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arXiv 2021年

作者： Wu, Yueming Dou, Shihan Zou, Deqing Yang, Wei Qiang, Weizhong Jin, Hai National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Hubei Engineering Research Center on Big Data Security School of Cyber Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Shanghai Key Laboratory of Intelligent Information Processing School of Computer Science Fudan University Shanghai200433 China University of Texas at Dallas Dallas United States National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Cluster and Grid Computing Lab School of Computer Science and Technology Huazhong University of Science and Technology Wuhan430074 China

Due to its open-source nature, Android operating system has been the main target of attackers to exploit. Malware creators always perform different code obfuscations on their apps to hide malicious activities. Features extracted from these obfuscated samples through program analysis contain many useless and disguised features, which leads to many false negatives. To address the issue, in this paper, we demonstrate that obfuscation-resilient malware family analysis can be achieved through contrastive learning. The key insight behind our analysis is that contrastive learning can be used to reduce the difference introduced by obfuscation while amplifying the difference between malware and other types of malware. Based on the proposed analysis, we design a system that can achieve robust and interpretable classification of Android malware. To achieve robust classification, we perform contrastive learning on malware samples to learn an encoder that can automatically extract robust features from malware samples. To achieve interpretable classification, we transform the function call graph of a sample into an image by centrality analysis. Then the corresponding heatmaps can be obtained by visualization techniques. These heatmaps can help users understand why the malware is classified as this family. We implement IFDroid and perform extensive evaluations on two datasets. Experimental results show that IFDroid is superior to state-of-the-art Android malware familial classification systems. Moreover, IFDroid is capable of maintaining a 98.4% F1 on classifying 69,421 obfuscated malware samples. © 2021, CC0.

关键词： Android (operating system)

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design of lossless snubber circuit for phase-shifted full-bridge converter

Design of lossless snubber circuit for phase-shifted full-br...

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2020 International Conference on Applied Physics and Computing, ICAPC 2020

作者： Ji, Shengxian Jie, Guisheng Gao, Shan Wang, Hengli Wang, Ruitian Liu, Xiaohu National key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan430033 China College of Electrical Engineering Naval University of Engineering Wuhan430033 China

In the phase-shifted full-bridge circuit, the voltage spike caused by the hard turn-off of the switch tube increases the voltage stress of the switching device. Due to the existence of energy-consuming components such as resistance in the traditional absorption circuit, the efficiency is not always high. Based on the RCD snubber circuit, a low-loss absorption circuit is designed in this paper. This circuit absorbs voltage spikes through an absorption capacitor, and then slowly releases energy through an oscillating circuit consisting of current-limiting inductance, stray inductance, and absorption capacitance. The current-limiting inductance reduces the current stress of the blocking diode effectively, which can be achieved with the absorption not being affected and the power loss being reduced. Finally, the absorption effect and energy loss of the new low-loss absorption circuit and the commonly used RCD circuit were simulated and compared in PSpice software, and verified its feasibility. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Capacitance

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Accelerated performance degradation test and analysis of high-temperature strain gauges

Accelerated performance degradation test and analysis of hig...

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13th International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering (QR2MSE 2023)

作者： L. Li Z. Wang N. Yang Q. Wu H. Wang Z. Mao K. Ren Q. Wang Y. Wang National Key Laboratory of Strength and Structural Integrity School of Aeronautic Science and Engineering Beihang University Beijing People's Republic of China Shenyang Aircraft Design and Research Institute Shenyang People's Republic of China Institute of Spacecraft System Engineering China Academy of Space Technology Beijing People's Republic of China Navigation Instrument Research Institute Tianjin People's Republic of China Beijing Institute of Control Engineering Beijing People's Republic of China

