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A threshold effect of coupling delays on intra-layer synchronization in duplex networks

Science China(Technological Sciences) 2018年第12期61卷 1907-1914页

作者： TANG LongKun LU JunAn Lü JinHu Fujian Province University Key Laboratory of Computation Science School of Mathematical Sciences Huaqiao University Department of Mathematics & Statistics Georgia State University School of Mathematics and Statistics Wuhan University School of Automation Science and Electrical Engineering State Key Laboratory of Software Development Environment and Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University

This paper investigates the impact of inter-layer coupling functions and intra-layer coupling delays on intra-layer synchronization regions and sychronizability. It is found that the inter-layer coupling functions have great influence on intra-layer synchronization regions, as well as on the intra-layer synchronizability. In particular, there exists an inter-layer coupling function such that the inter-layer coupling strength neither improves nor weakens the intra-layer synchronizability. Furthermore, no matter which one of three inter-layer coupling functions is chosen, a small intra-layer delay always keeps the intra-layer synchronized regions almost unchanged, implying that the small delay neither enhances nor suppresses the intra-layer synchronizability. At the same time the delay greatly frustrates the synchronizability in each layer when it is greater than some threshold. Our results may have potential applications for interconnected technological networks where communication delays are inevitably present.

关键词： multiplex network master stability function intra-layer synchronization synchronized region time delay

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An efficient matching method for dispatching autonomous vehicles*

An efficient matching method for dispatching autonomous vehi...

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International Conference on Intelligent Transportation

作者： Ming Li Nan Zheng Xinkai Wu Xiang Huo School of Transportation Science and Engineering Beihang University China Department of Civil Engineering Monash University Australia Beijing Advanced Innovation Center for Big Data and Brain Computing School of Transportation Science and Engineering Beihang University China

ISBN: (纸本)9781538670255

Autonomous vehicles (AVs), as an emerging transportation tool, are widely discussed for improving traffic mobility. Particularly, when combining with prevalent shared transportation modes, i.e., car-sharing and ride-sharing, AVs show promising future. However, the efficiency of searching for an optimal match between shared autonomous vehicles and passengers has long become a critical problem. This research tackles this issue by developing a model which has better efficiency. The essential task is to dispatch vehicles to serve passengers, which is similar to vehicle routing problem. But unlike existing vehicle routing models, our method makes use of the similarity of passengers' demand instead of directly matching vehicles and passengers. In this way, a cluster-based algorithm is proposed to find near-optimal solutions. Numerical experiments on large-size are performed to present the validity of the optimization model and efficiency of the proposed algorithm. Results indicate that the cluster-based algorithm could bring benefit to minimizing the number of vehicles and total travel distance.

关键词： Intelligent transportation systems Conferences

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Same influenza, different responses: Social media can sense a regional spectrum of symptoms

arXiv

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arXiv 2019年

作者： Shan, Siqing Jia, Yingwei Zhaoa, Jichang School of Economics and Management Beihang University Beijing China Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operation Beijing China Beijing Advanced Innovation Center for Big Data and Brain Computing Beijing China

Influenza is an acute respiratory infection caused by a virus. It is highly contagious and rapidly mutative. However, its epidemiological characteristics are conventionally collected in terms of outpatient records. In fact, the subjective bias of the doctor emphasizes exterior signs, and the necessity of face-to-face inquiry results in an inaccurate and time-consuming manner of data collection and aggregation. Accordingly, the inferred spectrum of syndromes can be incomplete and lagged. With a massive number of users being sensors, online social media can indeed provide an alternative approach. Voluntary reports in Twitter and its variants can deliver not only exterior signs but also interior feelings such as emotions. These sophisticated signals can further be efficiently collected and aggregated in a real-time manner, and a comprehensive spectrum of syndromes could thus be inferred. Taking Weibo as an example, it is confirmed that a regional spectrum of symptoms can be credibly sensed. Aside from the differences in symptoms and treatment incentives between northern and southern China, it is also surprising that patients in the south are more optimistic, while those in the north demonstrate more intense emotions. The differences sensed from Weibo can even help improve the performance of regressions in monitoring influenza. Our results suggest that self-reports from Copyright © 2019, The Authors. All rights reserved.

关键词： Social networking (online)

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A Low Noise Operational Amplifier With Cascode Frequency Compensation Technique for Voice Detection and Recognition

A Low Noise Operational Amplifier With Cascode Frequency Com...

