[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
Next Issue
Volume 4, March
Previous Issue
Volume 3, September
You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.
 
 

Mach. Learn. Knowl. Extr., Volume 3, Issue 4 (December 2021) – 14 articles

Cover Story (view full-size image): The rapid growth of research in explainable artificial intelligence (XAI) follows two substantial developments. First, the enormous application success of modern machine learning methods has created high expectations of industrial, commercial, and social value. Second, there is growing concern for creating ethical and trusted AI systems. As some surveys of current XAI suggest, a principled framework that respects the literature of explainability in the history of science and provides a basis for the development of a framework for transparent XAI is yet to be developed. In this paper, we identify four foundational components, and intend to synthesize ideas that can guide the design of AI systems that require XAI.View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
25 pages, 1242 KiB  
Article
Automated Event Detection and Classification in Soccer: The Potential of Using Multiple Modalities
by Olav Andre Nergård Rongved, Markus Stige, Steven Alexander Hicks, Vajira Lasantha Thambawita, Cise Midoglu, Evi Zouganeli, Dag Johansen, Michael Alexander Riegler and Pål Halvorsen
Mach. Learn. Knowl. Extr. 2021, 3(4), 1030-1054; https://doi.org/10.3390/make3040051 - 16 Dec 2021
Cited by 21 | Viewed by 6381
Abstract
Detecting events in videos is a complex task, and many different approaches, aimed at a large variety of use-cases, have been proposed in the literature. Most approaches, however, are unimodal and only consider the visual information in the videos. This paper presents and [...] Read more.
Detecting events in videos is a complex task, and many different approaches, aimed at a large variety of use-cases, have been proposed in the literature. Most approaches, however, are unimodal and only consider the visual information in the videos. This paper presents and evaluates different approaches based on neural networks where we combine visual features with audio features to detect (spot) and classify events in soccer videos. We employ model fusion to combine different modalities such as video and audio, and test these combinations against different state-of-the-art models on the SoccerNet dataset. The results show that a multimodal approach is beneficial. We also analyze how the tolerance for delays in classification and spotting time, and the tolerance for prediction accuracy, influence the results. Our experiments show that using multiple modalities improves event detection performance for certain types of events. Full article
(This article belongs to the Topic Applied Computer Vision and Pattern Recognition)
Show Figures

