scholarly journals Distributed Urban Platooning towards High Flexibility, Adaptability, and Stability

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2684
Author(s):  
Sangsoo Jeong ◽  
Youngmi Baek ◽  
Sang H. Son
Keyword(s):  
Travel Time ◽  
High Mobility ◽  
Propagation Delay ◽  
Urban Environments ◽  
Sequential Data ◽  
Service Channel ◽  
Broadcast Storm ◽  
Vehicle Platooning ◽  
Data Propagation ◽  
Vehicle Platoon

Vehicle platooning reduces the safety distance between vehicles and the travel time of vehicles so that it leads to an increase in road capacity and to saving fuel consumption. In Europe, many projects for vehicle platooning are being actively developed, but mostly focus on truck platooning on the highway with a simpler topology than that of the urban road. When an existing vehicle platoon is applied to urban roads, many challenges are more complicated to address than highways. They include complex topology, various routes, traffic signals, intersections, frequent lane change, and communication interference depending on a higher vehicle density. To address these challenges, we propose a distributed urban platooning protocol (DUPP) that enables high mobility and maximizes flexibility for driving vehicles to conduct urban platooning in a decentralized manner. DUPP has simple procedures to perform platooning maneuvers and does not require explicit conforming for the completion of platooning maneuvers. Since DUPP mainly operates on a service channel, it does not cause negative side effects on the exchange of basic safety messages on a control channel. Moreover, DUPP does not generate any data propagation delay due to contention-based channel access since it guarantees sequential data transmission opportunities for urban platooning vehicles. Finally, to address a problem of the broadcast storm while vehicles notify detected road events, DUPP performs forwarder selection using an analytic hierarchy process. The performance of the proposed DUPP is compared with that of ENSEMBLE which is the latest European platooning project in terms of the travel time of vehicles, the lifetime of an urban platoon, the success ratio of a designed maneuver, the external cost and the periodicity of the urban platooning-related transmissions, the adaptability of an urban platoon, and the forwarder selection ratio for each vehicle. The results of the performance evaluation demonstrate that the proposed DUPP is well suited to dynamic urban environments by maintaining a vehicle platoon as stable as possible after DUPP flexibly and quickly forms a vehicle platoon without the support of a centralized node.

scholarly journals A Parallel Meta-Heuristic Approach to Reduce Vehicle Travel Time in Smart Cities

2020 ◽  
Author(s):  
Hector Rico-Garcia ◽  
Jose-Luis Sanchez-Romero ◽  
Antonio Jimeno-Morenilla ◽  
Hector Migallon-Gomis
Keyword(s):  
Travel Time ◽  
Smart City ◽  
Smart Cities ◽  
Travelling Salesman Problem ◽  
Urban Environments ◽  
Departure Point ◽  
Classic Problem ◽  
Iot Devices ◽  
Vehicle Travel Time ◽  
Gpu Architecture

The development of the smart city concept and the inhabitants’ need to reduce travel time, as well as society’s awareness of the reduction of fuel consumption and respect for the environment, lead to a new approach to the classic problem of the Travelling Salesman Problem (TSP) applied to urban environments. This problem can be formulated as “Given a list of geographic points and the distances between each pair of points, what is the shortest possible route that visits each point and returns to the departure point?” Nowadays, with the development of IoT devices and the high sensoring capabilities, a large amount of data and measurements are available, allowing researchers to model accurately the routes to choose. In this work, the purpose is to give solution to the TSP in smart city environments using a modified version of the metaheuristic optimization algorithm TLBO (Teacher Learner Based Optimization). In addition, to improve performance, the solution is implemented using a parallel GPU architecture, specifically a CUDA implementation.

scholarly journals Evaluation of operational performance as a means for deciding about intermodal passenger transport improvements in urban environments

TRANSPORTES ◽  
2021 ◽  
Author(s):  
Luiz Guimarães Ribeiro Neto ◽  
Maria Leonor Alves Maia
Keyword(s):  
Factor Analysis ◽  
Performance Analysis ◽  
Travel Time ◽  
Urban Environments ◽  
Urban Transport ◽  
Metropolitan Region ◽  
Operational Performance ◽  
Transport Systems ◽  
Passenger Transport ◽  
Available Information

