scholarly journals RSU LOCALIZATION MODEL AND SIMULATION OPTIMIZATION FOR VII NETWORK

Transport ◽  
2012 ◽  
Vol 26 (4) ◽  
pp. 394-402 ◽  
Author(s):  
Jian Sun ◽  
Yuwei Yang
Keyword(s):  
Penetration Rate ◽  
Traffic Monitoring ◽  
Simulation Software ◽  
Traffic Information ◽  
Market Penetration ◽  
Test Bed ◽  
Evaluation Measures ◽  
Localization Model ◽  
Component Object ◽  
The Impact

While facing the needs for Vehicle Infrastructure Integration (VII) applications in traffic management, the paper deals with the problem of locating Road Side Units (RSU) for VII deployment. After analyzing the difference between traditional problems of locating traffic information detector and the problem of RSU location, a significance ranking model for RSU localization and three kinds of Significance Degree (SD) computing strategies are put forward. A VII simulation environment for the purpose of RSU localization optimization within VISSIM microscopic traffic simulation software is established developing add-on functions using VISSIM's Component Object Model (COM). A VII test bed of the Olympic Park network in Beijing is taken as an example to evaluate the performance of RSU localization model. The results of simulation experiments indicate that the mixed SD strategy considering both speed and route monitoring is superior to the other two SD strategies. Then, the impact of RSU number and OBE market penetration rate on the evaluation measures of traffic monitoring are studied with reference to the proposed mixed SD strategy. In this case, the evaluation measures of optimized RSU configurations generated by the ranking algorithm are always better than those of random RSU configurations. In addition, the benefits of optimized RSU configurations increase along with RSU number and market penetration rate while the benefits of random RSU configurations are more fluctuant.

scholarly journals High-Resolution Traffic Sensing with Probe Autonomous Vehicles: A Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 464
Author(s):  
Wei Ma ◽  
Sean Qian
Keyword(s):  
High Resolution ◽  
Autonomous Vehicles ◽  
Penetration Rate ◽  
Data Driven ◽  
Traffic Information ◽  
Flow Density ◽  
Massive Data ◽  
Market Penetration ◽  
High Resolution Data ◽  
Data Driven Approach

Recent decades have witnessed the breakthrough of autonomous vehicles (AVs), and the sensing capabilities of AVs have been dramatically improved. Various sensors installed on AVs will be collecting massive data and perceiving the surrounding traffic continuously. In fact, a fleet of AVs can serve as floating (or probe) sensors, which can be utilized to infer traffic information while cruising around the roadway networks. Unlike conventional traffic sensing methods relying on fixed location sensors or moving sensors that acquire only the information of their carrying vehicle, this paper leverages data from AVs carrying sensors for not only the information of the AVs, but also the characteristics of the surrounding traffic. A high-resolution data-driven traffic sensing framework is proposed, which estimates the fundamental traffic state characteristics, namely, flow, density and speed in high spatio-temporal resolutions and of each lane on a general road, and it is developed under different levels of AV perception capabilities and for any AV market penetration rate. Experimental results show that the proposed method achieves high accuracy even with a low AV market penetration rate. This study would help policymakers and private sectors (e.g., Waymo) to understand the values of massive data collected by AVs in traffic operation and management.

Safety Evaluation of the Advanced Stop Assist System in Connected Vehicle Environment

2018 ◽  
Vol 2672 (22) ◽  
pp. 47-57 ◽  
Author(s):  
Gwamaka Njobelo ◽  
Thobias Sando ◽  
Soheil Sajjadi ◽  
Enock Mtoi ◽  
Eren Erman Ozguven ◽  
...  
Keyword(s):  
Safety Evaluation ◽  
Signalized Intersections ◽  
Simulation Software ◽  
Sensitivity Analyses ◽  
Dominant Factor ◽  
Connected Vehicle ◽  
Market Penetration ◽  
Test Bed ◽  
Dilemma Zone ◽  
Advisory Speed

