三维流场的流线深度特征学习与特征聚类

流场可视化指将流体运动的数据转换为视觉形式,以便更好地理解和分析流场的流动。利用流线来实现流场可视化,是当前最为热门的方法。文中提出了一种学习、聚类三维流场流线特性的方法。首先设计了一种基于卷积的自编码器来提取流线特征。该方法中的自编码器由编码器和解码器组成,其中编码器用卷积层降维的方式来提取输入流线的特征,而解码器使用转置卷积对流线特征进行上采样,以此重建流线。通过训练不断减小输入流线与重建流线的差异,可以让编码器提取到的流线特征更加准确。其次,改进了CFSFDP算法,用于流线特征聚类。针对原CFSFDP算法需要手动选取聚类中心,以及对距离参数过于敏感的缺点,改进了其指标计算方法,实现对聚类中心的自动选取,并且引入了高斯核密度估计,实现对截断距离参数的自适应计算。实验结果表明,所提方法在流线特征的学习以及聚类上具有良好的效果。

北京地铁站厅闸机设置的调研与分析

以北京地铁4号线大兴线、5号线、8号线、10号线等市区新建线非换乘站站厅为研究对象,以闸机设置与客流流线关系为区分点,分析了各种类型地铁站厅的优缺点,探讨了闸机与其他设施的相对布局、闸机的数量与客流疏解能力的关系,给出闸机布局分类和动物园站闸机布局优化方案,为北京地铁站厅类别划分与新线站厅设计提供可行的建议。

天津站枢纽客运组织方案的研究和思考

天津站交通枢纽由天津城市轨道交通2、3、9号线的地下段,京津城际铁路和国铁交汇组成,具有工程结构复杂、客流量大且交叉明显等特点。从枢纽的工程设计、客流预测、流线特征分析等入手,阐述天津站枢纽的客运组织特点、原则、要求和具体措施,提出完善枢纽导向系统、构建一体化枢纽运营管理模式及与周边协调发展的优化思路。

耗材摩擦焊中的耗材过渡与成形机理研究

以 1 Cr1 8Ni9Ti为耗材在低碳钢母材表面进行了摩擦焊敷试验。观察测量了不同工艺参数匹配下耗材金属的过渡行为和真实接触面的大小 ,阐明了耗材金属的过渡机理和真实接触面的变化规律及影响因素 ;以特征流线为依据 ,建立了过渡金属形成初始焊敷层的物理模型并分析了摩擦碾压作用对焊敷层最终成形和界面连接过程的影响。研究表明 ,耗材金属是通过真实接触面过渡到母材表面的 ,真实接触面位于旋转界面的中心区域 ,其大小随耗材转速和摩擦压力的增大而减小 ;真实接触面两侧不对称的温度分布是推动耗材金属过渡的驱动力 ;摩擦碾压作用是焊敷层最终成形和界面形成可靠连接的决定因素。

The complex nonlinear systems with fractal as well as chaotic dynamics of annual runoff processes in the three headwaters of the Tarim River

This paper attempted to identify fractal and chaotic characteristics of the annual runoff processes in headwaters of the Tarim River.Methods of fractal analyses were used to explore several aspects of the temporal changes from 1957 to 2002.The main findings are as follows:(1) The annual runoff processes of the three headwaters of the Tarim River are com-plex nonlinear systems with fractal as well as chaotic dynamics.(2) The correlation dimensions of attractor derived from the time series of the annual runoff for the Hotan,Yarkand and Aksu rivers are all greater than 3.0 and non-integral,implying that all three rivers are chaotic dynamical systems that are sensitive to initial conditions,and the dynamic modeling of their annual runoff process requires at least four independent variables.(3) The time series of annual runoff in each river presents a long-term correlation characteristic.The Hurst exponent for the period of 1989 to 2002 suggests that we may expect to see an increasing trend in the annual runoff of the Aksu and Yarkand rivers in the years after 2002,but a decreasing tendency for the Hotan River in the same period.

