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Scratchpad memory allocation for arrays in permutation graphs

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Science China(Information Sciences) 2013年第5期56卷 251-263页

作者： WANG Li yang xuejun DAI HuaDong School of Computer National University of Defense Technology

In modern embedded systems,on-chip memory is generally organized as software-managed scratchpad memory(SPM).Li et *** that in many embedded applications,the array interference graphs tend to be superperfect *** on this,they presented a superperfect graph-based SPM allocation algorithm,which is the best in the *** this paper,we make further progress in proving that the array interference graphs they focused on are permutation graphs;that is,a subclass of a superperfect *** to the latter,the permutation graph has certain advantages,such as linear time recognition and linear time optimal interval *** on our theoretical results,we improve their algorithm by transforming it into a permutation graph-based one by means of simple plug-in *** experiments confirm that the improved algorithm achieves optimal coloring,and therefore,better allocation than the original superperfect graph-based algorithm for a broader scope of array interference graphs.

关键词： scratchpad memory SPM allocation interval coloring superperfect graph permutation graph

Acyclic orientation graph coloring for software-managed memory allocation

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Science China(Information Sciences) 2014年第9期57卷 40-57页

作者： WANG Li XUE JingLing yang xuejun School of Computer National University of Defense Technology School of Computer Science and Engineering University of New South Wales

This paper presents a novel compiler algorithm,called acyclic orientation graph coloring(AOG coloring),for managing data objects in software-managed memory *** key insight is that softwaremanaged memory allocation could be solved as an interval coloring problem,or equivalently,an acyclic orientation *** generalize graph coloring register allocation to interval coloring memory allocation by maintaining an acyclic orientation to the currently colored *** is achieved with some well-crafted heuristics,including Aggressive Simplify that does not necessarily preserve colorability and Best-Fit Select that assigns intervals(i.e.,colors)to nodes by possibly adjusting the colors already assigned to other nodes *** algorithm generalizes and subsumes as a special case the classical graph coloring register allocation algorithm without notably increased complexity:it deals with memory allocation while preserving the elegance and practicality of traditional graph coloring register *** have implemented our algorithm and tested it on Appel’s 27921 interference graphs for scalars(augmented with node weights).Our algorithm outperforms Memory Coloring,the best in the literature,for software-managed memory allocation,on 98.64%graphs,in which,the gaps are more than 20%on 68.31%graphs and worse only on 0.29%*** also tested it on all the 73 DIMACS weighted benchmarks(weighted graphs),AOG Coloring outperforms Memory Coloring on all of the benchmarks,in which,the gaps are more than 20%on 83.56%graphs.

关键词： graph coloring memory coloring interval coloring acyclic orientation software-managed memory

Optimal subsystem approach to multi-qubit quantum state discrimination and experimental investigation

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Science China(Physics,Mechanics & Astronomy) 2018年第2期61卷 26-34页

作者： ShiChuan Xue JunJie Wu Ping Xu xuejun yang State Key Laboratory of High Performance Computing National University of Defense Technology College of Computer National University of Defense Technology

Quantum computing is a significant computing capability which is superior to classical computing because of its superposition feature. Distinguishing several quantum states from quantum algorithm outputs is often a vital computational task. In most cases, the quantum states tend to be non-orthogonal due to superposition; quantum mechanics has proved that perfect outcomes could not be achieved by measurements, forcing repetitive measurement. Hence, it is important to determine the optimum measuring method which requires fewer repetitions and a lower error rate. However, extending current measurement approaches mainly aiming at quantum cryptography to multi-qubit situations for quantum computing confronts challenges, such as conducting global operations which has considerable costs in the experimental realm. Therefore, in this study, we have proposed an optimum subsystem method to avoid these difficulties. We have provided an analysis of the comparison between the reduced subsystem method and the global minimum error method for two-qubit problems; the conclusions have been verified experimentally. The results showed that the subsystem method could effectively discriminate non-orthogonal two-qubit states, such as separable states, entangled pure states, and mixed states; the cost of the experimental process had been significantly reduced, in most circumstances, with acceptable error rate. We believe the optimal subsystem method is the most valuable and promising approach for multi-qubit quantum computing applications.

关键词： quantum computing quantum measurement quantum state discrimination entanglement reduced density operators

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Protocol-Aware Process Placement for MPI Programs

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Chinese Journal of Electronics 2014年第4期23卷 701-705页

作者： XU Xinhai LIN Yufei yang xuejun State Key Laboratory of High Performance Computing National University of Defense Technology

Current parallel programs are often composed of lots of processes that communicate through message passing. The mapping of the program processes onto the underlying processor. By analyzing the MPI library,we find that the communication protocols have great influence upon the communication characteristics. The profiling information used by the existing process placement methods does not include the communication protocols. We propose and implement a method called Protocol-aware process placement(Pa PP) to incorporate the influences of communication protocols into the mapping problem. We demonstrate the validations of Pa PP by the experiments using NPB3.3-MPI benchmarks. The experimental results show that compared to basic process placement, the average execution time when using Pa PP scheme is reduced by 9.5%.

