Including importances in OWA aggregations using fuzzy systemsmodeling

Ordered weighted averaging (OWA) operators are described and are shown to provide a general class of parameterized aggregation operators that include the max, min, and average. We suggest an approach to the inclusion of importances in the OWA operator aggregation technique. The methodology suggested involves a transformation of the scores to be aggregated by their respective importances. We show how we can construct transformation functions with the aid of the fuzzy modeling technology     

Swarm aggregations using artificial potentials and sliding-mode control

In this paper, we consider a control strategy of multiagent systems, or simply, swarms, based on artificial potential functions and the sliding-mode control technique. First, we briefly discuss a "kinematic" swarm model in n-dimensional space introduced in an earlier paper. In that model, the interindividual interactions are based on artificial potential functions, and the motion of the individuals is along the negative gradient of the combined potential. After that, we consider a general model for vehicle dynamics of each agent (swarm member), and use sliding-mode control theory to force their motion to obey the dynamics of the kinematic model. In this context, the results for the initial model serve as a "proof of concept" for multiagent coordination and control (swarm aggregation), whereas the present results serve as a possible implementation method for engineering swarms with given vehicle dynamics. The presented control scheme is robust with respect to disturbances and system uncertainties.     

Adaptive disparity computation using local and non-local cost aggregations

A new method is proposed to adaptively compute the disparity of stereo matching by choosing one of the alternative disparities from local and non-local disparity maps. The initial two disparity maps can be obtained from state-of-the-art local and non-local stereo algorithms. Then, the more reasonable disparity is selected. We propose two strategies to select the disparity. One is based on the magnitude of the gradient in the left image, which is simple and fast. The other utilizes the fusion move to combine the two proposal labelings (disparity maps) in a theoretically sound manner, which is more accurate. Finally, we propose a texture-based sub-pixel refinement to refine the disparity map. Experimental results using Middlebury datasets demonstrate that the two proposed selection strategies both perform better than individual local or non-local algorithms. Moreover, the proposed method is compatible with many local and non-local algorithms that are widely used in stereo matching.     

Streaming data reduction using low-memory factored representations

Many special purpose algorithms exist for extracting information from streaming data. Constraints are imposed on the total memory and on the average processing time per data item. These constraints are usually satisfied by deciding in advance the kind of information one wishes to extract, and then extracting only the data relevant for that goal. Here, we propose a general data representation that can be computed using modest memory requirements with limited processing power per data item, and yet permits the application of an arbitrary data mining algorithm chosen and/or adjusted after the data collection process has begun. The new representation allows for the at-once analysis of a significantly larger number of data items than would be possible using the original representation of the data. The method depends on a rapid computation of a factored form of the original data set. The method is illustrated with two real datasets, one with dense and one with sparse attribute values.     

基于实时流协议的流媒体客户端

介绍了实时流和实时流协议，针对基于实时协议的流媒体客户端播放器的特殊要求，提出了一种适用于视频点播（Video On Demand)的流媒体客户端结构模型，研究并设计了相应的流量控制策略、组包算法和缓存管理策略，试验结果表明，该客户端播放器占用系统资源少，具有良好的实时性、容错性和同步性。     

Swarm aggregations of heterogeneous multi-agent systems

This paper investigates the problem of swarm aggregations of heterogeneous multi-agent systems. Comparing with the existing studies on swarm aggregations of homogeneous multi-agent systems, this paper is much more resembling the practical situations, where the agents have different dynamics. We show that the heterogeneous agents will gather with a certain error under some assumptions and conditions. The stability properties have been proven by theoretical analysis and verified via numerical simulation. The stability of the heterogeneous multi-agent systems has been achieved based on matrix theory and the Lyapunov stability theorem. Numerical simulation is given to demonstrate the effectiveness of the theoretical result.     

流媒体缓存代理单一流映像机制与流预取策略研究

为了解决传统的流媒体服务模式（客户端/服务器）中存在的流媒体服务器负载重、客户端播放抖动频繁等问题,本文详细研究了实现流媒体缓存代理的单一流映像机制,并针对缓存代理端的接收和发送阶段提出了实现这一机制的相关算法.同时在深入研究流预取理论模型的基础上,创新性地提出了基于RTCP包反馈和RTP包网络延迟的流预取策略,从而保证了客户端的播放质量.测试表明单一流映像机制的正确性和流预取策略的高效性.     

基于Spark Streaming的流式并行文本校对

互联网的高速发展催生了海量网络文本,这对传统的串行文本校对算法提出了新的性能挑战。尽管近年来文本自动校对任务受到了较多关注,但相关研究工作多集中于串行算法,鲜有涉及校对的并行化。文中首先对串行校对算法进行泛化,给出一种串行校对的通用框架,然后针对串行校对算法处理大规模文本存在的耗时长的不足,提出3种通用的文本校对并行化方法:1)基于多线程的线程并行校对,它基于线程池的方式实现段落和校对功能的同时并行;2)基于Spark MapReduce的批处理并行校对,它通过RDD并行计算的方式实现段落的并行校对;3)基于Spark Streaming流式计算框架的流式并行校对,它通过将文本流的实时计算转为一系列小规模的基于时间分片的批处理作业,有效避免了固定开销,显著缩短了校对时延。由于流式计算兼有低时延和高吞吐的优势,文中最后选用流式校对来构建并行校对系统。性能对比实验表明,线程并行适合校对小规模文本,批处理并行适合大规模文本的离线校对,流式并行校对有效减少了约110s的固定时延,相比批处理校对,采用Streaming计算框架的流式校对取得了极大的性能提升。     

