A mixed stochastic user equilibrium model considering influence of advanced traveller information systems in degradable transport network

Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.

Sensitivity analysis for stochastic user equilibrium with elastic demand assignment model

This paper puts forward a rigorous approach for a sensitivity analysis of stochastic user equilibrium with the elastic demand （SUEED） model. First, proof is given for the existence of derivatives of output variables with respect to the perturbation parameters for the SUEED model. Then by taking advantage of the gradient-based method for sensitivity analysis of a general nonlinear program, detailed formulae are developed for calculating the derivatives of designed variables with respect to perturbation parameters at the equilibrium state of the SUEED model. This method is not only applicable for a sensitivity analysis of the logit-type SUEED problem, but also for the probit-type SUEED problem. The application of the proposed method in a numerical example shows that the proposed method can be used to approximate the equilibrium link flow solutions for both logit-type SUEED and probit-type SUEED problems when small perturbations are introduced in the input parameters.

Overhanging rock slope by design:An integrated approach using rock mass strength characterisation,large-scale numerical modelling and limit equilibrium methods

Overhanging rock slopes(steeper than 90°) are typically avoided in rock engineering design, particularly where the scale of the slope exceeds the scale of fracturing present in the rock mass. This paper highlights an integrated approach of designing overhanging rock slopes where the relative dimensions of the slope exceed the scale of fracturing and the rock mass failure needs to be considered rather than kinematic release of individual blocks. The key to the method is a simplified limit equilibrium(LE) tool that was used for the support design and analysis of a multi-faceted overhanging rock slope. The overhanging slopes required complex geometries with constantly changing orientations. The overhanging rock varied in height from 30 m to 66 m. Geomechanical modelling combined with discrete fracture network(DFN)representation of the rock mass was used to validate the rock mass strength assumptions and the failure mechanism assumed in the LE model. The advantage of the simplified LE method is that buttress and support design iterations(along with sensitivity analysis of design parameters) can be completed for various cross-sections along the proposed overhanging rock sections in an efficient manner, compared to the more time-intensive, sophisticated methods that were used for the initial validation. The method described presents the development of this design tool and assumptions made for a specific overhanging rock slope design. Other locations will have different geological conditions that can control the potential behaviour of rock slopes, however, the approach presented can be applied as a general guiding design principle for overhanging rock cut slope.

Studying on equilibriums between price and QoS in multi-provider overlay access networks

From the viewpoint of game theory, this paper proposes a model that combines QoS index with price factor in overlay access networks, and uses the multinomial logit （MNL） to model the choice behaviour of users. Each service class is considered an independent and competitive entity offered by each provider, which aims at maximizing its own utility. Based on noncooperative game, we prove the existence and uniqueness of equilibriums between QoS levels and prices among various service classes, and demonstrate the properties of equilibriums. Finally, these results are verified via ntunerieal analysis.

多周期农产品废弃物供应链网络均衡模型构建

目的研究农产品废弃物可持续利用问题,既实现供应链整体利润最优,又减轻对环境的污染。方法在随机需求的背景下,考虑生产合作社对零售商的不同激励度,分析生产合作社、零售商、需求市场的最优状态,利用变分不等式建立相应的多周期供应链网络均衡模型。结果从多周期角度,实现了农产品废弃物供应链网络均衡利益最优化,可为合作社与零售商在较长时间达到一种均衡状态提供有效解决方案。结论既实现了多周期农产品废弃物的持续利用,又促进了循环经济的发展,同时还实现了供应链网络均衡、供应链整体利润最优和减轻环境污染等目标。

基于改进SlowFast模型的设施黄瓜农事行为识别方法

[目的/意义]农事行为活动识别对设施蔬菜生产精准化调控有着重要意义,在一定程度上可以通过查看农事操作的时间、操作过程是否合理来减少因农事行为不当导致产量下降。为了解决农事行为识别方法中由于黄瓜叶片和设施遮挡导致识别准确率不高的问题,提出一种名为SlowFast-SMC-ECA (SlowFast-Spatio-Temporal Excitation、Channel Excitation、Motion Excitation-Efficient Channel Attention)的农事活动行为识别算法。[方法]该算法主要基于SlowFast模型,通过改进Fast Pathway和Slow Pathway中的网络结构来提高对于农事活动中手部动作特征和关键特征的提取能力。在Fast Pathway中,引入多路径激励残差网络的概念,通过在信道之间插入卷积操作来增强它们在时域上的相互关联性,从而更好地捕捉快速运动信息的细微时间变化。在Slow Pathway中,将传统的Residual Block替换为ECA-Res结构,以提高对通道信息的捕获能力。这两项改进有效地加强了通道之间的联系,提升了特征之间的语义信息传递,进而显著提升了农事行为识别的准确率。此外,为了解决数据集中类别不均衡的问题,设计了平衡损失函数(Smoothing Loss),通过引入正则化系数,平衡损失函数可以有效地处理数据集中的类别不均衡情况,提高模型在各个类别上的表现。[结果和讨论]改进的SlowFast-SMC-ECA模型在农事行为识别中表现出良好的性能,各类行为的平均识别精度达到80.47%,相较于原始的SlowFast模型有约3.5%的提升。[结论]本研究在农事行为识别中展现出良好的性能。这对农业生产的智能化管理和决策具有重要意义。

