Energy-Saving and Punctuality Combined Velocity Planning for the Autonomous-Rail Rapid Tram with Enhanced Pseudospectral Method

Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the requirements of energy-saving and punctuality.An ART velocity pre-planning and re-planning strategy based on the combination of punctuality dynamic programming(PDP)and pseudospectral(PS)method is proposed in this paper.Firstly,the longitudinal dynamics model of ART is established by a multi-particle model.Secondly,the PDP algorithm with global optimal characteristics is adopted as the pre-planning strategy.A model for determining the number of collocation points of the real-time PS method is proposed to improve the energy-saving effect while ensuring computation efficiency.Then the enhanced PS method is utilized to design the velocity re-planning strategy.Finally,simulations are conducted in the typical scenario with sloping roads,traffic lights,and intrusion of the pedestrian.The simulation results indicate that the ART with the proposed velocity trajectory optimization strategy can meet the punctuality requirement,and obtain better economy efficiency compared with the punctuality green light optimal speed advisory(PGLOSA).

Users’ Perception on Operation and Performance of Public Transport Systems in African Developing Countries: The Case of Bus Rapid Transit (BRT) in Dar es Salaam City, Tanzania

Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops.

Modeling customer satisfaction for bus rapid transit in Changzhou, China

This paper aims to develop a customer satisfaction model for bus rapid transit （BRT）. Both the socio-economic and travel characteristics of passengers were considered to be independent variables. Changzhou BRT was taken as an example and on which on-board surveys were conducted to collect data. Ordinal logistic regression （OLR） was used as the modeling approach. The general OLR-based procedure for modeling customer satisfaction is proposed and based on which the customer satisfaction model of Changzhou BRT is developed. Some important findings are concluded： Waiting sub-journey affects customer satisfaction the most, riding sub- journey comes second and arriving station sub-journey has relatively fewer effects. The availability of shelter and benches at stations imposes heavy influence on customer satisfaction. Passengers＇ socio-economic characteristics have heavy impact on customer satisfaction.

Impact of viscosity modifier on asphalt properties used for bus rapid transit lanes in Chengdu

In order to find the effect of different viscosity modifier dosages on asphalt binder＇s performance in bus rapid transit lanes in the city of Chengdu, three different viscosity modifiers were analyzed： TAFPACK-super （TPS）, high-viscosity additive （HVA） and road-science- technology （RST）, and four different asphalt binders were investigated through laboratory experiments. The percent- ages of the viscosity modifiers used were： TPS （0%, 8%, 10%, 12%, 14% and 16%） and RST and HVA （8% and 12%） depending on the type of asphalt binder. Technical indicators of modifier asphalt were tested through con- ventional and unconventional binder tests. It has been found out that only a percentage greater than or equal to 14% TPS is reasonable to achieve the requirement set by 20,000 Pa. s for the 60℃ dynamic viscosity on local #70 grade asphalt. The results indicate that conventional bin- ders did not meet the requirements of the 60℃ dynamic viscosity when 12% of TPS or HVA modifiers were used. In addition, the B-type styrene-butadienne-styrene （SBS） modified asphalt binder has better viscosity balance than the A-type SBS modified when 8% of each of the three different kinds of viscosity modifiers is used. Therefore, the B-type modified SBS thus appears to be a suitable choice in asphalt mixtures for bus rapid transit lane with the 60℃ dynamic viscosity.

Fabrication of VO_2 thin film by rapid thermal annealing in oxygen atmosphere and its metal–insulator phase transition properties

Vanadium dioxide thin films have been fabricated through sputtering vanadium thin films and rapid thermal annealing in oxygen. The microstructure and the metal-insulator transition properties of the vanadium dioxide thin films were inves- tigated by X-ray diffraction, X-ray photoelectron spectroscopy, and a spectrometer. It is found that the preferred orientation of the vanadium dioxide changes from （111） to （011 ） with increasing thickness of the vanadium thin film after rapid thermal annealing. The vanadium dioxide thin films exhibit an obvious metal-insulator transition with increasing temperature, and the phase transition temperature decreases as the film thickness increases. The transition shows hysteretic behaviors, and the hysteresis width decreases as the film thickness increases due to the higher concentration carriers resulted from the uncompleted lattice. The fabrication of vanadium dioxide thin films with higher concentration carriers will facilitate the nature study of the metal-insulator transition.

