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An Analysis on Efficiency and Equity of Fixed-Time Ramp Metering  [PDF]
Ali Sercan Kesten, Murat Ergün, Tetsuo Yai
Journal of Transportation Technologies (JTTs) , 2013, DOI: 10.4236/jtts.2013.32A006

Various traffic management strategies have been developed to alleviate the congestion on freeways. The equity issue has been considered as one of the major challenges for the implementation of some traffic control strategies, especially ramp metering. This paper presents a comparative evaluation of the efficiency and equity performance of a traffic control strategies namely Fixed Time Ramp Metering (FTRM). Instead of focusing on a single equity measure and/or indicator, different approaches to the equity concept are discussed and various equity measures are examined. The equity and efficiency performance of traffic control strategies are compared and evaluated by incorporating them into the simulated corridor. The Bosporus Bridge of Istanbul O-1 Freeway, Turkey is used as a test-bed for the simulation model and the control strategy is employed through microscopic traffic flow simulation software, VISSIM AG. The findings from the simulations show that the equity and efficiency properties of the network vary with the measures and indicators taken into account. The results also suggest that the trade-off between equity and efficiency can be observed for some measures, whereas regarding to other measures the trade-off is not validated.

Freeway ramp metering control made easy and efficient  [PDF]
Hassane Abouaissa,Michel Fliess,Violina Iordanova,Cédric Join
Mathematics , 2012,
Abstract: "Model-free" control and the related "intelligent" proportional-integral (PI) controllers are successfully applied to freeway ramp metering control. Implementing moreover the corresponding control strategy is straightforward. Numerical simulations on the other hand need the identification of quite complex quantities like the free flow sp\^eed and the critical density. This is achieved thanks to new estimation techniques where the differentiation of noisy signals plays a key r\^ole. Several excellent computer simulations are provided and analyzed.
Reinforcement Learning Ramp Metering without Complete Information
Xing-Ju Wang,Xiao-Ming Xi,Gui-Feng Gao
Journal of Control Science and Engineering , 2012, DOI: 10.1155/2012/208456
Abstract: This paper develops a model of reinforcement learning ramp metering (RLRM) without complete information, which is applied to alleviate traffic congestions on ramps. RLRM consists of prediction tools depending on traffic flow simulation and optimal choice model based on reinforcement learning theories. Moreover, it is also a dynamic process with abilities of automaticity, memory and performance feedback. Numerical cases are given in this study to demonstrate RLRM such as calculating outflow rate, density, average speed, and travel time compared to no control and fixed-time control. Results indicate that the greater is the inflow, the more is the effect. In addition, the stability of RLRM is better than fixed-time control.
Coordinated control of variable speed limits and ramp metering

WANG Zheng-wu,LUO Da-yong,HUANG Zhong-xiang,

控制理论与应用 , 2007,
Abstract: In order to alleviate or eliminate congestion on a freeway, the dynamic traffic control measures, such as speed limits and ramp metering, are usually adopted. Because the control strategies of speed limits and ramp metering, obtained by optimization separately, may be inconsistent, it is necessary to coordinate speed limits and ramp metering. Unfortunately, there is no effective way to build and solve coordinated control model of speed limits and ramp metering. Based on macroscopic traffic flows theory and multi-agent methods, coordinated control model of speed limits and ramp metering is proposed in this paper. Firstly, a macroscopic traffic flows model of freeway is briefly introduced. Secondly, a speed limit-metering traffic flows model is suggested after traffic characteristic of speed limits and ramp metering is analyzed. Thirdly, coordinated control model of speed limits and ramp metering is proposed and solved based on the multi-agent methods and hierarchical structure. Finally, an example to control simulation freeway is given to illustrate the construction approach.
Off-Ramp Control near Surface Road  [cached]
Yulong Pei,Kan Zhou
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: To enhance the overall performance of operation of urban expressway, a ramp metering control strategy is proposed to delays and queues of vehicle platoon along off-ramp near the surface road. This control mode measures the real time traffic conditions at off ramps through the derived occupancy data and then optimizes the green time and length of cycle. A Vissim based simulation analysis is used to verify the effectiveness of this proposed control strategy using the field data of Zhuque Bridge and Taoyuan Bridge of South 2 Ring Road in Xi’an city. The simulation results show that the traffic flows can be allocated homogeneously, even during the peak hours and the average traveling time and platoon queue can be reduced approximate 5~7%, compared with the simulated findings of no control mode and fixed time control mode.
Model Free Adaptive Control Based Freeway Ramp Metering with Feedforward Iterative Learning Controller

