Modelação interpretativa da segurança e emissões em corredores de rotundas e semáforos

Scientific research has demonstrated that the operational, environmental and safety performance for pedestrians depend on the geometric and traffic stream characteristics of the roundabout. However, the implementation of roundabouts may result in a trade-off among capacity, environmental, and safety variables. Also, little is known about the potential impacts for traffic from the use of functionally interdependent roundabouts in series along corridors. Thus, this doctoral thesis stresses the importance of understanding in how roundabout corridors affect traffic performance, vehicular emissions and safety for vulnerable users as pedestrians. The development of a methodology capable of integrating corridor’s geometric and operational elements is a contribution of this work. The main objectives of the thesis are as follows: 1) to analyze the effect of corridor’s design features in the acceleration patterns and emissions; 2) to understand the differences in the spatial distribution of emissions between roundabouts in isolation and along corridors; 3) to compare corridors with different forms of intersections such as conventional roundabouts, turbo-roundabouts, traffic lights and stop-controlled intersections; and 4) to design corridor-specific characteristics to optimize vehicle delay, and global (carbon dioxide – CO2) and local (carbon monoxide – CO, nitrogen oxides – NOX and hydrocarbons – HC) pollutant emissions. Vehicle dynamics along with traffic and pedestrian flow data were collected from 12 corridors with conventional roundabouts located in Portugal, Spain and in the United States, 3 turbo-roundabout corridors in the Netherlands, and 1 mixed roundabout/traffic-lights/stop-controlled corridor in Portugal. Data for approximately 2,000 km of road coverage over the course of 50 h have been collected. Subsequently, a microscopic platform of traffic (VISSIM), emissions (Vehicle Specific Power – VSP) and safety (Surrogate Safety Assessment Model – SSAM) was introduced to faithful reproduce site-specific operations and to examine different alternative scenarios. The main research findings showed that the spacing between intersections influenced vehicles acceleration-deceleration patterns and emissions. In contrast, the deflection angle at the entrances (element that impacts emissions on isolated roundabouts) impacted slightly on the spatial distribution of emissions. It was also found that the optimal crosswalk locations along mid-block sections in roundabout corridor was generally controlled by spacing, especially in the case of short spacing between intersections (< 200 m). The implementation of turbo-roundabout in series along corridors increased emissions compared to conventional two-lane roundabout corridors (1-5%, depending on the pollutant). By changing the location of a roundabout or turbo-roundabout to increase spacing in relation to upstream/downstream intersection resulted in an improvement of corridor emissions. Under conditions of high through traffic and unbalanced traffic flows between main roads and minor roads, vehicles along roundabout corridors produced fewer emissions (~5%) than did vehicles along signalized corridors, but they emitted more gases (~12%) compared to a corridor with stop-controlled intersections. This research contributed to the current state-of-art by proving a full comprehension about the operational and geometric benefits and limitations of roundabout corridors. It also established correlations between geometric variable of corridors (spacing), crosswalk locations or traffic streams, and delay, and CO2, CO, NOX or HC variables. With this research, it has been demonstrated that the implementation of a given intersection form within a corridor focused on minimizing CO2 may not be translated to other variables such as CO or NOX. Therefore, the develop methodology is a decision supporting tool capable of assessing and selecting suitable traffic controls according the site-specific needs.Estudos anteriores demonstram que os desempenhos operacional, ambiental e ao nível da segurança para os peões de uma rotunda dependem das suas características geométricas e dos fluxos de tráfego e de peões. Porém, a implementação de uma rotunda pode traduzir-se numa avaliação de compromisso entre as variáveis da capacidade, emissões de poluentes e segurança. Para além disso, a informação relativa às potencialidades de rotundas interdependentes ao longo de corredores é diminuta. Assim, esta tese de doutoramento centra-se na compreensão dos impactos no desempenho do tráfego, emissões e segurança dos peões inerentes ao funcionamento de corredores de rotundas. Uma das contribuições deste trabalho é o desenvolvimento de uma metodologia capaz de avaliar as características geométricas e operacionais dos corredores de forma integrada. Os principais objetivos desta tese são: 1) analisar o impacto dos elementos geométricos dos corredores de rotundas em termos dos perfis de aceleração e das emissões; 2) investigar as principais diferenças na distribuição espacial das emissões entre rotundas isoladas e em corredores; 3) comparar os desempenhos operacional e ambiental de corredores com diferentes tipos de interseções tais como rotundas convencionais, turbo-rotundas, cruzamentos semaforizados e interseções prioritárias; e 4) dimensionar um corredor de modo a otimizar o atraso dos veículos, e emissões de poluentes globais (dióxido de carbono – CO2) e locais (monóxido de carbono – CO, óxidos de azoto – NOx e hidrocarbonetos – HC). O trabalho de monitorização experimental consistiu na recolha de dados da dinâmica do veículo, e volumes de tráfego e pedonais. Para tal, foram selecionados 12 corredores com rotundas convencionais em Portugal, Espanha e Estados Unidos da América, 3 corredores com turbo-rotundas na Holanda e ainda um corredor misto com rotundas, sinais luminosos e interseções prioritárias em Portugal. No total foram recolhidos aproximadamente 2000 km de dados da dinâmica do veículo, num total de 50 h. Foi utilizada uma plataforma de modelação microscópica de tráfego (VISSIM), emissões (Vehicle Specific Power – VSP) e segurança (Surrogate Safety Assessment Model – SSAM) de modo a replicar as condições de tráfego locais e avaliar cenários alternativos. Os resultados mostraram que o espaçamento entre interseções teve um impacto significativo nos perfis de aceleração e emissões. No entanto, tal não se verificou para o ângulo de deflexão de entrada (elemento fulcral nos níveis de emissões em rotundas isoladas), nomeadamente nos casos em que as rotundas adjacentes estavam próximas (< 200 m). A implementação de corredores de turbo-rotundas conduziu ao aumento das emissões face a um corredor convencional de rotundas com duas vias (1-5%, dependendo do poluente). A relocalização de uma rotunda ou turbo-rotunda no interior do corredor, de modo a aumentar o espaçamento em relação a uma interseção a jusante e/ou a montante, levou a uma melhoria das emissões do corredor. Conclui-se também que em condições de elevado tráfego de atravessamento e não uniformemente distribuído entre as vias principais e secundárias, os veículos ao longo de um corredor com rotundas produziram menos emissões (~5%) face a um corredor com semáforos, mas emitiram mais gases (~12%) comparativamente a um corredor de interseções prioritárias. Esta investigação contribuiu para o estado de arte através da análise detalhada dos benefícios e limitações dos corredores de rotundas tanto ao nível geométrico como ao nível operacional. Adicionalmente, estabeleceram-se várias correlações entre variáveis geométricas do corredor (espaçamento), localização das passadeiras e volume de tráfego, o atraso, e emissões de CO2, CO, NOX e HC. Demonstrou-se ainda que a implementação de uma interseção ao longo do corredor com a finalidade de minimizar o CO2 pode não resultar na melhoria de outras variáveis tais como o CO ou NOX. Esta metodologia serve como apoio à decisão e, portanto, permite avaliar o tipo de interseção mais adequado de acordo com as especificidades de cada local.Programa Doutoral em Engenharia Mecânic