Figure 1

Figure 1
<p>Sample frames from the SoccerNet dataset [<a href="#B1-make-03-00051" class="html-bibr">1</a>] for three different event types. The middle frame is at the annotated time for the event.</p>
Full article ">Figure 2
<p>Illustration of the pipeline used by the video-based 3D-ResNet model.</p>
Full article ">Figure 3
<p>Illustration of the pipeline used by the video-based 2D-CNN model. A pre-trained ResNet is used to extract features from video, followed by PCA [<a href="#B1-make-03-00051" class="html-bibr">1</a>]. The features can then be used to train a network for action detection tasks.</p>
Full article ">Figure 4
<p>Detailed workflow for the 2D-CNN model. This model uses a pre-computed set of features and is tested with both visual and audio-visual (visual augmented with audio) features in our study.</p>
Full article ">Figure 5
<p>Illustration of the pipeline used by the audio-based model. First, audio is extracted from the video. The audio is used to compute Log-Mel spectrograms, which are then used as inputs to a 2D-ResNet.</p>
Full article ">Figure 6
<p><span class="html-italic">Early fusion.</span> Illustration of how audio-visual features can be created. A ResNet is used to compute visual features based on single frames. For the audio, a Log-Mel spectrogram is used to train a 2D-ResNet and further used as a feature extractor by removing the output layer. These features are then concatenated.</p>
Full article ">Figure 7
<p><span class="html-italic">Late fusion.</span> Visualization of how two seperate models can be fused through softmax average: a visual pathway that uses a feature extractor with a 2D-CNN, and an audio pathway that uses Log-Mel spectrograms with a 2D-ResNet. These models are trained individually, and the output predictions are fused by softmax (average or max).</p>
Full article ">Figure 8
<p>Classification performance with respect to window size (2–32), using the audio model and the ResNet visual features on the validation and test sets. In general, larger windows lead to better results.</p>
Full article ">Figure 9
<p>Illustration of window positions relative to the event, for a given sample. A centered window uses both past and future information, while a backward or forward (shifted) window relies only on the past and future, respectively.</p>
Full article ">Figure 10
<p>Classification performance in terms of F1 score, for the 2D (<a href="#sec3dot3-make-03-00051" class="html-sec">Section 3.3</a>) and the 3D (<a href="#sec3dot2-make-03-00051" class="html-sec">Section 3.2</a>) models using different input types. We present the results for selected samples from <a href="#make-03-00051-t006" class="html-table">Table 6</a> and <a href="#make-03-00051-t007" class="html-table">Table 7</a>, using window sizes of 8 and 16. The results for the combined input types are obtained using softmax average. We observe that for the <span class="html-italic">Goal</span> class, the multimodal approach always performs better.</p>
Full article ">Figure 11
<p>Spotting performance in terms of Average Precision per event type, for the CALF-60-5 and CALF-60-20 models over the tolerances 5, 20, and 60. In general, we can observe that for goals, adding audio information almost always improves performance. For other events, it depends on the configuration, but it seems like the more audio information is included, the better the results get.</p>
Full article ">
21 pages, 5730 KiB  
Article
Detection and Classification of Knee Injuries from MR Images Using the MRNet Dataset with Progressively Operating Deep Learning Methods
by Ali Can Kara and Fırat Hardalaç
Mach. Learn. Knowl. Extr. 2021, 3(4), 1009-1029; https://doi.org/10.3390/make3040050 - 16 Dec 2021
Cited by 14 | Viewed by 8817
Abstract
This study aimed to build progressively operating deep learning models that could detect meniscus injuries, anterior cruciate ligament (ACL) tears and knee abnormalities in magnetic resonance imaging (MRI). The Stanford Machine Learning Group MRNet dataset was employed in the study, which included MRI [...] Read more.
This study aimed to build progressively operating deep learning models that could detect meniscus injuries, anterior cruciate ligament (ACL) tears and knee abnormalities in magnetic resonance imaging (MRI). The Stanford Machine Learning Group MRNet dataset was employed in the study, which included MRI image indexes in the coronal, sagittal, and axial axes, each having 1130 trains and 120 validation items. The study is divided into three sections. In the first section, suitable images are selected to determine the disease in the image index based on the disturbance under examination. It is also used to identify images that have been misclassified or are noisy and/or damaged to the degree that they cannot be utilised for diagnosis in the first section. The study employed the 50-layer residual networks (ResNet50) model in this section. The second part of the study involves locating the region to be focused on based on the disturbance that is targeted to be diagnosed in the image under examination. A novel model was built by integrating the convolutional neural networks (CNN) and the denoising autoencoder models in the second section. The third section is dedicated to making a diagnosis of the disease. In this section, a novel ResNet50 model is trained to identify disease diagnoses or abnormalities, independent of the ResNet50 model used in the first section. The images that each model selects as output after training are referred to as progressively operating deep learning methods since they are supplied as an input to the following model. Full article
(This article belongs to the Section Learning)
Show Figures

