scholarly journals An Integrated Hardware Array for Very High Speed Logic Simulation

VLSI Design ◽  
1996 ◽  
Vol 4 (2) ◽  
pp. 107-118
Author(s):  
E. Scott Fehr ◽  
Stephen A. Szygenda ◽  
Granville E. Ott
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Functional Verification ◽  
Logic Simulation ◽  
Switching Circuits ◽  
Direct Model ◽  
Architectural Innovation ◽  
Order Of Magnitude ◽  
Architectural Principles ◽  
Ordered Design

A hardware architecture is proposed which allows direct mapping of design simulation topology onto an acceleration platform. In order to clarify architectural principles, the simulation is confined to functional verification of unit delay, binary valued gate level logic designs. Under this approach, a rank ordered design description is executed on a massively parallel processor grid which implements an efficient and direct model of the design, similar to prototyping. Architectural innovation reduces logic complexity and execution time of boolean evaluation and fanout switching circuits, while large scale parallelism is integrated at die level to reduce cost and communication delays. The results of this research form the basis for a multiple order of magnitude improvement in reported state-of-the-art cost-performance merit for hardware gate level simulation accelerators.

Scaling Laws for Ultra-Short Hydrostatic Gas Journal Bearings

2003 ◽  
Author(s):  
Z. S. Spakovszky ◽  
L. X. Liu
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Scaling Laws ◽  
Damping Ratio ◽  
Journal Bearings ◽  
Gas Bearings ◽  
Outer Periphery ◽  
Order Of Magnitude ◽  
Design Speed ◽  
Annular Seals

The journal bearings of the MIT micro-devices are located at the outer periphery of the rotor and are designed to operate at rotational speeds of order 2 million rpm in order to enable high-power densities with turbomachinery tip speeds near 500 m/s. These journal bearings are very short compared to their relatively large bearing diameters such that the bearing L/D is typically less than 0.1, that is at least one order of magnitude smaller than in conventional gas bearings. Thus, the ultra-short micro gas journal bearings essentially act as short annular seals and operate at Reynolds numbers of order 300, two orders of magnitude lower than conventional annular seals. The concepts that hold for turbulent flow, large scale annular seals do not apply to micro bearings and the laminar flow regime sets new challenges in the design, implementation and operation of ultra-short, high-speed gas bearings. In order to reach the goal of operating the MIT micro devices at full design speed, the micro-bearing design must be improved and engineering solutions need to be found to overcome the challenges of high-speed bearing operation. This paper is the first to derive the scaling laws for the dynamics of ultrashort hydrostatic gas journal bearings. The theory is established from first principles and enables a physics based characterization of the dynamic behavior of ultra-short hydrostatic gas bearings. The derived scaling laws for natural frequency and damping ratio show good agreement with experimental data. A simple criterion for whirl instability is found that only depends on bearing geometry. The scaling laws together with this criterion are used to delineate engineering solutions critical for stable high-speed bearing operation. Design charts are developed which provide the link between fabrication tolerances, bearing performance, and the tolerable level of rotor unbalance for a minimum required whirl ratio.

Scaling Laws for Ultra-Short Hydrostatic Gas Journal Bearings

2005 ◽  
Vol 127 (3) ◽  
pp. 254-261 ◽  
Author(s):  
Z. S. Spakovszky ◽  
L. X. Liu
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Scaling Laws ◽  
Damping Ratio ◽  
Journal Bearings ◽  
Gas Bearings ◽  
Outer Periphery ◽  
Order Of Magnitude ◽  
Design Speed ◽  
Annular Seals

The journal bearings of the MIT micro-devices are located at the outer periphery of the rotor and are designed to operate at rotational speeds of order two million rpm in order to enable high-power densities with turbomachinery tip speeds near 500m/s. These journal bearings are very short compared to their relatively large bearing diameters such that the bearing L/D is typically less than 0.1, that is at least one order of magnitude smaller than in conventional gas bearings. Thus, the ultra-short micro gas journal bearings essentially act as short annular seals and operate at Reynolds numbers of order 300, two orders of magnitude lower than conventional annular seals. The concepts that hold for turbulent flow, large scale annular seals do not apply to micro bearings and the laminar flow regime sets new challenges in the design, implementation and operation of ultra-short, high-speed gas bearings. In order to reach the goal of operating the MIT micro devices at full design speed, the micro-bearing design must be improved and engineering solutions need to be found to overcome the challenges of high-speed bearing operation. This paper is the first to derive the scaling laws for the dynamics of ultra-short hydrostatic gas journal bearings. The theory is established from first principles and enables a physics based characterization of the dynamic behavior of ultra-short hydrostatic gas bearings. The derived scaling laws for natural frequency and damping ratio show good agreement with experimental data. A simple criterion for whirl instability is found that only depends on bearing geometry. The scaling laws together with this criterion are used to delineate engineering solutions critical for stable high-speed bearing operation. Design charts are developed which provide the link between fabrication tolerances, bearing performance, and the tolerable level of rotor unbalance for a minimum required whirl ratio.

