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Learning a graph-based classifier for fault localization

Science China(Information Sciences) 2020年第6期63卷 195-216页

作者： Hao zhong Hong MEI department of Computer Science and Engineering Shanghai Jiao Tong University

Because software emerged, locating software faults has been intensively researched, culminating in various approaches and tools that have been applied in real development. despite the success of these developments, improved tools are still demanded by programmers. Meanwhile, some programmers are reluctant to use any tools when locating faults in their development. The state-of-the-art situation can be naturally improved by learning how programmers locate faults. The rapid development of open-source software has accumulated many bug fixes. A bug fix is a specific type of comments containing a set of buggy files and their corresponding fixed files, which reveal how programmers repair bugs. Feasibly, an automatic model can learn fault locations from bug fixes, but prior attempts to achieve this vision have been prevented by various technical challenges. For example, most bug fixes are not compilable after checking out, which hinders analyzing bug fixes by most advanced static/dynamic tools. This paper proposes an approach called ClaFa that trains a graph-based fault classifier from bug fixes. ClaFa is built on a recent partial-code tool called Grapa, which enables the analysis of partial programs by the complete code tool called WALA. Once Grapa has built a program dependency graph from a bug fix, ClaFa compares the graph from the buggy code with the graph from the fixed code, locates the buggy nodes, and extracts the various graph features of the buggy and clean nodes. Based on the extraction result, ClaFa trains a classifier that combines Adaboost and decision tree learning. The trained ClaFa can predict whether a node of a program dependency graph is buggy or *** evaluate ClaFa on thousands of buggy files collected from four open-source projects: Aries, Mahout,derby, and Cassandra. The f-scores of ClaFa achieves are approximately 80% on all projects.

关键词： fault classifier partial code analysis bug fix analysis

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A low-to-high friction transition in gradient nano-grained Cu and Cu–Ag alloys

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Friction 2021年第6期9卷 1558-1567页

作者： Xiang CHEN zhong HAN Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China

A unique low-to-high friction transition is observed during unlubricated sliding in metals with a gradient nano-grained(GNG)surface *** persisting in the low-friction state(0.2–0.4)for tens of thousands of cycles,the coefficients of friction in the GNG copper(Cu)and copper-silver(Cu–5Ag)alloy start to increase,eventually reaching a high level(0.6–0.8).By monitoring the worn surface morphology evolution,wear-induced damage accumulation,and worn subsurface structure evolution during sliding,we found that the low-to-high friction transition is strongly correlated with distinct microstructural instabilities induced by vertical plastic deformation and wear-off of the stable nanograins in the subsurface layer.A very low wear loss of the GNG samples was achieved compared with the coarse-grained sample,especially during the low friction *** results suggest that it is possible to postpone the initiation of low-to-high friction transitions and enhance the wear resistance in GNG metals by increasing the GNG structural stability against grain coarsening under high loading.

关键词： gradient nano-grained metals Cu and Cu–Ag alloy low-to-high friction transition subsurface plastic deformation wear

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Predication of topological states in the allotropes of group-IV elements

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Frontiers of physics 2021年第6期16卷 117-124页

作者： Chengyong zhong National Laboratory of Solid State Microstructures and department of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China Institute for Advanced Study Chengdu UniversityChengdu 610106China

Three-dimensional(3d)topological insulators(TIs)have been studied for approximately fifteen years,but those made from group-IV elements,especially Ge and Sn,seem particularly attractive owing to their nontoxicity,sizable intrinsic spin–orbit coupling(SOC)strength and natural compatibility with the current semiconductor ***,group-IV elemental TIs have rarely been reported,except for the low temperature phase ofα-Sn under ***,based on first-principles calculations,we propose new allotropes of Ge and Sn,named T5-Ge/Sn,as desirable *** new allotropes are also highly anisotropic dirac semimetals if the SOC is turned *** the best of our knowledge,T5-Ge/Sn are the first 3d allotropes of Ge/Sn that possess topological states in their equilibrium states at room ***,their isostructures of C and Si are metastable indirect and direct *** work not only reveals two promising TIs,but more profoundly,we justify the advantages of group-IV elements as topological quantum materials(TQMs)for fundamental research and potential practical applications,and thus reveal a new direction in the search for desirable TQMs.