Integrated Performance Measures for Bus Rapid Transit System and Traffic Signal Systems Using Trajectory Data

Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions.

Dwell time estimation models for bus rapid transit stations

Bus rapid transit （BRT） systems have been shown to have many advantages including affordability, high capacity vehicles, and reliable service. Due to these attractive advantages, many cities throughout the world are in the process of planning the construction of BRT systems. To improve the performance of BRT systems, many researchers study BRT operation and control, which include the study of dwell times at bus/BRT stations. To ensure the effectiveness of real-time control which aims to avoid bus/BRT vehicles congestion, accurate dwell time models are needed. We develop our models using data from a BRT vehicle survey conducted in Changzhou, China, where BRT lines are built along passenger corridors, and BRT stations are enclosed like light rails. This means that interactions between passengers traveling on the BRT system are more frequent than those in traditional transit system who use platform stations. We statistically analyze the BRT vehicle survey data, and based on this analysis, we are able to make the following conclusions： （ I ） The delay time per passenger at a BRT station is less than that at a non-BRT station, which implies that BRT stations are efficient in the sense that they are able to move passengers quickly. （II） The dwell time follows a logarithmic normal distribution with a mean of 2.56 and a variance of 0.53. （III） The greater the number of BRT lines serviced by a station, the longer the dwell time is. （IV） Daily travel demands are highest during the morning peak interval where the dwell time, the number of passengers boarding and alighting and the number of passengers on vehicles reach their maximum values. （V） The dwell time is highly positively correlated with the total number of passengers boarding and alighting. （VI） The delay per passenger is negatively correlated with the total number of passengers boarding and alighting. We propose two dwell time models for the BRT station. The first proposed model is a linear model while the second is nonlinear. We introduce the conflict between passengers boarding and alighting into our models. Finally, by comparing our models with the models of Rajbhandari and Chien et al., and TCQSM （Transit Capacity and Quality of Service Manual）, we conclude that the proposed nonlinear model can better predict the dwell time at BRT stations.

An Apparatus Design for the Vehicle Control Scheme in Personal Rapid Transit System

A new transportation technology known as personal rapid transit （PRT） is being developed by multiple different companies around the world, and one system is under commercial operations in the United Kingdom. Each design is different, but they all share a need to operate many automated transit vehicles at very close headways. Safe operation will require a level of control an order of magnitude above any current transit system. As a result, new techniques will be needed for the development and testing of the mechanical and control systems. In this paper an apparatus for developing and testing a PRT vehicle control scheme is demonstrated. This system is composed of independent modules that represent virtual vehicles, a central control system, a man-machine interface and a monitoring device. It can be used to implement and to evaluate the designed vehicle control algorithm. The vehicle control algorithm is designed and simulated in a combined simulation platform that consists of Matlab/Simulink and Labview Simulation Interface Toolkit. Simple operational scenarios are proposed for the testing of the proposed vehicle control apparatus.

Optimizing Performance of atgrade Intersection with Bus Rapid Transit Corridor and Heterogeneous Traffic

Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries.However,in developing countries like India,the right–of-way for most of the roads is restricted and traffic is heterogeneous in nature.Provision of BRT in existing right–ofway reduces the capacity available for other motorized traffic.As the buses travel with a certain frequency on dedicated bus-ways,the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle(MV)lanes suffers from congestion.The problem gets severe at intersections.However,if buses are operated in mixed traffic it is no more rapid transit.Hence,a solution is required to address this problem and optimize the performance of traffic as a whole.This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection,and bus lanes(beyond that)are made available to all the motorized vehicular traffic(heterogeneous traffic)at intersection.The performance evaluation is done in terms of average queue length,maximum queue length,average delay time per vehicle,vehicle throughput,average speed in network and emission of Carbon monoxide CO,mono-nitrogen oxides NOx and Volatile organic compounds(VOC).It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length,maximum queue length,average delay time per vehicle and emission per vehicle,while there is an increase in vehicle throughput and average speed of all the vehicles in the network.Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network.Results of investigation are relevant in international context.VISSIM,a microscopic simulation tool,is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The effect is investigated with different random seeds to obtain reasonable results for analysis.