Figure 1

Figure 1
<p>(<b>a</b>) Sagittal plane; (<b>b</b>) coronal plane; (<b>c</b>) axial plane [<a href="#B16-make-03-00050" class="html-bibr">16</a>].</p>
Full article ">Figure 2
<p>The function used to increase the number of channels and, an example of a 256 × 256 × 1 coronal image, which was converted to 256 × 256 × 3.</p>
Full article ">Figure 3
<p>General structure of image classification model.</p>
Full article ">Figure 4
<p>(<b>a</b>) Classification process of sagittal MRI; (<b>b</b>) confusion matrix of the produced validation dataset for sagittal plane; (<b>c</b>) training and validation accuracy rates; (<b>d</b>) training and validation loss values.</p>
Full article ">Figure 5
<p>Examples of unselected images and patients’ numbers in the dataset: (<b>a</b>) 0003; (<b>b</b>) 0370; (<b>c</b>) 0544; (<b>d</b>) 0582; (<b>e</b>) 0665; (<b>f</b>) 0776; (<b>g</b>) 1159; (<b>h</b>) 1230.</p>
Full article ">Figure 6
<p>(<b>a</b>) Classification process of coronal MRI; (<b>b</b>) confusion matrix of the produced validation dataset for coronal plane; (<b>c</b>) training and validation accuracy rates; (<b>d</b>) training and validation loss values.</p>
Full article ">Figure 7
<p>Examples of unselected images and patients’ numbers in the dataset; (<b>a</b>) 0310; (<b>b</b>) 0544; (<b>c</b>) 0610; (<b>d</b>) 0665; (<b>e</b>) 0975; (<b>f</b>) 1010; (<b>g</b>) 1043.</p>
Full article ">Figure 8
<p>(<b>a</b>) Classification process of axial MRI; (<b>b</b>) confusion matrix of the produced validation dataset for axial plane; (<b>c</b>) training and validation accuracy rates; (<b>d</b>) training and validation loss values.</p>
Full article ">Figure 9
<p>Examples of unselected images and patients’ numbers in the dataset: (<b>a</b>) 0577; (<b>b</b>) 0665; (<b>c</b>) 1136.</p>
Full article ">Figure 10
<p>(<b>a</b>) The red square indicates the area selected for ACL diagnosis; (<b>b</b>) the blue square indicates the area selected for meniscus diagnosis.</p>
Full article ">Figure 11
<p>The red rectangle is the area to be selected for ACL, while the blue rectangle is the area to be selected for meniscus. The green area shows the total area that we marked for diagnosis on the coronal plane.</p>
Full article ">Figure 12
<p>(<b>a</b>) The red square indicates the area selected for ACL diagnosis; (<b>b</b>) the blue square indicates the area selected for meniscus diagnosis.</p>
Full article ">Figure 13
<p>General structure of region of interest model.</p>
Full article ">Figure 14
<p>General structure of diagnosis model.</p>
Full article ">Figure 15
<p>General structure of progressively operating model.</p>
Full article ">
19 pages, 4788 KiB  
Article
AI-Based Video Clipping of Soccer Events
by Joakim Olav Valand, Haris Kadragic, Steven Alexander Hicks, Vajira Lasantha Thambawita, Cise Midoglu, Tomas Kupka, Dag Johansen, Michael Alexander Riegler and Pål Halvorsen
Mach. Learn. Knowl. Extr. 2021, 3(4), 990-1008; https://doi.org/10.3390/make3040049 - 8 Dec 2021
Cited by 8 | Viewed by 6428
Abstract
The current gold standard for extracting highlight clips from soccer games is the use of manual annotations and clippings, where human operators define the start and end of an event and trim away the unwanted scenes. This is a tedious, time-consuming, and expensive [...] Read more.
The current gold standard for extracting highlight clips from soccer games is the use of manual annotations and clippings, where human operators define the start and end of an event and trim away the unwanted scenes. This is a tedious, time-consuming, and expensive task, to the extent of being rendered infeasible for use in lower league games. In this paper, we aim to automate the process of highlight generation using logo transition detection, scene boundary detection, and optional scene removal. We experiment with various approaches, using different neural network architectures on different datasets, and present two models that automatically find the appropriate time interval for extracting goal events. These models are evaluated both quantitatively and qualitatively, and the results show that we can detect logo and scene transitions with high accuracy and generate highlight clips that are highly acceptable for viewers. We conclude that there is considerable potential in automating the overall soccer video clipping process. Full article
