14 research outputs found
Dynamic Power Management for Neuromorphic Many-Core Systems
This work presents a dynamic power management architecture for neuromorphic
many core systems such as SpiNNaker. A fast dynamic voltage and frequency
scaling (DVFS) technique is presented which allows the processing elements (PE)
to change their supply voltage and clock frequency individually and
autonomously within less than 100 ns. This is employed by the neuromorphic
simulation software flow, which defines the performance level (PL) of the PE
based on the actual workload within each simulation cycle. A test chip in 28 nm
SLP CMOS technology has been implemented. It includes 4 PEs which can be scaled
from 0.7 V to 1.0 V with frequencies from 125 MHz to 500 MHz at three distinct
PLs. By measurement of three neuromorphic benchmarks it is shown that the total
PE power consumption can be reduced by 75%, with 80% baseline power reduction
and a 50% reduction of energy per neuron and synapse computation, all while
maintaining temporary peak system performance to achieve biological real-time
operation of the system. A numerical model of this power management model is
derived which allows DVFS architecture exploration for neuromorphics. The
proposed technique is to be used for the second generation SpiNNaker
neuromorphic many core system
Development of a GEM-TPC prototype
The use of GEM foils for the amplification stage of a TPC instead of a con-
ventional MWPC allows one to bypass the necessity of gating, as the backdrift
is suppressed thanks to the asymmetric field configuration. This way, a novel
continuously running TPC, which represents one option for the PANDA central
tracker, can be realized. A medium sized prototype with a diameter of 300 mm
and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using
a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector
test under realistic experimental conditions should allow us to verify the
spatial resolution for single tracks and the reconstruction capability for
displaced vertexes. A series of physics measurement implying pion beams is
scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como
(italy
Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study
Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality
Mass spectrometric studies on the in vivo metabolism and excretion of SIRT1 activating drugs in rat urine, dried blood spots, and plasma samples for doping control purposes
The NAD depending enzyme SIRT1 regulates the mitochondrial biogenesis, fat and glucose metabolism through catalyzing the deacetylation of several metabolism-related protein-substrates. Recently, synthetic activators of SIRT1 referred to as STACs (Sirtuin activating compounds, e.g. SRT2104) were identified and tested in clinical studies for the treatment of aging-related diseases such as type 2 diabetes, Alzheimer's and obesity. Although the mechanism of SIRT1 activation by small molecules has caused considerable controversy, STACs demonstrated a significant performance enhancement in mice experiments including an improvement of endurance, muscle strength, and locomotor behavior. Due to their potential to increase exercise tolerance in healthy individuals, SIRT1 activators are currently being monitored by anti-doping authorities. In the present study, the in vivo metabolic clearance of three SIRT1 activators was investigated in rats by the collection of urine, DBS (dried blood spots) and plasma samples following a single oral administration. The resulting metabolic products were studied by positive electrosp ray ionization - (tandem) mass spectrometry and confirmed by the comparison with in vitro generated metabolites using human and rat liver microsomal preparations. Subsequently, a screening procedure for five SIRT1 activators and the metabolite M1-SRT1720 in DBS specimens was developed. Liquid-liquid-extraction and liquid chromatography/tandem mass spectrometry was employed based on diagnostic ion transitions recorded in multiple reaction monitoring mode and two deuterated internal standards namely d(8)-SRT1720 and d(8)-M1-SRT1720 were utilized. The doping control assay was characterized with regard to specificity, limit of detection (10-50 ng/ml), recovery (65-83%) and imprecision (7-20%) and ion suppression/enhancement effects (<10%), demonstrating its fitness-for-purpose for sports drug testing applications. (C) 2013 Elsevier B.V. All rights reserved
Efficient Reward-Based Structural Plasticity on a SpiNNaker 2 Prototype
Advances in neuroscience uncover the mechanisms employed by the brain to
efficiently solve complex learning tasks with very limited resources. However,
the efficiency is often lost when one tries to port these findings to a silicon
substrate, since brain-inspired algorithms often make extensive use of complex
functions such as random number generators, that are expensive to compute on
standard general purpose hardware. The prototype chip of the 2nd generation
SpiNNaker system is designed to overcome this problem. Low-power ARM processors
equipped with a random number generator and an exponential function accelerator
enable the efficient execution of brain-inspired algorithms. We implement the
recently introduced reward-based synaptic sampling model that employs
structural plasticity to learn a function or task. The numerical simulation of
the model requires to update the synapse variables in each time step including
an explorative random term. To the best of our knowledge, this is the most
complex synapse model implemented so far on the SpiNNaker system. By making
efficient use of the hardware accelerators and numerical optimizations the
computation time of one plasticity update is reduced by a factor of 2. This,
combined with fitting the model into to the local SRAM, leads to 62% energy
reduction compared to the case without accelerators and the use of external
DRAM. The model implementation is integrated into the SpiNNaker software
framework allowing for scalability onto larger systems. The hardware-software
system presented in this work paves the way for power-efficient mobile and
biomedical applications with biologically plausible brain-inspired algorithms.Comment: accepted by IEEE TBioCA
Comparing Loihi with a SpiNNaker 2 prototype on low-latency keyword spotting and adaptive robotic control
We implemented two neural network based benchmark tasks on a prototype chip
of the second-generation SpiNNaker (SpiNNaker 2) neuromorphic system: keyword
spotting and adaptive robotic control. Keyword spotting is commonly used in
smart speakers to listen for wake words, and adaptive control is used in
robotic applications to adapt to unknown dynamics in an online fashion. We
highlight the benefit of a multiply accumulate (MAC) array in the SpiNNaker 2
prototype which is ordinarily used in rate-based machine learning networks when
employed in a neuromorphic, spiking context. In addition, the same benchmark
tasks have been implemented on the Loihi neuromorphic chip, giving a
side-by-side comparison regarding power consumption and computation time. While
Loihi shows better efficiency when less complicated vector-matrix
multiplication is involved, with the MAC array, the SpiNNaker 2 prototype shows
better efficiency when high dimensional vector-matrix multiplication is
involved
Hardware Acceleration of EEG-based Emotion Classification Systems: A Comprehensive Survey
10.1109/tbcas.2021.3089132IEEE Transactions on Biomedical Circuits and Systems1-
An Evaluation of Function of Multicopy Noncoding RNAs in Mammals Using ENCODE/FANTOM Data and Comparative Genomics
Structure and TBP binding of the Mediator head subcomplex Med8–Med18–Med20
The Mediator head module stimulates basal RNA polymerase II (Pol II) transcription and enables transcriptional regulation. Here we show that the head subunits Med8, Med18 and Med20 form a subcomplex (Med8/18/20) with two submodules. The highly conserved N-terminal domain of Med8 forms one submodule that binds the TATA box–binding protein (TBP) in vitro and is essential in vivo. The second submodule consists of the C-terminal region of Med8 (Med8C), Med18 and Med20. X-ray analysis of this submodule reveals that Med18 and Med20 form related beta-barrel folds. A conserved putative protein-interaction face on the Med8C/18/20 submodule includes sites altered by srb mutations, which counteract defects resulting from Pol II truncation. Our results and published data support a positive role of the Med8/18/20 subcomplex in initiation-complex formation and suggest that the Mediator head contains a multipartite TBP-binding site that can be modulated by transcriptional activators