Correlative Channel-Aware Fusion for Multi-View Time Series Classification

Multi-view time series classification (MVTSC) aims to improve the performance by fusing the distinctive temporal information from multiple views. Existing methods mainly focus on fusing multi-view information at an early stage, e.g., by learning a common feature subspace among multiple views. However, these early fusion methods may not fully exploit the unique temporal patterns of each view in complicated time series. Moreover, the label correlations of multiple views, which are critical to boost-ing, are usually under-explored for the MVTSC problem. To address the aforementioned issues, we propose a Correlative Channel-Aware Fusion (C2AF) network. First, C2AF extracts comprehensive and robust temporal patterns by a two-stream structured encoder for each view, and captures the intra-view and inter-view label correlations with a graph-based correlation matrix. Second, a channel-aware learnable fusion mechanism is implemented through convolutional neural networks to further explore the global correlative patterns. These two steps are trained end-to-end in the proposed C2AF network. Extensive experimental results on three real-world datasets demonstrate the superiority of our approach over the state-of-the-art methods. A detailed ablation study is also provided to show the effectiveness of each model component

Metaheuristic approaches in biopharmaceutical process development data analysis

Abstract: There is a growing interest in mining and handling of big data, which has been rapidly accumulating in the repositories of bioprocess industries. Biopharmaceutical industries are no exception; the implementation of advanced process control strategies based on multivariate monitoring techniques in biopharmaceutical production gave rise to the generation of large amounts of data. Real-time measurements of critical quality and performance attributes collected during production can be highly useful to understand and model biopharmaceutical processes. Data mining can facilitate the extraction of meaningful relationships pertaining to these bioprocesses, and predict the performance of future cultures. This review evaluates the suitability of various metaheuristic methods available for data pre-processing, which would involve the handling of missing data, the visualisation of the data, and dimension reduction; and for data processing, which would focus on modelling of the data and the optimisation of these models in the context of biopharmaceutical process development. The advantages and the associated challenges of employing different methodologies in pre-processing and processing of the data are discussed. In light of these evaluations, a summary guideline is proposed for handling and analysis of the data generated in biopharmaceutical process development

Testing the equality of a large number of means of functional data

Given k independent samples of functional data, this paper deals with the problem of testing for the equality of their mean functions. In contrast to the classical setting, where k is kept fixed and the sample size from each population increases without bound, here k is assumed to be large and the size of each sample is either bounded or small in comparison to k. A new test is proposed. The asymptotic distribution of the test statistic is stated under the null hypothesis of equality of the k mean functions as well as under alternatives, which allows us to study the consistency of the test. Specifically, it is shown that the test statistic is asymptotically free distributed under the null hypothesis. The finite sample performance of the test based on the asymptotic null distribution is studied via simulation. Although we start by assuming that the data are functions, the proposed test can also be applied to finite dimensional data. The practical behavior of the test for one dimensional data is numerically studied and compared with other tests

