Andreia Hall

Andreia Hall
University of Aveiro | UA · Department of Mathematics

About

90
Publications
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1,226
Citations

Publications

Publications (90)
Article
Full-text available
Purpose A comprehensive protocol to evaluate voice quality can support a full characterisation of voice disorders and be used to plan voice interventions. The purpose of this study was to develop and validate a standardised protocol for voice assessment, contributing with a comprehensive and valuable tool for clinician practice and research. Metho...
Chapter
Forest fires are becoming a more common occurrence in Portugal as well as worldwide. To extinguish or reduce them more quickly and effectively, it is crucial to understand how they spread. This paper presents a study and a model that shows how wildfires spread, assuming the forest can be represented by a graph, where the nodes correspond to forest...
Article
Full-text available
This study focuses on the impact of Alzheimer’s Disease on language, namely the impact in the context of the use of the null subject. We analysed the productions of a group of twelve Alzheimer’s patients and a control group with the same dimension, when reading three types of sentences: One clause with simple tense; one clause with complex tense; t...
Article
This work intends to disseminate a didactic experience in mathematics, in times of pandemic, in an emergency remote teaching situation, at the Portuguese School of Cape Verde, using the Desmos digital platform. The topic addressed was the study of the volume of geometric solids. The main objective was to contribute to the learning of mathematical c...
Preprint
Full-text available
Com este estudo pretendemos conhecer melhor o impacto da Doença de Alzheimer (DA) na linguagem, mais concretamente o impacto no contexto da utilização do sujeito nulo. Analisamos as produções de doze pessoas com DA e de um grupo de controlo com a mesma dimensão, em tarefas de leitura de três tipos de frases: Simples com verbo em tempo simples; simp...
Article
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After five centuries of Muslim presence in Portugal, it would be unthinkable to assume that, apart from the naming of regions, towns, and villages (Algarve, Ourém, Alcabideche), Islamic culture has not left its mark on Portuguese society. It is not possible to ignore the impact of Islamic art on Portuguese art and architecture, especially in decora...
Article
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Symmetry and antisymmetry are resources used by humans since pre-historic times in their artistic creations. In this work we start by introducing antisymmetry and the 17 possible asso- ciated groups. We then present some counts of friezes, built with a particular module, the Truchet tile, which is itself antisymmetric. These counts take into consid...
Article
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In this work we explore the presence of antisymmetry in Portuguese ceramic tile facades, showing examples from different styles and different antisymmetry groups. We further present some experiments with school children who explored symmetry and antisymmetry in a creative way. Children used a particular tile design, the Truchet tile, to create spec...
Article
In the last few decades, technology has advanced in multiple fields, including Education. Some of its benefits include improving student performance and motivation, fostering active learning and tracking student progress. Game-based learning platforms, like Kahoot!, can be used for reviewing content and motivating students for learning. The partici...
Article
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Awake brain surgery, combined with neurophysiological evaluation and intraoperative mapping, is one of the preferential lines of treatment when approaching low-grade gliomas. Speech and language assessment is used while applying Direct Electrical Stimulation (DES) and during the resection of a lesion/tumour, as it allows to establish related eloque...
Conference Paper
The Mathematical Circus project was created in 2011 by the LUDUS association with the main goal of promoting the interest and motiva- tion for learning mathematics. The Mathematical Circus team performs mathematical magic shows where complementary skills are merged to produce a high intervention capacity within a wide geographical range in Portugal...
Article
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Purpose This article reports on the effectiveness of a novel tablet-based approach to phonological intervention and compares it to a traditional tabletop approach, targeting children with phonologically based speech sound disorders (SSD). Method Twenty-two Portuguese children with phonologically based SSD were randomly assigned to 1 of 2 intervent...
Article
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Background: The appropriate use of language in context depends on the speaker’s pragmatic language competencies. A coding system was used to develop a specific and adult-focused self-administered questionnaire to adults who stutter and adults who do not stutter, The Assessment of Language Use in Social Contexts for Adults, with three categories: pr...
Article
In 1704, the French priest Sébastien Truchet published a paper where he explored and counted patterns made up from a square divided by a diagonal line into two coloured parts, , now known as a Truchet tile. A few years later, Father Dominique Doüat continued Truchet's work and published a book in 1722 containing many more patterns and further count...
