36,402 research outputs found

    Modifications and Improvements to the Sea Beam System on Board R/V Thomas Washington

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    A number of modifications to the narrowbeam echo-sounder and echo processor of the Sea Beammultibeam bathymetric survey system have been implemented. These include the design and construction of a digital pitch compensator, the ability to use a variety of sensors for vertical reference, the design and construction of hardware test equipment, and an interface to the shipboard DEC VAX-11/730 computer for data logging, automation of start-up procedures, and performance monitorin

    Janus: An Uncertain Cache Architecture to Cope with Side Channel Attacks

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    Side channel attacks are a major class of attacks to crypto-systems. Attackers collect and analyze timing behavior, I/O data, or power consumption in these systems to undermine their effectiveness in protecting sensitive information. In this work, we propose a new cache architecture, called Janus, to enable crypto-systems to introduce randomization and uncertainty in their runtime timing behavior and power utilization profile. In the proposed cache architecture, each data block is equipped with an on-off flag to enable/disable the data block. The Janus architecture has two special instructions in its instruction set to support the on-off flag. Beside the analytical evaluation of the proposed cache architecture, we deploy it in an ARM-7 processor core to study its feasibility and practicality. Results show a significant variation in the timing behavior across all the benchmarks. The new secure processor architecture has minimal hardware overhead and significant improvement in protecting against power analysis and timing behavior attacks.Comment: 4 pages, 4 figure

    Microprocessor fault-tolerance via on-the-fly partial reconfiguration

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    This paper presents a novel approach to exploit FPGA dynamic partial reconfiguration to improve the fault tolerance of complex microprocessor-based systems, with no need to statically reserve area to host redundant components. The proposed method not only improves the survivability of the system by allowing the online replacement of defective key parts of the processor, but also provides performance graceful degradation by executing in software the tasks that were executed in hardware before a fault and the subsequent reconfiguration happened. The advantage of the proposed approach is that thanks to a hardware hypervisor, the CPU is totally unaware of the reconfiguration happening in real-time, and there's no dependency on the CPU to perform it. As proof of concept a design using this idea has been developed, using the LEON3 open-source processor, synthesized on a Virtex 4 FPG

    Synchronized computational architecture for generalized bilateral control of robot arms

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    A master six degree of freedom Force Reflecting Hand Controller (FRHC) is available at a master site where a received image displays, in essentially real time, a remote robotic manipulator which is being controlled in the corresponding six degree freedom by command signals which are transmitted to the remote site in accordance with the movement of the FRHC at the master site. Software is user-initiated at the master site in order to establish the basic system conditions, and then a physical movement of the FRHC in Cartesean space is reflected at the master site by six absolute numbers that are sensed, translated and computed as a difference signal relative to the earlier position. The change in position is then transmitted in that differential signal form over a high speed synchronized bilateral communication channel which simultaneously returns robot-sensed response information to the master site as forces applied to the FRHC so that the FRHC reflects the feel of what is taking place at the remote site. A system wide clock rate is selected at a sufficiently high rate that the operator at the master site experiences the Force Reflecting operation in real time

    An OpenSHMEM Implementation for the Adapteva Epiphany Coprocessor

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    This paper reports the implementation and performance evaluation of the OpenSHMEM 1.3 specification for the Adapteva Epiphany architecture within the Parallella single-board computer. The Epiphany architecture exhibits massive many-core scalability with a physically compact 2D array of RISC CPU cores and a fast network-on-chip (NoC). While fully capable of MPMD execution, the physical topology and memory-mapped capabilities of the core and network translate well to Partitioned Global Address Space (PGAS) programming models and SPMD execution with SHMEM.Comment: 14 pages, 9 figures, OpenSHMEM 2016: Third workshop on OpenSHMEM and Related Technologie
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