Video super-resolution reconstruction using a mobile search strategy and adaptive patch size

In this study, a new video super-resolution (SR) reconstruction approach using a mobile search strategy and adaptive patch size is proposed. Based on the modified nonlocal-means (NLM) SR algorithm, a mobile search strategy for motion estimation and adaptive patch size are proposed to reduce the computational complexity of the proposed approach and improve the visual quality of the final video SR reconstruction results, respectively. Based on the experimental results obtained in this study, the performance (visual quality and PSNR values) of the proposed approach is better than those of three comparison approaches.     

Effects of Ca combined with Sr additions on microstructure and mechanical properties of AZ91D magnesium alloy

Abstract

Weight reduction to improve automobile fuel economy has triggered renewed interest in magnesium. The effects of Ca/Sr separate and composite additions to AZ91D magnesium alloy on its microstructure and mechanical properties have been investigated. The results indicate Ca can refine both the grain and eutectic phase of AZ91D magnesium alloy. Sr hampers microstructure refinement when composite Ca/Sr additions are made. In addition, separate Ca additions to AZ91D magnesium alloy increase yield strength but decrease elongation of this alloy. By adjusting the Ca/Sr composite proportions, additions to AZ91D magnesium alloy are able to improve both microstructure and mechanical properties of the alloy.     

A tradeoff between unit capacity and average production cost in spinning reserve optimization

In power systems the spinning reserve (SR) amount can be determined by deterministic or probabilistic techniques. Probabilistic techniques draw more attention since they can consider the economics and the stochastic nature of system behavior and component failures. In probabilistic techniques, the tradeoff between cost and reliability directly affects the SR deployment and it has been extensively analyzed. However, there is another tradeoff which reflects the compromise between the unit capacity and average production cost in the SR optimization problem. This tradeoff impacts the solution accuracy to a certain extent and influences the complexity of the model, and it has not been explicitly analyzed before. In this paper, a new SR optimization method is proposed in which the tradeoff between unit capacity and average production cost is well respected. The proposed method strikes a good balance between solution accuracy and computation efficiency and can obtain better results within a desirable run time compared with those of the previous methods. Besides, the proposed method can also be used to improve the solution of the reserve constrained unit commitment problem. It can lower the total cost by just redistributing the MW dispatch even when the SSR is fixed. The efficiency and validity of the proposed method are verified using the IEEE reliability test system.     

Review of effect of P and Sr on modification and porosity development in Al–Si alloys

Abstract

The benefits of Sr additions to Al–Si alloys to modify the eutectic are often impaired by the development of porosity, sometimes to the degree that benefits are negated. Experimental reports are reviewed in this paper, suggesting an explanation in terms of the oxide population in the melt. The unmodified silicon particles are nucleated by AlP, which has in turn nucleated on oxide bifilms. The oxide bifilms, which are essentially cracks, are straightened by the crystalline growth of Si particles, leading to increased crack size and consequently reduced mechanical properties. The addition of Sr improves properties by suppressing the formation of Si on bifilms and thereby preventing the straightening of the pre-existing cracks. Si is now forced to precipitate at a lower temperature as a coral-like eutectic. Unfortunately, the bifilms are now freed (the primary Si particles no longer exist to grow around and sequester the bifilms), remaining in suspension in the liquid metal, allowing them to act to block interdendritic flow and aid the initiation of the formation of pores, countering the benefits of the improved structure.     

栅极电荷保持技术在有源箝位同步整流正激变换器中的应用

介绍了一种应用于有源箝位同步整流的驱动电路,它适用于输出电流和功率密度较高的场合。该驱动电路采用栅极电荷保持技术,解决了副边同步整流管的死区问题,降低了同步整流管的损耗,提高了变换器的效率。详细分析了变压器副边的工作原理,并在原理样机上进行了实验验证,在满载时效率可达到89%,实验效果比较理想。     

基于改进相容函数的超分辨率图像重建

提出了一种基于机器学习的超分辨率(SR)改进算法。首先建立一个包括低分辨率(LR)图像及其相应的高分辨率(HR)图像的训练样本集,为LR图像提供了HR的图像解释。把训练集中的每一幅图像分成若干个图像块,每一个图像块作为马尔可夫随机场(MRF)模型的结点,MRF模型参数从这些训练样本中学习得到,通过对训练样本中的LR图像块进行k-均值聚类减少计算开销,并用k-均值的聚类结果提出了一种新的相容函数形式。实验结果表明,该算法是可行的,并与同类算法相比能取得较好的结果,使得SR后的图像更平滑自然。     

基于软件无线电的卫星通信模拟源的实现

介绍一种基于软件无线电的卫星通信模拟源。提出基于FPGA和高速D/A转换器的硬件系统的实现方法和设计注意事项。描述了软件系统中各模块的基本原理和功能,并根据软件无线电基本理论给出了它们的具体实现,同时给出模拟源输出信号的EVM测试结果。该系统硬件组成简单,输出信号的调制方式和数据协议可任意切换,通用性和扩展性强。     

一种非线性振子的电路模拟及其在微弱信号提取中的应用

针对数值方法求解Duffmg振子随机共振行为存在的不足,提出釆用电路模拟Duffing振子的方法,以满足实时性需求,并将该方法应用于微弱信号的提取。引入了ー种变量替换,通过这种变换可以处理频率超出随机共振理论要求范围的信号,以满足工程实际应用。实验表明：该方法适合于低信噪比条件下微弱正弦信号的检测,特別是能够从强噪声背景中提取出微弱周期脉冲信号,并且可以保持信号的相位基本不变,其效果优于常规线性滤波方法。     

一种新型同步整流式多路输出变换器研究

文中讨论了基于单端正激变换器的同步整流式多路输出DC／DC变换器的设计原理，提出了一种Buck结构后置调节器的新型方案。采用集成控制芯片UC3842进行了控制电路设计，实验结果验证了该方案的可行性。