市域快线行车组织在埃及斋月十日城铁路项目中的应用研究

为适应我国社会经济和新型城镇化发展,市域铁路正呈现蓬勃发展的态势。埃及斋月十日城铁路项目作为为中资公司“走出去”的第一条成功执行的市域快线,与其功能需求和技术特点相匹配的行车组织关键技术和方法在海外推广具有一定的难度。该论文简述了埃及轨道交通发展历程及现状,总结了项目的主要特点,阐述了车辆选型、速度目标值及站立标准的确定,分析了辅助配线设置方案,探讨了快慢车行车组织模式的可行性,提出了线路多次延伸后列车开行方案的设想。

基于快速评价方法的土地利用变化分析

为构建快速评价方法,及时掌握区域土地利用变化动态,促进土地资源的科学合理利用,推进自然资源可持续发展,利用影像自动分割技术,对2010年、2020年两期遥感数据进行地类信息采集,利用ArcGIS模型构建技术,采用土地利用动态变化度、地学信息图谱及土地利用转移矩阵等方法对研究区土地利用情况进行综合分析。结果显示,2010—2020年研究区林地面积增加244.81 hm~2,住宅用地面积增加69.68 hm~2,水域及水利设施用地面积增加33.60 hm~2;耕地和草地面积分别减少262.81 hm~2、30.71 hm~2,其他地类面积变化不大。从土地利用动态变化度来看,公共管理与公共服务用地增幅显著,达到24.62%。从地学信息图谱及土地利用转移矩阵来看,林地增加来源地类主要为耕地、园地及草地,整个研究区域均有分布,主要受到退耕还林政策及在影像分割和目视解译过程中的林下耕地影响。通过一系列研究较快地摸清了土地利用数量、布局及各地类之间相互转化的剧烈程度,可为土地利用可持续发展及相关部门开展研究提供决策依据。

过渡金属纳米酶的调控及其在食品检测中的应用

与生物酶相比,高效过渡金属纳米酶凭借其多酶活性、可调酶活性、高稳定性以及低成本,在食品安全检测中展现了突出的应用潜力,在食品工业领域具有多样化的应用前景。近年来,这类纳米酶在食品检测领域的发展逐步扩大,检测物质种类不断拓宽,检出限不断降低,检测范围不断扩大,为食品安全快速检测提供了新途径。然而,相关应用仍存在提高特异性、酶活稳定性和降低生物毒性等困难,同时还需解决回收和成本效益等方面的问题。因此,本文从高效过渡金属纳米酶酶活性分类及其催化机制出发,围绕过渡金属纳米酶性能评价以及调控策略展开系统性论述,重点关注过渡金属纳米酶的类酶活性、性能调控方法,以及它们在食品安全快速检测领域的应用进展,以期为合理设计高性能纳米酶提供有效参考。

