用于多处理器媒体SoC设计的实时总线调度优化策略

为了减少多处理器媒体系统芯片（SoC）总线任务调度过程中的处理器性能损失，从减少总线任务冲突的角度出发，提出了改变任务属性和调整任务优先级相结合的总线任务调度优化策略.在保证任务实时性的前提下，通过增加原有任务可执行时间，将原有任务划分为多个子任务，动态调整任务优先级，充分利用总线的空闲时间执行部分任务，减少了总线任务冲突，降低了处理器因等待数据源而引起的性能损失.将该方法应用于多处理器媒体系统芯片MediaSoC3221A的设计中，当进行运动图像专家组（MPEG）实时解码时处理器的性能损失从原来的4.7%减小到0.1%.     

FILTRONS AND THEIR ASSOCIATED RING COMPUTATIONS

Certain special computational models called the filter automata (FA) are presented. We use them in iterative, pipelined processing of discrete sequences. Such computations reveal characteristic moving, periodic objects, with soliton-like properties referred to as the filtrons. Filter automata play the role of a transmitting medium or a field, while filtrons behave like waves or particles

We characterise FA by showing their distinguishing features, and fillrons—by introducing some parameters, such as edge numbers, number of FA cycles involved, distribution of internal idle pulses, etc. We show that filtrons may be generated in parallel by a multiprocessor ring net. This means that each filtron has its associated ring computation. If such a computation succeeds then its companion filtron exists, too. The link between filtrons and their ring computations is established simply by the filtron edge numbers. This gives a method of calculating a whole filtron if its edge number and supporting FA are known, and of looking for possible filter automata capable of supporting a prescribed filtron

A number of FA computational phenomena, recently discovered, are also presented. Some of them call for physical experiments to verify to what extent the filter automata may model physical reality. We believe that such experiments could be performed in optical fibres using solitons of light.     

面向多处理器的实时周期任务容错调度算法研究

主副版本策略是多处理器系统实时任务调度中处理容错问题的一种重要方式.根据分布式控制系统的特点,本文提出一种改进的FTRMBF算法-PR-FTRMBF,以提高系统周期任务的可调度性.在FTRMBF等已有的调度算法中,当没有处理器分配给当前副版本时,将为副版本分配新的处理器;本文提出的改进算法则以回溯的方式重新分配主版本.在保证系统实时性能和容错能力的前提下,节省了处理器数目.仿真实验表明,与FTRMBF算法相比,改进算法显著提高了系统任务的可调度性.     

Multi-objective two-stage multiprocessor flow shop scheduling – a subgroup particle swarm optimisation approach

Flow shop production system – compared to other economically important production systems – is popular in real manufacturing environments. This study focuses on the flow shop with multiprocessor scheduling problem (FSMP), and develops an improved particle swarm optimisation heuristic to solve it. Additionally, this study designs an integer programming model to perform effectiveness and robustness testing on the proposed heuristic. Experimental results demonstrate a 10% to 50% improvement in the effectiveness of the proposed heuristic in small-scale problem tests, and a 10% to 40% improvement in the robustness of the heuristic in large-scale problem tests, indicating extremely satisfactory performance.     

对称分布的若干性质及对称贝努利分布的应用

探讨了具有对称分布的随机变量的若干性质,并应用对称贝努利分布给出了一个重要的三角恒等式的证明.     

基于对称螺旋型电感和差分二极管的2.4GHz CMOS正交输出压控振荡器

提出了一种产生2.4GHz正交本地振荡信号的方法.它将LC-VCO和两级环路振荡器两种结构组合起来以实现正交输出的低相位噪声压控振荡器.LC网络是由在片对称螺旋型电感和差分二极管组成的.详细论述了VCO原理及其噪声性能.该电路已经用0.25μm单层多晶、五层金属N阱CMOS数字工艺制作.测量结果表明:它可以提供正交的本地振荡信号,其振荡频率可以在300MHz的范围内调节,当仅对差分输出振荡信号的一端进行测试时,振荡频率为2.41GHz时,去偏移中心为600kHz时的相位噪声为-104.33dBc/Hz.而且,它能在很低的电源电压下工作,功耗也很低,所以,它在集成收发机中将得到广泛的应用.     

二极管泵浦Nd∶YVO_4倍频激光器使用的光学薄膜

讨论了二极管泵浦 Nd∶ YVO4 激光器中使用的一系列光学薄膜 ,膜系类型涉及截止滤光片、增透膜等。根据设计对称匹配膜层的分析 ,利用计算机膜系设计优化软件对膜系进行优化 ,得到损耗小、利于制备、重复性好的膜系设计。用于实际制备 ,取得较好的效果     

Problem size scaling in the presence of parallel overhead

In this paper we study the performance of applications on multiprocessor systems. In particular we investigate the effect of synchronization and parallelization overhead where the fact that part of the application may be inherently sequential is taken into account. By relating our assumptions to an earlier work by Flatt and Kennedy we establish that the overhead function can be characterized using the concept of convex functions. In order to observe a satisfactory payoff for increased processing power it is essential to increase the problem size accordingly. We discuss linear and nonlinear scaling schemes and compare the corresponding asymptotic performance behaviour. Throughout this investigation we profit from the well developed mathematical apparatus of convex functions.     

钢筋混凝土小偏心受压构件对称配筋的计算方法探讨

将复杂的三次方程式化为一元三次方程标准形式,利用数值分析中的二阶收敛迭代法,简便、准确地求出了相对计算受压区高度ξ值,利用ξ-p、q'相关图,提高了求解速度和精确度,计算思路清晰、公式简单,手算与电算均很方便,适用于工程设计人员在不同工作环境下进行计算校核.     

Scattering on a ring of processors

In this note, we prove that the complexity of scattering in an oriented ring of p processors is (p - 1) (β + Lτ) where L is the length of the messages, β the communication startup, and τ the elemental propagation time.