Statistical Learning
State-space deep Gaussian processes with applications
This thesis is mainly concerned with state-space approaches for solving deep (temporal) Gaussian process (DGP) regression problems. More specifically, we represent DGPs as hierarchically composed systems of stochastic differential equations (SDEs), and we consequently solve the DGP regression problem by using state-space filtering and smoothing methods. The resulting state-space DGP (SS-DGP) models generate a rich class of priors compatible with modelling a number of irregular signals/functions. Moreover, due to their Markovian structure, SS-DGPs regression problems can be solved efficiently by using Bayesian filtering and smoothing methods. The second contribution of this thesis is that we solve continuous-discrete Gaussian filtering and smoothing problems by using the Taylor moment expansion (TME) method. This induces a class of filters and smoothers that can be asymptotically exact in predicting the mean and covariance of stochastic differential equations (SDEs) solutions. Moreover, the TME method and TME filters and smoothers are compatible with simulating SS-DGPs and solving their regression problems. Lastly, this thesis features a number of applications of state-space (deep) GPs. These applications mainly include, (i) estimation of unknown drift functions of SDEs from partially observed trajectories and (ii) estimation of spectro-temporal features of signals.
Conditional Object-Centric Learning from Video
Kipf, Thomas, Elsayed, Gamaleldin F., Mahendran, Aravindh, Stone, Austin, Sabour, Sara, Heigold, Georg, Jonschkowski, Rico, Dosovitskiy, Alexey, Greff, Klaus
Object-centric representations are a promising path toward more systematic generalization by providing flexible abstractions upon which compositional world models can be built. Recent work on simple 2D and 3D datasets has shown that models with object-centric inductive biases can learn to segment and represent meaningful objects from the statistical structure of the data alone without the need for any supervision. However, such fully-unsupervised methods still fail to scale to diverse realistic data, despite the use of increasingly complex inductive biases such as priors for the size of objects or the 3D geometry of the scene. In this paper, we instead take a weakly-supervised approach and focus on how 1) using the temporal dynamics of video data in the form of optical flow and 2) conditioning the model on simple object location cues can be used to enable segmenting and tracking objects in significantly more realistic synthetic data. We introduce a sequential extension to Slot Attention which we train to predict optical flow for realistic looking synthetic scenes and show that conditioning the initial state of this model on a small set of hints, such as center of mass of objects in the first frame, is sufficient to significantly improve instance segmentation. These benefits generalize beyond the training distribution to novel objects, novel backgrounds, and to longer video sequences. We also find that such initial-state-conditioning can be used during inference as a flexible interface to query the model for specific objects or parts of objects, which could pave the way for a range of weakly-supervised approaches and allow more effective interaction with trained models.
ViCE: Self-Supervised Visual Concept Embeddings as Contextual and Pixel Appearance Invariant Semantic Representations
Karlsson, Robin, Hayashi, Tomoki, Fujii, Keisuke, Carballo, Alexander, Ohtani, Kento, Takeda, Kazuya
This work presents a self-supervised method to learn dense semantically rich visual concept embeddings for images inspired by methods for learning word embeddings in NLP. Our method improves on prior work by generating more expressive embeddings and by being applicable for high-resolution images. Viewing the generation of natural images as a stochastic process where a set of latent visual concepts give rise to observable pixel appearances, our method is formulated to learn the inverse mapping from pixels to concepts. Our method greatly improves the effectiveness of self-supervised learning for dense embedding maps by introducing superpixelization as a natural hierarchical step up from pixels to a small set of visually coherent regions. Additional contributions are regional contextual masking with nonuniform shapes matching visually coherent patches and complexity-based view sampling inspired by masked language models. The enhanced expressiveness of our dense embeddings is demonstrated by significantly improving the state-of-the-art representation quality benchmarks on COCO (+12.94 mIoU, +87.6\%) and Cityscapes (+16.52 mIoU, +134.2\%). Results show favorable scaling and domain generalization properties not demonstrated by prior work.
