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Development of a Complete Minuscule Microscope: Embedding Data Pipeline and Machine Learning Segmentation / Utveckling av ett Fullständigt Miniatyr-Mikroskop: Integrering av Dataflöde och MaskininlärningssegmenteringZec, Kenan January 2023 (has links)
Cell culture is a fundamental procedure in many laboratories and precedes much research performed under the microscope. Despite the significance of this procedural stage, the monitoring of cells throughout growth is impossible due to the absence of equipment and methodological approaches. This thesis presents a low-cost, power-effective and versatile microscope with small enough dimensions to operate inside an incubator. Besides image acquisition, the microscope comprises other functions such as a data pipeline, implemented to save the images on the user’s computer via a server whilst also offering storage of the images on an integrated micro SD-card. Furthermore, a machine learning algorithm with a human-in-the-loop approach has been trained to segment the acquired images for cell proliferation and cell apoptosis tracking, and yielded promising results with an accuracy of 94%. For comparison, conventional segmentation techniques using operations such as the watershed function were deployed.The microscope described is versatile in operation as it offers the user to utilise one or more functions, depending on the purpose of the imaging. / Cellodling är en grundläggande process i många laboratiorium och föregår forskning som utförs under mikroskop. Trots inkubationens betydelse har övervakning av celler i detta skede inte varit möjlig på grund utav avsaknaden av relevant utrustning och metodologiska tillvägagångsätt. I denna examensuppsatts på avancerad nivå presenteras ett lågkostnads-, energieffektivt och versatilt mikroskop av centimeterstora dimensioner anpassat för användning i en inkubator. Förutom bildtagningsmekanismer erbjuder mikroskopet olika funktioner som till exempel ett integrerat dataflöde som möjliggör sparande av bilder på användarens dator via en server samtidigt som den erbjuder sparande av bilder på ett integrerat minneskort.Utöver detta har en human-in-the-loop maskininlärningsalgoritm för segmentation av celler implementerats i syfte att övervaka cellernas celldelning och celldöd. Denna algoritm påvisade goda resultat med en nogrannhet på 94%. I jämförelsesyfte har även en traditionell watershed-baserad cellsegmenteringsteknik utvecklats.Mikroskopet kan kallas versatilt då det tillåter användaren att anpassa dataflödet och välja vilka funktioner denne vill nyttja, allt utefter bildtagningens ändamål.
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Toward the "Deep Learning" of Brain White Matter StructuresAstolfi, Pietro 08 April 2022 (has links)
In the brain, neuronal cells located in different functional regions communicate through a dense structural network of axons known as the white matter (WM) tissue. Bundles of axons that share similar pathways characterize the WM anatomy, which can be investigated in-vivo thanks to the recent advances of magnetic resonance (MR) techniques. Diffusion MR imaging combined with tractography pipelines allows for a virtual reconstruction of the whole WM anatomy of in-vivo brains, namely the tractogram. It consists of millions of WM fibers as 3D polylines, each approximating thousands of axons. From the analysis of a tractogram, neuroanatomists can characterize well-known white matter structures and detect anatomically non-plausible fibers, which are artifacts of the tractography and often constitute a large portion of it. The accurate characterization of tractograms is pivotal for several clinical and neuroscientific applications. However, such characterization is a complex and time-consuming process that is difficult to be automatized as it requires properly encoding well-known anatomical priors. In this thesis, we propose to investigate the encoding of anatomical priors with a supervised deep learning framework. The ultimate goal is to reduce the presence of artifactual fibers to enable a more accurate automatic process of WM characterization. We devise the problem by distinguishing between volumetric and non-volumetric representations of white matter structures. In the first case, we learn the segmentation of the WM regions that represent relevant anatomical waypoints not yet classified by WM atlases. We investigate using Convolutional Neural Networks (CNNs) to exploit the volumetric representation of such priors. In the second case, the goal is to learn from the 3D polyline representation of fibers where the typical CNN models are not suitable. We introduce the novelty of using Geometric Deep Learning (GDL) models designed to process data having an irregular representation. The working assumption is that the geometrical properties of fibers are informative for the detection of tractogram artifacts. As a first contribution, we present StemSeg that extends the use of CNNs to detect the WM portion representing the waypoints of all the fibers for a specific bundle. This anatomical landmark, called stem, can be critical for extracting that bundle. We provide the results of an empirical analysis focused on the Inferior Fronto-Occipital Fasciculus (IFOF). The effective segmentation of the stem improves the final segmentation of the IFOF, outperforming with a significant gap the reference state of the art. As a second and major contribution, we present Verifyber, a supervised tractogram filtering approach based on GDL, distinguishing between anatomically plausible and non-plausible fibers. The proposed model is designed to learn anatomical features directly from the fiber represented as a 3D points sequence. The extended empirical analysis on healthy and clinical subjects reveals multiple benefits of Verifyber: high filtering accuracy, low inference time, flexibility to different plausibility definitions, and good generalization. Overall, this thesis constitutes a step toward characterizing white matter using deep learning. It provides effective ways of encoding anatomical priors and an original deep learning model designed for fiber.