Regarding intermodal urban transport systems for passengers, there is no recognized standard for performance analysis. Detecting the weaknesses of such systems can allow managers to carry out more assertive, corrective actions and make them more attractive to users. The main objective of this article is to propose a model for evaluating the performance of intermodal travel for passengers in urban environments. The exploratory factor analysis was the method used to evaluate and classify the variables that constitute the proposed standard. The results show that the factors related to travel time, infrastructure and available information are the most important characteristics for the interviewed public. The operational performance analysis carried out in the Metropolitan Region of Recife, state of Pernambuco, Brazil, reveals the difficulties faced by the citizens while making an intermodal trip, which may be contributing to a reduction in the number of users of the passenger transport system.

scholarly journals The Model of the Optimal Number of Public Transport Vehicles in Mixed Traffic Flow Conditions: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Milja M. Simeunović ◽  
Vuk Z. Bogdanović ◽  
Milan M. Simeunović ◽  
Pavle M. Pitka ◽  
Zoran M. Papić ◽  
...  
Keyword(s):  
Travel Time ◽  
Traffic Flow ◽  
Public Transport ◽  
Transport Model ◽  
Optimal Number ◽  
Urban Environments ◽  
Mixed Traffic ◽  
Street Network ◽  
Mixed Traffic Flow ◽  
Flow Parameters

Bus passenger transport is very important for sustainable urban mobility, and due to the characteristics of the street network, it is usually realized in the conditions of mixed traffic flow. Disturbances and sudden changes of traffic flow parameters occurring in the street network in a mixed traffic flow affect the disruptions in schedule and travel time of all vehicles in the traffic flow, including public transport (PT) vehicles. In order to keep to the planned schedule in the peak hours of PT lines carried out in the conditions of mixed traffic flow, the operators introduce new vehicles or reduce the vehicles’ dwell time at terminuses, which is often impossible to do. The use of a larger number of public transport vehicles increases the fuel consumption, pollutants’ emission, and the operating costs. In this paper, a network optimization model was developed for defining the influence of the change of traffic flow parameters in a mixed traffic flow on travel time of PT vehicles. The model takes into consideration uncertain time unevenness of the change of traffic flow parameters, which enables determining the optimization of travel time and defining the necessary number of public transport vehicles for the purpose of keeping to the planned schedule. In order to develop the transport model, counting and analysis of the characteristics of traffic flow at 61 intersections on the city territory were carried out. The model was tested on bus line number 4 of PT in Novi Sad. The model showed that it is possible to achieve certain savings regarding the number of vehicles with the unchanged headway, that is, the unchanged level of service which is offered to the users. With the application of the model in real traffic conditions, significant savings, as well as operating and external costs’ reduction, can be achieved, which contributes to the sustainability of public bus transport in urban environments.

scholarly journals Exploring the Spatial-Temporal Characteristics of Traditional Public Bicycle Use in Yancheng, China: A Perspective of Time Series Cluster of Stations

2020 ◽  
Vol 12 (16) ◽  
pp. 6370
Author(s):  
Zhan Gao ◽  
Sheng Wei ◽  
Lei Wang ◽  
Sijia Fan
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Urban Environments ◽  
Series Data ◽  
Sequential Data ◽  
Time Warping ◽  
Large Cities ◽  
Points Of Interest ◽  
Transportation Development ◽  
Dynamic Time

Traditional dock-based public bicycle systems continue to dominate cycling in most cities, even though bicycle-sharing services are an increasingly popular means of transportation in many of China’s large cities. A few studies investigated the traditional public bicycle systems in small and mid-sized cities in China. The time series clustering method’s advantages for analyzing sequential data used in many transportation-related studies are restricted to time series data, thereby limiting applications to transportation planning. This study explores the characteristics of a typical third-tier city’s public bicycle system (where there is no bicycle-sharing service) using station classification via the time series cluster algorithm and bicycle use data. A dynamic time warping distance-based k-medoids method classifies public bicycle stations by using one-month bicycle use data. The method is further extended to non-time series data after format conversion. The paper identified three clusters of stations and analyzed the relationships between clusters’ features and the stations’ urban environments. Based on points-of-interest data, the classification results were validated using the enrichment factor and the proportional factor. The method developed in this paper can apply to other transportation analysis and the results also yielded relevant strategies for transportation development and planning.

