介绍了在In ternet环境下的一种文档管理系统——基于W ebDAV协议的文档管理系统的设计及实现。该系统采用Java语言编制,可利用浏览器直接实现对各种文档的管理。同时介绍了分布式文档创作与版本管理W ebDAV(W eb d istribu ted au thor...介绍了在In ternet环境下的一种文档管理系统——基于W ebDAV协议的文档管理系统的设计及实现。该系统采用Java语言编制,可利用浏览器直接实现对各种文档的管理。同时介绍了分布式文档创作与版本管理W ebDAV(W eb d istribu ted au thoring and vers ion ing)协议,讨论了W ebDAV协议提供的一个多层的和易于扩展的文档管理系统的体系结构。展开更多
It is an important issue to study sea clutter suppression because it could interfere with the detection of targets above the sea surface severely. Spatial spectrum analyses show that the majority of sea clutter has lo...It is an important issue to study sea clutter suppression because it could interfere with the detection of targets above the sea surface severely. Spatial spectrum analyses show that the majority of sea clutter has low-frequency characteristics, compared to the high-frequency characteristics of the targets. This paper proposes a frequency-based spatial tracking filter to suppress sea clutter to facilitate targets identification. Experimental results show that the signal-to-clutter ratio can increase by more than 10 dB after filtering and the algorithm is feasible for practical use. In addition, the filtering equation can be optimized to maximize the signal-to-clutter ratio improvement. The equation parameters can also be adjusted to give a proper cut-off frequency for different targets and clutter.展开更多
文摘介绍了在In ternet环境下的一种文档管理系统——基于W ebDAV协议的文档管理系统的设计及实现。该系统采用Java语言编制,可利用浏览器直接实现对各种文档的管理。同时介绍了分布式文档创作与版本管理W ebDAV(W eb d istribu ted au thoring and vers ion ing)协议,讨论了W ebDAV协议提供的一个多层的和易于扩展的文档管理系统的体系结构。
文摘It is an important issue to study sea clutter suppression because it could interfere with the detection of targets above the sea surface severely. Spatial spectrum analyses show that the majority of sea clutter has low-frequency characteristics, compared to the high-frequency characteristics of the targets. This paper proposes a frequency-based spatial tracking filter to suppress sea clutter to facilitate targets identification. Experimental results show that the signal-to-clutter ratio can increase by more than 10 dB after filtering and the algorithm is feasible for practical use. In addition, the filtering equation can be optimized to maximize the signal-to-clutter ratio improvement. The equation parameters can also be adjusted to give a proper cut-off frequency for different targets and clutter.
