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61.
Lei Guo Xingwei Wang Qingyang Song Weigang Hou Fei Yang 《Information Sciences》2008,178(18):3635-3644
With the development of intelligent optical networks and the general multi-protocol label switching (GMPLS) technique, the seamless convergence between IP network and optical network is no longer be a dream but a practical reality. Similar to the Internet, current optical networks have been divided into multiple domains each of which has its own network provider and management policy. Therefore, the development of multi-domain optical networks will be the trend of new-generation intelligent optical networks, and GMPLS-based survivability for multi-domain optical networks will become a hot topic of research in the future. This paper provides a comprehensive review of the existing survivable schemes in multi-domain optical networks and analyzes the shortcomings of current research. Based on previous studies, we present possible challenges and propose new ideas to design efficient survivable schemes to guide the future work of researchers in multi-domain optical networks. 相似文献
62.
Tal Nir Alfred M. Bruckstein Ron Kimmel 《International Journal of Computer Vision》2008,76(2):205-216
A novel optical flow estimation process based on a spatio-temporal model with varying coefficients multiplying a set of basis
functions at each pixel is introduced. Previous optical flow estimation methodologies did not use such an over parameterized
representation of the flow field as the problem is ill-posed even without introducing any additional parameters: Neighborhood
based methods of the Lucas–Kanade type determine the flow at each pixel by constraining the flow to be described by a few
parameters in small neighborhoods. Modern variational methods represent the optic flow directly via the flow field components
at each pixel. The benefit of over-parametrization becomes evident in the smoothness term, which instead of directly penalizing
for changes in the optic flow, accumulates a cost of deviating from the assumed optic flow model. Our proposed method is very
general and the classical variational optical flow techniques are special cases of it, when used in conjunction with constant
basis functions. Experimental results with the novel flow estimation process yield significant improvements with respect to
the best results published so far. 相似文献
63.
Redox and acid–base properties of thionine immobilized in crosslinked chitosan films are analyzed. The experimental conditions for the preparation of the films are described. Results obtained with cyclic voltammetry, spectroelectrochemistry and spectrophotometry indicate that the immobilized dye retains the redox and acid–base activity of free thionine. An acid dissociation constant (Ka) for the immobilized dye of Ka = 2.7 × 10−11 was obtained.
Due to the stable and reversible pH dependent optical signal of the studied film, this membrane can be used as a building component of an optical pH sensor. 相似文献
64.
一些传统计算方法对非线性系统的分析存在着一些困难。针对光反馈半导体激光器收发系统微分方程组的特点,对非线性性质做出了数学上的分析,考虑到在光反馈半导体激光器收发系统中,其微分方程含有延迟因子,无法直接利用多节点上的值的加权和来近似计算斜率。基于龙格-库塔法提出了一种有效的数值仿真算法,并在matlab平台上对给定参数条件下的发射端与接收端的归一化光场以及同步误差进行了仿真,证明了接收端光场信号可以很快与发射端光场信号一致,仿真结果表明仿真算法能有效对系统进行仿真分析。 相似文献
65.
基于二重差分法的光流场运动检测 总被引:2,自引:1,他引:1
对视频图像序列中运动目标的检测,是计算机视觉领域长期关注的问题.传统的Horn-Schunck光流算法非常耗时,不利于在视频图像序列中做实时分析,故提出采用结合背景差分法与帧间差分法的二重差分法(DS)来做光流算法的预处理.实验结果也表明二重差分法的光流算法(DSOF)比单纯用Horn-Schunck方法计算光流效率更高,用时更短,能更好地满足对视频图像序列做实时运动检测分析的需求. 相似文献
66.
考虑脉冲位置调制(PPM)在解调时需要严格的时钟同步和符号同步,而且功率越高,时隙越窄的问题,结合差分脉冲位置调制(DPPM)和脉冲宽度调制(PWM)提出了一种有效的调制方式--差分脉冲位置宽度调制(DPPM+PWM).研究了采用DPPM+PWM的红外通信系统在加性高斯白噪声干扰下的性能,对DPPM+PWM的符号结构、发射功率、带宽需求、传输容量以及误包率等特性进行了分析,并通过仿真与开关键控(OOK),PPM,PPM等调制方式进行了比较.结果表明DP-PM+PWM频带利用率高,传输容量大,不需要符号同步,且增加了脉冲信号的长度,大大简化系统实现,是一种很有实际应用价值的调制方式. 相似文献
67.
68.
In this paper, we review the state-of-the-art in surface-enhanced Raman scattering (SERS) based optical detection techniques
with an application focus on cancer diagnostics. As we describe herein, SERS has several analytical, biological and engineering
advantages over other methods including extremely high sensitivity, inherent molecular specificity of unlabeled targets, and
narrow spectral bands. We review advances in both in vitro and in vivo applications of SERS and examine how technical issues
with the technology are being addressed. A special technology focus is given to emerging optofluidic devices which aim to
merge microfluidic and optical detection technologies into simple packages. We conclude with a brief discussion of some of
the emerging challenges in the field and some of the approaches that are likely to enhance their application.
Y. S. Huh and A. J. Chung contributed equally. 相似文献
69.
以太无源先网络是一个专门应用于接入网的技术.采用点到多点的网络拓扑结构,在一芯光纤上利用上下行两个波传输数据,下行数据采用广播方式的时分复用方式,上行数据采用时分多址接入的方式,达到利用光纤实现数据、语音和视频多种业务接入的目的. 相似文献
70.
F. V. Konusov R. V. Sazonov D. V. Ponomarev I. S. Zhirkov 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(6):343-347
This paper presents the results of an experimental investigation on the optical properties of the TiO2 and TixCyOz nanopowders, produced by the pulsed plasma chemical method. Pulsed plasma chemical synthesis is realized on the laboratory stand, including a plasma chemical reactor (6 l) and TEA-500 electron accelerator. The parameters of the electron beam are as follows: 400–450 keV electron energy, 60 ns half-amplitude pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. In TiO2 sample, obtained using the pulsed plasma chemical method, the particles can be divided into two groups: 100–500 nm large spherical particles and tiny complex particles (sized less than 100 nm). For TixCyOz sample, the morphology of the particles is mainly presented with irregular fragment shape. The average size of the particles is ranged from 200 to 300 nm. The band gap for all synthesized samples is within 2.94–3.35 eV. 相似文献