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An efficient method for detecting concurrency errors in object-oriented programs

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Science china(Information Sciences) 2012年第12期55卷 2774-2784页

作者： HE YanXiang 1,2,WU Wei 2 & CHEN Yong 2 1 school of Computers,wuhan university,wuhan 43.072,china 2 State Key Laboratory of Software Engineering,wuhan university,wuhan 43.072,china 1. school of Computers Wuhan University Wuhan 430072 China2. State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 China

Multicore and multi-threaded processors have become the norm for modern ***,concurrent programs have become more and more prevalent despite being difficult to write and *** errors are highly likely to appear in concurrent code,conventional error detection methods such as model checking,theorem proving,and code analysis do not scale smoothly to concurrent *** is an indispensable technique for detecting concurrency errors,but it involves a great deal of manual work and is *** paper presents an automatic method for detecting concurrency errors in classes in object-oriented *** method uses a heuristic algorithm to automatically generate test cases that can effectively trigger ***,each test case is executed automatically and a fast method is adopted to identify the actual concurrency error from anomalous run *** have implemented a prototype of the method and applied it to some typical Java *** shows that our method is more effective and faster than previous work.

关键词： concurrency error dynamic test data race atomicity violations test case generation

Numerical study of the auroral particle transport in the polar upper atmosphere

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Science china(Technological Sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3.1 school of Electronic Information, wuhan university, wuhan 43.079,{3. 2 Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, wuhan 43.079,{3. 3.school of Earth and Space Sciences, Peking university, Beijing 100871,{3. 1. school of Electronic Information Wuhan University Wuhan 430079 China 2. Key Laboratory of Geospace Environment and Geodesy Ministry of Education of PRC Wuhan 430079 China 3. school of Earth and Space Sciences Peking University Beijing 100871 China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

Microwave Sintering of W-15Cu Ultrafine Composite Powder Prepared by Spray Drying & Calcining-continuous Reduction technology

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Journal of wuhan university of technology(Materials Science) 2011年第2期26卷 281-284页

作者：舒敬萍 Engineering Training Center Wuhan University of Technology

The effects of microwave sintering and conventional H2 sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying ＆ calcining-continuous reduction technology were investigated. In comparison to the conventional HE sintering processing, microwave sintering to W-15Cu can be achieved at lower sintering temperature and shorter sintering time. Furthermore, higher performances in microwave sintered compacts were obtained, but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.

关键词： W-15Cu ultrafine composite powder spray drying & calcining continuous reduction microwave sintering

Electronic Structure of Doped Trans-Polyacetylene

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wuhan university Journal of Natural Sciences 2002年第1期7卷 51-53页

作者： Ren Da-zhi 1,2, Zhuang Wei 2, Wang Jun 2 1. wuhan university Journals Press,wuhan 43.072,Hubei,{3. 2. school of Physics and technology, wuhan university, wuhan 43.072,Hubei,{3. wuhan university Journals Press Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The behavior of electronic structures of doped trans-polyacetylene is revealed by a simple method. (C24H26)+n is used to simulate p-type doped trans-polyacetylene at various doping concentrations. The electronic structure is calculated, by CNDO/2 method. These calculations show that at low doping level, the decrease of electronic energy compensates the increase of elastic energy, thus the bond alternation exists, and the charge carriers are solitons. When doping level is high, the increase of elastic energy is larger than the decrease, of electronic energy, the bond alternation disappears, solitons no longer exist, and polyacetylene is in a metalic state.

关键词： trans polyacetylene CNDO/2 electronic structure doped

A RAISED PANEL METHOD BASED ON NURBS FOR FREE-SURFACE POTENTIAL FLOWS WITH FORWARD SPEED

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Journal of Hydrodynamics 2003年第2期15卷 112-120页

作者： Gao Gao, Ma Lingschool of Transportion, wuhan university of technology, {3. 43.063. china school of Transportion Wuhan University of Technology Wuhan 430063 China

A raised panel method based on NURBS (Non-Uniform Rational B-Splines) forfree-surface flows with forward speed is presented. In this generalized panel method, NURBS areemployed to represent the body geometry, disturbed free surface, and to express the unknown sourcestrength distribution, on the body surface and above the free surface. Compared with commonhigher-order panel methods, it has no need of adopting local coordinates. NURBS make the geometryrepresentation of the body shape and the wave pattern more precise. Raised panels above the freesurface produce less numerical dispersion error, need less CPU consumption and are helpful andcombined with collocation-point shifting up-stream, can satisfy the radiation condition *** using continuous and discrete Fourier analysis, numerical errors of this method are discussedand a general expression for the errors of numerical damping and dispersion, including the effectsof the vertical distance of singularities to the free surface, the order of singularity distributionrepresented by B-splines in panels, and collocation-point shifting is derived.

