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141.
讲述了基于离散余弦变换(DCT)的JPEG标准和基于离散小波变换(DWT)的JPEG-2000标准的各自特点,比较指出后者的优越性,并着重介绍新一代静态图像压缩标准JPEG-2000。 相似文献
142.
143.
We show, for two different definitions of semiglobal practical external stability, that the stability property holds on semi-infinite
time intervals if and only if it holds on arbitrarily long but finite time intervals. These results have immediate applications
in the analysis of the stability properties of highly oscillatory systems with inputs using averaging or for systems with
inputs that are slowly varying. Results are stated for general flows and the stability is given with respect to arbitrary
(not necessarily compact) sets.
Date received: May 11, 2001. Date revised: March 14, 2002. 相似文献
144.
Kuo-Lung WuAuthor VitaeMiin-Shen YangAuthor Vitae 《Pattern recognition》2002,35(10):2267-2278
In this paper we propose a new metric to replace the Euclidean norm in c-means clustering procedures. On the basis of the robust statistic and the influence function, we claim that the proposed new metric is more robust than the Euclidean norm. We then create two new clustering methods called the alternative hard c-means (AHCM) and alternative fuzzy c-means (AFCM) clustering algorithms. These alternative types of c-means clustering have more robustness than c-means clustering. Numerical results show that AHCM has better performance than HCM and AFCM is better than FCM. We recommend AFCM for use in cluster analysis. Recently, this AFCM algorithm has successfully been used in segmenting the magnetic resonance image of Ophthalmology to differentiate the abnormal tissues from the normal tissues. 相似文献
145.
Robust and efficient content-based digital audio watermarking 总被引:2,自引:0,他引:2
This paper proposes a set of digital watermarking schemes for WAV audio, WAV-table synthesis audio and compressed audio.
The watermark embedding scheme is closely related to audio content and based on the human auditory system. The experimental
results in listening and robustness illustrate that the proposed watermarking schemes can achieve an optimal balance between
audibility and robustness of the watermarked audio. The proposed methods are also very useful and effective for copyright
protection, tracing illegal distribution and other applications. 相似文献
146.
Hartmut Logemann Richard Rebarber 《Mathematics of Control, Signals, and Systems (MCSS)》1996,9(2):123-151
It has been observed that for many stable feedback systems, the introduction of arbitrarily small time-delays into the loop causes instability. In this paper we present a systematic treatment of this phenomenon for a large class of boundary control systems which allows for in-span control. Our approach is based on a combination of input-output methods and modal analysis. We give a number of sufficient conditions for robustness/nonrobustness of closed-loop input-output stability with respect to delays. Our framework includes a large class of ill-posed systems, i.e., systems whose open-loop transfer function is unbounded on any right half-plane. We then analyze the relationship between the poles of the transfer function and the exponential modes of the underlying boundary-value problem to derive internal stability properties from external ones.This work was supported by the British Council/DAAD (ARC project 464), by the Human Capital and Mobility programme (Project number CHRX-CT93-0402), by the National Science Foundation (Grant DMS-9206986) and by NATO (Grant CRG 950179). 相似文献
147.
The purpose of this note is to give a counterexample to a possible implication of the main result of the above paper [1]. 相似文献
148.
A multivariable analog system can be controlled by a sampled-data compensator. A conic sector that can be used to analyze the closed-loop stability and robustness of this feedback system is presented in this letter. 相似文献
149.
Redundancy and robustness of systems of events 总被引:5,自引:0,他引:5
K.
iha 《Probabilistic Engineering Mechanics》2000,15(4):347-357
The article aims to add a new impetus to rational and objective probabilistic evaluation of redundancy and robustness, based on uncertainties of systems and subsystems of events. An attempt is made to demonstrate the relevance of intuitive comprehension of redundancy and robustness of engineering systems of events. An event-oriented system analysis of a number of random observable operational and failure modes, with adverse probability distributions in a lifetime, may provide a deeper understanding of systems operational abundance and endurance. The system uncertainty analysis is based on the concept of entropy as defined in information theory and applied to probability theory. The article relates reliability, uncertainty, redundancy and robustness of systems of events and their application is illustrated in numerical examples. 相似文献
150.