User Equilibrium with Recourse

The focus of this work is to develop a convex mathematical program for static user equilibrium under uncertain link states where users learn the actual state of the arc when they traverse the network and update their route choice in an online manner. The proposed model accounts for one step information where users learn the cost functional form of the links when they reach the upstream node. Two variations of information learning is considered: one where all users reaching a particular node see the same arc states, and another where different users learn different arc states. A convex mathematical programming formulation is proposed and a solution methodology based on the Frank-Wolfe algorithm is provided. Properties of the equilibrium such as existence and uniqueness are discussed. Numerical experiments are conducted on two networks: Nguyen Dupuis and Sioux Falls. Even though the focus of this paper is primarily traffic networks, the fundamental equilibrium model can be applied to other network models where commodities receive information about the state of the network as they traverse the network.     

Arrival Time Reliability in Strategic User Equilibrium

Networks and Spatial Economics - Although traffic assignment models remain heavily utilized globally for the planning and evaluation of new transport infrastructure, commonly applied assignment...     

Stochastic Ridesharing User Equilibrium in Transport Networks

Networks and Spatial Economics - With the development of the Internet and mobile phone technology, it is much easier to access ridesharing information via mobile applications. In this paper, the...     

Second-Order Sensitivity in Applied General Equilibrium

In most policy applications of general equilibrium modeling, cost functions are calibrated to benchmark data. Modelers often choose the functional form for cost functions based on suitability for numerical solution of the model. The data (including elasticities of substitution) determine first and second order derivatives (local behavior) of the cost functions at the benchmark. The functional form implicitly defines third and higher order derivatives (global behavior). In the absence of substantial analytic and computational effort, it is hard to assess the extent to which results of a particular model depend on third and higher order derivatives. Assuming that a modeler has no (or weak) empirical foundation for her choice of functional form in a model, it is therefore a priori unclear to what extent her results are driven by this choice. I present a method for performing second-order sensitivity analysis of modeling results with respect to functional form. As an illustration of this method I examine three general equilibrium models from the literature and demonstrate the extent to which results depend on functional form. The outcomes suggest that modeling results typically do not depend on the functional form for comparative static policy experiments in models with constant returns to scale. This is in contrast to an example with increasing returns to scale and an endogenous steady-state capital stock. Here results move far from benchmark equilibrium and significantly depend on the choice of functional form.     

On the Uniqueness of User Equilibrium Flow with Speed Limit

This technical note focuses on the link flow uniqueness of user equilibrium (UE) with speed limits. Under a mild assumption on the monotonicity of link travel time function, the UE link flow solutions are well recognized to be unique. However, the incorporation of speed limits in the network has undermined the strict monotonicity of link travel time functions, thus the UE flows on the links with speed limits may not be unique. This note addresses the uniqueness problem with two major contributions. First, a polyhedron defined on links is provided, and it is proven that the UE link flow is unique if and only if the polyhedron only contains one value. Second, two concise methods are proposed to mathematically check whether the polyhedron is a singleton, which can be easily solved and convenient for practical use.     

Comparison of Methods for Path Flow Reassignment for Dynamic User Equilibrium

Models to describe or predict of time-varying traffic flows and travel times on road networks are usually referred to as dynamic traffic assignment (DTA) models or dynamic user equilibrium (DUE) models. The most common form of algorithms for DUE consists of iterating between two components namely dynamic network loading (DNL) and path inflow reassignment or route choice. The DNL components in these algorithms have been investigated in many papers but in comparison the path inflow reassignment component has been relatively neglected. In view of that, we investigate various methods for path inflow reassignment that have been used in the literature. We compare them numerically by embedding them in a DUE algorithm and applying the algorithm to solve DUE problems for various simple network scenarios. We find that the choice of inflow reassignment method makes a huge difference to the speed of convergence of the algorithms and, in particular, find that ??travel time responsive?? reassignment methods converge much faster than the other methods. We also investigate how speed of convergence is affected by the extent of congestion on the network, by higher demand or lower capacity. There appears to be much scope for further improving path inflow reassignment methods.     

