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Global Classical Solutions to Partially Dissipative Quasilinear Hyperbolic Systems

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Chinese Annals of mathematics,Series B 2011年第5期32卷 771-780页

作者： Yi ZHOU 11 key laboratory of mathematics for Nonlinear Sciences,Ministry of Education,china Shanghai key laboratory for Contemporary applied mathematics School of Mathematical Sciences,Fudan University,Shanghai 200433,china. key laboratory of mathematics for Nonlinear Sciences Ministry of Education China Shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China

The author considers the Cauchy problem for quasilinear inhomogeneous hyperbolic *** the assumption that the system is weakly dissipative,Hanouzet and Natalini established the global existence of smooth solutions for small initial data (in *** ***.,Vol.169,2003,pp.89-117).The aim of this paper is to give a completely different proof of this result with slightly different assumptions.

关键词： Cauchy problem Global classical solution Partially dissipativequasilinear hyperbolic system

A class of binary cyclic codes with five weights

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Science china mathematics 2010年第12期53卷 3279-3286页

作者： LI ChunLei 1 , ZENG XiangYong 1, & HU Lei 2 1 Faculty of mathematics and Computer Science, hubei University, wuhan 43.062, china 2 The State key laboratory of Information Security, Graduate School of Chinese Academy of Sciences, Beijing 100049, china 1. Faculty of mathematics and Computer Science Hubei University Wuhan 430062 China2. The State Key Laboratory of Information Security Graduate School of Chinese Academy of Sciences Beijing 100049 China

In this paper, the dual code of the binary cyclic code of length 2 n-1 with three zeros α, α t 1 and α t 2 is proven to have five nonzero Hamming weights in the case that n 4 is even and t1 = 2 n/2 + 1, t2 = 2 n-1-2 n/2+1 + 1 or 2 n/2 + 3, where α is a primitive element of the finite field F 2 n . The dual code is a divisible code of level n/2+1, and its weight distribution is also completely determined. When n = 4, the dual code satisfies Ward's bound.

关键词： cyclic code Niho exponent exponential sum Pless power moment identity weight distribution

A class of additive-accelerated means regression models for recurrent event data

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Science china mathematics 2010年第12期53卷 3139-3151页

作者： LIU Li 1, MU XiaoYun 2 & SUN LiuQuan 2 1 School of mathematics and Statistics, wuhan University, wuhan 430072, china 2 Institute of applied mathematics, Academy of mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, china 1. School of mathematics and Statistics Wuhan University Wuhan 430072 China2. Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

In this article, we propose a class of additive-accelerated means regression models for analyzing recurrent event data. The class includes the proportional means model, the additive rates model, the accelerated failure time model, the accelerated rates model and the additive-accelerated rate model as special cases. The new model offers great flexibility in formulating the effects of covariates on the mean functions of counting processes while leaving the stochastic structure completely unspecified. For the inference on the model parameters, estimating equation approaches are derived and asymptotic properties of the proposed estimators are established. In addition, a technique is provided for model checking. The finite-sample behavior of the proposed methods is examined through Monte Carlo simulation studies, and an application to a bladder cancer study is illustrated.

关键词： additive-accelerated means model counting process marginal model model checking recurrent events

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 430072,china 2 State key laboratory of Software Engineering,wuhan University,wuhan 430072,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

Prediction of Tumor Outcome Based on Gene Expression Data

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wuhan University Journal of Natural Sciences 2004年第2期9卷 177-182页

作者： Liu Juan 1,2, Hitoshi Iba 3 1. School of Computer, wuhan University, wuhan 430072, hubei, china 2. State key laboratory of Software Engineering, wuhan 430072, hubei, china 3. Department of Frontier Informatics, University of Tokyo, Tokyo 113-8656, Japan wuhan University School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) State key laboratory of Software Engineering Wuhan Hubei China (GRID:grid.49470.3e) University of Tokyo Department of Frontier Informatics Tokyo Japan (GRID:grid.26999.3d) (ISNI:***)

