Taming Local Effects in Graph-based Spatiotemporal Forecasting

Spatiotemporal graph neural networks have shown to be effective in time series forecasting applications, achieving better performance than standard univariate predictors in several settings. These architectures take advantage of a graph structure and relational inductive biases to learn a single (global) inductive model to predict any number of the input time series, each associated with a graph node. Despite the gain achieved in computational and data efficiency w.r.t. fitting a set of local models, relying on a single global model can be a limitation whenever some of the time series are generated by a different spatiotemporal stochastic process. The main objective of this paper is to understand the interplay between globality and locality in graph-based spatiotemporal forecasting, while contextually proposing a methodological framework to rationalize the practice of including trainable node embeddings in such architectures. We ascribe to trainable node embeddings the role of amortizing the learning of specialized components. Moreover, embeddings allow for 1) effectively combining the advantages of shared message-passing layers with node-specific parameters and 2) efficiently transferring the learned model to new node sets. Supported by strong empirical evidence, we provide insights and guidelines for specializing graph-based models to the dynamics of each time series and show how this aspect plays a crucial role in obtaining accurate predictions.Comment: Accepted at NeurIPS 202

Graph Deep Learning for Time Series Forecasting

Graph-based deep learning methods have become popular tools to process collections of correlated time series. Differently from traditional multivariate forecasting methods, neural graph-based predictors take advantage of pairwise relationships by conditioning forecasts on a (possibly dynamic) graph spanning the time series collection. The conditioning can take the form of an architectural inductive bias on the neural forecasting architecture, resulting in a family of deep learning models called spatiotemporal graph neural networks. Such relational inductive biases enable the training of global forecasting models on large time-series collections, while at the same time localizing predictions w.r.t. each element in the set (i.e., graph nodes) by accounting for local correlations among them (i.e., graph edges). Indeed, recent theoretical and practical advances in graph neural networks and deep learning for time series forecasting make the adoption of such processing frameworks appealing and timely. However, most of the studies in the literature focus on proposing variations of existing neural architectures by taking advantage of modern deep learning practices, while foundational and methodological aspects have not been subject to systematic investigation. To fill the gap, this paper aims to introduce a comprehensive methodological framework that formalizes the forecasting problem and provides design principles for graph-based predictive models and methods to assess their performance. At the same time, together with an overview of the field, we provide design guidelines, recommendations, and best practices, as well as an in-depth discussion of open challenges and future research directions

Taming Local Effects in Graph-based Spatiotemporal Forecasting

Spatiotemporal graph neural networks have shown to be effective in time series forecasting applications, achieving better performance than standard univariate predictors in several settings. These architectures take advantage of a graph structure and relational inductive biases to learn a single (global) inductive model to predict any number of the input time series, each associated with a graph node. Despite the gain achieved in computational and data efficiency w.r.t. fitting a set of local models, relying on a single global model can be a limitation whenever some of the time series are generated by a different spatiotemporal stochastic process. The main objective of this paper is to understand the interplay between globality and locality in graph-based spatiotemporal forecasting, while contextually proposing a methodological framework to rationalize the practice of including trainable node embeddings in such architectures. We ascribe to trainable node embeddings the role of amortizing the learning of specialized components. Moreover, embeddings allow for 1) effectively combining the advantages of shared message-passing layers with node-specific parameters and 2) efficiently transferring the learned model to new node sets. Supported by strong empirical evidence, we provide insights and guidelines for specializing graph-based models to the dynamics of each time series and show how this aspect plays a crucial role in obtaining accurate predictions

Anwendung des Penetrationsmodells von Chlorid bei der Beurteilung des Zustands beim Brückenmanagement

Although there is a large number of established Bridge Management Systems worldwide, there seems to be a lack of those that utilise the knowledge on material properties and environmental loading. Hence, as a supplement to current practice, the paper examines the use of the chloride ingress model, supported by the International Federation for Structural Concrete, for preliminary assessment in bridge management. The focus is set on analysing application of the model in realistic situations on existing concrete bridges for which the information on material and environmental properties is lacking.Iako se danas diljem svijeta primjenjuju brojni sustavi za gospodarenje mostovima, čini se da ipak nema dovoljno sustava u kojima bi se koristilo znanje o svojstvima materijala i opterećenju iz okoliša. U ovom se radu, kao doprinos sadašnjoj praksi, analizira primjena modela prodora klorida, što podržava Međunarodni savez za betonske konstrukcije, a koristi se za preliminarno ocjenjivanje u okviru gospodarenja mostovima. Prije svega, analizira se primjena modela u realnim situacijama za ocjenu postojećih betonskih mostova za koje ne postoje podaci o materijalima i svojstvima okoliša.Obwohl heute weltweit zahlreiche Brückenmanagementsysteme angewendet werden, scheint es jedoch nicht ausreichend Systeme zu geben, in denen die Kenntnisse über die Materialeigenschaften und die Umweltbelastung angewendet werden. In dieser Abhandlung wird als Beitrag zur aktuellen Praxis die Anwendung des Penetrationsmodells von Chlorid analysiert, was vom Internationalen Verband für Betonkonstruktionen unterstützt wird, und wird als vorläufige Beurteilung im Rahmen des Brückenmanagements angewendet. Zunächst wird die Anwendung des Modells unter realen Bedingungen für die Beurteilung der bestehenden Betonbrücken analysiert, zu denen Daten über die Materialien und die Umwelteigenschaften vorliegen.The authors would like to show their gratitude for the support received during the project “Life – Cycle Assessment for Railway Structures”, funded by the ÖBB-Infrastruktur Bau AG, Vienna. For the support in the analysis of existing standards, authors would like to express special appreciation to Smart Minerals GmbH

