Numerical Representation of Directed Acyclic Graphs for Efficient Dataflow Embedded Resource Allocation

International audienceStream processing applications running on Heterogeneous Multi-Processor Systems on Chips (HMPSoCs) require efficient resource allocation and management, both at compile-time and at runtime. To cope with modern adaptive applications whose behavior can not be exhaustively predicted at compile-time, runtime managers must be able to take resource allocation decisions on-the-fly, with a minimum overhead on application performance. Resource allocation algorithms often rely on an internal modeling of an application. Directed Acyclic Graph (DAGs) are the most commonly used models for capturing control and data dependencies between tasks. DAGs are notably often used as an intermediate representation for deploying applications modeled with a dataflow Model of Computation (MoC) on HMPSoCs. Building such intermediate representation at runtime for massively parallel applications is costly both in terms of computation and memory overhead. In this paper, an intermediate representation of DAGs for resource allocation is presented. This new representation shows improved performance for run-time analysis of dataflow graphs with less overhead in both computation time and memory footprint. The performances of the proposed representation are evaluated on a set of computer vision and machine learning applications

LOW POWER SOFTWARE HEVC DECODER DEMO FOR MOBILE DEVICES

Demo sessionInternational audienc

Power-Aware HEVC Decoding with Tunable Image Quality

International audienceA high pressure is put on mobile devices to support increasingly advanced applications requiring more processing capabilities. Among those, the emerging High Efficiency Video Coding (HEVC) provides a better video quality for the same bit rate than the previous H.264 standard. A limitation in the usability of a mobile video playing device is the lack of support for guaranteeing stand-by time and up time for battery driven devices. The Green Metadata initiative within the MPEG standard was launched to address the power saving issues of the decoder and defines the technology requirements. In this paper, we propose a HEVC decoder with tunable decoding quality levels for maximum power savings as suggested in the scope of the Green Metadata initiative. Our experiments reveal that the modified HEVC video decoder can save up to 28 % of power consumption in real-world platforms while keeping better quality than decoding with H.264

Acute idiopathic heart failure following laparoscopic myotomy for achalasia of the esophagus

Background: Stress-induced cardiomyopathy, also known as takotsubo cardiomyopathy, is not fully understood. It is thought to occur in patients who have signs and symptoms consistent with acute myocardial infarction but display no obstructive coronary lesions during heart catheterization. Characteristics include transient left ventricular dysfunction, wall motion abnormalities on echocardiogram, new electrocardiographic ST-segment changes, and the occurrence of a precipitating stressor. Case Report: We present a patient who underwent Heller myotomy and suffered acute heart failure in the immediate postoperative period. Left heart catheterization revealed clean coronary arteries, and the patient fully recovered days later. While difficult to fully exclude drug-related causes, we believe this case to be consistent with takotsubo cardiomyopathy. Conclusion: This unusual postoperative complication following uneventful laparoscopic surgery should be kept in mind when unsuspected cardiovascular compromise is seen in the early perioperative recovery period. In addition to the rare occurrence of acute coronary ischemia syndromes and possible perioperative pulmonary embolic events, cardiovascular decompensation related to acute stress syndromes or idiopathic pharmacologic responses must be considered. Even patients who seem most healthy can have complications that warrant immediate attention and treatment

Study of temperature, air dew point temperature and reactant flow effects on PEMFC performances using electrochemical spectroscopy and voltammetry techniques

A single PEMFC has been operated by varying the assembly temperature, the air dew point temperature and the anode/cathode stoichiometry rates with the aim to identify the parameters and combinations of factors affecting the cell performance. Some of the experiments were conducted with low humidified reactants (relative humidity of 12%). The FC characterizations tests have been conducted using in-situ electrochemical methods based on load current and cell voltage signal analysis, namely: polarization curves, EIS measurements, cyclic and linear sweep voltammetries (CV and LSV). The impacts of the parameters on the global FC performances were observed using the polarization curves whereas EIS, CV and LSV test results were used to discriminate the different voltage loss sources. The test results suggest that some parameter sets allow maximal output voltages but can also induce material degradation. For instance, higher FC temperature and air flow values can induce significant electrical efficiency benefits, notably by increasing the reversible potential and the reaction kinetics. However, raising the cell temperature can also gradually dry the FC and increase the risk of membrane failure. LSV has also shown that elevated FC temperature and relative humidity can also accelerate the electrolyte degradation (i.e. slightly higher fuel crossover rate) and reduce the lifetime consequently. PEMFC; Characterization; Electrochemical Impedance Spectroscopy; Cyclic Voltammetry; Linear Sweep Voltammetr

ECONOMIC IMPACTS RESULTING FROM CO-FIRING BIOMASS FEEDSTOCKS IN SOUTHEASTERN UNITED STATES COAL-FIRED PLANTS

Economic impacts of using biomass in Southeast United States coal-fired plants are estimated using a county-level biomass database; ORCED, a dynamic electricity distribution model that estimates feedstock value; ORIBAS, a GIS model that estimates feedstock transportation costs; and IMPLAN, an input-output model that determines the impacts of co-firing on economic activity.Resource /Energy Economics and Policy,

Machine Learning based Efficient QT-MTT Partitioning Scheme for VVC Intra Encoders

The next-generation Versatile Video Coding (VVC) standard introduces a new Multi-Type Tree (MTT) block partitioning structure that supports Binary-Tree (BT) and Ternary-Tree (TT) splits in both vertical and horizontal directions. This new approach leads to five possible splits at each block depth and thereby improves the coding efficiency of VVC over that of the preceding High Efficiency Video Coding (HEVC) standard, which only supports Quad-Tree (QT) partitioning with a single split per block depth. However, MTT also has brought a considerable impact on encoder computational complexity. In this paper, a two-stage learning-based technique is proposed to tackle the complexity overhead of MTT in VVC intra encoders. In our scheme, the input block is first processed by a Convolutional Neural Network (CNN) to predict its spatial features through a vector of probabilities describing the partition at each 4x4 edge. Subsequently, a Decision Tree (DT) model leverages this vector of spatial features to predict the most likely splits at each block. Finally, based on this prediction, only the N most likely splits are processed by the Rate-Distortion (RD) process of the encoder. In order to train our CNN and DT models on a wide range of image contents, we also propose a public VVC frame partitioning dataset based on existing image dataset encoded with the VVC reference software encoder. Our proposal relying on the top-3 configuration reaches 46.6% complexity reduction for a negligible bitrate increase of 0.86%. A top-2 configuration enables a higher complexity reduction of 69.8% for 2.57% bitrate loss. These results emphasis a better trade-off between VTM intra coding efficiency and complexity reduction compared to the state-of-the-art solutions