55 research outputs found
A distance-based tool-set to track inconsistent urban structures through complex-networks
Complex networks can be used for modeling street meshes and urban
agglomerates. With such a model, many aspects of a city can be investigated to
promote a better quality of life to its citizens. Along these lines, this paper
proposes a set of distance-based pattern-discovery algorithmic instruments to
improve urban structures modeled as complex networks, detecting nodes that lack
access from/to points of interest in a given city. Furthermore, we introduce a
greedy algorithm that is able to recommend improvements to the structure of a
city by suggesting where points of interest are to be placed. We contribute to
a thorough process to deal with complex networks, including mathematical
modeling and algorithmic innovation. The set of our contributions introduces a
systematic manner to treat a recurrent problem of broad interest in cities.Comment: Paper to be published on the International Conference on
Computational Science (ICCS), 201
Complex Network Tools to Understand the Behavior of Criminality in Urban Areas
Complex networks are nowadays employed in several applications. Modeling
urban street networks is one of them, and in particular to analyze criminal
aspects of a city. Several research groups have focused on such application,
but until now, there is a lack of a well-defined methodology for employing
complex networks in a whole crime analysis process, i.e. from data preparation
to a deep analysis of criminal communities. Furthermore, the "toolset"
available for those works is not complete enough, also lacking techniques to
maintain up-to-date, complete crime datasets and proper assessment measures. In
this sense, we propose a threefold methodology for employing complex networks
in the detection of highly criminal areas within a city. Our methodology
comprises three tasks: (i) Mapping of Urban Crimes; (ii) Criminal Community
Identification; and (iii) Crime Analysis. Moreover, it provides a proper set of
assessment measures for analyzing intrinsic criminality of communities,
especially when considering different crime types. We show our methodology by
applying it to a real crime dataset from the city of San Francisco - CA, USA.
The results confirm its effectiveness to identify and analyze high criminality
areas within a city. Hence, our contributions provide a basis for further
developments on complex networks applied to crime analysis.Comment: 7 pages, 2 figures, 14th International Conference on Information
Technology : New Generation
Enhancing Global Maritime Traffic Network Forecasting with Gravity-Inspired Deep Learning Models
Aquatic non-indigenous species (NIS) pose significant threats to
biodiversity, disrupting ecosystems and inflicting substantial economic damages
across agriculture, forestry, and fisheries. Due to the fast growth of global
trade and transportation networks, NIS has been introduced and spread
unintentionally in new environments. This study develops a new physics-informed
model to forecast maritime shipping traffic between port regions worldwide. The
predicted information provided by these models, in turn, is used as input for
risk assessment of NIS spread through transportation networks to evaluate the
capability of our solution. Inspired by the gravity model for international
trades, our model considers various factors that influence the likelihood and
impact of vessel activities, such as shipping flux density, distance between
ports, trade flow, and centrality measures of transportation hubs. Accordingly,
this paper introduces transformers to gravity models to rebuild the short- and
long-term dependencies that make the risk analysis feasible. Thus, we introduce
a physics-inspired framework that achieves an 89% binary accuracy for existing
and non-existing trajectories and an 84.8% accuracy for the number of vessels
flowing between key port areas, representing more than 10% improvement over the
traditional deep-gravity model. Along these lines, this research contributes to
a better understanding of NIS risk assessment. It allows policymakers,
conservationists, and stakeholders to prioritize management actions by
identifying high-risk invasion pathways. Besides, our model is versatile and
can include new data sources, making it suitable for assessing international
vessel traffic flow in a changing global landscape
Maritime Tracking Data Analysis and Integration with AISdb
Efficiently handling Automatic Identification System (AIS) data is vital for
enhancing maritime safety and navigation, yet is hindered by the system's high
volume and error-prone datasets. This paper introduces the Automatic
Identification System Database (AISdb), a novel tool designed to address the
challenges of processing and analyzing AIS data. AISdb is a comprehensive,
open-source platform that enables the integration of AIS data with
environmental datasets, thus enriching analyses of vessel movements and their
environmental impacts. By facilitating AIS data collection, cleaning, and
spatio-temporal querying, AISdb significantly advances AIS data research.