Article
We investigated Portuguese physiotherapy students' and physiotherapists' (1) perceptions of cardiorespiratory physiotherapy (CRP); (2) factors that influenced their decision to pursue a career in CRP; and (3) suggestions to develop CRP. Online surveys were disseminated to final year students and physiotherapists. A number of 189 students (mean age...
Article
Full-text available
The aim of this study was to develop and content validate specific speech and language intervention picture cards: The Letter-Sound (L&S) cards. The present study was also focused on assessing the influence of these cards on letter-sound correspondences and speech sound production. An expert panel of six speech and language therapists analysed and...
Article
Full-text available
Purpose: There is a need to develop letter knowledge assessment tools to characterise the letter knowledge in Portuguese pre-schoolers and to compare it with pre-schoolers from other countries, but there are no tools for this purpose in Portugal. The aim of this paper is to describe the development and validation procedures of the Prova de Avaliaçã...
Article
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Purpose: To develop the pediatric Automatic Phonological Analysis Tools (APAT) and to estimate inter and intrajudge reliability, content validity, and concurrent validity. Method: The APAT were constructed using Excel spreadsheets with formulas. The tools were presented to an expert panel for content validation. The corpus used in the Portuguese st...
Chapter
Full-text available
Several methods have been proposed for the perceptual evaluation of voice quality, but the GRBAS and Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scales are the most widely used and recommended as part of standardised voice evaluation protocols. In this study, cross-cultural adaptation and translation of the GRBAS (the first translati...
Chapter
Full-text available
A new open access resource called Advanced Voice Function Assessment Databases (AVFAD) was developed, based on a sample of 709 individuals (346 clinically diagnosed with vocal pathology and 363 with no vocal alterations) recruited in Portugal. All clinical conditions were registered according to the Classification Manual of Voice Disorders-I. Parti...
Article
Background: Negative public attitudes toward stuttering have been widely reported, although differences among countries and regions exist. Clear reasons for these differences remain obscure. Purpose: Published research is unavailable on public attitudes toward stuttering in Portugal as well as a representative sample that explores stuttering att...
Article
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Inspiratory muscle fatigue may inhibit healthy athletes to achieve maximum performance, compromising blood flow and perfusion on locomotor muscles. Recent studies have showed irregular influence of inspiratory muscle training (IMT) on resting lung function. It was hypothesized that a 4-week IMT protocol would improve pulmonary function of basketbal...
Conference Paper
Full-text available
This study describes the development of an assessment instrument to calculate severity of observable stuttering behaviours based on four speech samples (reading, monologue, dialogue and telephone speech). The samples are collected with a camcorder and analysed with the ELAN program, which allows complex annotations of video and audio signals. Sever...
Conference Paper
Full-text available
Background: In the phonological disorder domain, it is common to observe poor phonological awareness skills and, consequently, a later or deficit literacy learning. As so, it is important that speech and language therapists stimulate early phonological awareness to prevent reading and spelling difficulties in children with phonological disorder. O...
Article
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The goal of this study was to analyse perceptually and acoustically the voices of patients with Unilateral Vocal Fold Paralysis (UVFP) and compare them to the voices of normal subjects. These voices were analysed perceptually with the GRBAS scale and acoustically using the following parameters: mean fundamental frequency (F0), standard-deviation of...
Conference Paper
Full-text available
In this study the relative fundamental frequency (RFF) of healthy speakers (N=24) and speakers with voice disorders (vocal nodules N=9; Reinke's edema N=15) and its relation with laryngeal tension, were analysed. Ten VCV sequences from a phonetically balanced text were selected to calculate RFF values, and vowel [a] was used to estimate the mean fu...
Conference Paper
Full-text available
The development of an assessment procedure of pragmatic language competencies in adults is described. The instrument, its content validity, and the psychometric data obtained from a pilot study are presented. The Assessment of Language Use in Social Contexts for Adults (ALUSCA) is a specific instrument developed to assess pragmatic language compete...
Article
Full-text available
There is no standard phonetically balanced short passage for Portuguese research and clinical practice. This paper presents results of a novel analysis of 'The North Wind and the Sun' (NWS) passage that aims to determine if it is phonetically balanced for European Portuguese (EP) and Brazilian Portuguese (BP), based on new transcriptions resulting...