Dictionary-based Low-Rank Approximations and the Mixed Sparse Coding problem
Constrained tensor and matrix factorization models allow to extract interpretable patterns from multiway data. Therefore identifiability properties and efficient algorithms for constrained low-rank approximations are nowadays important research topics. This work deals with columns of factor matrices of a low-rank approximation being sparse in a known and possibly overcomplete basis, a model coined as Dictionary-based Low-Rank Approximation (DLRA). While earlier contributions focused on finding factor columns inside a dictionary of candidate columns, i.e. one-sparse approximations, this work is the first to tackle DLRA with sparsity larger than one. I propose to focus on the sparse-coding subproblem coined Mixed Sparse-Coding (MSC) that emerges when solving DLRA with an alternating optimization strategy. Several algorithms based on sparse-coding heuristics (greedy methods, convex relaxations) are provided to solve MSC. The performance of these heuristics is evaluated on simulated data. Then, I show how to adapt an efficient MSC solver based on the LASSO to compute Dictionary-based Matrix Factorization and Canonical Polyadic Decomposition in the context of hyperspectral image processing and chemometrics. These experiments suggest that DLRA extends the modeling capabilities of low-rank approximations, helps reducing estimation variance and enhances the identifiability and interpretability of estimated factors.
Improved Fine-tuning by Leveraging Pre-training Data: Theory and Practice
Liu, Ziquan, Xu, Yi, Xu, Yuanhong, Qian, Qi, Li, Hao, Chan, Antoni, Jin, Rong
As a dominant paradigm, fine-tuning a pre-trained model on the target data is widely used in many deep learning applications, especially for small data sets. However, recent studies have empirically shown that training from scratch has the final performance that is no worse than this pre-training strategy once the number of training iterations is increased in some vision tasks. In this work, we revisit this phenomenon from the perspective of generalization analysis which is popular in learning theory. Our result reveals that the final prediction precision may have a weak dependency on the pre-trained model especially in the case of large training iterations. The observation inspires us to leverage pre-training data for fine-tuning, since this data is also available for fine-tuning. The generalization result of using pre-training data shows that the final performance on a target task can be improved when the appropriate pre-training data is included in fine-tuning. With the insight of the theoretical finding, we propose a novel selection strategy to select a subset from pre-training data to help improve the generalization on the target task. Extensive experimental results for image classification tasks on 8 benchmark data sets verify the effectiveness of the proposed data selection based fine-tuning pipeline.
Multi-task manifold learning for small sample size datasets
Ishibashi, Hideaki, Higa, Kazushi, Furukawa, Tetsuo
In this study, we develop a method for multi-task manifold learning. The method aims to improve the performance of manifold learning for multiple tasks, particularly when each task has a small number of samples. Furthermore, the method also aims to generate new samples for new tasks, in addition to new samples for existing tasks. In the proposed method, we use two different types of information transfer: instance transfer and model transfer. For instance transfer, datasets are merged among similar tasks, whereas for model transfer, the manifold models are averaged among similar tasks. For this purpose, the proposed method consists of a set of generative manifold models corresponding to the tasks, which are integrated into a general model of a fiber bundle. We applied the proposed method to artificial datasets and face image sets, and the results showed that the method was able to estimate the manifolds, even for a tiny number of samples.
Deep metric learning improves lab of origin prediction of genetically engineered plasmids
Soares, Igor M., Camargo, Fernando H. F., Marques, Adriano, Crook, Oliver M.
