C-V2X应用场景的算法建模及评价模型综述

V2X利用无线信息交互技术,实现车与其他实体之间的信息交互,将"人、车、路、云"交通参与要素有机地联系在一起,构建一个智慧的交通体系。算法的评价基于算法建模,通过建模梳理算法的逻辑思路,输出算法相关的标定参数,进而使算法性能达到更优。基于C-V2X应用场景的算法评价模型,旨在研究如何评判不同应用场景的实现优劣,用于设计出标准的指标参数衡量算法的性能,重点从算法计算效率和算法有效性2个维度考虑,构建起评估算法功能及性能的立体模型,多角度权衡并分析,从而对应用场景的实现给予评估反馈。     

20 MW LNG发电船方案设计与分析

针对靠港船舶清洁用电和部分港口、小型岛屿与海上平台等电力供应的快速响应问题，在阐述大型液化天然气（Liquefied Natural Gas，LNG）发电船发展现状及其主要系统基础上，引用国内外LNG船舶相关设计经验，采用模块化设计方法对20 MW LNG发电船的船体、LNG管路系统、电力-推进复合系统等进行设计，为该型船设计的主要难点问题提供可选的解决方案。     

A flexible,adaptive traffic network simulation with parameter estimation

This article deals with macroscopic traffic modeling and online parameter estimation suitable for real-time simulation of complex road configurations. A numerical model for the nonlinear hyperbolic transport equation is introduced that works with a fundamental diagram of arbitrary shape and piecewise differentiable, discontinuous initial conditions. Suitable boundary conditions at road inlets and outlets are realized. A method to identify parameters of the underlying fundamental diagram via aggregated traffic sensor data is presented and the Fisher Information Matrix is utilized to optimize traffic sensor placement. The choice of parameterization, sensor placement, and the range of sensor data affect identifiability of the parameters of the fundamental diagram. The results are validated by comparison with a microscopic traffic simulation based on a car-following model.     

基于SEEP／W的基底地下水赋存形态及孔压分析

依托SEEP／W软件和实测数据模拟地下水压力在某工程基底及侧墙的分布情况，分析在抗浮水位下的渗流物理过程，确定其基底水压力及分布规律。     

对数螺线双曲拱坝三维建模与C++程序设计

对数螺线双曲拱坝因为受力条件较好,越来越多地被应用到实际工程中.在研究对数螺线双曲拱坝各几何参数的基础上,建立了对数螺线双曲拱坝的数学模型,运用C++程序设计语言编程,在AutoCAD中实现了三维实体仿真,为拱坝下一步进行有限元分析提供了精确的三维实体模型.     

Urban activity pattern classification using topic models from online geo-location data

Location-based check-in services in various social media applications have enabled individuals to share their activity-related choices providing a new source of human activity data. Although geo-location data has the potential to infer multi-day patterns of individual activities, appropriate methodological approaches are needed. This paper presents a technique to analyze large-scale geo-location data from social media to infer individual activity patterns. A data-driven modeling approach, based on topic modeling, is proposed to classify patterns in individual activity choices. The model provides an activity generation mechanism which when combined with the data from traditional surveys is potentially a useful component of an activity-travel simulator. Using the model, aggregate patterns of users’ weekly activities are extracted from the data. The model is extended to also find user-specific activity patterns. We extend the model to account for missing activities (a major limitation of social media data) and demonstrate how information from activity-based diaries can be complemented with longitudinal geo-location information. This work provides foundational tools that can be used when geo-location data is available to predict disaggregate activity patterns.     

A system dynamics modeling for urban air pollution: A case study of Tehran,Iran

Development of strategies to control urban air pollution is a complex process involving a wide range of sciences. In this study a system dynamics model is proposed in order to estimate the behavior of parameters affecting air pollution in Tehran. The proposed model includes two subsystems: (1) urban transportation, (2) air polluting industries. In this paper, several policies are proposed to mitigate air pollution. The proposed model is simulated under several scenarios using historical data of transportation and industrial sectors in Tehran. Policies are categorized as: (1) road construction, (2) technology improvement in fuel and automotive industries, (3) traffic control plans, (4) development of public transportation infrastructures. The results show effectiveness of the proposed policies. In this case, technology improvement in fuel and automotive industries and development of public transportation infrastructures are more effective policies in order to reduce air pollution.     

