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Deep Metric Learning Model for Imbalanced Fault Diagnosis

arXiv.org Artificial Intelligence

Intelligent diagnosis method based on data-driven and deep learning is an attractive and meaningful field in recent years. However, in practical application scenarios, the imbalance of time-series fault is an urgent problem to be solved. This paper proposes a novel deep metric learning model, where imbalanced fault data and a quadruplet data pair design manner are considered. Based on such data pair, a quadruplet loss function which takes into account the inter-class distance and the intra-class data distribution are proposed. This quadruplet loss pays special attention to imbalanced sample pair. The reasonable combination of quadruplet loss and softmax loss function can reduce the impact of imbalance. Experiment results on two open-source datasets show that the proposed method can effectively and robustly improve the performance of imbalanced fault diagnosis.


Decision Tree Algorithms-Machine Learning

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Decision Tree Algorithm one of the easiest and popular Algorithms to predict the output. The Decision Tree Algorithm is a part of the supervised machine learning algorithm. Here the problem is represented in a form of a tree to predict the outcome. This algorithm aims to create a model that should predict the value of a variable that is targeted, and for this purpose, it is represented in a form of a decision tree. It is used for classification problems and also for regression problems.


Explainable AI (XAI) for PHM of Industrial Asset: A State-of-The-Art, PRISMA-Compliant Systematic Review

arXiv.org Artificial Intelligence

A state-of-the-art systematic review on XAI applied to Prognostic and Health Management (PHM) of industrial asset is presented. The work attempts to provide an overview of the general trend of XAI in PHM, answers the question of accuracy versus explainability, investigates the extent of human role, explainability evaluation and uncertainty management in PHM XAI. Research articles linked to PHM XAI, in English language, from 2015 to 2021 are selected from IEEE Xplore, ScienceDirect, SpringerLink, ACM Digital Library and Scopus databases using PRISMA guidelines. Data was extracted from 35 selected articles and examined using MS. Excel. Several findings were synthesized. Firstly, while the discipline is still young, the analysis indicates the growing acceptance of XAI in PHM domain. Secondly, XAI functions as a double edge sword, where it is assimilated as a tool to execute PHM tasks as well as a mean of explanation, in particular in diagnostic and anomaly detection. There is thus a need for XAI in PHM. Thirdly, the review shows that PHM XAI papers produce either good or excellent results in general, suggesting that PHM performance is unaffected by XAI. Fourthly, human role, explainability metrics and uncertainty management are areas requiring further attention by the PHM community. Adequate explainability metrics to cater for PHM need are urgently needed. Finally, most case study featured on the accepted articles are based on real, indicating that available AI and XAI approaches are equipped to solve complex real-world challenges, increasing the confidence of AI model adoption in the industry. This work is funded by the Universiti Teknologi Petronas Foundation.


Chest X-ray AI solution which detects 124 clinical findings launched

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The company was originally formed as a joint venture between Australian healthcare technology company Harrison.ai The launch of Annalise CXR coincides with its publication of a peer-reviewed diagnostic accuracy study published by The Lancet Digital Health, which is the largest of its kind ever undertaken in terms of the number of findings concurrently evaluated. The study found that when used as an assist device, Annalise CXR significantly improved the ability for radiologists to perceive 102 chest X-ray (CXR) findings in a non-clinical environment, was statistically non-inferior for 19 findings and no findings showed a decrease in accuracy. The study also assessed the standalone performance of the model in a non-clinical environment against radiologists in identifying chest x-ray pathology, as well as investigating the effect of model output on radiologist performance when used as an assist device. Annalise CXR's AI model classification alone was significantly more accurate than unassisted radiologists for 117 (94%) of 124 clinical findings predicted by the model and was non-inferior to unassisted radiologists for all other clinical findings.


The Hyperspherical Geometry of Community Detection: Modularity as a Distance

arXiv.org Machine Learning

The Louvain algorithm is currently one of the most popular community detection methods. This algorithm finds communities by maximizing a quantity called modularity. In this work, we describe a metric space of clusterings, where clusterings are described by a binary vector indexed by the vertex-pairs. We extend this geometry to a hypersphere and prove that maximizing modularity is equivalent to minimizing the angular distance to some modularity vector over the set of clustering vectors. This equivalence allows us to view the Louvain algorithm as a nearest-neighbor search that approximately minimizes the distance to this modularity vector. By replacing this modularity vector by a different vector, many alternative community detection methods can be obtained. We explore this wider class and compare it to existing modularity-based methods. Our experiments show that these alternatives may outperform modularity-based methods. For example, when communities are large compared to vertex neighborhoods, a vector based on numbers of common neighbors outperforms existing community detection methods. While the focus of the present work is community detection in networks, the proposed methodology can be applied to any clustering problem where pair-wise similarity data is available.


