基于H.264的新型视频加密算法

本文提出了一种新的基于H.264标准的视频加密算法结构。使用改进的FMO机制(advanced-FMO mechanism)将具有相关性的宏块打入不同的Slice中,通过对FMO子图的加密达到对整个视频内容进行加密的目的。本文提出的加密算法具有很高的实时性,加密过程可以和编码过程并行执行。同时本算法还可以和传统的加扰算法结合,进一步提高视频的加密效果。     

TV-VGA视频转换中的降噪措施及硬件实现

为了满足图像实时处理时对速度的要求,以及适应能够同时抑制高斯噪声和脉冲噪声的需要,提出了一种简单有效的滤波方法一混合滤波。MATLAB上的算法仿真表明：通过将中值滤波器与均值滤波器级联,可以有效的滤除视频图像中的混合噪声（脉冲噪声和高斯噪声）。采用Verilog HDL对电路进行设计,并在Xilinx公司的Spartan-IIE系列芯片上实现了混合滤波器。此滤波器算法简单,便于硬件实现,可以应用于实时图像处理中。     

Efficient erasure correcting codes

We introduce a simple erasure recovery algorithm for codes derived from cascades of sparse bipartite graphs and analyze the algorithm by analyzing a corresponding discrete-time random process. As a result, we obtain a simple criterion involving the fractions of nodes of different degrees on both sides of the graph which is necessary and sufficient for the decoding process to finish successfully with high probability. By carefully designing these graphs we can construct for any given rate R and any given real number ϵ a family of linear codes of rate R which can be encoded in time proportional to ln(1/ϵ) times their block length n. Furthermore, a codeword can be recovered with high probability from a portion of its entries of length (1+ϵ)Rn or more. The recovery algorithm also runs in time proportional to n ln(1/ϵ). Our algorithms have been implemented and work well in practice; various implementation issues are discussed     

Balance of 0, 1 bits for Huffman and reversible variable-length coding

This letter proposes a novel algorithm to obtain a suboptimal solution for the balance of bit distribution after Huffman coding. The algorithm is simple, and can be embedded in the conventional Huffman coding process. In addition, the letter also discusses the bit-balance problem for reversible variable-length codes (RVLCs) based on Huffman coding. Analytical and experimental results suggest that the new algorithm is very useful in improving the 0/1 balance property for Huffman codes and RVLCs.     

TD-LTE下行链路波束赋形技术研究

在波束赋形系统模型和算法准则的基础之上,给出一种相对传统特征值分解方法有一定简化的算法。该方法能够有效克服波束赋形过程中复杂度较大且会引起系统延迟的问题。根据TD-LTE系统物理层协议规定生成信号源并进行建模,通过搭建完整的赋形链路来获得波束赋形的加权系数。在多径衰落信道下,对传统的基于QR分解的特征值分解算法和简化算法进行仿真分析。结果表明：在相同的仿真条件下,简化后算法能够在保持一定精度的基础上,复杂度降低为原来的1/60。     

TD-SCDMA系统中利用中置实现DOA检测的方法

智能天线的一项核心技术是来波方向（DOA）估计。设计物理模型清晰、数学运算复杂度低的DOA估计算法,对于智能天线的工程实现具有重要的意义。本文给出了一种利用TD-SCDMA标准中置序列在基带上实现DOA检测的简单实用的谱搜索方法 MIDOA谱搜索算法。文章首先给出了TD-SCDMA系统8阵元圆阵智能天线系统中置接收机的物理模型,在此基础上导出了与之相对应的数学处理模型,并根据这些数学模型导出了MIDOA谱搜索算法流程图和相应的基带检测MIDOA谱搜索算法。从仿真结果和性能分析可以看出该方法是一种针对TD-SCDMA标准的、简单有效的DOA估计方法;与基于子空间的Music等算法相比,它具有物理模型清晰、算法的稳健度高和可检测的DOA数不受智能天线阵元数的限制等特点。      

Fault-Tree Analysis Using a Binary Decision Tree

A new algorithm for the production of a short disjoint-products form of a fault-tree output function is presented and discussed. This algorithm consists of a sequential binary decision process to find first big, then smaller sets of elementary system-failure states which correspond to disjoint-product terms. The identification of bad and good system states can be eased by a simple ternary (3-state) decision for which an auxiliary procedure is presented. The main advantages of this algorithm appear to be its efficiency, simplicity, and usefulness as an alternative (in the sense of multiversion programming for software fault tolerance) for the Shannon decomposition algorithm.     