(This article belongs to the Topic Applied Computer Vision and Pattern Recognition)
Show Figures

Figure 1

Figure 1
<p>Tagging center in live operation. Several persons involved and a large number of buttons to press in a cumbersome, error-prone, and tedious manual process, affecting costs and quality. (<b>a</b>) One person can follow multiple games. (<b>b</b>) Adding metadata and fine-granular clipping.</p>
Full article ">Figure 2
<p>Example of original frame sequence and the clipping solutions.</p>
Full article ">Figure 3
<p>Typical logo transitions from the Norwegian Eliteserien dataset.</p>
Full article ">Figure 4
<p>The predicted false positive scene changes, where there are close similarities to abrupt and fade transitions.</p>
Full article ">Figure 5
<p>Some of the transitions the model misses.</p>
Full article ">Figure 6
<p>An overview of our final pipeline, over an example frame sequence where the time of the event is given as input. Frames where a cutting operation would be appropriate are found using SBD and logo transition detection, and the overall clipping protocol is described in Algorithm 1.</p>
Full article ">Figure 7
<p>Subjective evaluation: preferred model per question for different participant classes. Note that two clips are compared per question. The bar legend is shown in the bottom right plot. (<b>a</b>) Overall (61 persons). (<b>b</b>) Video editing experience (17 persons). (<b>c</b>) Soccer fans (30 persons). (<b>d</b>) Not soccer fans (31 persons). (<b>e</b>) Sport fans (47 persons). (<b>f</b>) Not sport fans (14 persons). (<b>g</b>) Females (15 persons). (<b>h</b>) Males (46 persons). (<b>i</b>) Age 29 and below (52 persons). (<b>j</b>) Age 30 and above (9 persons).</p>
Full article ">Figure 8
<p>Overfitting analysis: comparing training and validation loss (low is better) and accuracy (high is better). (<b>a</b>) Accuracy: Simple CNN. (<b>b</b>) Loss: Simple CNN. (<b>c</b>) Accuracy: ResNet. (<b>d</b>) Loss: ResNet.</p>
Full article ">
24 pages, 14468 KiB  
Perspective
Analysis of Explainers of Black Box Deep Neural Networks for Computer Vision: A Survey
by Vanessa Buhrmester, David Münch and Michael Arens
Mach. Learn. Knowl. Extr. 2021, 3(4), 966-989; https://doi.org/10.3390/make3040048 - 8 Dec 2021
Cited by 193 | Viewed by 13375
Abstract
Deep Learning is a state-of-the-art technique to make inference on extensive or complex data. As a black box model due to their multilayer nonlinear structure, Deep Neural Networks are often criticized as being non-transparent and their predictions not traceable by humans. Furthermore, the [...] Read more.
Deep Learning is a state-of-the-art technique to make inference on extensive or complex data. As a black box model due to their multilayer nonlinear structure, Deep Neural Networks are often criticized as being non-transparent and their predictions not traceable by humans. Furthermore, the models learn from artificially generated datasets, which often do not reflect reality. By basing decision-making algorithms on Deep Neural Networks, prejudice and unfairness may be promoted unknowingly due to a lack of transparency. Hence, several so-called explanators, or explainers, have been developed. Explainers try to give insight into the inner structure of machine learning black boxes by analyzing the connection between the input and output. In this survey, we present the mechanisms and properties of explaining systems for Deep Neural Networks for Computer Vision tasks. We give a comprehensive overview about the taxonomy of related studies and compare several survey papers that deal with explainability in general. We work out the drawbacks and gaps and summarize further research ideas. Full article
(This article belongs to the Section Thematic Reviews)
Show Figures