Soundscape Generation Using Web Audio Archives

Os grandes e crescentes acervos de áudio na web têm transformado a prática do design de som. Neste contexto, sampling -- uma ferramenta essencial do design de som -- mudou de gravações mecânicas para os domínios da cópia e reprodução no computador. A navegação eficaz nos grandes acervos e a recuperação de conteúdo tornaram-se um problema bem identificado em Music Information Retrieval, nomeadamente através da adoção de metodologias baseadas no conteúdo do áudio.Apesar da sua robustez e eficácia, as soluções tecnológicas atuais assentam principalmente em métodos (estatísticos) de processamento de sinal, cuja terminologia atinge um nível de adequação centrada no utilizador.Esta dissertação avança uma nova estratégia orientada semanticamente para navegação e recuperação de conteúdo de áudio, em particular, sons ambientais, a partir de grandes acervos de áudio na web. Por fim, pretendemos simplificar a extração de pedidos definidos pelo utilizador para promover uma geração fluida de paisagens sonoras. No nosso trabalho, os pedidos aos acervos de áudio na web são feitos por dimensões afetivas que se relacionam com estados emocionais (exemplo: baixa ativação e baixa valência) e descrições semânticas das fontes de áudio (exemplo: chuva). Para tal, mapeamos as anotações humanas das dimensões afetivas para descrições espectrais de áudio extraídas do conteúdo do sinal. A extração de novos sons dos acervos da web é feita estipulando um pedido que combina um ponto num plano afetivo bidimensional e tags semânticas. A aplicação protótipo, MScaper, implementa o método no ambiente Ableton Live. A avaliação da nossa pesquisa avaliou a confiabilidade perceptual dos descritores espectrais de áudio na captura de dimensões afetivas e a usabilidade da MScaper. Os resultados mostram que as características espectrais do áudio capturam significativamente as dimensões afetivas e que o MScaper foi entendido pelos os utilizadores experientes como tendo excelente usabilidade.The large and growing archives of audio content on the web have been transforming the sound design practice. In this context, sampling -- a fundamental sound design tool -- has shifted from mechanical recording to the realms of the copying and cutting on the computer. To effectively browse these large archives and retrieve content became a well-identified problem in Music Information Retrieval, namely through the adoption of audio content-based methodologies. Despite its robustness and effectiveness, current technological solutions rely mostly on (statistical) signal processing methods, whose terminology do attain a level of user-centered explanatory adequacy.This dissertation advances a novel semantically-oriented strategy for browsing and retrieving audio content, in particular, environmental sounds, from large web audio archives. Ultimately, we aim to streamline the retrieval of user-defined queries to foster a fluid generation of soundscapes. In our work, querying web audio archives is done by affective dimensions that relate to emotional states (e.g., low arousal and low valence) and semantic audio source descriptions (e.g., rain). To this end, we map human annotations of affective dimensions to spectral audio-content descriptions extracted from the signal content. Retrieving new sounds from web archives is then made by specifying a query which combines a point in a 2-dimensional affective plane and semantic tags. A prototype application, MScaper, implements the method in the Ableton Live environment. An evaluation of our research assesses the perceptual soundness of the spectral audio-content descriptors in capturing affective dimensions and the usability of MScaper. The results show that spectral audio features significantly capture affective dimensions and that MScaper has been perceived by expert-users as having excellent usability

