A Heuristic Algorithm for QoS Multicast Routing

In recent years, QoS multicast routing has continued to be a very important research topic in the areas of networks. This paper presents a heuristic algorithm for the QoS multicast routing (HAQMR). This heuristic algorithm deals with delay and bandwidth constraints and has low cost. The HAQMR attempts to significantly reduce the overhead for constructing a multicast tree, the proof for correctness of the HAQMR is given, and the performance of the HAQMR is evaluated by simulations. The study shows that HAQMR provides an available approach to QoS multicast routing.     

PERSPECTIVES ON URBAN WATER INFRASTRUCTURE IN CHINA FOR THE 21~(ST) CENTURY: SDMUWEIC MODEL

Based on system dynamics approach, SDMUWEIC model is developed in order to evaluate future dynamics of urban water infrastructure development in China. Firstly, this paper presents the basic structure and characteristics of the model, focusing on water infrastructure's dynamic relationships with population increase, economic development, water resources shortage and water conservation practices. Secondly, model veracity and robustness tests based on behavior reproduction and uncertainty analyses are illustrated. Thirdly, based on the model, future patterns of China's urban water infrastructure investment requirements are simulated, and effectiveness of two different policy scenarios are evaluated. Finally, conclusions and policy implications are drawn, allowing insights into China's sustainable water infrastructure policies and managements.     

Study on Optimal Topology for Computer Local Double Loop Networks

A dist ributed optimal local double loop (DOLDL) network is presented. Emphasis is laid on the topology and distributed routing algorithms for the DOLDL. On the basis of building an abstract model, a set of definitions and theorems are described and proved. An algorithm which can optimize the double loop networks is presented. The optimal values of the topologic parameters for the DOLDL have been obtained by the algorithm, and these numerical results are analyzed. The study shows that the bounds of the optimal diameter d and average hop distance a for this class of networks are [3N- 2]≤d≤[3N ] and (5N/9 (N-1))-(3N -1.8)相似文献   

非线性最优化及其在金融中的应用

本书是根据作者在Hertfordshire大学与Bergamo大学为本科生和研究生教授非线性优化方面的讲稿编撰而成的，中心内容是非线性最优化的数值方法。     

21世纪的艺术博物馆管理员

随着21世纪的到来，博物馆管理员们也不得不面对很多新的问题，他们需要了解信息技术的发展，需要跟上时代的步伐。本书中收录的若干文章着重讨论了有关博物馆管理员今天所面临的问题。     

兴奋性-抑制性的平衡突触、回路、系统

兴奋性和抑制性的理想平衡是大脑正常功能和可塑性的根基，而当前对神经元的研究中，很大程度上忽视了细胞同时涉及到兴奋-抑制两方面平衡网络系统这一事实。我们对于兴奋性突触传递和修饰有着比较深入的理解，而对于抑制性中间神经元和它们对应的可塑性的探索则大大落后。本书以一种兴奋．抑制均衡的整合方式对神经元的有关功能进行了阐述，侧重于大脑各区域各种水平上这种平衡的建立、保持、修饰过程，同时结合神经学研究中多项最新方法、技术，为读者展示了分子水平、细胞水平直到系统水平上神经科学的多项研究热点。     

Solving multi-object radar cross section based on wide-angle parabolic equation method

1. INTRODUCTION The parabolic equation (PE) was first introduced to treat the problems of diffraction of radio waves around the earth by Leontovich and Fock[1,2]. It’s a full-wave technique based on splitting the wave equation into two parabolic equations: outgoing and incoming parabolic wave equation, which describes the forward and backward propagating fields. The solution is marched from plane to plane along some preferred direction (say, paraxial direction). This technique reduces t…     

理查德·斯通——1984年诺贝尔经济学奖获得者

在第十六届诺贝尔经济学奖颁发仪式上,剑桥大学的理查德·斯通独占鳌头,荣膺全奖。在这一领域中,学人雅士们分享如此硕大的殊誉历来屡见不鲜,瑞士皇家科学院断然定论,旨在强调斯通将整体国民收入核算体系公式化的重要性。二次世界大战后的实践证明,斯通的核算体系具有极其重大的实际意义。     

美国──加拿大尼亚加拉大瀑布的发育演化

本文在分析尼亚加拉地区第四纪冰川与河谷成因联系的基础上，论述了现代大瀑布的发育、演化及年代学问题；详细探讨了瀑布区的地质特征、控制瀑布及峡谷后退稳定性的地貌过程；最后讨论了瀑布将来的发展趋势。