Liquid hydrogen (LH2) is a high-efficiency cryogenic propellant extensively used in the aerospace industry due to its superior specific impulse and energy density. Despite its advantages, managing LH2 in orbit present...
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This study successfully applies the spatiotemporal transformer-based model to sea surface height anomaly prediction task. An improved ResNet autoencoder, named SW-GD Autoencoder, is proposed based on Sliced-Wasserstei...
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Auxetic metamaterials,which exhibit the negative Poisson’s ratio(NPR)effect,have found wide applications in many engineering ***,their high porosity inevitably weakens their bearing capacity and impact *** improve th...
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Auxetic metamaterials,which exhibit the negative Poisson’s ratio(NPR)effect,have found wide applications in many engineering ***,their high porosity inevitably weakens their bearing capacity and impact *** improve the energy absorption efficiency of auxetic honeycombs,a novel vertex-based hierarchical star-shaped honeycomb(VSH)is designed by replacing each vertex in the classical star-shaped honeycomb(SSH)with a newly added self-similar *** analytical model is built to investigate the Young’s modulus of VSH,which shows good agreement with experimental results and numerical *** in-plane dynamic crushing behaviors of VSH at three different crushing velocities are investigated,and empirical formulas for the densification strain and plateau stress are *** results reveal more stable deformation modes for VSH,attributed to the addition of self-similar star-shaped ***,compared with SSH under the same relative densities,VSH exhibits better specific energy absorption and higher plateau ***,VSH is verified to be a better candidate for energy absorption while maintaining the auxetic *** study is expected to provide a new design strategy for auxetic honeycombs.
With the rapid advancement of urban modernization and the sustainable development of economy, the problems of driving difficulty and parking difficulty are increasingly prominent in large, medium and small cities. In ...
With the rapid advancement of urban modernization and the sustainable development of economy, the problems of driving difficulty and parking difficulty are increasingly prominent in large, medium and small cities. In order to alleviate the contradiction between urban space and vehicle growth rate and improve the utilization efficiency of parking resources, based on the roadside parking data of Nanshan District in Shenzhen City, this paper combines the time series data visualization method and geospatial data visualization method in multi-dimensional data visualization, and adopts the mode of view collaborative interaction to design the intelligent roadside parking collaborative interactive visualization system. The system integrates multisource data, displays roadside parking data information in an all-round way, supports exploratory analysis of roadside parking data characteristics and laws, and helps to understand parking demand and parking distribution at different times and regions. It provides decision support for optimizing parking resource allocation and roadside parking management.
The growing use of bicycles and the increasing frequency of accidents underscore the need for an in-depth investigation into bicyclists' kinematics and injuries. This study aims to collect and analyse bicyclists&#...
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As an important problem in the field of computer vision, facial expression recognition has been widely used in many fields such as human-computer interaction and emotion recognition. This paper proposes a dual-branch ...
As an important problem in the field of computer vision, facial expression recognition has been widely used in many fields such as human-computer interaction and emotion recognition. This paper proposes a dual-branch parallel facial expression recognition network that integrates Convolutional Neural Network (CNN) and Transformer. By consolidating local and global information obtained from the dual branches, the network effectively combines subtle local variations and overall contextual features of facial expressions. The fused feature representation demonstrates enhanced representativeness and discriminative power, leading to a notable improvement in facial expression recognition accuracy. In addressing the challenges posed by inter-class similarity and annotation ambiguity, the Erasing Attention Consistency (EAC) mechanism is employed. This mechanism effectively prevents the model from memorizing noisy samples, thereby enhancing robustness against noisy labels. Additionally, the focal loss function is utilized to rectify imbalances within data samples. Experiments conducted on RAF-DB datasets with labels containing noise reveal that the proposed methodology achieves accuracies of 87.65% and 86.05% at 10% and 20% noise rate, respectively. This substantiates the effectiveness of the proposed approach.
With the continuous development of the Internet of Things (IoT) technology, the large number of messages generated by the increasing number of IoT devices has brought new challenges to MQTT servers. Due to the need fo...
With the continuous development of the Internet of Things (IoT) technology, the large number of messages generated by the increasing number of IoT devices has brought new challenges to MQTT servers. Due to the need for timely forwarding of MQTT messages, the latency of message reception and forwarding will also increase when there are too many clients connected to the server and message publishing and subscription activities are too frequent. In response to this issue, this paper proposes an MQTT subscription tree optimization method that combines hash tables and trie trees. Then, this method is used to implement the subscription tree module of a simple MQTT server, and its performance is compared and analyzed with several other subscription tree implementation methods. The final experimental results show that when a large number of clients connect to the server and frequently publish messages or subscribe to topics, the method proposed in this paper can reduce message forwarding latency, achieve fast message routing, and improve the efficiency of server message forwarding.
Personas, a user characterisation, have been widely used in requirements engineering (RE) to enhance the understanding of end-users and their needs. However, the persona generation process is time-consuming and demand...
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Currently, the search for malicious code in information systems is relevant. The analysis showed that existing static analyzers detect vulnerabilities in the code, but not malicious code, as a result of which it was d...
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ISBN:
(数字)9798331511241
ISBN:
(纸本)9798331511258
Currently, the search for malicious code in information systems is relevant. The analysis showed that existing static analyzers detect vulnerabilities in the code, but not malicious code, as a result of which it was decided to create a new static analyzer with zero false positives, which will not only search for malicious code, but also indicate its location. A formalized representation of the task of detecting malicious code based on static analysis using set theory based on the introduction of a function that matches each element with a maliciousness factor is proposed. A technique for detecting malicious code in the source code based on lexical, semantic and static analysis has been developed. An experimental study has shown that the accuracy of detecting malicious code has increased by three percent, and the F1 measure - by five percent, compared to the best similar tool, which indicates a more effective performance of the task of detecting malicious code by the developed algorithm compared to analogs.
In order to study the extraction and acceleration mechanism of the dual-stage grid,a three-dimensional model based on the Particle-In-Cell/Monte Carlo Collision(PIC/MCC)method is ***-stage grid ion thruster is a new t...
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In order to study the extraction and acceleration mechanism of the dual-stage grid,a three-dimensional model based on the Particle-In-Cell/Monte Carlo Collision(PIC/MCC)method is ***-stage grid ion thruster is a new type of electrostatic ion thruster,which can break through the limitations of traditional gridded ion thrusters,and greatly improve the specific *** high performance also makes the grid sensitive to operating *** this paper,the influence of grid parameters on xenon ion thruster’s performance in a wide range is systematically simulated,and the optimal operating condition is *** the over-focusing of the plume,and the transparency of the screen grid are improved,and the grid corrosion is reduced through simulation *** specific impulse under the given working conditions is 9877.24 s and the thrust is 7.28 *** on the simulation optimization,the limitation of the dual-stage grid is *** grid performs well under high voltage conditions(>3000 V)but not well under low voltage conditions(<2000 V).Finally,since argon is cheaper and more advantageous in future engineering applications,the plasma distribution and grid extraction ability under xenon and argon are analyzed and compared to study the flexibility of the dual-stage grid ion *** simulation results show that a set of optimal parameters is only applicable to the corresponding propellant,which needs to be optimized for different propellant types.
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