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Novel algorithm for complex bit reversal:employing vector permutation and branch reduction methods

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1492-1499页

作者： Feng yu Ze-ke WANG Rui-feng GE Department of lnstrument Engineering Zhejiang University Hangzhou 310027 China

We present novel vector permutation and branch reduction methods to minimize the number of execution cycles for bit reversal *** new methods are applied to single instruction multiple data(SIMD) parallel implementation of complex data floating-point fast Fourier transform(FFt).the number of operational clock cycles can be reduced by an average factor of 3.5 by using our vector permutation methods and by 1.1 by using our branch reduction methods,compared with conventional *** on MPC7448(a well-known SIMD reduced instruction set computing processor) demonstrate that our optimal bit-reversal algorithm consistently takes fewer than two cycles per element in complex array operations.

关键词： Bit reversal Vector permutation Branch reduction Single instruction multiple data (SIMD) Fast Fourier transform (FFt)

Evaluation of model checkers by verifying message passing programs

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Science China(Information Sciences) 2019年第10期62卷 6-30页

作者： Weijiang HONG Zhenbang CHEN Hengbiao yu Ji WANG College of Computer National University of Defense Technology State Key Laboratory of High Performance Computing National University of Defense Technology

Benchmarks and evaluation are important for the development of techniques and tools. Studies regarding evaluation of model checkers by large-scale benchmarks are few. the lack of such studies is mainly because of the language difference of existing model checkers and the requirement of intensive labor in building models. In this study, we present a large-scale benchmark for evaluating model checkers whose inputs are concurrent models. the benchmark consists of 2318 models that are generated automatically from real-world message passing interface(MPI) programs. the complexities of the models have been inspected to be well distributed and suitable for evaluating model checkers. Based on the benchmark, we have evaluated five state-of-the-art model checkers, i.e., PAt, FDR, Spin, PRISM, and NuSMV, by verifying the deadlock freedom property. the evaluation results demonstrate the ability and performance difference of these model checkers in verifying message passing programs.

关键词： model checker evaluation benchmark MPI symbolic execution

Construction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： Yong ZHAO tingyu ZHU Li yu Ming LU Sichuan–Xizang Railway Co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

the harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the ***,a comprehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to control the heat release of hot *** ventilation,ice chillers and other applicable measures are used to control the ambient ***,a monitoring and early warning system is established to prevent *** cooling strategy has been applied in the field with good results.

关键词： high geothermal tunnels cooling strategy comprehensive cooling measures safety and security

Ultra-sensitive detection of uranyl ions with a specially designed high-efficiency SERS-based microfluidic device

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Science China Chemistry 2019年第8期62卷 1064-1071页

作者： Xuan He Shaofei Wang yu Liu Xiaolin Wang College of Chemistry Sichuan UniversityChengdu 610064China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Institute of Materials China Academy of Engineering PhysicsMianyang 621907China China Academy of Engineering Physics Mianyang 621900China

the uranyl ion(UO22+) poses high risks to human health and the environment, hence its detection and monitoring is of utmost significance. However, the development of an ultra-sensitive, high-efficiency and convenient approach for on-site detection of UO22+ remains a challenge. Herein, a reliable and reusable surface-enhanced Raman spectroscopy(SERS)-based microfluidic biosensor was developed for rapid detection of UO22+ in real samples. the detection protocol involved the reaction of 5′-Rhodamine B(RhB)-labeled double-stranded DNA for UO22+-specific DNAzyme-cleavage reaction in a U-shaped microchannel. then, the reaction products were delivered into three parallel samples for high-throughput tests by SERS biochips,where 3 D ZnO-Ag mesoporous nanosheet arrays(MNSs) were modified with a single-stranded DNA(ssDNA). the ssDNAwas sequence-complementary with the 5′-RhB-labeled cleaved-stranded DNA(csDNA) from the reaction products. By the hybridization of ssDNA and csDNA, the signal probe RhB was fixed close to the surface of the ZnO-Ag MNSs to enhance the Raman signal. the limit of detection for UO22+ with the microfluidic-SERS biosensor was 3.71×10-15 M. An over 20,000-fold selectivity towards UO22+ response was also achieved in the presence of 15 other metal ions. the high-throughput microfluidicSERS biosensor operated well for practical UO22+ detection, with excellent recoveries in contaminated river and tap water from95.2% to 106.3%(relative standard deviation(RSD)though the SERS-based microfluidic biosensor developed in this study was deployed for the detection of UO22+, the reusable and high-efficiency system may be expanded to the detection of other analytes on-site.