关键词： topological insulators topological semimetals group-IV elements first-principles calculations

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Cardiovascular computed tomography in cardiovascular disease:An overview of its applications from diagnosis to prediction

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Journal of Geriatric Cardiology 2024年第5期21卷 550-576页

作者： zhong-Hua SUN discipline of Medical Radiation Science Curtin Medical SchoolCurtin UniversityPerthAustralia Curtin Health Innovation Research Institute(CHIRI) Curtin UniversityPerth 6012Australia

Cardiovascular computed tomography angiography(CTA)is a widely used imaging modality in the diagnosis of cardiovascular *** in CT imaging technology have further advanced its applications from high diagnostic value to minimising radiation exposure to *** addition to the standard application of assessing vascular lumen changes,CTA-derived applications including 3d printed personalised models,3d visualisations such as virtual endoscopy,virtual reality,augmented reality and mixed reality,as well as CT-derived hemodynamic flow analysis and fractional flow reserve(FFRCT)greatly enhance the diagnostic performance of CTA in cardiovascular *** widespread application of artificial intelligence in medicine also significantly contributes to the clinical value of CTA in cardiovascular *** value of CTA has extended from the initial diagnosis to identification of vulnerable lesions,and prediction of disease extent,hence improving patient care and *** this review article,as an active researcher in cardiovascular imaging for more than 20 years,I will provide an overview of cardiovascular CTA in cardiovascular *** is expected that this review will provide readers with an update of CTA applications,from the initial lumen assessment to recent developments utilising latest novel imaging and visualisation *** will serve as a useful resource for researchers and clinicians to judiciously use the cardiovascular CT in clinical practice.

关键词： diagnosis cardiovascular prediction

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A Result on Fractional(a,b,k)-critical Covered Graphs

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Acta Mathematicae Applicatae Sinica 2021年第4期37卷 657-664页

作者： Si-zhong ZHOU School of Science Jiangsu University of Science and TechnologyZhenjiang212100China

A fractional[a,b]-factor of a graph G is a function h from E(G)to[0,1]satisfying a≤d^(h)_(G)(v)≤b for every vertex v of G,where d^(h)_(G)(v)=∑e∈E(v)h(e)and E(v)={e=uv:u∈V(G)}.A graph G is called fractional[a,b]-covered if G contains a fractional[a,b]-factor h with h(e)=1 for any edge e of G.A graph G is called fractional(a,b,k)-critical covered if G—Q is fractional[a,b]-covered for any Q⊆V(G)with∣Q∣=*** this article,we demonstrate a neighborhood condition for a graph to be fractional(a,b,k)-critical ***,we claim that the result is sharp.

关键词： graph neighborhood fractional[a,6]-factor fractional[a.6]-covered graph fractional(a.b,k)-critical covered graph

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EXPLICIT SIMULATION ON THE TRACK ANd INTENSITY OF TROPICAL CYCLONE WINNIE (1997)

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Journal of Hydrodynamics 2006年第6期18卷 736-741页

作者： zhong zhong ZHANG Jirl-shan Institute of Meteorology PLA University of Science and Technology Nanjing 211101 China Nanjing Hydraulic Research Institute Nanjing 210029 China

An explicit simulation of the tropical cyclone Winnie （1997） was conducted by use of a triply-nested 3-d nonhydrostatic mesoscale model MM5, before and after its landfall. The simulated results show that the model can well reproduce the track of Winnie （1997） with a BOGUS storm-like vortex inserted in the large-scale first-guess field at the initial model time. The mean track error in a 6 h interval is 54.5 km, which is much less than that obtained with the operational prediction. Comparisons between simulation and observation near the landfall place show that the main temporal variation features of sea level pressure and surface wind speed can also be successfully captured. The characteristics of the eyewall, the spiral cloud band and the corresponding precipitation were disclosed, and the applications of the model outputs were also discussed.