Do elite soccer players cover longer distance when losing? Differences between attackers and defenders

2020 ◽  
pp. 174795412098227
Author(s):  
Carlos Lago-Peñas ◽  
Anton Kalén ◽  
Miguel Lorenzo-Martinez ◽  
Roberto López-Del Campo ◽  
Ricardo Resta ◽  
...  
Keyword(s):  
New York ◽  
High Speed ◽  
Large Scale ◽  
Tracking System ◽  
Soccer Players ◽  
Running Performance ◽  
Situational Variables ◽  
Total Distance ◽  
Professional Soccer ◽  
Score Line

This study aimed to evaluate the effects playing position, match location (home or away), quality of opposition (strong or weak), effective playing time (total time minus stoppages), and score-line on physical match performance in professional soccer players using a large-scale analysis. A total of 10,739 individual match observations of outfield players competing in the Spanish La Liga during the 2018–2019 season were recorded using a computerized tracking system (TRACAB, Chyronhego, New York, USA). The players were classified into five positions (central defenders, players = 94; external defenders, players = 82; central midfielders, players = 101; external midfielders, players = 72; and forwards, players = 67) and the following match running performance categories were considered: total distance covered, low-speed running (LSR) distance (0–14 km · h−1), medium-speed running (MSR) distance (14–21 km · h−1), high-speed running (HSR) distance (>21 km · h−1), very HSR (VHSR) distance (21–24 km · h−1), sprint distance (>24 km · h−1) Overall, match running performance was highly dependent on situational variables, especially the score-line condition (winning, drawing, losing). Moreover, the score-line affected players running performance differently depending on their playing position. Losing status increased the total distance and the distance covered at MSR, HSR, VHSR and Sprint by defenders, while attacking players showed the opposite trend. These findings may help coaches and managers to better understand the effects of situational variables on physical performance in La Liga and could be used to develop a model for predicting the physical activity profile in competition.

scholarly journals 1.5 °C degrowth scenarios suggest the need for new mitigation pathways

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lorenz T. Keyßer ◽  
Manfred Lenzen
Keyword(s):  
Technological Change ◽  
High Speed ◽  
Large Scale ◽  
High Energy ◽  
Climate Mitigation ◽  
Intergovernmental Panel ◽  
Economic Output ◽  
Integrated Assessment Modelling ◽  
Negative Emissions ◽  
Energy Emissions

Abstract1.5  °C scenarios reported by the Intergovernmental Panel on Climate Change (IPCC) rely on combinations of controversial negative emissions and unprecedented technological change, while assuming continued growth in gross domestic product (GDP). Thus far, the integrated assessment modelling community and the IPCC have neglected to consider degrowth scenarios, where economic output declines due to stringent climate mitigation. Hence, their potential to avoid reliance on negative emissions and speculative rates of technological change remains unexplored. As a first step to address this gap, this paper compares 1.5  °C degrowth scenarios with IPCC archetype scenarios, using a simplified quantitative representation of the fuel-energy-emissions nexus. Here we find that the degrowth scenarios minimize many key risks for feasibility and sustainability compared to technology-driven pathways, such as the reliance on high energy-GDP decoupling, large-scale carbon dioxide removal and large-scale and high-speed renewable energy transformation. However, substantial challenges remain regarding political feasibility. Nevertheless, degrowth pathways should be thoroughly considered.

scholarly journals Nebula: ultra-efficient mapping-free structural variant genotyper

2021 ◽  
Author(s):  
Parsoa Khorsand ◽  
Fereydoun Hormozdiari
Keyword(s):  
Large Scale ◽  
Structural Variants ◽  
Sequencing Technologies ◽  
Generic Framework ◽  
Common Genetic Variants ◽  
Order Of Magnitude ◽  
Complex Events ◽  
Comparable Accuracy ◽  
Using Data ◽  
Computational Resources

