多GPU系统虚实地址转换架构研究

近年来,随着大数据的发展,GPU应用的数据集规模急剧增加,这对GPU的处理能力提出了挑战。由于摩尔定律即将达到极限,提升单一GPU的性能变得越发困难,而多GPU系统通过提升GPU处理器级的并行性,成为应对该挑战的一种解决方案。GPU制造商对内存虚拟化的支持进一步简化了多GPU系统的编程,提升了资源利用率。内存虚拟化需要地址转换的支持,而地址转换的开销对系统性能具有重要影响。研究了多GPU系统中2种常见的地址转换架构,即分布式地址转换架构和集中式地址转换架构,通过模拟实验对2种架构进行了深度分析和比较,在此基础上提出了优化地址转换设计的建议。

一种模型转换分类方法及其在QVT中的应用

针对模型驱动的软件开发过程中潜在的交互性和一致性问题,介绍了一种模型转换分类的方法MTCM。根据模型和模型所描述的系统以及使用的建模语言的不同对模型转换进行细粒度的分类,然后按照此分类方法对OMG组织提出的模型转换标准QVT(查询/视图/转换)进行研究,并通过一个经典的模型转换实例即从UML模型到RDBMS模型的转换进行验证。分析得出结论,MTCM方法有助于提高模型转换的准确性和高效性。

Application of laminated vierendeel truss in high-position transfer story structure

To meet the demands for large space and flexible compartmentation ofbuildings, laminated vierendeel trasses are adopted in high-position transfer story structures.First the bearing characteristics are analyzed, in which reasonable stiffness ratio of the upperchord, middle chord, and lower chord is derived. Then combined with an actual engineering model (1:8similar ratio), the static loading and pseudo-dynamic tests of two models for laminated vierendeeltrass used in transfer story structures are conducted, in which one model adopts reinforcedconcrete, and the other adopts prestressed concrete and shape steel concrete. Seismic behaviors areanalyzed, including inter-story displacement, base shear-displacement skeleton curves, andequivalent viscosity-damping curves. A program is programmed to carry out the elasto-plastic dynamicanalysis, and displacement time-history curves of the two models are derived. The test and analysisresults show that the laminated vierendeel trass with prestressed concrete and shape steel concretehas excellent seismic behaviors. It can solve the disadvantages of laminated vierendeel trussesused in transfer story structures. Finally, some design suggestions are put forward, which can bereferenced by similar engineering.

A Novel Optical Burst Mesh Network with Optical Time Slot Interchange at Source Nodes

In this paper, we propose an optical burst network architecture supporting the ge- netic mesh topology. The intermediate node architecture of the mesh network can be the same with current wavelength switching Wave- length Division Multiplexing （WDM） net- works, and thus can reuse existing deployed infrastructure. We employ a novel Optical Time Slot Interchange （OTSI） at the source nodes for the first time to mitigate the burst conten- tion and to increase the bandwidth utilization. Time- and wavelength-domain reuse in the OTSI significantly saves optical components and red- uces blocking probability.

A framework to create video-transition effects

The paper presents a framework for developing a variety of video transition effects. The framework is designed to deal with the problem of inefficiency for programmers to generate more and more diversified video transition, which is caused by excessive coupling between the sub-modules of the system. So the framework is designed to be modular, flexible and extensible. Based on the analysis of common features of different effects, the implementation of video transition effect is divided into 4 sub-odules, each of which can be designed and developed independently. Furthermore, these sub-modules can be easily sub- stituted, modified and reused. We present a formal description of our framework, and give typical study cases to show the extensive utility of the framework.

Recommendations for construction of a nonlinear international Terrestrial Reference Frame

The problems of ITRF2008,the latest International Terrestrial Reference Frame,are pointed out and analyzed as follows:(1) ITRF is not a mm-level Terrestrial Reference Frame;(2) the origin of ITRF is neither the Earth's center of mass (CM) nor the center of figure (CF);(3) the scale of ITRF is not a uniform system in the sense of the gravitational theory of relativity.These problems result from the linear hypothesis used in the establishment and maintenance of ITRF,which includes the linear hypothesis of the coordinates definition of the ITRF reference stations,and the seven coordinate transformation parameters (three translation parameters,three rotation parameters,and one scale parameter) when the ITRF combine solution is constructed.The linear hypothesis of the ITRF construction leads to the current terrestrial reference frame only at the cm-level,which cannot satisfy the requirements of monitoring mm-level crust movements as well as the global environment.This article points out that the construction of a mm-level Terrestrial Reference Frame is actually a leap from linear to nonlinear.Therefore,according to the main characteristics of nonlinear changes of the crust's deformation,the geocenter motion and the overall height fluctuation of the Earth,the new ITRF station coordinates definition and the new observation equations of combined solutions are constructed for the realization of a mm-level nonlinear ITRF,which can solve the problems of the current ITRF.

Porous carbon matrix-encapsulated MnO in situ derived from metalorganic frameworks as advanced anode materials for Li-ion capacitors

Conversion-type anode materials hold great potential for Li+storage applications owing to their high specific capacity,while large volume expansion and poor electrical conductivity limit their rate and cycling performances.Herein,a bimetal ZnMn-based metal-organic framework(ZnMn-MOF)is engineered for in situ conversion of MnO-encapsulated porous carbon(MnO/PC)composite.The templating and activation effects of coordinated Zn endow the converted PC matrix with a highly porous structure.This enhances the compatibility of PC matrix with MnO particles,resulting in the full encapsulation of MnO particles in the PC matrix.More significantly,the PC matrix provides enough void space to buffer the volume change,which fully wraps the MnO without crack or fracture during repeated cycling.As a result,MnO/PC shows high charge storage capability,extraordinary rate performance,and long-term cycling stability at the same time.Thus MnO/PC exhibits high delithiation capacities of 768mA h g^(-1)at 0.1Ag^(-1)and 487mA h g^(-1)at a high rate of 0.7Ag^(-1),combined with an unattenuated cycling performance after 500 cycles at 0.3Ag^(-1).More significantly,MnO/PC demonstrates a well-matched performance with the capacitive activated carbon electrode in a Li-ion capacitor(LIC)full cell.LIC demonstrates a high specific energy of 153.6W h kg^(-1)at 210W kg^(-1),combined with a specific energy of 71.8W h kg^(-1)at a high specific power of 63.0kW kg^(-1).