684 research outputs found

    Meta-knowledge guided Bayesian optimization framework for robust crop yield estimation

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    Accurate pre-harvest crop yield estimation is vital for agricultural sustainability and economic stability. The existing yield estimating models exhibit deficiencies in insufficient examination of hyperparameters, lack of robustness, restricted transferability of meta-models, and uncertain generalizability when applied to agricultural data. This study presents a novel meta-knowledge-guided framework that leverages three diverse agricultural datasets and explores meta-knowledge transfer in frequent hyperparameter optimization scenarios. The framework’s approach involves base tasks using LightGBM and Bayesian Optimization, which automates hyperparameter optimization by eliminating the need for manual adjustments. Conducted rigorous experiments to analyze the meta-knowledge transformation of RGPE, SGPR, and TransBO algorithms, achieving impressive R2 values (0.8415, 0.9865, 0.9708) using rgpe_prf meta-knowledge transfer on diverse datasets. Furthermore, the framework yielded excellent results for mean squared error (MSE), mean absolute error (MAE), scaled MSE, and scaled MAE. These results emphasize the method’s significance, offering valuable insights for crop yield estimation, benefiting farmers and the agricultural sector

    An ensemble model for predictive energy performance:Closing the gap between actual and predicted energy use in residential buildings

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    The design stage of a building plays a pivotal role in influencing its life cycle and overall performance. Accurate predictions of a building's performance are crucial for informed decision-making, particularly in terms of energy performance, given the escalating global awareness of climate change and the imperative to enhance energy efficiency in buildings. However, a well-documented energy performance gap persists between actual and predicted energy consumption, primarily attributed to the unpredictable nature of occupant behavior.Existing methodologies for predicting and simulating occupant behavior in buildings frequently neglect or exclusively concentrate on particular behaviors, resulting in uncertainties in energy performance predictions. Machine learning approaches have exhibited increased accuracy in predicting occupant energy behavior, yet the majority of extant studies focus on specific behavior types rather than investigating the interactions among all contributing factors. This dissertation delves into the building energy performance gap, with a particular emphasis on the influence of occupants on energy performance. A comprehensive literature review scrutinizes machine learning models employed for predicting occupants' behavior in buildings and assesses their performance. The review uncovers knowledge gaps, as most studies are case-specific and lack a consolidated database to examine diverse behaviors across various building types.An ensemble model integrating occupant behavior parameters is devised to enhance the accuracy of energy performance predictions in residential buildings. Multiple algorithms are examined, with the selection of algorithms contingent upon evaluation metrics. The ensemble model is validated through a case study that compares actual energy consumption with the predictions of the ensemble model and an EnergyPlus simulation that takes occupant behavior factors into account.The findings demonstrate that the ensemble model provides considerably more accurate predictions of actual energy consumption compared to the EnergyPlus simulation. This dissertation also addresses the research limitations, including the reusability of the model and the requirement for additional datasets to bolster confidence in the model's applicability across diverse building types and occupant behavior patterns.In summary, this dissertation presents an ensemble model that endeavors to bridge the gap between actual and predicted energy usage in residential buildings by incorporating occupant behavior parameters, leading to more precise energy performance predictions and promoting superior energy management strategies

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    Privacy-preserving artificial intelligence in healthcare: Techniques and applications

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    There has been an increasing interest in translating artificial intelligence (AI) research into clinically-validated applications to improve the performance, capacity, and efficacy of healthcare services. Despite substantial research worldwide, very few AI-based applications have successfully made it to clinics. Key barriers to the widespread adoption of clinically validated AI applications include non-standardized medical records, limited availability of curated datasets, and stringent legal/ethical requirements to preserve patients' privacy. Therefore, there is a pressing need to improvise new data-sharing methods in the age of AI that preserve patient privacy while developing AI-based healthcare applications. In the literature, significant attention has been devoted to developing privacy-preserving techniques and overcoming the issues hampering AI adoption in an actual clinical environment. To this end, this study summarizes the state-of-the-art approaches for preserving privacy in AI-based healthcare applications. Prominent privacy-preserving techniques such as Federated Learning and Hybrid Techniques are elaborated along with potential privacy attacks, security challenges, and future directions. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.