基于软件定义网络的监控流量负载均衡技术研究

负载均衡技术存在平均均衡时延较长的问题,无法满足目前的网络均衡需求,故提出基于软件定义网络的监控流量负载均衡技术。通过软件定义网络设计负载均衡架构,建立监控流量负载均衡模型,优化监控流量链路负载;在硬件设备中,分离数据平面与控制平面,部署多种功能模块,改造子域控制器,并通过单个粒子最优位置的更新迭代,优化网络负载均衡。实验结果表明,设计技术的平均时延小于50 ms,保持在较小范围,表明该技术具有高效性。

传感器网络簇间通信自适应均衡数学模型构建

针对传感器网络簇间通信存在传输信号受外界干扰因素影响严重,码间串扰可能性大,导致信号波形幅度较低,最终影响通信质量的问题,开展传感器网络簇间通信自适应均衡数学模型构建研究。为得到传感器网络中每个节点的不同数据通信半径,划分传感器网络簇间通信节点。对传感器网络中每个簇首节点能耗计算,并设置半径标识码。对通信增益控制校正,并完成动态盲均衡自适应模型建立。通过实例证明,新的数学模型应用下传输信号码间串扰可能性显著降低,信号波形幅度增大,有效促进通信质量的提升。

Component Content Soft-sensor Based on Neural Networks in Rare-earth Countercurrent Extraction Process

Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the error compensation model of fuzzy system,is proposed to solve the prob- lem that the component content in countercurrent rare-earth extraction process is hardly measured on-line.An industry experiment in the extraction Y process by HAB using this hybrid soft-sensor proves its effectiveness.

Component Content Soft-Sensor Based on Hybrid Models in Countercurrent Rare Earth Extraction Process

In consideration of the online measurement of the component content in rare earth countercurrent extraction separation process, the soft sensor method based on hybrid modeling was proposed to measure the rare earth component content. The hybrid models were composed of the extraction equilibrium calculation model and the Radial Basis Function (RBF) Neural Network (NN) error compensation model; the parameters of compensation model were optimized by the hierarchical genetic algorithms (HGA). In addition, application experiment research of this proposed method was carried out in the rare earth separation production process of a corporation. The result shows that this method is effective and can realize online measurement for the component content of rare earth in the countercurrent extraction.

双层规划在城市交通领域研究与应用的系统综述

双层规划是约束条件中含有优化问题,具有上下双层递阶结构的非凸优化问题,是典型的NP-Hard问题。本文系统性综述双层规划在城市交通领域的研究与应用,聚焦交通网络设计和OD(origin destination)反推调整两类问题。首先,利用文献计量法概述国内外研究主题与演变历程。其次,以开创性研究为线索溯源首次系统综述、首篇博士论文、首个TR-B专题和首篇中文综述关键研究。再次,梳理道路、公交、多模式网络设计问题与静态、动态OD反推问题的近期发展。从次,总结通用求解方法,讨论求解方法发展动向,阐述双层规划与平衡约束数学规划的关系。最后,指出未来发展的机遇与挑战:智慧交通探索揭示、建模架构模式优选和计算平台互动共享。

一种改进的粒子群算法在交通分配上的应用

针对粒子群算法收敛速度慢、求解精度低和算法在迭代后期容易陷入局部最优的问题,首先,采用仅以位置项来控制粒子进化方向的简化粒子群算法,以此避免粒子速度过大时导致的粒子发散的现象;其次,引入随迭代次数增加自适应改变的线性惯性权重来消除惯性分量的影响,同时引入莱维飞行策略来改变粒子位置以帮助粒子逃离局部最优;最后,通过四种测试函数对固定权重的粒子群算法、标准粒子群算法和改进算法的性能进行比较。实验证明,改进后的算法在收敛速度、精度和稳定性上都有所提升。在验证了改进算法的有效性后,使用改进后的算法求解单一OD对多路径路网的用户最优模型并与标准粒子群算法求解结果进行对比,改进后的算法求解结果更加稳定均衡,验证了算法的可行性。

高校在线社交网络谣言传播模型

针对高校思想政治工作特点,将在校师生分为无知者、传谣者和智者三类,建立了一类在线社交网络谣言传播模型;应用微分方程定性理论讨论了模型的边界平衡点和正平衡点的局部稳定性,仿真研究了通过控制模型参数达到控制谣言传播的策略.结果表明,只有教师(智者)经常联系学生、及时告知突发事件真相、正确引导学生,并通过网络舆情教育讲座等形式提升学生辨别是非的能力,努力实现“谣言止于智者”,才能有效抑制网络谣言的传播.

