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Design and dynamic analysis of a scissors hoop-rib truss deployable antenna mechanism

Defence technology（防务技术） 2023年第6期24卷 399-413页

作者： Bo Han Xiangkun Li Jian Sun Yundou Xu Jiantao Yao Yongsheng Zhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao066004China Key Laboratory of Advanced Forging&Stamping Technology and Science Ministry of Education of ChinaYanshan UniversityQinhuangdao066004China

As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel *** this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the *** analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one *** and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation *** on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB *** addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole *** mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas.

关键词： Scissors mechanism Deployable antenna Screw theory Kinematic analysis Dynamic analysis

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MixedCache: Enabling Flow Directed Rule-Caching Scheme based on Heterogeneous Cache for OpenFlow 3

MixedCache: Enabling Flow Directed Rule-Caching Scheme based...

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2020 3rd International Conference on Computer Information science and Artificial Intelligence, CISAI 2020

作者： Yang, Jialun Yang, Yi Liu, Jiahao Liu, Rulin Qiao, Peng Wang, Baosheng College of Computer Science and Technology National University of Defense Technology Changsha410073 China Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha410073 China

OpenFlow switches in SDN use Multiple Flow Tables (MFTs) for fine-grained flow control. Commodity switches integrate hardware storage resources such as SRAM and TCAM to store flow tables to achieve high-speed lookups. Many increased flow tables are rapidly exhausting these hardware storage resources, which makes the switches have to balance high-speed search and massive storage. The rule-caching scheme is a popular method to solve this problem, which caches the most commonly used rules into hardware storage resources. The existing rule-caching schemes are based on single hardware storage resources, and they cannot flexibly adjust the caching strategy according to the traffic characteristics. Simultaneously, the deployed commodity switches face the problem of difficulty in changing the size of SRAM and TCAM. This paper innovatively proposes the MixedCache scheme, which makes full use of the hardware storage resources in the switch according to the skewed characteristics of network traffic. MixedCache stores the large flows in SRAM by exact match and stores the small flows in the TCAM by wildcard match. MixedCache does not need to change the size of the deployed switch hardware storage resources, but makes full use of existing resources. Compared with the rule-caching scheme based on the exact match, the cache hit rate can increase by up to 15.61%. Compared with the rule-caching scheme based on the wildcard match, the cache hit rate can increase by up to 29.69%. © Published under licence by IOP Publishing Ltd.

关键词： Static random access storage

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A novel secure inter-domain routing for identifier/locator split network

A novel secure inter-domain routing for identifier/locator s...

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2nd International Conference on Information technology and Management Innovation, ICITMI 2013

作者： Liu, Ya Ping Liu, Zhi Hong Ma, Shi Cong Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology China College of Computer National University of Defense Technology China

ISBN: (纸本)9783037858646

With the rapid development of the Internet, the de facto inter-domain routing protocol, Border Gateway Protocol (BGP), has become very vulnerable to many attacks. For this, several secure inter-domain protocols have been proposed, most of which are focus on addressing the issue of faking AS path, but cannot address other issues, such as violating routing policies, reachability attacks and so on. Based on the concept of identifier/locator split and routing isolation, we have proposed a secure identifier-based inter-domain Routing, SIR [1], which can provide control plane security without using the high overhead mechanism. Then, we here optimize SIR and propose another secure inter-domain routing, Optimized SIR (O-SIR), which introduces a checked path table and records the path which has been checked before in each AS. We present the simulations based on the real world datasets CAIDA and compare the performance between SIR and O-SIR by different deployments and different position of attacks. The results show that O-SIR can reduce 18%-45% communication cost of verifying paths with additional below 0.1% routing table size. © (2013) Trans Tech Publications, Switzerland.

关键词： Routing protocols

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A Multi-Objective Artificial Physics Optimization Algorithm Based on Two-Phase Search 8

A Multi-Objective Artificial Physics Optimization Algorithm ...

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8th International Symposium on Computer science and Intelligent Control, ISCSIC 2024

作者： Zhang, Huihua Xie, Liping Taiyuan University of Science and Technology Shanxi Key Laboratory of Big Data Analysis and Parallel Computing Taiyuan China

ISBN: (纸本)9798350380286

Aiming at the problems of insufficient utilization of information about elite particles in archive and instability of particle motion in the population in the multi-objective artificial physics optimization algorithm (MOAPO) in solving multiobjective optimization problems, A multi-objective artificial physics optimization algorithm based on two-phase search (TPMOAPO) is proposed. To begin with, the algorithm improves the calculation of the mass of particles, so that the strength and weakness of the particles can be accurately transformed into the corresponding masses while improving the efficiency of particle mass calculation. Next, a two-phase search strategy is proposed, which makes the algorithm have strong exploration ability in the first phase, and the second phase gradually enhances the exploitation capability with iterations, which solves the problem of instability motion of particles in the search process. Finally, the simulated binary crossover (SBX) and polynomial-based mutation (PM) operators are adopted in the archive to further enhance the search capability of the algorithm. For verifying the performance of TP-MOAPO, 21 benchmark functions were selected to compare with the classical multi-objective particle swarm optimization algorithms: MOPSO, dMOPSO, SMPSO, MMOPSO, and NMPSO, and the experimental results show the superiority of TP-MOAPO in these functions. © 2024 IEEE.