Digitizing arquetypal human expereience through physiological signals

The problem of capturing human experience is relevant in many application domains. In fact, the process of describing and sharing individual experience lies at the heart of human culture. This advancement came at a price of losing some of the multidimensional aspects of primary, bodily experience during its projection into the symbolic formThroughout the courses of our lives we learn a great deal of information about the world from other people's experience. Besides the ability to share utilitarian experience such as whether a particular plant is poisonous, humans have developed a sophisticated competency of social signaling that enables us to express and decode emotional experience. The natural way of sharing emotional experiences requires those who share to be co-present during this event. However, people have overcome the limitation of physical presence by creating a symbolic system of representations.Recent research in the field of affective computing has addressed the question of digitization and transmission of emotional experience through monitoring and interpretation of physiological signals. Although the outcomes of this research represent a great step forward in developing a technology that supports sharing of emotional experiences, they do not seem to help in preserving the original phenomenological experience during the aforementioned projection. This circumstance is explained by the fact that in affective computing the focus of investigation has been aimed at emotional experiences which can be consciously evaluated and described by individuals themselves. Therefore, generally speaking, applying an affective computing technique for capturing emotions of an individual is not a deeper or more precise way to project her experience into the symbolic form than asking this person to write down a description of her emotions on a piece of paper. One can say that so far the research in affective computing has aimed at delivering technology that could automate the projection but it has not considered the problem of improving the projection in order to preserve more of the multidimensional aspects of human experience.This dissertation examines whether human experience, which individuals are not able to consciously transpose into the symbolic representation, can still be captured using the techniques of affective computing.First, a theoretical framework for description of human experience which is not accessible for conscious awareness was formulated. This framework was based on the work of Carl Jung who introduced a model of a psyche that includes three levels: consciousness, the personal unconscious and the collective unconscious. Consciousness is the external layer of the psyche that consists of those thoughts and emotions which are available for one¿s conscious recollection. The personal unconscious represents a repository for all of an individual¿s feelings, memories, knowledge and thoughts that are not conscious at a given moment of time.The collective unconscious is a repository of universal modes and behaviors that are similar in all individuals. According to Jung, the collective unconscious is populated with archetypes. Archetypes are prototypical categories of objects, people and situations that existed across evolutionary time and in different cultures.Esta tesis doctoral examina si la experiencia humana, que los individuos no pueden transponer conscientemente a la representación simbólica, aún puede capturarse utilizando las técnicas de computación afectiva. Primero, se formula un marco teórico para la descripción de la experiencia humana que no es accesible para la conciencia consciente. Este marco se basó en el trabajo de Carl Jung, quien introdujo un modelo de psique que incluye tres niveles: la conciencia, el inconsciente personal y el inconsciente colectivo. Habiendo definido nuestro marco teórico, realizamos un experimento en el que se mostraron a los sujetos estímulos visuales y auditivos de bases de datos estandarizadas para la obtención de emociones conscientes. Aparte de los estímulos para las emociones conscientes, los sujetos fueron expuestos a estímulos que representaban el arquetipo del yo. Durante la presentación de los estímulos cardiovasculares se registraron las señales de los sujetos. Los resultados experimentales indicaron que las respuestas de la frecuencia cardíaca de los participantes fueron únicas para cada categoría de estímulos, incluido el arquetípico. Estos hallazgos dieron impulso a realizar otro estudio en el que se examinó un espectro más amplio de experiencias arquetípicas. En nuestro segundo estudio, hicimos un cambio de estímulos visuales y auditivos a estímulos audiovisuales porque se esperaba que los videos fueran más eficientes en la obtención de emociones conscientes y experiencias arquetípicas que las imágenes fijas o los sonidos. La cantidad de arquetipos aumentó y los sujetos en general fueron estimulados a sentir ocho experiencias arquetípicas diferentes. También preparamos estímulos para emociones conscientes. En este experimento, las señales fisiológicas incluyeron actividades cardiovasculares, electrodérmicas, respiratorias y temperatura de la piel. El análisis estadístico sugirió que las experiencias arquetípicas podrían diferenciarse en función de las activaciones fisiológicas. Además, se construyeron varios modelos de predicción basados en los datos fisiológicos recopilados. Estos modelos demostraron la capacidad de clasificar los arquetipos con una precisión que era considerablemente más alta que el nivel de probabilidad. Como los resultados del segundo estudio sugirieron una relación positiva entre las experiencias arquetípicas y las activaciones de señales fisiológicas, parecía razonable realizar otro estudio para confirmar la generalización de nuestros hallazgos. Sin embargo, antes de comenzar un nuevo experimento, se decidió construir una herramienta que pudiera facilitar la recopilación de datos fisiológicos y el reconocimiento de experiencias arquetípicas, así como de emociones conscientes. Tal herramienta nos ayudaría a nosotros y a otros investigadores a realizar experimentos sobre la experiencia humana. Nuestra herramienta funciona en "tablets" y admite la recopilación y el análisis de datos de sensores fisiológicos. El último estudio se realizó utilizando una metodología similar al segundo experimento con varias modificaciones que tenían como objetivo obtener resultados más sólidos. El esfuerzo de realizar este estudio se redujo considerablemente al usar la herramienta desarrollada. Durante el experimento, sólo medimos las actividades cardiovasculares y electrodérmicas de los sujetos porque nuestros experimentos anteriores mostraron que estas dos señales contribuyeron significativamente a la clasificación de las emociones conscientes y las experiencias arquetípicas. El análisis estadístico indicó una relación significativa entre los arquetipos retratados en los videos y las respuestas fisiológicas de los sujetos. Además, utilizando métodos de minería de datos, creamos modelos de predicción que fueron capaces de reconocer las experiencias arquetípicas con una precisión menor que en el segundo estudio, pero todavía considerablemente..