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International Conference on Integrated Circuits and Microsystems (ICICM)

作者： Yang Liu Zhaohao Wang Jianlei Yang Weisheng Zhao Beihang-Goertek Joint Microelectronics Institute Qingdao Research Institute Beihang University Beijing China Fert Beijing Research Institute Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing China

This paper proposes a low noise operational amplifier for voice detection and recognition. The transistor level low noise technologies and the cascode frequency compensation are presented in this design. This work has been implemented in a 180 nm CMOS process and simulated with a 2 V power supply, a 200 kΩ resistive load and a 220 pF capacitive load. The proposed amplifier consumes an area of 282 fm x 332 fm and a total quiescent current of 109.258 μA. And it achieves a closed loop gain of 2.96205 dB, a unity gain frequency of 3.18 MHz with 40.2° phase margin and an input integrated noise of -109.585 dBV within 20 Hz - 20 kHz (an input referred noise at 1 kHz of 28.61 nV/sqrt(Hz)).

关键词： Conferences Integrated circuits Micromechanical devices

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Time-varying formation control and disturbance rejection for UAV-UGV heterogeneous swarm system

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2020年 41卷

作者： Zhou, Siquan Dong, Xiwang Li, Qingdong Ren, Zhang School of Automation Science and Electrical Engineering Beihang University Beijing100083 China Science and Technology on Aircraft Control Laboratory Beihang University Beijing100083 China Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing100083 China

This paper studies the time-varying formation control and disturbance rejection problems for heterogeneous UAV-UGV swarm system. The UAV-UGV swarm system is designed to achieve the desired time-varying output formation under unknown external disturbances. First, the kinetic and dynamic mathematical models of each UAV/UGV are established. In addition, the cooperative control models for heterogeneous swarm system are constructed by using the algebraic graph theory. Then, a distributed time-varying output formation controller is designed based on the internal model theory. The distributed formation center estimator and disturbance rejection compensator are designed and added to the formation controller. Third, an algorithm is presented to design the formation control parameters, where the feasibility conditions for achieving the time-varying output formation are given. The stability of the closed-loop UAV-UGV swarm system is proved. Finally, a simulation example is provided to demonstrate the effectiveness of the proposed formation control approach. © 2020, Beihang University Aerospace Knowledge Press. All right reserved.

关键词： Unmanned aerial vehicles (UAV)

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Defending against advanced persistent threat: A risk management perspective 1st

Defending against advanced persistent threat: A risk managem...

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1st International Conference on Science of Cyber Security, SciSec 2018

作者： Zhong, Xiang Yang, Lu-Xing Yang, Xiaofan Xiong, Qingyu Wen, Junhao Tang, Yuan Yan School of Big Data and Software Engineering Chongqing University Chongqing400044 China School of Information Technology Deakin University MelbourneVIC3125 Australia Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing100083 China Department of Computer and Information Science The University of Macau China

ISBN: (纸本)9783030030254

Advanced persistent threat (APT) as a new form of cyber attack has posed a severe threat to modern organizations. When an APT has been detected, the target organization has to develop a response resource allocation strategy to mitigate her potential loss. This paper suggests a risk management approach to solving this APT response problem. First, we present three state evolution models. Thereby we assess the organization’s potential loss. On this basis, we propose two kinds of game-theoretic models of the APT response problem. This work initiates the study of the APT response problem. © Springer Nature Switzerland AG 2018.

关键词： Game theory

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Three-Dimensional Reconstruction Method with Parameter Optimization for Point Cloud Based on Kinect v2

Three-Dimensional Reconstruction Method with Parameter Optim...

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作者： Kai-zhang WANG Tong-kai LU Qi-hang YANG Xi-hao FU Ze-hong LU Bo-lun WANG Xin JIANG Key Laboratory of Mathematics Informatics and Behavioral Semantics and School of Mathematics and Systems Science Beihang University Peng Cheng Laboratory Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC) School of Mathematical Science Peking University

Three-Dimensional(3D) reconstruction is a significant part in the field of computer vision. In this paper, we use Kinect v2 to obtain the 3D point cloud. As a consumer used 3D sensor, Kinect has numerous advantages such as low price, relative high dot per inch(DPI) and frames per second(FPS) and strong robustness. During the experiment, the object was placed on a turntable spinning and stop for every 12°, collecting 30 images of point cloud in total. Then we used Iterated Closest Points(ICP) algorithm to calculate the optimal rotation matrix and translation matrix to match all point cloud into the same coordinate. After that, three algorithms including Statistical Outlier Removal, Movement Least Squares(MLS) and Voxelgrid were used to reduce the noise. At last, we applied greedy projection algorithm to generate the triangulate mesh. During the procession, we observed the relationship between parameters and outcome and drew pictures to have the data more visible, which gave out the optimal parameters in return.

