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A new DNA algorithm to solve graph coloring problem

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Progress in Natural science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3 and Meng Dazhi2(1. National Laboratory of Pattern Recognition,institute of Automation, Chinese Academy of sciences, beijing 100080, china 2. College of Applied sciences, beijing University of technology, beijing 100022, china 3. school of science, beijing institute of technology, beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China National High Magnetic Field Laboratory Florida State University 1800 East Paul Dirac Drive Tallahassee Florida 32306 USA

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

Research on resolution between multi-component LFM signals in the fractional Fourier domain

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science china(Information sciences) 2012年第6期55卷 1301-1312页

作者： LIU Feng 1,XU HuiFa 1,2,TAO Ran 3 & WANG Yue 3 1 Department of Electronic and Information Engineering,Naval Aeronautical Engineering institute,Yantai 264001,china 2 The 94362 th Unit of People's Liberation Army,Qingdao 266111,china 3 school of Information science and technology,beijing institute of technology,beijing 100081,china Department of Electronic and Information Engineering Naval Aeronautical Engineering Institute Yantai China The 94362th Unit of People’s Liberation Army Qingdao China school of Information science and technology Beijing Institute of Technology Beijing China

When the initial frequencies and chirp rates of multi-component linear frequency modulation (LFM or chirp) signals are close,the signals may not be distinguished in the fractional Fourier domain (FRFD).Consequently,some signals cannot be *** this paper,first,the spectral distribution characteristics of a continuous LFM signal in the FRFD are analyzed,and then the spectral distribution characteristics of a LFM signal in the discrete FRFD are ***,the critical resolution distance between the peaks of two LFM signals in the FRFD is deduced,and the relationship between the dimensional normalization parameter and the distance between two LFM signals in the FRFD is also *** is discovered that selecting a proper dimensional normalization parameter can increase the ***,a method to select the parameter is proposed,which can improve the resolution ability of the fractional Fourier transform (FRFT).Its effectiveness is verified by simulation results.

关键词： fractional Fourier transform LFM signal signal resolution

Image stylization with enhanced structure on GPU

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science china(Information sciences) 2012年第5期55卷 1093-1105页

作者： LI Ping 1,SUN HanQiu 1,SHENG Bin 1,2 & SHEN JianBing 3 1 Department of Computer science and Engineering,The Chinese University of Hong Kong,Hong Kong,china 2 Department of Computer science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,china 3 school of Computer science and technology,beijing institute of technology,beijing 100081,china Department of Computer science and Engineering The Chinese University of Hong Kong Hong Kong China Department of Computer science and Engineering Shanghai Jiao Tong University Shanghai China school of Computer science and technology Beijing Institute of Technology Beijing China

This paper presents a graphics processing unit (GPU) based stylization approach that preserves the fine structure between the original and the stylized images using gradient *** abstraction and painterly stylization methods focused on contrast manipulation only,and thus the detailed salient structures of the input images are always destroyed when performing the current stylization techniques because of limitations like unavoidable salience information loss caused by contrast *** propose an image structure map to naturally model the fine structure existing in the original ***-based structure tangent generation and tangent-guided image morphology are used to construct the structure *** image structure map,unlike an edge map,not only systematically models the boundary information within the imagery but also accentuates the underlying inner structure detail for further *** facilitate the final stylization via parallel bilateral grid and structure-aware stylizing optimization on a GPU-CUDA platform in real *** multiple experiments,the proposed method consistently demonstrates efficient and high quality image stylization performance.

关键词： image stylization non-photorealistic rendering real-time processing GPU image abstraction

非完整力学系统的非Noether守恒量——Hojman守恒量

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物理学报 2004年第3期53卷 666-670页

作者：罗绍凯梅凤翔浙江工程学院数学力学与数学物理研究所北京理工大学理学院北京100081

研究非完整力学系统的非Noether守恒量———Hojman守恒量 .在时间不变的特殊Lie对称变换下 ,给出非完整力学系统的Lie对称性确定方程、约束限制方程和附加限制方程 ,得到相应完整系统的Hojman守恒量以及非完整系统的弱Hojman守恒量和强... 详细信息

研究非完整力学系统的非Noether守恒量———Hojman守恒量 .在时间不变的特殊Lie对称变换下 ,给出非完整力学系统的Lie对称性确定方程、约束限制方程和附加限制方程 ,得到相应完整系统的Hojman守恒量以及非完整系统的弱Hojman守恒量和强Hojman守恒量 .

关键词：分析力学非完整系统 Lie对称性非Noether守恒量 Hojman守恒量对称变换约束限制方程附加限制方程

Geomagnetic anomalies recorded in L9 of the Songjiadian loess section in southeastern Chinese Loess Plateau

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Geomagnetic anomalies recorded in L9 of the Songjiadian loes...

