Equity based land‐use and transportation problem

Due to additional trip production by land use development, the O‐D travel costs between some O‐D pairs may also change intuitively. This leads to positive and negative impacts on network users traveling between different O‐D pairs. Therefore the equity issue about the benefit distribution gained from the land‐use development problem is raised. This paper proposes an Equity based Land‐Use Transportation Problem (ELUTP) which is intended to examine the benefit distribution among the network users and the resulting equity associated with land‐use development problem in terms of the change of equilibrium O‐D travel cost. In the resulting bi‐level programming model, the upper level sub‐problem maximizes traffic production incorporating equity constraints, while the lower level sub‐problem is a combined trip distribution/assignment user equilibrium problem. Genetic algorithm based method is applied to test the models using an example network.     

加强技术创新产品开发实现跨越式发展

２０００年７月３日，长春汽车研究所建成５０周年，５０年来，研究所始终坚持技术进步，不断创新，使产品开发实现了跨越式发展，为一汽产品一直保持高的市场竞争力奠定了坚实的技术基础，介绍了一汽产品的更新换代情况、ＣＡＤ／ＣＡＥ／ＣＡＭ一体化进程及产品试验手段、试制技术的扩展与提高情况。     

Active regulation of battery charge-sustaining in ECMS: Application in energy management for engine waste heat recovery system

Equivalent consumption minimization strategy (ECMS) is a widely used energy management method in the battery equipped bio-sources energy system, in which an equivalence factor is adopted to weigh the two kinds of energy, usually fuel and electricity. The regulation of the equivalence factor will affect not only the fuel consumption but also the battery's state of charge (SOC) sustainability, which results great influence upon the energy management of the system. In this paper, a new perspective of treating the relationship between the equivalence factor and instantaneous fuel consumption as well as instantaneous electricity consumption as a first-order dynamic system is proposed, thus the relationship between the equivalence factor and SOC is deduced as a second-order dynamic system. Based on the perspective, a linear second-order Active Disturbance Rejection Control (ADRC) is employed to regulate the equivalence factor, which can estimate and compensate, in real-time, disturbances in the system from input-output information only. An engine waste heat recovery energy network constructed by <engine> - <power turbine> - <Organic Rankine Cycle System> - <electric cooling system> - <battery> - <Integrated starter and Generator> is selected as the research object, simulation verifications upon 11 different driving cycles based on the simulation platform established by GT-SUITE software are conducted to test the fuel-saving capability and SOC self-sustainability by the proposed approach with a same set of tuning parameters. Simulation results indicate that both the fuel-saving capability and the SOC self-sustainability can be ensured by the active control of equivalent factor with a same set of tuning parameters upon all the 11 driving cycles, demonstrating a great adaptability of the control parameters.     

Importance of traveler attitudes in the choice of public transportation to work: findings from the Regional Transportation Authority Attitudinal Survey

The commute mode choice decision is one of the most fundamental aspects of daily travel. Although initial research in this area was limited to explaining mode choice behavior as a function of traveler socioeconomics, travel times, and costs, subsequent studies have included the effect of traveler attitudes and perceptions. This paper extends the existing body of literature by examining public transit choice in the Chicago area. Data from a recent Attitudinal Survey conducted by the Regional Transportation Authority (RTA) in Northeastern Illinois were used to pursue three major steps. First, a factor analysis methodology was used to condense scores on 23 statements related to daily travel into six factors. Second, the factor scores on these six dimensions were used in conjunction with traveler socioeconomics, travel times, and costs to estimate a binary logistic regression of public transit choice. Third, elasticities of transit choice to the six factors were computed, and the factors were ranked in decreasing order of these elasticities. The analysis provided two major findings. First, from a statistical standpoint, the attitudinal factors improved the intuitiveness and goodness-of-fit of the model. Second, from a policy standpoint, the analysis indicated the importance of word-of-mouth publicity in attracting new riders, as well as the need for a marketing message that emphasizes the lower stress level and better commute time productivity due to transit use.     