Synthetic COVID-19 Chest X-ray Dataset for Computer-Aided Diagnosis

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We introduce a new dataset called Synthetic COVID-19 Chest X-ray Dataset for training machine learning models. The dataset consists of 21,295 synthetic COVID-19 chest X-ray images to be used for computer-aided diagnosis. These images, generated via an unsupervised domain adaptation approach, are of high quality. We find that the synthetic images not only improve performance of various deep learning architectures when used as additional training data under heavy imbalance conditions, but also detect the target class with high confidence. We also find that comparable performance can also be achieved when trained only on synthetic images.


Labelling Drifts in a Fault Detection System for Wind Turbine Maintenance

arXiv.org Artificial Intelligence

A failure detection system is the first step towards predictive maintenance strategies. A popular data-driven method to detect incipient failures and anomalies is the training of normal behaviour models by applying a machine learning technique like feed-forward neural networks (FFNN) or extreme learning machines (ELM). However, the performance of any of these modelling techniques can be deteriorated by the unexpected rise of non-stationarities in the dynamic environment in which industrial assets operate. This unpredictable statistical change in the measured variable is known as concept drift. In this article a wind turbine maintenance case is presented, where non-stationarities of various kinds can happen unexpectedly. Such concept drift events are desired to be detected by means of statistical detectors and window-based approaches. However, in real complex systems, concept drifts are not as clear and evident as in artificially generated datasets. In order to evaluate the effectiveness of current drift detectors and also to design an appropriate novel technique for this specific industrial application, it is essential to dispose beforehand of a characterization of the existent drifts. Under the lack of information in this regard, a methodology for labelling concept drift events in the lifetime of wind turbines is proposed. This methodology will facilitate the creation of a drift database that will serve both as a training ground for concept drift detectors and as a valuable information to enhance the knowledge about maintenance of complex systems.


AMA-GCN: Adaptive Multi-layer Aggregation Graph Convolutional Network for Disease Prediction

arXiv.org Artificial Intelligence

Recently, Graph Convolutional Networks (GCNs) have proven to be a powerful mean for Computer Aided Diagnosis (CADx). This approach requires building a population graph to aggregate structural information, where the graph adjacency matrix represents the relationship between nodes. Until now, this adjacency matrix is usually defined manually based on phenotypic information. In this paper, we propose an encoder that automatically selects the appropriate phenotypic measures according to their spatial distribution, and uses the text similarity awareness mechanism to calculate the edge weights between nodes. The encoder can automatically construct the population graph using phenotypic measures which have a positive impact on the final results, and further realizes the fusion of multimodal information. In addition, a novel graph convolution network architecture using multi-layer aggregation mechanism is proposed. The structure can obtain deep structure information while suppressing over-smooth, and increase the similarity between the same type of nodes. Experimental results on two databases show that our method can significantly improve the diagnostic accuracy for Autism spectrum disorder and breast cancer, indicating its universality in leveraging multimodal data for disease prediction.


Next-Gen Machine Learning Supported Diagnostic Systems for Spacecraft

arXiv.org Artificial Intelligence

Future short or long-term space missions require a new generation of monitoring and diagnostic systems due to communication impasses as well as limitations in specialized crew and equipment. Machine learning supported diagnostic systems present a viable solution for medical and technical applications. We discuss challenges and applicability of such systems in light of upcoming missions and outline an example use case for a next-generation medical diagnostic system for future space operations. Additionally, we present approach recommendations and constraints for the successful generation and use of machine learning models aboard a spacecraft.


Handling Continuous Attributes in Decision Trees

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It can be seen that the computation of splitting measures assumes finite (read: discrete) attribute values. This begs the question, How are continuous-valued attributes handled in decision trees? The test condition for continuous-valued attributes can either be expressed using a comparison operator (,). Alternatively, the continuous-valued attribute can be split into a finite set of range buckets. It is important to note that a comparison-based test condition gives us a binary split whereas range buckets give us a multiway split.