    A Generative Framework for Low-Cost Result Validation of Outsourced Machine Learning Tasks

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    The growing popularity of Machine Learning (ML) has led to its deployment in various sensitive domains, which has resulted in significant research focused on ML security and privacy. However, in some applications, such as autonomous driving, integrity verification of the outsourced ML workload is more critical--a facet that has not received much attention. Existing solutions, such as multi-party computation and proof-based systems, impose significant computation overhead, which makes them unfit for real-time applications. We propose Fides, a novel framework for real-time validation of outsourced ML workloads. Fides features a novel and efficient distillation technique--Greedy Distillation Transfer Learning--that dynamically distills and fine-tunes a space and compute-efficient verification model for verifying the corresponding service model while running inside a trusted execution environment. Fides features a client-side attack detection model that uses statistical analysis and divergence measurements to identify, with a high likelihood, if the service model is under attack. Fides also offers a re-classification functionality that predicts the original class whenever an attack is identified. We devised a generative adversarial network framework for training the attack detection and re-classification models. The evaluation shows that Fides achieves an accuracy of up to 98% for attack detection and 94% for re-classification.Comment: 16 pages, 11 figure

    Learning from Audio, Vision and Language Modalities for Affect Recognition Tasks

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    The world around us as well as our responses to worldly events are multimodal in nature. For intelligent machines to integrate seamlessly into our world, it is imperative that they can process and derive useful information from multimodal signals. Such capabilities can be provided to machines by employing multimodal learning algorithms that consider both the individual characteristics of unimodal signals as well as the complementariness provided by multimodal signals. Based on the number of modalities available during the training and testing phases, learning algorithms can be of three categories: unimodal trained and unimodal tested, multimodal trained and multimodal tested, and multimodal trained and unimodal tested algorithms. This thesis provides three contributions, one for each category and focuses on three modalities that are important for human-human and human-machine communication, namely, audio (paralinguistic speech), vision (facial expressions) and language (linguistic speech) signals. For several applications, either due to hardware limitations or deployment specifications, unimodal trained and tested systems suffice. Our first contribution, for the unimodal trained and unimodal tested category, is an end-to-end deep neural network that uses raw speech signals as input for a computational paralinguistic task, namely, verbal conflict intensity estimation. Our model, which uses a convolutional recurrent architecture equipped with attention mechanism to focus on task-relevant instances of the input speech signal, eliminates the need for task-specific meta data or domain knowledge based manual refinement of hand-crafted generic features. The second contribution, for the multimodal trained and multimodal tested category, is a multimodal fusion framework that exploits both cross (inter) and intra-modal interactions for categorical emotion recognition from audiovisual clips. We explore the effectiveness of two types of attention mechanisms, namely, intra and cross-modal attention by creating two versions of our fusion framework. In many applications, multimodal signals might be available during model training phase, yet we cannot expect the availability of all modality signals during testing phase. Our third contribution addresses this situation wherein we propose a framework for cross-modal learning where paired audio-visual instances are used during training to develop test-time stand-alone unimodal models

    Behavior quantification as the missing link between fields: Tools for digital psychiatry and their role in the future of neurobiology

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    The great behavioral heterogeneity observed between individuals with the same psychiatric disorder and even within one individual over time complicates both clinical practice and biomedical research. However, modern technologies are an exciting opportunity to improve behavioral characterization. Existing psychiatry methods that are qualitative or unscalable, such as patient surveys or clinical interviews, can now be collected at a greater capacity and analyzed to produce new quantitative measures. Furthermore, recent capabilities for continuous collection of passive sensor streams, such as phone GPS or smartwatch accelerometer, open avenues of novel questioning that were previously entirely unrealistic. Their temporally dense nature enables a cohesive study of real-time neural and behavioral signals. To develop comprehensive neurobiological models of psychiatric disease, it will be critical to first develop strong methods for behavioral quantification. There is huge potential in what can theoretically be captured by current technologies, but this in itself presents a large computational challenge -- one that will necessitate new data processing tools, new machine learning techniques, and ultimately a shift in how interdisciplinary work is conducted. In my thesis, I detail research projects that take different perspectives on digital psychiatry, subsequently tying ideas together with a concluding discussion on the future of the field. I also provide software infrastructure where relevant, with extensive documentation. Major contributions include scientific arguments and proof of concept results for daily free-form audio journals as an underappreciated psychiatry research datatype, as well as novel stability theorems and pilot empirical success for a proposed multi-area recurrent neural network architecture.Comment: PhD thesis cop

    Point Cloud Processing for Environmental Analysis in Autonomous Driving using Deep Learning

