基于GIS的乌江流域新安江模型参数率定

为了使新安江模型的运用更能真实反映流域的基本特征及产汇流机理,利用地理信息系统空间分析的功能,由数字高程模型导出乌江武隆以上流域的流域排水网,并在此基础上提取汇流长度及坡度等地形特征值。在地理信息系统平台上,计算出流域下垫面的植被、土壤、地貌等特征值,并将其与流域模型参数建立相关关系。结果表明,各流域模拟的确定性系数及模拟精度均较高。因此,预报结果更加合理,理论依据也更加可靠。     

坝体度汛及导流泄水建筑物洪水标准研究与探讨

为了进一步研究大坝度汛及导流泄水建筑物设计洪水标准问题,在收集我国已建与在建大型梯级水利枢纽大坝度汛标准及导流泄水建筑物导流设计标准和实际运用情况的基础上,研究分析了影响大坝度汛标准及导流泄水建筑物导流标准选取的因素,提出了合理选取的依据与原则。同时,结合现行规范使用中存在的问题,对大坝度汛及导流泄水建筑物标准若干问题进行分析探讨,提出相应的规范编制建议。     

Traffic-information-utilized low-complexity relay selection for two-way AF relaying networks

This paper investigates a two-way amplify-and-forward multiple relaying network (TWMR-AF) and presents a novel relay selection scheme, which is appropriate for different traffic patterns and has very low implementation complexity, rendering it very attractive for practical systems. Assuming the TWMR-AF over Nakagami-m fading, the approximate expression of the overall outage probability is derived, and the diversity and code gains are then obtained. The analytical results indicate that the proposed policy achieves better outage performance than the traditional max-min relay selection scheme, as validated by the simulation results.     

Spindle-shaped microfluidic chamber with uniform perfusion flows

The reaction chamber is important due to its wide applications. Based on the idea of the bionics, a novel spindle-shaped chamber (S-chamber) for microfluidics was designed to provide uniform flow and eliminate stagnant corners for microchannels. The computational fluid dynamics simulation results demonstrate that these S-chambers have a better performance compared to the conventional diamond-shaped chambers. An S-chamber with the optimized shape, which consists of a rectangle reaction region interfaced to the inlet/outlet channel through an expansion region with smooth arc edges, was fabricated by micromolding of polydimethylsiloxane. This S-chamber was fixed into a microreactor and mounted horizontally on a synthesizer for biochemical reactions. Solvent perfusion experiments and synthetic optimization experiments for in situ synthesis of peptide nucleic acids microarray were performed. The experimental results indicate that the newly designed and fabricated S-chamber provides excellent homogeneous perfusion flows. This type of S-chamber is designed for the most convenient fixation in the horizontal direction, without the need to consider the complicated effect caused by other housing directions. It has a wide application for cell culturing, microarray synthesis, gene hybridization, and many other microfluidic system-based techniques requiring uniform flow conditions.     

A method for shape and topology optimization of truss-like structure

We present a method for the shape and topology optimization of truss-like structure. First, an initial design of a truss-like structure is constructed by a mesh generator of the finite element method because a truss-like structure can be described by a finite element mesh. Then, the shape and topology of the initial structure is optimized. In order to ensure a truss-like structure can be easily manufactured via intended techniques, we assume the beams have the same size of cross-section, and a method based on the concept of the SIMP method is used for the topology optimization. In addition, in order to prevent intersection of beams and zero-length beams, a geometric constraint based on the signed area of triangle is introduced to the shape optimization. The optimization method is verified by several 2D examples. Influence on compliance of the representative length of beams is investigated.     

为互联网和数据中心业务定制的服务器——云计算资源池的最佳选择

随着云计算技术的不断发展,基于云计算定制的服务器在互联网和数据中心的应用日益广泛,各种解决方案层出不穷。本文通过分析服务器和云计算的技术特点,比较各种硬件解决方案的异同,确定最适合云计算资源池应用的硬件支撑方案。     

Amultiplemaneuvering targets tracking algorithm based on a generalized pseudo-Bayesian estimator of first order

We describe the design of a multiple maneuvering targets tracking algorithm under the framework of Gaussian mixture probability hypothesis density (PHD) filter. First, a variation of the generalized pseudo-Bayesian estimator of first order (VGPB1) is designed to adapt to the Gaussian mixture PHD filter for jump Markov system models (JMS-PHD). The probability of each kinematic model, which is used in the JMS-PHD filter, is updated with VGPB1. The weighted sum of state, associated covariance, and weights for Gaussian components are then calculated. Pruning and merging techniques are also adopted in this algorithm to increase efficiency. Performance of the proposed algorithm is compared with that of the JMS-PHD filter. Monte-Carlo simulation results demonstrate that the optimal subpattern assignment (OSPA) distances of the proposed algorithm are lower than those of the JMS-PHD filter for maneuvering targets tracking.     

罗圈背水库闸门自动控制系统设计与实现

上位机采用组态王软件编程,下位机利用PLC进行控制,这套控制模式在水库闸门控制系统中得到广泛应用.针对该系统的结构、实现功能和软件设计进行介绍.     

闸下海漫柔性加糙体消能防冲机理试验

通过室内水工模型试验,量测了采用废旧轮胎加糙后三维流速的分布。结果表明:加糙后近底流速明显降低,但整个断面的平均流速近似相等;随着轮胎排数的增加,水流紊流强度平均值增大,附加切应力增大,流体质点间相互混掺的情况加剧,从而使消能效率得以提高。