Traffic Characteristics Based Dynamic Radio Resource Management in Heterogeneous Wireless Networks

The traffic with tidal phenomenon in Heterogeneous Wireless Networks(HWNs)has radically increased the complexity of radio resource management and its performance analysis.In this paper,a Simplified Dynamic Hierarchy Resource Management(SDHRM)algorithm exploiting the resources dynamically and intelligently is proposed with the consideration of tidal traffic.In network-level resource allocation,the proposed algorithm first adopts wavelet neural network to forecast the traffic of each sub-area and then allocates the resources to those sub-areas to maximise the network utility.In connection-level network selection,based on the above resource allocation and the pre-defined QoS requirement,three typical network selection policies are provided to assign traffic flow to the most appropriate network.Furthermore,based on multidimensional Markov model,we analyse the performance of SDHRM in HWNs with heavy tailed traffic.Numerical results show that our theoretical values coincide with the simulation results and the SDHRM can improve the resource utilization.

PROJECTION BASED STATISTICAL FEATURE EXTRACTION WITH MULTISPECTRAL IMAGES AND ITS APPLICATIONS ON THE YELLOW RIVER MAINSTREAM LINE DETECTION

Mainstream line is significant for the Yellow River situation forecasting and flood control.An effective statistical feature extraction method is proposed in this paper.In this method, a between-class scattering matrix based projection algorithm is performed to maximize between-class differences, obtaining effective component for classification;then high-order statistics are utilized as the features to describe the mainstream line in the principal component obtained.Experiments are performed to verify the applicability of the algorithm.The results both on synthesized and real scenes indicate that this approach could extract the mainstream line of the Yellow River automatically, and has a high precision in mainstream line detection.

Technology Embedded Imagination for Arab Women

With advancing channels of communication easing the availability of technological tools, the young minds of women in the Arabian Peninsula are ready to adopt forthcoming challenges. The embrace of storytelling in the digital realm by these young minds reflects the interplay of traditional culture, western modernism, and changes brought about by media industries. These women have adopted and used new media as a vehicle to maneuver their interesting and fresh ideas and have seen the rectilinear screen of a computer as an exit through which to come out and say something to the masses. The thinking methodology has culminated in pragmatic and dynamic visuals in order to celebrate, inform, and create awareness about the issues that they see in the region and among the people. With this freedom of expression, they are creating a new visual culture and transforming themselves into a meaningful workforce. With emerging technological tools, they blend intuitive, pragmatic, emotional, and contextual imagination with a highly-sophisticated production pipeline in order to incorporate the challenges of synthesizing ＂dialect＂ and ＂codes＂ that have traditionally been segregated in the culture. Their work is an amalgamation of arts/design, animation, life footage, and meaningful communication. With cyclical evaluation, they entwine the two elements, creativity, and technicality with massive exposure of Digital Assists Management （DAM）. This paper explains how current technological tools and contextualized teaching instructions foster meaningful content with the elicitation and mergence of Arab anthropological characteristics.

Nonlinear morphological characteristics of debris flow in Dongcheng area of Helong,Jilin

Helong City is located in the northeastern Changbai Mountain with a poor geological environment,there often occur debris flows,collapses and landslides;especially debris flows restrict the local economic development. Based on fractal theory and the surveying data of 34 debris flows,the authors studied fractal feature of debris flow gully and its various situations of fractal dimensions in different observation scales. The nonlinear relation reveals the development of non-uniformity and self similarity of debris flow gully.

Investigations on pool boiling critical heat flux, transient characteristics and bonding strength of heater wire with aqua based reduced graphene oxide nanofluids

In the present work, the pool boiling critical heat flux, transient heat transfer characteristics, and bonding strength of thin Ni-Cr wire with aqua based reduced graphene oxide(r GO) nanofluids are experimentally studied. Results indicate:(i) the critical heat flux(CHF) of 0.01, 0.05, 0.1, 0.2, and 0.3 g·L^(-1) concentrations of r GO-water nanofluids varies from 1.42 to 2.40 MW·m^(-2);(ii) the CHF remains same for the tested samples during transient heat transfer studies and(iii) a constant value of CHF upto 10 tests when the nanocoated Ni-Cr wire is tested with DI water and deterioration occurs beyond this which implies a chance of peel off of r GO layer below the critical coating thickness.

Mixing and Recirculation Characteristics of A Double Concentric Burner with Bluff-Body

The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates, by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a double concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(U_s/U_p)of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for observing the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.