Interactive Visual Analytics for Agent-Based Simulation: Street-Crossing Behavior at Signalized Pedestrian Crossing

To design a pedestrian crossing area reasonably can be a demanding task for traffic planners. There are several challenges, including determining the appropriate dimensions, and ensuring that pedestrians are exposed to the least risks. Pedestrian safety is especially obscure to analyze, given that many people in Stockholm cross the street illegally by running against the red light. To cope with these challenges, computational approaches of trajectory data visual analytics can be used to support the analytical reasoning process. However, it remains an unexplored field regarding how to visualize and communicate the street-crossing spatio-temporal data effectively. Moreover, the rendering also needs to deal with a growing data size for a more massive number of people. This thesis proposes a web-based interactive visual analytics tool for pedestrians' street-crossing behavior under various flow rates. The visualization methodology is also presented, which is then evaluated to have achieved satisfying communication and rendering effectiveness for maximal 180 agents over 100 seconds. In terms of the visualization scenario, pedestrians either wait for the red light or cross the street illegally; all people can choose to stop by a buffer island before they finish crossing. The visualization enables the analysis under multiple flow rates for 1) pedestrian movement, 2) space utilization, 3) crossing frequency in time-series, and 4) illegal frequency. Additionally, to acquire the initial trajectory data, Optimal Reciprocal Collision Avoidance (ORCA) algorithm is engaged in the crowd simulation. Then different visualization techniques are utilized to comply with user demands, including map animation, data aggregation, and time-series graph

NOIR: Neural Signal Operated Intelligent Robots for Everyday Activities

We present Neural Signal Operated Intelligent Robots (NOIR), a general-purpose, intelligent brain-robot interface system that enables humans to command robots to perform everyday activities through brain signals. Through this interface, humans communicate their intended objects of interest and actions to the robots using electroencephalography (EEG). Our novel system demonstrates success in an expansive array of 20 challenging, everyday household activities, including cooking, cleaning, personal care, and entertainment. The effectiveness of the system is improved by its synergistic integration of robot learning algorithms, allowing for NOIR to adapt to individual users and predict their intentions. Our work enhances the way humans interact with robots, replacing traditional channels of interaction with direct, neural communication. Project website: https://noir-corl.github.io/

A Unified Framework for Gradient-based Hyperparameter Optimization and Meta-learning

Machine learning algorithms and systems are progressively becoming part of our societies, leading to a growing need of building a vast multitude of accurate, reliable and interpretable models which should possibly exploit similarities among tasks. Automating segments of machine learning itself seems to be a natural step to undertake to deliver increasingly capable systems able to perform well in both the big-data and the few-shot learning regimes. Hyperparameter optimization (HPO) and meta-learning (MTL) constitute two building blocks of this growing effort. We explore these two topics under a unifying perspective, presenting a mathematical framework linked to bilevel programming that captures existing similarities and translates into procedures of practical interest rooted in algorithmic differentiation. We discuss the derivation, applicability and computational complexity of these methods and establish several approximation properties for a class of objective functions of the underlying bilevel programs. In HPO, these algorithms generalize and extend previous work on gradient-based methods. In MTL, the resulting framework subsumes classic and emerging strategies and provides a starting basis from which to build and analyze novel techniques. A series of examples and numerical simulations offer insight and highlight some limitations of these approaches. Experiments on larger-scale problems show the potential gains of the proposed methods in real-world applications. Finally, we develop two extensions of the basic algorithms apt to optimize a class of discrete hyperparameters (graph edges) in an application to relational learning and to tune online learning rate schedules for training neural network models, an old but crucially important issue in machine learning

