Process variability-induced NoC link failure: A probabilistic model

As technology scales down, the amount of process variations increases causing Networks-on-Chip (NoC) links, designed to be identical, to have current and delay variations. Thus, some links may fail to meet design timing or power constraints. Using current and delay variations with design constraints, we estimate link failure probability across NoC links. Modeling results show that the average NoC link failure probability across a 4×4 mesh reaches 3.3% for voltage mode (VM) links and 3.7% for current mode (CM) links at 32 nm. The average NoC link failure probability also increases as the supply voltage decreases or the operating frequency increases. As NoC mesh size scales from 4×4 to 8×8, the link failure probability doubles to 8% for VM links at 22 nm. Topology evaluation shows that for small NoC size, the grid topology outperforms the tree one with lower amount of variation. On the other hand, for relatively large NoC sizes, the hierarchical tree and ring topologies outperform the grid topology with lower amount of variations across the links.     

次最优鲁棒调节器设计

本文介绍了一种系统参数具有有限变化的次最优鲁棒调节器设计的新方法.我们假设系统可以由一个标称矩阵集合(A_0,B_0,C_0)及对应于K个不同工作条件下的矩阵集合(A_i,B_i,C_i),i=1,2,…,K来表示,通过使用一个包含有状态变量对其标称值的增量项的推广二次型性能指标最小,来获得一个固定的输出反馈增益矩阵F;同时也介绍了一种有关最优定常输出反馈问题的大范围收敛的算法,并以一个实际的飞行控制系统说明了该固定输出反馈矩阵F是鲁棒最优的.     

稀疏正交普鲁克回归处理跨姿态人脸识别问题

正交普鲁克分析是 一种常用的处理矩阵近似问题的技术。最近,该技术被引入到正交普鲁克回归模型中来处理人脸姿态识别问题并取得了不错的效果。然而,这个模型对残差项使用了矩阵F范数约束,使得模型对于一些噪声(比如光照)非常敏感。为解决该问题,用更加鲁棒的1范约束替代原始的矩阵F范数约束,提出稀疏正交普鲁克回归模型。该模型可以由一个有效的交替迭代算法解决。在几个流行的人脸数据库上做了验证实验,实验结果证明该模型可以有效地处理人脸姿态变化。     

Effects of hydrogen direct injection on engine stability and optimization of control parameters for a combined injection engine

As engine stability is a crucial issue for engine performance and toxic emissions, an experimental research has been conducted to analyze the effects of hydrogen direct injection on engine stability. The experiments have been divided into two parts. The first set is aimed to analyze different parameter characteristics with and without hydrogen direct injection, and the second set tries to find optimal control regions. Excess air ratios, spark timings, engine speeds and engine loads are chosen as primary parameters in the study. The results show hydrogen addition can increase brake thermal efficiency by a range from 6% to 13%, enhancing the lean burn performance. Combustion duration has been shortened to about 80% by adding 10% hydrogen mixture into gasoline. Besides, Hydrogen addition makes the mixture further insensitive to ignition timings, and narrows the optimal regions with higher excess air ratios. Under medium engine speeds, the highest CoV_IMEP locates in the low load region for pure gasoline, while this maximum value appears in the medium load region for 10% hydrogen mixture. In addition, the specific value of CoV_IMEP with 10% hydrogen is rather small compared to pure gasoline. Thus, hydrogen direct injection can significantly improve engine stability and reduce controlling difficulties.     

从文学变异学角度重新审视翻译等值研究

翻译＂等值＂或等效问题是译学界长期争论的焦点问题。语言学派和文化学派分别从语言学角度和文化视角对此提出了各自的见解。比较文学变异学将翻译中的变异作为研究支点,＂跨语际变异研究＂成为译学研究的新范式,通过研究不同国家之间文学现象交流的变异状态,探究并揭示文学变异现象的内在规律性,对翻译研究有重要的启示意义。     

Interspecific Variation in Defense Secretions of Malaysian Termites from the Genus <Emphasis Type="Italic">Bulbitermes</Emphasis>

The chemicals of the defense secretions of Malaysian Bulbitermes, B. singaporensis, B. germanus, B. sarawakensis, and Bulbitermes sp. B, show that B. singaporensis is distinct from the other species, which are themselves closely related; the genetic distance between B. singaporensis and B.germanus is 0.71. B. singaporensis contains tetracyclic kempane, and B. germanus and B. sarawakensis contain tricyclic trinervitene; Bulbitermes sp. B contains a mixture of kempane and trinervitene. The mono- and diterpenoid compositions are species-specific.     

考虑组分呈梯度分布的挥发性油藏注气驱数值模拟研究

运用CMG中GEM组分模块对挥发性油藏注气驱进行数值模拟研究。首先基于低渗透正韵律地质模型,分别模拟了油藏流体为等组分和考虑组分梯度分布在不同层位注气/生产点的动态特征,用饱和度分布及油气界面张力2项指标展示了不同层位注气/生产时储层中流体物性的变化规律,结果表明对于特殊类型油藏采用数值模拟优选注气驱完井层位时应当充分考虑组分的梯度分布。然后采用正交试验设计方法对挥发性油藏注气驱影响因素进行敏感性分析,给出了挥发性油藏在不同类型储层中的最佳注气方式。表明挥发性油藏注气驱方法研究时应充分考虑油藏流体呈组分梯度分布,据此可以有效地指导该类油藏的注气方法及应用。     

A New Modified Compositional Viscosity Model for Medium-heavy Oils

Viscosity of heavy oils is a key parameter in designing potential enhanced oil recovery methods. The recently proposed semiempirical viscosity model by Lindeloff et al. (2004) Lindeloff, N., Pedersen, K. S., Rønningsen, H. P. and Milter, J. 2004. The corresponding states viscosity model applied to heavy oil systems.. J. Can. Pet. Technol., 43: 47–53. [Web of Science ®] , [Google Scholar] was studied in depth. This model is the simplest yet powerful tool for medium-heavy oil viscosities. Based on the analysis, appropriate adjustments have been suggested, with the major one being the division of the pressure-viscosity profile into three different regions. New modifications have improved the overall fit, including the saturated viscosities at low pressures. The %AAD for the data sets studied was found to be 1.37. However, with the limited geographically diverse data, it is not possible to make a comprehensive predictive model. A few limitations of the new model are also stated.     

Comparison of Simulation Methods in Gas Condensate Reservoirs

Formation of condensate bank around a gas condensate well due to reduction in bottom-hole pressure below its dew point will impose a significant reduction on the well productivity owing to a sharp fall in the gas effective permeability. Hence a better understanding and modeling of this behavior will lead to a more precise prediction of reservoir performance. Therefore the objective of this work was to make a comparison between different simulation methods of gas condensate reservoirs in order to check the validity of them respect to the most accurate one (i.e., fine grid) fully compositional model. This study shows that the modified black oil model would be adequate to simulate depletion cases above and below gas condensate dew point. However, the two phase pseudo-pressure method is not always applicable in simulating gas condensate reservoirs especially in the presence of high velocity flow effects.