Incorporating the GEMV2 geometry-based vehicle-to-vehicle radio propagation channe model into de artery simulation framework for vanet applications

Orientador: Prof. Dr. Evelio Martin Garcia FernándezCoorientador: Prof. Dr. Christian FacchiDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Engenharia Elétrica e e em Engenharia Automotiva Internacional, Faculdade de Engenharia Elétrica e Ciências da Computação, Technische Hochschule Ingolstadt. Defesa : Curitiba, 27/08/2018Inclui referências: p.70-73Resumo: A comunicação veicular tem como principal objetivo a otimização do tráfego e a diminuição de acidentes nas estradas. Como trata-se de um item de segurança, é necessário que o sistema seja massivamente testado em diversas situações possíveis antes de ser colocado em prática, o que tornaria a aplicação inviável devido ao elevado custo e ao tempo. Através de simuladores computacionais é possível realizar essa operação mais eficientemente assim como confibializar o sistema como um todo. Para isso é necessário que o simulador veicular possua uma precisão mais próxima da realidade possível com uma alta escabilidade, entretanto, com um processo computacional executável. Nesse contexto, essa dissertação tem o objetivo de tornar o ambiente virtual mais realístico através da implantação de um modelo de rádio propagação propício para o ambiente veicular, o qual diferencia dos modelos tradicionais devido à alta mobilidade dos comunicantes (carros) em alta velocidade e o impacto dos mesmos na comunicação. Como simulador, foi utilizado o framework de simulação Artery, o qual é uma extensão melhorada do VEINS uma vez que agrega as funcionalidades de comunicação europeia VANET no mesmo e aumenta sua escabilidade. Além disso o Artery faz uso do Vanetza, o qual é responsável pela implementação da pilha de protocolo do ETSI ITS-G5. Tanto o Artery e Vanetza são desenvolvidos sob a plataforma Omnet++ e possuem licença de código aberto. O GEMV² é um modelo de rádio propagação determinístico e estocástico, o qual considera o impacto dos demais veículos sobre o canal de comunicação veicular. Além disso, apresenta um modelo eficiente para realísticas simulações em larga escala com milhares de veículos comunicantes em vários ambientes veiculares (urbano, rural, rodovia). Além disso apresenta um ótimo tradeoff entre escabilidade e precisão, tendo seu modelo validado através de medições de campo. Após a implementação do modelo GEMV² na estrutura de simulação Artery constatou-se uma alta sensibilidade do mesmo para variações no posicionamento da antena e do carro por si só, e assim como previsto, uma melhora aproximadamente de 82,3 dB na potência recebida se comparado com modelos tradicionais de rádio propagação usados até então no Artery, justificados pelas considerações geométricas que o modelo aplica. Palavras-chave: VANET, Artery, GEMV², modelo de rádio propagação veicular, framework de simulação. Omnet. MATLAB.Abstract: The main goal of vehicular communication is the traffic optimization and the reduction of accidents on the roads. Since it is a safety item, it is recommended that the system is massively tested in several possible situations before being put into practice, which would become the application infeasible due to the high cost and time. Through computer simulations, it is possible to perform these operations more efficiently as well as getting the whole system more trustworthy. That said, it is necessary that the network and traffic based vehicular simulator has an accuracy as close to reality as possible and with a high scalability, however, with an executable computational process. As for the simulator, the Artery simulation framework was used, which is based on VEINS and enhances this by adding the European VANET communication functionality and by increasing its scalability. In addition, Artery makes use of Vanetza, which is an implementation of the ETSI ITS-G5 protocol stack. Both Artery and Vanetza were developed under the Omnet ++ platform as open source. In this context, this dissertation aims to become the virtual environment more realistic by implementing a radio propagation model that fits the vehicular environment, which differentiates from the traditional models due to the high mobility of the communicators (vehicles) at high speed and their impact over the communication channel. The GEMV² is a deterministic and stochastic radio propagation model, which considers the impact of the other vehicles over the vehicular communication channel. In addition, it presents an efficient model for realistic large-scale simulations with thousands of communicating vehicles in various vehicular environments (urban, rural, highway). Furthermore, it can achieve a good scalability/accuracy tradeoff, having its model validated through extensive field measurements. After the implementation of the GEMV² model into the Artery simulation framework was noticed that the model has a high sensitive in relation to the antenna position and the vehicle's positioning itself. Moreover, as expected, an improvement of approximately 82.3 dB at received power emerged if compared to the traditional radio propagation models used by Artery till then, justified by the geometric considerations that the model applies. Keywords: VANET, Artery, GEMV², vehicular radio propagation model, simulation framework. Omnet. MATLAB