Robust and Adversarial Data Mining

In the domain of data mining and machine learning, researchers have made significant contributions in developing algorithms handling clustering and classification problems. We develop algorithms under assumptions that are not met by previous works. (i) In adversarial learning, which is the study of machine learning techniques deployed in non-benign environments. We design an algorithm to show how a classifier should be designed to be robust against sparse adversarial attacks. Our main insight is that sparse feature attacks are best defended by designing classifiers which use L1 regularizers. (ii) The different properties between L1 (Lasso) and L2 (Tikhonov or Ridge) regularization has been studied extensively. However, given a data set, principle to follow in terms of choosing the suitable regularizer is yet to be developed. We use mathematical properties of the two regularization methods followed by detailed experimentation to understand their impact based on four characteristics. (iii) The identification of anomalies is an inherent component of knowledge discovery. In lots of cases, the number of features of a data set can be traced to a much smaller set of features. We claim that algorithms applied in a latent space are more robust. This can lead to more accurate results, and potentially provide a natural medium to explain and describe outliers. (iv) We also apply data mining techniques on health care industry. In a lot cases, health insurance companies cover unnecessary costs carried out by healthcare providers. The potential adversarial behaviours of surgeon physicians are addressed. We describe a specific con- text of private healthcare in Australia and describe our social network based approach (applied to health insurance claims) to understand the nature of collaboration among doctors treating hospital inpatients and explore the impact of collaboration on cost and quality of care. (v) We further develop models that predict the behaviours of orthopaedic surgeons in regard to surgery type and use of prosthetic device. An important feature of these models is that they can not only predict the behaviours of surgeons but also provide explanation for the predictions

Deep Learning Architectures for Heterogeneous Face Recognition

Face recognition has been one of the most challenging areas of research in biometrics and computer vision. Many face recognition algorithms are designed to address illumination and pose problems for visible face images. In recent years, there has been significant amount of research in Heterogeneous Face Recognition (HFR). The large modality gap between faces captured in different spectrum as well as lack of training data makes heterogeneous face recognition (HFR) quite a challenging problem. In this work, we present different deep learning frameworks to address the problem of matching non-visible face photos against a gallery of visible faces. Algorithms for thermal-to-visible face recognition can be categorized as cross-spectrum feature-based methods, or cross-spectrum image synthesis methods. In cross-spectrum feature-based face recognition a thermal probe is matched against a gallery of visible faces corresponding to the real-world scenario, in a feature subspace. The second category synthesizes a visible-like image from a thermal image which can then be used by any commercial visible spectrum face recognition system. These methods also beneficial in the sense that the synthesized visible face image can be directly utilized by existing face recognition systems which operate only on the visible face imagery. Therefore, using this approach one can leverage the existing commercial-off-the-shelf (COTS) and government-off-the-shelf (GOTS) solutions. In addition, the synthesized images can be used by human examiners for different purposes. There are some informative traits, such as age, gender, ethnicity, race, and hair color, which are not distinctive enough for the sake of recognition, but still can act as complementary information to other primary information, such as face and fingerprint. These traits, which are known as soft biometrics, can improve recognition algorithms while they are much cheaper and faster to acquire. They can be directly used in a unimodal system for some applications. Usually, soft biometric traits have been utilized jointly with hard biometrics (face photo) for different tasks in the sense that they are considered to be available both during the training and testing phases. In our approaches we look at this problem in a different way. We consider the case when soft biometric information does not exist during the testing phase, and our method can predict them directly in a multi-tasking paradigm. There are situations in which training data might come equipped with additional information that can be modeled as an auxiliary view of the data, and that unfortunately is not available during testing. This is the LUPI scenario. We introduce a novel framework based on deep learning techniques that leverages the auxiliary view to improve the performance of recognition system. We do so by introducing a formulation that is general, in the sense that can be used with any visual classifier. Every use of auxiliary information has been validated extensively using publicly available benchmark datasets, and several new state-of-the-art accuracy performance values have been set. Examples of application domains include visual object recognition from RGB images and from depth data, handwritten digit recognition, and gesture recognition from video. We also design a novel aggregation framework which optimizes the landmark locations directly using only one image without requiring any extra prior which leads to robust alignment given arbitrary face deformations. Three different approaches are employed to generate the manipulated faces and two of them perform the manipulation via the adversarial attacks to fool a face recognizer. This step can decouple from our framework and potentially used to enhance other landmark detectors. Aggregation of the manipulated faces in different branches of proposed method leads to robust landmark detection. Finally we focus on the generative adversarial networks which is a very powerful tool in synthesizing a visible-like images from the non-visible images. The main goal of a generative model is to approximate the true data distribution which is not known. In general, the choice for modeling the density function is challenging. Explicit models have the advantage of explicitly calculating the probability densities. There are two well-known implicit approaches, namely the Generative Adversarial Network (GAN) and Variational AutoEncoder (VAE) which try to model the data distribution implicitly. The VAEs try to maximize the data likelihood lower bound, while a GAN performs a minimax game between two players during its optimization. GANs overlook the explicit data density characteristics which leads to undesirable quantitative evaluations and mode collapse. This causes the generator to create similar looking images with poor diversity of samples. In the last chapter of thesis, we focus to address this issue in GANs framework

