排序方式： 共有7条查询结果，搜索用时 15 毫秒
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当前信号远程传输方法,没有实现传输通道能量与传输通道信号并行,导致信号远程传输失真性较高。为提高地震信号远程传输的效率,提出新的高速铁路地震监测系统中信号远程传输技术。采用信号传输通道中地震信号能量的并行方法,通过信号传输通道中信号并行传输结构,实现信号在传输通道中双向传输;利用高频阻波电路阻断信号的高频载波通过谐振补偿电容,确保传输通道能量传输不受干扰;根据通道能量传输结构与信号传输过程,实现传输通道能量、信号并行,完成高速铁路地震信号远程传输中的失真控制。实验结果表明,所提方法丢包率较低,均值约为3%,远程传输时延仅为0.9s,是一种低误差、高效率的高速铁路地震信号远程传输方法。 相似文献
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阐述了虚拟仪器开发平台Lab VIEW的开发环境，并用图形化编程语言Lab VIEW设计了虚拟气象统计分析仪，分析仪界面友好、直观，适合于气象统计中数据的分析与处理。将虚拟仪器技术引入到气象科研中，使用在Lab VIEW平台下开发的控件，根据研究需要“组装”各种仪器，能够较大地提高工作效率。 相似文献
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《制图学和地理信息科学》2013,40(2):91-100
Approximately half of the planetary bodies in our solar system imaged by spacecraft have irregular shapes. Since maps are used to record, interpret and display these irregularly shaped bodies, a special map projection, which can display them faithfully, is desirable. Unfortunately, no mathematical approach that permits true conformal or equal-area projections has been developed. In this paper, a novel approach to construct a special equal area map projection for irregularly shaped objects is suggested. Using this innovative approach, equal area map projections for two Martian satellites—Phobos and Deimos are—developed. 相似文献
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Rosa Freitas Leandro Sampaio Ana Maria Rodrigues Victor Quintino 《Estuarine, Coastal and Shelf Science》2005,65(4):625-632
An acoustic ground discrimination system (QTC VIEW, Series IV) was used to identify and map the bottom acoustic diversity in the bar channel of Ria de Aveiro, Western Portugal. The majority of the survey area presented shallow depth for this type of equipment, ranging mainly from 5 to 15 m. Depth occasionally reached 25 m in specific areas located across the entrance channel, dug by the strong tidal currents, reaching 3 m/s. The acoustic data were submitted to manual and auto-cluster and the results obtained from both procedures were coherent. Using aids to the acoustic classification and ground-truth sediment data, a final solution consisting of four acoustic classes was reached. Their geographical distribution was coincident with the spatial distribution of the major bottom types and sediment groups (hard bottom, coarse sand, medium sand and fine sand), identified through multivariate analysis of the grain-size data, and reflected the complex hydrodynamics of the entrance channel. The acoustic pattern was coincident at the intersections of the acoustic survey lines, assuring the repeatability of the acoustic procedure. Overall, the acoustic approach showed consistent results for the assessment and mapping of the benthic habitats in this shallow-water coastal area, providing a very valuable tool in an area where conventional sediment sampling is less favourable, namely due to strong tidal currents and frequent ship traffic, such as the entrance channel of Ria de Aveiro and the near-shore adjacent shelf. 相似文献
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Rosa Freitas Ana Maria Rodrigues Edward Morris Jose Lucas Perez-Llorens Victor Quintino 《Estuarine, Coastal and Shelf Science》2008,78(4):613-622
The single-beam acoustic ground discrimination system QTC View, Series V, was used in the Bay of Cadiz, Southwest Spain, for the identification and mapping of the bottom acoustic diversity. The acoustic data were obtained through two successive surveys, each conducted with one of the following echo sounder frequencies: 50 kHz and 200 kHz. The performance of each survey frequency for the identification of the sedimentary gradients was analyzed. The surveys were conducted during high tide given that the majority of the surveyed area is shallower than 5 m, although depth may occasionally reach 20 m in specific areas located in a navigation channel. The acoustic data obtained at the two different frequencies were, individually, submitted to manual clustering and a final solution consisting of three acoustic classes was reached for both datasets. However, only the geographical distribution of the acoustic classes obtained with 50 kHz echo sounder frequency was coincident with the spatial distribution of the superficial sediment groups (silty medium sand, very silty fine sand and mud), identified through multivariate analysis of the grain-size data of ground-truth sediment samples. The results obtained with the 200 kHz echo sounder frequency did not match the sedimentary gradients obtained for the area surveyed, not even the separation of muddy and sandy areas. 相似文献
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Transition zones (or ‘ecotones’) are ecologically important spatial elements of subtidal landscapes that represent a mixture of different habitat elements. We provide a method for identifying such areas in broad-scale surveys of the seafloor using the acoustic discrimination system QTC VIEW. QTC VIEW is an acoustic processing system that assigns sonar ping stacks to clusters of like points, to identify different habitats on the seafloor. Paired QTC VIEW transects (20 m spacing) were run at intervals of 200 m, at two separate sampling locations, to assess the consistency of clustering of individual ping stacks into acoustic classes. Very consistent spatial patterns of class change were found between transect pairs, suggesting high stability in the classification process. QTC VIEW assigns confidence values to each individual record; running averages calculated using a moving window along transects showed drops in confidence values associated with areas of transition in habitat class assignment, but this was not always consistent. The Berger–Parker index, a class dominance statistic, provided a more consistent transition indicator. Class transition ranged from abrupt to gradual, along with areas where a mixture of acoustic classes occurred. However, acoustically detected transition zones did not consistently respond to visual observations of the sea floor. 相似文献
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