Correlação de variáveis representativas de segurança rodoviária

Mestrado em Engenharia MecânicaA segurança das infra-estruturas de tráfego é geralmente medida através da contagem do número de acidentes que ocorrem e da gravidade resultante dos mesmos. No entanto, esta técnica não é aplicável em projectos que ainda não foram construídos ou implementados no local. Adicionalmente, as simples contagens de tráfego nem sempre têm em consideração parâmetros que influenciam a segurança rodoviária tais como: geometria da via, volume de tráfego e o comportamento do condutor. Torna-se então necessário aplicar uma metodologia mais prática e eficaz que tenha presente estes factores e neste campo insere-se a micro-simulação, uma área com grande potencial de desenvolvimento. A presente Dissertação propõe-se em estabelecer correlações de medidas representativas para a segurança rodoviária através da avaliação dos níveis de conflito (passagem, retaguarda, mudança de via e total) de uma rotunda da cidade de Aveiro. Para tal, foram usados o modelo de simulação VISSIM para a concepção da rede gráfica e a ferramenta SSAM a fim de identificar a frequência de conflitos e medidas representativas da segurança rodoviária. Assim, seleccionaram-se três períodos do dia, correspondentes a três volumes de tráfego distintos, e estabelecidos vários cenários que tivessem em consideração diferentes parâmetros que influenciam a segurança rodoviária: velocidade máxima de 50 km.h-1 e 40 km.h-1, condução mais agressiva e, ainda, a introdução de peões. Foi ainda avaliada a implementação de um projecto alternativo para o mesmo local e comparados os seus resultados através da realização de testes estatísticos. Foram igualmente validados os dados relativos aos conflitos obtidos em ambos os projectos, com os acidentes baseados em modelos de previsão. Os resultados obtidos demonstraram que não se verificaram diferenças significativas no número de conflitos entre ambos os projectos na generalidade dos cenários analisados, excepto para um volume de tráfego médio, na qual se verificou uma redução dos conflitos no projecto alternativo em 22% e 24% para a velocidade máxima de 50 km.h-1 e uma condução mais agressiva do condutor, respectivamente. No que concerne às medidas representativas, verificaram-se conflitos mais graves na rotunda do estudo de caso, nomeadamente nos volumes de tráfego médios e elevados, cujas diferenças atingiram os 39% para velocidades de circulação mais baixas. O nível de acordo entre os conflitos e a frequência de acidentes foi bom para os conflitos de mudança de via, tendo sido obtidas correlações de 0,91 em todos os cenários analisados.Traffic facilities safety is often measured by counting the number of accidents and the severity levels resulting from them. However, this technique is not applicable to projects that are not yet built or implemented on the site. In addition, the simple traffic counts do not always consider parameters that affect traffic safety, such as geometry, traffic volume and driver behavior. Thus, it is necessary to apply a more practical and effective methodology that incorporates these factors and in this fields it is possible to insert the microsimulation. This Thesis has as main objective to establish correlations of representative measures for the traffic safety through the evaluation of a roundabouts safety in the city of Aveiro. For this purpose, the VISSIM simulation model for network design and SSAM tool to identify the conflicts frequencies (crossing, rear-end, lane change and total) and representative measures of traffic safety were used. Thus, three periods of the day were selected, related to three different traffic volumes and several scenarios were established, in order to consider different parameters that affect the traffic safety. The analyzed scenarios were: a speed limit of 50 km.h-1 and 40 km.h-1, a more aggressive driving and also the presence of pedestrians. The implementation of an alternative project for the same site was also evaluated and the results were compared through statistic tests. The data related to the conflicts obtained in both projects were validated with the accidents based in crashes prediction models. The obtained results demonstrated that there were no significant differences in the number of conflicts between both projects, except for a medium traffic volume, in which there was a reduction of conflicts in the alternative project by 22% and 24% for the maximum speed of 50 km.h-1 and a more aggressive driving, respectively. Regarding the representative measures, there were more serious conflicts in the roundabout of the case study, mainly for the medium and high traffic volumes, whose differences reached 39% for lower traffic speeds. The level of agreement between the conflict and crashes frequencies was good; correlations of 0.91 in all scenarios have been obtained for the lane change conflicts