Article
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This study investigates the nature of phonological impairment in 20 pre- and early school Portuguese children with phonologically based Speech Sound Disorders (SSD). The phonological profile of these children was compared with the performance of 232 younger typically developing (TD) controls. Results showed differences in phonological acquisition o...
Article
Background: Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based abs...
Article
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This study identifies predictors and normative data for quality of life (QOL) in a sample of Portuguese adults from general population. A cross-sectional correlational study was undertaken with two hundred and fifty-five (N = 255) individuals from Portuguese general population (mean age 43 years, range 25-84 years; 148 females, 107 males). Particip...
Article
Background/aims: To design and standardize the Preschool Language Test (Teste de Linguagem-Avaliação da Linguagem Pré-Escolar, TL-ALPE) which assesses European Portuguese (EP)-speaking children's receptive and expressive language abilities. Methods: To standardize TL-ALPE, data was collected on 817 EP-speaking children aged 3 years and 0 months...
Article
Objective: Studies on the late acquisition of morphosyntax in European Portuguese (EP)-speaking children are relatively scarce in the literature. The purpose of this paper is to report data on the morphosyntactic domain from typically developing children. The present investigation focused on differences in morphosyntactic performance according to...
Article
Background: The effectiveness of two treatment approaches (phonological therapy and articulation therapy) for treatment of 14 children, aged 4;0-6;7 years, with phonologically based speech-sound disorder (SSD) has been previously analysed with severity outcome measures (percentage of consonants correct score, percentage occurrence of phonological...
Article
In Portugal, the routine clinical practice of speech and language therapists (SLTs) in treating children with all types of speech sound disorder (SSD) continues to be articulation therapy (AT). There is limited use of phonological therapy (PT) or phonological awareness training in Portugal. Additionally, at an international level there is a focus o...
Article
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Objective: To develop and standardize a phonetic-phonological test (Teste Fonético-Fonológico-Avaliação da Linguagem Pré-Escolar, TFF-ALPE) for the assessment of European-Portuguese (EP) children's articulation and phonological abilities. Patients and methods: In order to standardize TFF-ALPE, 768 children aged 3;0-6;11 participated in this stud...
Conference Paper
Full-text available
Background: Improving Quality of Life (QOL) is the ultimate goal of aphasia therapy. Understanding clients' perspectives on the impact of disability in their lives is crucial in determining therapy approaches focused on clients' real needs. QOL measures elicit clients' perspectives in a systematic manner. Many applications of QOL measures in aphasi...
Article
In this work we study the limiting distribution of the maximum term of periodic integer-valued sequences with marginal distribution belong- ing to a particular class where the tail decays exponentially. This class does not belong to the domain of attraction of any max-stable distribution. Ne- vertheless, we prove that the limiting distribution is m...
Article
Full-text available
There is an urgent need to develop new outcome measures for respiratory therapy, to evaluate its effectiveness. Adventitious sounds generated from the lungs (crackles and wheezes), can now be quantified and characterized objectively with computer technology. To our knowledge, this is the first reported study designed to assess any change in lung cr...
Chapter
Full-text available
One of the most important clinical challenges in patients with severe brain damage is to estimate different aspects of their actual state of consciousness and, in particular, their residual conscious perception of the environment. Different methods have been developed to quantify the preservation of responses in the ascending sensory systems and th...
Conference Paper
Full-text available
O poliqueta Diopatra neapolitana, é intensivamente explorado para utilização de isco para a pesca desportiva/recreativa. Neste trabalho reportamos as estimativas da produção da mariscagem de D. neapolitana capturada no Canal de Mira, em dois anos distintos (2001/2002 e 2007/2008), estabelecendo uma correspondência entre o volume das capturas, as co...
Article
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This study focuses on the temporal analysis of stops /p b t d k ɡ/ and devoicing analysis of voiced stops /b d ɡ/ produced in different word positions by six native speakers of European Portuguese. The study explores acoustic properties related to voicing. The following acoustic properties were measured: voice onset time (VOT), stop duration, closu...
Article
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This paper aims to analyze the extremal properties of integer-valued moving average sequences obtained as discrete analogues of conventional moving averages replacing scalar multiplication by binomial thinning. In particular, we consider the case in which the scalar coefficients are replaced by random coefficients since in real applications the thi...