Gene expression microarray data can be used to classify tumor types. We proposed a new procedure to classify human tumor samples based on microarray gene expressions by using a hybrid supervised learning method called MOEA+WV (Multi-Objective Evolutionary Algorithm+Weighted Voting). MOEA is used to search for a relatively few subsets of informative genes from the high-dimensional gene space, and WV is used as a classification tool. This new method has been applied to predicate the subtypes of lymphoma and outcomes of medulloblastoma. The results are relatively accurate and meaningful compared to those from other methods. key words bioinformatics - tumor classification - Pareto optimization - MOEA CLC number Q 786 - TP 181 Foundation item: Supported by the National Natural Science Foundation of china (60301009), the Foundation of Young Scholars of Ministry of Education of china (150118) and Chenguang Project of wuhan City (211121009).Biography: Liu Juan (1970-), female, Associate Professor, Postdoctoral, research direction: bioinformatics, data mining, machine learning.

关键词： bioinformatics tumor classification Pareto optimization MOEA

Endolithic fungi:A possible killer for the mass extinction of Cretaceous dinosaurs

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Science china Earth Sciences 2008年第6期51卷 801-807页

作者： GONG YiMing1,2, XU Ran1 & HU Bi2 1 key laboratory of Biogeology and Environmental Geology of Ministry of Education, State key laboratory of Geological Processes and Mineral Resources, china University of Geosciences, wuhan 430074, china 2 Institute of Resources and Environment key laboratory of Biogenic Traces & Sedimentary Minerals of Henan province, Henan Polytechnic University, Jiaozuo 454003, china 1. key laboratory of Biogeology and Environmental Geology of Ministry of Education State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 2. Institute of Resources and Environment key laboratory of Biogenic Traces & Sedimentary Minerals of Henan province Henan Polytechnic University Jiaozuo 454003 China

Mycelium-like structures found under ESEM within radial sections of fragmental dinosaur eggshells would be the endolithic fungi coexistent with dinosaur eggs in the upper part of the Late Cretaceous Hugang Formation from the Wenjiaping section of Wenxian, Danjiangkou, northwestern hubei, Central china. The endolithic fungi selectively occurred in the bad biomineral zone within the columnar layer of the eggshells, where the crowded endolithic fungi penetrated the columnar layer at near-vertical or near-horizontal angles. The endolithic fungi are needle-like, ribbon-like and silk-like, and 5–18 μm long, 0.3–0.5 μm wide at their base, with pointed tip, and are unbranched. The hyphae are mainly composed of oxygen, carbon and calcium, and are with minor sodium, potassium, chlorine and sulfur. The endolithic fungi and host have the same characters in lithification, fracture and main chemical composition. We suggested that the episode endolithic fungi invading dinosaur eggs may have taken place in the interval between after formation of dinosaur eggshells and before their petrification and that dinosaur eggs invaded by endolithic fungi would not be normally incubated or would only be incubated into venerable and pathologic baby dinosaurs to be easily to aborted and contributed to the mass extinction of the dinosaurs at the end of Cretaceous.

关键词： endolithic fungi dinosaur eggs mass extinction Cretaceous

Sharpness on the Lower Bound of the Lifespan of Solutions to Nonlinear Wave Equations

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Chinese Annals of mathematics,Series B 2011年第4期32卷 521-526页

作者： Yi ZHOU 1 Wei HAN 2 1 Nonlinear Mathematical Modeling and Methods laboratory Shanghai key laboratory for Contem- porary applied mathematics School of Mathematical Sciences, Fudan University, Shanghai 200433, china. 2 School of Mathematical Sciences, Fudan University, Shanghai 200433, china Department of mathematics, North University of china, Taiyuan 030051, china. Nonlinear Mathematical Modeling and Methods laboratory Shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China

This paper is devoted to proving the sharpness on the lower bound of the lifespan of classical solutions to general nonlinear wave equations with small initial data in the case n = 2 and cubic nonlinearity （see the results of T. T. Li and Y. M. Chen in 1992）. For this purpose, the authors consider the following Cauchy problem： { where □=δt^2-∑i=1n δx^^2 is the wave operator, g（x）（≡/） 0 is a smooth non-negative function with compact support, and ε 〉 0 is a small parameter. It is shown that the solution blows up in a finite time, and the lifespan T（ε） of solutions has an upper bound T（ε） ≤ exp（Aε-2） with a positive constant A independent of ε, which belongs to the same kind of the lower bound of the lifespan.

