内河航道制图与电子航道图一体化生产

内河航道制图与S-57标准电子航道图数据一体化生产技术可以避免空间数据的重复建设,提升内河航道测量数据的应用价值.在剖析了制图数据和S-57标准电子航道图数据差异性的基础上,设计了内河航道制图与S-57标准电子航道图数据一体化生产流程,制定了空间数据生产规范,并采用北京清华山维公司的EPS平台,实现了内河航道制图与S-57标准电子航道图数据一体化生产技术.实践结果表明,该技术合理、实用、高效,可广泛应用于我国内河数字航道建设.     

风翼-柴油机混合动力船主机降速模式

为了探索风翼-柴油机混合动力船主机降速航行模式,分析了风翼船机桨的能量传递,以及风翼助航对船舶阻力和主机的影响.分别研究了定速航行和定功率航行两种主机降速航行模式的特点.通过对比得出定速航行更适合于风翼-柴油机混合动力船舶,为风翼-柴油机混合动力船舶的推广应用提供了理论依据.     

长江三峡两坝间泄洪期船舶上水过滩能力研究

三峡-葛洲坝两坝间河段是川江船舶航行最困难的航段之一。研究在该航段航行的3种船型在泄洪期安全上水过滩的通航能力,分析计算相关船型在各种流量流速条件下安全上水过滩应具备的对水航速和对岸航速,总结出两坝间河段最危险的航段,为船舶安全上水过滩和有关部门制定船舶安全通行的政策和限制政策提供依据。     

基于现场试验的高铁路基智能压实过程中振动波垂向传播机制

以京雄城际铁路固安车站的路基段作为试验场地,从时域、频域、时频域及能量4个方面,研究振动压实过程中不同深度填料的动力特性及振动波从振动轮至填料全过程的传播机制。结果表明:振动信号从振动轮至填料的传播过程中,振动加速度峰值近似呈双曲线分布,且与埋深呈反向关系,其传播的临界深度为1.0 m左右;振动信号传播至填料中,基波频率有所增大,基波与各次谐波的幅值则逐渐减小;在任意埋深处,振动信号的基波、1次、2次至5次谐波的幅值呈现指数递减,具有严格的指数函数相关性;Hilbert-Huang变换谱能够全面、系统地反映任意时刻振动信号的时域特征,振动压路机对于填料的有效碾压时间大致为2 s;振动能量主要集中在20~50 Hz频率内,与基波和1次谐波频率基本一致;随着埋深的增加,振动能量逐渐减小,特别是在振动波从振动轮传至填料表面时,振动能量的损耗最为严重。     

Green vehicle technology to enhance the performance of a European port: A simulation model with a cost-benefit approach

In this paper, we study the impact of using a new intelligent vehicle technology on the performance and total cost of a European port, in comparison with existing vehicle systems like trucks. Intelligent autonomous vehicles (IAVs) are a new type of automated guided vehicles (AGVs) with better maneuverability and a special ability to pick up/drop off containers by themselves. To identify the most economical fleet size for each type of vehicle to satisfy the port’s performance target, and also to compare their impact on the performance/cost of container terminals, we developed a discrete-event simulation model to simulate all port activities in micro-level (low-level) details. We also developed a cost model to investigate the present values of using two types of vehicle, given the identified fleet size. Results of using the different types of vehicles are then compared based on the given performance measures such as the quay crane net moves per hour and average total discharging/loading time at berth. Besides successfully identifying the optimal fleet size for each type of vehicle, simulation results reveal two findings: first, even when not utilising their ability to pick up/drop off containers, the IAVs still have similar efficacy to regular trucks thanks to their better maneuverability. Second, enabling IAVs’ ability to pick up/drop off containers significantly improves the port performance. Given the best configuration and fleet size as identified by the simulation, we use the developed cost model to estimate the total cost needed for each type of vehicle to meet the performance target. Finally, we study the performance of the case study port with advanced real-time vehicle dispatching/scheduling and container placement strategies. This study reveals that the case study port can greatly benefit from upgrading its current vehicle dispatching/scheduling strategy to a more advanced one.     

Revenue management in the parking industry: a multiple garage intelligent reservation model

This paper explores how advanced reservations, coupled with dynamic pricing (based on booking limits) can be used to maximize parking revenue. An integer programing formulation that maximizes parking revenue over a system of garages is presented. Furthermore, an intelligent parking reservation model is developed that uses an artificial neural network procedure for online reservation decision-making. Finally, the paper provides some strategic and managerial implications of multi-garage revenue management systems, and discusses techniques for identifying and implementing micro-market segmentation in the parking industry.     

强夯施工质量实时导航技术*!

强夯是最常用和最经济的深层地基处理方法之一,有效地控制强夯施工质量是保证地基稳定与安全的关键。目前,我国强夯施工质量的信息化控制水平较低,主要依靠监理和施工人员人为控制,难以实现对强夯施工质量的精准控制。从强夯施工信息的采集、存储、展示和导航入手,提出一种具有实时、自动、高精度等特点的强夯施工质量实时导航技术,对强夯施工实现实时监测和可视化导航。工程应用表明,本技术满足强夯地基竣工验收一般检测项目的检查要求,对强夯施工过程实现精细控制,提高施工效率和质量。     

南盘江燕子石—甲完恩滩段航道治理

燕子石—甲完恩滩位于龙滩枢纽与平班枢纽的脱水段,现状条件下燕子石滩为一个枯水浅、中水急的险滩,而甲完恩滩则为枯水急滩,无法满足船舶通航要求。基于对滩险的成因和碍航特性的分析,确定了滩险治理思路。经物模和船模多方案优化研究提出推荐方案:燕子石分汊石质急、浅滩整治方案为主、支汊同时开挖,调整汊道分流,平顺航线、拓宽航槽;对于甲完恩滩,疏炸航槽内礁石,扩大卡口断面、拓宽缓流航道。该研究可为山区河流类似河流疑难滩险的整治提供参考。     

A self-learning system for local ramp metering with queue management

This paper presents the design and evaluation process of a self-learning system for local ramp metering control. This system is developed on the basis of reinforcement learning (RL) and can deal with the problem of on-ramp queue management through a continuous learning process. A general framework of the system design including the definition of RL elements and an algorithm that can accomplish the learning process is proposed. Simulation tests are carried out to evaluate the performance of the new system. In terms of the total time spent by road users, the new system can achieve a 30% reduction from the situation of no control, a result which is competitive with the widely accepted algorithm ALINEA. Meanwhile, simulation results show that the new system can keep on-ramp queues strictly under a series of pre-specified constraints, which proves its capability of managing on-ramp queues.     

Required navigation performance for connected and autonomous vehicles: where are we now and where are we going?

ABSTRACT

While automotive original equipment manufacturers and IT companies are developing and demonstrating self-driving cars, true autonomy will not be realised in the near future due in part to the technology readiness level of the existing systems as well as issues of ethics, security, governance and standards surrounding the implementation of autonomy for road transport. However, advances in cellular phones and networks, satellite-based positioning and communications, cloud computing, combined with a rise in the volumes of available data, allied with a reduction in their costs, offer the very real possibility of connecting vehicles, one to another and to smart city infrastructure as part of the Internet of Things (IoT). Data from connected vehicles, when combined with other information, may provide valuable intelligence to traffic managers and other stakeholders via cooperative intelligent transport system (C-ITS) platforms. Nevertheless, many issues face the implementation of a truly connected IoT in general and C-ITS in particular.