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Detection and categorization of suggestive thumbnails : A step towards a safer internet / Upptäckt och kategorisering av suggestiva miniatyrer : Ett steg mot ett säkrare internetOliveira Franca, Matheus January 2021 (has links)
The aim of this work is to compare methods that predict whether an image has suggestive content, such as pornographic images and erotic fashion. Using binary classification, this work contributes to an internet environment where these images are not seen out of context. It is, therefore, necessary for user experience improvement purposes, such as child protection, publishers not having their campaign associated with inappropriate content, and companies improving their brand safety. For this study, a data set with more than 500k images was created to test the Convolutional Neural Networks (CNN) models: NSFW model, ResNet, EfficientNet, BiT, NudeNet and Yahoo Model. The image classification model EfficientNet-B7 and Big Transfer (BiT) presented the best results with over 91% samples correctly classified on the test set, with precision and recall around 0.7. Model prediction was further investigated using Local Interpretable Model-agnostic Explanation (LIME), a model explainability technique, and concluded that the model uses coherent regions of the thumbnail according to a human perspective such as legs, abdominal, and chest to classify images as unsafe. / Syftet med detta arbete är att jämföra metoder som förutsäger om en bild har suggestivt innehåll, såsom pornografiska bilder och erotiskt mode. Med binär klassificering bidrar detta arbete till en internetmiljö där dessa bilder inte ses ur sitt sammanhang. Det är därför nödvändigt för att förbättra användarupplevelsen, till exempel barnskydd, utgivare som inte har sina kampanjer kopplade till olämpligt innehåll och företag som förbättrar deras varumärkessäkerhet. För denna studie skapades en datamängd med mer än 500 000 bilder för att testa Convolutional Neural Networks (CNN) modeller: NSFW-modell, ResNet, EfficientNet, BiT, NudeNet och Yahoo-modell. Bild klassificerings modellen EfficientNet-B7 och Big Transfer (BiT) presenterade de bästa resultaten med över 91%prover korrekt klassificerade på testuppsättningen, med precision och återkallelse runt 0,7. Modell förutsägelse undersöktes ytterligare med hjälp av Local Interpretable Model-agnostic Explanation (LIME), en modell förklarbarhetsteknik, och drog slutsatsen att modellen använder sammanhängande regioner i miniatyren enligt ett mänskligt perspektiv såsom ben, buk och bröst för att klassificera bilder som osäkra.
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Adversarial Attacks On Graph Convolutional Transformer With EHR DataSiddhartha Pothukuchi (18437181) 28 April 2024 (has links)
<p dir="ltr">This research explores adversarial attacks on Graph Convolutional Transformer (GCT) models that utilize Electronic Health Record (EHR) data. As deep learning models become increasingly integral to healthcare, securing their robustness against adversarial threats is critical. This research assesses the susceptibility of GCT models to specific adversarial attacks, namely the Fast Gradient Sign Method (FGSM) and the Jacobian-based Saliency Map Attack (JSMA). It examines their effect on the model’s prediction of mortality and readmission. Through experiments conducted with the MIMIC-III and eICU datasets, the study finds that although the GCT model exhibits superior performance in processing EHR data under normal conditions, its accuracy drops when subjected to adversarial conditions—from an accuracy of 86% with test data to about 57% and an area under the curve (AUC) from 0.86 to 0.51. These findings averaged across both datasets and attack methods, underscore the urgent need for effective adversarial defense mechanisms in AI systems used in healthcare. This thesis contributes to the field by identifying vulnerabilities and suggesting various strategies to enhance the resilience of GCT models against adversarial manipulations.</p>
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Deep Multimodal Physiological Learning Of Cerebral Vasoregulation Dynamics On Stroke Patients Towards Precision Brain MedicineAkanksha Tipparti (18824731) 03 September 2024 (has links)
<p dir="ltr">Impaired cerebral vasoregulation is one of the most common post-ischemic stroke effects. Diagnosis and prevention of this condition is often invasive, costly and in-effective. This impairment restricts the cerebral blood vessels to properly regulate blood flow, which is very important for normal brain functioning. Developing accurate, non-invasive and efficient methods to detect this condition aids in better stroke diagnosis and prevention. </p><p dir="ltr">The aim of this thesis is to develop deep learning techniques for the purpose of detection of cerebral vasoregulation impairments by analyzing physiological signals. This research employs various Deep learning techniques like Convolution Neural Networks (CNN), MobileNet, and Long-Short-Term Memory (LSTM) to determine variety of physiological signals from the PhysioNet database like Electrocardio-gram (ECG), Transcranial Doppler (TCD), Electromyogram (EMG), and Blood Pressure(BP) as stroke or non-stroke subjects. The effectiveness of these algorithms is demonstrated by a classification accuracy of 90\% for the combination of ECG and EMG signals. </p><p dir="ltr">Furthermore, this research explores the importance of analyzing dynamic physiological activities in determining the impairment. The dynamic activities include Sit-stand, Sit-stand-balance, Head-up-tilt, and Walk dataset from the PhysioNet website. CNN and MobileNetV3 are employed in classification purposes of these signals, attempting to identify cerebral health. The accuracy of the model and robustness of these methods is greatly enhanced when multiple signals are integrated. </p><p dir="ltr">Overall, this study highlights the potential of deep multimodal physiological learning in the development of precision brain medicine further enhancing stroke diagnosis. The results pave the way for the development of advanced diagnostic tools to determine cerebral health. </p>
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Deep Learning Based High-Resolution Statistical Downscaling to Support Climate Impact Modelling: The Case of Species Distribution ProjectionsQuesada Chacón, Dánnell 16 May 2024 (has links)
Urgent scientifically-informed action is needed to stabilise the Earth System amidst anthropogenic climate change. Particularly, the notable transgression of the ‘biosphere integrity’ Planetary Boundary needs to be addressed. Modern Earth System Models struggle to accurately represent regional to local-scale climate features and biodiversity aspects. Recent developments allow to tackle these issues using Artificial Intelligence.
