Power consumption can be significantly reduced in Systems-on-Chip (SoC) by scaling down the voltage levels of the Processing Elements (PEs). The power efficiency of this Voltage Islanding technique comes at the cost o...
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ISBN:
(纸本)9783981080162
Power consumption can be significantly reduced in Systems-on-Chip (SoC) by scaling down the voltage levels of the Processing Elements (PEs). The power efficiency of this Voltage Islanding technique comes at the cost of energy and area overhead due to the level shifters between voltage islands. Moreover, from the physical design perspective it is not desirable to have an excessive number of voltage islands on the chip. Considering voltage islanding at an early phase of design as during floorplanning of the PEs can address various of these issues. In this paper, we propose a new cost function for the floorplanning objective different from the traditional floorplanning objective. The new cost function not only includes the overall area requirement, but also incorporates the overall power consumption and the design constraint imposed on the maximum number of voltage islands. We propose a greedy heuristic based on the proposed cost function for the floorplanning of the PEs with several voltage islands. Experimental results using benchmark data study the effect of several parameters on the outcome of the heuristic. It is evident from the results that power consumption can be significantly reduced using our algorithm without significant area overhead. The area obtained from the heuristic is also compared with the optimal, and found to be within 4% of the optimal on average, when area minimization is given the priority.
Collaborating across disciplines can be a difficult task for a variety of reasons. One of which is the lack of common methodologies and tools for visualization and analysis. Tools developed in one group can rarely be ...
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ISBN:
(纸本)9780816910656
Collaborating across disciplines can be a difficult task for a variety of reasons. One of which is the lack of common methodologies and tools for visualization and analysis. Tools developed in one group can rarely be applied directly to data from another group, due to differences in data formats, analysis methodologies, and learning curves associated with the advanced visualization systems necessary for modern scientific data. Despite these difficulties, multi-physics collaboration is key to developing and understanding the next generation of computational models, which couple the dynamic processes and scales of multiple disciplines. As a step towards integrative models, we propose a visualization and analysis system to serve as a common interconnect between chemical and nuclear engineering. This choice allows multiple organizations to fruitfully exchange data and example visualizations in a reproducible manner, providing a foundation for productive discussion. In this work, we demonstrate the utility of a visualization system as it applies to bridging simulation domains and providing for multidisciplinary research in nuclear and chemical engineering.
Micro Aerial Vehicles (MAVs) and larger Unmanned Aerial Vehicles (UAVs) constitute a powerful tool for the modern warfighter and first responder. However, every developing technology must first be tested before being ...
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The transport of electrons in a semiconductor superlattice miniband under the influence of electrical and magnetic fields, which are applied in different directions on the superlattice, is investigated. The time serie...
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The authors have implemented a nonlinear constitutive modeling for ionomer membranes with application in polymer electrolyte membrane fuel cells. The constitutive model features multiplicative decomposition of visco-e...
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A correction to the article "Constraints on the Cosmic-Ray Density Gradient Beyond the Solar Circule From Fermi γ-Ray Observations of the Third Galactic Quadrant" that was published in the 2011 issue.
A correction to the article "Constraints on the Cosmic-Ray Density Gradient Beyond the Solar Circule From Fermi γ-Ray Observations of the Third Galactic Quadrant" that was published in the 2011 issue.
The generation of arbitrarily shaped nonspherical laser-induced cavitation bubbles is demonstrated with a optical technique. The nonspherical bubbles are formed using laser intensity patterns shaped by a spatial light...
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The generation of arbitrarily shaped nonspherical laser-induced cavitation bubbles is demonstrated with a optical technique. The nonspherical bubbles are formed using laser intensity patterns shaped by a spatial light modulator using linear absorption inside a liquid gap with a thickness of 40 μm. In particular we demonstrate the dynamics of elliptic, toroidal, square, and V-shaped bubbles. The bubble dynamics is recorded with a high-speed camera at framing rates of up to 300 000 frames per second. The observed bubble evolution is compared to predictions from an axisymmetric boundary element simulation which provides good qualitative agreement. Interesting dynamic features that are observed in both the experiment and simulation include the inversion of the major and minor axis for elliptical bubbles, the rotation of the shape for square bubbles, and the formation of a unidirectional jet for V-shaped bubbles. Further we demonstrate that specific bubble shapes can either be formed directly through the intensity distribution of a single laser focus, or indirectly using secondary bubbles that either confine the central bubble or coalesce with the main bubble. The former approach provides the ability to generate in principle any complex bubble geometry.
