2,562 research outputs found
Explainable cardiac pathology classification on cine MRI with motion characterization by semi-supervised learning of apparent flow
We propose a method to classify cardiac pathology based on a novel approach
to extract image derived features to characterize the shape and motion of the
heart. An original semi-supervised learning procedure, which makes efficient
use of a large amount of non-segmented images and a small amount of images
segmented manually by experts, is developed to generate pixel-wise apparent
flow between two time points of a 2D+t cine MRI image sequence. Combining the
apparent flow maps and cardiac segmentation masks, we obtain a local apparent
flow corresponding to the 2D motion of myocardium and ventricular cavities.
This leads to the generation of time series of the radius and thickness of
myocardial segments to represent cardiac motion. These time series of motion
features are reliable and explainable characteristics of pathological cardiac
motion. Furthermore, they are combined with shape-related features to classify
cardiac pathologies. Using only nine feature values as input, we propose an
explainable, simple and flexible model for pathology classification. On ACDC
training set and testing set, the model achieves 95% and 94% respectively as
classification accuracy. Its performance is hence comparable to that of the
state-of-the-art. Comparison with various other models is performed to outline
some advantages of our model
Feature construction using explanations of individual predictions
Feature construction can contribute to comprehensibility and performance of
machine learning models. Unfortunately, it usually requires exhaustive search
in the attribute space or time-consuming human involvement to generate
meaningful features. We propose a novel heuristic approach for reducing the
search space based on aggregation of instance-based explanations of predictive
models. The proposed Explainable Feature Construction (EFC) methodology
identifies groups of co-occurring attributes exposed by popular explanation
methods, such as IME and SHAP. We empirically show that reducing the search to
these groups significantly reduces the time of feature construction using
logical, relational, Cartesian, numerical, and threshold num-of-N and X-of-N
constructive operators. An analysis on 10 transparent synthetic datasets shows
that EFC effectively identifies informative groups of attributes and constructs
relevant features. Using 30 real-world classification datasets, we show
significant improvements in classification accuracy for several classifiers and
demonstrate the feasibility of the proposed feature construction even for large
datasets. Finally, EFC generated interpretable features on a real-world problem
from the financial industry, which were confirmed by a domain expert.Comment: 54 pages, 10 figures, 22 table
Classification of Explainable Artificial Intelligence Methods through Their Output Formats
Machine and deep learning have proven their utility to generate data-driven models with high accuracy and precision. However, their non-linear, complex structures are often difficult to interpret. Consequently, many scholars have developed a plethora of methods to explain their functioning and the logic of their inferences. This systematic review aimed to organise these methods into a hierarchical classification system that builds upon and extends existing taxonomies by adding a significant dimensionâthe output formats. The reviewed scientific papers were retrieved by conducting an initial search on Google Scholar with the keywords âexplainable artificial intelligenceâ; âexplainable machine learningâ; and âinterpretable machine learningâ. A subsequent iterative search was carried out by checking the bibliography of these articles. The addition of the dimension of the explanation format makes the proposed classification system a practical tool for scholars, supporting them to select the most suitable type of explanation format for the problem at hand. Given the wide variety of challenges faced by researchers, the existing XAI methods provide several solutions to meet the requirements that differ considerably between the users, problems and application fields of artificial intelligence (AI). The task of identifying the most appropriate explanation can be daunting, thus the need for a classification system that helps with the selection of methods. This work concludes by critically identifying the limitations of the formats of explanations and by providing recommendations and possible future research directions on how to build a more generally applicable XAI method. Future work should be flexible enough to meet the many requirements posed by the widespread use of AI in several fields, and the new regulation
Machine Learning for Fluid Mechanics
The field of fluid mechanics is rapidly advancing, driven by unprecedented
volumes of data from field measurements, experiments and large-scale
simulations at multiple spatiotemporal scales. Machine learning offers a wealth
of techniques to extract information from data that could be translated into
knowledge about the underlying fluid mechanics. Moreover, machine learning
algorithms can augment domain knowledge and automate tasks related to flow
control and optimization. This article presents an overview of past history,