Although traffic signals are installed to reduce the overall number of collisions at intersections, certain types, in particular, rear-end collisions are increasing due to signalization. One dominant factor associated with rear-end crashes is the indecisiveness of the driver, especially in the dilemma zone. An advisory system to help the driver make the stop-or-pass decision would greatly improve intersection safety. This study proposes and evaluates an Advanced Stop Assist System (ASAS) at signalized intersections by using Vehicle-to-Infrastructure (V2I) communication. The proposed system utilizes communication data, received from roadside equipment, to provide approaching vehicles with vehicle-specific advisory speed messages to prevent vehicle hard-braking at a yellow or red signal. A simulation test bed was modeled using VISSIM, a microscopic simulation software, to evaluate the effectiveness of the proposed system. The results demonstrate that at full market penetration (100% saturation of vehicles equipped with on-board communication equipment), the proposed system reduces the number of hard-braking vehicles by nearly 50%. Sensitivity analyses of market penetration rates also show a degradation in safety conditions at penetration rates lower than 40%. The results suggest that a penetration rate of at least 60% is required for the proposed system to minimize rear-end collisions and improve safety at the signalized intersections.

scholarly journals City-Wide Eco-Routing Navigation Considering Vehicular Communication Impacts

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 290 ◽  
Author(s):  
Ahmed Elbery ◽  
Hesham Rakha
Keyword(s):  
System Performance ◽  
Large Scale ◽  
Penetration Rate ◽  
Transportation Systems ◽  
Pollutant Emissions ◽  
Market Penetration ◽  
Vehicular Communication ◽  
Traffic Demand ◽  
Realistic Communication ◽  
The Impact

Intelligent Transportation Systems (ITSs) utilize Vehicular Ad-hoc Networks (VANETs) to collect, disseminate, and share data with the Traffic Management Center (TMC) and different actuators. Consequently, packet drop and delay in VANETs can significantly impact ITS performance. Feedback-based eco-routing (FB-ECO) is a promising ITS technology, which is expected to reduce vehicle fuel/energy consumption and pollutant emissions by routing drivers through the most environmentally friendly routes. To compute these routes, the FB-ECO utilizes VANET communication to update link costs in real-time, based on the experiences of other vehicles in the system. In this paper, we study the impact of vehicular communication on FB-ECO navigation performance in a large-scale real network with realistic calibrated traffic demand data. We conduct this study at different market penetration rates and different congestion levels. We start by conducting a sensitivity analysis of the market penetration rate on the FB-ECO system performance, and its network-wide impacts considering ideal communication. Subsequently, we study the impact of the communication network on system performance for different market penetration levels, considering the communication system. The results demonstrate that, for market penetration levels less than 30%, the eco-routing system performs adequately in both the ideal and realistic communication scenarios. It also shows that, for realistic communication, increasing the market penetration rate results in a network-wide degradation of the system performance.

The European Union and Global Governance

2017 ◽  
Author(s):  
Thomas Christiansen
Keyword(s):  
European Union ◽  
Global Governance ◽  
Final Section ◽  
The European Union ◽  
Test Bed ◽  
Way Of Life ◽  
New Ideas ◽  
The Impact ◽  
Global Powers

This chapter discusses whether the European Union has a distinctive take on, and may make a particular contribution to, global governance, as well as the reverse image of the impact that global governance has in the development of integration in Europe. This includes a focus on collective norms and interests as expressed through common institutions, policies, and activities. In doing so, the chapter compares and contrasts the evolution of a supranational order in Europe with the growth of global regimes and the emergence of a multipolar world, and explores the nature of the EU’s relationships with other global powers and regions. In a final section, the chapter asks whether the EU’s relationship with global developments is best seen as a test-bed for new ideas, procedures, and concepts; a construction for the defence of a privileged way of life; or an archaic remnant of a different era.

scholarly journals Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2690
Author(s):  
Bo Pan ◽  
Xuguang Wang ◽  
Zhenyang Xu ◽  
Lianjun Guo ◽  
Xuesong Wang
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Joint Angle ◽  
Simulation Software ◽  
Dissipated Energy ◽  
Energy Structure ◽  
Joint Angles ◽  
Crack Penetration ◽  
Before And After ◽  
The Impact

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.

