考虑路径特性的道路交通网络冗余性分析

为探究路段特性对路径冗余的影响以及突发事件下道路交通网络的冗余能力,在传统道路网络路径冗余数量方法的基础上,考虑有效路径之间的效率差异和重叠程度,构建基于路径多样性以及突发事件下冗余能力的冗余性评估模型;分析不同成本对路径多样性的影响和突发事件对冗余能力的影响,并对冗余能力进行敏感性分析。结果表明:道路交通网络中路径多样性取决于出行路径成本的类别以及路段出行成本之间的差异,路段出行成本越接近,有效路径的数量越多,路径多样性越高;突发事件场景下道路网络冗余性取决于失效路段的重要程度,失效路段越重要,网络冗余性越低;出行成本容忍度在一定范围内的增加有助于提高突发事件下道路网络的冗余能力,过高或过低的出行成本容忍度都不会对网络的冗余能力有较为明显的提高。

地铁隧道环境下2.4 GHz频段路径损耗特性

基于射线跟踪法建立地铁隧道环境下2.4GHz频段的无线信道模型,分析此场景下断面类型、收发位置、断面面积和天线极化对路径损耗特性的影响,为系统设计提供参考.

On-body propagation characterization based on FDTD method for 2.4/5.2/5.7 GHz wearable body sensor networks

The on-body path loss and time delay of radio propagation in 2. 4/5.2/5.7 GHz wearable body sensor networks （W-BSN） are studied using Remcom XFDTD, a simulation tool based on the finite-difference time- domain method. The simulation is performed in the environment of free space with a simplified three- dimensional human body model. Results show that the path loss at a higher radio frequency is significantly smaller. Given that the transmitter and the receiver are located on the body trunk, the path loss relevant to the proposed minimum equivalent surface distance follows a log-fitting parametric model, and the path loss exponents are 4. 7, 4. 1 and 4. 0 at frequencies of 2. 4, 5.2, 5.7 GHz, respectively. On the other hand, the first- arrival delays are less than 2 ns at all receivers, and the maximum time delay spread is about 10 ns. As suggested by the maximum time delay spread, transmission rates of W-BSN must be less than 10^8 symbol/s to avoid intersymbol interference from multiple-path delay.

“部编本”小学语文教材中阅读教学的改革

“部编本”小学语文教材是目前最新的小学语文教材,自投入使用以来大受社会各界关注和认可。过去小学语文教材存在的局限性和乏味性,在先进教学理念的引导下,需要增添许多符合时代发展、更贴近学生生活的内容,使学生更易理解、更感兴趣。在全面分析“部编本”小学语文教材阅读教学编写特性的同时,提出了几条促进阅读教学有效实施的路径。

Characterizing urban road runoff quality in South China:a case study in Shenzhen

In order to have an in-depth understanding of road runoff characteristics and the linkages to their influential factors this paper investigates the road runoff quality in a city of South China Shenzhen.Four rainfall events with different characteristics are monitored on a typical urban road.It is noted that the road runoff quality is worse than Grade Ⅳ of environmental quality standards for surface water.This means that the road runoff has posed a serious risk to water environment health. Furthermore the research outcomes indicate that first flush highly varies with rainfall patterns and pollutant species.This means that for road runoff treatment design rainfall patterns as well as pollutant species should be taken into consideration and this is particularly essential to design first flush capturing devices. Additionally the threshold of an initial 3 to 5 mm rainfall depth is suggested to the first flush capturing device design.These results provide useful suggestions to the effective road runoff treatment design.

Radio Channel Measurements and Analysis at 2.4/5GHz in Subway Tunnels

There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment services(e.g.,Internet,etc.) to passengers as well.The wireless channel in tunnels is quite unique due to the confined space and the waveguide effects.Therefore,modeling the radio channel characteristics in tunnels is critically important for communication systems design or optimization.This paper investigates the key radio channel characteristics of a subway tunnel at 2.4 GHz and 5 GHz,such as the path loss,root mean square(RMS) delay spread,channel stationarity,Doppler shift,and channel capacity.The field measurements show that channel characteristics in tunnels are highly location-dependent and there exist abundant components in Doppler shift domain.In the straight section of the subway tunnel,the measured path loss exponents are close to1.6,lower than that in free space.

Analysis of the Characteristics and Model of Online Social Network Information Dissemination

Online social network is increasingly showing a significant impact and role in many areas of social life. In the study of online social network related issues have become the consensus of the academic and industrial communities and the urgent need for. This paper mainly studies the problem of information dissemination in social network, the mode of communication, behavior, propagation paths and propagation characteristics are studied, and take the Tencent micro-blog as an example, based on the analysis of many examples, several main models and characteristics of information dissemination in social network platform.

Spatiotemporal distribution characteristics of bridge deck runoff

The spatiotemporal characteristics of bridge deck runoff under a natural rainfall event are explored. The Taizhou Bridge is taken as a study case,and a hydrodynamic model based on the two-dimensional shallow water equations is used to analyze the runoff characteristics. The results indicate that the runoff velocity rate and depth are positively related to rainfall intensity,yet they have different response degrees to it. The inlet’s effect degree on lane water film has a positive relationship with rainfall intensity. A natural logarithm function( R^2= 0.706) can illustrate this relationship. However,the inlet’s effect degree on ponding at the curb shows a negative relationship with the rainfall intensity. A negative exponential function( R^2= 0.824) can reveal this relationship. With the decrease in the longitudinal slope SL,the ponding depth at the curb increases significantly at the bridge approach slab,whereas the lane water film thickness( WFT) is almost unchanged,but the lane WFT increases greatly at the location with the minimum longitudinal slope. It is concluded that the characteristics of the bridge deck runoff present apparent spatiotemporal differences,the inlet ’s effects on bridge deck runoff are quantitatively correlated with rainfall intensity, and the effective drainage measures are necessary for the bridge approach slab.

Research on the adjustment model of ventilation characteristic parameters based on integrated method of circuit and path

Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious.

Transition psychology： the membership approach

China＇s social transformation since reform and opening up in 1978 has provided a unique social laboratory for Chinese researchers of social psychology. In order to describe, understand and interpret the psychological and behavioral logic of the Chinese people, we need to call on social psychology research or social transition psychology research that looks directly at social transition, in order to go beyond the cultural exceptionalism and static society approaches. Multiple group membership is the potential core construct of such a psychology.

Image feature optimization based on nonlinear dimensionality reduction

Image feature optimization is an important means to deal with high-dimensional image data in image semantic understanding and its applications. We formulate image feature optimization as the establishment of a mapping between highand low-dimensional space via a five-tuple model. Nonlinear dimensionality reduction based on manifold learning provides a feasible way for solving such a problem. We propose a novel globular neighborhood based locally linear embedding (GNLLE) algorithm using neighborhood update and an incremental neighbor search scheme, which not only can handle sparse datasets but also has strong anti-noise capability and good topological stability. Given that the distance measure adopted in nonlinear dimensionality reduction is usually based on pairwise similarity calculation, we also present a globular neighborhood and path clustering based locally linear embedding (GNPCLLE) algorithm based on path-based clustering. Due to its full consideration of correlations between image data, GNPCLLE can eliminate the distortion of the overall topological structure within the dataset on the manifold. Experimental results on two image sets show the effectiveness and efficiency of the proposed algorithms.