透析液中结缔组织生长因子、纤溶酶水平与腹膜透析患者腹膜溶质转运速率的关系

目的 探讨透析液中结缔组织生长因子(CTGF)、纤溶酶原激活物抑制剂-1(PAI-1)水平与腹膜透析(PD患者腹膜溶质转运速率(PSTR)的关系。方法 选取2020年1月至2022年12月江苏省连云港市第二人民医院收治的152例PD患者,根据标准腹膜平衡试验分为快速转运组和非快速转运组。采用酶联免疫吸附试验检测透析液中CTGF、PAI-1水平。采用多因素logistic回归分析PD患者PSTR快速转运的影响因素,采用受试者操作特征曲线分析透析液中CTGF、PAI-1水平对PD患者PSTR快速转运的评估价值。结果 152例PD患者PSTR快速转运发生率为57.24%(87/152)。快速转运组透析液中CTGF、PAI-1水平高于非快速转运组(P<0.05)。快速转运组透析龄、夜间超滤量高于非快速转运组,白蛋白水平低于非快速转运组(P<0.05)。透析龄延长(OR=1.051,95%CI:1.023~1.081)和CTGF(OR=1.298,95%CI:1.165~1.446)、PAI-1(OR=1.408,95%CI:1.205~1.646)升高为PD患者PSTR快速转运的独立危险因素(P<0.05)。透析液中CTGF联合PAI-1预测PD患者PSTR快速转运的曲线下面积大于二者单独预测(P<0.05)。结论 透析液中CTGF、PAI-1水平升高与PD患者PSTR快速转运独立相关,二者联合对PD患者PSTR快速转运评估价值较高,可能成为PD患者PSTR快速转运的辅助评估指标。

自适应循环发动机快速推力变化过渡过程性能初步研究

自适应循环发动机是基于变循环发动机设计理念基础并充分考虑飞发一体化设计、热管理等综合性能的面向未来飞行平台的先进动力装置,可通过诸多可调机构实现发动机涵道比、增压比、流量以及工作模式的灵活改变,从而适应不同飞行任务的复杂任务剖面需求,获得更大飞行包线内的性能优化。本文基于自适应循环发动机的性能计算仿真模型,在相关研究基础上结合模式转换和加减速过程实现快速推力变化过程,根据模式转换与加减速控制规律设计,开展典型算例下的快速推力变化过渡过程性能分析并验证其控制规律设计方法可行性,在亚声速巡航工况下,发动机在以M3模式叶尖风扇最小角度状态下,低压转子相对物理转速从0.6加速至1.0,最大可使终止推力增大32.4%,相较于单一模式加减速过渡过程,推力变化范围更宽,加速时间更短,转速变化范围更小。

某160 km/h市域快速轨道交通地下线环境振动特性试验研究

随着城镇化的快速发展,城市范围拓展地越来越大。目前地铁设计速度多为80~120 km/h,对于长距离通勤略显不足。为了更好地实现城市融合,更高速度的城市轨道交通应运而生,并已经在某些城市投产运营。为掌握160 km/h市域快速轨道交通地下线产生的环境振动影响,对某城市160 km/h市域快速轨道交通地下线开展系统的环境振动测试,包括钢轨、道床、隧道壁振动测试;地面振动和室内二次结构噪声测试。结果表明:列车速度在124~152 km/h时,钢轨振动为109.7~111.2 dB,道床振动为75.6~77.4 dB,隧道壁振动为67.5~69.4 dB,平均速度138 km/h时,隧道壁振动为68.7 dB;列车振动传至地面后,隧道正上方距离轨道0~40 m地面振动最大Z振级为46.4~60.2 dB,地面振动基本符合随距离加大而减小的衰减规律,但是距离轨道10 m处测点的振动响应较0 m处测点存在放大现象;采取橡胶隔振垫整体道床情况下,近、远轨列车通过时隧道上方建筑物一层室内二次结构噪声最大值分别为32.7 dB(A)、28.4 dB(A)。

北京市中心城区外地铁线路开行快慢车对策研究

随着城市化进程的进一步加快,城市居民对通勤出行的时效性要求越来越高,连接中心城与外围新城之间的地铁是主要的通勤交通线路,如何提高其旅行速度、缩短乘客旅行时间,成为急需研究的一个重要问题。为满足不同乘客对出行条件和服务效率的需求,提出通过开行快慢车实现旅速时间的节省。从既有客流特征入手,分析客流来源及目的地,指出既有线开行快慢车的必要性;在借鉴日本相关案例经验的基础上,对开行快慢车需要考虑的问题进行分析;以北京燕房线、房山线、15号线为例,分析不同线路的客流特征及线路条件,分别提出利用大行车间隔及设置越行线开行快慢车的方案;并提出两种方案的特点及实施要点。利用大行车间隔开行快慢车,即在客流较小的线路上利用富裕的能力开行快慢车,仅需对运营图进行优化设计,投资小;设置越行线开行快慢车,需根据工程实施条件、客流特征,选择合理的越行站点。经分析研究,采用两种方式均可实现节省旅行时间的目的,对提升中心城区外客流快速进城需求有积极的意义。

