22 research outputs found

    OR Residual Connection Achieving Comparable Accuracy to ADD Residual Connection in Deep Residual Spiking Neural Networks

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    Spiking Neural Networks (SNNs) have garnered substantial attention in brain-like computing for their biological fidelity and the capacity to execute energy-efficient spike-driven operations. As the demand for heightened performance in SNNs surges, the trend towards training deeper networks becomes imperative, while residual learning stands as a pivotal method for training deep neural networks. In our investigation, we identified that the SEW-ResNet, a prominent representative of deep residual spiking neural networks, incorporates non-event-driven operations. To rectify this, we introduce the OR Residual connection (ORRC) to the architecture. Additionally, we propose the Synergistic Attention (SynA) module, an amalgamation of the Inhibitory Attention (IA) module and the Multi-dimensional Attention (MA) module, to offset energy loss stemming from high quantization. When integrating SynA into the network, we observed the phenomenon of "natural pruning", where after training, some or all of the shortcuts in the network naturally drop out without affecting the model's classification accuracy. This significantly reduces computational overhead and makes it more suitable for deployment on edge devices. Experimental results on various public datasets confirmed that the SynA enhanced OR-Spiking ResNet achieved single-sample classification with as little as 0.8 spikes per neuron. Moreover, when compared to other spike residual models, it exhibited higher accuracy and lower power consumption. Codes are available at https://github.com/Ym-Shan/ORRC-SynA-natural-pruning.Comment: 16 pages, 8 figures and 11table

    The temporal trend of disease burden attributable to metabolic risk factors in China, 1990–2019 : An analysis of the Global Burden of Disease study

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    Background and aims: The disease burden attributable to metabolic risk factors is rapidly increasing in China, especially in older people. The objective of this study was to (i) estimate the pattern and trend of six metabolic risk factors and attributable causes in China from 1990 to 2019, (ii) ascertain its association with societal development, and (iii) compare the disease burden among the Group of 20 (G20) countries. Methods: The main outcome measures were disability-adjusted life-years (DALYs) and mortality (deaths) attributable to high fasting plasma glucose (HFPG), high systolic blood pressure (HSBP), high low-density lipoprotein (HLDL) cholesterol, high body-mass index (HBMI), kidney dysfunction (KDF), and low bone mineral density (LBMD). The average annual percent change (AAPC) between 1990 and 2019 was analyzed using Joinpoint regression. Results: For all six metabolic risk factors, the rate of DALYs and death increased with age, accelerating for individuals older than 60 and 70 for DALYs and death, respectively. The AAPC value in rate of DALYs and death were higher in male patients than in female patients across 20 age groups. A double-peak pattern was observed for AAPC in the rate of DALYs and death, peaking at age 20–49 and at age 70–95 plus. The age-standardized rate of DALYs increased for HBMI and LBMD, decreased for HFPG, HSBP, KDF, and remained stable for HLDL from 1990 to 2019. In terms of age-standardized rate of DALYs, there was an increasing trend of neoplasms and neurological disorders attributable to HFPG; diabetes and kidney diseases, neurological disorders, sense organ diseases, musculoskeletal disorders, neoplasms, cardiovascular diseases, digestive diseases to HBMI; unintentional injuries to LBMD; and musculoskeletal disorders to KDF. Among 19 countries of Group 20, in 2019, the age-standardized rate of DALYs and death were ranked fourth to sixth for HFPG, HSBP, and HLDL, but ranked 10th to 15th for LBMD, KDF, and HBMI, despite the number of DALYs and death ranked first to second for six metabolic risk factors. Conclusions: Population aging continuously accelerates the metabolic risk factor driven disease burden in China. Comprehensive and tight control of metabolic risk factors before 20 and 70 may help to mitigate the increasing disease burden and achieve healthy aging, respectively

    Study on the Influence of Delamination Damage on the Processing Quality of Composite Laminates

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    Internal delamination damage in composite connection structures can occur in the process of the overloading of a high-speed bearing, with alternating force loads, high or low temperatures, and the humid or hot environment loads. Mechanical drilling and riveting are usually used at the delamination position and outside its envelope, to inhibit delamination expansion. However, delamination damage can change the structural stress state of the original structure. It is difficult to achieve a better inhibition effect using conventional drilling mechanisms and process methods with intact composite panels, and new damage forms can even be introduced into the drilling process due to unreasonable parameter settings. Therefore, this paper combined finite element simulation technology and experimental processing technology, to analyze the influence of different delamination dimensions and positions on processing quality. The results showed that the feed speed and rotating speed had significant effects on the axial force of composite laminates. In particular, in the case of a low speed and high feed, the axial force will increase significantly

