构皮滩升船机中间渠道通航隧洞和渡槽的尺度研究

构皮滩水电站通航建筑物采用带二级中间渠道的三级垂直升船机方案,其中第一级中间渠道由单线通航隧洞、渡槽、明渠及错船段组成。采用水工物理模型和船模试验,对第一级中间渠道的航行水力条件、单线通航隧洞和渡槽的尺度进行了系列研究。结果表明,船舶航行阻力、下沉量和渠道内水位波动随着船舶航速的增大而增大,一定航速条件下,渠道内还将产生横波,对船舶航行安全影响较大,应避免;错船段和单线渠道的连接应平顺,并应注意船舶从单线渠道航行至错船段时,因阻力减小,造成航速突然增大的影响。试验提出了不同航速条件下的单线通航渠道合理尺度,优化了错船段的位置,建议单线渠道宽采用18 m,水深不小于3.0 m,船舶航速小于等于1.2 m/s。     

水声定位信号脉冲挑选方法

能否有效的从带有各种脉冲干扰的脉冲序列中挑选出测距信号的直达声,是水声跟踪定位系统能否正确定位的关键。文章从分析脉冲序列结构及各类型脉冲特征入手,对脉冲挑选方法展开研究,并在实验室测试及海上试验中得到有效验证。     

双模turbo码在光无线通信系统中的应用

光无线通信（OWC）技术结合了光纤通信和无线电通信的优势,随着半导体激光器技术和光电探测器件的日益完善而重新兴起。光无线通信具有宽带大容量、安装快捷、机动灵活、低成本、无需频率申请等优点,具有广阔的应用前景。但光无线通信是以大气信道作为传输媒介,因此大气信道对光无线通信系统的影响较大。文章主要针对光无线通信系统中大气信道的干扰而采取的信道编码方案双模turbo码技术开展了深入的理论研究。     

多途信道短慕线时间反转聚焦研究(英文)

The existence of a multi-path channel under the water greatly decreases the accuracy of the short baseline positioning system.In this paper,the application of a time reversal mirror to the short baseline positioning system was investigated.The time reversal mirror technique allowed the acoustic signal to better focus in an unknown environment,which effectively reduced the expansion of multi-path acoustic signals as well as improved the signal focusing.The signal-to-noise ratio(SNR) of the time reversal operator greatly increased and could be obtained by ensonifying the water.The technique was less affected by the environment and therefore more applicable to a complex shallow water environment.Numerical simulations and pool experiments were used to demonstrate the efficiency of this technique.     

基于质量管理体系的海事履约机制建设思考

文中总结了《海事履约体系管理标准》的特点,结合过程方法阐述了履约体系建设思路,并提出了海事履约体系建设展望。     

浙江省科技城防洪规划浅析

结合浙江省科研机构创新基地(科技城)防洪工程规划和设计,对山区城市防洪的特点、洪水量确定、布置要求等内容进行总结分析,可为山区城市防洪泄洪系统的建设提供借鉴经验。     

Percolation phenomenon in connected vehicle network through a multi-agent approach: Mobility benefits and market penetration

This paper presents an integrated multi-agent approach, coupled with percolation theory and network science, to measure the mobility impacts (i.e., mean travel time of the system) of connected vehicle (CVtio) network at varying levels of market penetration rate. We capture the characteristics of a CV network, i.e., node degree distribution, vehicular clustering, and giant component size to verify the existence of percolation phenomenon, and further connect the emergence of mobility benefits to the percolation phase transition in the CV network. We show the percolation phase transition properties to appear in a dynamic CV network with time-correlated link and node dynamics. An analytical framework was developed to evaluate the CV network attributes with varying market penetrations (MP) and connection ranges (CR) to identify percolation phenomenon in a mixed CV and Non-CV environment. In addition, a multi-agent CV simulation platform was created to further measure (1) how varying MPs and CRs affect the network-wide mobility measured by the mean travel time of the network; and (2) when percolation transition occurs in CV network to capture the critical MP and CR. Percolation phenomenon in CV network was further validated with the analytical assessments. The results show that (1) percolation phase transition phenomenon is a function of both market penetration and communication range; (2) percolation phase transitions in both mobility and CV network are highly correlated; (3) the application can reduce the average travel time of the system by up to 20% with reasonable market penetration and communication range; (4) critical market penetration is sensitive to communication range, and vice versa; (5) at least 70% of the CVs on the network are required to show in the same cluster for mobility benefits to appear; and (6) for high levels of MP or CR, a low probability of connectivity (PC) does not dramatically change the mean travel time. These results provide solid supports to create evidence-driven frameworks to guide future CV deployment and CV network analysis.     

