1,216 research outputs found

    gMark: Schema-Driven Generation of Graphs and Queries

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    Massive graph data sets are pervasive in contemporary application domains. Hence, graph database systems are becoming increasingly important. In the experimental study of these systems, it is vital that the research community has shared solutions for the generation of database instances and query workloads having predictable and controllable properties. In this paper, we present the design and engineering principles of gMark, a domain- and query language-independent graph instance and query workload generator. A core contribution of gMark is its ability to target and control the diversity of properties of both the generated instances and the generated workloads coupled to these instances. Further novelties include support for regular path queries, a fundamental graph query paradigm, and schema-driven selectivity estimation of queries, a key feature in controlling workload chokepoints. We illustrate the flexibility and practical usability of gMark by showcasing the framework's capabilities in generating high quality graphs and workloads, and its ability to encode user-defined schemas across a variety of application domains.Comment: Accepted in November 2016. URL: http://ieeexplore.ieee.org/document/7762945/. in IEEE Transactions on Knowledge and Data Engineering 201

    Impact of a Yoga and Meditation Intervention on Students\u27 Stress and Anxiety Levels

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    Objective: To evaluate the impact of a 6-week yoga and meditation intervention on college students’ stress perception, anxiety levels and mindfulness skills. Methods. College students participated in a 6-week pilot program consisting of a 60-minute vinyasa yoga class followed by guided meditation once weekly, delivered by trained faculty at the University of Rhode Island College of Pharmacy. Students completed pre- and post-questionnaires to evaluate changes in the following outcomes: stress levels, anxiety levels, and mindfulness skills. The questionnaire was comprised of three self reporting tools: Beck Anxiety Inventory (BAI), Perceived Stress Scale (PSS), and Five Facet Mindfulness Questionnaire (FFMQ). Changes from baseline were assessed using numerical and categorical scales (low, medium, and high). Results. Seventeen participants (ages 19-23) completed the study. Thirteen participants were female, and four were male. Nine of the students were enrolled in the PharmD program and eight from other majors. Anxiety and stress scores decreased while total mindfulness increased, with all changes statistically significant. Categorical pre-post data from BAI and PSS were statistically significant with no students reported being in the “high” category of both stress and anxiety post intervention. Conclusion. Students demonstrated a reduction in stress and anxiety levels after completing a 6-week yoga and meditation program preceding final exams. Results suggest adopting a mindfulness practice for as little as once per week may reduce stress and anxiety in college students. Higher education may consider the inclusion of nonpharmacologic methods, such as yoga and meditation, to support student self-care

    Frequency Domain Simulations of Charge-Density-Wave Strains: Comparison with Electro-Optic Measurements

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    We have studied changes in charge-density-wave strain under application of square-wave currents of variable amplitude and frequency by numerically solving the phase-slip augmented diffusion model introduced by Adelman et al (Phys. Rev. B 53, 1833 (1996)). The frequency dependence of the strain, at each position and amplitude, was fit to a modified harmonic oscillator expression, and the position and current dependence of the fitting parameters determined. In particular, the delay time (1/resonant frequency) vanishes adjacent to the contact and grows with distance from the contact, and both the delay time and relaxation time decrease rapidly with increasing current (and phase-slip rate), as experimentally observed in the electro-optic response of blue bronze. We have also found that pinning the phase at the contacts causes more rapid changes in strain between the contacts than allowing the phase to flow outside the contacts.Comment: 12 pages, 4 figures, submitted to Phys. Rev.

    Tracking advanced persistent threats in critical infrastructures through opinion dynamics

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    Advanced persistent threats pose a serious issue for modern industrial environments, due to their targeted and complex attack vectors that are difficult to detect. This is especially severe in critical infrastructures that are accelerating the integration of IT technologies. It is then essential to further develop effective monitoring and response systems that ensure the continuity of business to face the arising set of cyber-security threats. In this paper, we study the practical applicability of a novel technique based on opinion dynamics, that permits to trace the attack throughout all its stages along the network by correlating different anomalies measured over time, thereby taking the persistence of threats and the criticality of resources into consideration. The resulting information is of essential importance to monitor the overall health of the control system and cor- respondingly deploy accurate response procedures. Advanced Persistent Threat Detection Traceability Opinion Dynamics.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Modeless Pointing with Low-Precision Wrist Movements

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    Part 1: Long and Short Papers (Continued)International audienceWrist movements are physically constrained and take place within a small range around the hand's rest position. We explore pointing techniques that deal with the physical constraints of the wrist and extend the range of its input without making use of explicit mode-switching mechanisms. Taking into account elastic properties of the human joints, we investigate designs based on rate control. In addition to pure rate control, we examine a hybrid technique that combines position and rate-control and a technique that applies non-uniform position-control mappings. Our experimental results suggest that rate control is particularly effective under low-precision input and long target distances. Hybrid and non-uniform position-control mappings, on the other hand, result in higher precision and become more effective as input precision increases
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