    HIV-1 Envelope Glycoprotein at the Interface of Host Restriction and Virus Evasion

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    Without viral envelope proteins, viruses cannot enter cells to start infection. As the major viral proteins present on the surface of virions, viral envelope proteins are a prominent target of the host immune system in preventing and ultimately eliminating viral infection. In addition to the well-appreciated adaptive immunity that produces envelope protein-specific antibodies and T cell responses, recent studies have begun to unveil a rich layer of host innate immune mechanisms restricting viral entry. This review focuses on the exciting progress that has been made in this new direction of research, by discussing various known examples of host restriction of viral entry, and diverse viral countering strategies, in particular, the emerging role of viral envelope proteins in evading host innate immune suppression. We will also highlight the effective cooperation between innate and adaptive immunity to achieve the synergistic control of viral infection by targeting viral envelope protein and checking viral escape. Given that many of the related findings were made with HIV-1, we will use HIV-1 as the model virus to illustrate the basic principles and molecular mechanisms on host restriction targeting HIV-1 envelope protein

    Spatial match analysis of multiple factors in the geopolitical environment of the Arctic Passage.

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    This study seeks to provide a basic approach to fulfill the spatial visualization of geopolitical environmental factors required for the navigation of vessels in the Arctic. Multi-dimensional geopolitical environmental factors of the Arctic Passage are analyzed and classified into geopolitics, geoeconomics, geo-military, geoculture, and laws and regulations related to geography. Their characteristics are extracted to form an attribute information table matching spatial layers. Based on the information category and basic characteristics, the spatial match method is applied and connected with the spatial layers to examine the spatial point, polyline, and polygon. According to the qualitative description, the study extracted the quantitative indicators for the following spatial-temporal pattern analysis. The standard deviational ellipse is used to analyze the spatial-temporal patterns and trends of the geopolitical environmental indicators of the Arctic Passage in the Arctic and Northeast Asia. The expansion and contraction of geoinformation coexist in the countries surrounding the Arctic Passage. The spatial-temporal changes indicate that the Arctic channel has a great economic impact on the Nordic countries and Northeast Asia, especially the coastal areas of China and Japan. The characteristic extraction and spatial match of the geopolitical environment provide integrated Arctic geoinformation inquiry and services for the diplomatic, administrative, and legal preparations required for Arctic navigation. Therefore, the geospatial analysis conducted provides scientific support and a basis for the geographical distribution and developing trends of visualization and spatial-temporal pattern in Arctic navigation. The results of this research will help decision-makers to make a comprehensive judgment on governance related to the sustainable development of the Arctic Passage

    Numerical Study on Thermal Hydraulic Performance of Supercritical LNG in Zigzag-Type Channel PCHEs

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    In this paper, we study a promising plate-type heat exchanger, the printed circuit heat exchanger (PCHE), which has high compactness and is suitable for high-pressure conditions as a vaporizer during vaporization. The thermal hydraulic performance of supercritical produce liquefied natural gas (LNG) in the zigzag channel of PCHE is numerically investigated using the SST κ-ω turbulence model. The thermo-physical properties of supercritical LNG from 6.5 MPa to 10MPa were calculated using piecewise-polynomial approximations of the temperature. The effect of the channel bend angle, mass flux and inlet pressure on local convection heat transfer coefficient, and pressure drop are discussed. The heat transfer and pressure loss performance are evaluated using the Nusselt and Euler numbers. Nu/Eu is proposed to evaluate the comprehensive heat transfer performance of PCHE by considering the heat transfer and pressure drop characteristics to find better bend angle and operating conditions. The supercritical LNG has a better heat transfer performance when bend angle is less than 15° with the mass flux ranging from 207.2 kg/(m2·s) to 621.6 kg/(m2·s), which improves at bend angle of 10° and lower compared to 15° at mass flux above 414.4 kg/(m2·s). The heat transfer performance is better at larger mass flux and lower operating pressures