Value of information (VoI) for the chloride content in reinforced concrete bridges

The corrosion of reinforcement caused by chloride ingress significantly reduces the length of the service life of reinforced concrete bridges. Therefore, the condition of bridges is periodically inspected by specially trained engineers regarding the possible occurrence of reinforcement corrosion. Their main goal is to ensure that the structure can resist mechanical and environmental loads and offer a satisfactory level of safety and serviceability. In the course of assessment, measuring the chloride content, through which corrosion could be anticipated and prevented, presents a possible alternative to visual inspections and corrosion tests that can only indicate already existing corrosion. It is hard to determine the cost-effectiveness and actual value of chloride content measurements in a simple and straightforward way. Thus, the main aim of the paper was to study the value of newly gained information, which is obtained when a chloride content in reinforced concrete bridges is measured. This value was here analyzed through the pre-posterior analysis of the cost of measurement and repair, taking into account different types of exposure and material properties for a general case. The research focus was set on the initiation phase in which there are no visible damages. A relative comparison of costs is presented, where the cost of possible reactive/proactive repair was compared with the maximum cost of measurement, while the measurement is still cost effective. The analysis showed a high influence of the initial probability of depassivation on the maximum cost of the cost-effective measurement, as well as a nonreciprocal relation of the minimum cost of cost-effective reactive repair with the measurement accuracy.The author would like to acknowledge the financial and educational support from the COST TU 1402 Action (www.cost-tu1402.eu), received through the Training School grant

fib models for modeling of chloride ion ingress and concrete carbonation: Levels of assessment of input parameters

Degradation processes affecting structural materials, such as chloride ion ingress, concrete carbonation, and the subsequent corrosion of reinforcement, are limiting factors for the service life of reinforced concrete structures and/or structural elements. The objective of a structural condition assessment is to determine the current state and estimate the future performance of a structure with a maximum degree of accuracy and a minimum of effort. There is therefore a need for advanced methodologies and predictive deterioration models for the assessment of structures/structural elements over time. In the paper, the focus is on the widely accepted models for modeling of chloride ion ingress into concrete and concrete carbonation process incorporated in the fib Model Code 2010. Three levels of assessment of input parameters are presented, starting with simple quantification based on codes/literature recommendations and progressing to higher levels of assessment using design documentation and visual inspection data, additional on-site measurements, and/or laboratory tests

Clinical variables of preoperative risk in thoracic surgery

CONTEXT: Pulmonary complications are the most common forms of postoperative morbidity in thoracic surgery, especially atelectasis and pneumonia. The first step in avoiding these complications during the postoperative period is to detect the patients that may develop them. OBJECTIVE: To identify risk variables leading to early postoperative pulmonary complications in thoracic surgery. DESIGN: Prospective study. SETTING: Hospital das Clínicas, Faculdade de Ciências Médicas, Universidade Estadual de Campinas. PATIENTS: 145 patients submitted to elective surgery were classified as low, moderate and high risk for postoperative pulmonary complications using a risk assessment scale. PROCEDURES: The patients were followed up for 72 hours after the operation. Postoperative pulmonary complications were defined as atelectasis, pneumonia, tracheobronchitis, wheezing, prolonged intubation and/or prolonged mechanical ventilation. MAIN MEASUREMENTS: Univariate analysis was applied in order to study these independent variables: age, nutritional status, body mass index, respiratory disease, smoking habit, spirometry and surgery duration. Multivariate logistic regression analysis was performed in order to evaluate the relationship between independent and dependent variables. RESULTS: The incidence of postoperative complications was 18.6%. Multivariate logistic regression analysis showed that the variables increasing the chances of postoperative pulmonary complications were wheezing (odds ratio, OR = 6.2), body mass index (OR = 1.15), smoking (OR = 1.04) and surgery duration (OR = 1.007). CONCLUSION: Wheezing, body mass index, smoking and surgery duration increase the chances of postoperative pulmonary complications in thoracic surgeryCONTEXTO: As complicações pulmonares pós-operatórias, principalmente a pneumonia e atelectasia, têm sido freqüentes causas de morbidade nas cirurgias torácicas. Há interesse em se identificar fatores no processo de avaliação pré-operatória que possam, isoladamente ou associados, contribuir para o aparecimento de tais complicações. OBJETIVO: Identificar as variáveis de risco para complicação pulmonar pós-operatórias na cirurgia torácica. TIPO DE ESTUDO: Estudo prospectivo. LOCAL: Hospital das Clínicas da Universidade Estadual de Campinas PARTICIPANTES: 145 pacientes adultos, ambos os sexos, internados para cirurgia torácica eletiva e classificados em baixo, moderado e alto risco para complicação pulmonar pós-operatória utilizando-se uma escala de avaliação de risco. PROCEDIMENTO: Os pacientes foram acompanhados até as 72 horas do pós-operatório e avaliados quanto ao aparecimento de complicações pulmonares pós-operatória, definidas com o aparecimento de atelectasia, pneumonia, traqueobronquite, chiado, intubação ou ventilação mecânica prolongada. VARIÁVEIS ESTUDADAS: A análise univariada foi aplicada no estudo das variáveis independentes idade, estado nutricional, doença respiratória, hábitos tabágicos, espirometria e tempo cirúrgico. A análise dos resultados através da regressão logística multivariada mostrou relação entre as variáveis dependentes e independentes. RESULTADOS: As complicações pulmonares pós-operatórias incidiram sobre 18.6% da amostra. Através da regressão logística multivariada, verificou-se que as variáveis que aumentaram as chances de complicações pulmonar pós-operatórias foram chiado (Odds ratio, OR = 6.2), estado nutricional (OR = 1.15), tabagismo (OR = 1.04) e duração da cirurgia (OR = 1.007). CONCLUSÃO: Chiado, estado nutricional, tabagismo e duração da cirurgia aumentaram a ocorrência de complicações pulmonares pós-operatórias em cirurgia torácica.10711

Gamma prediction models for long-term creep deformations of prestressed concrete bridges

For long-span bridges as well as statically indeterminate frame structures it is essential to implement efficient and realistic prediction models for the long-term processes of concrete creep, shrinkage, and steel relaxation. In order to systematically study the main influential factors in bridge deflection measurements a probabilistic analysis can be per­formed. Due to the associated computational costs such investigations are limited. The predictions based on the highly scattered input parameters are associated with uncertainties. There is interest in alternative prediction models decou­pled from complex analytical and computationally expensive numerical models, using measured structural responses. A gamma process is an example of such an alternative method. This process is suitable for capturing evolving structural response quantities and deterioration mechanisms like crack propagation, corrosion, creep, and shrinkage, as reported in Ohadi and Micic (2011). The objective of this paper is to illustrate the use of gamma process approaches for the pre­diction of the creep and shrinkage performance of prestressed concrete bridges. The presented approaches incorporate uncertainties and make predictions more reliable with the help of structural health monitoring (SHM) data. The creep-shrinkage response of a prestressed box girder bridge serves for the calibration and evaluation of the considered gamma process approaches

Foreign body aspiration in children: clinical aspects, radiological aspects and bronchoscopic treatment