Critical evaluation of transit policies in Lima,Peru;resilience of rail rapid transit(Metro)in a developing country

This paper evaluates rail transit within the context of the transit policies implemented in Lima,Peru.First it reviews the implementation of rapid transit,and bus reform.Secondly,it evaluates the outcomes of such policies by using Total Factor Productivity for policy effectiveness,Data Envelopment Analysis for rapid transit performance,and Generalized Cost of Travel for improvements.This paper finds that implementation failed in enforcing key requirements for rail transit regarding penetration of CBD and short transfers to bus transit;and that the basic assumptions of bus reform did not hold regarding bus oversupply,bus congestion or bus pollution.This paper also finds that outcomes of policies failed dramatically in achieving the planning goals;however,rail transit(Metro)shows high level of resilience in serving large ridership at high speed.On the other hand,bus reform was associated with a disproportionate increase of motorization,well over the effect of income growth or car attractiveness,and more related to the excessive reduction of bus transit capacity ill-advised from unproved bus reform assumptions.This paper recommends expanding rail rapid transit due to its intensive use of green renewable energy and its potential of demand growth if combined with modern Intelligent Transportation services,but this opportunity can be wasted without the proposed policy constraint to achieve lower Generalized Cost of Travel at any governmental intervention for bus reform,instead of just reducing bus transit capacity as implemented.Finally,this paper recommends government to government contracts to build rail transit and to enforce proper planning.

国家地震烈度速报与预警工程项目建设与业务运行的过渡实践

国家地震烈度速报与预警工程项目已完成建设任务,面对政府、社会、公众对地震预警的期待,结合新一代地震监测速报预警业务体系特点,在由项目建设转向业务运行过程中,采取尽早树立业务化观念、建立健全制度体系、制定完善组织体系、形成风险隐患排查整改长效机制、重点地区先行及渐进式投入试运行等措施手段,在项目竣工验收前初步完成过渡,全面进入业务运行状态,部分重点地区提前开通对外服务。本文分析了各方对地震预警的期待和新一代速报预警业务体系特点,总结了建设转运行的过渡措施,并探讨了目前运行管理工作中的问题及改进方向,为未来地震预警工作完善提供参考。

旱涝急转对大豆产量和生长发育影响

为研究旱涝急转对大豆产量和生长发育的影响,通过开展旱涝急转组、单旱组、单涝组和对照组平行对比形式的旱涝急转测筒试验,分析了大豆不同试验处理条件下叶绿素含量变化规律、大豆前期受旱再继续受涝的产量变化规律以及不同旱涝组合形式下先旱与后涝相互作用的产量变化规律,进一步探究了旱涝互作对产量构成因素的影响。研究成果为旱涝急转防灾、减灾提供理论依据和技术支撑。

首尔都市区轨道交通演进特征及启示

[目的]深入掌握国外发达都市区轨道交通演进历程,有利于我国超大、特大城市建构科学的轨道交通线网形态,安排合理的建设时序。首尔都市区与我国超大城市空间结构和轨道交通发展基础有更强的类似性,更值得深入研究。[方法]采用案例比较与演绎的研究方法,总结了首尔都市区人口与土地空间演进历程特征,分别研究了地铁、都市快轨、准高速通勤快线等的供给特征。[结果及结论]首尔都市区轨道供给存在普遍性规律,也有其独特性。我国超大城市都市快轨供给不具备首尔都市区的历史条件,且受空间形态影响,因此其里程占比应远小于首尔都市区的;站间距指标对实现都市快轨预定职能有重要的保障意义。