Efficient Estimation of the Parameter Path in Unstable Time Series Models

The paper investigates asymptotically efficient inference in general likelihood models with time varying parameters. Parameter path estimators and tests of parameter constancy are evaluated by their weighted average risk and weighted average power, respectively. The weight function is proportional to the distribution of a Gaussian process, and focusses on local parameter instabilities that cannot be detected with certainty even in the limit. It is shown that asymptotically, the sample information about the parameter path is efficiently summarized by a Gaussian pseudo model. This approximation leads to computationally convenient formulas for efficient path estimators and test statistics, and unifies the theory of stability testing and parameter path estimation.Time Varying Parameters; Non-linear Non-Gaussian Smoothing; Weighted Average Risk; Weighted Average Power; Posterior Approximation; Contiguity

Numerical integration of the incrementally non-linear, zero elastic range, bounding surface plasticity model for sand

SANISAND-Z is a recently developed plasticity model for sands with zero purely elastic range in stress space within the framework of Bounding Surface (BS) plasticity. As a consequence of zero elastic range the plastic strain increment direction, and consequently the elastic-plastic moduli fourth order tensor depends on the direction of the stress increment, rendering the model incrementally non-linear and intrinsically implicit. An iterative algorithm based on the Backward Euler method is presented to solve the non-linear system of ordinary differential equations. A non-traditional consistency condition based on the plastic multiplier is introduced as a core element of the system. A thorough analysis of the stability and accuracy of the algorithm is presented based on error estimation. The proposed integration scheme allows the use of SANISAND-Z framework in Finite Element Analysis

Incident detection using data from social media

This is an accepted manuscript of an article published by IEEE in 2017 IEEE 20th International Conference on Intelligent Transportation Systems (ITSC) on 15/03/2018, available online: https://ieeexplore.ieee.org/document/8317967/citations#citations The accepted version of the publication may differ from the final published version.© 2017 IEEE. Due to the rapid growth of population in the last 20 years, an increased number of instances of heavy recurrent traffic congestion has been observed in cities around the world. This rise in traffic has led to greater numbers of traffic incidents and subsequent growth of non-recurrent congestion. Existing incident detection techniques are limited to the use of sensors in the transportation network. In this paper, we analyze the potential of Twitter for supporting real-time incident detection in the United Kingdom (UK). We present a methodology for retrieving, processing, and classifying public tweets by combining Natural Language Processing (NLP) techniques with a Support Vector Machine algorithm (SVM) for text classification. Our approach can detect traffic related tweets with an accuracy of 88.27%.Published versio

Traffic event detection framework using social media

This is an accepted manuscript of an article published by IEEE in 2017 IEEE International Conference on Smart Grid and Smart Cities (ICSGSC) on 18/09/2017, available online: https://ieeexplore.ieee.org/document/8038595 The accepted version of the publication may differ from the final published version.© 2017 IEEE. Traffic incidents are one of the leading causes of non-recurrent traffic congestions. By detecting these incidents on time, traffic management agencies can activate strategies to ease congestion and travelers can plan their trip by taking into consideration these factors. In recent years, there has been an increasing interest in Twitter because of the real-time nature of its data. Twitter has been used as a way of predicting revenues, accidents, natural disasters, and traffic. This paper proposes a framework for the real-time detection of traffic events using Twitter data. The methodology consists of a text classification algorithm to identify traffic related tweets. These traffic messages are then geolocated and further classified into positive, negative, or neutral class using sentiment analysis. In addition, stress and relaxation strength detection is performed, with the purpose of further analyzing user emotions within the tweet. Future work will be carried out to implement the proposed framework in the West Midlands area, United Kingdom.Published versio

A characterization of almost continuity and weak continuity

summary:It is well known that a function $f$ from a space $X$ into a space $Y$ is continuous if and only if, for every set $K$ in $X$ the image of the closure of $K$ under $f$ is a subset of the closure of the image of it. In this paper we characterize almost continuity and weak continuity by proving similar relations for the subsets $K$ of $X$