Figure 1

Figure 1
<p>DeepFool [<a href="#B8-make-03-00048" class="html-bibr">8</a>] examines the robustness of neural networks. Very small noisy images were added on correctly classified images; humans cannot see the difference, but the model changes its prediction: <span class="html-italic">x</span> (<b>left</b>) is correctly classified as whale, but <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>+</mo> <mi>r</mi> </mrow> </semantics></math> as turtle; <span class="html-italic">r</span> (<b>right</b>) is very small.</p>
Full article ">Figure 2
<p>Reference [<a href="#B23-make-03-00048" class="html-bibr">23</a>] created artificial images that were unrecognizable by humans, but the state-of-the-art classifier was very confident that they were known objects. Images are either directly (<b>top</b>) or indirectly (<b>bottom</b>) encoded.</p>
Full article ">Figure 3
<p>Texture–shape cue conflict [<a href="#B24-make-03-00048" class="html-bibr">24</a>]: texture (<b>left</b>) is classified as elephant; content (<b>middle</b>) is classified as cat; texture–shape (<b>right</b>) is classified as elephant because of a texture bias.</p>
Full article ">Figure 4
<p>Reference [<a href="#B24-make-03-00048" class="html-bibr">24</a>] showed that Convolutional Neural Networks focus more on texture than on shapes and that it is a good idea to improve shape bias to obtain more reliable results in the way humans would interpret the content of an image.</p>
Full article ">Figure 5
<p><b>DeconvNet</b> [<a href="#B51-make-03-00048" class="html-bibr">51</a>]: three examples of the input image (<b>a</b>), strongest feature map (<b>b</b>), and feature map projections (<b>c</b>) of Layer 5 and the classifier with the probability of the correct class (<b>d</b>) and the most probable class (<b>e</b>), respectively.</p>
Full article ">Figure 6
<p>Reference [<a href="#B7-make-03-00048" class="html-bibr">7</a>] presented Local Interpretable Model-agnostic Explanations (LIMEs), which can explain the predictions of any agnostic black box classifier and any data. Here, the superpixels, which are areas of an input image, are highlighted that are most responsible for the top three image classification predictions: (<b>1</b>) original image, (<b>2</b>) explaining electric guitar, (<b>3</b>) explaining acoustic guitar, and (<b>4</b>) explaining Labrador.</p>
Full article ">Figure 7
<p>Layerwise Relevance Propagation (LRP) [<a href="#B53-make-03-00048" class="html-bibr">53</a>] is a gradient method suffering from the shattered gradients problem. The idea behind it is a decomposition of the prediction function as a sum of layerwise relevance values. When the LRP is applied to deep ReLU networks, the LRP can be understood as a deep Taylor decomposition of the prediction.</p>
Full article ">Figure 8
<p>Deep inside convolutional networks [<a href="#B59-make-03-00048" class="html-bibr">59</a>]: created input images that have the highest probability of being predicted as certain classes of a trained CNN. Here, one can see the created prototypes of the classes goose, ostrich, and limousine (<b>left</b> to <b>right</b>).</p>
Full article ">Figure 9
<p>To explain what a black box classifier network comprehends as a class member [<a href="#B58-make-03-00048" class="html-bibr">58</a>] to make synthetic prototype images that look real. They were created by a deep generator network and classified by the black box neural network.</p>
Full article ">Figure 10
<p>Gradient-weighted Class Activation Mapping (Grad-CAM) [<a href="#B86-make-03-00048" class="html-bibr">86</a>] explains the outcome decision of cat or dog, respectively, of an input image using the gradient information to understand the importance of each neuron in the last convolutional layer of the CNN.</p>
Full article ">Figure 11
<p>Deep Learning [<a href="#B88-make-03-00048" class="html-bibr">88</a>]: This method highlights the region of an image (dog) that is most important for the part “dog” of the not quite correct predicted output “A dog is standing on a hardwood floor” of a trained CNN. However, the dog is not standing.</p>
Full article ">Figure 12
<p>Deep visual explanation [<a href="#B90-make-03-00048" class="html-bibr">90</a>] highlights the most discriminative region in an image of six examples (park bench, cockatoo, street sign, traffic light, racket, chihuahua) to explain the decision made by VGG-16.</p>
Full article ">Figure 13
<p>Multimodal Explanation (<b>ME</b>) [<a href="#B97-make-03-00048" class="html-bibr">97</a>] explains by two types of justifications of visual question answering task: The example shows two images with food, and the question is if they contain healthy meals or not. The explanations of the answers “yes” or “no” are given textually in justifying in a sentence and visually in pointing out the most responsible areas of the image.</p>
Full article ">Figure 14
<p>Summit [<a href="#B98-make-03-00048" class="html-bibr">98</a>] visualizes what features a Deep-Learning model has learned and how those features are connected to make predictions. The Embedding View (<b>A</b>) shows which classes are related to each other; the Class Sidebar (<b>B</b>) is linked to the embedding view, listing all classes sorted in several ways; the Attribution Graph (<b>C</b>) summarizes crucial neuron associations and substructures that contribute to a model’s prediction.</p>
Full article ">Figure 15
<p>Activation atlases with 100,000 activations [<a href="#B63-make-03-00048" class="html-bibr">63</a>].</p>
Full article ">Figure 16
<p>Extremal perturbations [<a href="#B112-make-03-00048" class="html-bibr">112</a>]: The example shows the regions of an image (boxed) that maximally affect the activation of a certain neuron in a DNN (“mousetrap” class score). For clarity, the masked regions are blacked out. In practice, the network sees blurred regions.</p>
Full article ">
20 pages, 2264 KiB  
Article
A Novel Feature Representation for Prediction of Global Horizontal Irradiance Using a Bidirectional Model
by Sourav Malakar, Saptarsi Goswami, Bhaswati Ganguli, Amlan Chakrabarti, Sugata Sen Roy, K. Boopathi and A. G. Rangaraj
Mach. Learn. Knowl. Extr. 2021, 3(4), 946-965; https://doi.org/10.3390/make3040047 - 25 Nov 2021
Cited by 1 | Viewed by 3424
Abstract
Complex weather conditions—in particular clouds—leads to uncertainty in photovoltaic (PV) systems, which makes solar energy prediction very difficult. Currently, in the renewable energy domain, deep-learning-based sequence models have reported better results compared to state-of-the-art machine-learning models. There are quite a few choices of [...] Read more.
Complex weather conditions—in particular clouds—leads to uncertainty in photovoltaic (PV) systems, which makes solar energy prediction very difficult. Currently, in the renewable energy domain, deep-learning-based sequence models have reported better results compared to state-of-the-art machine-learning models. There are quite a few choices of deep-learning architectures, among which Bidirectional Gated Recurrent Unit (BGRU) has apparently not been used earlier in the solar energy domain. In this paper, BGRU was used with a new augmented and bidirectional feature representation. The used BGRU network is more generalized as it can handle unequal lengths of forward and backward context. The proposed model produced 59.21%, 37.47%, and 76.80% better prediction accuracy compared to traditional sequence-based, bidirectional models, and some of the established states-of-the-art models. The testbed considered for evaluation of the model is far more comprehensive and reliable considering the variability in the climatic zones and seasons, as compared to some of the recent studies in India. Full article
(This article belongs to the Special Issue Recent Advances in Feature Selection)
Show Figures