低温时效处理对铁磁形状记忆合金Mn_2NiGa的结构、相变和磁性能的影响

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： WANG DaoJing~(1*),WANG YongCheng~2,HAN JingTai~1,DUAN MuGang~3,SHAN JiaZeng~1 & LIU TungSheng~1 1 Key Laboratory ofCenozoic Geology and Environment,institute of Geology and Geophysics,Chinese Academy of sciences,beijing 100029,china 2 china University ofGeosciences,beijing 100083,china 3 school of Information science and technology,beijing institute of technology,beijing 100081,china

Detailed magnetostratigraphic and rock magnetic investigations on L8-S12 of the Songjiadian loess section in the Sanmenxia area, southernmost margin of the Chinese Loess Plateau were conducted in this ***/Brunhes(M/B) boundary occurred at the bottom of the loess unit *** top and bottom boundaries of the Jaramillo polarity subchron are found in the middle of L10 and the bottom of L12,*** fabric of the loess layers maintains the original depositional features and the recorded remanent magnetization analysis indicates little post-deposition disturbance *** late Matuyama chron,two anomalies of geomagnetic field have been detected in *** data demonstrated that these recorded anomalies were less likely a result of remagnetization,but more possibly the signature of geomagnetic excursions occurred,named SJD1 and *** is calculated that the midpoint ages of SJD1 and SJD2 are 0.917 Ma and 0.875 Ma,respectively,and the time-interval between the two events approximates 12 ***,SJD1 is close to the Santa Rosa(0.922 Ma) and SJD2 corresponds to the Kamikatsura (0.886 Ma) *** consistence with previous studies,the geomagnetic field was weakened during these events.

关键词： Paleomagnetism polarity event loess Sanmenxia

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物理学报 2011年第7期60卷 692-699页

作者：宋瑞宁李祥朱伟刘恩克李贵江蔡金芳王文洪吴光恒中国科学院物理研究所磁学国家重点实验室北京100190 北京理工大学材料科学与工程学院北京100081 北京理工大学理学院北京100081

对在较低温度范围的时效处理铁磁形状记忆合金Mn2NiGa的结构、相变和磁性进行了研究.研究发现,母相基体析出了细小的析出相,引起了晶格扭曲和畸变,导致了系统内产生了很大的内应力.在其浓度超过晶格的容忍度之后,提升了体系的马氏体相... 详细信息

对在较低温度范围的时效处理铁磁形状记忆合金Mn2NiGa的结构、相变和磁性进行了研究.研究发现,母相基体析出了细小的析出相,引起了晶格扭曲和畸变,导致了系统内产生了很大的内应力.在其浓度超过晶格的容忍度之后,提升了体系的马氏体相变温度,使母相在时效温度下转变成马氏体相,并在其中测量到高达900Oe的矫顽力.由于这种马氏体相的逆相变温度大幅提高,外推获得其居里温度在530K附近.细小析出相的粗化使内应力消失,样品又回到母相状态.观察到细小析出相粗化的两个阈值温度,分别为423K和485K.

关键词：铁磁形状记忆合金 Mn2NiGa 时效处理内应力

Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma school of Computer science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

Chaotic attitude and reorientation maneuver for completely liquid-filled spacecraft with flexible appendage

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Acta Mechanica Sinica 2009年第2期25卷 271-277页

作者： B. Yue Department of Mechanics, school of science,beijing institute of technology, 100081 beijing, china Department of Mechanics School of Science Beijing Institute of Technology

The present paper investigates the chaotic attitude dynamics and reorientation maneuver for completely viscous liquid-filled spacecraft with flexible appendage. All of the equations of motion are derived by using Lagrangian mechanics and then transformed into a form consisting of an unperturbed part plus perturbed terms so that the system＇s nonlinear characteristics can be exploited in phase space. Emphases are laid on the chaotic attitude dynamics produced from certain sets of physical parameter values of the spacecraft when energy dissipation acts to derive the body from minor to major axis spin. Numerical solutions of these equations show that the attitude dynamics of liquid-filled flexible spacecraft possesses characteristics common to random, non- periodic solutions and chaos, and it is demonstrated that the desired reorientation maneuver is guaranteed by using a pair of thruster impulses. The control strategy for reorientation maneuver is designed and the numerical simulation results are presented for both the uncontrolled and controlled spins transition.

关键词： Nonlinear attitude dynamics Attitude reorientation maneuver Control strategyLiquid-filled spacecraft

The effects of relative density of metal foams on the stresses and deformation of beam under bending

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Acta Mechanica Sinica 2007年第4期23卷 409-414页

作者： Aiyu Zhu Tianyou Fan Department of Mathematics,school of science,beijing institute of technology,P.O.Box 327,beijing 100081,china Department of Physics,school of science,beijing institute of technology,P.O.Box 327,beijing 100081,china Department of Mathematics School of Science Beijing Institute of Technology Department of Physics School of Science Beijing Institute of Technology

The exact analytic solution of the pure bending beam of metallic foams is given. The effects of relative density of the material on stresses and deformation are revealed with the Triantafillou and Gibson constitutive law （TG model） taken as the analysis basis. Several examples for individual foams are discussed, showing the importance of compressibility of the cellular materials. One of the objects of this study is to generalize Hill＇s solution for incompressible plasticity to the case of compressible plasticity, and a kinematics parameter is brought into the analysis so that the velocity field can be determined.

关键词： Metal foams - Relative density Compressible plasticity Constitutive law - TG model