A Hybrid TCNN Optimization Approach for the Capacity Vehicle Routing Problem

Introduction The vehicle routing problem(VRP)is one ofthe well-known NP-hard optimization problems[1]occurring in many transport logistics and distribu-tion systems of considerable economic significance.The capacity vehicle routing problem(CVRP)likeVRP with the additional constraint that every vehi-cle must have a capacity,so it is also an NP-hardoptimization problems.It involves minimizing costvehicle schedules for a fleet of vehicles originatingand terminating from a central depot.The …     

斜拉桥设计中拉索抗风问题研究综述

随着大跨斜拉桥的频繁建造,斜拉索抗风问题日益突出。大跨斜拉桥中系统进行拉索抗风研究的工程实例较少,研究中尚有许多需要解决的问题。该文归纳总结了斜拉索的风振控制、风阻系数,并提出了抗风研究展望,可供斜拉桥设计者和斜拉索抗风研究者参考。     

A note on a provable secure encryption scheme

A Cramer-Shoup scheme was modified in a variant way.The major advantage with respect to Kurosawa-Desmedt scheme is that it saves a key parameter and produces shorter ciphertext.The proof of security shows that our scheme can be instantiated with any computational secure key derivation and message authentication functions.Thus it extends the applicability of the Kurosawa-Desmedt scheme and improves its effciency.     

Development of fuel cell hybrid powertrain research platform based on dynamic testbed

An experimental research platform based on a dynamic testbed is developed and applied for fuel cell hybrid powertrain integration and control. A driver brake model is added to the dynamic testbed to simulate the braking process of an electric vehicle. Sub-systems of the fuel cell hybrid powertrain are tested, and characteristic parameters are obtained. A simulation platform is constructed in LabVIEW environment, and its validity is verified by dynamic test results. A real time control system is developed with an embedded PC for the function of rapid control prototyping. Using this platform, fuel cell battery hybrid and fuel cell supercapacitor hybrid configurations are investigated. This platform provides a powerful tool for fuel cell powertrain research and development.     

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为了更精确地预测短期交通流,提出由季节自回归求和移动平均模型(SARIMA)和广义回归神经网络(GRNN)模型所构成的组合模型(SARIMA-GRNN模型),该模型结合了时间序列模型和神经网络模型进行时间序列预测的优点。构造该组合模型的两个组成模型,即SARIMA模型和GRNN模型,也被用于预测研究以便于验证该组合模型在预测上的优势。实证研究结果表明,组合模型的预测精度高于SARIMA模型,但是却并不必然高于GRNN模型。然而,合理选择组合模型中神经网络部分的输入变量以及输出变量将显著地改善模型的预测精度,本文所构造的这个组合模型不仅具有很好的预测表现而且结构简单,非常适合城市道路短期交通流的实时预测。     

波浪荷载作用下施工平台随机动力响应分析

以青岛海湾大桥海上施工平台为背景,采用有限元分析程序提取了平台的各阶自振频率。对随机波浪作用下考虑不同激励方向的动力响应进行计算,并分析了不同激励方向对结构随机响应的影响,得出波浪荷载以45°方向激励时,结构以扭转为主的振型得到发挥,动力响应出现两次峰值。通过施工平台静、动力计算结果的比较,建议在施工平台的设计时,应充分考虑到波浪力的动力效应。     

高墩深水大跨度连续刚构桥非一致地震响应分析

讨论了高墩深水大跨度连续刚构桥的地震响应分析。提出一种适用于计算深水桥墩的地震动水压力公式,在有限元模型中采用附加质量的方法计入该作用,并考虑非一致激励和桩土耦合对桥梁结构的作用,并对不考虑动水压力和考虑动水压力工况进行比较。分析表明,考虑动水压力时的地震反应内力和位移比不考虑动水压力时的地震反应内力和位移大。分析结果可以为连续刚构桥的抗震设计提供参考。     

舰船大容量变压器励磁涌流的故障识别

舰船电力系统已经逐步由传统的低压电力系统过渡到中压电力系统,变压器在舰船电力系统中地位和作用也日益凸现,对变压器的保护也日益重要,尤其是在发生短路故障时,迅速可靠的跳闸,是保证变压器安全的重要手段。大容量变压器的内部短路故障主要依靠差动保护,而励磁涌流往往会引起差动保护误动作,因此如何快速识别励磁涌流是确保变压器安全可靠的前提条件。     

燃料电池锂电池混合动力船舶建模与仿真

全电动绿色船舶除了使用电力,还越来越多地采用替代能源,如燃料电池、太阳能电池等。本文建立船舶混合动力推进系统,采用燃料电池和锂电池并联作为混合动力。在功率不足时,锂电池提供额外的功率以满足负载需求。为了模型比较贴合实际,使用真实数据对混合动力系统的子部件进行建模,生成Simulink模型并进行仿真。     

Dynamic force profile in hydraulic hybrid vehicles: a numerical investigation

A hybrid hydraulic vehicle (HHV) combines a hydraulic sub-system with the conventional drivetrain in order to improve fuel economy for heavy vehicles. The added hydraulic module manages the storage and release of fluid power necessary to assist the motion of the vehicle. The power collected by a pump/motor (P/M) from the regenerative braking phase is stored in a high-pressure accumulator and then released by the P/M to the driveshaft during the acceleration phase. This technology is effective in significantly improving fuel-economy for heavy-class vehicles with frequent stop-and-go drive schedules. Despite improved fuel economy and higher vehicle acceleration, noise and vibrations are one of the main problems of these vehicles.

The dual function P/Ms are the main source of noise and vibration in a HHV. This study investigates the dynamics of a P/M and particularly the profile and frequency-dependence of the dynamic forces generated by a bent-axis P/M unit. To this end, the fluid dynamics side of the problem has been simplified for investigating the system from a dynamics perspective. A mathematical model of a bent axis P/M has been developed to investigate the cause of vibration and noise in HHVs. The forces are calculated in time and frequency domains. The results of this work can be used to study the vibration response of the chassis and to design effective vibration isolation systems for HHVs.