Adapting by copying. Towards a sustainable machine learning

[eng] Despite the rapid growth of machine learning in the past decades, deploying automated decision making systems in practice remains a challenge for most companies. On an average day, data scientists face substantial barriers to serving models into production. Production environments are complex ecosystems, still largely based on on-premise technology, where modifications are timely and costly. Given the rapid pace with which the machine learning environment changes these days, companies struggle to stay up-to-date with the latest software releases, the changes in regulation and the newest market trends. As a result, machine learning often fails to deliver according to expectations. And more worryingly, this can result in unwanted risks for users, for the company itself and even for the society as a whole, insofar the negative impact of these risks is perpetuated in time. In this context, adaptation is an instrument that is both necessary and crucial for ensuring a sustainable deployment of industrial machine learning. This dissertation is devoted to developing theoretical and practical tools to enable adaptation of machine learning models in company production environments. More precisely, we focus on devising mechanisms to exploit the knowledge acquired by models to train future generations that are better fit to meet the stringent demands of a changing ecosystem. We introduce copying as a mechanism to replicate the decision behaviour of a model using another that presents differential characteristics, in cases where access to both the models and their training data are restricted. We discuss the theoretical implications of this methodology and show how it can be performed and evaluated in practice. Under the conceptual framework of actionable accountability we also explore how copying can be used to ensure risk mitigation in circumstances where deployment of a machine learning solution results in a negative impact to individuals or organizations.[spa] A pesar del rápido crecimiento del aprendizaje automático en últimas décadas, la implementación de sistemas automatizados para la toma de decisiones sigue siendo un reto para muchas empresas. Los científicos de datos se enfrentan a diario a numerosas barreras a la hora de desplegar los modelos en producción. Los entornos de producción son ecosistemas complejos, mayoritariamente basados en tecnologías on- premise, donde los cambios son costosos. Es por eso que las empresas tienen serias dificultades para mantenerse al día con las últimas versiones de software, los cambios en la regulación vigente o las nuevas tendencias del mercado. Como consecuencia, el rendimiento del aprendizaje automático está a menudo muy por debajo de las expectativas. Y lo que es más preocupante, esto puede derivar en riesgos para los usuarios, para las propias empresas e incluso para la sociedad en su conjunto, en la medida en que el impacto negativo de dichos riesgos se perpetúe en el tiempo. En este contexto, la adaptación se revela como un elemento necesario e imprescindible para asegurar la sostenibilidad del desarrollo industrial del aprendizaje automático. Este trabajo está dedicado a desarrollar las herramientas teóricas y prácticas necesarias para posibilitar la adaptación de los modelos de aprendizaje automático en entornos de producción. En concreto, nos centramos en concebir mecanismos que permitan reutilizar el conocimiento adquirido por los modelos para entrenar futuras generaciones que estén mejor preparadas para satisfacer las demandas de un entorno altamente cambiante. Introducimos la idea de copiar, como un mecanismo que permite replicar el comportamiento decisorio de un modelo utilizando un segundo que presenta características diferenciales, en escenarios donde el acceso tanto a los datos como al propio modelo está restringido. Es en este contexto donde discutimos las implicaciones teóricas de esta metodología y demostramos como las copias pueden ser entrenadas y evaluadas en la práctica. Bajo el marco de la responsabilidad accionable, exploramos también cómo las copias pueden explotarse como herramienta para la mitigación de riesgos en circunstancias en que el despliegue de una solución basada en el aprendizaje automático pueda tener un impacto negativo sobre las personas o las organizaciones

Automated decision making and problem solving. Volume 2: Conference presentations

Related topics in artificial intelligence, operations research, and control theory are explored. Existing techniques are assessed and trends of development are determined

Geographic Information Systems and Science

Geographic information science (GISc) has established itself as a collaborative information-processing scheme that is increasing in popularity. Yet, this interdisciplinary and/or transdisciplinary system is still somewhat misunderstood. This book talks about some of the GISc domains encompassing students, researchers, and common users. Chapters focus on important aspects of GISc, keeping in mind the processing capability of GIS along with the mathematics and formulae involved in getting each solution. The book has one introductory and eight main chapters divided into five sections. The first section is more general and focuses on what GISc is and its relation to GIS and Geography, the second is about location analytics and modeling, the third on remote sensing data analysis, the fourth on big data and augmented reality, and, finally, the fifth looks over volunteered geographic information.info:eu-repo/semantics/publishedVersio