Information Management for Smart and Sustainable Mobility

The main objective of this work is to present a modular platform to manage traffic information for smart mobility. The management and collection of dynamic data is a challenging process especially in the context of low penetration of floating car data (FCD) and limited availability of traffic monitoring stations. In this work, three different road segments of a European medium-sized city were selected to collect vehicle dynamic data over multiple scenarios of traffic demand. Simultaneously, traffic volumes were recorded in real time. The main objective of this pilot experiment was to assess how it would be possible to read and predict traffic congestion and emissions levels with limited information and how data from multiple sources should be managed in order to correlate and deal with this information in real time. It was possible to correlate simultaneously multiple data set such as congestion values, specific vehicle power (VSP) mode distribution, Google traffic data and emission. Preliminary findings suggest that in urban arterials travel time and congestion levels can be reliable indicators for estimating emissions in real time. In sections of rural arterials, the estimation of real-time traffic performance is more complex. Key issues towards the implementation of a prototyping platform in an urban context are also discusse

Weld lines in extrusion: Understanding the role of the flow conditions

This work reports the implemen tation and verification of a new so lver in OpenFOAM® open source computational library, able to cope w ith integral viscoelastic models based on the integral upper-convected Maxwell model. The code is verified through the comparison of its predictions with anal ytical solutions and numerical results obtained with the differential upper-convected Maxwell modelCAPES, FCT projects PEsT-C/CTM/LA0025/2013, PTDC/MAT/121185/2010 and FEDE

Barreiras para a prática de atividade física em pessoas com deficiência visual

Este estudo teve como objetivo avaliar as barreiras para a prática de atividade física em pessoas com deficiência visual. Foi aplicado um questionário específico por telefone a 114 pessoas (moradores do Distrito Federal-Brasil) com deficiência visual pouco ativas. Destacam-se várias barreiras, como problemas com as calçadas, falta de instalações/espaços apropriados, falta de políticas de apoio das entidades públicas, necessidade de guia, falta de oferta de atividades por instituições especializadas e falta de condicões de segurança das instalações físicas para evitar acidentes. Devem ser implantadas medidas apropriadas que ajudem a remover ou diminuir o impacto das principais barreiras apontadas pelos participantes, de modo a promover a saúde e o bem-estar dessa população

Sitagliptin prevents aggravation of endocrine and exocrine pancreatic damage in the Zucker Diabetic Fatty rat - focus on amelioration of metabolic profile and tissue cytoprotective properties

