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Vehicle tracking using the k-shortest paths algorithm and dual graphs
No full textVehicle trajectory descriptions are required for the development of driving behaviour models and in the calibration of several traffic simulation applications. In recent years, the progress in aerial sensing technologies and image processing algorithms allowed for easier collection of such detailed traffic datasets and multiple-object tracking based on constrained flow optimization has been shown to produce very satisfactory results, even in high density traffic situations. This method uses individual image features collected for each candidate vehicle as criteria in the optimization process. When dealing with poor image quality or low ground sampling distances, feature-based optimization may produce unreal trajectories.
In this paper we extend the application of the k-shortest paths algorithm for multiple-object tracking to the motion-based optimization. A graph of possible connections between successive candidate positions was built using a first level criteria based on speeds. Dual graphs were built to account for acceleration-based and acceleration variation-based criteria. With this framework both longitudinal and lateral motion-based criteria are contemplated in the optimization process. The k-shortest disjoints paths algorithm was then used to determine the optimal set of trajectories (paths) on the constructed graph.
The proposed algorithm was successfully applied to a vehicle positions dataset, collected through aerial remote sensing on a Portuguese suburban motorway. Besides the importance of a new trajectory dataset that will allow for the estimation of new behavioural models and the validation of existing ones, the motion-based multiple-vehicle tracking algorithm allowed for a fast and effective processing using a simple optimization formulation.7-pp3 - 11Vol 1, Issue 1DT / NPTSTransportation Research Procedi
Potential reactivity to alkalis of Portuguese volcanic aggregates for concrete
No full textIn Portugal, volcanic rocks are commonly used as concrete aggregates for concrete in Madeira
and Azores Islands and in a lesser extent in the Mainland. Nonetheless, the information about
the potential alkali-silica reactivity of Portuguese volcanic rocks is rather scarce. In order to
ful ll this lack of information and in the scope of a Portuguese research project, four volcanic
aggregates from the Portuguese Mainland and Madeira Archipelago were investigated. For
this purpose petrographic characterization (polarizing microscopy complemented by bulk
chemical analysis and scanning electron microscopy with energy dispersive detector) along
with expansion laboratory tests were carried out. In this paper, results of the investigation are
presented aiming to establish a possible correlation among the results from the used methods.55-58ppThe authors are thankful to Fundação para a Ciência e Tecnologia (FCT) for the financial support concerning the Project IMPROVE (Ref: PTDC/ECM/115486/2009). The authors afiliated in the CGUP are thankful to FCT for the funding of the Strategic Project Pest-OE/CTE/UI0039/2014. The author V. Ramos is
grateful to FCT towards the financial support of her PhD studies (Ref:SFRH/BD/47893/2008)5DM/NMMUrban Geology, Sustainable Planning and Landscape Exploitatio
The ReAVA project: assessment of the potential alkali-reactivity of volcanic aggregates from Azores Islands
No full textVolcanic rocks have been found to be potentially alkali-reactive in a number of countries,
including Japan, New Zealand, Iceland and Turkey. In order to characterize the potential
reactivity of the volcanic rocks in Azores a project is being carried out, under the support of
the Azores Government: the ReAVA Project—“Characterization of Potential Reactivity of the
Volcanic Aggregates from the Azores Archipelago: Implications on the Durability of Concrete
Structures”. This project comprises mainly: (1) petrographic assessment of the aggregates, (2)
assessment of their performance in expansion tests and (3) site inspection of existing large
concrete structures. This study has also the support of the IMPROVE Project—“Improvement
of Performance of Aggregates in the Inhibition of Alkali-Aggregate Reactions in Concrete”,
aiming to minimize the occurrence of alkali aggregate reaction (AAR) in Portugal. The
Azorean rocks used as aggregates are mainly basalts and some trachytes. The reactivity of this
kind of rocks is usually associated with the presence of volcanic glass, altered minerals and
SiO2 content of the rock. The petrographic examinations of the rocks confirmed that one of the
basaltic samples contains volcanic glass. The occurrence of microcrystalline quartz as a secondary product filling the interstices of the trachyte sample was confirmed by scanning electron microscope. The results of the concrete expansion test RILEM AAR-3 showed an increasing expansion starting on 140 days and continued to grow after 2 years of laboratory testing, but below the limit of 0.05 % recommended for this method.51-54ppThe analyses by SEM/EDS were performed at CEMUP which equipment was funded by the projects REEQ/1062/CTM/2005 and REDE/1512/RME/2005 of Portuguese Foundation for Science and Technology (FCT). The authors also acknowledge the financial support of the FRC under the project M5.2.2/I/05/2011 and FCT under the project PTDC/ECM/15486/2009.5DM/NMMUrban Geology, Sustainable Planning and Landscape Exploitatio
Relatório do levantamento de perfis morfológicos do sistema praia-duna da Costa da Caparica, entre Cova do Vapor e Ribeira Foz do Rego. 10 de outubro de 2014
No full textEste registo pertence ao Repositório Científico do LNECDHA/NP
A gestão de perdas de água
No full text1pArtigo de opinião. Dossiê especial sobre Uso Eficiente de ÁguaNº 184DHA/NESJornal Água & Ambient
Os nossos pequenos mundos domésticos e pessoais: introdução
No full textO mundo doméstico retoma, hoje em dia, uma importância que talvez só tenha tido no mundo antigo, quando habitar e trabalhar profissionalmente se conjugavam, com frequência, nos mesmos espaços de habitar, condição que, entre outros aspetos, tinha exigências específicas de adequada integração e proximidades urbanas; exigências estas que talvez hoje, também, devam ser devidamente reconsideradas.2 fig7 pInfohabitar, Ano X, n.º 468DED/NUTRevista Infohabita
SIMULAÇÃO NUMÉRICA DA INTERAÇÃO DE ONDAS COM UM QUEBRA-MAR POROSO UTILIZANDO O CÓDIGO OPENFOAM