关键词： Process placement Communication protocol Graph mapping MPI

CNN Feature Boosted SeqSLAM for Real-Time Loop Closure Detection

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Chinese Journal of Electronics 2018年第3期27卷 488-499页

作者： BAI Dongdong WANG Chaoqun ZHANG Bo YI Xiaodong yang xuejun College of Computer National University of Defense Technology State Key Laboratory of High Performance Computing National University of Defense Technology National Institute of Defense Technology Innovation

This paper proposes an efficient and robust Loop closure detection(LCD) method based on Convolutional neural network(CNN) feature. The primary method is called SeqCNNSLAM, in which both the outputs of the intermediate layer of a pre-trained CNN and the outputs of traditional sequence-based matching procedure are incorporated, making it possible to handle the viewpoint and condition variance properly. An acceleration algorithm for SeqCNNSLAM is developed to reduce the search range for the current image, resulting in a new LCD method called A-SeqCNNSLAM. To improve the applicability of A-SeqCNNSLAM to new environments, O-SeqCNNSLAM is proposed for online parameters adjustment in A-SeqCNNSLAM. In addition to the above work, we further put forward a promising idea to enhance Seq SLAM by integrating the both CNN features and VLAD’s advantages called patch based Seq CNNSLAM(P-SeqCNNSLAM), and provide some preliminary experimental results to reveal its performance.

关键词： Simultaneous localization and mapping(SLAM) Loop closure detection(LCD) Convolutional neural network(CNN) SeqSLAM SeqCNNSLAM A-SeqCNNSLAM O-SeqCNNSLAM P-SeqCNNSLAM

A Bayesian validation approach to practical boson sampling

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Science China(Physics,Mechanics & Astronomy) 2020年第5期63卷 39-46页

作者： Zhe Dai Yong Liu Ping Xu WeiXia Xu xuejun yang JunJie Wu Institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer National University of Defense TechnologyChangsha 410073China

Boson sampling is a promising candidate for demonstrating quantum supremacy. The validation that involves judging whether a quantum setup outputs photons following the boson sampling model is an essential task in the experiments. However, the current validation methods may result in an incorrect conclusion being reached in realistic experiments, in which no ideally identical photons exist. Accordingly, this study proposes a slope-based approach, which is an extended Bayesian validation, to model the degree of photon indistinguishability. Through numerical simulations and performance evaluations, we demonstrate that the proposed approach can correctly validate boson sampling against the distribution of classical particles. In addition to offering a useful approach for validation, our research indicates that physicists should pay more attention to the quality of photon indistinguishability in boson sampling experiments.

关键词： boson sampling quantum supremacy Bayesian validation photon indistinguishability

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A benchmark test of boson sampling on Tianhe-2 supercomputer

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National Science Review 2018年第5期5卷 715-720页

作者： Junjie Wu Yong Liu Baida Zhang Xianmin Jin yang Wang Huiquan Wang xuejun yang Institute for Quantum Information & State Key Laboratory of High Performance Computing College of ComputerNational University of Defense Technology State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong University Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China

Boson sampling, thought to be intractable classically, can be solved by a quantum machine composed of merely generation, linear evolution and detection of single photons. Such an analog quantum computer for this specific problem provides a shortcut to boost the absolute computing power of quantum computers to beat classical ones. However, the capacity bound of classical computers for simulating boson sampling has not yet been identified. Here we simulate boson sampling on the Tianhe-2 supercomputer, which occupied the first place in the world ranking six times from 2013 to 2016. We computed the permanent of the largest matrix using up to 312 000 CPU cores of Tianhe-2, and inferred from the current most efficient permanent-computing algorithms that an upper bound on the performance of Tianhe-2 is one 50-photon sample per ～100 min. In addition, we found a precision issue with one of two permanent-computing algorithms.

关键词： boson sampling permanent quantum supremacy quantum computing supercomputer

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导电水凝胶在脊髓损伤修复中应用的研究进展

中华创伤杂志 2024年第7期40卷 647-653页

作者：黄智刘胜祥王瀚博达逸峰邢文华杨学军李峰内蒙古医科大学第二附属医院脊柱外科中心A区呼和浩特010000

脊髓损伤是一种严重的中枢神经系统损伤,具有较高的致残率和病死率,严重影响患者的生活质量。目前各种脊髓损伤的治疗方法,如手术、药物和康复等难以实现脊髓的修复、神经功能的改善。电刺激可加速轴突生长和髓鞘形成,促进神经组织修复... 详细信息

脊髓损伤是一种严重的中枢神经系统损伤,具有较高的致残率和病死率,严重影响患者的生活质量。目前各种脊髓损伤的治疗方法,如手术、药物和康复等难以实现脊髓的修复、神经功能的改善。电刺激可加速轴突生长和髓鞘形成,促进神经组织修复和再生。可负载电刺激的导电水凝胶在脊髓损伤的治疗中具有较大潜力。在电刺激作用下,不同类型的导电水凝胶各具特性,可发挥多种功能,但临床医师对其在脊髓损伤修复中的应用效果尚缺乏全面认识。为此,笔者就电刺激在脊髓损伤修复中的作用和不同类型导电水凝胶的特性及其在脊髓损伤修复中应用的研究进展进行综述,为用于脊髓损伤修复的导电水凝胶的合成与临床转化提供参考。

关键词：水凝胶脊髓损伤电刺激

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Tri-Co Robot: a Chinese robotic research initiative for enhanced robot interaction capabilities

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National Science Review 2018年第6期5卷 799-801页

作者： Han Ding xuejun yang Nanning Zheng Ming Li Yinan Lai Hao Wu State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Institute of Artificial Intelligence and Robotics Xi’an Jiaotong University National Natural Science Foundation of China

Since the invention of the first industrial robot in 1959, the missions of robots have evolved from basic mechanical transfer or assistance to a diverse range of tasks through close interactions with environment, their human counterparts and robot peers. Through adaptation to uncertain and dynamic environments, legged robots can achieve coordinated locomotion in rough terrain, even

关键词： Co a Chinese robotic research initiative for enhanced robot interaction capabilities Tri-Co Robot