22,093 research outputs found
Impact of parameter variations on circuits and microarchitecture
Parameter variations, which are increasing along with advances in process technologies, affect both timing and power. Variability must be considered at both the circuit and microarchitectural design levels to keep pace with performance scaling and to keep power consumption within reasonable limits. This article presents an overview of the main sources of variability and surveys variation-tolerant circuit and microarchitectural approaches.Peer ReviewedPostprint (published version
Modeling the Temperature Bias of Power Consumption for Nanometer-Scale CPUs in Application Processors
We introduce and experimentally validate a new macro-level model of the CPU
temperature/power relationship within nanometer-scale application processors or
system-on-chips. By adopting a holistic view, this model is able to take into
account many of the physical effects that occur within such systems. Together
with two algorithms described in the paper, our results can be used, for
instance by engineers designing power or thermal management units, to cancel
the temperature-induced bias on power measurements. This will help them gather
temperature-neutral power data while running multiple instance of their
benchmarks. Also power requirements and system failure rates can be decreased
by controlling the CPU's thermal behavior.
Even though it is usually assumed that the temperature/power relationship is
exponentially related, there is however a lack of publicly available physical
temperature/power measurements to back up this assumption, something our paper
corrects. Via measurements on two pertinent platforms sporting nanometer-scale
application processors, we show that the power/temperature relationship is
indeed very likely exponential over a 20{\deg}C to 85{\deg}C temperature range.
Our data suggest that, for application processors operating between 20{\deg}C
and 50{\deg}C, a quadratic model is still accurate and a linear approximation
is acceptable.Comment: Submitted to SAMOS 2014; International Conference on Embedded
Computer Systems: Architectures, Modeling, and Simulation (SAMOS XIV
Wireless Communications in the Era of Big Data
The rapidly growing wave of wireless data service is pushing against the
boundary of our communication network's processing power. The pervasive and
exponentially increasing data traffic present imminent challenges to all the
aspects of the wireless system design, such as spectrum efficiency, computing
capabilities and fronthaul/backhaul link capacity. In this article, we discuss
the challenges and opportunities in the design of scalable wireless systems to
embrace such a "bigdata" era. On one hand, we review the state-of-the-art
networking architectures and signal processing techniques adaptable for
managing the bigdata traffic in wireless networks. On the other hand, instead
of viewing mobile bigdata as a unwanted burden, we introduce methods to
capitalize from the vast data traffic, for building a bigdata-aware wireless
network with better wireless service quality and new mobile applications. We
highlight several promising future research directions for wireless
communications in the mobile bigdata era.Comment: This article is accepted and to appear in IEEE Communications
Magazin
On Mitigation of Side-Channel Attacks in 3D ICs: Decorrelating Thermal Patterns from Power and Activity
Various side-channel attacks (SCAs) on ICs have been successfully
demonstrated and also mitigated to some degree. In the context of 3D ICs,
however, prior art has mainly focused on efficient implementations of classical
SCA countermeasures. That is, SCAs tailored for up-and-coming 3D ICs have been
overlooked so far. In this paper, we conduct such a novel study and focus on
one of the most accessible and critical side channels: thermal leakage of
activity and power patterns. We address the thermal leakage in 3D ICs early on
during floorplanning, along with tailored extensions for power and thermal
management. Our key idea is to carefully exploit the specifics of material and
structural properties in 3D ICs, thereby decorrelating the thermal behaviour
from underlying power and activity patterns. Most importantly, we discuss
powerful SCAs and demonstrate how our open-source tool helps to mitigate them.Comment: Published in Proc. Design Automation Conference, 201
SARAS: a precision system for measurement of the Cosmic Radio Background and signatures from the Epoch of Reionization
SARAS is a correlation spectrometer purpose designed for precision
measurements of the cosmic radio background and faint features in the sky
spectrum at long wavelengths that arise from redshifted 21-cm from gas in the
reionization epoch. SARAS operates in the octave band 87.5-175 MHz. We present
herein the system design arguing for a complex correlation spectrometer
concept. The SARAS design concept provides a differential measurement between
the antenna temperature and that of an internal reference termination, with
measurements in switched system states allowing for cancellation of additive
contaminants from a large part of the signal flow path including the digital
spectrometer. A switched noise injection scheme provides absolute spectral
calibration. Additionally, we argue for an electrically small
frequency-independent antenna over an absorber ground. Various critical design
features that aid in avoidance of systematics and in providing calibration
products for the parametrization of other unavoidable systematics are described
and the rationale discussed. The signal flow and processing is analyzed and the
response to noise temperatures of the antenna, reference termination and
amplifiers is computed. Multi-path propagation arising from internal
reflections are considered in the analysis, which includes a harmonic series of
internal reflections. We opine that the SARAS design concept is advantageous
for precision measurement of the absolute cosmic radio background spectrum;
therefore, the design features and analysis methods presented here are expected
to serve as a basis for implementations tailored to measurements of a
multiplicity of features in the background sky at long wavelengths, which may
arise from events in the dark ages and subsequent reionization era.Comment: 49 pages, 17 figure
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