Figure 1

Figure 1
<p>A neural network based on GRU cells.</p>
Full article ">Figure 2
<p>A network of bidirectional GRU (<b>a</b>) contexts with similar lengths and (<b>b</b>) contexts with different length.</p>
Full article ">Figure 3
<p>Schematic diagram of (<b>a</b>) ULSTM (<b>b</b>) M-ULSTM (<b>c</b>) BLSTM (<b>d</b>) BD-BLSTM/BD-BGRU.</p>
Full article ">Figure 4
<p>Solar stations based on climatic zones.</p>
Full article ">Figure 5
<p>Variability in deviation of GHI (W/m<math display="inline"><semantics> <msup> <mrow/> <mn>2</mn> </msup> </semantics></math>) in the winter season.</p>
Full article ">Figure 5 Cont.
<p>Variability in deviation of GHI (W/m<math display="inline"><semantics> <msup> <mrow/> <mn>2</mn> </msup> </semantics></math>) in the winter season.</p>
Full article ">Figure 6
<p>Variability in deviation of GHI (W/m<math display="inline"><semantics> <msup> <mrow/> <mn>2</mn> </msup> </semantics></math>) in the rainy season.</p>
Full article ">Figure 6 Cont.
<p>Variability in deviation of GHI (W/m<math display="inline"><semantics> <msup> <mrow/> <mn>2</mn> </msup> </semantics></math>) in the rainy season.</p>
Full article ">Figure 7
<p>Season specific variability in predictions.</p>
Full article ">Figure 8
<p>Climatic-zone specific variability in predictions.</p>
Full article ">
24 pages, 789 KiB  
Article
Language Semantics Interpretation with an Interaction-Based Recurrent Neural Network
by Shaw-Hwa Lo and Yiqiao Yin
Mach. Learn. Knowl. Extr. 2021, 3(4), 922-945; https://doi.org/10.3390/make3040046 - 19 Nov 2021
Cited by 2 | Viewed by 3002
Abstract
Text classification is a fundamental language task in Natural Language Processing. A variety of sequential models are capable of making good predictions, yet there is a lack of connection between language semantics and prediction results. This paper proposes a novel influence score (I-score), [...] Read more.
Text classification is a fundamental language task in Natural Language Processing. A variety of sequential models are capable of making good predictions, yet there is a lack of connection between language semantics and prediction results. This paper proposes a novel influence score (I-score), a greedy search algorithm, called Backward Dropping Algorithm (BDA), and a novel feature engineering technique called the “dagger technique”. First, the paper proposes to use the novel influence score (I-score) to detect and search for the important language semantics in text documents that are useful for making good predictions in text classification tasks. Next, a greedy search algorithm, called the Backward Dropping Algorithm, is proposed to handle long-term dependencies in the dataset. Moreover, the paper proposes a novel engineering technique called the “dagger technique” that fully preserves the relationship between the explanatory variable and the response variable. The proposed techniques can be further generalized into any feed-forward Artificial Neural Networks (ANNs) and Convolutional Neural Networks (CNNs), and any neural network. A real-world application on the Internet Movie Database (IMDB) is used and the proposed methods are applied to improve prediction performance with an 81% error reduction compared to other popular peers if I-score and “dagger technique” are not implemented. Full article
(This article belongs to the Section Learning)
Show Figures

