首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
New families of Fisher information and entropy power inequalities for sums of independent random variables are presented. These inequalities relate the information in the sum of n independent random variables to the information contained in sums over subsets of the random variables, for an arbitrary collection of subsets. As a consequence, a simple proof of the monotonicity of information in central limit theorems is obtained, both in the setting of independent and identically distributed (i.i.d.) summands as well as in the more general setting of independent summands with variance-standardized sums.  相似文献   

2.
Expressions for (entropy-power inequality (EPI) Shannon type) divergence-power inequalities (DPIs) in two cases (time-discrete and time-continuous) of stationary random processes are given. The new expressions connect the divergence rate of the sum of independent processes, the individual divergence rate of each process, and their power spectral densities. All divergences are between a process and a Gaussian process with same second-order statistics, and are assumed to be finite. A new proof of the Shannon EPI, based on the relationship between divergence and causal minimum mean-square error (CMMSE) in Gaussian channels with large signal-to-noise ratio, is also shown  相似文献   

3.
基于最优分类系数及分类熵准则的模糊C均值聚类算法   总被引:1,自引:0,他引:1  
本文分别以模糊分类系数和分类熵为聚类有效性的测度函数,采用模糊C均值分类法,求最优的测度函数值所代表的全局极值的那种分类,确定为最佳分类方,对一张由卫星拍摄的地面MIG-29型飞机照片进行了成功的分类试验。  相似文献   

4.
It has been recently discovered that complementary graph entropy characterizes (and offers new insights into) the minimum asymptotic rate for zero-error source coding with decoder side information. This paper presents new results that build on and complement this discovery. Specifically, i) previously unknown subadditivity properties of complementary graph entropy are derived, and ii) zero-error coding rates are characterized in terms of complementary graph entropy for two multiterminal coding scenarios. For both scenarios, the rate characterization implies no rate loss relative to point-to-point source coding.   相似文献   

5.
Entropy rate is a real valued functional on the space of discrete random sources for which it exists. However, it lacks existence proofs and/or closed formulas even for classes of random sources which have intuitive parameterizations. A good way to overcome this problem is to examine its analytic properties relative to some reasonable topology. A canonical choice of a topology is that of the norm of total variation as it immediately arises with the idea of a discrete random source as a probability measure on sequence space. It is shown that both upper and lower entropy rate, hence entropy rate itself if it exists, are Lipschitzian relative to this topology, which, by well known facts, is close to differentiability. An application of this theorem leads to a simple and elementary proof of the existence of entropy rate of random sources with finite evolution dimension. This class of sources encompasses arbitrary hidden Markov sources and quantum random walks.  相似文献   

6.
We study the entropy rate of pattern sequences of stochastic processes, and its relationship to the entropy rate of the original process. We give a complete characterization of this relationship for independent and identically distributed (i.i.d.) processes over arbitrary alphabets, stationary ergodic processes over discrete alphabets, and a broad family of stationary ergodic processes over uncountable alphabets. For cases where the entropy rate of the pattern process is infinite, we characterize the possible growth rate of the block entropy  相似文献   

7.
测试数据编码压缩是一类重要、经典的测试源划分(TRP)方法。本文提出了一种广义交替码,将FDR码、交替码都看作它的特例;又扩展了两步压缩方法,将原测试集划分成多组,每组采用不同的比值进行交替编码,综合了交替码与两步编码各自的优势,弥补了FDR码,交替码对某些电路测试集压缩的缺陷,得到了较好的压缩率。实验结果表明,与同类型的编码压缩方法相比,该方案具有更高的测试数据压缩率和较好的综合测试性能。  相似文献   

8.
谈分割振动   总被引:1,自引:1,他引:0  
1引言振膜分割振动是一个老大难问题,至今未能找到有效解决方法。分析振膜分割振动的表现形式,有两种形态,一种是放射状形态,发生在低频段,从百赫兹到2kHz附近。另一种是环状的分割振动,发生在中频和高频频段。传统理论认为放射状分割振动与振膜的不均匀性有关,而环状分割振动产生原因在于折环的反共振,并与振膜自身的共振有关。根据这一思路,改进环状分割振动就应从折环着手,主要是改进折环的顺性和阻尼,使其对锥盆振动的反射减弱,其次是增加振膜自身的阻尼特性,减弱反射波的影响。但笔者发现,尽管人们对折环和振膜作了大…  相似文献   

9.
With the aim to reduce disorder and improve efficiency, nodes in an ad hoc network run a self-organization scheme to cooperatively organize the network. Although metrics such as complexity or self-stability are commonly used for evaluation, to the best of our knowledge, none of them quantifies the efficiency to build and maintain an organization (order). We henceforth apply the notion of entropy to ad hoc type wireless networks facilitating a quantification of the internal organizational state generated by different self-organization schemes. Invoking node and link failure probabilities, we expose the dependency of the organizational state on the self-organization protocol of choice.  相似文献   

10.
胡尚坤  孙雨泽  杨小鹏  曾涛  龙腾 《信号处理》2017,33(8):1132-1137
为了降低硬件成本和系统的复杂度,子阵划分对于大型的相控阵雷达来说是必要的。传统的子阵划分方法主要针对信号处理的单一性能指标优化。针对多项指标优化的问题,本文提出了一种基于粒子群算法的子阵划分结构优化算法,相对于传统的方法能够同时优化多项性能指标,提高信号处理的性能。通过对线性阵列的划分做仿真,展示了粒子群算法对子阵级波束形成多项性能指标的提高。   相似文献   