No full textNo presente artigo apresentam-se as simulações numéricas feitas utilizando o código OpenFOAM®, recorrendo à biblioteca porousWaveFoam, para simular a interação de ondas com um quebra-mar poroso. O código numérico resolve as equações VARANS (Volume-Averaged Reynolds-Averaged Navier-Stokes) em regime transitório e utiliza um esquema do tipo VoF (Volume of Fluid) para identificar a superfície livre. O meio poroso é modelado pela equação de Darcy–Forchheimer. Os resultados numéricos são comparados com dados obtidos experimentalmente no Laboratório Nacional de Engenharia Civil (LNEC) para um modelo de quebra-mar à escala 1:30. Foi considerada uma onda incidente regular com 2,19 s de período e 0,083 m de altura. São feitas comparações de elevação de superfície livre para 10 sondas colocadas em diferentes posições ao longo do canal e é apresentada uma análise estatística, de modo a avaliar quantitativamente a diferença entre os resultados numéricos e os experimentais. Constata-se que os resultados numéricos obtidos apresentam valores próximos dos experimentais. As diferenças verificadas são atribuíveis a imprecisões numéricas e ao próprio modelo de meio poroso.1228DHA/NPE201412 a 14 de novembr
Efficiency assessment of the household water use
No full textEste registo pertence ao Repositório Científico do LNECThe aim of the current thesis is the development and testing of a comprehensive methodology to assess the overall households' water use efficiency in indoor domestic water use. This methodology comprises an efficiency evaluation based on efficient patterns, peer comparison and water devices performance. he proposed methodology is composed of three main modules: Module 1. Efficient patterns comparison, Module 2. Peer comparison and Module 3. Evaluation based on performance indices of water devices. The three modules should be applied in a complementary way in order to assess most aspects of water efficiency in the household, but can also be applied independently, as each module returns an individual different type of assessment. The methodology was applied to a case study composed of 43 households, mostly located in the Lisbon urban area and surrounding municipalities, corresponding to approximately 100 persons. All households have extensive measurements and detailed event records of all indoor water uses, and were surveyed to collect information on their socio-demographic characteristics and on the existing water devices in the households (WC, shower, taps, dishwasher and washing machine). The methodology was further tested with an additional small case study carried out with three volunteer consumers. The development of a systematic and detailed methodology for the assessment of domestic consumers’ behaviour both in terms of their own consumption and their level of efficiency relatively to their peers constitutes the main novel contribution of this work. This efficiency assessment allows the identification of potential savings and, thus, the methodology enables the promotion of a more efficient use of water by domestic consumers. Furthermore, it is also useful for the water utilities to optimize the supply systems operation and to improve the quality of service through a better knowledge of consumption profiles.Master of Science Thesis in Environmental Engineering, Instituto Superior Técnico, Universidade de LisboaDHA/NE
Environment and health in children day care centres (ENVIRH) - Study rationale and protocl
No full textBackground: Indoor air quality (IAQ) is considered an important determinant of human health.
The association between exposure to volatile organic compounds, particulate matter, house
dust mite, molds and bacteria in day care centers (DCC) is not completely clear. The aim of this
project was to study these effects.
Methods --- study design: This study comprised two phases. Phase I included an evaluation of
45 DCCs (25 from Lisbon and 20 from Oporto, targeting 5161 children). In this phase, building
characteristics, indoor CO2 and air temperature/relative humidity, were assessed. A children’s respiratory health questionnaire derived from the ISAAC (International Study on Asthma and
Allergies in Children) was also distributed. Phase II encompassed two evaluations and included
20 DCCs selected from phase I after a cluster analysis (11 from Lisbon and 9 from Oporto,
targeting 2287 children). In this phase, data on ventilation, IAQ, thermal comfort parameters,
respiratory and allergic health, airway inflammation biomarkers, respiratory virus infection
patterns and parental and child stress were collected.
Results: In Phase I, building characteristics, occupant behavior and ventilation surrogates were
collected from all DCCs. The response rate of the questionnaire was 61.7% (3186 children).
Phase II included 1221 children. Association results between DCC characteristics, IAQ and
health outcomes will be provided in order to support recommendations on IAQ and children’s
health. A building ventilation model will also be developed.
Discussion: This paper outlines methods that might be implemented by other investigators
conducting studies on the association between respiratory health and indoor air quality at
DCC.
© 2013 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L. All rights
reserved.1213pDED/NAICIRevista portuguesa de pneumologi
Preliminary study of the acoustic behavior concerning an innovative prototype for indoor modular partitioning
No full textThis paper presents a preliminary acoustic study concerning the development of the first prototype of a
patented removable module for interior partitioning. It is a prefabricated, vertical element for division of
interior spaces that does not require the use of gutters or technical support. A set of such modules, linearly
disposed, will create a division, allowing the personalization of any indoor area, including open office spaces,
rooms, among others. The main characteristic that distinguishes this element from the existing solutions
available on the market is that its mobility relies exclusively on a set of integrated bearings at the base of each module. Through an incorporated elevation system, the user can lower the module, move it to the desired position and re-elevate it until pressed against the ledge of the ceiling, making it stable. In this sense, and taking into account its acoustic behavior, several tests were made in the LNEC acoustics lab. Airborne sound insulation tests for different typologies of the prototype were conducted, according to the applicable standards EN ISO 354:2003, EN ISO 717-1:2013 and EN ISO 10140-2:2010. Some important conclusions and analysis of the prototype viability were extracted.8ppSeminário / Melbourne - AustráliaDED/NAIC