Capturing Design Space From a User Perspective: The Repertory Grid Technique Revisited

The design of an artifact (e.g., software system, household appliance) requires a multitude of decisions. In the course of narrowing down the design process, "good ideas" have to be divided from "bad ideas." To accomplish this, user perceptions and evaluations are of great value. The individual way people perceive and evaluate a set of prototypes designed in parallel may shed light on their general needs and concerns. The Repertory Grid Technique (RGT) is a method of elucidating the so-called personal constructs (e.g., friendly-hostile, bad-good, playful-expert-like) people employ when confronted with other individuals, events, or artifacts. We assume that the personal constructs (and the underlying topics) generated as a reaction to a set of artifacts mark the artifacts' design space from a user's perspective and that this information may be helpful in separating valuable ideas from the not so valuable. This article explores the practical value of the RGT in gathering design-relevant information about the design space of early artifact prototypes designed in parallel. Ways of treating the information gathered, its quality and general advantages, and limitations of the RGT are presented and discussed. In general, the RGT proved to be a valuable tool in exploring a set of artifact's design space from a user's perspective.     

Path-Based Dynamic User Equilibrium Model with Applications to Strategic Transportation Planning

Networks and Spatial Economics - This study proposes an analytical capacity constrained dynamic traffic assignment (DTA) model along with an efficient path-based algorithm. The model can be applied...     

Computing Dynamic User Equilibrium on Large-Scale Networks Without Knowing Global Parameters

Networks and Spatial Economics - Dynamic user equilibrium (DUE) is a Nash-like solution concept describing an equilibrium in dynamic traffic systems over a fixed planning period. DUE is a...     

Inefficiency of Logit-Based Stochastic User Equilibrium in a Traffic Network Under ATIS

This paper makes a contribution to the literature by bounding the travel time inefficiency of the logit-based stochastic user equilibrium (SUE) under Advanced Traveler Information Systems (ATIS). All drivers are divided into two groups, one equipped with ATIS and another without, and both of which follow the logit-based SUE principle in making route choices. The equipped drivers have less degree of travel time variability than the unequipped ones. The inefficiency of the two-user class SUE is defined in two different ways, i.e., in comparison with the SO in terms of total actual system travel time, or in comparison with the corresponding SSO in terms of total perceptive system travel time of all users. The effects of various parameters on the bounds are further investigated. It is found that the inefficiency bound against the SSO is only dependent upon the degree of link congestion and independent of the network topology. In contrast, besides the effect of the degree of link congestion, the increasing of total demand and network complexity will also make the inefficiency bound against the SO go up, while the promotion of ATIS market penetration and perception benefit will reduce the bound.     

基于用户浏览行为分析的用户兴趣获取

从用户的浏览行为可以反映用户的兴趣出发,分析了用户的浏览行为与兴趣之间的关系,提出了五种用户最小浏览行为组合,并在此基础上对其中三种行为进行转化,得到影响用户兴趣的关键的两种行为,并给出这两种行为与用户兴趣度之间的定量关系。结合对网页内容的挖掘,获取用户的兴趣。通过实验对文中的研究结果进行验证,实验结果证明,所采用的方法是合理和有效的,分析出的用户兴趣基本上可以正确反映用户的实际兴趣。     

基于用户浏览行为分析的用户兴趣获取

从用户的浏览行为可以反映用户的兴趣出发,分析了用户的浏览行为与兴趣之间的关系,提出了五种用户最小浏览行为组合,并在此基础上对其中三种行为进行转化,得到影响用户兴趣的关键的两种行为,并给出这两种行为与用户兴趣度之间的定量关系.结合对网页内容的挖掘,获取用户的兴趣.通过实验对文中的研究结果进行验证,实验结果证明,所采用的方法是合理和有效的,分析出的用户兴趣基本上可以正确反映用户的实际兴趣.     

用户行为数据分析平台用户竞品分析及相关探究

随着大数据时代的快速发展,数据决策在电商、医疗卫生、交通运输等行业发挥了极为重要的作用,并衍生出许多数据分析平台。其中,用户行为数据分析平台是专门分析用户浏览网页、操作事件时留下的海量信息,从而获得用户行为特征的平台,以此推动企业的不断发展。笔者从数据采集功能、数据分析功能、数据导出方式、辅助功能和盈利模式五部分出发,对现有用户行为数据分析平台展开竞品分析及相关探究。     

Dynamic User Equilibrium Model for Combined Activity-Travel Choices Using Activity-Travel Supernetwork Representation