ISBN: (数字)9781839539275

With the extension of the service time of the structure and the worse service temperature conditions, the drift problem of hightemperature strain gauges gradually becomes prominent. This research aims to address the issue of the drift of measurement results because of the performance degradation of high-temperature strain gauges, and investigate the drift law under different temperatures considering complex service environments. In this paper, a combination of experimental research and theoretical analysis is utilized to design and conduct the accelerated performance degradation test on high-temperature strain gauges. Based on the result of the test, an accelerated performance degradation model is developed using the Wiener process and Arrhenius model. Finally, estimation curves for the average value and percentile value of the performance parameters of the hightemperature strain gauges are obtained, which demonstrates that the established accelerated performance degradation model can reasonably describe the degradation law. Additionally, the established accelerated performance degradation model enables effective analysis and compensation of gauge drift at any temperature.

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Fluorescent Carbon Dots Crosslinked Salix Psammophila Microcrystalline Cellulose Interpenetrating Hydrogel system for Sensitive Detection and Efficient Adsorption of Fe3+

SSRN

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SSRN 2023年

作者： Wang, Boyun Zhong, Yuan Zhang, Wanqi Liu, Zhechen Hu, Zichu Chen, Long Wang, Ximing Zhang, Xiaotao College of Science Inner Mongolia Agricultural University Hohhot010018 China College of Material Science and Art Design Inner Mongolia Agricultural University Hohhot010018 China Inner Mongolia Key Laboratory of Sandy Shrubs Fibrosis and Energy Development and Utilization Hohhot010018 China National Forestry Grassland Engineering Technology Research Center for Efficient Development and Utilization of Sandy Shrub Hohhot010018 China

To combat the contaminating effects of heavy-metal ions on water resources, we prepared blue photonitrogen-doped carbon quantum dots (NCDs) from Salix psammophila (SP) as a raw material, doped them into a microcrystalline cellulose hydrogel, and successfully created a composite hydrogel (NCDs-SP-MCC-gels) for concurrent fluorescence detection and Fe3+ adsorption. The NCDs-SP-MCC-gel was examined for their shape, chemical composition, fluorescence characteristics, and adsorption behaviors. Results demonstrated that the NCD-SP-MCC-gels displayed a broad linear range of Fe3+ fluorescence response (200–1000 mg/L;detection limit = 56.2632 mg/L) and a high adsorption capacity for Fe3+ (610 mg/g). The adsorption data fitted the Langmuir and pseudo-second-order models well. Further research was conducted on Fe3+ detection and adsorption onto the NCD-SP-MCC-gels. This study proposes a green and sustainable way to create a material for the detection and absorption of heavy-metal ions. © 2023, The Authors. All rights reserved.

关键词： Adsorption

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Influence of manufacturing errors of bearing components on rotational accuracy of cylindrical roller bearings

Research Square

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Research Square 2021年

作者： Yu, Yongjian Li, Jishun Xue, Yujun School of Mechatronics Engineering Henan University of Science and Technology Luoyang471003 China Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang471003 China Luoyang LYC Bearings Co. Ltd State Key Laboratory of Aviation Precision Bearings Luoyang471039 China

Understanding the influence of bearing component manufacturing errors and roller number on the rotational accuracy of rolling bearings is crucial in the design of high precision bearings. The rotational accuracy of an assembled bearing is dependent upon roller number and manufacturing error of the bearing components. We propose a model for calculating the rotational accuracy of a cylindrical roller bearing;we experimentally verified the effectiveness of the model in predicting the radial run-out of the inner ring proposed in the previous paper in this series. We sought to define the key contributing factors to the rotational accuracy by studying both the influence of the coupling effect of the roller number and the influence of the manufacturing errors in the inner raceway, outer raceway, and rollers on the motion error. The model and results will help engineers choose reasonable manufacturing tolerances for bearing components to achieve the required rotational accuracy. © 2021, CC BY.