Dynamic system‐optimal traffic assignment for a city using the continuum modeling approach

This paper presents a continuum dynamic traffic assignment model for a city in which the total cost of the traffic system is minimized: the travelers in the system are organized to choose the route to their destinations that minimizes the total cost of the system. Combined with the objective function, which defines the total cost and constraints such as certain physical and boundary conditions, a continuum model can be formulated as an optimization scheme with a feasible region in the function space. To obtain an admissible locally optimal solution to this problem, we first reformulate the optimization in discrete form and then introduce a heuristic method to solve it. This method converges rapidly with attractive computational cost. Numerical examples are used to demonstrate the effectiveness of the method. Copyright © 2013 John Wiley & Sons, Ltd.     

Identifying the most critical transportation intersections using social network analysis

Traffic congestion negatively impacts our society. Most of the traditional transportation planning techniques – though effective – require rigorous amounts of data and analysis which consumes time and resources. This paper uses social network analysis (SNA) to analyze transportation networks, and consequently corroborate the effectiveness of SNA as a complementary tool for improved transportation planning. After creating the connection between the language and concepts of SNA and those of transportation systems – as well as developing a model that utilizes different SNA centrality measures within the transportation context – the authors utilize SNA to investigate traffic networks in three case studies in the state of Louisiana, analyze the results and draw conclusions. To this effect, with minimal cost and time, the model identifies the most critical intersections that should be further investigated using traditional techniques. These results are in agreement with the findings of Louisiana’s Department of Transportation and Development.     

Application of time series techniques for forecasting truck traffic attracted by the Bombay metropolitan region

Knowledge of future traffic flow is an essential input in the planning, implementation and development of a transportation system. It also helps in its operation, management and control. Time series analysis techniques have been extensively adopted for this purpose in the fields of economics, social sciences and in other fields of technology. An attempt has been made in this study to apply the techniques of time series analysis to goods traffic, particularly truck traffic. Four predominant corridors, N.H.3, N.H.4, N.H.8 and Lal Bahadur Shastri Road (L.B. S. Rd.), accounting for majority of truck movement in the Bombay Metropolitan Region (BMR), have been considered for modeling. Raw data was processed initially, to obtain an insight into the structure of time series. Ten candidate models of the Auto-Regressive Moving Average (ARMA) and Auto-Regressive Integrated Moving Average (ARIMA) family are investigated to represent each of the four corridors. Models finally proposed, to represent each of the four corridors have been selected based on Minimum Mean Square Error (MMSE) and Maximum Likelihood Rule (MLR) criteria. Models ARIMA (2, 1, 0), ARMA (1.0), ARMA (1, 1) and ARIMA (1, 1, 0) are proposed for N.H.3, N.H.4, N.H.8 and L.B.S. Rd. respectively, based on significant weekly periodicity.     

浆体管道输送临界流速的影响因素及计算分析

临界流速是浆体管道输送的一个重要因素 ,目前尚无普遍的使用公式。例如杜兰德 (Du rand)、格拉弗 (Draf)、托马斯 (Thomas)等考虑的因素少 ,而且还需要特定的条件。在前人试验研究的基础上 ,找出影响浆体管道临界流速的主要因素并进行分析 ,再利用尖山铁精矿管道输送试验数据的实测值与计算值进行比较 ,找出一个比较适合管道输送的普遍临界流速公式。     

Walking infrastructure design assessment by continuous space dynamic assignment modeling

For the planning and design of walking infrastructure, characterized by the fact that the pedestrians can choose their paths freely in two‐dimensional space, applicability of traditional discrete network models is limited. This contribution puts forward an approach for user‐optimal dynamic assignment in continuous time and space for analyzing for instance walking infrastructure in a two‐dimensional space. Contrary to network‐based approaches, the theory allows the traffic units to choose from an infinite non‐countable set of paths through the considered space. The approach first determines the continuous paths using a path choice model. Then, origin‐destination flows are assigned and traffic conditions are calculated. The approach to determine a user‐optimal assignment is heuristic and consists of a sequence of all‐or‐nothing assignments. An application example is presented, showing dynamic user equilibrium traffic flows through a realistic transfer station. The example is aimed at illustrating the dynamic aspects of the modeling approach, such as anticipation on expected flow conditions, and predicted behavior upon catching or missing a connection.