关键词： Optimization algorithms

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SSSP on GPU without atomic operation 2nd

SSSP on GPU without atomic operation

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2nd International Conference on Human Centered Computing, HCC 2016

作者： Wang, Feng Zhu, Liehuang Zhang, Changyou School of Computer Science and Technology Beijing Institute of Technology Beijing100081 China Laboratory of Parallel Software and Computational Science Institute of Software Chinese Academy of Science Beijing100190 China

ISBN: (纸本)9783319318530

Graph is a general theoretical model in many large scale data-driven applications. SSSP (Single Source Shortest Path) algorithm is a foundation for most important algorithms and applications. GPU remains its mainstream station in high performance computing with heterogeneous architecture computers. Because of the high parallelization of the GPU threads, the distances of the vertices of the GPU are updated by atomic operations to avoid the read and write errors. Most atomic operations are unnecessary since the read-write conflicts are rare in large graph. However, without atomic operations the result accuracy can’t be guaranteed. The atomic operations take large part of the running time of the program. To improve the performance of SSSP on GPU, we proposed an algorithm with data block iterations instead of atomic operations. The algorithm not only gets a high speed-up but also guarantees the accuracy of the result. Experimental results show that this SSSP algorithm gained a speedup of three times than the serial algorithm on CPU and more than ten times than the parallel algorithm on GPU with atomic operation. © Springer International Publishing Switzerland 2016.

关键词： Graphics processing unit

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Speculative symbolic execution

Speculative symbolic execution

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2012 IEEE 23rd International Symposium on Software Reliability Engineering, ISSRE 2012

作者： Zhang, Yufeng Chen, Zhenbang Wang, Ji National Laboratory for Parallel and Distributed Processing Department of Computing Science National University of Defense Technology Changsha China

ISBN: (纸本)9780769548883

Symbolic execution is an effective path oriented and constraint based program analysis technique. Recently, there is a significant development in the research and application of symbolic execution. However, symbolic execution still suffers from the scalability problem in practice, especially when applied to large-scale or very complex programs. In this paper, we propose a new fashion of symbolic execution, named Speculative Symbolic Execution (SSE), to speed up symbolic execution by reducing the invocation times of constraint solver. In SSE, when encountering a branch statement, the search procedure may speculatively explore the branch without regard to the feasibility. Constraint solver is invoked only when the speculated branches are accumulated to a specified number. In addition, we present a key optimization technique that enhances SSE greatly. We have implemented SSE and the optimization technique on Symbolic Pathfinder (SPF). Experimental results on six programs show that, our method can reduce the invocation times of constraint solver by 20.7% to 48.7% (with an average of 29.9%), and save the search time from 23.6% to 43.6% (with an average of 30%). © 2012 IEEE.

关键词： Java programming language

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Big Data Mining of Maritime Shipping Flows Based on Dependency Relationships 9

Big Data Mining of Maritime Shipping Flows Based on Dependen...

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9th International Conference on Intelligent Computing and Signal Processing, ICSP 2024

作者： Fu, Yude Li, Xiang Lu, Xiongyi Yu, Mengjun Huangpeng, Qizi Duan, Xiaojun College of Science National University of Defense Technology Changsha China National Research Center of Parallel Computer Engineering and Technology Beijing China

ISBN: (纸本)9798350376548

This research utilizes higher-order dependency relationships for the modeling of higher-order dependency networks from voluminous maritime flow data and introduces higher-order dependency mining to uncover critical port information in the China-Southeast Asia region as well as the coopetition relationships between ports. Analysis of maritime data from the years 2018 and 2023 indicates that global ports maintain stability and competitiveness through their evolution, with Singapore serving as the central hub connecting China and Southeast Asia. Subsequent analysis employing dependency paths indicates that in recent years, the dependency relationships among ports between China and Southeast Asia have achieved higher orders and greater complexity. © 2024 IEEE.

关键词： competition and cooperation dependency relationships flow data maritime network

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Optimizing Yinyang K-Means Algorithm on ARMv8 Many-Core CPUs 22nd

Optimizing Yinyang K-Means Algorithm on ARMv8 Many-Core CPU...