Model-based reuse for crosscutting frameworks: assessing reuse and maintenance effort

Abstract\ud \ud \ud \ud Background\ud Over the last years, a number of researchers have investigated how to improve the reuse of crosscutting concerns. New possibilities have emerged with the advent of aspect-oriented programming, and many frameworks were designed considering the abstractions provided by this new paradigm. We call this type of framework Crosscutting Frameworks (CF), as it usually encapsulates a generic and abstract design of one crosscutting concern. However, most of the proposed CFs employ white-box strategies in their reuse process, requiring two mainly technical skills: (i) knowing syntax details of the programming language employed to build the framework and (ii) being aware of the architectural details of the CF and its internal nomenclature. Also, another problem is that the reuse process can only be initiated as soon as the development process reaches the implementation phase, preventing it from starting earlier.\ud \ud \ud \ud Method\ud In order to solve these problems, we present in this paper a model-based approach for reusing CFs which shields application engineers from technical details, letting him/her concentrate on what the framework really needs from the application under development. To support our approach, two models are proposed: the Reuse Requirements Model (RRM) and the Reuse Model (RM). The former must be used to describe the framework structure and the later is in charge of supporting the reuse process. As soon as the application engineer has filled in the RM, the reuse code can be automatically generated.\ud \ud \ud \ud Results\ud We also present here the result of two comparative experiments using two versions of a Persistence CF: the original one, whose reuse process is based on writing code, and the new one, which is model-based. The first experiment evaluated the productivity during the reuse process, and the second one evaluated the effort of maintaining applications developed with both CF versions. The results show the improvement of 97% in the productivity; however little difference was perceived regarding the effort for maintaining the required application.\ud \ud \ud \ud Conclusion\ud By using the approach herein presented, it was possible to conclude the following: (i) it is possible to automate the instantiation of CFs, and (ii) the productivity of developers are improved as long as they use a model-based instantiation approach.The authors would like to thank CNPq for funding (Processes 132996/2010-3 and 560241/2010-0) and for the Universal Project (Process Number 483106/2009-7) in which this article was created. Thiago Gottardi would also like to thank FAPESP (Process 2011/04064-8)

Factors Associated with Emotion Regulation in Men with Internet Access Living in Brazil during the COVID-19 Pandemic

Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Objective: to evaluate the factors associated with emotion regulation in men with internet access living in Brazil during the COVID-19 pandemic. Method: an epidemiological survey, conducted with 1015 men. An electronic form was applied containing sociodemographic and occu-pational characteristics, support and coping strategies, as well as emotional and behavioral aspects. Emotion regulation was assessed using the Emotion Regulation Questionnaire. Results: The prevalence values observed were 44.6% for Low Cognitive Reappraisal and of 47.1% for High Emotional Sup-pression. The following factors were identified as associated: (a) with Low Cognitive Reappraisal: being aged 30 years old or more, practicing physical activity, worrying about social distancing and having positive emotions and feelings; and (b) with High Emotional Suppression: being heterosexual, non-white race/skin color, having security support or public administration, not sanitizing food, worrying about lack of physical activity and not having negative emotions. Conclusion: the adoption of emotion regulation strategies was associated with individual, contextual and emotional/behavioral characteristics. Masculinity ideals seem to exert an influence on these relationships.publishersversionpublishe

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest

South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on-line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub-regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events. © 2017 by the Ecological Society of Americ

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe