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Observer canonical form based robust fault detection and estimation for hyperbolic spatiotemporal dynamic systems

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IET Cyber-Systems and Robotics 2020年第4期2卷 168-180页

作者： xiaodong xu Yuncheng Du Stevan Dubljevic McKetta Department of Chemical Engineering University of Texas at AustinAustinTX 78712USA Department of Chemical and Biomolecular Engineering Clarkson UniversityPostdamP.O.Box 5705USA Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaT6G 2V4Canada

In this study,the authors propose a novel state and a fault estimation scheme for a class of hyperbolic spatiotemporal dynamic systems in the presence of unknown external *** consider the occurrence of multiplicative actuator and sensor *** detail,they consider two cases of fault occurrence:(i)only one type(actuator or sensor)of fault happens;(ii)two types of faults occur *** study discusses the fault detectability conditions by proposing a fault detection *** complete the estimation problem,three difficulties arise:(i)no prior information shows the type of faults;(ii)the observer design is non-linear due to multiplication between plant signals(state or input)and unknown fault parameters;(iii)only one boundary measurement is *** convert the original faulty plant into its observer canonical *** proposing two filters based on the resulting observer canonical form,they develop novel parameter update laws for fault parameter *** the proposed update laws,the true state of the faulty plant can be estimated by the proposed *** selecting appropriate Lyapunov functions,they prove that estimation error of state and fault parameters exponentially decays to an arbitrarily small neighbourhood of zero despite unknown external disturbance.

关键词： estimation. estimation canonical

Storage and computing resource enabled joint virtual resource allocation with Qo S guarantee in mobile networks

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Science China(Information Sciences) 2017年第4期60卷 49-59页

作者： xiaodong xu Jiaxiang LIU Wenwan CHEN Yanzhao HOU Xiaofeng TAO National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications

Virtualization is the trend for the future mobile networks. With the advantage of virtualization,we can abstract the physical mobile network into the virtual network function(VNF) and design the network without the details. In this paper, we focus on the virtualization of the physical resources so that the resource allocation scheme considers not only the time-varying characteristic of wireless channels but also the amount of storage and computing resources. Virtual resources are composed of radio, storage and computing resources based on the virtualization technology. Since the cloud radio access network(C-RAN) is a successful paradigm to introduce computing resources into mobile networks, we investigate the virtual resource allocation scheme in the C-RAN architecture. With the content caching technology, we introduce the storage resources into joint resource allocation scheme further. In order to evaluate the performance of proposed scheme, we choose the effective capacity as the metric to include the influence of service latency. The purpose of the optimization problem is maximizing the system effective capacity with constraints of radio, storage and computing *** is simplified and converted into a convex problem solved by the subgradient method. Simulation results are provided to demonstrate performance gain of the effective capacity based joint resource allocation scheme.

关键词： virtualization resource allocation cache computing resource effective capacity C-RAN

A low-floor bit-mapping scheme for LDPC coded BICM for 5G and beyond systems

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Science China(Information Sciences) 2023年第10期66卷 263-277页

作者： Mingyang ZHU Ming JIANG Chunming ZHAO Lijie HU xiaodong xu National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories China Mobile Research Institute

This paper proposes a low-floor bit-mapping(LFBM) scheme for bit-interleaved coded modulation(BICM) systems to meet more stringent quality of service requirements of 5G and beyond. For highefficiency transmissions, we consider the 5G low-density parity-check codes with high-order 2m-quadrature amplitude modulations(QAMs). The proposed LFBM scheme overcomes plenty of trapping sets induced by the bit interleaver, which focuses on the waterfall performance too aggressively. When the high-order QAM is used, the row-column interleaver specified by the 5G standard is such a bit interleaver. The LFBM scheme only optimizes the rule of mapping an m-bit tuple output by the row-column interleaver to a modulation symbol, rather than the entire bit interleaver. Therefore, the optimized bit mapper is actually an m-bit permutation module concatenated with the original bit interleaver employed in the current 5G BICM *** simulation results confirm that the LFBM scheme can lower the error floor of the 5G BICM system by approximately two orders of magnitude, while with negligible performance loss in the waterfall region.

关键词： bit-interleaved coded modulation low-density parity-check codes error floors bit mapping high-order modulation

Effects of extracellular calmodulin on pollen germination and tube growth

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Chinese Science Bulletin 1998年第2期43卷 143-146页

作者： Ligeng Ma xiaodong xu Sujuan Cui Daye Sun Hebei Normal Univ Mol Cell Biol Lab Shijiazhuang 050016 Peoples R China

The effects of calmodulin (CaM) antagonist W7_agarose, anti_CaM serum and exogenous purified CaM on pollen germination and tube growth of Forsythia suspensa were studied. The pollen germination and tube growth were inhibited or completely stopped by CaM antagonist W7_agarose. The addition of exogenous purified CaM stimulated pollen germination and tube growth, whereas the same amount of bovine serum albumin (BSA) had no effect. The inhibitory effects caused by W7_agarose and anti_CaM serum could be reversed completely by the addition of exogenous purified CaM. The tube growth of germinated pollen was also inhibited or completely stopped by W7_agarose. The results suggest that endogenous extracellular CaM initiates pollen germination and tube growth, whereas exogenous CaM enhances the above processes.

