欢迎批评指正。 Velocity–vorticity correlation structure in turbulent channel flow Jun Chen,Fazle Hussain,Jie Pei and Zhen-Su She (2014). Journal of Fluid Mechanics Volume 742 , March 2014 pp 291-307 http://journals.cambridge.org/action/displayAbstract?aid=9179891
ABSTRACT Flow Mapping, also known as spatial interaction data visualization, has become widely used for exploratory spatio-temporal data analysis to understand complex spatial phenomena such as human migration, commercial trading, and social networks. The unitary flow mapping architecture, in which data storing, computing and representation are deployed in a single computer, is facing the challenges being brought from increasing data scale, higher timing demand, computing complexity of visual clutter detecting and integrating with other GIS and spatio-temporal analysis tools. In this paper, a novel 3-tiers flow mapping service architecture is proposed. In this architecture, flow data integration tier provide a unified data access interface for variant data sources; flow mapping models tier provide a computing resource pool to support different flow mapping algorithms and scalable computing capability; and result visualization tier to view map interactively. In this paper, we expand the OGC Web Map Services(WMS) standard protocol to support spatio-temporal interaction data visualization and analytics, and integrate WMS-based flow mapping service with other map resources by JavaScript toolkits in browsers. This architecture is validate to be improved in performance and scalability by three typical application cases. 1. Guo, D., et al. WMS-Based Flow Mapping Services. in Services (SERVICES), 2012 IEEE Eighth World Congress. 2012. 全文下载： WMS-based FM services.pdf
Zengsheng Ma, Shiguo Long , Yong Pan, Yichun Zhou Nanoindentation tests in Ni thin films with 3000 nm thickness were performed under the maximum load ranging from 1000 to 9000 m N to investigate the dependence of the Flow stress and Young’s modulus upon the indentation scale under zero and 10% tensile strain. The results show that, the Flow stress and Young’s modulus all display the indentation depth dependence. Furthermore, an analytical relationship between the Young’s modulus E and hardness H for Ni thin films is established based on the conventional depth-sensing indentation method of Oliver and Pharr. ICHMM2008, 195-199, (ISTP) Flow stress and Young's modulus of Ni films in nanoindentation creep.pdf
Traffic and Granular Flow '11 28 September - 01 October, 2011 Uzkoe, Moscow, Russia Russian Academy of Sciences Call for papers Paper Submission Deadline: April 30, 2011 TGF'11 The Ninth international Conference on Traffic and Granular Flow '11 September 28 - October 1, 2011, Moscow, RUSSIA The Conference on Traffic and Granular Flow '11 (TGF'11) is the ninhth of an international series of conferences held previously in Jülich (1995), Duisburg (1997), Stuttgart (1999), Nagoya (2001), Delft (2003), Berlin (2005), Paris (2007) and Shanghai (2009). TGF'11 will be held in Moscow, Russia. Moscow is the biggest city and the largest commercial and financial center in Russia, is also the center of research in traffic dynamics and related fields. TGF'11 will take place in the Uzkoe Hotel of Russian Academy of Science, Moscow, Russia. The purpose of this conference is to facilitate new ideas by considering the similarities of traffic and granular flow. Recent achievements in modeling, computer simulation and phenomenology will be presented, and possible future applications in traffic control and creation of ITSs will be discussed. Topics include highway traffic flow, granular flow, traffic on Internet networks, and pedestrian dynamics as well as collective dynamics of biological systems. The importance of exploring the interrelations between these fields is constantly increasing. This conference offers the opportunity to stimulate interdisciplinary research, exchange ideas, and meet many experts in these areas of research. Conference Organizers · Keldysh Institute of Applied Mathematics (Russian Academy Of Science) · Moscow Technical University of Communications and Informatics Sponsors · Russian Academy of Science · Russian Foundation for Basic Research Topics · Highway and urban vehicular traffic · Pedestrian traffic and evacuation dynamics · Granular flow · Collective motion in biological systems · Complex networks: transportation networks, internet, epidemics, social networks.. · Cellular automata applied to the above fields · Intelligent Traffic Systems (ITS) Submission of papers: Contributors are invited to submit their manuscripts online. Use this form to upload papers: Open form Main information Title of the paper Keywords (please enter a maximum of 5 keywords) Name of the Contact Author Email of the Contact Author Select your file here: Author(s) Author's name Author's affiliation Author's postal address Author's email Author's name here Add author CAPTCHA Enter the characters shown in the picture below: ( refresh ) Contributions