Digitizing arquetypal human expereience through physiological signals

The problem of capturing human experience is relevant in many application domains. In fact, the process of describing and sharing individual experience lies at the heart of human culture. This advancement came at a price of losing some of the multidimensional aspects of primary, bodily experience during its projection into the symbolic formThroughout the courses of our lives we learn a great deal of information about the world from other people's experience. Besides the ability to share utilitarian experience such as whether a particular plant is poisonous, humans have developed a sophisticated competency of social signaling that enables us to express and decode emotional experience. The natural way of sharing emotional experiences requires those who share to be co-present during this event. However, people have overcome the limitation of physical presence by creating a symbolic system of representations.Recent research in the field of affective computing has addressed the question of digitization and transmission of emotional experience through monitoring and interpretation of physiological signals. Although the outcomes of this research represent a great step forward in developing a technology that supports sharing of emotional experiences, they do not seem to help in preserving the original phenomenological experience during the aforementioned projection. This circumstance is explained by the fact that in affective computing the focus of investigation has been aimed at emotional experiences which can be consciously evaluated and described by individuals themselves. Therefore, generally speaking, applying an affective computing technique for capturing emotions of an individual is not a deeper or more precise way to project her experience into the symbolic form than asking this person to write down a description of her emotions on a piece of paper. One can say that so far the research in affective computing has aimed at delivering technology that could automate the projection but it has not considered the problem of improving the projection in order to preserve more of the multidimensional aspects of human experience.This dissertation examines whether human experience, which individuals are not able to consciously transpose into the symbolic representation, can still be captured using the techniques of affective computing.First, a theoretical framework for description of human experience which is not accessible for conscious awareness was formulated. This framework was based on the work of Carl Jung who introduced a model of a psyche that includes three levels: consciousness, the personal unconscious and the collective unconscious. Consciousness is the external layer of the psyche that consists of those thoughts and emotions which are available for one¿s conscious recollection. The personal unconscious represents a repository for all of an individual¿s feelings, memories, knowledge and thoughts that are not conscious at a given moment of time.The collective unconscious is a repository of universal modes and behaviors that are similar in all individuals. According to Jung, the collective unconscious is populated with archetypes. Archetypes are prototypical categories of objects, people and situations that existed across evolutionary time and in different cultures.Esta tesis doctoral examina si la experiencia humana, que los individuos no pueden transponer conscientemente a la representación simbólica, aún puede capturarse utilizando las técnicas de computación afectiva. Primero, se formula un marco teórico para la descripción de la experiencia humana que no es accesible para la conciencia consciente. Este marco se basó en el trabajo de Carl Jung, quien introdujo un modelo de psique que incluye tres niveles: la conciencia, el inconsciente personal y el inconsciente colectivo. Habiendo definido nuestro marco teórico, realizamos un experimento en el que se mostraron a los sujetos estímulos visuales y auditivos de bases de datos estandarizadas para la obtención de emociones conscientes. Aparte de los estímulos para las emociones conscientes, los sujetos fueron expuestos a estímulos que representaban el arquetipo del yo. Durante la presentación de los estímulos cardiovasculares se registraron las señales de los sujetos. Los resultados experimentales indicaron que las respuestas de la frecuencia cardíaca de los participantes fueron únicas para cada categoría de estímulos, incluido el arquetípico. Estos hallazgos dieron impulso a realizar otro estudio en el que se examinó un espectro más amplio de experiencias arquetípicas. En nuestro segundo estudio, hicimos un cambio de estímulos visuales y auditivos a estímulos audiovisuales porque se esperaba que los videos fueran más eficientes en la obtención de emociones conscientes y experiencias arquetípicas que las imágenes fijas o los sonidos. La cantidad de arquetipos aumentó y los sujetos en general fueron estimulados a sentir ocho experiencias arquetípicas diferentes. También preparamos estímulos para emociones conscientes. En este experimento, las señales fisiológicas incluyeron actividades cardiovasculares, electrodérmicas, respiratorias y temperatura de la piel. El análisis estadístico sugirió que las experiencias arquetípicas podrían diferenciarse en función de las activaciones fisiológicas. Además, se construyeron varios modelos de predicción basados en los datos fisiológicos recopilados. Estos modelos demostraron la capacidad de clasificar los arquetipos con una precisión que era considerablemente más alta que el nivel de probabilidad. Como los resultados del segundo estudio sugirieron una relación positiva entre las experiencias arquetípicas y las activaciones de señales fisiológicas, parecía razonable realizar otro estudio para confirmar la generalización de nuestros hallazgos. Sin embargo, antes de comenzar un nuevo experimento, se decidió construir una herramienta que pudiera facilitar la recopilación de datos fisiológicos y el reconocimiento de experiencias arquetípicas, así como de emociones conscientes. Tal herramienta nos ayudaría a nosotros y a otros investigadores a realizar experimentos sobre la experiencia humana. Nuestra herramienta funciona en "tablets" y admite la recopilación y el análisis de datos de sensores fisiológicos. El último estudio se realizó utilizando una metodología similar al segundo experimento con varias modificaciones que tenían como objetivo obtener resultados más sólidos. El esfuerzo de realizar este estudio se redujo considerablemente al usar la herramienta desarrollada. Durante el experimento, sólo medimos las actividades cardiovasculares y electrodérmicas de los sujetos porque nuestros experimentos anteriores mostraron que estas dos señales contribuyeron significativamente a la clasificación de las emociones conscientes y las experiencias arquetípicas. El análisis estadístico indicó una relación significativa entre los arquetipos retratados en los videos y las respuestas fisiológicas de los sujetos. Además, utilizando métodos de minería de datos, creamos modelos de predicción que fueron capaces de reconocer las experiencias arquetípicas con una precisión menor que en el segundo estudio, pero todavía considerablemente..