基于演化博弈模型的超前点播参与主体策略行为分析

基于超前点播参与主体行为策略演化博弈模型的研究发现,提高点播服务质量进而获得用户正反馈,有利于网络平台超前点播模式的推行;点播平台与用户双方策略行为不因会员权益受影响程度和用户诉讼概率的变化发生改变。建议在保证VIP用户原有权益不受损害的前提下,视频平台要注重提高超前点播增值服务内容质量;超前点播模式的推行要充分考虑用户的反应,以用户为中心。

A projected gradient based game theoretic approach for multi-user power control in cognitive radio network

The fifth generation （5G） networks have been envisioned to support the explosive growth of data demand caused by the increasing traditional high-rate mobile users and the expected rise of interconnections between human and things. To accommodate the ever-growing data traffic with scarce spectrum resources, cognitive radio （CR） is considered a promising technology to improve spectrum utilization. We study the power control problem for secondary users in an underlay CR network. Unlike most existing studies which simplify the problem by considering only a single primary user or channel, we investigate a more realistic scenario where multiple primary users share multiple channels with secondary users. We formulate the power control problem as a non-cooperative game with coupled constraints, where the Pareto optimality and achievable total throughput can be obtained by a Nash equilibrium （NE） solution. To achieve NE of the game, we first propose a projected gradient based dynamic model whose equilibrium points are equivalent to the NE of the original game, and then derive a centralized algorithm to solve the problem. Simulation results show that the convergence and effectiveness of our proposed solution, emphasizing the proposed algorithm, are competitive. Moreover, we demonstrate the robustness of our proposed solution as the network size increases.

停车诱导可变信息标志影响下的多层路网随机用户均衡分配模型

在传统随机用户均衡分配模型基础上,将路网分为路上行驶层、停车巡泊层和步行层3层,用于定量分析停车诱导可变信息标志对驾驶人出行的影响.引入慢速因子体现驾驶人的停车寻找行为,并利用考虑理解误差的费用函数反映停车诱导可变信息标志对驾驶人停车设施选择行为的影响.在此基础上,构建了停车诱导可变信息标志影响下的多层路网随机用户均衡分配模型,并提出了相应的求解算法.算例结果表明,经平均迭代15次模型能较快收敛,当路网上部分道路处于拥堵状态时,停车诱导可变信息标志的设置效果较好,可节约驾驶人6.2%的出行时间.

基于车辆可变折算系数的网络均衡模型及其应用

混合交通流是我国交通流的典型特征。混合交通流中,小汽车和其他类型车辆的交通时间延误是不同的,其折算系数值随道路、交通和车辆类型、运输状态的条件的变化而变化。基于此,应视网络的通行能力为可变通行能力。基于可变通行能力的网络平衡才是更接近实际的网络平衡。以影响网络通行能力的车辆折算系数与各种相关因素关系为基础,给出了可变折算系数下的路段流量,并构建了基于可变车辆折算系数的一个全新的多用户网络均衡分配模型。最后,对温州市域公路网进行实证研究。研究结果表明:基于可变折算系数的多用户交通网络均衡模型比固定折算系数的网络均衡模型更接近实际,更具有实际应用价值。

配电网最大供电能力模型解的性质

从数学角度对配电网最大供电能力(TSC)模型解的性质进行了研究。首先,将TSC模型推导为线性规划模型的一般形式,阐述其数学含义与物理意义。其次,分别给出TSC模型无解与唯一解时参数条件的数学表达式,得到实际配电网的TSC模型总是存在无穷多解的结论。为进一步找出众多解中易于在实际配电网中实现的解,针对TSC解的主变压器负载率均衡度进行分析,总结归纳出达到负载较均衡时的配电网联络与主变压器容量的匹配条件。最后,通过算例验证了结论的有效性。

基于平衡水分模型的稻谷含水率实时监测系统

基于静力学谷物平衡水分模型,利用无线传感器网络及嵌入式技术设计了仓储中稻谷含水率实时监测系统。通过试验验证改进Henderson、改进Chung-Pfost和改进Owin模型及对应参数的稻谷含水率预测误差和精度,结果表明改进Chung-Pfost模型具有准确预测的精度,且当参数A=363.06、B=0.180 4、C=26.674时该模型的预测精度较高。通过测试传感器节点的传输质量,表明系统能够实现数据稳定的传输。