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    Autonomous self-driving cars need a very precise perception system of their environment, working for every conceivable scenario. Therefore, different kinds of sensor types, such as lidar scanners, are in use. This thesis contributes highly efficient algorithms for 3D object recognition to the scientific community. It provides a Deep Neural Network with specific layers and a novel loss to safely localize and estimate the orientation of objects from point clouds originating from lidar sensors. First, a single-shot 3D object detector is developed that outputs dense predictions in only one forward pass. Next, this detector is refined by fusing complementary semantic features from cameras and joint probabilistic tracking to stabilize predictions and filter outliers. The last part presents an evaluation of data from automotive-grade lidar scanners. A Generative Adversarial Network is also being developed as an alternative for target-specific artificial data generation.One of the main objectives of leading automotive companies is autonomous self-driving cars. They need a very precise perception system of their environment, working for every conceivable scenario. Therefore, different kinds of sensor types are in use. Besides cameras, lidar scanners became very important. The development in that field is significant for future applications and system integration because lidar offers a more accurate depth representation, independent from environmental illumination. Especially algorithms and machine learning approaches, including Deep Learning and Artificial Intelligence based on raw laser scanner data, are very important due to the long range and three-dimensional resolution of the measured point clouds. Consequently, a broad field of research with many challenges and unsolved tasks has been established. This thesis aims to address this deficit and contribute highly efficient algorithms for 3D object recognition to the scientific community. It provides a Deep Neural Network with specific layers and a novel loss to safely localize and estimate the orientation of objects from point clouds. First, a single shot 3D object detector is developed that outputs dense predictions in only one forward pass. Next, this detector is refined by fusing complementary semantic features from cameras and a joint probabilistic tracking to stabilize predictions and filter outliers. In the last part, a concept for deployment into an existing test vehicle focuses on the semi-automated generation of a suitable dataset. Subsequently, an evaluation of data from automotive-grade lidar scanners is presented. A Generative Adversarial Network is also being developed as an alternative for target-specific artificial data generation. Experiments on the acquired application-specific and benchmark datasets show that the presented methods compete with a variety of state-of-the-art algorithms while being trimmed down to efficiency for use in self-driving cars. Furthermore, they include an extensive set of standard evaluation metrics and results to form a solid baseline for future research.Eines der Hauptziele führender Automobilhersteller sind autonome Fahrzeuge. Sie benötigen ein sehr präzises System für die Wahrnehmung der Umgebung, dass für jedes denkbare Szenario überall auf der Welt funktioniert. Daher sind verschiedene Arten von Sensoren im Einsatz, sodass neben Kameras u. a. auch Lidar Sensoren ein wichtiger Bestandteil sind. Die Entwicklung auf diesem Gebiet ist für künftige Anwendungen von höchster Bedeutung, da Lidare eine genauere, von der Umgebungsbeleuchtung unabhängige, Tiefendarstellung bieten. Insbesondere Algorithmen und maschinelle Lernansätze wie Deep Learning, die Rohdaten über Lernzprozesse direkt verarbeiten können, sind aufgrund der großen Reichweite und der dreidimensionalen Auflösung der gemessenen Punktwolken sehr wichtig. Somit hat sich ein weites Forschungsfeld mit vielen Herausforderungen und ungelösten Problemen etabliert. Diese Arbeit zielt darauf ab, dieses Defizit zu verringern und effiziente Algorithmen zur 3D-Objekterkennung zu entwickeln. Sie stellt ein tiefes Neuronales Netzwerk mit spezifischen Schichten und einer neuartigen Fehlerfunktion zur sicheren Lokalisierung und Schätzung der Orientierung von Objekten aus Punktwolken bereit. Zunächst wird ein 3D-Detektor entwickelt, der in nur einem Vorwärtsdurchlauf aus einer Punktwolke alle Objekte detektiert. Anschließend wird dieser Detektor durch die Fusion von komplementären semantischen Merkmalen aus Kamerabildern und einem gemeinsamen probabilistischen Tracking verfeinert, um die Detektionen zu stabilisieren und Ausreißer zu filtern. Im letzten Teil wird ein Konzept für den Einsatz in einem bestehenden Testfahrzeug vorgestellt, das sich auf die halbautomatische Generierung eines geeigneten Datensatzes konzentriert. Hierbei wird eine Auswertung auf Daten von Automotive-Lidaren vorgestellt. Als Alternative zur zielgerichteten künstlichen Datengenerierung wird ein weiteres generatives Neuronales Netzwerk untersucht. Experimente mit den erzeugten anwendungsspezifischen- und Benchmark-Datensätzen zeigen, dass sich die vorgestellten Methoden mit dem Stand der Technik messen können und gleichzeitig auf Effizienz für den Einsatz in selbstfahrenden Autos optimiert sind. Darüber hinaus enthalten sie einen umfangreichen Satz an Evaluierungsmetriken und -ergebnissen, die eine solide Grundlage für die zukünftige Forschung bilden
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