Utilizing AIS data from various sources, AISdb demonstrates improved handling
and analysis of vessel information, contributing to enhancing maritime safety,
security, and environmental sustainability efforts
Topological street-network characterization through feature-vector and cluster analysis
Complex networks provide a means to describe cities through their street
mesh, expressing characteristics that refer to the structure and organization
of an urban zone. Although other studies have used complex networks to model
street meshes, we observed a lack of methods to characterize the relationship
between cities by using their topological features. Accordingly, this paper
aims to describe interactions between cities by using vectors of topological
features extracted from their street meshes represented as complex networks.
The methodology of this study is based on the use of digital maps. Over the
computational representation of such maps, we extract global complex-network
features that embody the characteristics of the cities. These vectors allow for
the use of multidimensional projection and clustering techniques, enabling a
similarity-based comparison of the street meshes. We experiment with 645 cities
from the Brazilian state of Sao Paulo. Our results show how the joint of global
features describes urban indicators that are deep-rooted in the network's
topology and how they reveal characteristics and similarities among sets of
cities that are separated from each other.Comment: Paper to be published on the International Conference on
Computational Science (ICCS), 201
Das Cidades às Séries: Redes Complexas e Aprendizado Profundo para Aprimorar Análises Espaciais e Temporais
The relationship between different entities is a property that can be represented as a graph, structured sets formed by entities (i.e., vertices) and relationships (i.e., edges). Graphs have often been used to answer questions about the interaction between entities from the real world by analyzing their vertices and edges (i.e., the graphs topology). On the other hand, complex networks are known to be graphs of non-trivial topology, capable of representing human phenomena such as cities urbanization, peoples movement, and migration, besides epidemic processes. However, graph theory and network science, the research fields that oversee the study of graphs and complex networks, have also been traversed in the realm of artificial intelligence, in which the analysis of the interaction between different entities is transposed to the internal learning process of algorithms. In this sense, this thesis introduces complex networks and supervised learning (classification and regression) techniques to improve understanding of human phenomena inherent to street networks, pendular migration, and pandemics progression through computational analysis and modeling. Accordingly, we contribute with: (i) techniques for identifying inconsistencies in the urban plan while tracking the most influential vertices; (ii) a methodology for analyzing and predicting links in the scope of human mobility between cities through machine learning algorithms; and (iii) a new neural network architecture capable of modeling dynamic processes observed in spatial and temporal data with applications on different domains. These results reiterate the potential of graphs and complex networks in solving problems related to analyzing human phenomena and modeling their evolutive processes across space and time when used together with articial intelligence learning algorithms.A relação entre diferentes entidades de um conjunto de dados é uma propriedade passível de ser representada por um grafo, os quais são conjuntos estruturados formados por entidades (i.e., vértices) e relacionamentos (i.e., arestas). Por muitas vezes grafos foram utilizados para responder questionamentos sobre a interação entre entidades do mundo real pela análise de seus vértices e arestas (i.e., topologia do grafo). As redes complexas, por outro lado, ficaram conhecidas por serem grafos de topologia não trivial. Entre suas aplicações, destaca-se a representação de fenômenos humanos como a urbanização de cidades, o movimento migratório de populações, e a propagação de pandemias. A teoria dos grafos e a ciência de redes, os campos de pesquisa que regem o estudo de grafos e redes complexas, tem sido explorados com sinergia no âmbito da inteligencia artificial, no qual transpõe-se a análise da interação entre diferentes entidades para o processo interno de aprendizado computacional dos algoritmos. Neste sentido, a presente tese introduz um ferramental de redes complexas juntamente com técnicas de aprendizado supervisionado de classificação e regressão de modo a contribuir com o entendimento de fenômenos humanos inerentes às malhas viárias, migrações pendulares, e progressões pandêmicas por meio de modelagem e análise computacional. Entre os resultados alcançados, estão: (i) técnicas de identificação de falhas de planejamento urbano ao mesmo tempo em que se auxilia na análise da topologia da rede complexa para diferenciar os vértices mais influentes; (ii) uma metodologia de análise e predição de links em redes complexas no âmbito de mobilidade humana entre cidades por meio de aprendizado de máquina; e, (iii) uma nova arquitetura de rede neural capaz de modelar processos dinâmicos observados em dados variantes no espaço e no tempo, com aplicações de alcance a diferentes domínios. Tais resultados reiteram o potencial dos grafos e das redes complexas na solução de problemas conectados à análise de diferentes fenômenos humanos, bem como a previsão de seus processos evolutivos no espaço e no tempo, quando utilizados conjuntamente com os algoritmos de aprendizado computacional provenientes da inteligência artificial
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