This dissertation focuses on two main aspects: (i) deriving high spatio-temporal resolution climate data from coarser models; and (ii) integrating high-temporal-resolution climate data into Species Distribution Models. Three specific objectives were defined:
Obj1 Improving Perfect Prognosis – Statistical Downscaling methods through modern Deep Learning algorithms.
Obj2 Downscaling a high-resolution multivariate climate ensemble.
Obj3 Employ the resulting dataset to improve Species Distribution Models’ projections.
The objectives are connected to the three articles that support this cumulative dissertation. Its scope is limited to the Free State of Saxony, Germany, where local high-resolution climate data and high-quality observations of endangered vascular plant species were employed. From a broader perspective, these efforts should contribute to the overarching goal of bridging the gap between the scales of species distribution and climate models while establishing open-source, reproducible, and scalable containerised frameworks.
Recent Deep Learning algorithms were leveraged to accomplish (i). The proposed frameworks enhance previous performance of Perfect Prognosis – Statistical Downscaling approaches, while ensuring repeatability. The key near-surface variables considered are precipitation, water vapour pressure, radiation, wind speed, and, maximum, mean and minimum temperature. The assumptions that support the Perfect Prognosis approach were thoroughly examined, confirming the robustness of the methods. The downscaled ensemble exhibits a novel output resolution of daily 1 km, which can serve as input for multiple climate impact studies, especially for local-scale decision-making and in topographically complex regions.
Considerable methodological implementations were proposed and thoroughly analysed to achieve (ii). Despite notable limitations, Species Distribution Models are frequently used in climate change conservation planning. Thus, recent developments in climate data resolution could improve their usefulness and reliability, which have been previously constraint to coarse temporal aggregates in the projection domain. The presented framework provides fine-grained species suitability projections and satisfactory spatio-temporal transferability, albeit worrying trends. These improved projections are a step forward towards tailored conservation efforts.
Limitations of Machine Learning methods and Species Distribution Models are addressed. Substantial avenues for future improvements are thoroughly discussed. As results suggest further reduction of suitable habitats, yet another call for swift action towards low-carbon societies is made. This requires maximising climate change mitigation and adaptation measures, along with a swift transition from short-term profit-driven policies to long-term sustainable development, but primarily, a collective shift in consciousness from anthropocentric positions to ecocentric policies and societies.:Contents
Declaration of conformity........................................................ I
Abstract....................................................................... III
Zusammenfassung.................................................................. V
Resumen........................................................................ VII
Acknowledgments................................................................. IX
List of Figures................................................................. XV
List of Tables................................................................. XIX
Symbols and Acronyms........................................................... XXI
I Prelude & Foundations 1
1 Introduction................................................................... 3
1.1 Motivation – Human Impact on Earth....................................... 3
1.2 Earth System Modelling and Downscaling................................... 5
1.3 Biosphere’s Response to Recent Changes................................... 8
1.4 Species Distribution Models.............................................. 9
1.5 Objectives.............................................................. 10
1.6 Scope................................................................... 10
1.7 Outline................................................................. 10
2 Methodological Basis.......................................................... 13
2.1 Introduction to Artificial Intelligence Methods......................... 13
2.1.1 Artificial Intelligence........................................... 13
2.1.2 Machine Learning.................................................. 14
2.1.3 Deep Learning..................................................... 14
2.2 Downscaling Techniques.................................................. 15
2.2.1 Dynamical Downscaling............................................. 15
2.2.2 Statistical Downscaling........................................... 15
2.2.2.1 Model Output Statistics................................... 16
2.2.2.2 Perfect Prognosis......................................... 16
2.3 Species Distribution Models: Temporal Aspects........................... 17
2.4 Computational Framework................................................. 18
2.4.1 High-Performance Computing........................................ 18
2.4.2 Containers........................................................ 18
2.5 Remarks on Reproducibility.............................................. 19
II Articles’ Synthesis 21
3 Data.......................................................................... 23
3.1 Study Area.............................................................. 23
3.2 ReKIS................................................................... 24
3.3 ERA5.................................................................... 24
3.4 CORDEX.................................................................. 24
3.5 Species Occurrences..................................................... 25