OBJECTIVE: To describe the clinical manifestations and bronchoscopic treatment of foreign body aspiration in children under 14 years of age, correlating the clinical aspects with the bronchoscopic findings. METHODS: A retrospective, descriptive study analyzing data related to children under 14 years of age undergoing bronchoscopy due to clinical suspicion of foreign body aspiration at the State University at Campinas Hospital das Clinicas from January of 2000 to December of 2005. RESULTS: The sample consisted of 69 patients, ranging in age from 8 months to 12 years/7 months (75.4% under 3 years of age), 62.3% of whom were male. The principal complaint was sudden-onset cough (75.4%), auscultation was abnormal in 74%, and dyspnea was observed in 29%. Radiological abnormalities were seen in 88% of the cases. Aspirations were primarily into the right lung (54.8%), and 30.7% of the foreign bodies were of vegetal origin (principally beans and peanuts). In the follow-up period, 29% presented complications (most commonly pneumonia), which were found to be associated with longer aspiration time (p = 0.03). Mechanical ventilation was required in 7 children (10.1%), and multiple bronchoscopies were performed in 5 (7.2%). CONCLUSION: A history of sudden-onset choking and cough, plus abnormal auscultation and radiological findings, characterizes the profile of foreign body aspiration. In such cases, bronchoscopy is indicated. Longer aspiration time translates to a higher the risk of complications. The high prevalence of foreign bodies of vegetal origin underscores the relevance of prevention programs aimed at children younger than 3 years of age.Descrever manifestações clínicas e tratamento broncoscópico da aspiração de corpo estranho em crianças menores de 14 anos de idade, correlacionando com achados broncoscópicos. MÉTODOS: Estudo retrospectivo, descritivo analisando prontuários de todas as crianças menores de 14 anos de idade atendidas no Hospital das Clinicas da Universidade Estadual de Campinas de janeiro de 2000 a dezembro de 2005, submetidas à broncoscopia por suspeita clínica de aspiração de corpo estranho. RESULTADOS: Foram analisados 69 pacientes, com idade entre 8 meses e 12 anos/7 meses (75,4% abaixo de 3 anos), dos quais 62,3% eram do sexo masculino. A principal queixa foi tosse súbita (75,4%). Em 74% dos casos houve alteração de ausculta pulmonar e dispnéia foi observada em 20 crianças (29%). Um total de 88% apresentou alteração radiológica. A aspiração ocorreu predominantemente em pulmão direito (54,8%), com material de origem vegetal, destacando feijão e amendoim (30,7%). Complicações ocorreram em 29% dos pacientes, sendo pneumonia a mais comum, e foram associadas ao tempo maior de aspiração (p = 0,03). Um total de 7 pacientes (10,1%) necessitaram ventilação mecânica, e 5 (7,2%) foram submetidos a mais de uma broncoscopia. CONCLUSÃO: História clínica com início súbito de engasgo e tosse, anormalidades na ausculta pulmonar e na radiografia de tórax caracterizam o quadro clínico de aspiração e são indicativas de broncoscopia. Quanto maior o tempo de aspiração, maior o risco de complicações. A alta prevalência de corpos estranhos de origem vegetal alerta para a necessidade de programas preventivos dirigidos aos menores de 3 anos3427482To describe the clinical manifestations and bronchoscopic treatment of foreign body aspiration in children under 14 years of age, correlating the clinical aspects with the bronchoscopic findings. METHODS: A retrospective, descriptive study analyzing data related to children under 14 years of age undergoing bronchoscopy due to clinical suspicion of foreign body aspiration at the State University at Campinas Hospital das Clinicas from January of 2000 to December of 2005. RESULTS: The sample consisted of 69 patients, ranging in age from 8 months to 12 years/7 months (75.4% under 3 years of age), 62.3% of whom were male. The principal complaint was sudden-onset cough (75.4%), auscultation was abnormal in 74%, and dyspnea was observed in 29%. Radiological abnormalities were seen in 88% of the cases. Aspirations were primarily into the right lung (54.8%), and 30.7% of the foreign bodies were of vegetal origin (principally beans and peanuts). In the follow-up period, 29% presented complications (most commonly pneumonia), which were found to be associated with longer aspiration time (p = 0.03). Mechanical ventilation was required in 7 children (10.1%), and multiple bronchoscopies were performed in 5 (7.2%). CONCLUSION: A history of sudden-onset choking and cough, plus abnormal auscultation and radiological findings, characterizes the profile of foreign body aspiration. In such cases, bronchoscopy is indicated. Longer aspiration time translates to a higher the risk of complications. The high prevalence of foreign bodies of vegetal origin underscores the relevance of prevention programs aimed at children younger than 3 years of ag

Foreign Body Aspiration In Children: Clinical Aspects, Radiological Aspects And Bronchoscopic Treatment.

To describe the clinical manifestations and bronchoscopic treatment of foreign body aspiration in children under 14 years of age, correlating the clinical aspects with the bronchoscopic findings. A retrospective, descriptive study analyzing data related to children under 14 years of age undergoing bronchoscopy due to clinical suspicion of foreign body aspiration at the State University at Campinas Hospital das Clinicas from January of 2000 to December of 2005. The sample consisted of 69 patients, ranging in age from 8 months to 12 years/7 months (75.4% under 3 years of age), 62.3% of whom were male. The principal complaint was sudden-onset cough (75.4%), auscultation was abnormal in 74%, and dyspnea was observed in 29%. Radiological abnormalities were seen in 88% of the cases. Aspirations were primarily into the right lung (54.8%), and 30.7% of the foreign bodies were of vegetal origin (principally beans and peanuts). In the follow-up period, 29% presented complications (most commonly pneumonia), which were found to be associated with longer aspiration time (p = 0.03). Mechanical ventilation was required in 7 children (10.1%), and multiple bronchoscopies were performed in 5 (7.2%). A history of sudden-onset choking and cough, plus abnormal auscultation and radiological findings, characterizes the profile of foreign body aspiration. In such cases, bronchoscopy is indicated. Longer aspiration time translates to a higher the risk of complications. The high prevalence of foreign bodies of vegetal origin underscores the relevance of prevention programs aimed at children younger than 3 years of age.3474-8