171 research outputs found
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
LIPIcs, Volume 274, ESA 2023, Complete Volume
LIPIcs, Volume 274, ESA 2023, Complete Volum
A Survey on the Communication Protocols and Security in Cognitive Radio Networks
A cognitive radio (CR) is a radio that can change its transmission parameters based on the perceived availability of the spectrum bands in its operating environment. CRs support dynamic spectrum access and can facilitate a secondary unlicensed user to efficiently utilize the available underutilized spectrum allocated to the primary licensed users. A cognitive radio network (CRN) is composed of both the secondary users with CR-enabled radios and the primary users whose radios need not be CR-enabled. Most of the active research conducted in the area of CRNs has been so far focused on spectrum sensing, allocation and sharing. There is no comprehensive review paper available on the strategies for medium access control (MAC), routing and transport layer protocols, and the appropriate representative solutions for CRNs. In this paper, we provide an exhaustive analysis of the various techniques/mechanisms that have been proposed in the literature for communication protocols (at the MAC, routing and transport layers), in the context of a CRN, as well as discuss in detail several security attacks that could be launched on CRNs and the countermeasure solutions that have been proposed to avoid or mitigate them. This paper would serve as a good comprehensive review and analysis of the strategies for MAC, routing and transport protocols and security issues for CRNs as well as would lay a strong foundation for someone to further delve onto any particular aspect in greater depth
Relações entre iniciação científica e aspectos socioeducacionais, acadêmicos e profissionais de egressos da Universidade Federal do Paraná
Orientador: Prof. Dr. Cícero Aparecido BezerraCoorientadora: Prof.ª Dr.ª Rafaela Mantovani FontanaTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Programa de Pós-Graduação em Gestão da Informação. Defesa : Curitiba, 04/05/2022Inclui referênciasResumo: A Iniciação Científica (IC) propicia o contato prematuro de discentes com o ambiente científico das universidades e possui papel estratégico na formação de alunos e na renovação de recursos humanos qualificados, seja para a pesquisa ou mesmo para o mercado de trabalho. Esta tese tem como objetivo analisar alunos egressos da Universidade Federal do Paraná (UFPR) entre os anos de 2005 a 2020, considerando caracerísticas dos escopos socioeducacional, acadêmico, científico e profissional, estabelecendo comparações e verificando diferenças conforme a participação na atividade de IC. Parte-se do pressuposto que a IC não exerce diferença na vida profissional do estudante, limitando os ganhos da atividade para a área científica, com ingresso na pós-graduação e publicação de artigos. Metodologicamente, o estudo possui natureza quantitativa, com dados coletados de múltiplas fontes. Informações socioeducacionais, acadêmicas e de participações em IC foram obtidas das próprias bases da UFPR - Sistema Integrado de Ensino (SEI), Núcleo de Concursos (NC) e Sistema de Iniciação Científica e Tecnológica (SICT). Para informações científicas de ingresso em pós-graduação e publicações, foram colhidos dados da plataforma Currículo Lattes, enquanto os dados profissionais foram selecionados da Relação Anual de Informações Sociais (RAIS). Para atingir o objetivo do estudo, técnicas estatísticas bivariadas e análise de correspondência múltipla foram empregadas em 37.516 egressos da UFPR - 8.133 com IC, 29.383 sem IC - de modo a identificar as características e diferenças entre os grupos IC x Sem IC, e validar protocolo de pesquisa e tese apresentadas. Os resultados apontaram que: i) no escopo socioeducacional, egressos que participaram da IC foram ligeiramente mais jovens; predominantemente do sexo feminino; demonstraram menor interesse em participar de atividades profissionais em tempo integral durante o curso; e apresentaram melhor desempenho no vestibular; não houve qualquer diferença para variáveis de cota ou raça; ii) no âmbito acadêmico, egressos com IC possuíram carga horária do curso maior; estiveram associados a cursos do turno matutino; e figuraram de maneira mais intensa nas áreas de Ciências Sociais Aplicadas e Ciências da Saúde; e também apresentaram maior índice de rendimento acadêmico; ii) no escopo científico, os egressos com IC apresentaram maior encaminhamento para cursos de pós-graduação stricto sensu e lato sensu, e médias maiores para todas as variáveis de publicações analisadas, tanto durante a graduação como após este período; iv) nas variáveis profissionais, houve maior empregabilidade ao longo dos anos para egressos sem IC; ao observar a empregabilidade para a área de docência, os percentuais foram maiores para os alunos IC; em todas as variáveis envolvendo a remuneração, não houve padrão que pudesse postar um grupo de maneira favorável ou mesmo de destaque em relação ao outro. Os resultados fortalecem a ideia de que os benefícios propiciados pela IC se encontram principalmente para a área científica dos estudantes egressos, com destaque no encaminhamento para a pós-graduação e publicações.Abstract: Undergraduate Research (UR) provides early contact of the students with the scientific environment of the universities and plays a strategic role in the training of students