65 research outputs found
Transportation in Social Media: an automatic classifier for travel-related tweets
In the last years researchers in the field of intelligent transportation
systems have made several efforts to extract valuable information from social
media streams. However, collecting domain-specific data from any social media
is a challenging task demanding appropriate and robust classification methods.
In this work we focus on exploring geo-located tweets in order to create a
travel-related tweet classifier using a combination of bag-of-words and word
embeddings. The resulting classification makes possible the identification of
interesting spatio-temporal relations in S\~ao Paulo and Rio de Janeiro
A State-of-the-art Integrated Transportation Simulation Platform
Nowadays, universities and companies have a huge need for simulation and
modelling methodologies. In the particular case of traffic and transportation,
making physical modifications to the real traffic networks could be highly
expensive, dependent on political decisions and could be highly disruptive to
the environment. However, while studying a specific domain or problem,
analysing a problem through simulation may not be trivial and may need several
simulation tools, hence raising interoperability issues. To overcome these
problems, we propose an agent-directed transportation simulation platform,
through the cloud, by means of services. We intend to use the IEEE standard HLA
(High Level Architecture) for simulators interoperability and agents for
controlling and coordination. Our motivations are to allow multiresolution
analysis of complex domains, to allow experts to collaborate on the analysis of
a common problem and to allow co-simulation and synergy of different
application domains. This paper will start by presenting some preliminary
background concepts to help better understand the scope of this work. After
that, the results of a literature review is shown. Finally, the general
architecture of a transportation simulation platform is proposed
Densifying the sparse cloud SimSaaS: The need of a synergy among agent-directed simulation, SimSaaS and HLA
Modelling & Simulation (M&S) is broadly used in real scenarios where making
physical modifications could be highly expensive. With the so-called Simulation
Software-as-a-Service (SimSaaS), researchers could take advantage of the huge
amount of resource that cloud computing provides. Even so, studying and
analysing a problem through simulation may need several simulation tools, hence
raising interoperability issues. Having this in mind, IEEE developed a standard
for interoperability among simulators named High Level Architecture (HLA).
Moreover, the multi-agent system approach has become recognised as a convenient
approach for modelling and simulating complex systems. Despite all the recent
works and acceptance of these technologies, there is still a great lack of work
regarding synergies among them. This paper shows by means of a literature
review this lack of work or, in other words, the sparse Cloud SimSaaS. The
literature review and the resulting taxonomy are the main contributions of this
paper, as they provide a research agenda illustrating future research
opportunities and trends
Characterizing Geo-located Tweets in Brazilian Megacities
This work presents a framework for collecting, processing and mining
geo-located tweets in order to extract meaningful and actionable knowledge in
the context of smart cities. We collected and characterized more than 9M tweets
from the two biggest cities in Brazil, Rio de Janeiro and S\~ao Paulo. We
performed topic modeling using the Latent Dirichlet Allocation model to produce
an unsupervised distribution of semantic topics over the stream of geo-located
tweets as well as a distribution of words over those topics. We manually
labeled and aggregated similar topics obtaining a total of 29 different topics
across both cities. Results showed similarities in the majority of topics for
both cities, reflecting similar interests and concerns among the population of
Rio de Janeiro and S\~ao Paulo. Nevertheless, some specific topics are more
predominant in one of the cities
A software environment to integrate urban traffic simulation tasks
This paper deseribes the CA TIA software environment, whieh is oriented to tool integration. The main funetionality provided by CA TIA is the ability to support the traffie engineer throughout several phases and tools that are demanded to analyze urban traffie systerns. An open architecture eombined with an objeet-oriented data model of the applieation domain provides for advantageous features when eompared to elassieal tools and engineering environment for CATE (Computer Aided Traffie Engineering). The modeling, implementation and obtained results are deseribed, emphasizing the arehiteeture of the inter-tool eommunieation faeilities
240101
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.info:eu-repo/semantics/publishedVersio
220601
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.This work is a result of project DynamiCITY: Fostering Dynamic Adaptation of
Smart Cities to Cope with Crises and Disruptions [reference NORTE-01-0145-
FEDER-000073] supported by Norte Portugal Regional Operational Programme
(NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through
the European Regional Development Fund (ERDF). This work was also supported by national funds of FCT/MCTES (Portuguese Foundation for Science
and Technology), within the CISTER Research Unit (UIDP/UIDB/04234/2020).info:eu-repo/semantics/publishedVersio
- …