We employ a parallel, three-dimensional level-set code to simulate the dynamics of isolated dislocation lines and loops in an obstacle-rich environment. This system serves as a convenient prototype of those in which e...
We employ a parallel, three-dimensional level-set code to simulate the dynamics of isolated dislocation lines and loops in an obstacle-rich environment. This system serves as a convenient prototype of those in which extended, one-dimensional objects interact with obstacles and the out-of-plane motion of these objects is key to understanding their pinning-depinning behavior. In contrast to earlier models of dislocation motion, we incorporate long-ranged interactions among dislocation segments and obstacles to study the effect of climb on dislocation dynamics in the presence of misfitting penetrable obstacles/solutes, as embodied in an effective climb mobility. Our main observations are as follows. First, increasing climb mobility leads to more effective pinning by the obstacles, implying increased strengthening. Second, decreasing the range of interactions significantly reduces the effect of climb. The dependence of the critical stress on obstacle concentration and misfit strength is also explored and compared with existing models. In particular, our results are shown to be in reasonable agreement with the Friedel-Suzuki theory. Finally, the limitations inherent in the simplified model employed here, including the neglect of some lattice effects and the use of a coarse-grained climb mobility, are discussed.
Results are presented from empirical evaluation of a borescope simulator developed for non-destructive inspection training. Two experiments were conducted, manipulating camera rotation constraint and provision of hapt...
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ISBN:
(纸本)9781568814704
Results are presented from empirical evaluation of a borescope simulator developed for non-destructive inspection training. Two experiments were conducted, manipulating camera rotation constraint and provision of haptic feedback. Performance of experienced borescope inspectors is measured in terms of speed and accuracy, with accuracy clearly shown to improve by placing constraints on the simulator's camera tip rotation and by providing haptic response. This is important as damage avoidance of a real borescope is a critical criterion of borescope inspection training. These are likely to be the first such experiments to have been conducted with aircraft engine inspectors evaluating the potential of haptics in borescope simulation.
The last few years have seen considerable interest in the wireless networking research community in analyzing the connectivity of wireless ad-hoc networks formed by a set of nodes distributed in a two dimensional plan...
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ISBN:
(纸本)9781424458707
The last few years have seen considerable interest in the wireless networking research community in analyzing the connectivity of wireless ad-hoc networks formed by a set of nodes distributed in a two dimensional plane (deployment area) with a (i) uniform probability density function and (ii) uniform transmission range. Although several important and interesting results are known in this domain, most of the connectivity studies consider a fault-free scenario where all nodes are available for network formation and do not consider failures among nodes caused by one reason or another. In very few studies where faults are considered, they are usually considered to be random in nature, i.e., the probability of a node failing is independent of its location in the deployment area. However, such fault scenario is inadequate to capture many realistic situations where the faulty nodes are spatially correlated. This is particularly true in combat environment where an enemy bomb can destroy a subset of nodes confined to a region. In this paper we investigate the impact of region-based faults on the connectivity of wireless networks. Through analysis and simulation, we provide results relating the probability of a network being connected as transmission range and the size of fault-region are varied. If d min (G) denotes the minimum node degree of the network, we provide the analytical expression for P(d min (G) ¿ k), which represents the probability of the minimum node degree being at least k, for k = 1. Moreover, we compute P(¿(G) ¿ k), where ¿(G) represents the connectivity of the graph G formed by the distribution of nodes in the deployment area and examine the relationship between P(d min (G) ¿ k) and P(¿(G) ¿ k) when k = 1.
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