Técnicas de minería de datos en el proceso de secuencias temporales. Aplicaciones a la clasificación industrial de sonidos

El proceso de secuencias temporales supone un campo de trabajo específico dentro de las técnicas de minería de datos o aprendizaje automático. Entre las tareas de esta disciplina se encuentra la clasificación de secuencias temporales que, por su especificidad, admite el uso de tratamientos diferenciados. Entre los datos con estructura de secuencia temporal pueden destacarse las señales sonoras. Existen numerosas aplicaciones en las que resulta de utilidad la clasificación automatizada de sonidos. En muchas de ellas se requiere que la solución propuesta tenga unas características que podríamos calificar de industriales: robustez, inmunidad al ruido, normalización, operación en tiempo real, bajo consumo y bajo coste. En esta tesis se analizan y comparan distintos métodos de clasificación de sonidos. Para ello, se segmentan los sonidos en fragmentos (ventanas) de muy corta duración y se propone el uso del estándar ISO MPEG-7, cuya aplicación permite obtener un conjunto normalizado de parámetros. Se consideran hasta nueve algoritmos de clasificación que, tomando como patrones distintos sonidos de clases conocidas, realizan una clasificación supervisada sin tener en cuenta el carácter secuencial de las mismas (clasificación no secuencial). Para tener en cuenta el carácter secuencial de los sonidos se proponen y comparan distintos métodos (clasificación secuencial). Para pasar de la clasificación de una ventana, o secuencia de ventanas, a la clasificación de un sonido completo la presente investigación propone una clasificación de series derivadas. Se define una serie (vectorial) derivada como la secuencia de probabilidades de que cada ventana pertenezca a una determinada clase. Se propone la caracterización de las series derivadas como si se tratase de sonidos, es decir, mediante la caracterización de cada uno de sus ventanas usando parámetros MPEG-7 y su posterior clasificación supervisada usando alguno de los algoritmos clasificadores propios de la minería de datos. El resultado del análisis realizado permite afirmar que el uso de los parámetros MPEG-7 constituye una buena alternativa para caracterizar sonidos. En la aplicación analizada el mejor clasificador no secuencial ha resultado ser el árbol de decisión. Por otra parte, la introducción de un método de ventana deslizante aparece como la mejor opción de clasificación secuencial, aunque con una mejora muy discreta sobre la técnica no secuencial. Adicionalmente, se ha podido evidenciar que la clasificación de las series derivadas supone una mejora muy notable en las prestaciones del clasificador. Por último, se ha comprobado que la solución propuesta presenta las características adecuadas para poder proclamar su carácter industrial

Modelagem simbólica de padrões morfológicos para classificação de séries temporais