Optimizing spatial Min/Max aggregations

Aggregate computation over a collection of spatial objects appears in many real-life applications. Aggregates are computed on values (weights) associated with spatial objects, for example, the temperature or rainfall over the area covered by the object. In this paper we concentrate on MIN/MAX aggregations: given a query rectangle, find the minimum/maximum weight among all objects intersecting the query rectangle. Traditionally such queries have been performed as range searches. Assuming that objects are indexed by a spatial access method (SAM), the MIN/MAX is computed while retrieving those objects intersecting the query interval. This requires effort proportional to the number of objects satisfying the query, which may be large. A better approach is to maintain aggregate information among the index nodes of the spatial access method; then various index paths can be eliminated during the range search. Yet another approach is to build a specialized index that maintains the aggregate incrementally. We propose four novel optimizations for improving the performance of MIN/MAX queries when an index structure (traditional or specialized) is present. Moreover, we introduce the MR-tree, an R-tree-like dynamic specialized index that incorporates all four optimizations. Our experiments show that the MR-tree offers drastic performance improvement over previous solutions. As a byproduct of this work we present an optimized version of the MSB-tree, an index that has been proposed for the MIN/MAX computation over 1D interval objects.Received: 5 September 2003, Published online: 24 February 2005Edited by: T. ÖzsuVassilis J. Tsotras: This research was supported by NSF Grants IIS-9907477, EIA-9983445, and IIS-0070135 and by the Department of Defense. Correspondence to: D. Zhang     

流式与非流式传输技术分析

流式传输与非流式传输技术是目前网络视频点播所采用的传输技术，本文简要介绍了这两种技术，并针对这两种技术作了分析和比较，最后就解决这两种技术和存在的问题提出了自己的新观点。     

Greedily computing associative aggregations on sliding windows

We present an algorithm for combining the elements of subsequences of a sequence with an associative operator. The subsequences are given by a sliding window of varying size. Our algorithm is greedy and computes the result with the minimal number of operator applications.     

基于无线移动流媒体技术在电视视频中应用研究

提出了用无线移动流媒体技术实现移动视频流.首先着重分析-324M的系统结构,从音频和视频等方面分析了传输方式和传输效率;最后用实验证明了该协议的高效传输,移动流媒体首选的 网络视频直播技术.     

Tessellated Shading Streaming

Presenting high‐fidelity 3D content on compact portable devices with low computational power is challenging. Smartphones, tablets and head‐mounted displays (HMDs) suffer from thermal and battery‐life constraints and thus cannot match the render quality of desktop PCs and laptops. Streaming rendering enables to show high‐quality content but can suffer from potentially high latency. We propose an approach to efficiently capture shading samples in object space and packing them into a texture. Streaming this texture to the client, we support temporal frame up‐sampling with high fidelity, low latency and high mobility. We introduce two novel sample distribution strategies and a novel triangle representation in the shading atlas space. Since such a system requires dynamic parallelism, we propose an implementation exploiting the power of hardware‐accelerated tessellation stages. Our approach allows fast de‐coding and rendering of extrapolated views on a client device by using hardware‐accelerated interpolation between shading samples and a set of potentially visible geometry. A comparison to existing shading methods shows that our sample distributions allow better client shading quality than previous atlas streaming approaches and outperforms image‐based methods in all relevant aspects.     

流媒体传输技术

文中主要对流媒体传输技术的发展现状进行了研究。首先,分别介绍了RTSP/RTP、HTTP渐进式下载以及自适应传输技术并从实现难易度、支持业务及实时性等方面对这三种流媒体传输技术进行对比;其次,对现存的自适应流媒体传输技术提出新的分类方式：推式流媒体传输和拉式流媒体传输,详细分析了两类自适应传输关键技术,给出了相应的实例分析,并对两类自适应传输技术进行对比;再次,介绍了基于可分级视频编码的自适应传输技术;最后,对最新的流媒体传输实例进行详细的介绍。     

流媒体自适应传输策略

本文阐述了在互联网环境下进行实时流媒体传输的技术以及面临的困难,阐述了AIMD算法的特点,并且改进了该算法使之更适应于流媒体传输。     

Streaming tape backup

As Winchester-based micros replace minicomputers in small and medium-sized businesses, the need for efficient data backup becomes crucial. Both floppy discs and removable Winchesters have drawbacks as backup media. Instead, as the article describes, streaming tape is a cost-effective and fast option. The characteristics of streaming tape systems and progress on standardizing protocols are discussed.     

基于内容感知的视频流媒体渐进式流传输方式

为有效利用传输网络带宽、平衡播出视频质量与用户等待时间之间的矛盾,提出一种基于内容感知的视频流媒体渐进式流传输方式。在视频内容分析和理解的基础上,根据编码关键参数确定视频序列中各帧的重要性,估计帧内片层数据重要性。采用MGS编码,在MobileIP测试平台上进行实验。实验结果表明了该传输方式的正确性和有效性,能够适应网络带宽和质量可伸缩的视频流媒体。     

Tracking multiple features using relaxation

A new algorithm is introduced for tracking multiple features in an image sequence. First, the proposed method iteratively reduces the disparity of each possible match by relaxation labeling. It is assumed that all trajectories are smooth and the smoothness is used as the measure for correspondence. Some cases of wrong correspondences can be recovered by a proposed scheme called constraint-aided exchange during the tracking process. Occluded or missing feature points can be detected and predicted in the proposed algorithm. Finally, the algorithm is applied to data obtained from real world scenes. The human motion analysis can be achieved by the tracking algorithm.