Integrated urban transportation models have several benefits over sequential models including consistent solutions, quicker convergence, and more realistic representation of behavior. Static models have been integrated using the concept of Supernetworks. However integrated dynamic transport models are less common. In this paper, activity location, time of participation, duration, and route choice decisions are jointly modeled in a single unified dynamic framework referred to as Activity-Travel Networks (ATNs). ATNs is a type of Supernetwork where virtual links representing activity choices are added to augment the travel network to represent additional choice dimensions. Each route in the augmented network represents a set of travel and activity arcs. Therefore, choosing a route is analogous to choosing an activity location, duration, time of participation, and travel route. A cell-based transmission model (CTM) is embedded to capture the traffic flow dynamics. The dynamic user equilibrium (DUE) behavior requires that all used routes (activity-travel sequences) provide equal and greater utility compared to unused routes. An equivalent variational inequality problem is obtained. A solution method based on route-swapping algorithm is tested on a hypothetical network under different demand levels and parameter assumptions.     

基于用户行为的长查询用户满意度分析

搜索引擎性能评估是信息检索界一个重要课题.长查询具有较为丰富的信息内容,能更加准确地描述用户的信息需求.在此基础上文中提出长查询用户满意度分析的整体框架,定义用户满意度的概念,并在用户日志中提取相关用户行为特征,应用决策树和SVM两种分类算法评测用户满意度.在大规模商业搜索引擎日志上完成的实验结果证明了这套评价体系的有效性.结果表明,用户对于查询满意和不满意的分类准确率分别达到86％和70％.     

Divergence-Free Wavelet Analysis of Turbulent Flows

In this paper we study the application of divergence-free wavelet bases for the analysis of incompressible turbulent flows and perform several experiments. In particular, we analyze various nominally incompressible fields and study the influence of compressible perturbations due to experimental and computational errors. In addition, we investigate the multiscale structure of modes obtained from the Proper Orthogonal Decomposition (POD) method. Finally, we study the divergence-free wavelet compression of turbulent flow data and present results on the energy recovery. Moreover, we utilize wavelet decompositions to investigate the regularity of turbulent flow fields in certain non-classical function spaces, namely Besov spaces. In our experiments, we have observed significantly higher Besov regularity than Sobolev regularity, which indicates the potential for adaptive numerical simulations.     

Propagation of Data Error and Parametric Sensitivity in Computable General Equilibrium Models

While computable general equilibrium (CGE) models are a well-established tool in economic analyses, it is often difficult to disentangle the effects of policies of interest from that of the assumptions made regarding the underlying calibration data and model parameters. To characterize the behavior of a CGE model of carbon output with respect to two of these assumptions, we perform a large-scale Monte Carlo experiment to examine its sensitivity to base year calibration data and elasticity of substitution parameters in the absence of a policy change. By examining a variety of output variables at different levels of economic and geographic aggregation, we assess how these forms of uncertainty impact the conclusions that can be drawn from the model simulations. We find greater sensitivity to uncertainty in the elasticity of substitution parameters than to uncertainty in the base-year data as the projection period increases. While many model simulations were conducted to generate large output samples, we find that few are required to capture the mean model response of the variables tested. However, characterizing standard errors and empirical probability distribution functions is not possible without a large number of simulations.     

有线电视用户行为分析实践

以有线电视网用户行为数据（东方有线2013年第一季度）为基础,实现了用户行为分析的典型应用——个性化节目推荐。实践过程中应用互联网数据处理的大数据技术,包括构建了大数据平台,实现生产大数据的流程,采用SlopeOne和item-to-item算法实现了用户行为分析的典型应用——个性化节目推荐。     

A Study on Network Design Problems for Multi-modal Networks by Probit-based Stochastic User Equilibrium

This paper develops a multi-modal transport network model considering various travel modes including railway, bus, auto, and walking. Travellers are assumed to choose their multi-modal routes so as to minimise their perceived disutilities of travel following the Probit Stochastic User Equilibrium (SUE) condition. Factors influencing the disutility of a multi-modal route include actual travel times, discomfort on transit systems, expected waiting times, fares, and constants specific to transport modes. The paper then deals with the multi-modal network design problem (NDP). The paper employs the method of sensitivity analysis to define linear approximation functions between the Probit SUE link flows and the design parameters, which are then used as constraints in the sub-problem of the NDP instead of the original SUE condition. Based on this reformulated NDP, an efficient algorithm for solving the problem is proposed in the paper. Two instances of this general NDP formulation are then presented in the paper: the optimal frequency design problem for public transport services (FDP), and the anti-freezing admixture dispersion problem (AADP).