关键词： extracellular calmodulin Forsythia suspensa pollen germination pollen tube growth.

Design Framework of Unsourced Multiple Access for 6G Massive IoT

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China Communications 2024年第1期21卷 1-12页

作者： Chunlin Yan Siying Lyu Sen Wang Yuhong Huang xiaodong xu China Mobile Communication Research Institute Beijing 100053China ZGC Institute of Ubiquitous-X Innovation and Applications Beijing 100080China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical solutions.A rather complete design of unsourced multiple access is proposed in which two key parts:a compressed sensing module for active user detection,and a sparse interleaver-division multiple access(SIDMA)module are simulated side by side on a same platform at balanced signal to noise ratio(SNR)operating *** a proper combination of compressed sensing matrix,a convolutional encoder,receiver algorithms,the simulated performance results appear superior to the state-of-the-art benchmark,yet with relatively less complicated processing.

关键词： channel coding compressed sensing massive Internet-of-Things(IoT) sparse interleaverdivision multiple access(SIDMA) the sixth generation(6G)mobile communications unsourced multiple access

Intellicise communication system: model-driven semantic communications

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The Journal of China Universities of Posts and Telecommunications 2022年第1期29卷 2-12页

作者： Zhang Ping xu xiaodong Dong Chen Han Shujun Wang Bizhu State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

As one of the critical technologies for the 6 th generation mobile communication system(6 G) mobile communication systems, artificial intelligence(AI) technology will provide complete automation for connecting the virtual and physical worlds. In order to construct the future ubiquitous intelligent network, people are beginning to rethink how mobile communication systems transmit and exploit intelligent information. This paper proposes a new communication paradigm, called the Intellicise communication system: model-driven semantic communication. Intellicise communication system is built on top of the traditional communication system and innovatively adds a new feature dimension on top of the traditional source coding, which enables the communication system to evolve from the traditional transmission of bit to the transmission of "model". Like the semantic base(Seb) for semantic communication, the model is considered as the new feature obtained from the joint source-channel coding. The sink node can re-construct the original signal based on the received model and the encoded sequence. In addition, the performance evaluation metrics and the implementation details of the Intellicise communication system are discussed in this paper. Finally, preliminary results of model-driven image transmission in the Intellicise communication system are presented.

关键词： Intellicise communication system semantic communications model driven the 6th generation mobile communication system artificial intelligence

Sample-Efficient Deep Reinforcement Learning with Directed Associative Graph

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China Communications 2021年第6期18卷 100-113页

作者： Dujia Yang Xiaowei Qin xiaodong xu Chensheng Li Guo Wei University of Science and Technology of China Hefei 230026China CAS Key Laboratory of Wireless-Optical Communications Hefei 230027China

Reinforcement learning can be modeled as markov decision process *** consequence,the interaction samples as well as the connection relation between them are two main types of information for ***,most of recent works on deep reinforcement learning treat samples independently either in their own episode or between *** this paper,in order to utilize more sample information,we propose another learning system based on directed associative graph(DAG).The DAG is built on all trajectories in real time,which includes the whole connection relation of all samples among all *** planning with directed edges on DAG,we offer another perspective to estimate stateaction pair,especially for the unknowns to deep neural network(DNN)as well as episodic memory(EM).Mixed loss function is generated by the three learning systems(DNN,EM and DAG)to improve the efficiency of the parameter update in the proposed *** show that our algorithm is significantly better than the state-of-the-art algorithm in performance and sample efficiency on testing ***,the convergence of our algorithm is proved in the appendix and its long-term performance as well as the effects of DAG are verified.

关键词： directed associative graph sample efficiency deep reinforcement learning

A Frameless Network Architecture for the Way Forward of C-RAN

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China Communications 2016年第6期13卷 154-166页

作者： xiaodong xu Zhao Sun xun Dai Xiaofeng Tao Ping Zhang National Engineering Laboratory for Mobile Network Security Beijing University of Posts and Telecommunications

The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.

关键词： C-RAN frameless network architecture user-centric control plane and user plane adaptation centralized radio resource management optimization

Key points of investigation and analysis on traffic accidents involving intelligent vehicles

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Transportation Safety and Environment 2021年第4期3卷 46-56页

作者： Quan Yuan Yong Peng xiaodong xu Xinghua Wang State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic and Transportation EngineeringCentral South UniversityChangsha 410075China Fada Institute of Forensic Medicine and Science Beijing 100085China

Intellectualization is regarded as the future mainstream development trend of the automobile *** automation level of intelligent vehicles is relatively low so far,and the road traffic system will be in a mixed state of non-autonomous vehicles and vehicles with different levels of automation for a long ***,the road traffic system will be more complex with more diverse *** paper analysed the characteristics and causal factors of intelligent vehicle *** on the problems existing in investigation,analysis and liability identification of intelligent vehicle accident,the study proposed a preliminary accident investigation framework and method,summarized the key points of accident analysis from the perspectives of technical defects,information security and passive safety,and specified the liability subjects for intelligent vehicle accidents and their corresponding legal *** results from this study contributed to the development of intelligent vehicle accident investigation and disposal,and provided the reference for the improvement of vehicle safety and accident prevention.

关键词： intelligent vehicle accident investigation automated driving liability identification