Simulation of the urban climate variations in connection with the transformations of the city of Nantes since the 17th century

The paper seeks to quantify the effect of urban politics on the microclimate of the city of Nantes (France), in particular those initiated by the sanitarians in the mid-19th century to find a remedy for the insalubrity that had been developing with urban densification since the late 17th century. Intensive historical research was first carried out in order to define and date the major transformations undergone by the city, its structure (densification, then widening of the streets, filling of water courses), the lifestyle habits (heating) or the building practices (appearance of stone and paving, higher buildings, insulation). This led to the definition of 5 characteristic states of the city, in 1680, 1756, 1835, 1880 and 1945.     

包容性增长与城市规划范式转换

文章简要剖析了包容性增长的内涵,认为城市规划要想促进实现包容性增长,就必须有利于转型、公平和民生,这使传统上以经济增长为核心、自上而下规划模式,无论是理念、方法还是关注重点都需要进行根本性的范式转换。     

Integration of Low-Impact Development into the International Stormwater BMP Database

Low impact development (LID) strategies are being encouraged in many communities as an approach to reduce potential adverse impacts of development on receiving streams. Many questions exist regarding how well various LID strategies perform in different settings, just as similar questions have been raised regarding performance of traditional stormwater best management practices (BMPs). Whereas historical focus on BMP performance has been water quality concentrations or loads, characterization of volume reduction benefits for both conventional and LID practices is increasingly an objective of researchers and stormwater managers. More than a decade ago, Urban Water Resources Research Council (UWRRC) members worked to develop a set of standardized monitoring and reporting protocols for traditional BMPs and to establish a master database for the purpose of evaluating BMP performance and the factors affecting performance. This effort culminated in the International Stormwater BMP Database (www.bmpdatabase.org), which contains data for more than 360 BMPs and continues to operate as a clearinghouse for stormwater BMP data and performance analyses. During 2008–2009, the International Stormwater BMP Database project expanded to better integrate LID into the database and develop a set of metrics that can be used to characterize BMP performance with regard to surface runoff volume reduction. This paper provides a condensed overview and progress report on the LID-focused effort, including the following topics: (1)?monitoring guidance for LID at the overall site development level, (2)?an overview of recent changes to the International Stormwater BMP Database to better accommodate LID studies, (3)?a summary of LID studies currently included in the database, and (4)?a proposed approach for evaluating performance of LID studies with regard to reducing surface runoff volumes.     

城市增长边界的性质及划定方法探讨——杭州市生态带保护与控制规划实践

随着我国城市化进程加速推进,城市增长与土地资源和生态环境保护等矛盾已日益凸显。划定城市增长边界(UGB)是协调建设与生态保护的有效手段。结合杭州生态带规划案例,对城市增长边界的性质进行辨析,提出刚性UGB与弹性UGB的区别。运用生态敏感性分析、景观生态安全格局构建和建设用地规划等方法,以及面对建设与保护冲突的规划决策方法,探讨了UGB的划定方法,并指出UGB在我国规划应用中需要进一步完善的方面。     

县域城乡规划空间管制的途径研究

本文结合县情实际,依据新颁布的《城乡规划法》,探索提出了构建覆盖县域、层次清晰、目标明确、管理有序、执法有据、可操作性强的完整的城乡规划体系的途径。     

Transient phenomena of current and field distortion due to dynamics of packet‐like charges in LDPE films

Simultaneous measurements of space charge and external current were carried out using a PEA measurement system with an electrometer on the back of a grounding electrode in order to clarify the physical situation of a huge packet of positive space charges in LDPE films. A large number of positive charges from a semiconducting anode were accumulated at the interface between LDPE and an Al‐cathode at a mean applied field of 1.5 MV/cm and then finally disappeared. The results of simultaneous measurements showed that the external current kept a relatively high value during charge accumulation and further increased when the charges disappeared. Both the charge dynamics and the external current were restricted by addition of a low‐molecular‐weight paraffin wax, indicating that carrier transport was influenced by the microstructure of the polymer. The dynamics of the residual charges after short‐circuiting is also discussed. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(4): 10–17, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21256     

机载光通信平台振动模拟系统的设计与实验

设计了基于音圈电机(VCM)和压电陶瓷(PZT)快速倾斜镜(FSM)的双级振动模拟系统,用于模拟光通信中机载平台对光束的扰动。振动模拟系统结合了VCM和PZT的优点,使得模拟系统角度分辨率为1μrad,在不经过光路的放大或压缩的情况下,光束振动幅度为124mrad。验证结果表明,系统模拟的美国Altair无人机振动功率谱密度函数与其输入的无人机功率谱密度函数的相关系数为0.93,真实再现了机载平台的振动特性。机载振动模拟系统的构建为后期光通信中跟踪控制系统的设计与优化奠定了基础。     

纯方位目标跟踪极坐标模型的状态空间变换方法

在纯方位目标跟踪定位研究领域里,采用极坐标模型,可以实现可观测状态和不可观测状态的分离,但非线性的系统方程使算法的具体实现非常困难。利用状态空间的变换,可避免直接计算非线性函数雅可比矩阵的值,减小了计算量,提高了滤波稳定性。     

Group-based user pairing for virtual MIMO in LTE

A user pairing method is proposed to improve the throughput gain of virtual multiple input multiple output (virtual MIMO) in 3G long-term evolution (LTE).The approach taken in this study separated the user pairing into four steps 1) the users are divided into two groups according to their signal-to-noise ratio (SNR), and different user pairing metrics are proposed for each group; 2) the scheduler chooses a user for transmitting by a given rule; 3) the scheduler searches the pairing candidate for the selected user in each group; 4) the scheduler chooses the final pairing user from the co-group and crossover-group candidates by using a marginal utility function, to balance fairness and efficiency.The method can improve the throughput of users with high SNR, and guarantee fairness for users with low SNR, so it can be used in 3G LTE systems.The article provides both theoretical analysis and simulation results to support the idea.     

Cooperative detection and protection for Interest flooding attacks in named data networking

Named data networking (NDN) is a new emerging architecture for future network, which may be a substitute of the current TCP/IP‐based network, for the content‐oriented data request mode becoming the future trend of development. The security of NDN has attracted much attention, as an implementation of next‐generation Internet architecture. Although NDN is immune to most current attack, it cannot resist the distributed denial of service like attack – Interest flooding attack (IFA) – effectively. IFA takes advantages of the forwarding mechanism of NDN, flooding a large number of malicious Interest packets at quite a high rate, and exploits the network resources, which may cause the paralysis of the network. Taking into account the severity of the destruction, we propose an algorithm to counter such new type of attack. We analyze three properties of IFA, and use them to judge and filter Interest packets. Vector space model and Markov model are used in our method to realize a cooperative detection. Meanwhile, we present the retransmission forwarding mechanism to ensure legitimate user request. The ndnSIM module of ns3 is used for the corresponding simulation, and results of the simulation will be given to show the effectiveness of our algorithm. Copyright © 2014 John Wiley & Sons, Ltd.