Genome engineering is undergoing unprecedented development and is now becoming widely available. To ensure responsible biotechnology innovation and to reduce misuse of engineered DNA sequences, it is vital to develop tools to identify the lab-of-origin of engineered plasmids. Genetic engineering attribution (GEA), the ability to make sequence-lab associations, would support forensic experts in this process. Here, we propose a method, based on metric learning, that ranks the most likely labs-of-origin whilst simultaneously generating embeddings for plasmid sequences and labs. These embeddings can be used to perform various downstream tasks, such as clustering DNA sequences and labs, as well as using them as features in machine learning models. Our approach employs a circular shift augmentation approach and is able to correctly rank the lab-of-origin $90\%$ of the time within its top 10 predictions - outperforming all current state-of-the-art approaches. We also demonstrate that we can perform few-shot-learning and obtain $76\%$ top-10 accuracy using only $10\%$ of the sequences. This means, we outperform the previous CNN approach using only one-tenth of the data. We also demonstrate that we are able to extract key signatures in plasmid sequences for particular labs, allowing for an interpretable examination of the model's outputs.
Autonomous bot with ML-based reactive navigation for indoor environment
Srivastava, Yash, Singh, Saumya, Ibrahim, S. P. Syed
Local or reactive navigation is essential for autonomous mobile robots which operate in an indoor environment. Techniques such as SLAM, computer vision require significant computational power which increases cost. Similarly, using rudimentary methods makes the robot susceptible to inconsistent behavior. This paper aims to develop a robot that balances cost and accuracy by using machine learning to predict the best obstacle avoidance move based on distance inputs from four ultrasonic sensors that are strategically mounted on the front, front-left, front-right, and back of the robot. The underlying hardware consists of an Arduino Uno and a Raspberry Pi 3B. The machine learning model is first trained on the data collected by the robot. Then the Arduino continuously polls the sensors and calculates the distance values, and in case of critical need for avoidance, a suitable maneuver is made by the Arduino. In other scenarios, sensor data is sent to the Raspberry Pi using a USB connection and the machine learning model generates the best move for navigation, which is sent to the Arduino for driving motors accordingly. The system is mounted on a 2-WD robot chassis and tested in a cluttered indoor setting with most impressive results.
Low Code and No Code: The Future of Artificial Intelligence โ Bestgamingpro
Will low code apps go any higher? The jury is still out on how high this will all go. Low code and no code might even help business users build AI-driven applications, according to some experts. "Low and no code platforms make it feasible for businesses to deploy artificial intelligence without having to hire an army of pricey developers and data scientists," writes Jonathan Reilly in Harvard Business Review. "Removing friction from adoption will help unleash the power of AI across all industries and allow non-specialists to literally predict the future. In time, no-code AI platforms will be as ubiquitous as word-processing or spreadsheet software is today," Use tools like Amazon AWS to make it easier for you to consume AI services.
2021 Data Science/MachineLearning Project Deployment Mastery
End-to-End Data Science and Machine Learning (Right from learning the basics to building the models to deploying the models) Learn Through More Than 20 Projects and Assignments Master Machine Learning With Python Learn How to Deploy Machine Learning Models Practical Hands-On Data Science Projects Mastery Build And Deploy Machine Learning models On Flask, Heroku, Streamlit, AWS,Google Cloud, Microsoft Azure Create Robust Machine Learning Models with CatBoost,XGBoost, LightGbm Learn Different Machine Learning Algorithms such as Linear And Logistic regression, Naive Bayes,KNN,SVM,K-means, etc. Deal With Data Imbalance (Upsampling/Downsampling/SMOTE) Gain Confidence In Performing Exploratory Data Analysis (EDA) Choose The Right Machine Learning Model For Your Problem Statement Access To Exclusive Community To Learn With Others And Answer Your Queries Learn The Necessary Statistics Master Data Analysis This course is a beginner to advance level course with all the tutorials on the lessons covered in the projects included If you are a complete beginner, you have all the lessons from introduction to python to building projects and deployment. If you already have have the basics, we have more than 20 projects and deployment for you to practice. If you are a complete beginner, you have all the lessons from introduction to python to building projects and deployment. If you already have have the basics, we have more than 20 projects and deployment for you to practice. Then this course is for you!!