Profile-Driven Component Placement for Cluster-Based Online Services

The growth of the Internet and of various intranets has spawned a wealth of online services, most of which are implemented on local-area clusters using remote invocation (for example, remote procedure call/remote method invocation) among manually placed application components. Component placement can be a significant challenge for large-scale services, particularly when application resource needs are workload dependent. Automatic component placement has the potential to maximize overall system throughput. The key idea is to construct (offline) a mapping between input workload and individual-component resource consumption. Such mappings, called component profiles, then support high-performance placement. Preliminary results on an online auction benchmark based on J2EE (Java 2 Platform, Enterprise Edition) suggest that profile-driven tools can identify placements that achieve near-optimal overall throughput.     

超级电容器在汽车启动中的应用

根据超级电容器的结构特性,介绍在汽车启动过程中如何利用超级电容器减小对车内其他电子设备的干扰,改善汽车的启动性能,延长蓄电池使用寿命.     

基于手写笔的多功能电子白板系统的实现

该文针对当前电子白板系统对个性化支持的不足,引入手写笔作为输入设备,充分利用其功能参数,设计开发了具有模拟毛笔、钢笔、铅笔等真实笔特征的多笔型功能的电子白板系统。     

On the physical and logical topology design of large-scale optical networks

We consider the problem of designing a network of optical cross-connects (OXCs) to provide end-to-end lightpath services to large numbers of label switched routers (LSRs). We present a set of heuristic algorithms to address the combined problem of physical topology design (i.e., determine the number of OXCs required and the fiber links among them) and logical topology design (i.e., determine the routing and wavelength assignment for the lightpaths among the LSRs). Unlike previous studies which were limited to small topologies with a handful of nodes and a few tens of lightpaths, we have applied our algorithms to networks with hundreds or thousands of LSRs and with a number of lightpaths that is an order of magnitude larger than the number of LSRs. In order to characterize the performance of our algorithms, we have developed lower bounds which can be computed efficiently. We present numerical results for up to 1000 LSRs and for a wide range of system parameters such as the number of wavelengths per fiber, the number of transceivers per LSR, and the number of ports per OXC. The results indicate that it is possible to build large-scale optical networks with rich connectivity in a cost-effective manner, using relatively few but properly dimensioned OXCs.     

欧洲主要电信运营商专线资费的演变

欧洲主要电信运营商所处国度的经济和人口布局情况不同，竞争环境也有差别，在专线资费方面的做法也有许多不同之处。考虑到地区之间竞争的差异。目前多数国家都取消了地区交叉补贴的做法，但还有一部分国家仍然坚持统一费率。在资费方面的基本促销手段为接合同年限和用户的支出额打折。从2000年到2003年资费演变的基本情况是；接入费扣2Mbit／s以下较低速率的专线租费保持平稳略有下降，较高速率专线的租费则有较大的下调幅虚。     

微表处技术在高速公路养护中的应用

结合某高速公路专项治理工程,采用施工用原材料研究了微表处混合料的设计,结合实体工程研究了微表处技术的施工工艺。对微表处的应用效果进行了跟踪观测,研究结论表明沥青路面微表处技术是一种经济、性能优良的高速公路养护技术。     

Propulsive performance and vortex shedding of a foil in flapping flight

Summary. The propulsive performance and vortex shedding of an oscillating foil, which mimics biological locomotion, are investigated based on a computational fluid dynamics analysis. The objectives of this study are to investigate unsteady forces, in particular a thrust force, for the foil in pitching and plunging motion, and to deal with the relations of the propulsive performance with leading-edge vortex structure and vortex shedding in the near wake. The two-dimensional incompressible Navier–Stokes equations in the vorticity and stream-function formulation are solved by fourth-order essentially compact finite difference schemes for the space derivatives and a fourth-order Runge-Kutta scheme for the time advancement. To reveal the mechanism of the propulsive performance, the unsteady forces and the shedding of the leading- and trailing- edge vortices of the foil in the pitching and plunging motion are analyzed. Based on our calculated results, three types of the leading-edge vortex shedding, which have an effective influence on the vortex structures in the wake of the oscillating foil, are identified. The effects of some typical factors, such as the frequency and amplitude of the oscillation, the phase difference between the pitching and plunging motions, and the thickness ratio of the foil, on the vortex shedding and the unsteady forces are discussed.     

鄂尔多斯盆地东部奥陶系盐下储层预测

鄂尔多斯盆地奥陶系的膏盐岩沉积面积达5×104km2,天然气的勘探程度很低。为此,利用测井技术和地震反演技术对盐下储层进行了预测。首先,通过对盐下沉积特征的综合分析,对盐下储集层段的发育层位和主要储集岩类型进行了描述;然后,采用ELAN测井技术对盐下储层的物性进行了分析,认为盐下储层的物性在普遍较差的背景上存在相对发育的层段和区带;最后,利用全局优化多道地震反演技术,对岩下储层进行了预测,认为盐下存在的局部隆起是圈闭和储层发育的有利区带。     

橡胶促进剂DM的合成工艺

M氧化生成DM是自由基反应机理，结合微反应器机理，采用分子氧化的反应方式，选用绿色溶剂异丙醇、环境友好型氧化剂H202，一步法制取高品质DM。对反应时间、反应温度、氧化剂用量等因素进行考察，确定最佳工艺条件为：反应时间90min，反应温度55℃，氧化剂不过量，碱过量5％，M—Na溶液M含量30％，加料时N60 min，溶剂用量为M—Na溶液质量的1．5倍，所得产品质量合格，熔点可达180℃。     

铁路罐车密闭装车计量系统的运行分析

从中国石化股份公司济南分公司新上铁路罐车密闭装车计量系统的背景出发，阐述该系统的设计思想和组成；通过分析实际运行过程中仪表比对数据，讨论影响仪表贸易交接准确性的各种因素，提出相应的解决方法；最后通过铁路罐车密闭装车计量系统投用效果。证实该系统可产生明显的经济效益。