11.
纸币扎把的识别是纸币处理一个关键环节.目前识别纸币扎把的方法有图像颜色识别法和图像噪声边沿法,两种方法都需要保证扎把颜色与背景色有较大的差异,而且计算复杂.提出了图像分块的图像熵计算方式来完成纸币捆中的扎把区域识别的新思路,放宽了条件,提高了识别速度.  相似文献   

12.
Some entropy comparison results are presented concerning compound distributions on nonnegative integers. The main result shows that, under a log-concavity assumption, two compound distributions are ordered in terms of Shannon entropy if both the ldquonumbers of claimsrdquo and the ldquoclaim sizesrdquo are ordered accordingly in the convex order. Several maximum/minimum entropy theorems follow as a consequence. Most importantly, two recent results of Johnson (2008) on maximum entropy characterizations of compound Poisson and compound binomial distributions are proved under fewer assumptions and with simpler arguments.  相似文献   

13.
Defining DVD     
《Multimedia, IEEE》1999,6(1):80-84
The accepted and much-repeated definition for DVD is digital versatile disc or digital video disc, depending on whom you ask. The words behind the letters are not the only things about DVD whose meaning depends on the respondent; you will also get a different answer regarding DVD's purpose and future depending on individual viewpoint. The author gives a brief history of DVD and considers DVD-ROM and DVD Video  相似文献   

14.
Multimedia is variously and often ambiguously defined. While most people might accept a mix of voice, text and graphics, they might resist calling a live lecture on a titled work of art a multimedia presentation. On the other hand, many definitions focus entirely on technology: multimedia seems to be defined by the hardware required rather than by the user's experience. For example, despite the statement that any computer application that employs a video disk, images from a CD-ROM, uses high-quality sound, or uses high-quality video images on a screen may be termed a multimedia application, the author doubts that anyone would use the term multimedia for a computer application that merely plays a piece of music. She suggests a model of media objects that does not refer to technology or interactivity, but rather concentrates on the nature of the text. This model provides a useful basis for defining multimedia communication securely and unambiguously  相似文献   

15.
现有基于网络报文流量信息的协议分析方法仅考虑报文载荷中的明文信息,不适用于包含大量密文信息的安全协议。为充分发掘利用未知规范安全协议的密文数据特征,针对安全协议报文明密文混合、密文位置可变的特点,该文提出一种基于熵估计的安全协议密文域识别方法CFIA(Ciphertext Field Identification Approach)。在挖掘关键词序列的基础上,利用字节样本熵描述网络流中字节的分布特性,并依据密文的随机性特征,基于熵估计预定位密文域分布区间,进而查找密文长度域,定位密文域边界,识别密文域。实验结果表明,该方法仅依靠网络数据流量信息即可有效识别协议密文域,并具有较高的准确率。  相似文献   

16.
针对基于深度图的视点绘制中空洞填补时产生的图像失真问题,提出一种还原空洞区域可靠纹理的空洞填补方法。通过从临近的帧画面中提取有效信息还原真实的背景图像,用于新视点中背景区域的空洞填补。并通过区分前景和背景图像区域,对不同区域的空洞采取不同的填充方法,从而获得较为可靠和真实的填补效果。从实验结果来看,该方法获得的PSNR数据优于其他算法,并且与真实视点比较的结构相似度达到99.1%,比传统方法提高10%以上。  相似文献   

17.
一种改进的基于熵的图像检索算法   总被引:5,自引:4,他引:1  
利用信息熵可以有效的将图像颜色直方图特征降低到一维,但以往的基于信息熵的图像检索算法却没有考虑熵的对称特性,因此极易造成误检现象.基于此,文中提出了相应的改进算法,消除由于熵的对称性对图像检索效果造成的影响.试验结果证明改进的方法在进行图像检索时具有更强的鲁棒性,大大提高了图像检索效率.  相似文献   

18.
AVS熵解码与DSP实现   总被引:3,自引:0,他引:3  
阐述了AVS标准的进展情况及AVS标准的特点,重点介绍了AVS熵解码的原理和采用Equator公司MAP-CABSP-15处理器中的协处理器(Vlx)实现AVS熵解码的方法.  相似文献   

19.
Estimation of the differential entropy from observations of a random variable is of great importance for a wide range of signal processing applications such as source coding, pattern recognition, hypothesis testing, and blind source separation. In this paper, we present a method for estimation of the Shannon differential entropy that accounts for embedded manifolds. The method is based on high-rate quantization theory and forms an extension of the classical nearest-neighbor entropy estimator. The estimator is consistent in the mean square sense and an upper bound on the rate of convergence of the estimator is given. Because of the close connection between compression and Shannon entropy, the proposed method has an advantage over methods estimating the Renyi entropy. Through experiments on uniformly distributed data on known manifolds and real-world speech data we show the accuracy and usefulness of our proposed method.  相似文献   

20.
By the means of computing approximate entropy (ApEn) of video-EEG from some clinical epileptic, ApEn of EEG with epileptiform discharges is found significantly different from that of EEG without epileptiforrn discharges, (p=0.002). Meanwhile, dynamic ApEn shows consistent change of EEG signal with discharges of epileptic waves inside. These results suggest that ApEn may be a useful tool for automatic recognition and detection of epileptic activity and for understanding epileptogenic mechanism.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号