A simplified iterative approach for testing the pulse derailment of light rail vehicles across a viaduct to near-fault earthquake scenarios

2021 ◽  
pp. 095440972098741
Author(s):  
Ling-Kun Chen ◽  
Peng Liu ◽  
Li-Ming Zhu ◽  
Jing-Bo Ding ◽  
Yu-Lin Feng ◽  
...  
Keyword(s):  
Ground Motions ◽  
Simulation Software ◽  
Light Rail ◽  
Rail Transit ◽  
Light Rail Transit ◽  
Seismic Responses ◽  
Near Fault ◽  
Rail Vehicle ◽  
Pulse Type ◽  
The Impact

Near-fault (NF) earthquakes cause severe bridge damage, particularly urban bridges subjected to light rail transit (LRT), which could affect the safety of the light rail transit vehicle (“light rail vehicle” or “LRV” for short). Now when a variety of studies on the fault fracture effect on the working protection of LRVs are available for the study of cars subjected to far-reaching soil motion (FFGMs), further examination is appropriate. For the first time, this paper introduced the LRV derailment mechanism caused by pulse-type near-fault ground motions (NFGMs), suggesting the concept of pulse derailment. The effects of near-fault ground motions (NFGMs) are included in an available numerical process developed for the LRV analysis of the VBI system. A simplified iterative algorithm is proposed to assess the stability and nonlinear seismic response of an LRV-reinforced concrete (RC) viaduct (LRVBRCV) system to a long-period NFGMs using the dynamic substructure method (DSM). Furthermore, a computer simulation software was developed to compute the nonlinear seismic responses of the VBI system to pulse-type NFGMs, non-pulse-type NFGMs, and FFGMs named Dynamic Interaction Analysis for Light-Rail-Vehicle Bridge System (DIALRVBS). The nonlinear bridge seismic reaction determines the impact of pulses on lateral peak earth acceleration (Ap) and lateral peak land (Vp) ratios. The analysis results quantify the effects of pulse-type NFGMs seismic responses on the LRV operations' safety. In contrast with the pulse-type non-pulse NFGMs and FFGMs, this article's research shows that pulse-type NFGM derail trains primarily via the transverse velocity pulse effect. Hence, this study's results and the proposed method can improve the LRT bridges' seismic designs.

scholarly journals An Efficiency Enhancing Methodology for Multiple Autonomous Vehicles in an Urban Network Adopting Deep Reinforcement Learning

2021 ◽  
Vol 11 (4) ◽  
pp. 1514 ◽  
Author(s):  
Quang-Duy Tran ◽  
Sang-Hoon Bae
Keyword(s):  
Reinforcement Learning ◽  
Traffic Congestion ◽  
Autonomous Vehicles ◽  
Penetration Rate ◽  
Autonomous Vehicle ◽  
Effective Means ◽  
Urban Network ◽  
Learning Agents ◽  
Policy Optimization ◽  
The Impact

To reduce the impact of congestion, it is necessary to improve our overall understanding of the influence of the autonomous vehicle. Recently, deep reinforcement learning has become an effective means of solving complex control tasks. Accordingly, we show an advanced deep reinforcement learning that investigates how the leading autonomous vehicles affect the urban network under a mixed-traffic environment. We also suggest a set of hyperparameters for achieving better performance. Firstly, we feed a set of hyperparameters into our deep reinforcement learning agents. Secondly, we investigate the leading autonomous vehicle experiment in the urban network with different autonomous vehicle penetration rates. Thirdly, the advantage of leading autonomous vehicles is evaluated using entire manual vehicle and leading manual vehicle experiments. Finally, the proximal policy optimization with a clipped objective is compared to the proximal policy optimization with an adaptive Kullback–Leibler penalty to verify the superiority of the proposed hyperparameter. We demonstrate that full automation traffic increased the average speed 1.27 times greater compared with the entire manual vehicle experiment. Our proposed method becomes significantly more effective at a higher autonomous vehicle penetration rate. Furthermore, the leading autonomous vehicles could help to mitigate traffic congestion.