3.6 WorldClim............................................................... 26
4 Methodological Implementations................................................ 27
4.1 Advancing Statistical Downscaling....................................... 27
4.1.1 Transfer Function Calibration.................................... 27
4.1.2 Evaluation....................................................... 29
4.1.3 Repeatability.................................................... 29
4.2 Downscaling a Multivariate Ensemble..................................... 30
4.2.1 Transfer Function Adaptations.................................... 30
4.2.2 Validation....................................................... 30
4.2.3 Perfect Prognosis Assumptions Evaluation......................... 31
4.3 Integrating High-Temporal-Resolution into SDMs.......................... 32
4.3.1 Climate Data..................................................... 32
4.3.1.1 Predictor Sets.......................................... 32
4.3.1.2 Temporal Approaches..................................... 33
4.3.2 SDM Implementation............................................... 33
4.3.3 Spatio-Temporal Thinning & Trimming.............................. 33
4.3.4 Meta-analysis.................................................... 34
4.3.5 Pseudo-Reality Assessment........................................ 34
4.3.6 Spatio-Temporal Transferability.................................. 34
5 Results & Discussions......................................................... 35
5.1 Advancing Statistical Downscaling....................................... 35
5.1.1 Performance Improvement.......................................... 35
5.1.2 Repeatability.................................................... 36
5.1.3 Transfer Function Suitability.................................... 38
5.2 Downscaling a Multivariate Ensemble..................................... 39
5.2.1 Transfer Function performance.................................... 39
5.2.2 Bias-Correction.................................................. 40
5.2.3 Pseudo-Reality................................................... 42
5.2.4 Projections...................................................... 43
5.3 Integrating High-Temporal-Resolution into SDMs.......................... 45
5.3.1 Predictor Set Evaluation for H2k................................. 45
5.3.2 Temporal Approach Comparison..................................... 46
5.3.3 Spatio-Temporal Transferability.................................. 47
5.3.4 Suitability Projections.......................................... 47
III Insights 51
6 Summary....................................................................... 53
6.1 Article A1.............................................................. 53
6.2 Article A2.............................................................. 54
6.3 Article A3.............................................................. 56
7 Conclusions and Outlook....................................................... 59
References 65
Articles 81
A1 Repeatable high-resolution statistical downscaling through deep learning..... 83
A2 Downscaling CORDEX Through Deep Learning to Daily 1 km Multivariate Ensemble
in Complex Terrain............................................................. 103
A3 Integrating High-Temporal-Resolution Climate Projections into Species Distribu-
tion Model..................................................................... 127 / Um das Erdsystem angesichts des anthropogenen Klimawandels zu stabilisieren, sind Maßnahmen auf Basis wissenschaftlicher Erkenntnisse dringend erforderlich. Insbesondere muss die drastisch Überschreitung der planetaren Grenze ‘Integrität der Biosphäre’ angegangen werden. Bisher haben aber Modelle des Erdsystems Schwierigkeiten, regionale bis lokale Klimamerkmale und Aspekte der Biodiversität genau abzubilden. Aktuelle Entwicklungen ermöglichen es, diese Herausforderungen mithilfe von Künstlicher Intelligenz anzugehen.
Diese Dissertation konzentriert sich auf zwei Hauptaspekte: (i) die Ableitung von Klimadaten mit hoher räumlicher und zeitlicher Auflösung aus groberen Modellen und (ii) die Integration von Klimadaten mit hoher zeitlicher Auflösung in Modelle zur Artverbreitung. Es wurden drei konkrete Ziele definiert:
Ziel1 Verbesserung von Perfect Prognosis – Statistische Downscaling-Methoden durch moderne Deep Learning-Algorithmen
Ziel2 Downscaling eines hochauflösenden multivariaten Klimaensembles
Ziel3 Verwendung des resultierenden Datensatzes zur Verbesserung von Prognosen in Modellen zur Artverbreitung
Diese Ziele werden in drei wissenschaftlichen Artikeln beantwortet, auf die diese kumulative Dissertation sich stützt. Der Anwendungsbereich erstreckt sich auf den Freistaat Sachsen, Deutschland, wo lokale hochauflösende Klimadaten und hochwertige Beobachtungen gefährdeter Gefäßpflanzenarten verwendet wurden. In einer breiteren Perspektive tragen diese Bemühungen dazu bei, die Kluft zwischen regionalen sowie zeitlichen Skalen der Artverbreitung und Klimamodellen zu überbrücken und gleichzeitig Open-Source-, reproduzierbare und skalierbare containerisierte Frameworks zu etablieren.
Aktuelle Deep Learning-Algorithmen wurden eingesetzt, um Hauptaspekt (i) zu erreichen. Die vorgeschlagenen Frameworks verbessern die bisherige Leistung von Perfect Prognosis – Statistische Downscaling-Ansätzen und gewährleisten gleichzeitig die Wiederholbarkeit. Die wichtigsten bodennahen Variablen, die berücksichtigt werden, sind Niederschlag, Wasserdampfdruck, Strahlung, Windgeschwindigkeit sowie Maximal-, Durchschnitts- und Minimaltemperatur. Die Annahmen, die den Perfect Prognosis-Ansatz unterstützen, wurden analysiert und bestätigen die Robustheit der Methoden. Das downscaled Ensemble weist eine neuartige Auflösung von 1 km auf Tagesbasis auf, welches als Grundlage für mehrere Studien zu den Auswirkungen des Klimawandels dienen kann, insbesondere für Entscheidungsfindung auf lokaler Ebene und in topografisch komplexen Regionen.