关键词： Rollers (machine components)

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Nutritional quality of interspecific backcross between hybrids of Crassostrea gigas×C. angulata and their two parental species

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Journal of Oceanology and Limnology 2025年第3期 1022-1035页

作者： Chenchen WEI Luping WANG Xinfeng SUN Wei WANG Guofan ZHANG Li LI Rihao CONG College of Life Sciences Qingdao Agricultural University CAS and Shandong Province Key Laboratory of Experimental Marine Biology Center for Ocean Mega-Science Institute of Oceanology Chinese Academy of Sciences College of Fisheries and Life Science Dalian Ocean University Laboratory for Marine Fisheries Science and Food Production Processes National and Local Joint Engineering Laboratory of Ecological Mariculture Institute of Oceanology Chinese Academy of Sciences Laboratory for Marine Biology and Biotechnology Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture Institute of Hydrobiology Shandong Technology Innovation Center of Oyster Seed Industry The Innovation of Seed Design Chinese Academy of Sciences

Oysters are of the most economically important bivalves worldwide. It has high nutritional value and is regarded as a good source of proteins, lipids, glycogen, and amino acids. C. gigas and *** are allopatric congeneric dominant oysters that are widely cultivated in the northern and southern coast of China, and have shown remarkable differentiation in the nutritional *** hybridization and backcross of the two species are effective ways to improve the nutritional quality of the oyster. Sixteen progenies were constructed based on a 4×4 diallel crosses among broodstock of C. gigas(G), C. angulata(A) and their hybrids GA(H) and AG(R). The glycogen, fatty acids, and amino acids performance of these progenies were evaluated in 22 months after fertilization. The glycogen content of AA was significantly lower than that of the other 15 progenies(P<0.05), while only the GH progeny was significantly higher than the GG(P<0.05), with a heterosis value of 21.06%. The backcross progenies GR exhibited significantly higher saturated fatty acids, eicosapentaenoic acid(EPA), and polyunsaturated fatty acids(PUFAs) content than those of GG(P<0.05), and did not show significant differences from AA. The AA showed significantly higher content of total amino acids(TAAs) than GG(P<0.05). The AH progeny displayed significantly higher taurine(Tau) content than GG(P<0.05), and the heterosis value was 27.88%. Therefore, the backcross breeding was shown an effective way to improve the glycogen, fatty acids, and TAAs of GG, and the glycogen of AA. This study provided useful information to characterize the benefits of backcrossing in nutritional quality, which will facilitate the production of differentiated products and increase the efficiency of the oyster industry.

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Study on numerical model of vortex shedding for three-way pipe 48

Study on numerical model of vortex shedding for three-way pi...

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48th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2019 MADRID

作者： Liu, Shuai Feng, ZhiPeng Wu, WanJun Jiang, XiaoZhou Huang, Xuan Qi, HuanHuan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China. No. 328 Changshun Avenue Shuangliu Chengdu China

ISBN: (纸本)9788487985317

The three-way pipe vortex shedding phenomenon is the main excitation source for pipe vibration, which can lead to the generation of acoustic resonance. The existing researches mainly focus on air and wet steam, however the researches on water medium is rare. In this paper, the formation mechanism of vortex shedding for three-way pipe under water medium is studied, and the influence of turbulence model, water compressibility, boundary layer and model size is discussed. A more accurate simulation model is established, The suggestions for the establishment of the three-way pipe vortex shedding simulation model are given according to the simulation results. © INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering. All Rights Reserved.

关键词： Vortex shedding

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Copula method of the kinematic accuracy of cylindrical roller bearing

Research Square

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Research Square 2021年

作者： Li, Lihong Xue, Yujun Li, Jishun Vehicles & Transportation Engineering Institute Henan University of Science and Technology Luoyang471003 China Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang471003 China State Key Laboratory of Aviation Precision Bearings Luoyang LYC Bearings Co. Ltd. Luoyang471039 China

The kinematic accuracy of cylindrical rollers bearing isn’t only influenced by the dimensional and form precision of its parts, but also more influenced by the cooperation among them. For cylindrical rollers bearing, the main indices of the kinematic accuracy are the ending beat and the radial run out of bearings. There must be dependent relationship between the cooperative action among the parts of bearings and the ending beat or the radial run out of bearings. This relationship is hardly expressed by mathematical formula. However, because the parts dimension deviation and the run out of bearings follow statistic law and have their distribution characteristics, while the copula joint distribution function can connect the run out of bearings with multiple parts dimension accuracy, the copula function is introduced to analyze the dependent relationship between bearing parts cooperative action and its kinematic accuracy. Based on the copula function of statistic theory, the kinematic accuracy of bearings can be forecast by parts geometric accuracy. © 2021, CC BY.