关键词： tropical cyclone simulation track intensity,eyewall spiral cloud band storm surge

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Equilibrium Piezoelectric Potential distribution in a deformed ZnO Nanowire

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Nano Research 2009年第8期2卷 624-629页

作者： Giulia Mantini Yifan Gao A.dʼAmico C.Falconi zhong Lin Wang School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGeorgia 30332-0245USA department of Electronic Engineering University of Tor VergataVia del Politecnico 100133 RomaItaly

The equilibrium piezoelectric potential distribution in a deformed ZnO semiconductive nanowire has been systematically investigated in order to reveal its dependence on the donor concentration,applied force,and geometric *** particular,the donor concentration markedly affects the magnitude and distribution of the electric *** a donor concentration of Nd>1018 cm-3,the piezopotential is almost entirely *** the other parameters,a variation in the length of the nanowire does not signifi cantly affect the potential distribution.

关键词： Nanogenerator ZnO nanowire

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Novel backstepping design for blended aero and reaction-jet missile autopilot

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Journal of Systems Engineering and Electronics 2008年第1期19卷 148-153页

作者： Liu zhong Jia Xiaohong Opto-Electro Technology development Center Luoyang 471009 P.R. China

The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model uncertain, is much more complex than conventional nero-fin control. A novel nonlinear backstepping control approach is proposed to design the blended autopilot. Missile model is reformed to a new one by state reconstruction technique so that it is easy to be handled by the backstepping method. Then a Lyapunov function is chosen to avoid oscillation caused in normal backstepping way when control parameters are mismatched. In distribution of both inputs, optimal energy logic is proposed. In addition, a fuzzy cerebellar model articulation controller （FCMAC） neural network is used to guarantee controller robustness to uncertainties. Finally, simulation results demonstrate the efficiency and advantages of the proposed method.

关键词： missile control blended aero-fin and reaction-jet control nonlinear backstepping optimal enery logic.

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Numerical study of the dynamic characteristics of a single-layer graphite core in a thorium molten salt reactor

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Nuclear Science and Techniques 2018年第10期29卷 171-181页

作者： Yang zhong Xiong Yang dong ding Yang Zou d.K.L.Tsang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A reactor core in a thorium molten salt reactor uses graphite as a moderator and reflector. The graphite core is a multi-layered arrangement of graphite bricks that are loosely connected to each other using a system of keys and dowels. Consequently, the graphite core is a type of discrete stack structure with highly nonlinear dynamic behavior. Hence, it is important to investigate the dynamic characteristics of the graphite core. In this study, a threedimensional single-layer graphite core model, which is a part of the thorium molten salt reactor side reflector structure, was analyzed using the explicit method in ABAQUS 2016 to study the core dynamic behavior when subjected to different excitations. The design parameters,such as the diameter of the dowel, the gap between key and keyway and the bypass flow gap between two adjacent bricks, were also considered in this model. To reduce excessive demands on available computational resources considering the effect of molten salt, the spring–dashpot model was applied to model the interaction forces between the molten salt and graphite bricks. Numerical simulation results show that the effect of molten salt is a reduction inthe peak maximal principal stress, and a larger gap between two bricks is beneficial to maintain the integrity of the graphite core under earthquake loading. The results obtained by the simulation can be used as a reference for future designs of a molten salt graphite core.

关键词： Graphite core dynamic behavior ABAQUS

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Image-Based 3d Pose Reconstruction of Surgical Needle for Robot-Assisted Laparoscopic Suturing

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Chinese Journal of Electronics 2018年第3期27卷 476-482页

作者： zhong Fangxun LIU Yunhui CUHK T Stone Robotics Institute The Chinese University of Hong Kong

We present a new method to solve the recognition and localisation problem of a surgical needle for robot-assisted laparoscopy. Based on the observation from a single monocular laparoscopic image, we propose a new modelling method to parametrise the full 3 d pose of the surgical needle by constrained degrees of freedom(dOFs) using only two generalised variables. To obtain effective image feedback for the modelling, a feature segmentation algorithm is introduced from probabilistic linear constraints in RGB colour space, constructed from typical laparoscopic images. An iterative algorithm using gradient descent rule is implemented to converge the computed needle's pose to its real one. Experiments demonstrate the feasibility of the proposed scheme using laparoscopic torso models.

关键词： Suturing needle Pose reconstruction Robot-assisted laparoscopy Image segmentation

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