Es wurden umfassende methodische Implementierungen vorgeschlagen und analysiert, um Hauptaspekt (ii) zu erreichen. Trotz großer Einschränkungen werden Modelle zur Artverbreitung häufig in der Klimaschutzplanung eingesetzt. Daher könnten aktuelle Entwicklungen in der Klimadatenauflösung deren Nützlichkeit und Zuverlässigkeit verbessern, die bisher auf grobe zeitliche Aggregatformen im Projektionsbereich beschränkt waren. Das vorgestellte Framework bietet feingliedrige Prognosen zur Eignung von Arten und zufriedenstellende räumlich-zeitliche Übertragbarkeit, trotz besorgniserregender Trends. Diese verbesserten Prognosen sind ein Schritt in Richtung maßgeschneiderter Naturschutzmaßnahmen.
Einschränkungen von Machine Learning-Methoden und Modellen zur Artverbreitung werden untersucht. Substanzielle Möglichkeiten zur zukünftigen Verbesserung werden ausführlich erörtert. Da die Ergebnisse darauf hinweisen, dass geeignete Lebensräume weiter abnehmen, wird erneut zum schnellen Handeln in Richtung kohlenstoffarmer Gesellschaften aufgerufen. Dies erfordert die Maximierung von Maßnahmen zur Bekämpfung des Klimawandels und zur Anpassung, zusammen mit einem raschen Übergang von kurzfristig Profitorientierten Politiken zu langfristiger nachhaltiger Entwicklung, aber vor allem zu einem kollektiven Bewusstseinswandel von anthropozentrischen Positionen zu ökozentrischen Politiken und Gesellschaften.:Contents
Declaration of conformity........................................................ I
Abstract....................................................................... III
Zusammenfassung.................................................................. V
Resumen........................................................................ VII
Acknowledgments................................................................. IX
List of Figures................................................................. XV
List of Tables................................................................. XIX
Symbols and Acronyms........................................................... XXI
I Prelude & Foundations 1
1 Introduction................................................................... 3
1.1 Motivation – Human Impact on Earth....................................... 3
1.2 Earth System Modelling and Downscaling................................... 5
1.3 Biosphere’s Response to Recent Changes................................... 8
1.4 Species Distribution Models.............................................. 9
1.5 Objectives.............................................................. 10
1.6 Scope................................................................... 10
1.7 Outline................................................................. 10
2 Methodological Basis.......................................................... 13
2.1 Introduction to Artificial Intelligence Methods......................... 13
2.1.1 Artificial Intelligence........................................... 13
2.1.2 Machine Learning.................................................. 14
2.1.3 Deep Learning..................................................... 14
2.2 Downscaling Techniques.................................................. 15
2.2.1 Dynamical Downscaling............................................. 15
2.2.2 Statistical Downscaling........................................... 15
2.2.2.1 Model Output Statistics................................... 16
2.2.2.2 Perfect Prognosis......................................... 16
2.3 Species Distribution Models: Temporal Aspects........................... 17
2.4 Computational Framework................................................. 18
2.4.1 High-Performance Computing........................................ 18
2.4.2 Containers........................................................ 18
2.5 Remarks on Reproducibility.............................................. 19
II Articles’ Synthesis 21
3 Data.......................................................................... 23
3.1 Study Area.............................................................. 23
3.2 ReKIS................................................................... 24
3.3 ERA5.................................................................... 24
3.4 CORDEX.................................................................. 24
3.5 Species Occurrences..................................................... 25
3.6 WorldClim............................................................... 26
4 Methodological Implementations................................................ 27
4.1 Advancing Statistical Downscaling....................................... 27
4.1.1 Transfer Function Calibration.................................... 27
4.1.2 Evaluation....................................................... 29
4.1.3 Repeatability.................................................... 29
4.2 Downscaling a Multivariate Ensemble..................................... 30
4.2.1 Transfer Function Adaptations.................................... 30
4.2.2 Validation....................................................... 30
4.2.3 Perfect Prognosis Assumptions Evaluation......................... 31
4.3 Integrating High-Temporal-Resolution into SDMs.......................... 32
4.3.1 Climate Data..................................................... 32
4.3.1.1 Predictor Sets.......................................... 32
4.3.1.2 Temporal Approaches..................................... 33
4.3.2 SDM Implementation............................................... 33
4.3.3 Spatio-Temporal Thinning & Trimming.............................. 33
4.3.4 Meta-analysis.................................................... 34
4.3.5 Pseudo-Reality Assessment........................................ 34
4.3.6 Spatio-Temporal Transferability.................................. 34
5 Results & Discussions......................................................... 35
5.1 Advancing Statistical Downscaling....................................... 35
5.1.1 Performance Improvement.......................................... 35
5.1.2 Repeatability.................................................... 36
5.1.3 Transfer Function Suitability.................................... 38
5.2 Downscaling a Multivariate Ensemble..................................... 39
5.2.1 Transfer Function performance.................................... 39
5.2.2 Bias-Correction.................................................. 40
5.2.3 Pseudo-Reality................................................... 42
5.2.4 Projections...................................................... 43
5.3 Integrating High-Temporal-Resolution into SDMs.......................... 45
5.3.1 Predictor Set Evaluation for H2k................................. 45
5.3.2 Temporal Approach Comparison..................................... 46
5.3.3 Spatio-Temporal Transferability.................................. 47
5.3.4 Suitability Projections.......................................... 47
III Insights 51
6 Summary....................................................................... 53
6.1 Article A1.............................................................. 53
6.2 Article A2.............................................................. 54
6.3 Article A3.............................................................. 56
7 Conclusions and Outlook....................................................... 59
References 65
Articles 81
A1 Repeatable high-resolution statistical downscaling through deep learning..... 83
A2 Downscaling CORDEX Through Deep Learning to Daily 1 km Multivariate Ensemble
in Complex Terrain............................................................. 103
A3 Integrating High-Temporal-Resolution Climate Projections into Species Distribu-
tion Model..................................................................... 127 / Acción urgente científicamente informada es necesaria para estabilizar el sistema terrestre en medio del cambio climático antropogénico. En particular, la notable transgresión del límite planetario de ’integridad de la biosfera’ debe abordarse. Los modernos modelos del sistema terrestre tienen dificultades para representar con precisión las características climáticas a escala regional y local, así como los aspectos de la biodiversidad. Desarrollos recientes permiten abordar estos problemas mediante la inteligencia artificial.