Figure 1

Figure 1
<p>Mechanism between I-score gain and AUC gain. This figure presents the mechanism of how the I-score can increase AUC. There are four plots. The top left plot is a ROC curve with one particular pair of (1-Specificity, Sensitivity). The top right plot presents sensitivity gain from the I-score. The bottom left plot presents specificity gain from the I-score. Both sensitivity and specificity are driving forces of the AUC values because they move the dot up or left, which then increases the area-under-curve (the blue area). The bottom right plot presents performance gain from both sensitivity and specificity. In summary, the implementation of using the proposed I-score can increase AUC by selecting the features raising both sensitivity (from part (i) of the I-score, see Equation (14)) and specificity (from part (ii) of the I-score, see Equation (14)).</p>
Full article ">Figure 2
<p>A Simple RNN for Text Classification. This diagram illustrates the basic steps of using RNN for text classification. The input features are <math display="inline"><semantics> <mrow> <mo>{</mo> <msub> <mi>X</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>X</mi> <mn>2</mn> </msub> <mo>,</mo> <mo>…</mo> <mo>}</mo> </mrow> </semantics></math>. The hidden neurons are <math display="inline"><semantics> <mrow> <mo>{</mo> <msub> <mi>h</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>h</mi> <mn>2</mn> </msub> <mo>,</mo> <mo>…</mo> <mo>}</mo> </mrow> </semantics></math>. The output prediction is <math display="inline"><semantics> <mover accent="true"> <mi>Y</mi> <mo stretchy="false">^</mo> </mover> </semantics></math>. Since this is the text classification problem, the architecture has many inputs and one output, hence the name “many-to-one”. The architecture has parameters <math display="inline"><semantics> <mrow> <mo>{</mo> <mi>U</mi> <mo>,</mo> <mi>V</mi> <mo>,</mo> <mi>W</mi> <mo>}</mo> </mrow> </semantics></math> and these weights (or parameters) are shareable throughout the architecture.</p>
Full article ">Figure 3
<p>Executive Diagram for the Proposed Method. This figure represents the proposed methodologies using N-grams, I-score, and the “dagger technique”. The forward propagation and the backward propagation remain the same before and after using I-score. The function <math display="inline"><semantics> <mrow> <mi mathvariant="sans-serif">Γ</mi> <mo>(</mo> <mo>·</mo> <mo>)</mo> </mrow> </semantics></math> acts as a gate to release the neuron according to certain I-score criteria. (<b>A</b>) Panel A presents the Recurrent Neural Network design to implement I-score at each step of the neural network architecture. (<b>B</b>) Panel B presents features constructed using the “dagger technique” and then fed into the Recurrent Neural Network (RNNs) architecture.</p>
Full article ">Figure 4
<p>Learning Paths Before and After Discretization. This figure presents the training procedure. All graphs present the training and validating paths. The first graph is from the original bi-gram data. The second is from using discretized bi-gram (discretized by I-score). The third is using the top 18 variables according to I-score values. The proposed method can significantly improve the computation efficiency.</p>
Full article ">Figure 5
<p>Learning Paths Before and After Text Reduction Using I-score. This figure presents the training procedure. All graphs present the training and validating paths. The first graph is from the original bi-gram data. The second is from using discretized bi-gram (discretized by I-score). The third is using the top 18 variables according to I-score values. The proposed method can significantly improve the computation efficiency.</p>
Full article ">
22 pages, 923 KiB  
Article
A Multi-Component Framework for the Analysis and Design of Explainable Artificial Intelligence
by Mi-Young Kim, Shahin Atakishiyev, Housam Khalifa Bashier Babiker, Nawshad Farruque, Randy Goebel, Osmar R. Zaïane, Mohammad-Hossein Motallebi, Juliano Rabelo, Talat Syed, Hengshuai Yao and Peter Chun
Mach. Learn. Knowl. Extr. 2021, 3(4), 900-921; https://doi.org/10.3390/make3040045 - 18 Nov 2021
Cited by 29 | Viewed by 6880
Abstract
The rapid growth of research in explainable artificial intelligence (XAI) follows on two substantial developments. First, the enormous application success of modern machine learning methods, especially deep and reinforcement learning, have created high expectations for industrial, commercial, and social value. Second, the emerging [...] Read more.
The rapid growth of research in explainable artificial intelligence (XAI) follows on two substantial developments. First, the enormous application success of modern machine learning methods, especially deep and reinforcement learning, have created high expectations for industrial, commercial, and social value. Second, the emerging and growing concern for creating ethical and trusted AI systems, including compliance with regulatory principles to ensure transparency and trust. These two threads have created a kind of “perfect storm” of research activity, all motivated to create and deliver any set of tools and techniques to address the XAI demand. As some surveys of current XAI suggest, there is yet to appear a principled framework that respects the literature of explainability in the history of science and which provides a basis for the development of a framework for transparent XAI. We identify four foundational components, including the requirements for (1) explicit explanation knowledge representation, (2) delivery of alternative explanations, (3) adjusting explanations based on knowledge of the explainee, and (4) exploiting the advantage of interactive explanation. With those four components in mind, we intend to provide a strategic inventory of XAI requirements, demonstrate their connection to a basic history of XAI ideas, and then synthesize those ideas into a simple framework that can guide the design of AI systems that require XAI. Full article
(This article belongs to the Special Issue Advances in Explainable Artificial Intelligence (XAI))
Show Figures

Figure 1

Figure 1
<p>Interpretability of a model vs. explainability of a prediction.</p>
Full article ">Figure 2
<p>The process steps of the reasoning methods.</p>
Full article ">Figure 3
<p>Major explanatory components (stacked bar) and their potential role in a scale of explanation.</p>
Full article ">
21 pages, 9680 KiB  
Article
Deep Self-Organizing Map of Convolutional Layers for Clustering and Visualizing Image Data
by Christos Ferles, Yannis Papanikolaou, Stylianos P. Savaidis and Stelios A. Mitilineos
Mach. Learn. Knowl. Extr. 2021, 3(4), 879-899; https://doi.org/10.3390/make3040044 - 14 Nov 2021
Cited by 4 | Viewed by 6045
Abstract
The self-organizing convolutional map (SOCOM) hybridizes convolutional neural networks, self-organizing maps, and gradient backpropagation optimization into a novel integrated unsupervised deep learning model. SOCOM structurally combines, architecturally stacks, and algorithmically fuses its deep/unsupervised learning components. The higher-level representations produced by its underlying convolutional [...] Read more.
The self-organizing convolutional map (SOCOM) hybridizes convolutional neural networks, self-organizing maps, and gradient backpropagation optimization into a novel integrated unsupervised deep learning model. SOCOM structurally combines, architecturally stacks, and algorithmically fuses its deep/unsupervised learning components. The higher-level representations produced by its underlying convolutional deep architecture are embedded in its topologically ordered neural map output. The ensuing unsupervised clustering and visualization operations reflect the model’s degree of synergy between its building blocks and synopsize its range of applications. Clustering results are reported on the STL-10 benchmark dataset coupled with the devised neural map visualizations. The series of conducted experiments utilize a deep VGG-based SOCOM model. Full article
(This article belongs to the Section Visualization)
Show Figures