江苏如东人工岛建设对周边水动力及泥沙冲淤的影响

在南黄海辐射沙洲这样一个水动力和泥沙环境都相当复杂的区域建设浅水人工岛,不仅要考虑人工岛本身的稳定型问题,还要深入地认识浅水人工岛建设引起的流场和泥沙冲淤是否造成目前潮流动力场和"水道—沙洲"系统格局的较大变异、自然演变的趋势性过程是否因人工岛建设而加速或逆转。通过整体潮流泥沙物理模型研究了西太阳沙人工岛工程对滩槽演变趋势的影响和工程区滩冲槽淤的短期波动,探讨了如东人工岛工程建设后,岛周围水动力和泥砂冲淤的变化规律,提出了相应的防冲措施。结果表明,拟建人工岛工程建设引起的水流动力变化主要在西太阳沙附近的浅水区,并局限在1.5倍人工岛直径范围内,对邻近水道深槽区的潮流动力没有影响。人工岛工程没有改变西太阳沙周边各水道潮流动力场格局,没有引致水道间潮流动力此消彼长的变化、未改变控制西太阳沙"水道-沙洲"系统演变的动力泥沙环境,西太阳沙核心部位的稳定主要取决于西太阳沙北侧潮流动力增强的自然演变过程。就人工岛建设而言,东北岛壁前沿有效的防冲护底措施对沙洲核心部位稳定和减少北水道深槽淤积泥沙来源均有积极意义。     

复杂形体远程操控水下运载器水动力阻尼模型建模和检验(英文)

In this paper,numerical modeling and model testing of a complex-shaped remotely-operated vehicle(ROV) were shown.The paper emphasized the systematic modeling of hydrodynamic damping using the computational fluid dynamic software ANSYS-CFXTM on the complex-shaped ROV,a practice that is not commonly applied.For initial design and prototype testing during the developmental stage,small-scale testing using a free-decaying experiment was used to verify the theoretical models obtained from ANSYS-CFXTM.Simulation results are shown to coincide with the experimental tests.The proposed method could determine the hydrodynamic damping coefficients of the ROV.     

System optimum and pricing for the day-long commute with distributed demand,autos and transit

The day-long system optimum (SO) commute for an urban area served by auto and transit is modeled as an auto bottleneck with a capacitated transit bypass. A public agency manages the system’s capacities optimally. Commuters are identical except for the times at which they wish to complete their morning trips and start their evening trips, which are given by an arbitrary joint distribution. They value unpunctuality – their lateness or earliness relative to their wish times – with a common penalty function. They must use the same mode for both trips. Commuters are assigned personalized mode and travel start times that collectively minimize society’s generalized cost for the whole day. This includes unpunctuality penalties, queuing delays, travel times and out-of-pocket costs for users, as well as travel supply costs and externalities for society.It is shown that in a SO solution there can be no queuing and that the set of SO solutions forms a convex set. Furthermore, if the schedule penalty that users suffer due to unpunctuality is separable into morning and evening components, then the set of commuters traveling by the same mode arrive at work and depart from work in the order of their wishes. These orders are in general different in the morning and the evening. It is also shown that there always is a SO solution in which users are at all times, and on both modes, either punctual or flowing at capacity. These problem properties are used to identify search methods, both, for SO solutions and for time-dependent tolls and transit fares that preserve the solutions as Nash equilibriums. In every case studied, these prices exist. They must peak concurrently for the two modes in both periods.In special cases involving only one mode, only one period or concentrated demand the solution to the complete problem decomposes by period conditional on the number of transit users, and this facilitates the solution. In these cases the day-long SO cost is the sum of the SO costs for the two peaks considered separately. However, this is not true in general – the solution obtained by combining the two single-period solutions can be infeasible. When this happens, the optimum day-long cost will exceed the sum of the single-period costs. The discrepancy is about 40% of the total schedule penalty for an example representing a large city. Thus, to develop realistic policies the day-long problem must be addressed head on. An approximate method that yields closed form formulas for the case with uniformly distributed wishes is presented.