Orientador : Prof. Dr. Fabiano SilvaTese (Doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 14/09/2015Inclui referências : f. 149-167Resumo: O contínuo armazenamento de dados ao longo do tempo, tais como séries temporais, tem motivado o desenvolvimento de novas abordagens baseadas em métodos de mineração de dados. Nesse cenário, uma nova área de pesquisa emergiu durante as últimas duas décadas, a mineração de dados em séries temporais. Mais especificamente, as abordagens baseadas em técnicas de aprendizado de máquina têm apresentado maior interesse entre os pesquisadores. Dentre as tarefas de mineração de dados, a classificação de séries temporais tem sido amplamente explorada, de modo que estudos recentes, utilizando algoritmos de aprendizado não simbólicos, têm reportado resultados significativos, em termos da acurácia de classificação. No entanto, em aplicações que envolvem processos de auxílio à tomada de decisão, tais como diagnóstico médico, controle de produção industrial, sistemas de monitoração de segurança em aeronaves ou usinas de energia elétrica, é necessário possibilitar o entendimento do raciocínio utilizado no processo de classificação. A primitiva shapelet foi proposta na literatura como um descritor de características morfológicas locais para possibilitar melhor compreensão dos conceitos, devido a sua maior proximidade com a percepção humana na identificação de padrões em séries temporais. Contudo, a maioria dos trabalhos relacionados ao estudo dessa primitiva tem se dedicado ao desenvolvimento de abordagens mais eficientes em termos de tempo e de acurácia, desconsiderando a necessidade da inteligibilidade dos classificadores. Nesse contexto, neste trabalho foi proposto um método que utiliza a transformada shapelet para a construção de modelos simbólicos de classificação por meio de uma abordagem híbrida que combina a representação de árvore de decisão com o algoritmo vizinho mais próximo. Também, foram desenvolvidas estratégias para melhorar a qualidade de representação da transformada shapelet na utilização de classificadores simbólicos, como árvores de decisão. Para avaliar o desempenho dessas propostas, foi conduzida uma avaliação experimental que envolveu a comparação com os algoritmos considerados estado da arte usando conjuntos de dados amplamente estudados na literatura de classificação de séries temporais. Com base nos resultados e análises realizadas nesta tese, foi possível verificar que a melhoria do processo de identificação de shapelets possibilita a construção de classificadores inteligíveis e competitivos; e que métodos híbridos podem contribuir para prover uma representação simbólica dos modelos, com desempenho equivalente ou até mesmo superior aos métodos não simbólicos. Palavras-chave: mineração de dados. aprendizado de máquina. séries temporais. classificação. modelos simbólicos.Abstract: The large amount of stored data over time, such as time series, has motivated the development of new approaches based on data mining methods. In this context, a new research area has emerged over the last two decades, the time series data mining. In particular, the approaches based on machine learning techniques have shown large interest among researchers. Among the data mining tasks, the time series classification has been widely exploited. Recent studies using non-symbolic learning algorithms have reported significant results in terms of classification accuracy. However, in applications related to decision making process, such as medical diagnosis, industrial production control, security monitoring systems in aircraft and in power plants, it is necessary allow the understanding of the reasoning used in the classification process. To take this into account, the shapelet primitive has been proposed in the literature as a descriptor of local morphological characteristics, which is closer to human perception for patterns identification in time series. On the other hand, most of the existing work related to shapelets has been dedicated to the development of more effective approaches in terms of time and accuracy, disregarding the need for interpretability of the classifiers. In this work, we propose to build symbolic models for time series classification using the shapelet transformation. This method is based on a hybrid approach that merges the decision tree representation and the nearest neighbor algorithm. Also, we developed strategies to improve the representation quality of the shapelet transformation using feature selection algorithms. We performed an experimental evaluation to analyze the performance of our proposals in comparison to the algorithms considered state of the art using datasets widely studied in the literature of time series classification. Based on the results and analysis carried out in this thesis, we found that the improvement of shapelet representation allows the construction of interpretable and competitive classifiers. Moreover, we found that the hybrid methods can help to provide symbolic models with equivalent or even superior performance to non-symbolic methods. Keywords: data mining. machine learning. time series. classification. symbolic models

Large dataset complexity reduction for classification: An optimization perspective

Doctor of PhilosophyComputational complexity in data mining is attributed to algorithms but lies hugely with the data. Different algorithms may exist to solve the same problem, but the simplest is not always the best. At the same time, data of astronomical proportions is rather common, boosted by automation, and the fuller the data, the better resolution of the concept it projects. Paradoxically, it is the computing power that is lacking. Perhaps a fast algorithm can be run on the data, but not the optimal. Even then any modeling is much constrained, involving serial application of many algorithms. The only other way to relieve the computational load is via making the data lighter. Any representative subset has to preserve the data essence suiting, ideally, any algorithm. The reduction should minimize the error of approximation, while trading precision for performance. Data mining is a wide field. We concentrate on classification. In the literature review we present a variety of methods, emphasizing the effort of past decade. Two major objects of reduction are instances and attributes. The data can be also recast into a more economical format. We address sampling, noise reduction, class domain binarization, feature ranking, feature subset selection, feature extraction, and also discretization of continuous features. Achievements are tremendous, but so are possibilities. We improve an existing technique of data cleansing and suggest a way of data condensing as the extension. We also touch on noise reduction. Instance similarity, excepting the class mix, prompts a technique of feature selection. Additionally, we consider multivariate discretization, enabling a compact data representation without the size change. We compare proposed methods with alternative techniques which we introduce new, implement or use available