关键词： uranyl ion DNAzyme SERS microfluidic device high-throughput reusable

CAtH: an effective method for detecting denial-of-service attacks in software defined networks

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Science China(Information Sciences) 2019年第3期62卷 75-89页

作者： Yi GUO Fu MIAO Liancheng ZHANG yu WANG State Key Laboratory of Mathematical Engineering and Advanced Computing Institute for Network Science and Cyberspace Tsinghua University School of Computer Science Henan University of Engineering

Software defined networks(SDNs) are innovative network frameworks that have recently received wide attention. their programming flexibility facilitates automatic network management and control, thus mitigating existing issues in the traditional network architecture. However, SDNs face several security risks,in particular denial-of-service(DoS) attacks, the most common and serious network attacks. to address such a threat, an SDN-DoS attack detection method is proposed based on fusing multiple flow features for describing the network catastrophe between the normal and the attack state. Several statistic attributes of SDN flow information are first chosen as detection features; subsequently, the cusp model is used to establish a catastrophe equilibrium surface for SDN states. After being trained, the cusp catastrophe model can be utilized to infer whether an SDN is under DoS attack. the experimental results demonstrate that the method can effectively and timely perceive SDN-DoS attacks, not only in simple networks but also in larger enterprise networks.

关键词： DoS attacks software defined network flow features cusp model equilibrium surface

A consistency improving method in the analytic hierarchy process based on directed circuit analysis

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Journal of Systems Engineering and Electronics 2019年第6期30卷 1160-1181页

作者： WU Shihui LIU Xiaodong LI Zhengxin ZHOU yu Equipment Management and UAV Engineering College Air force Engineering University

test of consistency is critical for the analytic hierarchy process(AHP) methodology. When a pairwise comparison matrix(PCM) fails the consistency test, the decision maker(DM) needs to make revisions. the state of the art focuses on changing a single entry or creating a new matrix based on the original inconsistent matrix so that the modified matrix can satisfy the consistency requirement. However, we have noticed that the reason that causes inconsistency is not only numerical inconsistency, but also logical inconsistency, which may play a more important role in the whole inconsistency. therefore, to realize satisfactory consistency, first of all, we should change some entries that form a directed circuit to make the matrix logically consistent, and then adjust other entries within acceptable deviations to make the matrix numerically consistent while preserving most of the original comparison information. In this paper, we firstly present some definitions and theories, based on which two effective methods are provided to identify directed circuits. Four optimization models are proposed to adjust the original inconsistent matrix. Finally, illustrative examples and comparison studies show the effectiveness and feasibility of our method.

关键词： analytic hierarchy process(AHP) pairwise compari son matrix(PCM) logical inconsistency numerical inconsistency directed circuit.

Instance selection method for improving graph-based semi-supervised learning

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Frontiers of Computer Science 2018年第4期12卷 725-735页

作者： Hai WANG Shao-Bo WANG yu-Feng LI 1 National Key Laboratory for Novel Software technology Nanjing University Nanjing 210023 China Collaborative Innovation Center of Novel Software technology and Industrialization Nanjing 210023 China

Graph-based semi-supervised learning is an important semi-supervised learning paradigm. Although graphbased semi-supervised learning methods have been shown to be helpful in various situations, they may adversely affect performance when using unlabeled data. In this paper, we propose a new graph-based semi-supervised learning method based on instance selection in order to reduce the chances of performance degeneration. Our basic idea is that given a set of unlabeled instances, it is not the best approach to exploit all the unlabeled instances; instead, we should exploit the unlabeled instances that are highly likely to help improve the performance, while not taking into account the ones with high risk. We develop both transductive and inductive variants of our method. Experiments on a broad range of data sets show that the chances of performance degeneration of our proposed method are much smaller than those of many state-of-the-art graph-based semi-supervised learning methods.

关键词： graph-based semi-supervised learning performance degeneration instance selection

Low CO content hydrogen production from oxidative steam reforming of ethanol over CuO-CeO_2 catalysts at low-temperature

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Journal of Energy Chemistry 2013年第6期22卷 861-868页

作者： Xue Han yunbo yu Hong He Jiaojiao Zhao Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at *** catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric *** CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 *** non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 *** results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.

关键词： CuO-CeO2 catalyst hydrogen production oxidative steam reforming low-temperature

Effect of back pressure on the grinding performance of abrasive suspension flow machining

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Advances in Manufacturing 2022年第1期10卷 143-157页

作者： Ming-Hui Fang tao yu Feng-Feng Xi Department of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444People’s Republic of China Shanghai University of Engineering Science Shanghai 201620People’s Republic of China Department of Aerospace Engineering Ryerson UniversityTorontoCanada

Abrasive suspension flow machining(ASFM)is an advanced finishing method that uses an abrasive suspension slurry for grinding and chamfering as well as the finishing of inaccessible *** study examines the effect of back pressure on the grinding characteristics of an abrasive suspension flow during the grinding of slender holes.A numerical model was developed to simulate the abrasive suspension flow in a slender hole and was verified experimentally using injector nozzle grinding equipment under different grinding pressures and back *** is shown that the ASFM with back pressure not only eliminates the cavitation flow in the spray hole,but also increases the number of effective abrasive particles and the flow *** the back pressure during the grinding process can increase the Reynolds number of the abrasive suspension flow and reduce the thickness of the boundary layer in the slender ***,increasing the back pressure can improve the flow rate of the injector nozzle and its grinding performance.

关键词： Abrasive suspension flow machining(ASFM)Back pressure Injector nozzle Grinding performance