放顶煤采场顶板运动规律的研究

利用离散元和有限元数值模拟及力学解析计算，分析了放顶煤采场中上覆岩层运动规律；认为采场上覆岩层运动为分层运动，运动结构为拱－梁结构；拱－梁转换的实现，是以拱顶的失稳升高为条件，在分析了影响顶板运动的主要因素（顶板岩层断裂角、放煤步距、顶板岩层块体尺寸、顶煤厚度）的基础上，认为放煤步距过大（≥２ｍ）会降低放煤率，增大老顶垮落的动压冲击程度。放顶煤工作面与非放顶煤工作面的区别是，采空区充填系数小，顶板岩层运动剧烈，走向方向超前支承应力峰值较大。     

星箭包带锁紧装置分离过程动态包络的动力学仿真

包带锁紧装置是世界上各主要运载火箭大都采用的星箭连接和分离机构.随着卫星种类、结构形式的不断变化,卫星对包带装置提出了更高的要求.因此,对包带分离过程中动态包络的研究也显得日益重要.介绍了用ADAMS软件对包带装置分离过程动态包络进行动力学仿真的研究情况,包括建模的方法,模型的ADAMS描述,以及仿真结果与试验结果的比较.     

电网视频监控系统的智能分析应用研究

现有变电站视频监控系统大多局限于对站内设备整体全貌的视频监视,已实现的视频智能分析与监测功能比较少,无法满足智能变电站监测的要求。本文针对广东电网现有的变电站视频及环境监控系统存在的局限性,分析了当前对于视频智能分析应用的具体需求,并对相应的视频智能分析功能进行了研究及实施,从而进一步完善了现有广东电网变电站视频及环境监控系统的功能,提高了系统的实用性。     

Quantized based image watermarking in an independent domain

This paper presents a performance study for two well known quantized based watermarking schemes Scalar Costa Scheme (SCS), and Trellis Coded Quantization scheme (TCQ) in an independent domain. For our study, the independent domain is obtained by the combination of the cited schemes with Independent Component Analysis (ICA). The Independent Component Analysis is used while inserting and extracting the message. Thus a performance compromise improvement of the original SCS and TCQ schemes in terms of robustness, capacity, and security is shown. Then the obtained schemes performances are compared to the Spread Transform (ST) based scheme well known for its proven good robustness properties. Our results show that, using watermarking with side information in independent domain permits to improve the global SCS and TCQ schemes performances. For example, in the case of SCS, by studying the Bit Error Rate (BER) in function of the watermark to noise ratio (WNR), the robustness has been improved by 20 dB (1 decade) when WNR is equal to 0 dB. Moreover, the capacity study shows for the same WNR=0 dB, the amount of information to be transmitted without error for a given noise level of the proposed SCS combined with ICA scheme (SCS-ICA) is much higher than that of the existing schemes. Finally, the study of the probability density functions (PDF) of the original and marked signals has shown that the Cachin-security level of the TCQ in an independent domain scheme (TCQ-ICA) is the best one compared to the other known schemes.     

不同因素对动态热机械分析仪(DMA)测试结果的影响

通过对高Tg板材的动态热机械分析(DMA),研究了升温速率、样品厚度、有无覆金属层对测试结果的影响。文章旨在通过分析这些因素的影响机理,深入了解板材的粘弹性能,为PCB板材热性能测试提供参考借鉴。     

分析半导体工艺设备中可编程逻辑器件

本文介绍在半导体工艺设备中常见的可编程逻辑器件，以及分析电器板中的可编程逻辑器件，写出已加密GAL器件的逻辑功能。     

一种短信业务分布预测算法分析

随着移动通信短信业务的迅速发展,现有的短信业务分布预测算法已经无法满足需求。提出了一种基于聚类分析和模拟退火的短信业务分布预测算法。根据电子地图、基站语音和短信业务统计数据,提取影响短信业务分布的相关属性,采用聚类分析方法中的自组织映射(Self Organizing Map,SOM)方法和k-means算法,将网络中基站进行分类,然后采用模拟退火算法和最小二乘法计算得到不同类型基站中的不同地物的短信日均业务密度值,从而达到对短信进行业务分布预测的目的。通过实际基站短信业务统计数据的验证,该算法大幅提高了短信业务分布预测的准确度。     

主成分分析的图像压缩与重构

针对图像占用空间大,特征表示时维数较高等的缺点,系统介绍了主成分分析（PCA）的基本原理。提出了利用PCA进行图像数据压缩与重建的基本模型。实验结果表明,利用PCA能有效的减少数据的维数,进行特征提取,实现图像压缩,同时并根据实际需要重建图像。     

On the hybrid multi-watermarking

Multi-watermarking is the technique to embed multiple messages into the same media content repeatedly. It can be used to identify media content's ownership or trace the illegal redistributors in media distribution. However, some performances of multiple watermark embedding, e.g., the distortion and security, are not considered carefully in the previous work. In this paper, the application scenario and framework of hybrid multi-watermarking are figured out, which show the secure media distribution model suitable for hierarchical media distribution. Additionally, the multi-watermarking based on hybrid multiplicative rule is firstly proposed and then analyzed theoretically with respect to two cases, i.e., the multi-embedding of same watermark sequence and the multi-embedding of different watermark sequences. The analysis emphasizes on four aspects, i.e., robustness, capacity, distortion and security, each of which considers two cases, i.e., the authorized embedding and unauthorized embedding. What is more, the locally optimum detector for multi-watermarking of hybrid multiplicative rule is reduced, and some potential attacks are investigated. Additionally, for each case, some suggestions are proposed to improve the system's performance. Finally, some comparative experiments are done, and results are given to show the validity of the theoretical analysis.     

Data analytics in wireless systems and IoT issues and challenges

The emergence of data engineering along with the support of Online Social Networks is growing by millions every day due to the introduction of wireless systems and Internet of Things. The rapid growth of usage of smart devices helps to create new generation knowledge sharing platforms. Data Analytics has a major role to play in the growth and success of wireless and IoT applications. The growth of data has become exponential and is difficult to analyze. Many researchers depend on the data available on Wireless Systems and IoT for developing new generation services and applications. With the opportunity of information and communication technologies like heterogeneous networking, cloud computing, web services, crowd sensing and data mining, ubiquitous and asynchronous information sharing is feasible. But this also brings out a lot of provocations with respect to conflicting standards, data portability, data aggregation, data distribution, differential context and communication overhead. The smart information and communication technology has changed many features of human lifestyle: personal and work places.