An energy-efficient scheduling approach to improve the utilization of regenerative energy for metro systems

Regenerative braking is an energy recovery mechanism that converts the kinetic energy during braking into electricity, also known as regenerative energy. In general, most of the regenerative energy is transmitted backward along the pantograph and fed back into the overhead contact line. To reduce the trains’ energy consumption, this paper develops a scheduling approach to coordinate the arrivals and departures of all trains located in the same electricity supply interval so that the energy regenerated from braking trains can be more effectively utilized to accelerate trains. Firstly, we formulate an integer programming model with real-world speed profiles to minimize the trains’ energy consumption with dwell time control. Secondly, we design a genetic algorithm and an allocation algorithm to find a good solution. Finally, we present numerical examples based on the real-life operation data from the Beijing Metro Yizhuang Line in Beijing, China. The results show that the proposed scheduling approach can reduce energy consumption by 6.97% and save about 1,054,388 CNY (or 169,223 USD) each year in comparison with the current timetable. Compared to the cooperative scheduling (CS) approach, the proposed scheduling approach can improve the utilization of regenerative energy by 36.16% and reduce the total energy consumption by 4.28%.     

Deep subterranean railway system: Acceptability assessment of the public discourse in the Seoul Metropolitan Area of South Korea

The objective of this study is to analyze the public acceptability of deep subterranean railway systems, which will be constructed in the space 40 m below ground level and will be operated at twice the speed of the existing subway system. Although such railway systems have been feasible in terms of construction technologies and economics, public acceptability must be considered for the successful introduction of such a new public infrastructure. Therefore, to perform the analysis of public acceptability, a telephone-based survey was conducted for residents in the vicinity of the planned the deep subterranean railway systems. As a result, about 70% of the respondents answered that they took a neutral or opposing attitude to introducing the deep subterranean railway systems. Awareness of the deep subterranean railway systems has a positive impact on its acceptability. In addition, the acceptability is found to show a negative relationship with environment and inconvenience factors. Based on the analysis results, an affective approach through soft measures such as awareness campaigns and advertisements is recommended to effectively address and mitigate the concerns and issues raised by the public.     

A simple nonparametric car-following model driven by field data

Car-following models are always of great interest of traffic engineers and researchers. In the age of mass data, this paper proposes a nonparametric car-following model driven by field data. Different from most of the existing car-following models, neither driver’s behaviour parameters nor fundamental diagrams are assumed in the data-driven model. The model is proposed based on the simple k-nearest neighbour, which outputs the average of the most similar cases, i.e., the most likely driving behaviour under the current circumstance. The inputs and outputs are selected, and the determination of the only parameter k is introduced. Three simulation scenarios are conducted to test the model. The first scenario is to simulate platoons following real leaders, where traffic waves with constant speed and the detailed trajectories are observed to be consistent with the empirical data. Driver’s rubbernecking behaviour and driving errors are simulated in the second and third scenarios, respectively. The time–space diagrams of the simulated trajectories are presented and explicitly analysed. It is demonstrated that the model is able to well replicate periodic traffic oscillations from the precursor stage to the decay stage. Without making any assumption, the fundamental diagrams for the simulated scenario coincide with the empirical fundamental diagrams. These all validate that the model can well reproduce the traffic characteristics contained by the field data. The nonparametric car-following model exhibits traffic dynamics in a simple and parsimonious manner.