Article
Let {Xn} be a stationary sequence with marginal distribution in the domain of attraction of a max-semistable distribution. This includes all distributions in the domain of attraction of any max-stable distribution and also other distributions like some integer-valued distributions with exponential type tails such as the Negative Binomial case. We c...
Article
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In this paper, we investigate the extremal properties of randomly sub-sampled sta-tionary sequences. Motivation comes from the need to account for the effect of missing values on the analysis of time series and the comparison of schemes for monitoring systems with breakdowns or systems with automatic replacement of devices in case of failures.
Article
For a sequence of independent, identically distributed random variables any limiting point process for the time normalized exceedances of high levels is a Poisson process. However, for stationary dependent sequences, under general local and asymptotic dependence restrictions, any limiting point process for the time normalized exceedances of high le...
Article
We consider several integer-valued stationary models of MA and max-AR type and study the limiting distribution of the maximum term after appropriate normalization. In particular, we consider marginal distributions which do not belong to the domain of attraction of any extreme value distribution but exhibit a quasi-stable limiting behavior in the se...
Article
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Several articles related to the "School of Extremes" in Portugal are put together
Article
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This paper aims to analyze the extremal properties of periodic integer-valued se-quences with marginal distribution belonging to a particular class defined by Anderson [1970. J. Appl. Probab. 7, 99–113] where the tail decays exponentially. An expression for calculating the extremal index of sequences satisfying certain local conditions, similar to...
Chapter
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The semi-parametric estimation of this enchanted prince, the extremal index, has also been cursed, and endures similar problems to those appearing in the estimation of his older brother, the tail index: increasing bias as the threshold decreases and high variance for high thresholds. Given a sample, how may we get information on this prince? May co...
Article
Let {X n } be a stationary sequence subject to failures, meaning that some of the variables will be either withdrawn or somehow replaced. We discuss some extremal properties of three different failure models assuming that initially {X n } has an extremal index and satisfies appropriate dependence conditions. Special care is taken whenever X n is in...
Presentation
Full-text available
The extremal index is a parameter of extreme events related to the clustering of exceedances of high thresholds. In the semi-parametric estimation of this parameter we have to cope with problems similar to the ones appearing in the estimation of the tail index (related to the tail heaviness): increasing bias, as the threshold decreases and a high v...
Article
In this note we present a study of the extremal properties of a particular moving average count data model introduced by McKenzie (1986) [Auto regressive-moving-average processes with negative binomial and geometric marginal distribution. Adv. Appl. Probab. 18, 679-705]. After verifying appropriate dependence conditions, we show that the distributi...
Preprint
Full-text available
For a sequence of independent, identically distributed random variables any limiting point process for the time normalized exceedances of high levels is a Poisson process. However, for stationary dependent sequences, under general local and asymptotic dependence restrictions, any limiting point process for the time normalized exceedances of high le...
Article
Full-text available
Bait digging for recreational and commercial fishing is widely practiced and economically significant. Since polychaetes often form part of the diets of several demersal species they are commonly used as fresh bait by sports and professional fishermen. The objectives of this paper are to quantify the annual bait digging of harvest Diopatra neapolit...
Conference Paper
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O príncipe extremal em 3 actos: (1) Apresentação informal (Andreia Hall); (2) Eu, formalista me confesso (Helena Ferreira); (3) Desenvolvimentos computacionais: a moderna extensão do reino da fantasia ?.. (Ivette Gomes).
Conference Paper
Full-text available
In the semi-parametric estimation of the extremal index θ (the Prince of our history) we have to cope with problems similar to the ones appearing in the estimation of his old brother, the tail index γ: increasing bias, as the threshold decreases and a high variance for high thresholds. Given a sample, how may we get information on θ? Is it true tha...
Presentation
Full-text available
In the semi-parametric estimation of the extremal index θ (the Prince of our history), we have to cope with problems similar to the ones appearing in the estimation of his old brother, the tail index: increasing bias, as the threshold decreases and a high variance for high thresholds. Given a sample, how may we get information on θ? Is it true that...
