The effect of multiple time scales and subexponentiality in MPEGvideo streams on queueing behavior

Guided by the empirical observation that real-time MPEG video streams exhibit both multiple time scale and subexponential characteristics, we construct a video model that captures both of these characteristics and is amenable to queueing analysis. We investigate two fundamental approaches for extracting the model parameters: using sample path and second-order statistics-based methods. The model exhibits the following two canonical queueing behaviors. When strict stability conditions are satisfied, i.e., the conditional mean of each scene is smaller than the capacity of the server, precise modeling of the interscene dynamics (long-term dependency) is not essential for the accurate prediction of small to moderately large queue sizes. In this case, the queue length distribution is determined using quasistationary (perturbation theory) analysis. When weak stability conditions are satisfied, i.e., the conditional mean of at least one scene type is greater than the capacity of the server, the dominant effect for building a large queue size is the subexponential (long-tailed) scene length distribution. In this case, precise modeling of intrascene statistics is of secondary importance for predicting the large queueing behavior. A fluid model, whose arrival process is obtained from the video data by replacing scene statistics with their means, is shown to asymptotically converge to the exact queue distribution. Using the transition scenario of moving from one stability region to the other by a change in the value of the server capacity, we synthesize recent queueing theoretic advances and ad hoc results in video modeling, and unify a broad range of seemingly contradictory experimental observations found in the literature. As a word of caution for the widespread usage of second-order statistics modeling methods, we construct two processes with the same second-order statistics that produce distinctly different queueing behaviors     

A 4-MB on-chip L2 cache for a 90-nm 1.6-GHz 64-bit microprocessor

A 4-MB L2 data cache was implemented for a 64-bit 1.6-GHz SPARC(r) RISC microprocessor. Static sense amplifiers were used in the SRAM arrays and for global data repeaters, resulting in robust and flexible timing operation. Elimination of the global clock grid over the SRAM array saves power, enabled by combining the clock information with array select signals. Redundancy was implemented flexibly, with shift circuits outside the main data array for area efficiency. The chip integrates 315 million transistors and uses an 8-metal-layer 90-nm CMOS process.     

Aging, attention, and intelligence.

The aims of this study were (a) to find out if attentional ability factors that are separate from the well-established ability factors (e.g., fluid intelligence, crystallized intelligence, and short-term acquisition and retrieval function) can be identified, and (b) to establish, through the use of part correlations, whether attentional abilities play a role in the changes in fluid and crystallized intelligence that occur with increasing age. A battery of 36 tests (19 psychometric tests and 17 measures of attentional processes) were given to 100 people, 20 of whom were in each age decade between 20 and 70. Results indicated that three attentional factors—Search, Concentration, and Attentional Flexibility—exist at the primary-ability level and that all three define fluid intelligence at the second-order level. Results also indicate that the decline in fluid intelligence with increasing age disappears if attentional factors are parted-out. Similarly, the increase in crystallized intelligence with increasing age becomes even greater if one controls for attentional processes. I conclude that changes in attentional processes play an important part in changes in human intelligence with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SurA assists the folding of Escherichia coli outer membrane proteins

Many proteins require enzymatic assistance in order to achieve a functional conformation. One rate-limiting step in protein folding is the cis-trans isomerization of prolyl residues, a reaction catalyzed by prolyl isomerases. SurA, a periplasmic protein of Escherichia coli, has sequence similarity with the prolyl isomerase parvulin. We tested whether SurA was involved in folding periplasmic and outer membrane proteins by using trypsin sensitivity as an assay for protein conformation. We determined that the efficient folding of three outer membrane proteins (OmpA, OmpF, and LamB) requires SurA in vivo, while the folding of four periplasmic proteins was independent of SurA. We conclude that SurA assists in the folding of certain secreted proteins.     

组合拱式管桥计算机模拟设计

本文在已有成果资料的基础上，为组合拱式管桥的设计建立了常规设计表达式，并研制出组合拱式管桥计算机模拟的程序软件ＣＡＰＢＤ。该软件具有以下计算功能：（１）计算组合管拱的几何特征参数；（２）计算组合管拱自重和组合拱式管桥的竖向荷载及其材料费用；（３）分析和计算各种载荷作用下组合拱式管桥的内力；（４）组合拱式管桥各控制截面强度校核、稳定性验算以及拱支墩稳定性验算和地基承载力强度校核。     

Predictive control architecture for real-time image moments based servoing of robot manipulators

This paper presents a real-time architecture for visual servoing of robot manipulators using nonlinear based predictive control. In order to increase the robustness of the control algorithm, image moments were chosen to be the visual features which describe the objects from the image. A visual predictive architecture is designed to solve tasks addressed to robot manipulators with an eye-in-hand configuration. An implementation of the proposed architecture is done so that the capabilities of a 6 d.o.f robot manipulator are extended. The results of different experiments conducted with two types of image moments based controllers (proportional and predictive with reference trajectory) are presented and discussed.     

Y型偏心支撑加固震损RC框架的数值模拟

为研究Y型偏心支撑加固震损RC框架的抗震性能,采用有限元程序ABAQUS对RCF-YB1试验试件进行了验证分析.在此基础上系统研究了耗能梁段腹板高度对Y型偏心支撑加固震损RC框架结构抗震性能的影响,重点对比分析了加固后试件的滞回曲线、水平承载力、抗侧刚度、累积滞回耗能.结果表明,针对中等程度损伤的RC框架,采用Y型偏心支撑加固后仍可获得较大的水平承载力和抗侧刚度.此外,Y型偏心支撑的耗能梁段对加固震损RC框架的抗震性能有较大影响,随着耗能梁段腹板高度的增加,试件的水平承载力、抗侧刚度、耗能均呈增大趋势.     

Binding conformation prediction between human acetylcholinesterase and cytochrome c using molecular modeling methods

The acetylcholinesterase (AChE) is important to terminate acetylcholine-mediated neurotransmission at cholinergic synapses. The pivotal role of AChE in apoptosome formation through the interactions with cytochrome c (Cyt c) was demonstrated in recent study. In order to investigate the proper binding conformation between the human AChE (hAChE) and human Cyt c (hCyt c), macro-molecular docking simulation was performed using DOT 2.0 program. The hCyt c was bound to peripheral anionic site (PAS) on hAChE and binding mode of the docked conformation was very similar to the reported crystal structure of the AChE and fasciculin-II (Fas-II) complex. Two 10ns molecular dynamics (MD) simulations were carried out to refine the binding mode of docked structure and to observe the differences of the binding conformations between the absent (Apo) and presence (Holo) of heme group. The key hydrogen bonding residues between hAChE and hCyt c proteins were found in Apo and Holo systems, as well as each Tyr341 and Trp286 residue of hAChE was participated in cation-pi (π) interactions with Lys79 of hCyt c in Apo and Holo systems, respectively. From the present study, although the final structures of the Apo and Holo systems have similar binding pattern, several differences were investigated in flexibilities, interface interactions, and interface accessible surface areas. Based on these results, we were able to predict the reasonable binding conformation which is indispensable for apoptosome formation.     

Windows程序的基本框架和消息机制

通过对一个Windows基本程序的分析,介绍了Windows程序的 基本框架和消息机制,说明了在VB、Delphi等可视化编程环境下,实现了对上述机制的封装 。讨论了利用Windows消息驱动体系,对消息处理进行编程,让系统实现一些特殊的应用功 能。