关键词： Kinematics

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A Hierarchical Ensemble Learning Framework for Energy-Efficient Automatic Train Driving

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Tsinghua science and technology 2019年第2期24卷 226-237页

作者： Guohua Xi Xibin Zhao Yan Liu Jin Huang Yangdong Deng CRRC Corporation Limited School of Software and Key Laboratory for Information System Security Ministry of Education (KLISS)/Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University

Railway transportation plays an important role in modern society. As China's massive railway transportation network continues to grow in total mileage and operation density, the energy consumption of trains becomes a serious concern. For any given route, the geographic characteristics are known a priori, but the parameters(e.g., loading and marshaling) of trains vary from one trip to another. An extensive analysis of the train operation data suggests that the control gear operation of trains is the most important factor that affects the energy consumption. Such an observation determines that the problem of energy-efficient train driving has to be addressed by considering both the geographic information and the trip parameters. However, the problem is difficult to solve due to its high dimension, nonlinearity, complex constraints, and time-varying characteristics. Faced with these difficulties, we propose an energy-efficient train control framework based on a hierarchical ensemble learning approach. Through hierarchical refinement, we learn prediction models of speed and gear. The learned models can be used to derive optimized driving operations under real-time requirements. This study uses random forest and bagging – REPTree as classification algorithm and regression algorithm, respectively. We conduct an extensive study on the potential of bagging, decision trees, random forest, and feature selection to design an effective hierarchical ensemble learning framework. The proposed framework was testified through simulation. The average energy consumption of the proposed method is over 7% lower than that of human drivers.

关键词： machine learning energy efficiency train driving system feature selection ensemble learning

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Time-varying Characteristics of mmWave Channel based on the Clustered Sparsity Model

Time-varying Characteristics of mmWave Channel based on the ...

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IEEE Conference on Vehicular technology (VTC)

作者： Lijun Yang Haitao Lu Xinchao Ge Zhixin Sun Pan Cao School of Internet of Things Nanjing University of Posts and Telecommunications Nanjing China RAN System Design Dept. ZTE Corporation Shenzhen China Shenzhen Key Laboratory of 5G RAN Security Technology Research and Application Shenzhen China School of Modern Posts Nanjing University of Posts and Telecommunications Nanjing China School of Physics Engineering and Computer Science University of Hertfordshire Hatfield UK

A better understanding of the mmWave channel coherence time will play a significant role in both communication and sensing. Traditional literatures consider that the channel coherence time in mmWave communication will be very short due to high frequency, which makes the channel estimation more difficult. However, we believe that the propagation characteristics of the mmWave channel will affect its coherence time, i.e., channel sparsity may limit its time variability. In this paper, we investigate the time-varying nature of mmWave channel by analyzing its Doppler spread based on the clustered sparsity model. After the derivation of Doppler spectrum DPS and the simulation analysis based on the two-cluster channel, we found that the maximum angle between clusters and the power distribution between clusters are two main factors limiting the Doppler spread. Finally, the realistic mmWave NYUSIM model is used for Doppler spread comparative analysis with Clarke’s model and find that Doppler spread of NYUSIM channel is far less than that estimated based on Clarke’s model. Thus, it is demonstrated that even if the mmWave frequency is high, the clustered sparsity characteristics makes its channel coherence time not as short as thought intuitively, which is meaningful for mmWave vehicular sensing and communication.

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