Conference Paper
Full-text available
Whenever we need to perform a statistical analysis of extreme values for stationary data, we are immediately confronted with at least two primary parameters of rare events, which need to be suitably estimated on the basis of a given sample: the tail index and the extremal index. The tail index is directly related to the weight of the right tail of...
Conference Paper
Full-text available
Para alguns modelos dependentes, o estimador de Hill constitui um sério candidato para estimador do índice de cauda, uma vez que é um estimador consistente em diversas situações de dependência, que se caracterizam através de um parâmetro adicional, o índice extremal. Os modelos de médias móveis com distribuições marginais de variação regular são um...
Chapter
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In this paper we compare several estimators for the tail index (γ > 0) in dependent stationary sequences, characterized by an extremal index θ which takes values within a range from zero to one: when it is near one we have exceedances appearing in an "almost" isolated way as it happens with independence; when it takes values next to zero we have cl...
Article
Full-text available
Let {Xk} be a stationary moving average sequence of the form Xk = g( k ):\mathbbN\text0 ® \mathbbN\text0 g{\left( k \right)}:\mathbb{N}_{{\text{0}}} \to \mathbb{N}_{{\text{0}}} be a strictly increasing sequence with a periodic pattern of the form g(k + I) = g(k) + M for some fixed integers I and M verifying 1 I M. Define Yk = Xg(k) as the genera...
Article
In this paper we study the limiting distribution of the maximum term of non-negative integer- valued moving average sequences of the form Xn ¼ P 1 ¼� 1 � iZni where {Zn} is an iid sequence of non- negative integer-valued random variables with exponential type tails of the form 1 � Fn ðÞ �Kn � 1 þ � ðÞ � n when n !1 ;� 2 R; K ;� >0; and ) denotes bi...
Conference Paper
Full-text available
Neste trabalho estamos interessados na comparação, via técnicas de Monte-Carlo, de um conjunto de estimadores do índice de cauda (γ > 0), em estruturas dependentes estacionárias com um índice extremal θ a variar desde valores próximos de um (em que as excedências de níveis elevados ocorrem de forma "quase" isolada) até valores próximos de zero, sit...
Conference Paper
Full-text available
The performance of stochastic optimisers can be assessed experimentally on given problems by performing multiple optimisation runs, and analysing the results. Since an optimiser may be viewed as an estimator for the (Pareto) minimum of a (vector) function, stochastic optimiser performance is discussed in the light of the criteria applicable to more...
Article
We present a statistical study of the distribution of the objective value of solutions (outcomes) obtained by stochastic optimizers. Our results are based on three optimization procedures: random search and two evolution strategies. We study the fit of the outcomes to an extreme value distribution, namely the Weibull distribution through parametric...
Article
Let {Xk} be a non-negative integer-valued stationary moving average sequence and define Yk=XTk as the sub-sampled series at a fixed integer interval T>1. We look at the limiting distribution of sample maxima of {Yk} and the corresponding extremal index.
Conference Paper
Full-text available
Whenever studying extreme value theory we see that a lot of work has been done in the field of stationary data, a type of data arising frequently in the most diverse practical situations. When we are dealing with dependent data, we find a parameter, the so-called extremal index, that gives us an indication on the degree of that dependence, with an...
Article
The paper presents new characterizations of the integer-valued moving average model. For four model variants we give moments and probability generating functions. Yule-Walker and conditional least squares estimators are obtained and studied by Monte Carlo simulation. A new generalized method of moment estimator based on probability generating funct...
Article
In this paper we study the limiting distribution of the maximum term of non-negative integer-valued moving average sequences of the form X n = i = – i Z n – i where { Z n} is an iid sequence of non-negative integer-valued random variables with regularly varying tails, iZ n–i denotes binomial thinning. Several models are considered allowing dif...
Article
In this paper we consider a stationary sequence of discrete random variables with marginal distribution H(x), obtained by a simple transformation from the max-AR(1) sequence considered by Alpuim (1989). Because discrete distributions impose severe restrictions on the convergence of the normalized maxima to an extreme value distribution, it is seen...
Article
Mathematics play an important role in quilt making. Tiling, symmetry, fractals, rep-tiles and Voronoi diagrams are just a few of many mathematical concepts that can be used and explored in patchwork. In this talk we shall present some quilt examples that use mathematical models.

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