关键词： 3D Reconstruction Parameter optimization Kinect v2

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Asymmetric scattering behaviors of spin wave dependent on magnetic vortex chirality

arXiv

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arXiv 2020年

作者： Zhang, Xue-Feng Shim, Je-Ho Ma, Xiao-Ping Song, Cheng Yu, Haiming Piao, Hong-Guang Hubei Engineering Research Center of Weak Magnetic-Field Detection China Three Gorges University Yichang443002 China Department of Physics College of Science Yanbian University Yanji133002 China School of Materials Science and Engineering Tsinghua University Beijing100084 China Fert Beijing Institute School of Integrated Circuit Science and Engineering Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing100191 China

In this letter, an asymmetric spin wave scattering behaviors caused by vortex chirality are investigated in cross-shaped ferromagnetic system. In the system, four scattering behaviors are found, 1) asymmetric skew scattering, depending on the polarity of vortex core, 2) back scattering (reflection), depending on the vortex core stiffness, 3) side deflection scattering, depending on structural symmetry of the vortex circulation, and 4) geometrical scattering, depending on waveguide structure. The first and second scattering behaviors are attributed to nonlinear topological magnon spin Hall effect related to magnon spin-transfer torque effect, which has value for magnonic exploration and application. Copyright © 2020, The Authors. All rights reserved.

关键词： Chirality

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A Novel Differential System Construction Method for Complex Surface Based on Aerodynamic Design

A Novel Differential System Construction Method for Complex ...

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作者： Dan-lei YE Xin JIANG Guan-ying HUO Cheng SU Ze-hong LU Bo-lun WANG Zhi-ming ZHENG Key Laboratory of Mathematics Informatics and Behavioral Semantics (LMIB) School of Mathematics and Systems Science Beihang University Peng Cheng Laboratory Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC) School of Mathematical Science Peking University

In this paper, a novel complex surface construction method for aerodynamic design is proposed based on differential system. In order to simplify the process of calculating and analyzing the flow field above the surface, we introduce a high-dimensional truncation method of Navier-Stokes equations to transform the complex partial differential system into an ordinary one. Concretely, we excute the Fourier expansion along some selected directions which are called wave vector sets, preserving the local properties of the solutions of Navier-Stokes equations. Further, we use the truncated ordinary differential system to describe the shape of complex surface. Experiments show that our differential system construction method for complex surface dedicated to aerodynamic design has better fitting results than the traditional linear fitting method.

关键词： High-dimensional truncation Navier-Stokes equations Nonlinear ordinary differential system

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Aggregating multiple types of complex data in stock market prediction: A model-independent framework

arXiv

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arXiv 2018年

作者： Wang, Huiwen Lu, Shan Zhao, Jichang School of Economics and Management Beihang University Beijing Advanced Innovation Center for Big Data and Brain Computing Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operations

The increasing richness in volume, and especially types of data in the financial domain provides unprecedented opportunities to understand the stock market more comprehensively and makes the price prediction more accurate than before. However, they also bring challenges to classic statistic approaches since those models might be constrained to a certain type of data. Aiming at aggregating differently sourced information and offering type-free capability to existing models, a framework for predicting stock market of scenarios with mixed data, including scalar data, compositional data (pie-like) and functional data (curve-like), is established. The presented framework is model-independent, as it serves like an interface to multiple types of data and can be combined with various prediction models. And it is proved to be effective through numerical simulations. Regarding to price prediction, we incorporate the trading volume (scalar data), intraday return series (functional data), and investors’ emotions from social media (compositional data) through the framework to competently forecast whether the market goes up or down at opening in the next day. The strong explanatory power of the framework is further demonstrated. Specifically, it is found that the intraday returns impact the following opening prices differently between bearish market and bullish market. And it is not at the beginning of the bearish market but the subsequent period in which the investors’ "fear" comes to be indicative. The framework would help extend existing prediction models easily to scenarios with multiple types of data and shed light on a more systemic understanding of the stock market. Copyright © 2018, The Authors. All rights reserved.

关键词： Forecasting

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