城市可持续发展指数调研报告（之二）

2013年城市可持续发展指数通过对经济、社会、资源、环境等方面指标的计算分析,可以使城市明确其所处的发展阶段,明确自身存在的短板和问题,找到适合学习的榜样城市,为给更多的中国城市提供参考和借鉴,上期我们主要对报告内容做了相对详尽的介绍,本期我们将就几个典型城市做具体的案例分析,以期对调研报告有更深入的了解。     

A new heuristics model of simulating pedestrian dynamics based on Voronoi diagram

A new heuristics model based on the Voronoi diagram is presented to simulate pedestrian dynamics with the noncrowded state, in which these mechanisms of preference demand evading and surpassing, microscopic anti-deadlock, and site-fine-tuning are considered. The preference demand describes the willingness determination of detouring or following other pedestrians. In the evading and surpassing mechanisms, in order to achieve a balance between avoiding conflicts and minimizing detour distances, a new pair of concepts: "allow-areas and denial-areas" are introduced to divide the feasible region for pedestrians detour behaviors, in which the direction and magnitude of detour velocity are determined.A microscopic anti-deadlock mechanism is inserted to avoid deadlock problem of the counter-directional pedestrian. A site-fine-tuning mechanism is introduced to describe the behavior of avoiding getting too close to the neighbors in pedestrian movement. The presented model is verified through multiple scenarios, including the uni-or bi-direction pedestrian flow in the corridor without obstacles, the uni-direction pedestrian flow in the corridor with obstacles, and the pedestrian evacuation from a room with single-exit. The simulation results show that the velocity–density relationship is consistent with empirical data. Some self-organizing phenomena, such as lanes formation and arching are observed in the simulation.When pedestrians detour an obstacle, the avoiding area before the obstacle and the unoccupied area after the obstacle can be observed. When pedestrians evacuate through a bottleneck without panic, the fan-shaped crowd can be found, which is consistent with the actual observation. It is also found that the behavior of following others in an orderly manner is more conducive to the improvement of the overall movement efficiency when the crowd moves in a limited space.     

基于硬件加速的高速数据流连续实时聚集查询

近年来,动态数据流环境下的聚集查询正成为一个热点研究问题.目前的相关算法主要是采用近似技术,以牺牲精度来换取处理速度的提高.然而,在高速数据流环境下,处理速度仍然难以满足需求.软硬件协同的高速数据流处理技术逐渐引起人们的关注.提出了一种基于硬件加速的高速数据流聚集查询方法,充分发挥硬件在处理速度上的优势和软件在灵活性方面的长处.算法是增量的,也实现了多窗口资源共享.最后,给出了算法的复杂度分析并实验验证了方法的有效性.     

Automatic,long-term frequency-stabilized lasers with sub-hertz linewidth and 10-16 frequency instability

We report two ultra-stable laser systems automatically frequency-stabilized to two high-finesse optical cavities. By employing analog-digital hybrid proportional integral derivative(PID) controllers, we keep the merits of wide servo bandwidth and servo accuracy by using analog circuits for the PID controller, and, at the same time, we realize automatic laser frequency locking by introducing digital logic into the PID controller. The lasers can be automatically frequency-stabilized to their refer...     

超密集波分复用无源光网络的研究进展

超密集波分复用无源光网络凭借其信道间隔仅为几个GHz、功率预算高达几十dB等优越性能,可以实现用户数目和传输容量的大幅提升.从频谱效率提高、相干接收机简化、光子集成器件应用、数字信号处理优化等关键研究方向出发,简述了国内外关于超密集波分复用无源光网络相关研究的最新进展情况,探讨了其未来可能的研究方向和发展趋势.     

智能手机在生化传感分析中的应用进展

该文主要综述了基于智能手机生化检测的光学和电化学检测技术,及其在生化传感分析中强大的通信手段。重点介绍了智能手机集成的生化传感器技术的性能、优点,及其在生化检测中的应用,讨论了目前智能手机在生化传感分析方面存在的局限性和面临的挑战,并展望了未来的发展方向和潜在的机遇。     

关于任意四边形截面柱体扭转问题

文献[1]提出通过一个映射变换来求解任意四边形截面柱体扭转问题,本文证明了这是不可能的,并且指出用类似的方法求解任意三角形截面柱体扭转问题也是不可能的.     

一种香豆素pH荧光染料的开发及应用

香豆素类化合物具有良好的荧光光谱,已广泛运用于抗肿瘤、抗氧化、抗炎等研究.前期研究中,作者发现3-苯并咪唑-7-羟基香豆素可作为荧光探针监测细胞内pH值变化(pKa=7.20,pH 6.50～8.30).因此,该文通过在3-苯并咪唑-7-羟基香豆素C-3位苯并咪唑上引入甲氧基给电子基团,得到化合物3-(6-甲氧基-1H...     

B值鞅差序列和的收敛速度

在随机元的尾概率随机有界的情况下,我们讨论了Ｂ值鞅差序列非随机足标与随机足标部分和的收敛速度,使得实值独立同分布随机变量序列的一些经典结果得到了推广和一般化,并且当０＜ｔ＜１时,我们证明了对任意Ｂ值随机元结论都是成立的．     

计算机无线红外数字通信的实现

介绍了光天线数字通信的应用规模,探讨了基于红外线的光无线局域网的ＩｒＤＮＡ协议,组成方式,给出一种基于ＲＳ２３２接口的计算机间无线光数据通信设计实例,同数据率为９６００ｂｉｔ／ｓ,通信距离为０．５ｍ的光无线通信。