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22nd International Conference on Algorithms and Architectures for parallel Processing, ICA3PP 2022

作者： Zhou, Tianyang Wang, Qinglin Yin, Shangfei Hao, Ruochen Liu, Jie Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha410073 China School of Computer Science National University of Defense Technology Changsha410073 China

ISBN: (纸本)9783031226762

K-Means algorithm is one of the most common clustering algorithms widely applied in various data analysis applications. Yinyang K-Means algorithm is a popular enhanced K-Means algorithm that avoids most unnecessary calculations using triangle inequality. However, Yinyang K-Means algorithm is time-consuming when the problem size is large. Due to the influence of performance and energy-efficiency, ARM CPUs have appeared in high performance computing. Therefore, it is very interesting to accelerate Yinyang K-Means algorithm on ARM CPUs. In this paper, we propose an efficient parallel implementation of Yinyang K-Means algorithm on ARMv8 many-core CPUs by means of vectorization, NUMA affinity memory optimization and data layout optimization. The experiment on two ARMv8 many-core CPUs has shown that our implementation can achieve up to 5.6 times faster than the open-source multi-threaded one of Yinyang K-Means algorithm. To the best of our knowledge, this is the first work that studies the optimization of Yinyang K-Means algorithms on ARMv8 CPUs. © 2023, Springer Nature Switzerland AG.

关键词： K-means clustering

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FedEAE: Federated Learning Based Privacy-Preserving Event Argument Extraction 12th

FedEAE: Federated Learning Based Privacy-Preserving Event Ar...

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12th National CCF Conference on Natural Language Processing and Chinese Computing, NLPCC 2023

作者： Hu, Fei Dong, Shenpo Chang, Tao Zhou, Jie Li, Haili Wang, Jingnan Chen, Rui Liu, Haijiao Wang, Xiaodong National Key Laboratory of Parallel and Distributed Computing College of Computer Science and Technology National University of Defense Technology Changsha410073 China

ISBN: (纸本)9783031446955

Benefiting from Pre-trained Language Model (PLM), Event Argument Extraction (EAE) methods have achieved SOTA performance in general scenarios of Event Extraction (EE). However, with increasing concerns and regulations on data privacy, aggregating distributed data among different institutions in some privacy-sensitive territories (e.g., medical record analysis, financial statement analysis, etc.) becomes very difficult, and it’s hard to train an accurate EAE model with limited local data. Federated Learning (FL) provides promising methods for a large number of clients to collaboratively learn a shared global model without the need to exchange privacy-sensitive data. Therefore, we propose a privacy-preserving EAE method named FedEAE based on FL to solve the current difficulties. To better adapt to federated scenarios, we design a dataset named FedACE generated from the ACE2005 dataset under IID and Non-IID for our experiments. Extensive experiments show that FedEAE achieves promising performance compared to existing baselines, thus validates the effectiveness of our method. To the best of our knowledge, FedEAE is the first to apply FL in the EAE task. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

关键词： Extraction

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Development of a Wearable Upper Limb Rehabilitation Robot Based on Reinforced Soft Pneumatic Actuators

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 182-190页

作者： Xinbo Chen Shuai Zhang Kaibin Cao Chunjie Wei Wumian Zhao Jiantao Yao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China

Dyskinesia of the upper limbs caused by stroke,sports injury,or trafc accidents limits the ability to perform the activities of daily *** the necessary medical treatment,correct and scientifc rehabilitation training for the injured joint is an important auxiliary means during the treatment of the efected upper *** upperlimb rehabilitation robots have some disadvantages,such as a complex structure,poor compliance,high cost,and poor *** this study,a novel soft wearable upper limb rehabilitation robot(SWULRR)with reinforced soft pneumatic actuators(RSPAs)that can withstand high pressure and featuring excellent loading characteristics was *** by RSPAs,this portable SWULRR can perform rehabilitation training of the wrist and elbow *** this study,the kinematics of an SWULRR were analyzed,and the force and motion characteristics of RSPA were studied *** results provide a reference for the development and application of wearable upper limb rehabilitation *** experimental study on the rotation angle of the wrist and the pressure of the RSPA was conducted to test the efect of the rehabilitation training and verify the rationality of the theoretical *** process of wrist rehabilitation training was tested and evaluated,indicating that SWULRR with RSPAs will enhance the fexibility,comfort,and safety of rehabilitation *** work is expected to promote the development of wearable upper-limb rehabilitation robots based on modular reinforced soft pneumatic actuators.

关键词： Upper limb rehabilitation Reinforced soft pneumatic actuator Wearable rehabilitation robot Motion analysis

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