scholarly journals Position-based emergency message dissemination for Internet of vehicles

2019 ◽  
Vol 15 (7) ◽  
pp. 155014771986158 ◽  
Author(s):  
Muhammad Ali ◽  
Asad W Malik ◽  
Anis U Rahman ◽  
Sohail Iqbal ◽  
Mian M Hamayun
Keyword(s):  
Vehicular Networks ◽  
Data Dissemination ◽  
High Mobility ◽  
Communication Technologies ◽  
Communication Delays ◽  
Internet Of Vehicles ◽  
Vehicle Communication ◽  
Broadcast Storm ◽  
Vehicle To Vehicle ◽  
Timely Dissemination

With the advancement in communication technologies, Internet of vehicles presents a new set of opportunities to efficiently manage transportation problems using vehicle-to-vehicle communication. However, high mobility in vehicular networks causes frequent changes in network topology, which leads to network instability. This frequently results in emergency messages failing to reach the target vehicles. To overcome this problem, we propose a data dissemination scheme for such messages in vehicular networks, based on clustering and position-based broadcast techniques. The vehicles are dynamically clustered to handle the broadcast storm problem, and a position-based technique is proposed to reduce communication delays, resulting in timely dissemination of emergency messages. The simulation results show that the transmission delay, information coverage, and packet delivery ratios improved up to 14%, 9.7%, and 5.5%, respectively. These results indicate that the proposed scheme is promising as it outperforms existing techniques.

EFFECTS OF PARAMETER VARIATIONS ON TIMING CHARACTERISTICS OF CLOCKED REGISTERS

2009 ◽  
Vol 18 (07) ◽  
pp. 1309-1320
Author(s):  
WILLIAM R. ROBERTS ◽  
DIMITRIOS VELENIS
Keyword(s):  
Supply Voltage ◽  
Setup Time ◽  
Oxide Thickness ◽  
Propagation Delay ◽  
Timing Constraints ◽  
Power Supply Voltage ◽  
Synchronous System ◽  
Data Propagation ◽  
Gate Oxide Thickness ◽  
Parameter Variations

Violations in the timing constraints of a clocked register can cause a synchronous system to malfunction. The effects of parameter variations on the timing characteristics of registers that determine the timing constraints are investigated in this paper. The sensitivity of the setup time and data propagation delay to variations in power supply voltage, temperature, and gate oxide thickness is demonstrated for four different register designs. Furthermore, design modifications are proposed that enhance the robustness of each register to variation effects.

scholarly journals Routing Algorithm To Eliminate Stale Routes (RAESR) In Mobile Ad Hoc Networks

2019 ◽  
Vol 8 (12) ◽  
pp. 4503-4509
Keyword(s):  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Routing Algorithm ◽  
High Mobility ◽  
Propagation Delay ◽  
Link Failure ◽  
Mobile Nodes ◽  
Routing Overhead ◽  
Mobile Ad Hoc ◽  
Hoc Networks

Mobile Ad-hoc Network (MANET) is a collection of self sustaining mobile nodes which are connected through many wi-fi links to form a temporary communication for sharing information between the users. Mobile nodes behave as a host as well as router. As nodes in MANET posse’s mobility in traits frequently leads to irregular link between the nodes. Link failure directs a significant routing overhead during high mobility and also maintaining all the information associated with nodes and routing paths are considered as an extra overhead on the table. In order to overcome these issues, the routing algorithm to eliminate stare routed in routing cache. The neighbor degree centrality table is introduced to recognize the valuable nodes, using the valuable nodes the routes are discovered and link failure information are disseminated across the network wide. The results and findings show that the elimination of stale routes leads to significant reduction in routing overhead which in turn reduces the route error propagation delay

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