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131.
采用25.344 Mbit/s光监控信息传送技术可以更好地满足当前密集波分复用(DWDM)系统中不断增加的网络监控信息和附加业务的需要.文章首先介绍了25.344 Mbit/s光监控信息传送系统的技术方案,然后详细描述了其帧结构、码型设计以及硬件实现的框图,最后介绍了该技术的优点. 相似文献
132.
133.
Shear Stress in Smooth Rectangular Open-Channel Flows 总被引:1,自引:0,他引:1
The average bed and sidewall shear stresses in smooth rectangular open-channel flows are determined after solving the continuity and momentum equations. The analysis shows that the shear stresses are function of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress. An analytical solution in terms of series expansion is obtained for the case of constant eddy viscosity without secondary currents. In comparison with laboratory measurements, it slightly overestimates the average bed shear stress measurements but underestimates the average sidewall shear stress by 17% when the width–depth ratio becomes large. A second approximation is formulated after introducing two empirical correction factors. The second approximation agrees very well (R2>0.99 and average relative error less than 6%) with experimental measurements over a wide range of width–depth ratios. 相似文献
134.
In this paper, experimental data collected in a straight flume having a bed covered by grasslike vegetation have been used to analyze flow resistance for flexible submerged elements. At first, the measurements are used to test the applicability of Kouwen’s method. Then, a calibration of two coefficients appearing in the semilogarithmic flow resistance equation is carried out. Finally, applying the Π-theorem and the incomplete self-similarity condition, a flow resistance equation linking the friction factor with the shear Reynolds number, the depth-vegetation height ratio and the inflection degree is deduced. 相似文献
135.
Nobuhiko Tamura Norimichi Tsumura Yoichi Miyake 《Journal of the Society for Information Display》2003,11(2):333-339
Abstract— A color management system (CMS) such as ICC profile or sRGB space have been proposed for color transformation and reproduction of cross media. In such a CMS, accurate colorimetric characterization of a display device plays a critical role in achieving device‐independent color reproduction. In the case of a CRT, colorimetric characterization based on a GOG model is accurate enough for this purpose. However, there is no effective counterpart in liquid‐crystal displays (LCDs) since the characterization of an LCD has many difficulties, such as channel interaction and non‐constancy of channel chromaticity. In this paper, a new method of display characterization is proposed which is applicable to the assessment of color reproduction of LCDs. The proposed method characterizes an electro‐optical transfer function considering both channel interaction and non‐constancy of channel chromaticity. Experimental results show that the proposed method is very effective in the colorimetry of LCDs. 相似文献
136.
对同一目标的多波谱遥感图像进行融合、是富集有用信息、提高图像空间分辨率和解释水平的有效手段,本文提出了基于小波多分辨率分析的多通道遥感图像数据融合的原理、方法及实现过程,实例分析其结果良好。 相似文献
137.
Hsin-Lu Chang Robert F. Easley Michael J. Shaw 《Information Systems and E-Business Management》2003,1(2):213-228
This research seeks to provide an economic framework for understanding two major forms of e-marketplaces: aggregation-oriented
vs. exchange-oriented e-marketplaces. By analyzing the marginal benefit per transaction in alternative models, we are able
to determine the most suitable B2B e-marketplace for a wide variety of product categories, market conditions, and procurement
methods. For example, when companies sell commodities in a fragmented market, the aggregation model is suitable for spot purchasing,
and the exchange model works best for systematic purchasing. In addition, the effect of supplier consolidation and information
technology-enabled cost reduction on model selection is discussed. 相似文献
138.
139.
对企业电力线载波通信质量较差的原因进行了分析,认为噪音的产生与电力线上各类用电负载的开闭及大功率电机的转速有关,并提出了相应的解决方法。 相似文献
140.