关键词： NURBS free-surface flow raised panel method error analysis B-spline

NUMERICAL INVESTIGATIONS INTO THE FRICTION REDUCTION BY MICROBUBBLES FOR FLAT PLATES

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Journal of Hydrodynamics 2003年第3期15卷 82-88页

作者： Zhan De-xin, Wang Jia-mei, Lin Li-ming school of Transportation, wuhan university of technology, {3. 43.063. china, schoolofTransportation WuhanUniversityofTechnologyWuhan430063China

The two-dimensional flow on the flat plate with injected microbubbles issimulated using the software, PHOENICS (V3. 2), usually used in the CFD (Computational FluidDynamics). A set of formulas for K-ε turbulence model modified with the presence of microbubbles,is employed. With considering the effect of gravity, interfacial lift, inter-phase friction, virtualmass force and interfacial pressure on the flow with microbubbles, numerical calculations for theinfluence of variable air volume fracton as well as distribution, injecting speed, microbubblediameter and position of introducing microbubbles on the friction reduction are presented. Resultsshow that the friction reduction increases with increasing volume fraction and microbubble diameterwithin the range of 100μm, and that the velocity in the boundary layer with microbubbles is greaterthan that without microbubbles. The order of magnitude and trends of the experimental skin-frictionare reproduced well. The uniform free-stream speed in all cases is 4m/s, giving Reynolds number ofup to 20 million.

关键词： flat plate friction reduction by microbubbles modified K-ε turbulencemodel numerical simulation

An architecture for mobile database management system

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Journal of university of Science and technology Beijing 2002年第2期9卷 156-160页

作者： Dong Li and Yucai Feng Computer school, Huazhong university of Science and technology, {3. 43.074, china Computer school Huazhong University of Science and Technology Wuhan 430074 China

In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introduced that the mobile database is a kind of dynamicdistributed database, and the concept of virtual servers to translate the clients' mobility to theservers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, whichis of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.

关键词： mobile database dynamic distributed database DBMS architecture virtual server data region

Preparation and Characterization of Polylactide/Montmorillonite Nanocomposites

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Journal of wuhan university of technology(Materials Science) 2009年第4期24卷 562-565页

作者：吴选军 school of Chemical Engineering Wuhan University of Technology

The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount（5wt%） of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%（pure PLA film） to 3.2.65%. The results of wide-angle X-ray diffraction （WAXD） patterns confirmed that the silicate interlayer distance increased from 3.044 nm （for OMMT） to 3.56nm （for 5wt%, maximum） with increasing OMMT contents, but decreased to 3.3.9 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.

关键词： polylactide montmorillonite nanocomposite characterization thermo-mechanic at property

Early Age Compressive Strength of Pastes by Electrical Resistivity Method and Maturity Method

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Journal of wuhan university of technology(Materials Science) 2011年第5期26卷 983-989页

作者：肖莲珍 school of Materials Science and Engineering Wuhan Institute of Technology

The compressive strength development of Portland cement pastes was investigated by the electrical resistivity method and the maturity *** experiments were carried out on the cement pastes with different water-cement ratios at different curing *** results show that the application of the maturity method has limitation to obtain the *** is found that both of the compressive strength and the electrical resistivity follow hyperbolic trend for all the *** hyperbolic equation of each mix is obtained to estimate the ultimate resistivity value which can probably be *** relationship between electrical resistivity and compressive strength of the cement pastes is established based on the test results and interpreted by the empirical Archie equation and a strength-porosity *** relationship between the electrical resistivity after temperature correction and the compressive strength was linear and independent of curing temperature and water-cement ratio.

关键词： electrical resistivity cement hydration compressive strength maturity method