and the renewal of qualified human resources, whether for research or even for the labor market. This thesis aims to analyze students from the Federal University of Parana (UFPR) between the years 2005 to 2020, considering characteristics of the socio-educational, academic, scientific and professional scopes, establishing comparisons and verifying differences according to the participation in the UR activity. It is assumed that UR makes no difference in the student's academic and professional life, limiting the gains from the activity for the scientific area, with admission to graduate studies and publication of articles. Methodologically, the study has a quantitative nature, where data were collected from multiple sources. Socio-educational, academic and participation information in UR were collected from the UFPR's own bases - Integrated Teaching System (SEI), Contests Center (NC) and Scientific and Technological Initiation System (SICT). For graduate scientific information and publications, data were collected from the Curriculum Lattes platform, while professional data were selected from the Annual Social Information List (RAIS). To achieve the objective of the study, bivariate statistical techniques and multiple correspondence analysis were used in the 37,516 undergraduates of UFPR - 8.133 with UR, 29.383 without UR - in order to identify the characteristics and differences between the UR students gruoup vs No UR students grouo, and validate the research protocol and thesis presented. The results showed that: i) in the socio-educational scope, graduates who participated in the IC were slightly younger; predominantly female; showed less interest in participating in full-time professional activities during the course; and showed better performance in the entrance exam; there was no difference for quota or race variables; ii) in the academic sphere, graduates with UR had a higher course load; were associated with morning shift courses; and figured more intensely in the areas of Applied Social Sciences and Health Sciences; and also had a higher academic performance index; iii) in the scientific scope, UR graduates showed greates fowarding to stricto sensu and lato sensu graduate courses, and higher averages for all variables of analyzed publications, both during graduation and after this period; iv) in the professional variables, there was greater employability over the years for graduates without UR; when observing the employability for teaching in higher education, the percentages were higher for UR students; in all variables involving remuneration, there was no pattern that could place a group in a favorable way or even prominently in relation to the other. The results strengthen the idea that the benefits provided by the UR are mainly for the scientific area of the graduating st dents, with emphasis on the referral to postgraduate studies and publications
Optimal Spanners for Unit Ball Graphs in Doubling Metrics
Resolving an open question from 2006, we prove the existence of light-weight
bounded-degree spanners for unit ball graphs in the metrics of bounded doubling
dimension, and we design a simple -round distributed
algorithm in the LOCAL model of computation, that given a unit ball graph
with vertices and a positive constant finds a
-spanner with constant bounds on its maximum degree and its
lightness using only 2-hop neighborhood information. This immediately improves
the best prior lightness bound, the algorithm of Damian, Pandit, and Pemmaraju,
which runs in rounds in the LOCAL model, but has a
bound on its lightness, where is the ratio
of the length of the longest edge to the length of the shortest edge in the
unit ball graph. Next, we adjust our algorithm to work in the CONGEST model,
without changing its round complexity, hence proposing the first spanner
construction for unit ball graphs in the CONGEST model of computation. We
further study the problem in the two dimensional Euclidean plane and we provide
a construction with similar properties that has a constant average number of
edge intersections per node. Lastly, we provide experimental results that
confirm our theoretical bounds, and show an efficient performance from our
distributed algorithm compared to the best known centralized construction
Proceedings of the 9th Arab Society for Computer Aided Architectural Design (ASCAAD) international conference 2021 (ASCAAD 2021): architecture in the age of disruptive technologies: transformation and challenges.
The ASCAAD 2021 conference theme is Architecture in the age of disruptive technologies: transformation and challenges. The theme addresses the gradual shift in computational design from prototypical morphogenetic-centered associations in the architectural discourse. This imminent shift of focus is increasingly stirring a debate in the architectural community and is provoking a much needed critical questioning of the role of computation in architecture as a sole embodiment and enactment of technical dimensions, into one that rather deliberately pursues and embraces the humanities as an ultimate aspiration
Mobile Ad Hoc Networks
Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms
Recent Trends in Communication Networks
In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges
Wireless Sensor Networks
The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks
Mobile Ad-Hoc Networks
Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks
- …