BACKGROUND: The purpose of this study was to investigate some of the possible mechanisms underlying the protective effects of a dipeptidyl peptidase IV (DPP-IV) inhibitor, sitagliptin, on pancreatic tissue in an animal model of type 2 diabetes mellitus (T2DM), the Zucker Diabetic Fatty(ZDF) rat, focusing on glycaemic, insulinic and lipidic profiles, as well as, on apoptosis, inflammation, angiogenesis and proliferation mediators. METHODS: Male obese diabetic ZDF (fa/fa) rats, aged 20 weeks, were treated with sitagliptin (10 mg/kg bw/day) during 6 weeks and compared to untreated diabetic and lean control littermates. Metabolic data was evaluated at the beginning and at the end of the treatment, including glycaemia, HbA1c, insulinaemia, HOMA-beta and TGs. Endocrine and exocrine pancreas lesions were assessed semiquantitatively by histopathological methods. Pancreas gene (mRNA) and protein expression of mediators of apoptotic machinery, inflammation and angiogenesis/proliferation (Bax, Bcl2, IL-1β, VEGF, PCNA and TRIB3) were analyzed by RT-qPCR and/or by immunohistochemistry. RESULTS: Sitagliptin treatment for 6 weeks (between 20 and 26 week-old) was able to significantly (p < 0.001) ameliorate all the metabolicparameters, by preventing the increase in blood glucose and in serum TGs contents (16.54% and 37.63%, respectively, vs untreated), as well as, by preventing the decrease in serum insulin levels and in the functional beta cells capacity accessed via HOMA-beta index (156.28% and 191.74%, respectively, vs untreated). Sitagliptin-treated diabetic rats presented a reduced pancreas Bax/Bcl2 ratio, suggestive of an antiapoptotic effect; in addition, sitagliptin was able to completely reduce (p < 0.001) the pancreas overexpression of IL-1β and TRIB3 found in the untreated diabeticanimals; and promoted a significant (p < 0.001) overexpression of VEGF and PCNA. CONCLUSION: In this animal model of obese T2DM (the ZDF rat), sitagliptin prevented β-cell dysfunction and evolution of pancreatic damage. The protective effects afforded by this DPP-IV inhibitor may derive from improvement of the metabolic profile (viewed by the amelioration of glucose and TGs levels and of insulin resistance) and from cytoprotective properties, such as antiapoptotic, anti-inflammatory, pro-angiogenic and pro-proliferative.The Portuguese Foundation for Science and Technology (FCT) through the projects PEst-C/SAU/UI3282/2013 and PEst-OE/CED/UI4016/2014, and the Center for Studies in Education, Technologies and Health (CI&DETS) and PROTEC grant by the Polytechnic Institute of Viseu (IPV

Statistical and semi-dynamical road traffic noise models comparison with field measurements

The need for road traffic noise monitoring is growing in urban areas due to the growth of vehicles number and to the consequent increase of risk for human health. Noise measurements cannot be performed everywhere, or even in a large number of sites, because of high costs and time consumption. For this reasons, Road Traffic Noise predictive Models (RTNMs) can be implemented to estimate the noise levels at any distance, knowing certain parameters needed as input of the RTNM. In this paper, the main statistical RTNMs are presented, together with the implementation of two innovative and advanced models: the EU suggested model (CNOSSOS-EU) and a research model presented by Quartieri et al. (2010). These models will be compared with noise measurements performed in different sites and with different traffic conditions, in order to avoid bias from geometry or other features of the area under study. The main conclusion is that the application of innovative models and the inclusion of dynamical information about traffic flow, will lead to better results with respect to statistical models

Fixation of the short-term central venous catheter. A comparison of two techniques

Purpose: To compare the fixation of the central venous catheter (CVC) using two suture techniques. Methods: A clinical, analytical, interventional, longitudinal, prospective, controlled, single-blind and randomized study in adult, intensive care unit (ICU) patients. After admission and indication of CVC use, the patients were allocated to the Wing group (n = 35, catheter fixation with clamping wings and retainers) or Shoelace group (n = 35, catheter fixation using shoelace cross- tied sutures around the device). Displacement, kinking, fixation failure, hyperemia at the insertion site, purulent secretion, loss of the device, psychomotor agitation, mental confusion, and bacterial growth at the insertion site were evaluated. Results: Compared with the Wing group, the Shoelace group had a lower occurrence of catheter displacement (n = 0 versus n = 4p = 0.04), kinking (n = 0 versus n = 8p = 0.001), and fixation failure (n = 2 versus n = 8p = 0.018). No significant difference was found in bacterial growth (n = 20 versus n = 14p = 0.267) between groups. Conclusion: The Shoelace fixation technique presented fewer adverse events than the Wing fixation technique.Univ Vale Sapucai UNIVAS, Profess Masters Program Appl Hlth Sci, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Profess Masters Program Appl Hlth Sci, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Hosp Clin Samuel Libanio, Dept Cardiac Surg, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Dept Biostat, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Res Lab, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Hosp Clin Samuel Libanio, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Hosp Clin Samuel Libanio, Intens Care Dept, Pouso Alegre, MG, BrazilUniv Vale Sapucai, Pouso Alegre, MG, BrazilUniv Fed São Paulo UNIFESP, Div Plast Surg, São Paulo, BrazilUniv Fed São Paulo UNIFESP, Div Plast Surg, Dept Surg, São Paulo, BrazilUniv Fed São Paulo UNIFESP, Div Plast Surg, São Paulo, BrazilUniv Fed São Paulo UNIFESP, Div Plast Surg, Dept Surg, São Paulo, BrazilWeb of Scienc