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 Deep Learning


Contrastive learning of global and local features for medical image segmentation with limited annotations

arXiv.org Machine Learning

A key requirement for the success of supervised deep learning is a large labeled dataset - a condition that is difficult to meet in medical image analysis. Self-supervised learning (SSL) can help in this regard by providing a strategy to pre-train a neural network with unlabeled data, followed by fine-tuning for a downstream task with limited annotations. Contrastive learning, a particular variant of SSL, is a powerful technique for learning image-level representations. In this work, we propose strategies for extending the contrastive learning framework for segmentation of volumetric medical images in the semi-supervised setting with limited annotations, by leveraging domain-specific and problem-specific cues. Specifically, we propose (1) novel contrasting strategies that leverage structural similarity across volumetric medical images (domain-specific cue) and (2) a local version of the contrastive loss to learn distinctive representations of local regions that are useful for per-pixel segmentation (problem-specific cue). We carry out an extensive evaluation on three Magnetic Resonance Imaging (MRI) datasets. In the limited annotation setting, the proposed method yields substantial improvements compared to other self-supervision and semi-supervised learning techniques. When combined with a simple data augmentation technique, the proposed method reaches within 8% of benchmark performance using only two labeled MRI volumes for training, corresponding to only 4% (for ACDC) of the training data used to train the benchmark. The code is made public at https://github.com/krishnabits001/domain_specific_cl.


Improving GAN Training with Probability Ratio Clipping and Sample Reweighting

arXiv.org Machine Learning

Despite success on a wide range of problems related to vision, generative adversarial networks (GANs) often suffer from inferior performance due to unstable training, especially for text generation. To solve this issue, we propose a new variational GAN training framework which enjoys superior training stability. Our approach is inspired by a connection of GANs and reinforcement learning under a variational perspective. The connection leads to (1) probability ratio clipping that regularizes generator training to prevent excessively large updates, and (2) a sample re-weighting mechanism that improves discriminator training by downplaying bad-quality fake samples. Moreover, our variational GAN framework can provably overcome the training issue in many GANs that an optimal discriminator cannot provide any informative gradient to training generator. By plugging the training approach in diverse state-of-the-art GAN architectures, we obtain significantly improved performance over a range of tasks, including text generation, text style transfer, and image generation.


Continuous Lyapunov Controller and Chaotic Non-linear System Optimization using Deep Machine Learning

arXiv.org Artificial Intelligence

The introduction of unexpected system disturbances and new system dynamics does not allow initially selected static system and controller parameters to guarantee continued system stability and performance. In this research we present a novel approach for detecting early failure indicators of non-linear highly chaotic system and accordingly predict the best parameter calibrations to offset such instability using deep machine learning regression model. The approach proposed continuously monitors the system and controller signals. The Re-calibration of the system and controller parameters is triggered according to a set of conditions designed to maintain system stability without compromise to the system speed, intended outcome or required processing power. The deep neural model predicts the parameter values that would best counteract the expected system in-stability. To demonstrate the effectiveness of the proposed approach, it is applied to the non-linear complex combination of Duffing Van der pol oscillators. The approach is also tested under different scenarios the system and controller parameters are initially chosen incorrectly or the system parameters are changed while running or new system dynamics are introduced while running to measure effectiveness and reaction time.


Automatic Chronic Degenerative Diseases Identification Using Enteric Nervous System Images

arXiv.org Artificial Intelligence

Studies recently accomplished on the Enteric Nervous System have shown that chronic degenerative diseases affect the Enteric Glial Cells (EGC) and, thus, the development of recognition methods able to identify whether or not the EGC are affected by these type of diseases may be helpful in its diagnoses. In this work, we propose the use of pattern recognition and machine learning techniques to evaluate if a given animal EGC image was obtained from a healthy individual or one affect by a chronic degenerative disease. In the proposed approach, we have performed the classification task with handcrafted features and deep learning based techniques, also known as non-handcrafted features. The handcrafted features were obtained from the textural content of the ECG images using texture descriptors, such as the Local Binary Pattern (LBP). Moreover, the representation learning techniques employed in the approach are based on different Convolutional Neural Network (CNN) architectures, such as AlexNet and VGG16, with and without transfer learning. The complementarity between the handcrafted and non-handcrafted features was also evaluated with late fusion techniques. The datasets of EGC images used in the experiments, which are also contributions of this paper, are composed of three different chronic degenerative diseases: Cancer, Diabetes Mellitus, and Rheumatoid Arthritis. The experimental results, supported by statistical analysis, shown that the proposed approach can distinguish healthy cells from the sick ones with a recognition rate of 89.30% (Rheumatoid Arthritis), 98.45% (Cancer), and 95.13% (Diabetes Mellitus), being achieved by combining classifiers obtained both feature scenarios.


Resource-Aware Pareto-Optimal Automated Machine Learning Platform

arXiv.org Artificial Intelligence

In this study, we introduce a novel platform Resource-Aware AutoML (RA-AutoML) which enables flexible and generalized algorithms to build machine learning models subjected to multiple objectives, as well as resource and hard-ware constraints. RA-AutoML intelligently conducts Hyper-Parameter Search(HPS) as well as Neural Architecture Search (NAS) to build models optimizing predefined objectives. RA-AutoML is a versatile framework that allows user to prescribe many resource/hardware constraints along with objectives demanded by the problem at hand or business requirements. At its core, RA-AutoML relies on our in-house search-engine algorithm,MOBOGA, which combines a modified constraint-aware Bayesian Optimization and Genetic Algorithm to construct Pareto optimal candidates. Our experiments on CIFAR-10 dataset shows very good accuracy compared to results obtained by state-of-art neural network models, while subjected to resource constraints in the form of model size.


