Browsing by Author "Kokkinogenis, Zafeiris"
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- Assessing Communication Strategies in C-ITS using n-Person Prisoner 19s Dilemma PerspectivePublication . Costa, António; Kokkinogenis, Zafeiris; D'Orey, Pedro; Rossetti, Rosaldo J. F.In Cooperative Intelligent Transport Systems, road users and traffic managers share information for coordinating their actions to improve traffic efficiency allowing the driver to adapt to the traffic situation. Its effectiveness, however, depends on the user’s decision-making process, which is the main source of uncertainty in any mobility system and depends on the ability of the infrastructure to communicate timely and reliably. To cope with such a complex scenario, this paper proposes a game theory perspective based on the n-Person Prisoner’s Dilemma as a metaphor to represent the uncertainty of cooperation underlined by communication infrastructures in traveller information systems. Results highlighted a close relationship between the emergence of cooperation and network performance, as well as the impact of the communication failure on the loss of cooperation sustainment, which was not recovered after the system was re-established.
- Cooperative, Connected and Autonomous Mobility: Coordination at Intersections using Reservation-based MechanismsPublication . Filipe, Francisco; Kokkinogenis, Zafeiris; D'Orey, Pedro; Rossetti, Rosaldo J. F.Road transportation is fundamental for the movement of individuals and goods, also contributing to economic development. A significant contributor to urban road congestion is poor intersection control using conventional traffic signals. In this work, we present a decentralized multi-agent system mechanism for road intersection management for connected autonomous vehicles, including the coordination of platoon formations. We propose a reservation-based mechanism able to maximize the overall vehicle throughput at intersections. The study introduces i) auctions as an alternative to the First-Come-First-Serve policy for assigning reservations to vehicles and ii) a method for resolving disputes between conflicting reservations. The results demonstrate the benefits of using platooning for improving throughput and the average delay in intersection control. The distributed nature of the approach increases scalability by shifting the majority of the computing burden from the intersection manager to the driving agents.
- The trade-offs between Fog Processing and Communications in latency-sensitive Vehicular Fog ComputingPublication . Júnior, Francisco Mendonça; Kokkinogenis, Zafeiris; Dias, Kelvin; D'Orey, Pedro; Rossetti, Rosaldo J. F.In a vehicular fog computing paradigm, connected autonomous vehicles are envisioned as processing nodes (i.e. fog nodes) so that end-devices may offload processing tasks to them. As such, both local and distributed processing on fog nodes will depend heavily on wireless network conditions and the current traffic demand. In this work, we investigate the trade-offs on the operation of fog nodes under different vehicle densities and network conditions and formalize a Time Constrained One-Shot Open First Price Auction for resource allocation in vehicular fog computing. Through a large-scale simulation study, we assess important aspects of the performance of fog nodes in Vehicular Fog Computing. We show that current wireless network standards may dictate the limits of processing despite the availability of processing power of fog nodes. Our results indicate the existence of tradeoffs on the operation of fog nodes regarding message overhead and processing redundancy to achieve high task completion ratio. Finally, we evaluate the social welfare distribution of the task allocation achieved using the auction where higher message rates lead to higher costs.
- Transportation Policy Evaluation Using Minority Games and Agent-Based SimulationPublication . Baghcheband, Hajar; Kokkinogenis, Zafeiris; J. F. Rossetti, RosaldoTraffic congestion is an issue regarding the vitality of cities and the welfare of citizens. Transportation systems are using various technologies to allow users to adapt and make different decisions towards transportation modes. Modification and improvement of these systems affect the commuters' perspective and social welfare. In this study, the effect of road flow equilibrium on commuters' utilities with different types of transportation modes will be discussed. A simple network with two modes of transportation will be illustrated and three different cost policies were considered to test the efficiency of reinforcement learning in commuters' daily trip decision-making regarding time and mode. The artificial society of agents is simulated to analyse the results.