Esta disertación se enfoca en dos aspectos principales: (i) derivar datos climáticos de alta resolución espacio-temporal a partir de modelos más gruesos; y (ii) integrar datos climáticos de alta resolución temporal en modelos de distribución de especies. Se definieron tres objetivos específicos:
Obj1 Mejorar los métodos de pronóstico perfecto – reducción de escala estadística mediante algoritmos modernos de aprendizaje profundo.
Obj2 Generar un conjunto climático multivariado de alta resolución.
Obj3 Emplear el conjunto de datos resultante para mejorar las proyecciones de los modelos de distribución de especies.
Los objetivos están vinculados a los tres artículos que respaldan esta disertación acumulativa. Su alcance se limita al Estado Libre de Sajonia, Alemania, donde se emplearon datos climáticos locales de alta resolución y observaciones de alta calidad de especies de plantas vasculares en peligro de extinción. Desde una perspectiva más amplia, estos esfuerzos deberían contribuir a la meta general de cerrar la brecha entre las escalas de la distribución de especies y los modelos climáticos, mientras que se establecen marcos de trabajo contenedorizados de código abierto, reproducibles y escalables.
Algoritmos recientes de aprendizaje profundo fueron aprovechados para lograr (i). Los marcos de trabajo propuestos mejoran el rendimiento previo de los métodos de pronóstico perfecto – reducción de escala estadística, al tiempo que garantizan la repetibilidad. Las variables clave de la superficie cercana consideradas son precipitación, presión de vapor de agua, radiación, velocidad del viento, así como la temperatura máxima, media y mínima. Se examinaron meticulosamente las suposiciones que respaldan el método de pronóstico perfecto, confirmando la robustez de las propuestas. El conjunto reducido de escala exhibe una novedosa resolución diaria de 1 km, el cual puede servir como insumo para múltiples estudios de impacto climático, especialmente para la toma de decisiones a nivel local y en regiones topográficamente complejas.
Se propusieron y analizaron minuciosamente considerables implementaciones metodológicas para lograr (ii). A pesar de sus notables limitaciones, los modelos de distribución de especies son utilizados con frecuencia en la planificación de la conservación debido al cambio climático. Por lo tanto, los desarrollos recientes en la resolución de datos climáticos podrían mejorar su utilidad y confiabilidad, ya que antes se limitaban a agregados temporales gruesos en el caso de las proyecciones. El marco de trabajo presentado proporciona proyecciones de idoneidad de especies detalladas y una transferibilidad espacio-temporal satisfactoria, aunque con tendencias preocupantes. Estas proyecciones mejoradas son un paso adelante en los esfuerzos de conservación a la medida.