A Sui Generis QA Approach using RoBERTa for Adverse Drug Event Identification

arXiv.org Artificial Intelligence

Hence, researchers have started Extraction of adverse drug events from biomedical literature moving towards more automated approaches in machine and other textual data is an important component to learning. There has been a gradual shift towards using natural monitor drug-safety and this has attracted attention of many language processing (NLP) based methods. Early attempts researchers in healthcare. Existing works are more pivoted have incorporated the use of resources like NLM's MetaMap, around entity-relation extraction using bidirectional long Unified Medical Language System (UMLS) etc. [24] to extract short term memory networks (Bi-LSTM) which does not drugs for ADE identification tasks. However, a major limitation attain the best feature representations. In this paper, we introduce of these approaches is that they are not able to capture a question answering framework that exploits the the causal relationships between drug and ADE properly.


DeepWay: a Deep Learning Estimator for Unmanned Ground Vehicle Global Path Planning

arXiv.org Artificial Intelligence

Abstract--Agriculture 3.0 and 4.0 have gradually introduced Successively, output waypoints are processed with a I. Finally, the global path is computed through Over the past years, several research activities related to the A* search algorithm. Extensive experimentation with the precision agriculture and smart farming have been published synthetic dataset and real satellite-derived images of different [1]-[5], sign of a new industrial revolution approaching the scenarios are used to validate the proposed methodology. Agriculture 4.0 brought a new concept of of our training and testing code and data are open source and agriculture based on the introduction of robotics, artificial publicly available Section 2 in order to increase production efficiency and to cut labour covers the synthetic dataset design and generation. In this regard, self-driving agricultural machinery plays 3, the proposed methodology is analyzed with a detailed a relevant role both in production efficiency, by providing explanation of the DeepWay architecture and the waypoint a 24/7 weather-independent working production system, and refinement and path generation processes. Finally, section 4 cost-cutting, since there is not the need of a paid driver presents the experimental results and discussion followed by when performing the required task anymore.


Knowledge Graph Embedding with Atrous Convolution and Residual Learning

arXiv.org Artificial Intelligence

Knowledge graph embedding is an important task and it will benefit lots of downstream applications. Currently, deep neural networks based methods achieve state-of-the-art performance. However, most of these existing methods are very complex and need much time for training and inference. To address this issue, we propose a simple but effective atrous convolution based knowledge graph embedding method. Compared with existing state-of-the-art methods, our method has following main characteristics. First, it effectively increases feature interactions by using atrous convolutions. Second, to address the original information forgotten issue and vanishing/exploding gradient issue, it uses the residual learning method. Third, it has simpler structure but much higher parameter efficiency. We evaluate our method on six benchmark datasets with different evaluation metrics. Extensive experiments show that our model is very effective. On these diverse datasets, it achieves better results than the compared state-of-the-art methods on most of evaluation metrics. The source codes of our model could be found at https://github.com/neukg/AcrE.


Self-Imitation Learning in Sparse Reward Settings

arXiv.org Artificial Intelligence

The application of reinforcement learning (RL) in real-world is still limited in the environments with sparse and delayed rewards. Self-imitation learning (SIL) is developed as an auxiliary component of RL to relieve the problem by encouraging the agents to imitate their historical best behaviors. In this paper, we propose a practical SIL algorithm named Self-Imitation Learning with Constant Reward (SILCR). Instead of requiring hand-defined immediate rewards from environments, our algorithm assigns the immediate rewards at each timestep with constant values according to their final episodic rewards. In this way, even if the dense rewards from environments are unavailable, every action taken by the agents would be guided properly. We demonstrate the effectiveness of our method in some challenging MuJoCo locomotion tasks and the results show that our method significantly outperforms the alternative methods in tasks with delayed and sparse rewards. Even compared with alternatives with dense rewards available, our method achieves competitive performance. The ablation experiments also show the stability and reproducibility of our method.


Improving seasonal forecast using probabilistic deep learning

#artificialintelligence

The path toward realizing the potential of seasonal forecasting and its socioeconomic benefits depends heavily on improving general circulation model based dynamical forecasting systems. To improve dynamical seasonal forecast, it is crucial to set up forecast benchmarks, and clarify forecast limitations posed by model initialization errors, formulation deficiencies, and internal climate variability. With huge cost in generating large forecast ensembles, and limited observations for forecast verification, the seasonal forecast benchmarking and diagnosing task proves challenging. In this study, we develop a probabilistic deep neural network model, drawing on a wealth of existing climate simulations to enhance seasonal forecast capability and forecast diagnosis. By leveraging complex physical relationships encoded in climate simulations, our probabilistic forecast model demonstrates favorable deterministic and probabilistic skill compared to state-of-the-art dynamical forecast systems in quasi-global seasonal forecast of precipitation and near-surface temperature.