current developments, and emerging opportunities of machine learning for fluid
mechanics. It outlines fundamental machine learning methodologies and discusses
their uses for understanding, modeling, optimizing, and controlling fluid
flows. The strengths and limitations of these methods are addressed from the
perspective of scientific inquiry that considers data as an inherent part of
modeling, experimentation, and simulation. Machine learning provides a powerful
information processing framework that can enrich, and possibly even transform,
current lines of fluid mechanics research and industrial applications.Comment: To appear in the Annual Reviews of Fluid Mechanics, 202
Personalized multi-task attention for multimodal mental health detection and explanation
The unprecedented spread of smartphone usage and its various boarding sensors have been garnering increasing interest in automatic mental health detection. However, there are two major barriers to reliable mental health detection applications that can be adopted in real-life: (a)The outputs of the complex machine learning model are not explainable, which reduces the trust of users and thus hinders the application in real-life scenarios. (b)The sensor signal distribution discrepancy across individuals is a major barrier to accurate detection since each individual has their own characteristics. We propose an explainable mental health detection model. Spatial and temporal features of multiple sensory sequences are extracted and fused with different weights generated by the attention mechanism so that the discrepancy of contribution to classifiers across different modalities can be considered in the model. Through a series of experiments on real-life datasets, results show the effectiveness of our model compared to the existing approaches.This research is supported by the National Natural Science Foundation of China (No. 62077027), the Ministry of Science and Technology of the People's Republic of China(No. 2018YFC2002500), the Jilin Province Development and Reform Commission, China (No. 2019C053-1), the Education Department of Jilin Province, China (No. JJKH20200993K), the Department of Science and Technology of Jilin Province, China (No. 20200801002GH), and the European Union's Horizon 2020 FET Proactive project "WeNet-The Internet of us"(No. 823783)
On explaining machine learning models by evolving crucial and compact features
Feature construction can substantially improve the accuracy of Machine Learning (ML) algorithms. Genetic Programming (GP) has been proven to be effective at this task by evolving non-linear combinations of input features. GP additionally has the potential to improve ML explainability since explicit expressions are evolved. Yet, in most GP works the complexity of evolved features is not explicitly bound or minimized though this is arguably key for explainability. In this article, we assess to what extent GP still performs favorably at feature construction when constructing features that are (1) Of small-enough number, to enable visualization of the behavior of the ML model; (2) Of small-enough size, to enable interpretability of the features themselves; (3) Of sufficient informative power, to retain or even improve the performance of the ML algorithm. We consider a simple feature construction scheme using three different GP algorithms, as well as random search, to evolve features for five ML algorithms, including support vector machines and random forest. Our results on 21 datasets pertaining to classification and regression problems show that constructing only two compact features can be sufficient to rival the use of the entire original feature set. We further find that a modern GP algorithm, GP-GOMEA, performs best overall. These results, combined with examples that we provide of readable constructed features and of 2D visualizations of ML behavior, lead us to positively conclude that GP-based feature construction still works well when explicitly searching for compact features, making it extremely helpful to explain ML models
Explainable AI for tool wear prediction in turning
This research aims develop an Explainable Artificial Intelligence (XAI)
framework to facilitate human-understandable solutions for tool wear prediction
during turning. A random forest algorithm was used as the supervised Machine
Learning (ML) classifier for training and binary classification using
acceleration, acoustics, temperature, and spindle speed during the orthogonal
tube turning process as input features. The ML classifier was used to predict
the condition of the tool after the cutting process, which was determined in a
binary class form indicating if the cutting tool was available or failed. After
the training process, the Shapley criterion was used to explain the predictions
of the trained ML classifier. Specifically, the significance of each input
feature in the decision-making and classification was identified to explain the
reasoning of the ML classifier predictions. After implementing the Shapley
criterion on all testing datasets, the tool temperature was identified as the
most significant feature in determining the classification of available versus
failed cutting tools. Hence, this research demonstrates capability of XAI to
provide machining operators the ability to diagnose and understand complex ML
classifiers in prediction of tool wear
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