC solutions, supported by the integration and extension of HW and SW IPs, programming models and tools derived from European research
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