25,014 research outputs found

    Near-Memory Address Translation

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    Memory and logic integration on the same chip is becoming increasingly cost effective, creating the opportunity to offload data-intensive functionality to processing units placed inside memory chips. The introduction of memory-side processing units (MPUs) into conventional systems faces virtual memory as the first big showstopper: without efficient hardware support for address translation MPUs have highly limited applicability. Unfortunately, conventional translation mechanisms fall short of providing fast translations as contemporary memories exceed the reach of TLBs, making expensive page walks common. In this paper, we are the first to show that the historically important flexibility to map any virtual page to any page frame is unnecessary in today's servers. We find that while limiting the associativity of the virtual-to-physical mapping incurs no penalty, it can break the translate-then-fetch serialization if combined with careful data placement in the MPU's memory, allowing for translation and data fetch to proceed independently and in parallel. We propose the Distributed Inverted Page Table (DIPTA), a near-memory structure in which the smallest memory partition keeps the translation information for its data share, ensuring that the translation completes together with the data fetch. DIPTA completely eliminates the performance overhead of translation, achieving speedups of up to 3.81x and 2.13x over conventional translation using 4KB and 1GB pages respectively.Comment: 15 pages, 9 figure

    The Structure and Dynamics of the Upper Chromosphere and Lower Transition Region as Revealed by the Subarcsecond VAULT Observations

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    The Very high Angular resolution ULtraviolet Telescope (VAULT) is a sounding rocket payload built to study the crucial interface between the solar chromosphere and the corona by observing the strongest line in the solar spectrum, the Ly-a line at 1216 {\AA}. In two flights, VAULT succeeded in obtaining the first ever sub-arcsecond (0.5") images of this region with high sensitivity and cadence. Detailed analyses of those observations have contributed significantly to new ideas about the nature of the transition region. Here, we present a broad overview of the Ly-a atmosphere as revealed by the VAULT observations, and bring together past results and new analyses from the second VAULT flight to create a synthesis of our current knowledge of the high-resolution Ly-a Sun. We hope that this work will serve as a good reference for the design of upcoming Ly-a telescopes and observing plans.Comment: 28 pages, 11 figure

    Secure, performance-oriented data management for nanoCMOS electronics

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    The EPSRC pilot project Meeting the Design Challenges of nanoCMOS Electronics (nanoCMOS) is focused upon delivering a production level e-Infrastructure to meet the challenges facing the semiconductor industry in dealing with the next generation of ‘atomic-scale’ transistor devices. This scale means that previous assumptions on the uniformity of transistor devices in electronics circuit and systems design are no longer valid, and the industry as a whole must deal with variability throughout the design process. Infrastructures to tackle this problem must provide seamless access to very large HPC resources for computationally expensive simulation of statistic ensembles of microscopically varying physical devices, and manage the many hundreds of thousands of files and meta-data associated with these simulations. A key challenge in undertaking this is in protecting the intellectual property associated with the data, simulations and design process as a whole. In this paper we present the nanoCMOS infrastructure and outline an evaluation undertaken on the Storage Resource Broker (SRB) and the Andrew File System (AFS) considering in particular the extent that they meet the performance and security requirements of the nanoCMOS domain. We also describe how metadata management is supported and linked to simulations and results in a scalable and secure manner

    The Serums Tool-Chain:Ensuring Security and Privacy of Medical Data in Smart Patient-Centric Healthcare Systems

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    Digital technology is permeating all aspects of human society and life. This leads to humans becoming highly dependent on digital devices, including upon digital: assistance, intelligence, and decisions. A major concern of this digital dependence is the lack of human oversight or intervention in many of the ways humans use this technology. This dependence and reliance on digital technology raises concerns in how humans trust such systems, and how to ensure digital technology behaves appropriately. This works considers recent developments and projects that combine digital technology and artificial intelligence with human society. The focus is on critical scenarios where failure of digital technology can lead to significant harm or even death. We explore how to build trust for users of digital technology in such scenarios and considering many different challenges for digital technology. The approaches applied and proposed here address user trust along many dimensions and aim to build collaborative and empowering use of digital technologies in critical aspects of human society

    Challenges and perspectives for the protection of masonry structures in historic centers: the role of innovative materials and techniques

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    Lessons learned from natural events which caused severe damage to existing constructions have repeatedly shown the high vulnerability of historically important masonry, often worsened by inaccurate or dubious applications of modern or innovative interventions. Especially in the field of new technologies and materials applied to historical assets, experimental validation integrated at multi-disciplinary level is essential, to implement correct choices able to balance the respect of tradition and the requirements of innovation. The common objective is the transmission of educational values through the conservation of the historical identity of constructions which have survived over time and are still functional today. Planning agreements among academic and industrial research, management and governing bodies constitute preconditions for selecting consistent strategies for the protection of the built environment. However, the effects of technical advances and trends on historical assets should be carefully evaluated when influencing common practices, before recommendations, standards or execution protocols based on sufficiently long-lasting experience are available. This paper discusses a series of issues involved in the complex process of methodological and operative options currently feasible in the field of historical masonry structures. It also focuses on the progressive role of composite materials and the consequent implications on the implementation of preservation criteria

    Download Entire Issue: Gibbon Surgical Review, Volume 1, Issue 1, 2018

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    Table of Contents A First Year\u27s Perspective on JeffMD, Somnath Das, MS1 Spotlight on TJUH\u27s Quality and Safety Group, Samantha L. Savitch, MS1 Medical Student Involvement in Quality Improvement Research, Tyler M. Bauer, MS3 Global Surgery: A Shift in the Global Health Paradigm, Myles S. Dworkin, MS3 Thomas Jefferson University Design Vault, Victor B. Hsue, MS2 Physician Spotlight: Ernest (Gary) L. Rosato, MD, FACS, Carrie E. Andrews, MS3 The SCALPELS Program, Emily Papai, MS

    A Method to Evaluate the Stimulation of a Real World Field of View by Means of a Spectroradiometric Analysis

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    Stimulation elicited by a real world field of view is related to the color, the intensity and the direction of the information reaching the eye: different spectral power distributions of light trigger different responses. An evaluation of the stimulation provided by the field of view can be performed by measuring the spectral radiance with a spectroradiometer and weighting this data with an efficiency curve. Different weights (physical, physiological and psychological) can lead to different analyses and consequently to different results. The proposed method allows an overall and simplified evaluation of the field of view based on spectral and luminance measures and a script that processes the luminous information. The final aim of this approach is to provide further information about the light stimulation reaching the retina and to supply a qualitative evaluation of the field of view, allowing to know how much stimulation is coming from a certain area within the visual field depending on the type of surface, basing on spectral and directional information. This approach can have practical implications, allowing technicians and designers to take into consideration the possible visual fields, in order to properly shape the features of stimulation throughout the day, hence following a field of view-based dynamic design
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