Multimedia Execution Hardware Accelerator

In this paper we show that some expressions frequently used in multimedia applications can be formulated as a general add-multiply-add operation. We further show a hardwired implementation of the Add-Multiply-Add instruction which is no more complex than the multiplier implementation. Furthermore we show that two frequently motion estimation operations, the Sum and Mean of Absolute Differences, can be implemented in hardware requiring also approximately the same cycle time as the multiplication. We also show that our approach can be extended easily to provide the computation of the Sum and Mean of Absolute Difference of a 16×16 pixel block in no more than four machine cycles. Additionally we propose a codec hardwired mechanism for the Paeth predictor used in the Portable Network Standard (PNG) that requires at most two general purpose ALU cycles. We extend the paeth unit to include the median, maximum and minimum operations on three inputs with no additional cycle time and we also extend the Add-Multiply-Add unit to include the mean of three numbers. Finally we propose a multimedia hardware accelerator to accommodate all the proposed operations. The proposed unit is an extension of the multiply pipeline with ALU extensions with no extra stages added. The unit operates on 32 instructions in total.     

滚切式双边剪剪刃间隙平行度偏差分析

双边剪剪刃的间隙与钢板厚度关系直接决定剪切钢板边部质量的好坏,文章主要分析剪刃间隙的平行度的不一致对钢板边部质量的影响,提出在生产过程中采取的处理方法和预防措施。     

一种六连杆式数控骨外固定器

骨穿针外固定技术是治疗骨折、严重的肢体损伤和残缺及重建患肢功能的一种主要方法,而应用最多最广的、以六自由度并联结构为基础的泰勒固定架仍存在无法实现数字化调节、数字化测量,以及本身结构缺陷等问题。设计了一种六连杆式数字化骨外固定器控制系统,使用了不同于泰勒支架结构的六自由度并联结构,利用PLC运动控制器、光栅传感器对骨外固定架进行改造设计,从而实现固定器的数字化调节及测量,由此解决当前临床使用中遇到的各种问题。     

Modeling power and energy consumption of dense matrix factorizations on multicore processors

In this paper, we propose a model for the energy consumption of the concurrent execution of three key dense matrix factorizations, with task parallelism leveraged via the Symmetric Multi‐Processing Superscalar (SMPSs) runtime, on a multicore processor. Our model decomposes the power dissipation into the system, static and dynamic components, with the former two being estimated from basic, off‐line experiments. The dynamic power, on the other hand, requires significantly more care, and we introduce a contention‐aware model that accommodates for the variability of power consumption due to memory contention. Experimental results on an Intel Xeon E5504 processor with four cores, using an internal powermeter that samples the power drawn by the mainboard with a frequency of 1 KHz, show the reliability of the energy model for the Cholesky, LU, and QR factorizations on this platform. Copyright © 2013 John Wiley & Sons, Ltd.     

一种新的使用两种比特分辨率图象的块匹配运动估计算法及其低功耗VLSI结构

本文给出了一种新的块匹配运动估计算法,它根据视频图像内容的复杂程度自适应地选择常规的或者低比特分辨率的图像来进行块匹配,并且采用了一种混合使用两种比特分辨率图像的新望远镜搜索算法.模拟结果表明,新算法具有较低的计算复杂性,并且能够保证较好的视频质量.基于该算法,我们设计了一种新的脉动阵列结构的搜索引擎.该引擎具有可分割的数据通道,从而在使用低比特分辨率图像进行块匹配时能够通过加强处理的并行性来提高吞吐率.新的运动估计器可工作在较低的时钟频率和电源电压之下,具有低的功耗消耗.     

基于多视影像匹配的三维彩色点云自动生成

针对三维虚拟场景构建的需要,提出了一种基于多视影像匹配的航空影像三维彩色点云自动生成算法.该算法采用了一种全新的物方与像方信息融合的多视影像概率松弛整体匹配策略,以综合利用多幅影像信息来提高匹配的可靠度;然后,基于多视影像匹配结果,采用多影像光束法平差来计算待匹配点的三维坐标;最后,采用平差模正确性的统计检验对三维坐标计算的准确度进行定量衡量.利用该算法对实际航空影像进行实验,统计检验得到的可靠度超过了90％,表明所提出的三维彩色点云生成方法具有较高的稳定度和精度.基于所提出的方法可将多视影像重叠区域内的所有平面像素转换为三维点,从而自动生成表达地理场景的全数字化的三维彩色点云,能很好地满足大范围三维地理场景快速重建的需要.     

Role of misfit in precipitation crystallography in non-ferrous metals

The crystallography and morphology of precipitates in different systems were rationalized based on the optimum matcing conditions. The interfaces that obey these conditions were conveniently identified in reciprocal space, in terms of three Ag＇s parallelism rules. The theoretic basis of the O-lattice and CSL/DSC theory for these rules was provided briefly. Examples of small lattice misfit system （a Ti alloy）, and large lattice misfit systems （A1 and Mg alloys） were presented. The effect of lattice parameters on the orientation relationship and morphology was also discussed.     

On the promise of general-purpose parallel computing

It has become generally accepted that continued improvements in high-performance scientific computation will be achieved only through the ‘exploitation of parallelism’. Despite the nebulous nature of this expression, enthusiasm for the potential of parallel computing has led to calls for improvements in computational performance of more than a thousand-fold in the next few years, or for what is sometimes referred to as a Teraflop (one trillion floating-point operations per second) Computer. Such a system is envisioned as a general-purpose tool for accelerating progress in such widely varied applications as astronomy, biochemistry, circuit analysis, computational fluid dynamics, global economic modeling, high energy physics, materials science, structural analysis, and weather prediction.

Although parallel architectures appear to offer the greatest promise for significant improvements in overall computational performance, it is not yet clear whether a general-purpose parallel architecture can realize the large increases solicited by the scientific community. This note will take a practical look at the prospect for general-purpose parallel computation and will consider some of the potential limitations by using a simple parametric model of computational performance.     

多视点视频编码中的视频目标提取与视差匹配

在单通道视频目标分割算法的基础上,首先提出一种多视点视频编码中的视频目标提取方案.然后提出一种基于多级块匹配视差估计算法.应用Moravec算子对视差矢量图进行检测,提取特征视差矢量并对其进行精确度检验.若特征视差矢量不够精确,则其所在块将重新进行小范围的块匹配.若块匹配误差仍太大则将其分裂为四个子块重新匹配.与传统块匹配算法相比,新方法能获得较为精确和平滑的视差场,提高重建后的图像质量.