must be uploaded to the evaluation website by April 30, 2011 in either DOC, DOCX or PDF formats. Submission implies that the manuscript has not been published previously, and is not currently submitted for publication elsewhere. The first page of the paper should specify: title of the paper, name of the author(s) and their affiliation, postal address and email address for each author as well as the name of the Contact Author and a maximum of 5 topical keywords that would best represent the content of the paper. Please cite the name of the Conference on the first page. Welcome to Moscow! Best regards, Chair of Program Committee Acad. of RAS V. V. Kozlov (Vice President, Presidium of Russian Academy of Sciences, Russia) Chair of Organizing Committee Acad. of RAS A. S. Bugaev (Head of Department, MIPT, Russia)
http://www.flowthefilm.com/trailer About the Film Irena Salina's award-winning documentary investigation into what experts label the most important political and environmental issue of the 21st Century - The World Water Crisis. Salina builds a case against the growing privatization of the world's dwindling fresh water supply with an unflinching focus on politics, pollution, human rights, and the emergence of a domineering world water cartel. Interviews with scientists and activists intelligently reveal the rapidly building crisis, at both the global and human scale, and the film introduces many of the governmental and corporate culprits behind the water grab, while begging the question "CAN ANYONE REALLY OWN WATER?" Beyond identifying the problem, FLOW also gives viewers a look at the people and institutions providing practical solutions to the water crisis and those developing new technologies, which are fast becoming blueprints for a successful global and economic turnaround. On December 10th, 2008 FLOW was invited to screen at the United Nations as part of the 60th Anniversary of the Declaration of Human Rights. Watch the video here: FLOW at the UN
2010, Proceedings of the 36th International MATADOR Conference , 6 , Pages 227-230 Modeling of hard turning: effect of tool geometry on cutting force Z.Y. Shi, Z.Q. Liu, C.M. Cao Abstract. Hard machining for manufacturing dies and molds offers various advantages, but the productivity is often limited, mainly by tool life. This study investigates the influence of cutting tool geometry on the cutting forces by utilizing finite element simulations (FEM). A set of cutting conditions in numerical FEM were conducted by using four different shaped cutting tools and axial force, radial force and tangential force were found. The results of this research help to explain the conclusion that for cylindrical control, the equation of the actual geometry of the S-shaped inserts involved in cutting is a sphere; that of C-shaped, D-shaped and Tshaped inserts involved in cutting is an ellipsoid with different lengths of short-half axis. Keywords : tool geometry, material flow stress, short-half-axial, cutting force FULL TEXT
2006年的时候，做人脸跟踪AAM项目，参考了一篇叫做“L-K算法20年”的文章 ，看得不知所云。现在再看，觉得他们有故弄玄虚的意思。比如说，既然大家都在Tamplate上计算梯度下降，那为什么还要讲那么多正向warp，反向warp的。反正当时是看得恶心了。我还是按自己的理解写写吧，也许写得不对，请大家指正。 L-K算法（或称光流法）本质上是一种基于梯度下降的优化方法。对于梯度下降法我的理解是这样： 对于一个标量函数y=f(x)，可以看作是一个曲线，在一个很小的范围内可以认为是直线（局部线性），求函数最小值的下降方向为梯度的负方向Δx=-Δy/tan(th)。对于一维函数梯度tan(th)=dy/dx，它的倒数很容易得到。而对于x是向量的情况，对应的梯度的"倒数"就变成求逆矩阵了。比如图像每个点的梯度(dI/dx,dI/dy)就是一个矢量，一个点求逆矩阵显然不可以，但是一个图像块内的N的点构成2*N矩阵，就可以求伪逆了（最小二乘法）。对于变量x是更高维的情况，比如函数y是和很多变量相关的，每个点的梯度dy/dx由变量x的每个分量有关，变成了高维矢量(dy/dxi)，尽管这时y和x的变化关系可能无法线性表达，但总是可以通过中间变量利用链式法则求dy/dx，或者利用数值法求解，比如给xi一个小的增量，y也相应产生一个增量，二者比值可以近似梯度矢量dy/dxi，这样仍然可以得到上边所说的Δx伪逆解。 实际上图像中的物体都可以表达为局部图像块的集合，比如利用三角剖分或者稀疏的特征点，对这些区域单独使用L-K算法，然后用全局的模型参数进行拟合（去除坏的匹配块），这样就有可能实现复杂的目标比如人脸图像的跟踪。著名的AAM人脸建模方法基本上就是这个思路。 具体算法的推导可参考我总结的文档 L-K算法文档 。 关于文档最后的那个方程组 Δp=dp*E 的说明： 1 图像和模板的差是图像匹配的原动力，它分别和 dP 矩阵中的的6个N维矢量做内积得到参数p的更新值 p=p+Δp ，从而驱动模板动起来。这个求解过程是个迭代过程，无法保证收敛到全局最优解。用多分辨率法求解是个好的选择，可参见OpenCV里的光流法文档。 2用来跟踪的光流法是用前一帧的图像块作为模板，用当前帧图像进行匹配的，这个过程要实时计算二阶逆矩阵（p的位数是2）。而在有些应用中， dP 的步骤可以只在模板T上离线进行，可称作训练。模板也可以扩展为一个包含更多参数的模型，比如著名的Active Appearance Model。有时warp过程无法显式表达，计算 dP 可以用给p加扰动(perturbation)的方法。CMU的文章把Cootes的那套AAM用L-K光流的框架来描述，据他们自称，电影Avatar就是用他们的方法做人脸特征跟踪的。 3 参考文章1中把H=J T J叫作Hessian矩阵，它是对J求伪逆过程的一个副产品，和表达二阶偏导的Hessian阵不同。不过H的作用很重要，它能反映图像数据的统计特性。如果不幸H是奇异的，也就是说无法求逆矩阵，那么说明这个图像模板包含的各个梯度方向的信息不足以进行跟踪应用。对于光流应用（p的维数是2，只有平移运动），H的对应的特征值(eigenvalue)都要远大于0，才是“好的特征”（角点），这个特性又被用来做corner detection。有著名的文章Good features to track专门讨论此事。 参考文献: Simon Baker and Iain Matthews. Lucas-Kanade 20 years on: A unifying framework. Jianbo Shi and Carlo Tomasi. Good features to track.
In mathematics a Vector field is a construction in vector calculus which associated a vector to every point in a subset of Euclidean space. Vector fields are often used in pysics to model, for example, the speed and direction of a moving fluid thoughout space, or the strength and direction of some force, such as the magnitic or gravitational force, as it changes from point to point.
标签: flow
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