Se abordan las limitaciones de los métodos de aprendizaje automático y de los modelos de distribución de especies. Se discuten a fondo posibilidades sustanciales para futuras mejoras. Dado que los resultados sugieren una mayor reducción de hábitats adecuados, se hace otro llamado a la acción rápida hacia sociedades bajas en carbono. Esto requiere maximizar las medidas de mitigación y adaptación al cambio climático, junto con una transición rápida de políticas orientadas a beneficios a corto plazo hacia un desarrollo sostenible a largo plazo, pero principalmente, un cambio colectivo de conciencia, desde posiciones antropocéntricas hacia políticas y sociedades ecocéntricas.:Contents
Declaration of conformity........................................................ I
Abstract....................................................................... III
Zusammenfassung.................................................................. V
Resumen........................................................................ VII
Acknowledgments................................................................. IX
List of Figures................................................................. XV
List of Tables................................................................. XIX
Symbols and Acronyms........................................................... XXI
I Prelude & Foundations 1
1 Introduction................................................................... 3
1.1 Motivation – Human Impact on Earth....................................... 3
1.2 Earth System Modelling and Downscaling................................... 5
1.3 Biosphere’s Response to Recent Changes................................... 8
1.4 Species Distribution Models.............................................. 9
1.5 Objectives.............................................................. 10
1.6 Scope................................................................... 10
1.7 Outline................................................................. 10
2 Methodological Basis.......................................................... 13
2.1 Introduction to Artificial Intelligence Methods......................... 13
2.1.1 Artificial Intelligence........................................... 13
2.1.2 Machine Learning.................................................. 14
2.1.3 Deep Learning..................................................... 14
2.2 Downscaling Techniques.................................................. 15
2.2.1 Dynamical Downscaling............................................. 15
2.2.2 Statistical Downscaling........................................... 15
2.2.2.1 Model Output Statistics................................... 16
2.2.2.2 Perfect Prognosis......................................... 16
2.3 Species Distribution Models: Temporal Aspects........................... 17
2.4 Computational Framework................................................. 18
2.4.1 High-Performance Computing........................................ 18
2.4.2 Containers........................................................ 18
2.5 Remarks on Reproducibility.............................................. 19
II Articles’ Synthesis 21
3 Data.......................................................................... 23
3.1 Study Area.............................................................. 23
3.2 ReKIS................................................................... 24
3.3 ERA5.................................................................... 24
3.4 CORDEX.................................................................. 24
3.5 Species Occurrences..................................................... 25
3.6 WorldClim............................................................... 26
4 Methodological Implementations................................................ 27
4.1 Advancing Statistical Downscaling....................................... 27
4.1.1 Transfer Function Calibration.................................... 27
4.1.2 Evaluation....................................................... 29
4.1.3 Repeatability.................................................... 29
4.2 Downscaling a Multivariate Ensemble..................................... 30
4.2.1 Transfer Function Adaptations.................................... 30
4.2.2 Validation....................................................... 30
4.2.3 Perfect Prognosis Assumptions Evaluation......................... 31
4.3 Integrating High-Temporal-Resolution into SDMs.......................... 32
4.3.1 Climate Data..................................................... 32
4.3.1.1 Predictor Sets.......................................... 32
4.3.1.2 Temporal Approaches..................................... 33
4.3.2 SDM Implementation............................................... 33
4.3.3 Spatio-Temporal Thinning & Trimming.............................. 33
4.3.4 Meta-analysis.................................................... 34
4.3.5 Pseudo-Reality Assessment........................................ 34
4.3.6 Spatio-Temporal Transferability.................................. 34
5 Results & Discussions......................................................... 35
5.1 Advancing Statistical Downscaling....................................... 35
5.1.1 Performance Improvement.......................................... 35
5.1.2 Repeatability.................................................... 36
5.1.3 Transfer Function Suitability.................................... 38
5.2 Downscaling a Multivariate Ensemble..................................... 39
5.2.1 Transfer Function performance.................................... 39
5.2.2 Bias-Correction.................................................. 40
5.2.3 Pseudo-Reality................................................... 42
5.2.4 Projections...................................................... 43
5.3 Integrating High-Temporal-Resolution into SDMs.......................... 45
5.3.1 Predictor Set Evaluation for H2k................................. 45
5.3.2 Temporal Approach Comparison..................................... 46
5.3.3 Spatio-Temporal Transferability.................................. 47
5.3.4 Suitability Projections.......................................... 47
III Insights 51
6 Summary....................................................................... 53
6.1 Article A1.............................................................. 53
6.2 Article A2.............................................................. 54
6.3 Article A3.............................................................. 56
7 Conclusions and Outlook....................................................... 59
References 65
Articles 81
A1 Repeatable high-resolution statistical downscaling through deep learning..... 83
A2 Downscaling CORDEX Through Deep Learning to Daily 1 km Multivariate Ensemble
in Complex Terrain............................................................. 103
A3 Integrating High-Temporal-Resolution Climate Projections into Species Distribu-
tion Model..................................................................... 127
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Naive semi-supervised deep learning med sammansättning av pseudo-klassificerare / Naive semi-supervised deep learning with an ensemble of pseudo-labelersKarlsson, Erik, Nordhammar, Gilbert January 2019 (has links)
Ett vanligt problem inom supervised learning är brist på taggad träningsdata. Naive semi-supervised deep learning är en träningsteknik som ämnar att mildra detta problem genom att generera pseudo-taggad data och därefter låta ett neuralt nätverk träna på denna samt en mindre mängd taggad data. Detta arbete undersöker om denna teknik kan förbättras genom användandet av röstning. Flera neurala nätverk tränas genom den framtagna tekniken, naive semi-supervised deep learning eller supervised learning och deras träffsäkerhet utvärderas därefter. Resultaten visade nästan enbart försämringar då röstning användes. Dock verkar inte förutsättningarna för röstning ha varit särskilt goda, vilket gör det svårt att dra en säker slutsats kring effekterna av röstning. Även om röstning inte gav förbättringar har NSSDL visat sig vara mycket effektiv. Det finns flera applikationsområden där tekniken i framtiden skulle kunna användas med goda resultat.