齐次F5算法的简单终止性证明

自从F5算法提出以来,出现了一批基于标签的Grbner基算法,它们使用了不同的选择策略且减少冗余多项式的准则也各不相同。为了满足正确终止性,这些算法的策略和准则必须满足一些一般的规律。根据这些规律,该文提出了一个框架,使大多数算法成为该框架的实例。随后,利用重写基的性质,得到了框架的简单正确终止证明。为了得到F5算法的简单证明,该文对F5算法的约化操作进行合理的化简。特别地,对于齐次F5算法,证明了其复杂的选择策略等价于按模序选择。这样,齐次F5算法就能看成框架的一个特例,从而得到了F5算法的简单证明。     

一种基于MBE的快速基音搜索算法研究

多带激励声码器(MBE)是目前理想的语音编码方案之一，他的核心参数是基音周期，分析过程采用ABS方法，提高了语音参数提取的准确性，可在噪声环境中合成出自然度和可懂度很高的语音。针对其基音搜索算法计算量过大的缺点，首先提出了一种新颖的中心偏离函数计算法，该方法先对原始语音进行傅里叶变换得到原始语音谱，再针对各个基音候选值确定其相应于原始语音谱的予带划分，通过对比每个划分的中心偏离量，可以确定最佳基音周期；其次设计了一种简单有效的倍频消除算法，通过简单的循环计算，可以消除倍频现象；仿真结果表明，这两种方法的结合不仅大大降低了原算法的计算量，而且保持了他精度高的优点。     

Algorithm for Scheduling Variable-Length Messages in WDM Networks

In this paper, we develop and analyze a simple algorithm for scheduling variable length messages in WDM networks with a passive star coupler. We base our schemes on a star topology with centralized control and use a scheduling algorithm similar to the process management in UNIX system. Every node and message have a scheduling priority associated with them. By comparing our algorithm with random select algorithm, we find that significant improvement in performance can be achieved with very little extra cost.     

Flexible, highly scalable, object-based wavelet image compression algorithm for network applications

The authors propose a highly scalable image compression scheme based on the set partitioning in hierarchical trees (SPIHT) algorithm. The proposed algorithm, called highly scalable SPIHT (HS-SPIHT), adds the spatial scalability feature to the SPIHT algorithm through the introduction of multiple resolution-dependent lists and a resolution-dependent sorting pass. It keeps the important features of the original SPIHT algorithm such as compression efficiency, full SNR scalability and low complexity. The flexible bitstream of the HS-SPIHT encoder can easily be adapted to various resolution requirements at any bit rate. The parsing process can be carried out on-the-fly without decoding the bitstream by a simple parser (transcoder) that forms a part of a smart network. The HS-SPIHT algorithm is further developed for fully scalable coding of arbitrarily shaped visual objects. The proposed highly scalable algorithm finds applications in progressive web browsing, visual databases and especially in image transmission over heterogeneous networks.     

A SCHEDULING ALGORITHM USING COMPENSATING ROUND ROBIN IN PACKET—SWTICHING BROADBAND NETWORKS

A new approximation of fair queuing called Comensating Round Robin(CRR)ia presented in this paper.The algorithm uses packet-by-packet scheduler with a compensating measure.It achieves good fairness in terms of throrghput ,requires onlyO(1)time complexity to process a packet ,and is simple enough to be implemented in hardware.After the performances are analyzed ,the fairness and is simple enough to be implemented in hardware.After the performances are that the CRR can effectively isolate the effects of contending sources.     

Adaptive-Array Algorithm for Interference Suppression Prior to Acquisition of Direct-Sequence Signal

Strong directional interference can prevent code acquisition in a direct-sequence system, thereby rendering the system inoperable. This paper presents a computationally simple adaptive-array algorithm that cancels directional interference prior to code acquisition when the direction of arrival of the desired signal is unknown, no pilot symbols are available, and long spreading sequences must be accommodated. The preacquisition algorithm is shown to dramatically reduce the interference level relative to that of a desired direct-sequence signal before code acquisition has been achieved. As a result, the code acquisition process is greatly facilitated.     

