Computational representation and analysis of emotion dynamics

Multimedia Tools and Applications - Human emotions are dynamic in nature. The intensity with which they are felt changes over time, and they have a natural timescale of expression, from onset to...     

Assessing the information content of multiangle satellite data for mapping biomes: I. Statistical analysis

The insights gained from present land cover classification activities suggest integration of multiangle data into classification attempts for future progress. Land cover types that exhibit distinct signatures in the space of remote sensing data facilitate unambiguous identification of cover types. In this first part, we develop a theme for consistency between cover type definitions, uniqueness of their signatures, and physics of the remote sensing data. The idea of angular signatures in spectral space is proposed to provide a cogent synthesis of information from spectral and angular domains. Three new metrics, angular signature slope (ASSI), length (ASLI), and intercept indices, are introduced to characterize biome signatures. The statistical analyses with these indices confirm the idea that incorporation of the directional variable should improve biome classification result. The consistency principle is tested with the Multiangle Imaging SpectroRadiometer (MISR) leaf area index (LAI) algorithm by examining retrievals when both unique and nonunique signatures are input together with a land cover map. It is shown that this requirement guarantees valid retrievals. Part II provides a theoretical basis for these concepts [Zhang et al., Remote Sens. Environ., in press.].     

Computational and structural analysis of the contour of graphs

Let be a finite, simple, and connected graph. The closed interval of a set is the set of all vertices lying on a shortest path between any pair of vertices of S. The set S is geodetic if . The eccentricity of a vertex v is the number of edges in the greatest shortest path between v and any vertex w of G. A vertex v is a contour vertex if no neighbor of v has eccentricity greater than v. The contour of G is the set formed by the contour vertices of G. We consider two problems: the problem of determining whether the contour of a graph class is geodetic; the problem of determining if there exists a graph such that is not geodetic. We obtain a sufficient condition that is useful for both problems; we prove a realization theorem related to problem and show two infinite families such that is not geodetic. Using computational tools, we establish the minimum graphs for which is not geodetic; and show that all graphs with , and all bipartite graphs with , are such that is geodetic.     

Development of a semantic-based content mapping mechanism for information retrieval

Most information retrieval systems use keywords entered by the user as the search criteria to find documents. However, the language used in documents is often complicated and ambiguous, and thus the results obtained by using keywords are often inaccurate. To address this problem, this study developed a semantic-based content mapping mechanism for an information retrieval system. This approach employs the semantic features and ontological structure of the content as the basis for constructing a content map, thus simplifying the search process and improving the accuracy of the returned results.     

密码协议形式化分析的计算合理性

基于Abadi-Rowgaway的形式化加密的计算合理性定理,提出和证明了密码协议形式化分析的计算合理性定理。通过对群密钥分配协议安全性的分析,说明定理对协议的可选择攻击具有较强的分析能力,提出了群密钥分配协议的形式化方法与计算方法下安全性的形式化定义,并证明了其合理性。     

花托自同构映射及其逆变换分析

花托自同构映射是一种变换技术, 尤其多被用于数字图像置乱。由于花托自同构映射变换在一定条件下具有周期性, 使得通过控制变换的次数可以实现还原。目前关于该变换的还原大都利用周期性进行, 但由于周期的无规律性以及还原过程的时间代价过高, 使得花托自同构映射的应用及推广受到很大限制。对花托变换的逆映射进行了研究：首先证明了变换是双射, 由此可知必然存在它的逆变换;接着给出了一般情况下的逆变换表达式;最后通过图形实验验证了逆变换还原对于周期性还原的优越性。     

Internet宏观拓扑的协议映射与分析

从协议角度,利用拓扑学和图论方法研究了Internet宏观拓扑的网络性能和形成机理。在给定Internet宏观拓扑的图论定义后,通过找到一个协议通信模式到Internet宏观拓扑的可行映射条件,进而分析了Internet宏观拓扑的连通度和平均拓扑距离。结果表明Internet宏观拓扑的形成机理源于协议的无限空间换取有限时间效应的设计原理,使得Internet可以实现实时通信,即在满足网络可靠性的同时,又保证网络的有效性。     

Spectral intensity mapping and analysis of dyed microflows

The objective of this work is to develop simple reliable software to observe and quantify diffusion phenomena in microfluidic devices. One of the great advantages of microfluidic technology is that it permits the flow and diffusion of multiple streams in a single channel. The accurate control of a diffusion-based process has applications in bioanalytical chemistry, production of organic compounds and combinatorial chemistry. This method has been discussed in the literature as laminar fluid diffusion interface technology. It is heavily dependant on the controlled and reproducible introduction of several fluids into one channel and enables the design of separation and detection systems based on laminar fluid diffusion interfaces. A method of analysing and interpreting the diffusion behaviour of multiple microflows using the MATLAB programming language as an image analysis tool is presented here. This paper considers two dimensional brightfield and time series images but the method can be applied to other forms, including fluorescent and three-dimensional images. The approach taken relies on the fact that a digital image stores its colour information in signal channels. The information contained in the channels depends on the colour method being used to define the image. Software-based spectral filtering is performed, yielding three-dimensional intensity maps of dyed and clear microflows. These maps can be used to monitor diffusion behaviour in a number of different areas simultaneously. Spectral noise reduction techniques are also incorporated without significant reduction in original data quality. The technique is used to determine the aqueous diffusion coefficient of the dye Green S by processing digital images taken at 2 s time intervals in a stopped-flow experiment. The approach is applied to microflows in straight, two-dimensional serpentine, and three-dimensional serpentine channel configurations.Presented at the 2nd International Conference on Microchannels and Minichannels, Rochester, New York, June 2004.     