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MICROSCOPY IMAGE REGISTRATION, SYNTHESIS AND SEGMENTATIONChichen Fu (5929679) 10 June 2019 (has links)
<div>Fluorescence microscopy has emerged as a powerful tool for studying cell biology because it enables the acquisition of 3D image volumes deeper into tissue and the imaging of complex subcellular structures. Fluorescence microscopy images are frequently distorted by motion resulting from animal respiration and heartbeat which complicates the quantitative analysis of biological structures needed to characterize the structure and constituency of tissue volumes. This thesis describes a two pronged approach to quantitative analysis consisting of non-rigid registration and deep convolutional neural network segmentation. The proposed image registration method is capable of correcting motion artifacts in three dimensional fluorescence microscopy images collected over time. In particular, our method uses 3D B-Spline based nonrigid registration using a coarse-to-fine strategy to register stacks of images collected at different time intervals and 4D rigid registration to register 3D volumes over time. The results show that the proposed method has the ability of correcting global motion artifacts of sample tissues in four dimensional space, thereby revealing the motility of individual cells in the tissue.</div><div><br></div><div>We describe in thesis nuclei segmentation methods using deep convolutional neural networks, data augmentation to generate training images of different shapes and contrasts, a refinement process combining segmentation results of horizontal, frontal, and sagittal planes in a volume, and a watershed technique to enumerate the nuclei. Our results indicate that compared to 3D ground truth data, our method can successfully segment and count 3D nuclei. Furthermore, a microscopy image synthesis method based on spatially constrained cycle-consistent adversarial networks is used to efficiently generate training data. A 3D modified U-Net network is trained with a combination of Dice loss and binary cross entropy metrics to achieve accurate nuclei segmentation. A multi-task U-Net is utilized to resolve overlapping nuclei. This method was found to achieve high accuracy object-based and voxel-based evaluations.</div>
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MÉTODO DE CLASSIFICAÇÃO DE PRAGAS POR MEIO DE REDE NEURAL CONVOLUCIONAL PROFUNDARosa, Renan de Paula 19 November 2018 (has links)
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Previous issue date: 2018-11-19 / As pragas em lavouras causam prejuízos econômicos na agricultura, reduzindo a produção e consequentemente os lucros. O manejo de pragas é essencial, para reduzir estes prejuízos, e consiste na identificação e posterior controle desse tipo de ameaça. O controle é fundamentalmente dependente da identificação, pois é a partir dela que o manejo é feito. A identificação é feita visualmente, baseando-se nas características da praga. Essas características são inerentes e diferem de espécie para espécie. Devido à dificuldade da identificação, esse processo é realizado principalmente por profissionais especializados na área, o que acarreta na concentração do conhecimento. Esta dissertação apresenta uma metodologia para classificação de pragas por meio de técnicas de computação, onde um sistema computacional do tipo clienteservidor foi criado a fim de prover a classificação de pragas por meio de serviço, que é realizado pelo uso de rede neural convolucional baseada na arquitetura Inception V3. As pragas Anticarsia Gemmatalis, Helicoverpa armigera e Spodoptera Cosmioides, foram escolhidas para classificação por serem bastante comuns no estado do Paraná. A rede neural convolucional obteve índice de acerto de 92,5%. / Pests on crops cause economic damage to agriculture, reducing production and consequently profits. Pest management is essential to reduce these losses, and consists in the identification and subsequent control of this type of threat. Control is fundamentally dependent on identification, because management is done from it. The identification is made visually, based on the characteristics of the pest. These characteristics are inherent and differ from species to species. Due to the difficulty of identification, this process is carried out mainly by professionals specialized in the area, which entails the concentration of knowledge. This dissertation presents a methodology for pest classification by means of computational techniques, in which a client-server computational system was created in order to provide pest classification by means of a service, which is performed by the use of convolutional neural network based in the Inception V3 architecture. The pests Anticarsia Gemmatalis, Helicoverpa armigera and Spodoptera Cosmioides, were chosen for classification because they are quite common in the state of Paraná. The convolutional neural network obtained a success rate of 92.5%.
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Système de sécurité biométrique multimodal par imagerie, dédié au contrôle d’accès / Multimodal biometric security system based on vision, dedicated to access controlBonazza, Pierre 21 June 2019 (has links)
Les travaux de recherche de cette thèse consistent à mettre en place des solutions performantes et légères permettant de répondre aux problèmes de sécurisation de produits sensibles. Motivé par une collaboration avec différents acteurs au sein du projet Nuc-Track,le développement d'un système de sécurité biométrique, possiblement multimodal, mènera à une étude sur différentes caractéristiques biométriques telles que le visage, les empreintes digitales et le réseau vasculaire. Cette thèse sera axée sur une adéquation algorithme et architecture, dans le but de minimiser la taille de stockage des modèles d'apprentissages tout en garantissant des performances optimales. Cela permettra leur stockage sur un support personnel, respectant ainsi les normes de vie privée. / Research of this thesis consists in setting up efficient and light solutions to answer the problems of securing sensitive products. Motivated by a collaboration with various stakeholders within the Nuc-Track project, the development of a biometric security system, possibly multimodal, will lead to a study on various biometric features such as the face, fingerprints and the vascular network. This thesis will focus on an algorithm and architecture matching, with the aim of minimizing the storage size of the learning models while guaranteeing optimal performances. This will allow it to be stored on a personal support, thus respecting privacy standards.
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