    Effect of Different Zigzag Channel Shapes of PCHEs on Heat Transfer Performance of Supercritical LNG

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    The channels of a printed circuit heat exchanger (PCHE) can have different shapes, and the zigzag channel shape is one of the most widely used because of the relatively simple manufacturing process and low cost. However, the heat transfer enhancement of a zigzag channel is at the expense of increasing the pressure drop. In this paper, new channel shapes of a PCHE, i.e., a zigzag with an inserted straight channel and a zigzag channel with radian, were numerically investigated, with the aim of improving the heat transfer and reducing the pressure drop of supercritical LNG using the SST κ-ω model. The local and total pressure drop and heat transfer performance of supercritical LNG in a zigzag channel, zigzags with 1–5 mm inserted straight channels, and a zigzag channel with radian were analyzed by varying the mass flow rate from 1.83 × 10−4 to 5.49 × 10−4 kg/s. Performance evaluation criteria (PEC) were applied to compare the overall heat transfer performance of the zigzags with 1–5 mm inserted straight channels and a zigzag channel with radian to the zigzag channel of a PCHE. The maximum pressure drop for the zigzag channel was twice the minimum pressure drop for the zigzag channel with radian, while the convective heat transfer coefficient of the zigzag with a 4 mm inserted straight channel was higher, which was 1.2 times that of the zigzag channel with radian with the smallest convective heat transfer coefficient. The maximum value of the PEC with 1.099 occurred at a mass flow rate of 1.83 × 10−4 kg/s for the zigzag with a 4 mm inserted straight channel, while the minimum value of the PEC with 1.021 occurred at a mass flow rate of 5.49 × 10−4 kg/s for the zigzag with a 1 mm inserted straight channel. The zigzag with a 4 mm inserted straight channel had the best performance, as it had a higher PEC value at lower mass flow rates

    Enhanced Microwave-Absorbing Property of Honeycomb Sandwich Structure with a Significant Interface Effect

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    Honeycomb sandwich structures (HSSs) are excellent candidates for light and efficient microwave-absorbing materials. In this work, we design an HSS using SiO2 fiber-reinforced epoxy resin (SiO2f/ER) composites as both the top and bottom layers to improve the impedance matching with free space. Target dielectric properties of the honeycomb and coated lossy material of the HSS were calculated based on the multilayer transmission line theory, metal backplane model, and homogenization theory. In addition, the interface effect between the SiO2f/ER and honeycomb of the HSS was discussed theoretically, experimentally, and numerically, indicating a 1–4% contribution of microwave absorption resulting from the interface. By analyzing the equivalent resistance, equivalent capacitance, as well as equivalent inductance, the enhanced microwave absorption of HSS is attributed to the formation of the interfacial transition zone, which benefits both impedance matching and electromagnetic loss

    Study of the Influence of Ventilation Pipeline Setting on Cooling Effects in High-Temperature Mines

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    The high-temperature environment is a major factor that affects deep mining. Cooling has become a major expense, accounting for up to 25% of the total energy consumption of such mines. To address methods of cooling and the cooling cost, this paper studies the influence of the ventilation duct layout on the cooling effect. Six models were created in ICEM-CFD (3D modeling software), and the influence of cold airflow diffusion on the temperature of the mine environment was numerically simulated using ANSYS Fluent. Under the condition of the same ventilation volume, two models utilizing single pipe and double pipe scenarios were established, and six points were selected as the pipeline suspension position, forming six ventilation duct models. The cooling effect of each model was evaluated by analyzing the average temperature of the roadway section, the three-dimensional distribution of the roadway temperature and the velocity streamline of the whole roadway. The results show that the double-tube model has greater advantages than the single-tube model does, due to its superior local temperature, average temperature of the cross-section, range below 303 K, temperature uniformity and local wind speed. Among the models, model 4 (diameter of 0.5 m, 1.9 m away from the bottom of the roadway and 2.4 m away from the center of the circle) is the best pipeline layout scheme for comprehensive temperature values, roadway temperature uniformity and other factors. The average temperature is 299.3 K within 8 m from the mining face, which is 1.66 K lower than that of the single tube model. This configuration will increase the comfort of the mining environment and reduce cooling costs. These results can provide a reference for ventilation duct layouts of roadways in high temperature mines
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