Fast 2-D distance transformations

The performance of a number of image processing methods depends on the output quality of a distance transformation (DT) process. Most of the fast DT methodologies are not accurate, whereas other error-free DT algorithms are not very fast. In this paper, a novel, fast, simple, and error-free DT algorithm is presented. By recording the relative x- and y-coordinates of the examined image pixels, an optimal algorithm can be developed to achieve the DT of an image correctly and efficiently in constant time without any iteration. Furthermore, the proposed method is general since it can be used by any kind of distance function, leading to accurate image DTs.     

Direct evaluation of fault trees using object-oriented programmingtechniques

Object-oriented programming techniques are used in an algorithm for the direct evaluation of fault trees. The algorithm combines a simple bottom-up procedure for trees without repeated events with a top-down recursive procedure for trees with repeated events. The object-oriented approach results in a dynamic modularization of the tree at each step in the reduction process. The algorithm reduces the number of recursive calls required to solve trees with repeated events and calculates intermediate results as well as the solution of the top event. The intermediate results can be reused if part of the tree is modified. An example is presented in which the results of the algorithm implemented with conventional techniques are compared to those of the object-oriented approach     

一种改进的Ford算法

针对不含负回路网络中最短路Ford算法运算量大、直观性差的不足,引入表上作业法思想,从提高算法效率和增强计算直观性2个方面对其进行改进,并给出新的算法。新算法既能快速计算最短路权又能更直观地表现解题过程,是一种计算最短路的简捷方法。仿真结果和算例表明了新算法的有效性。     

基于原生熵的Logistic映射复杂性分析

在序列原生生成过程的基础上,提出了原生熵的概念来分析离散混沌映射的复杂性。先对实值混沌映射量化成二值混沌序列,然后计算其原生熵的大小,并以Logistic映射为例证明了此算法的有效性。仿真结果表明此方法能反映离散混沌系统的随机本质,可用于准确度量离散混沌系统的复杂性强弱,且计算简单。     

基于直方图均衡变换的彩色YUV图像边缘检测方法

本文对基于改进的YUV颜色空间的边缘检测算法进行了研究.结果表明,对不同颜色空间的优缺点、特征性进行对比,从而提出了以YUV颜色空间为基础的改进算法,对其边缘检测算法的基本原理进行了详细的分析阐述.结合多元化仿真实验手段的相互比对,最终确定试验结果的优劣性,再结合理论分析和实验效果图,最终确定基于增大YUV颜色空间中Y、U、V分量的差异,并针对其中存在的问题提出可行性的边缘信息有效方案.本文通过改进后提出了更为简单的方案,同时具有高效性优势.     

基于改进A*算法的水下航行器自主搜索航迹规划

以水下航行器在水下路径规划为研究重点,提出了基于改进型A*算法的水下无人航行器自主搜索航迹规划算法。一般航迹规划可由多种算法完成,而在这些算法中以A*的计算流程最为简单、算法易于实现,并在理论上可保证全局最优解的收敛性;且程序较为简短,可在一些低功耗、低主频的系统中应用。由于传统的A*算法不具备最小转弯半径等约束条件,因此,针对水下航行器高低速问题,对传统的A*算法进行改进,使得A*算法可实现高速与低速相结合的应用。     

播出应急可视化一键式切换优化算法

在电视节目的安全播出中,采用多路输入互为备份的方式,可以有效地避免因单点故障而导致整个频道的输出异常。特别是大型电视台,会采用主路、备路、备二、垫片四路输入,然而四路之间复杂的切换关系,使值班人员通常要花费较长时间判断,并且容易出错。通过可视化一键式切换优化算法,将原来复杂的人工判断交由计算机来完成,将原来需要组合判断的故障处理条件简为两画面之间的切换,并且明确给出“切”与“不切”的准确提示,加之可视化效果,使整个过程简单、明了、准确、快捷。最终通过程序验证,证实了算法在提高值班人员故障处理便捷性和准确性上有很好的效果。