The dynamics of regional and global expansion

2015 ◽  
Vol 23 (4) ◽  
pp. 306-327 ◽  
Author(s):  
Christian Geisler Asmussen ◽  
Bo Bernhard Nielsen ◽  
Tom Osegowitsch ◽  
Andre Sammartino
Keyword(s):  
Design Methodology ◽  
Global Market ◽  
Market Penetration ◽  
Content Type ◽  
Global Expansion ◽  
Rates Of Change ◽  
Global Space ◽  
The Impact ◽  
The Relationship ◽  
Over Time

Purpose – The purpose of this paper is to model and test the dynamics of home-regional and global penetration by multi-national enterprises (MNEs). Design/methodology/approach – Drawing on international business (IB) theory, the authors model MNEs adjusting their home-regional and global market presence over time. The authors test the resulting hypotheses using sales data from a sample of 220 of the world’s largest MNEs over the period 1995-2005. The authors focus specifically on the relationship between levels of market penetration inside and outside the home region and rates of change in each domain. Findings – The authors demonstrate that MNEs do penetrate both home-regional and global markets, often simultaneously, and that penetration levels often oscillate within an MNE over time. The authors show firms’ rates of regional and global expansion to be affected by their existing regional and global penetration, as well as their interplay. Finally, the authors identify differences in the steady states at which firms stabilize their penetration levels in the home-regional and the global space. The findings broadly confirm the MNE as an interdependent portfolio with important regional demarcations. Originality/value – The authors identify complex interdependencies between home-regional and global penetration and growth, paving the way for further studies of the impact of regions on MNE expansion.

Design and simulation analysis of impact-resistant flexible drill pipe for rock-breaking rig

2021 ◽  
pp. 095745652110307
Author(s):  
Kangping Gao ◽  
Xinxin Xu ◽  
Ning Shi ◽  
Shengjie Jiao
Keyword(s):  
Impact Force ◽  
Drill Pipe ◽  
Rock Breaking ◽  
Control Model ◽  
Simulation Software ◽  
System Stability ◽  
Series Elastic Actuator ◽  
Pipe Model ◽  
The Impact ◽  
Series Elastic

In the process of drilling and coring by the rock-breaking rig, the drill rod is affected by the intermittent impact force, which reduces the efficiency of the rig to break the rock and increases the cost of the drilling and coring. Therefore, it is very important to improve the impact resistance of the drill pipe during the rock-breaking process. To achieve this goal, a flexible design of the drill pipe was carried out, and a dynamical model of the drilling rig based on a series elastic actuator was established. Considering the dynamic performance of the system, a torque feedforward link is introduced and a control model based on the force source is established. The influence of the equivalent inertia of the transmission system and the series elastic actuator damping coefficient on the system stability was analyzed by drawing the frequency domain characteristic curve of the system. By using the control and Simulink simulation software, the electromechanical simulation of the model is carried out, and the torque step tracking response of the system is obtained. A torque feedforward link is introduced to establish the control model of the system based on force source. Through dynamic simulation software ADAMS, dynamic and static impact simulation experiments were carried out on the system. The results show that when a force of 200 N is applied to the output end of the drill pipe in the tangential direction, the maximum moments received by the joint under static and dynamic environments are 34.1 N·m and 57.9 N·m, respectively. When the impact force disappears, the time required for the flexible drill pipe to reach a stable state is only 0.15 s, which verifies that the series elastic actuator–based drill pipe model can alleviate the impact of the external environment and protect the internal structure of the rig.

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