Modelling of undrained shearing of soft natural clays

stress-strain response of soft natural clays is characterised by anisotropy, destructuration and rate-dependency. An accurate constitutive description of these materials should take into consideration all of the characteristics above. In this paper, two constitutive models for soft soils, namely the SCLAY1S and Creep-SCLAY1S models are used to simulate the undrained response of two soft natural clays, Gothenburg clay from Sweden and Otaniemi clay from Finland. The SCLAY1S model accounts for the effect of inherent and induced anisotropy and destructuration, while the Creep-SCLAY1S accounts also for the creep and rate effects. The model simulations are compared against triaxial compression and extension tests on anisotropically consolidated samples. The results demonstrate the need to incorporate all features represented in the Creep-SCLAY1S model when modelling structured natural clays

AVALIAÇÃO DAS CONDIÇÕES BIOCLIMÁTICAS DA REGIÃO COSTEIRA DO NORDESTE BRASILEIRO: O MUNICÍPIO DE FORTALEZA, CE

A fim de identificar diretrizes que promovam um melhoramento das condições térmicas ao nível do pedestre, o presente estudo analisa o comportamento horário e mensal das variáveis bioclimáticas do município de Fortaleza, cidade litorânea de clima predominantemente quente e úmido durante todo o ano, por meio da aplicação do índice Voto Médio Estimado (PMV). A partir da análise dos resultados, verifica-se que o horário de maior desconforto acontece às 13h durante o Solstício de Verão, gerando extremo estresse fisiológico, com mais de 80% da população insatisfeita. Também é verificada a preferência térmica da população, por meio da aplicação de questionários. Os resultados coincidem com os valores analisados e indicam o sombreamento e a ventilação como recursos necessários à minimização das condições térmicas externas

Numerical investigation of the performance of engineered barriers in controlling stormwater runoff

In this paper, 2-dimensional, hydro-mechanically coupled finite element analyses are conducted to assess the performance of an engineered barrier, constructed from natural geomaterials, aimed at reducing flood risk in urban environments. The barrier consists of an unsaturated compacted soil layer with water holding properties and a drainage layer of a coarse granular material, that acts as a capillary break, and is constructed on top of the natural soil, in this case London clay. The barrier is vegetated so that its water storage capacity is renewed after each rainfall event. Sophisticated boundary conditions are used to simulate the effect of precipitation and evapotranspiration. The evolution of the rainfall infiltration and runoff rate is simulated both for a treated soil column with an engineered barrier and an untreated one consisting solely of in-situ London Clay. The percolation rate of rainfall water from the bottom of the barrier is also estimated. This comparison highlights the effectiveness of the engineered barrier in reducing the risk of fast flooding, in preventing excessive deformations and in protecting underground infrastructure during wetting and drying cycles. The effect of the hydraulic properties and geometry of the barrier is investigated by means of an extensive parametric analysis. Finally, recommendations for the design of barrier systems are made

Corporalidades e construções simbólicas da dor : dimensões narrativas na compreensão, aceitação e vivência da fibromialgia por mulheres moradoras da região metropolitana de Porto Alegre

A Síndrome Fibromialgia é uma doença classificada músculo-esquelética que acomete o corpo como um todo. Seu processo de diagnóstico é particularmente complexo por não haver consenso na comunidade médica, uma vez que não possui evidências clínicas. Neste cenário, a atenção ao relato do paciente é essencial para adentrar outros âmbitos para além da corporalidade física. Este trabalho expõe a necessidade de um olhar para os espaços subjetivos, compreendendo a individualidade de cada paciente como a chave para o acolhimento compreensivo através da narrativa e das dimensões que a compõem. Apresentando pontos de vista de cinco mulheres fibromiálgicas moradoras da região metropolitana de Porto Alegre, pertencentes à faixa etária de 30 a 40 anos de idade. Aqui, a autora também compartilha fragmentos de sua própria história, propondo uma reflexão empática e a disseminação do conhecimento acerca desta enfermidade.Fibromyalgia Syndrome is a muscular-skeleton disease that attacks the entire body. Its diagnosis is particularly complex due the absence of consensus from the medical community, and the shortage of consistent clinical evidence. In this scenario, the attention to the patient's description of the symptoms is essential to access other social dimensions beyond his physical body. This paper exposes the need of a better understanding of the subjective spaces within the individual's journey, comprising the patient's individuality as a key to an sympathetic reception of his narrative and the dimensions that composes it. Introducing the point of view from five women that suffer from Fibromyalgia, residents of the metropolitan region of Porto Alegre, and in the age group of 30 to 40 years old. The author also shares pieces of her own story, proposing an reflecting and empathetic dissemination of the knowledge about the illness