Computational fluid dynamic analysis and design optimization of jet pumps

Jet pumps have a wide variety of applications and are commonly used in thermal power plants and refrigeration systems. An initial jet-pump design was developed using an analytical approach and its efficiency was improved using an efficient and accurate computational fluid dynamics model of the compressible turbulent flow in the pump, whose predictions agreed well with corresponding experimental data. Parametric studies were performed to determine the influence of the pump’s geometry on its performance and the high fidelity CFD solutions were used to build surrogate models of the pump’s behavior using the moving least squares method. Global optimization was carried out using the surrogates. This approach resulted in pump efficiency increasing from 29% to 33% and enabled the energy requirements of the pump to be reduced by over 20%.     

Computational Bayesian analysis of hidden Markov mesh models

Versions of the Gibbs sampler are derived for the analysis of data from the hidden Markov mesh random fields sometimes used in image analysis. This provides a numerical approach to the otherwise intractable Bayesian analysis of these problems. Detailed formulation is provided for particular examples based on Devijver's Markov mesh model (1988), and the BUGS package is used to do the computations. Theoretical aspects are discussed and a numerical study, based on image analysis, is reported     

Computational simulation and analysis of double-swept blade in BVI noise reduction

The TURNS computational fluid dynamics (CFD) code with the Beddoes prescribed wake and the WOPWOP computational acoustics code is used to study blade-sweep blade–vortex interaction (BVI) noise reduction design. The CFD three-dimensional unsteady solutions of blade surface pressure distributions are used as the input to WOPWOP acoustics computational code to produce the overall sound pressure level (OASPL) on a 3-rotor radiation observer hemisphere around the helicopter rotor. To study the effects of blade sweep on BVI noise reduction, computations are performed on a baseline rectangular blade and a corresponding double-swept blade to better understand the impact of blade sweep on BVI noise reduction in relation to the interaction angle between blade leading edge and the shed tip-vortex. The present study indicates that tip-region blade forward sweep produces favorable BVI angles for dominate BVIs to reduce the maximum BVI noise level on the advancing side, while increasing noise level on the retreating side. Increasing in the noise level on the retreating side as a trade-off for decreasing in the maximum noise level on the advancing side results favorably in the reduction of the overall maximum noise level and in changing the ‘hot’ noise spots into a more desirable ‘less hot’ noise region.     

Computational analysis of water residence on ceramide and sphingomyelin bilayer membranes

Many physical chemical properties of lipid membranes, for example, the thickness, phase state, order parameter, and fluidity, can be understood straightforwardly. Water residence on a membrane is, however, an exception. To tackle this problem, we have performed molecular dynamics simulations of the distribution of water normal to the surface of several lipid membranes and from this deduced the associated water residence time. Our analysis of the results clearly indicates that lipid membranes have hydration shells on their surface, just as a solute in an aqueous solution does, and that the water residence time can be estimated from the potential for the mean force field derived from the distribution function of the water. We have done this atomic-scale analysis for ceramide bilayers and contrasted the calculation results with those for sphingomyelin bilayers, revealing that sphingomyelin bilayers can retain water molecules longer than ceramide bilayers and that the total number of water molecules retained on the membrane surface of sphingomyelin is larger than that for ceramide. In addition, we find that not only polar atoms of lipid molecules, such as oxygen, but also non-polar atoms, such as carbon, influence the motion of water on the membranes.     

视频内容分析技术

概述了基于内容的视频检索的方法和工作过程,研究的重点是突变镜头探测(基于像素的方法、模板匹配法、基于直方图的方法、基于视频特征的方法),渐变镜头探测(双重比较法、基于模型的方法、基于压缩域的方法),关键帧提取的关键技术(基于颜色特征的方法,基于镜头边界的方法、基于镜头的方法、基于运动分析的方法等),在综合分析了各类方法的工作机理和优缺点的基础上,提出了一个优化的视频内容分析检索框架.     

基于XML实现Java内容仓库和关系型数据库的双向映射

提出了Java内容仓库和关系型数据库之间异构信息的双向映射机制的概念,利用XML作为Java内容仓库和关系型数据库的中间桥梁,充分发挥了Java内容仓库对大量文档信息的操作和数据库对关系数据信息操作之间的强大优势,成功解决了在仿真分析工程中,既能快速、高效地实现海量仿真数据的存储、添加、编辑、修改、删除等功能操作,也能快速、高效地实现仿真文件的上传、下载、删除等功能操作。     

Optical mapping and nanocoding approaches to whole-genome analysis

Recent application of microfluidic and nanofluidic approaches to genomics has enabled rapid analysis of whole human and other large genomes. Here, we present a review of optical mapping and nanocoding, two single-molecule whole-genome analysis systems, which are used for physical mapping of genomes. Optical mapping employs a microfluidic device, fabricated using soft lithography approaches, to achieve DNA presentation via DNA flow in microchannels. On the other hand, nanocoding leverages DNA confinement in nanoscale devices to achieve DNA presentation. In this review, we focus on the physical principles underlying DNA presentation in both of these systems and the application of these approaches towards better understanding of genomic structure and structural variation.