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91.
温度是育肥棚的重要参数之一,过高或过低的温度都会影响牛羊的健康和食量,从而影响牛羊的育肥速度;针对此问题,从特有的地理环境和育肥棚的具体要求出发,设计了温度监控的硬软件系统。硬件由S3C2410处理器、DS18B20温度传感器、TC35模块以及一些外围电路组成;软件用C实现了通过手机短信来完成报警功能。测试结果表明:系统运行稳定可靠,能满足育肥棚温度的监控要求。 相似文献
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平行封焊是微电子器件封装过程中的最后一道工序,封焊质量的好坏对产品的合格率有很大的影响,为了提高焊接质量,进而提高平行封焊设备的性能,研究平行封焊工艺显得至关重要。 相似文献
94.
激光诱导击穿光谱技术在燃煤电厂及土壤污染物在线检测中的应用研究 总被引:2,自引:0,他引:2
介绍了自主研发的激光诱导击穿光强技术(LIBS)煤质在线检测设备,可完成自动取样并带有自清洁系统,能实时对电厂输煤管道中煤粉的C、Ca、Mg、Ti、Si、H、Al、Fe、S等元素进行自动定量分析并转化为工业分析(发热量和灰分)结果。提出了飞灰含碳量在线检测成套方案并研制了自动采样及LIBS检测装置,建立了去除C线中Fe线的数学方法,利用二阶多元非线性逆回归模型建立了定标方程来校正基底效应,获得了0.26%的C元素测量精度。开发了便携式LIBS设备用于土壤污染物的现场检测,可对土壤中的重金属污染物进行快速的定性分析。 相似文献
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《电子学报:英文版》2016,(4):641-647
It gets more and more important for video copyright protection, it is necessary to provide e?cient H.264 compression domain watermarking for video Digital rights management(DRM). A new watermarking method based on H.264 compressed domain is proposed for video DRM, in which the embedding and extracting procedure are performed using the syntactic elements of the com-pressed bit stream. In this way, complete decoding is un-necessary in both embedding and extracting processes. Based on the analysis of the time and space, some appro-priate sub-blocks are selected for embedding watermarks, increasing watermark robustness while reducing the dec-lination of the visual quality. In order to avoid bit-rate increasing and strengthen the security of the proposed video watermarking scheme, only a set of nonzero coe?-cients quantized in different parts of macroblocks is chosen for inserting watermark. The experiment results show the proposed scheme can achieve excellent robustness against some common attacks, the proposed scheme is secure and e?cient for video content DRM protection. 相似文献
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本文采用基于电压-频率变换(V/F)的数字相敏检测技术应用于光学监控信号检测,得到的被检测信号的幅度,即光学监控信号波形.而且针对光学监控系统中被检测信号特点,从理论分析角度说明了本方案抑制被检测信号低次谐波和白噪声的性能.仿真分析中针对加入了2,3,4次谐波和零均值随机白噪声,信噪比为20dB,频率为166Hz的被检测信号,利用本方案检测出光学监控信号反射率最大误差<0.2%.分别利用本方案检测出的光学监控信号和理想监控信号读取反射率极值点对应薄膜厚度,对比可知采用本方案监控膜厚理论误差<2nm. 相似文献
99.
Currently, most video on-demand services offered over the Internet do not exploit the idle resources available from end-users. We discuss the benefits of user-assistance in video on-demand systems, where users are both clients and servers, helping with the task of video distribution. The mathematical machinery for the systematic analysis of video on-demand services is not mature yet. In this paper we develop a deterministic fluid model to determine the expected evolution of user-assisted on-demand video streaming services. We theoretically prove that cooperative systems always outperform non-cooperative solutions. A combinatorial optimization problem is proposed, where the goal is to distribute a set of video items into repositories trying to offer the minimum waiting times to end-users. This combinatorial problem is proved to be in the class of NP-Complete computational problem, and is heuristically solved with a GRASP methodology. Predictions inspired in YouTube scenarios suggest the introduction of cooperation is both robust and extremely attractive from an economical viewpoint as well. 相似文献
100.
《Journal of Visual Communication and Image Representation》2014,25(3):542-554
In this paper, we study the impact of quantization, frame dropping and spatial down-sampling on the perceived quality of compressed video streams. Based on the analysis of quality ratings obtained from extensive subjective tests, we propose a no-reference metric (named MDVQM) for video quality estimation in the presence of both spatial and temporal quality impairments. The proposed metric is based on the per-pixel bitrate of the encoded stream and selected spatial and temporal activity measures extracted from the video content. All the values required to compute the proposed video quality metric can be obtained without using the original reference video which makes the metric for instance useful for making transcoding decisions in a wireless video transmission scenario. Different from comparable metrics in the literature, we have also considered the case when both frame rate and frame size are changed simultaneously. The validation results show that the proposed metric provides more accurate estimation of the video quality than the state of the art metrics. 相似文献