960 research outputs found
Microlensing towards M31 with MDM data
We report the final analysis of a search for microlensing events in the
direction of the Andromeda galaxy, which aimed to probe the MACHO composition
of the M31 halo using data collected during the 1998-99 observational campaign
at the MDM observatory. In a previous paper, we discussed the results from a
first set of observations. Here, we deal with the complete data set, and we
take advantage of some INT observations in the 1999-2000 seasons. This merging
of data sets taken by different instruments turns out to be very useful, the
study of the longer baseline available allowing us to test the uniqueness
characteristic of microlensing events. As a result, all the candidate
microlensing events previously reported turn out to be variable stars. We
further discuss a selection based on different criteria, aimed at the detection
of short--duration events. We find three candidates whose positions are
consistent with self--lensing events, although the available data do not allow
us to conclude unambiguously that they are due to microlensing.Comment: Accepted for publication in Astronomy and Astrophysic
Force-directed scheduling in automatic data path synthesis
The HAL system performs data path synthesis using a new scheduling algorithm that 1s part Of an interdependent scheduling and allocation scheme. This scheme uses an BStl-mate of the hardware allocation to guide and optimiza the scheduling subtask. The allocation information includes the number. type. speed and cost of hardware modules as well as the associated multiplexer and interconnect costs. The iterative force-directed scheduling algorithm attempts to balance the distribution of operations that make use Of the same hardware resources:. Every feasible control step assignment is evaluated at each iteration, for a11 operations.. The associated side-effects on all the predecessor and successor operations are taken Into account.. All the decisions are global.. The algorithm has O(n*) complexity. We review and compare existing scheduling techniques. Mod-erate and difficult examples are used to illustrate the ef-fectiveness of the approach. 1
RNN-Based Radio Resource Management on Multicore RISC-V Accelerator Architectures
Radio resource management (RRM) is critical in 5G mobile communications due to its ubiquity on every radio device and its low latency constraints. The rapidly evolving RRM algorithms with low latency requirements combined with the dense and massive 5G base station deployment ask for an on-the-edge RRM acceleration system with a tradeoff between flexibility, efficiency, and cost-making application-specific instruction-set processors (ASIPs) an optimal choice. In this work, we start from a baseline, simple RISC-V core and introduce instruction extensions coupled with software optimizations for maximizing the throughput of a selected set of recently proposed RRM algorithms based on models using multilayer perceptrons (MLPs) and recurrent neural networks (RNNs). Furthermore, we scale from a single-ASIP to a multi-ASIP acceleration system to further improve RRM throughput. For the single-ASIP system, we demonstrate an energy efficiency of 218 GMAC/s/W and a throughput of 566 MMAC/s corresponding to an improvement of 10x and 10.6x, respectively, over the single-core system with a baseline RV32IMC core. For the multi-ASIP system, we analyze the parallel speedup dependency on the input and output feature map (FM) size for fully connected and LSTM layers, achieving up to 10.2x speedup with 16 cores over a single extended RI5CY core for single LSTM layers and a speedup of 13.8x for a single fully connected layer. On the full RRM benchmark suite, we achieve an average overall speedup of 16.4x, 25.2x, 31.9x, and 38.8x on two, four, eight, and 16 cores, respectively, compared to our single-core RV32IMC baseline implementation
Translations of Steinhausen's Publications Provide Insight Into Their Contributions to Peripheral Vestibular Neuroscience
The quantitative relationship between angular head movement and semicircular canal function is most often referenced to the well-known torsion-pendulum model that predicts cupular displacement from input head acceleration. The foundation of this model can be traced back to Steinhausen's series of papers between 1927 and 1933 whereby he endeavored to document observations of cupular displacements that would directly infer movement of the endolymph resulting from angular rotation. He also was the first to establish the direct relationship between cupular displacement and compensatory eye movements. While the chronology of these findings, with their successes and pitfalls, are documented in Steinhausen's work, it reflects a fascinating journey that has been inaccessible to the non-German speaking community. Therefore, the present compilation of translations, with accompanying introduction and discussion, was undertaken to allow a larger component of the vestibular scientific community to gain insight into peripheral labyrinthine mechanics provided by this historical account
Innovative small capacity gas driven ammonia-water absorption heat pump prototype for space heating and domestic hot water production
Fluid-fluid phase separation in a soft porous medium
Various biological and chemical processes lead to the nucleation and growth
of non-wetting fluid bubbles within the pore space of a granular medium, such
as the formation of gas bubbles in liquid-saturated lake-bed sediments. In
sufficiently soft porous materials, the non-wetting nature of these bubbles can
result in the formation of open cavities within the granular solid skeleton.
Here, we consider this process through the lens of phase separation, where
thermomechanics govern the separation of the non-wetting phase from a
fluid-fluid-solid mixture. We construct a phase-field model informed by
large-deformation poromechanics, in which two immiscible fluids interact with a
poroelastic solid skeleton. Our model captures the competing effects of
elasticity and fluid-fluid-solid interactions. We use a phase-field damage
model to capture the mechanics of the granular solid. As a model problem, we
consider an initial distribution of non-wetting fluid in the pore space that
separates into multiple cavities. We use simulations and linear-stability
analysis to identify the key parameters that control phase separation, the
conditions that favour the formation of cavities, and the characteristic size
of the resulting cavities
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