Abstract Large scale catalogs of common genetic variants (including indels and structural variants) are being created using data from second and third generation whole-genome sequencing technologies. However, the genotyping of these variants in newly sequenced samples is a nontrivial task that requires extensive computational resources. Furthermore, current approaches are mostly limited to only specific types of variants and are generally prone to various errors and ambiguities when genotyping complex events. We are proposing an ultra-efficient approach for genotyping any type of structural variation that is not limited by the shortcomings and complexities of current mapping-based approaches. Our method Nebula utilizes the changes in the count of k-mers to predict the genotype of structural variants. We have shown that not only Nebula is an order of magnitude faster than mapping based approaches for genotyping structural variants, but also has comparable accuracy to state-of-the-art approaches. Furthermore, Nebula is a generic framework not limited to any specific type of event. Nebula is publicly available at https://github.com/Parsoa/Nebula.

scholarly journals Large-Scale Object Monitoring in Internet-of-Things: Energy-Efficient Perspectives

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 461
Author(s):  
Yongbin Yim ◽  
Euisin Lee ◽  
Seungmin Oh
Keyword(s):  
Energy Efficient ◽  
Large Scale ◽  
Future Research ◽  
Technological Evolution ◽  
Node Density ◽  
Mobile Objects ◽  
Research Challenges ◽  
Energy Efficient Communication ◽  
Efficient Communication ◽  
Architectural Principles

Recently, the demand for monitoring a certain object covering large and dynamic scopes such as wildfires, glaciers, and radioactive contaminations, called large-scale fluid objects (LFOs), is coming to the fore due to disasters and catastrophes that lately happened. This article provides an analytic comparison of such LFOs and typical individual mobile objects (IMOs), namely animals, humans, vehicles, etc., to figure out inherent characteristics of LFOs. Since energy-efficient monitoring of IMOs has been intensively researched so far, but such inherent properties of LFOs hinder the direct adaptation of legacy technologies for IMOs, this article surveys technological evolution and advances of LFOs along with ones of IMOs. Based on the communication cost perspective correlated to energy efficiency, three technological phases, namely concentration, integration, and abbreviation, are defined in this article. By reviewing various methods and strategies employed by existing works with the three phases, this article concludes that LFO monitoring should achieve not only decoupling from node density and network structure but also trading off quantitative reduction against qualitative loss as architectural principles of energy-efficient communication to break through inherent properties of LFOs. Future research challenges related to this topic are also discussed.

scholarly journals Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
High Speed ◽  
Large Scale ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Sampled Data ◽  
Residential Areas ◽  
Terrain Rendering ◽  
Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

scholarly journals Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4143
Author(s):  
Youzheng Cui ◽  
Shenrou Gao ◽  
Fengjuan Wang ◽  
Qingming Hu ◽  
Cheng Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Volume Fraction ◽  
Simulation Analysis ◽  
Cutting Temperature ◽  
High Volume ◽  
Cutting Parameters ◽  
High Volume Fraction ◽  
High Wear Resistance ◽  
Element Analysis

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc= 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

scholarly journals LiDAR Point Cloud Recognition and Visualization with Deep Learning for Overhead Contact Inspection

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6387 ◽  
Author(s):  
Xiaohan Tu ◽  
Cheng Xu ◽  
Siping Liu ◽  
Shuai Lin ◽  
Lipei Chen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Computational Complexity ◽  
Point Cloud ◽  
High Speed ◽  
Point Cloud Data ◽  
Embedded Devices ◽  
Cloud Data ◽  
Manual Inspection ◽  
Order Of Magnitude ◽  
Supply Systems

As overhead contact (OC) is an essential part of power supply systems in high-speed railways, it is necessary to regularly inspect and repair abnormal OC components. Relative to manual inspection, applying LiDAR (light detection and ranging) to OC inspection can improve efficiency, accuracy, and safety, but it faces challenges to efficiently and effectively segment LiDAR point cloud data and identify catenary components. Recent deep learning-based recognition methods are rarely employed to recognize OC components, because they have high computational complexity, while their accuracy needs to be improved. To track these problems, we first propose a lightweight model, RobotNet, with depthwise and pointwise convolutions and an attention module to recognize the point cloud. Second, we optimize RobotNet to accelerate its recognition speed on embedded devices using an existing compilation tool. Third, we design software to facilitate the visualization of point cloud data. Our software can not only display a large amount of point cloud data, but also visualize the details of OC components. Extensive experiments demonstrate that RobotNet recognizes OC components more accurately and efficiently than others. The inference speed of the optimized RobotNet increases by an order of magnitude. RobotNet has lower computational complexity than other studies. The visualization results also show that our recognition method is effective.

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