345 research outputs found
On-Chip Transparent Wire Pipelining (invited paper)
No full textWire pipelining has been proposed as a viable mean to break the discrepancy between decreasing gate delays and increasing wire delays in deep-submicron technologies. Far from being a straightforwardly applicable technique, this methodology requires a number of design modifications in order to insert it seamlessly in the current design flow. In this paper we briefly survey the methods presented by other researchers in the field and then we thoroughly analyze the solutions we recently proposed, ranging from system-level wire pipelining to physical design aspects
Engineering a Bandwidth-Scalable Optical Layer for a 3D Multi-core Processor with Awareness of Layout Constraints
No full textThe performance of future chip multi-processors will only scale with the number of integrated cores if there is a corresponding increase in memory access efficiency. The focus of this paper on a 3D-stacked wavelength-routed optical layer for high bandwidth and low latency processor-memory communication goes in this direction and complements ongoing efforts on photonically integrated bandwidth-rich DRAM devices. This target environment dictates layout constraints that make the difference in discriminating between alternative design choices of the optical layer. This paper assesses network partitioning options and bandwidth scalability techniques with deep technology and layout awareness, the main contribution lying in the characterization and precise quantification of such interaction effects between the technology platform, the layout constraints and the network-level quality metrics of a passive optical NoC
Renormalizability of the Dirac equation in torsion gravity with nonminimal coupling
No full textWe will consider the torsional completion of gravity for a background filled with Dirac matter fields,
studying what happens when fermionic nonminimal coupling is taken into account: we will show that,
although nonminimal couplings are usually disregarded because of their ill-defined behavior in ultraviolet
regimes, this is due to the fact that torsion is commonly neglected, whereas when torsion is not left aside,
even nonminimal couplings behave properly. In detail, we will see that nonminimal coupling allows one to
renormalize the Dirac equation even when torsion is taken into consideration and that in some type of
nonminimally coupled models parity oddness might be present even in the gravitational sector. In addition,
we will show that in the presence of the considered nonminimal coupling, torsion is able to evade
cosmological singularities as it can happen in the minimal coupling case and in some other nonminimally
coupled theory. In the course of the paper, we shall consider a specific interaction as prototype to study this
fermionic nonminimal coupling, but we will try to present results that do not depend on the actual structure
of the nonminimal couplings by investigating alternative types of interaction
Torsion gravity with nonminimally coupled fermionic field: Some cosmological models
No full textWe investigate some cosmological models arising from a nonminimal coupling of a fermionic field to
gravity in the geometrical setting of Einstein-Cartan-Sciama-Kibble gravity. In the presence of torsion,
we discuss the role played by the nonminimal coupling together with fermionic self-interaction potentials
in facing problems such as cosmological singularity, inflation, and dark energy
The dynamics of Bianchi I universes in cosmologies with torsion
No full textWe analyze the phase space of Bianchi I cosmologies filled by a spin fluid in the framework of -gravity with torsion using a combination of the dynamical systems approach and the 1+3 covariant formalism. In the simple case of our results allow a quantification of the role of torsion and the spin of the cosmic fluid in the evolution of the cosmology. While torsion is able to modify the cosmological dynamics with respect to the purely metric case, the spin has little influence on the cosmology. We argue that this is due to the different symmetries of the tensor characterizing the anisotropies and the spin tensor. The cosmological model we analyzed presents isotropization for a wide set of initial conditions and values of the parameters and allows for two types of exotic bounce solutions
A design methodology for compositional high-level synthesis of communication-centric SoCs
No full textSystems-on-chip are increasingly designed at the system level by combining synthesizable IP components that operate concurrently while interacting through communication channels. CAD-tool vendors support this System-Level Design approach with high-level synthesis tools and libraries of interface primitives implementing the communication protocols. These interfaces absorb timing differences in the hardware-component implementations, thus enabling compositional design. However, they introduce also new challenges in terms of functional correctness and performance optimization. We propose a methodology that combines performance analysis and optimization algorithms to automatically address the issues that SoC designers may accidentally introduce when assembling components that are specified at the system level. Copyright 2014 ACM
Experimental analysis of fiber reinforced cementitious matrix (FRCM) confined masonry columns
No full textThe increasing use of Fiber Reinforced methods for strengthening existing brick masonry walls and columns, especially for the rehabilitation of historical buildings, has generated considerable research interest in understanding the failure mechanism in such systems.
This dissertation is aimed to provide a basic understanding of the behavior of solid brick masonry walls unwrapped and wrapped with Fiber Reinforced Cementitious Matrix Composites. This is a new type of composite material, commonly known as FRCM, featuring a cementitious inorganic matrix (binder) instead of the more common epoxy one.
The influence of the FRCM-reinforcement on the load-carrying capacity and strain distribution during compression test will be investigated using a full-field optical technique known as Digital Image Correlation.
Compression test were carried on 6 clay bricks columns and on 7 clay brick walls in three different configuration, casted using bricks scaled respect the first one with a ratio 1:2, in order to determinate the effects of FRCM reinforcement.
The goal of the experimental program is to understand how the behavior of brick masonry will be improved by the FRCM-wrapping.
The results indicate that there is an arching action zone represented in the form of a parabola with a varying shape according to the used configuration. The area under the parabolas is considered as ineffectively confined.
The effectively confined area is assumed to occur within the region where the arching action had been fully developed
Accelerators for Breast Cancer Detection
No full textAlgorithms used in microwave imaging for breast cancer detection require hardware acceleration to speedup execution time and reduce power consumption. In this paper we present the hardware implementation of two accelerators for two alternative imaging algorithms that we obtain entirely from SystemC specifications via high-level synthesis. The two algorithms present opposite characteristics that stress the design process and the capabilities of commercial HLS tools in different ways: the first is communication-bound and requires overlapping and pipelining of communication and computation in order to maximize the application throughput; the second is computation-bound and uses complex mathematical functions that HLS tools do not directly support. Despite these difficulties, thanks to HLS in the span of four months only we were able to explore a large design space and derive about one hundred implementations with different cost-performance profiles, targeting both an FPGA platform and a 32-nm standard-cell ASIC library. In addition, we could obtain results that outperform a previous RTL implementation, which confirms the remarkable progress of HLS tools
System-level memory optimization for high-level synthesis of component-based SoCs
No full textThe design of specialized accelerators is essential to the success of many modern Systems-on-Chip. Electronic system-level design methodologies and high-level synthesis tools are critical for the efficient design and optimization of an accelerator. Still, these methodologies and tools offer only limited support for the optimization of the memory structures, which are often responsible for most of the area occupied by an accelerator. To address these limitations, we present a novel methodology to automatically derive the memory subsystems of SoC accelerators. Our approach enables compositional design-space exploration and promotes design reuse of the accelerator specifications. We illustrate its effective-ness by presenting experimental results on the design of two accelerators for a high-performance embedded application. Copyright 2014 ACM
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