关键词： Nonlinear wave equation Cauchy problem Lifespan

Influence of TiO_2 Nano Particles on the Resistance to Corrosion and Mechanism of Cr_2O_3

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稀有金属材料与工程 2012年第S1期41卷 319-322页

作者： Cheng Xudong1,Peng Sheng1,Zhou Jiliang2,Zhu Zhenqi1 1 State key laboratory of Advanced Technology for Materials Synthesis and Processing,wuhan University of Technology,wuhan 430070,china 2 key laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission&Ministry of Education,hubei province,South-central University for Nationalities,wuhan 430074,china wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China State Ethn Affairs Commiss Key Lab Catalysis & Mat Sci Wuhan 430074 Hubei Province Peoples R China S Cent Univ Nationalities Minist Educ Wuhan 430074 Hubei Province Peoples R China

Cr2O3-based ceramic composite coatings with a NiCr intermediate layer adding nano TiO2 particles were synthesized by Air plasma spraying(APS)followed further seal *** coating samples were characterized by X-ray diffractions(XRD),scanning electron microscope(SEM).The corrosion behavior of coating was measured by weight loss in three solutions(HCl,NaOH,and NaCl).The relationships between the microstructure,corrosion behavior,and the content of TiO2 in coatings were *** the content of TiO2 was relative high,the coating was composed of(Cr0.88Ti0.12)2O3 and Cr2O3 *** sealing,the coating weight decreased all long in three kinds of ***,after sealing treatment the coating weight decreased early but increased later,changed periodically as *** curve and electrochemical impedance spectroscopy(EIS) were performed to study the corrosion *** results showed that like organic coating,the corrosion of ceramic coating included three stages,in which the weight of samples decreased or increased corresponding to different physical and physical or chemical *** salt spray test showed the Cr2O3-based ceramic composite coating had an excellent decay resistance in marine environment.

关键词： corrosion resistance ceramic coating air plasma spray

An eSnake model for medical image segmentation

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Progress in Natural Science:Materials International 2005年第5期15卷 424-429页

作者： Lv Hongyu1, YUAN Kehong2, BAO Shanglian1, ZU Donglin1 and DUAN Chaijie1*(1. The Research Center for Tumor Diagnosis and Therapeutical Physics & Beijing key laboratory of Medical Physics and Engineering, Beijing 100871, china 2. key laboratory of Pure and applied mathematics, School of Mathematical Sciences, Peking University, Beijing 100871, china) The Research Center for Tumor Diagnosis and Therapeutical Physics & Beijing key laboratory of Medical Physics and Engineering Beijing 100871 China key laboratory of Pure and applied mathematics School of Mathematical Sciences Peking University Beijing 100871 China

A novel scheme of external force for detecting the object boundary of medical image based on Snakes (active contours) is introduced in the paper. In our new method, an electrostatic field on a template plane above the original image plane is designed to form the map of the external force. Compared with the method of Gradient Vector Flow (GVF), our approach has clear physical meanings. It has stronger ability to conform to boundary concavities, is simple to implement, and reliable for shape segmenting. Additionally, our method has larger capture range for the external force and is useful for medical image preprocessing in various applications. Finally, by adding the balloon force to the electrostatic field model, our Snake is able to represent long tube-like shapes or shapes with significant protrusions or bifurcations, and it has the specialty to prevent Snake leaking from large gaps on image edge by using a two-stage segmentation technique introduced in this paper. The test of our models proves that our methods are robust, precise in medical image segmentation.

关键词： image segmentation eSnake external force electrostatic field balloon force.