HOU Zhong-Sheng YAN Jing-WenAdvanced Control Systems Laboratory of School of Electronics,Information Engineering,Beijing Jiaotong University,Beijing,

自动化学报 , 2009,
Abstract: In this work, a novel model-free adaptive control based freeway ramp metering strategy with feedforward iterative learning is proposed. The modularized controller design with feedforward iterative learning controller added on to the feedback model free adaptive control (MFAC) controller makes use of the periodicity of the traffic flow effectively and improves the controller performance greatly. With rigorous analysis, the proposed control scheme guarantees the asymptotic convergences along the iteration axis. Intensive simulations show the effectiveness of the proposed strategy.
A Model-free Periodic Adaptive Control for Freeway Traffic Density via Ramp Metering

CHI Rong-Hu,HOU Zhong-Sheng,

自动化学报 , 2010,
Abstract: In this paper, a novel model-free periodic adaptive ramp metering scheme is presented for a freeway traffic system, which can be formulated as a general MIMO nonlinear system. The proposed method is model-free in nature, and the control inputs and the pseudo Jacobi parameters are updated periodically in a pointwise manner over the entire period, by directly using the I/O data obtained in the preceding periods. The geometrical tracking performance is shown with rigorous analysis. The simulation results illustrate the validity of the proposed method.
Comparison of metering mechanisms of corn seed
Weirich Neto, Pedro H.;Justino, Altair;Namur, Rodrigo T.;Domingues, José;Garcia, Luiz C.;
Engenharia Agrícola , 2012, DOI: 10.1590/S0100-69162012000500017
Abstract: it was compared the performance of the metering mechanism of corn seeds (zea mays) in direct seeding in an area of ??200 ha, a property in piraí do sul, state of paraná - pr, in brazil. it was seeded 4 maize hybrids, 50 ha of each, with seeds of different sieves. the experiment was conducted in a randomized block design (rbd), with 3 treatments and 9 repetitions for each corn hybrid. the treatments were the pneumatic seed of metering mechanisms, horizontal perforated disc with and without ramp?. the plots were 40 m2 and were distributed at the early, middle and late sowing. the variables analyzed in each corn hybrid were initial population, faulty spacing, multiple spacing, acceptable spacing, and yield components. as there were no significant differences in the variables, it was concluded that the quality of seeding with different systems of distribution was similar in the different sieves of distributed corn seeds.
Nonlinear feedback ramp controller in freeway based on fuzzy logic

LIANG Xin-rong,LIU Zhi-yong,MAO Zong-yuan,

控制理论与应用 , 2006,
Abstract: The on-ramp control is considered as an important component of freeway traffic control and intelligent transport systems,but the results of existing on-ramp control are not satisfactory.A nonlinear feedback method is proposed for on-ramp metering by using fuzzy logic.The freeway traffic flow dynamic model is built.Based on the model and in conjunction with the fuzzy logic theory,the nonlinear feedback ramp controller is designed. The ramp metering rate is determined by the fuzzy control based on the density tracking error and error variation.Triangle curves are used for the membership functions of the fuzzy variables.The rule base including 56 fuzzy rules is also established.Finally,the control system is simulated in MATLAB software.The result shows that the controller designed has good dynamic and steady-state performance,and can achieve a desired traffic density along the mainline of a freeway.This method is effective to the on-ramp control.
Security and Privacy-Preserving Metering Service in the Smart Grid  [PDF]
Zhongwei Sun, Chuqi Song
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.108B033
The deployment of smart metering provides an immense amount of data for power grid operators and energy providers. By using this data, a more efficient and flexible power grid can be realized. However, this data also raises privacy concerns since it contains very sensitive information about customers. In this paper, we present a security and privacy-preserving metering scheme for the community customers, by utilizing the password authenticated key exchange (PAKE) protocol and Elliptic Curve Cryptosystem (ECC). The proposed scheme will protect the community network from possible malicious behavior, and security analysis is also given in the paper.
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