AI alignment and generalization in deep learning

This thesis covers a number of works in deep learning aimed at understanding and improving generalization abilities of deep neural networks (DNNs). DNNs achieve unrivaled performance in a growing range of tasks and domains, yet their behavior during learning and deployment remains poorly understood. They can also be surprisingly brittle: in-distribution generalization can be a poor predictor of behavior or performance under distributional shifts, which typically cannot be avoided in practice. While these limitations are not unique to DNNs -- and indeed are likely to be challenges facing any AI systems of sufficient complexity -- the prevalence and power of DNNs makes them particularly worthy of study. I frame these challenges within the broader context of "AI Alignment": a nascent field focused on ensuring that AI systems behave in accordance with their user's intentions. While making AI systems more intelligent or capable can help make them more aligned, it is neither necessary nor sufficient for alignment. However, being able to align state-of-the-art AI systems (e.g. DNNs) is of great social importance in order to avoid undesirable and unsafe behavior from advanced AI systems. Without progress in AI Alignment, advanced AI systems might pursue objectives at odds with human survival, posing an existential risk (``x-risk'') to humanity. A core tenet of this thesis is that the achieving high performance on machine learning benchmarks if often a good indicator of AI systems' capabilities, but not their alignment. This is because AI systems often achieve high performance in unexpected ways that reveal the limitations of our performance metrics, and more generally, our techniques for specifying our intentions. Learning about human intentions using DNNs shows some promise, but DNNs are still prone to learning to solve tasks using concepts of "features" very different from those which are salient to humans. Indeed, this is a major source of their poor generalization on out-of-distribution data. By better understanding the successes and failures of DNN generalization and current methods of specifying our intentions, we aim to make progress towards deep-learning based AI systems that are able to understand users' intentions and act accordingly.Cette thèse discute quelques travaux en apprentissage profond visant à comprendre et à améliorer les capacités de généralisation des réseaux de neurones profonds (DNN). Les DNNs atteignent des performances inégalées dans un éventail croissant de tâches et de domaines, mais leur comportement pendant l'apprentissage et le déploiement reste mal compris. Ils peuvent également être étonnamment fragiles: la généralisation dans la distribution peut être un mauvais prédicteur du comportement ou de la performance lors de changements de distribution, ce qui ne peut généralement pas être évité dans la pratique. Bien que ces limitations ne soient pas propres aux DNN - et sont en effet susceptibles de constituer des défis pour tout système d'IA suffisamment complexe - la prévalence et la puissance des DNN les rendent particulièrement dignes d'étude. J'encadre ces défis dans le contexte plus large de «l'alignement de l'IA»: un domaine naissant axé sur la garantie que les systèmes d'IA se comportent conformément aux intentions de leurs utilisateurs. Bien que rendre les systèmes d'IA plus intelligents ou capables puisse aider à les rendre plus alignés, cela n'est ni nécessaire ni suffisant pour l'alignement. Cependant, être capable d'aligner les systèmes d'IA de pointe (par exemple les DNN) est d'une grande importance sociale afin d'éviter les comportements indésirables et dangereux des systèmes d'IA avancés. Sans progrès dans l'alignement de l'IA, les systèmes d'IA avancés pourraient poursuivre des objectifs contraires à la survie humaine, posant un risque existentiel («x-risque») pour l'humanité. L'un des principes fondamentaux de cette thèse est que l'obtention de hautes performances sur les repères d'apprentissage automatique est souvent un bon indicateur des capacités des systèmes d'IA, mais pas de leur alignement. En effet, les systèmes d'IA atteignent souvent des performances élevées de manière inattendue, ce qui révèle les limites de nos mesures de performance et, plus généralement, de nos techniques pour spécifier nos intentions. L'apprentissage des intentions humaines à l'aide des DNN est quelque peu prometteur, mais les DNN sont toujours enclins à apprendre à résoudre des tâches en utilisant des concepts de «caractéristiques» très différents de ceux qui sont saillants pour les humains. En effet, c'est une source majeure de leur mauvaise généralisation sur les données hors distribution. En comprenant mieux les succès et les échecs de la généralisation DNN et les méthodes actuelles de spécification de nos intentions, nous visons à progresser vers des systèmes d'IA basés sur l'apprentissage en profondeur qui sont capables de comprendre les intentions des utilisateurs et d'agir en conséquence