Figure 1

Figure 1
<p>Detailed architecture of a SOCOM paradigm consisting of an input layer (green), 3 convolutional layers (yellow) followed by ReLUs (blue), 2 pooling layers (red), 3 fully connected layers (turquoise), and an output neural map (purple).</p>
Full article ">Figure 2
<p>Example of a convolutional layer comprised of 2 filters (yellow) that are applied to a 3 channel input volume. Subsequently, each element of the resulting feature maps is fed through a ReLU (blue).</p>
Full article ">Figure 3
<p>Example of a pooling layer (red) connected after a convolutional or ReLU layer comprised of 5 feature maps.</p>
Full article ">Figure 4
<p>Example of 2 successive fully connected layers (turquoise) following a convolutional-ReLU or pooling layer (red).</p>
Full article ">Figure 5
<p>Example of an output layer consisting of neurons arranged onto an orthogonal lattice (purple). For performing the designed projection, each individual neuron receives the activations from units of the last fully connected layer (turquoise).</p>
Full article ">Figure 6
<p>Neural map visualization (NMV) of the 8 × 6 neural output map of a SOCOM trained on the STL-10 benchmark dataset. Each individual neuron of the grid is represented by a synthetic image that depicts what the neuron models and which are the representations/patterns maximizing its response. As can be seen, there is a one-to-one correspondence between the individual cluster/neuron visualizations and the respective categories obtained after posterior labeling of each neuron by applying the majority voting scheme. With respect to the topographical arrangement of the neural output map this posterior labeling is the following.</p>
Full article ">Figure 7
<p>Upper row: selected synthetic images (taken from the overall NMV) of SOCOM neurons representing monkeys, airplanes, and cats. Lower row: the analogous synthetic images of the output units of the vgg11 classifier that represent the exact same categories of data. As can be seen, without being identical, they focus on the same characteristics and patterns of the input data (edges, parts of the head, vertices at different scales, and orientations) to achieve the respective clustering and classification results, despite the fact that the underlying mechanisms of their output layers are different.</p>
Full article ">Figure 8
<p>The best-matching images, from the STL-10 testing batch, of every neuron forming the 8 × 6 SOCOM neural map. Each individual neuron is represented by the four images yielding the highest activations among all the images assigned to the specific neuron. If a neuron describes/contains less than four images (or even no images at all) this is shown by empty/white slots.</p>
Full article ">Figure 9
<p>Training evolution of two characteristic types of SOCOMs, alongside the trajectories of the respective performance criteria. (<b>Left</b>) The networks’ error/loss values across training time (i.e., epochs). (<b>Right</b>) The achieved accuracies at each stage of the unsupervised learning procedure.</p>
Full article ">
16 pages, 759 KiB  
Review
Recent Advances in Deep Reinforcement Learning Applications for Solving Partially Observable Markov Decision Processes (POMDP) Problems Part 2—Applications in Transportation, Industries, Communications and Networking and More Topics
by Xuanchen Xiang, Simon Foo and Huanyu Zang
Mach. Learn. Knowl. Extr. 2021, 3(4), 863-878; https://doi.org/10.3390/make3040043 - 28 Oct 2021
Cited by 5 | Viewed by 6336
Abstract
The two-part series of papers provides a survey on recent advances in Deep Reinforcement Learning (DRL) for solving partially observable Markov decision processes (POMDP) problems. Reinforcement Learning (RL) is an approach to simulate the human’s natural learning process, whose key is to let [...] Read more.
The two-part series of papers provides a survey on recent advances in Deep Reinforcement Learning (DRL) for solving partially observable Markov decision processes (POMDP) problems. Reinforcement Learning (RL) is an approach to simulate the human’s natural learning process, whose key is to let the agent learn by interacting with the stochastic environment. The fact that the agent has limited access to the information of the environment enables AI to be applied efficiently in most fields that require self-learning. It’s essential to have an organized investigation—we can make good comparisons and choose the best structures or algorithms when applying DRL in various applications. The first part of the overview introduces Markov Decision Processes (MDP) problems and Reinforcement Learning and applications of DRL for solving POMDP problems in games, robotics, and natural language processing. In part two, we continue to introduce applications in transportation, industries, communications and networking, etc. and discuss the limitations of DRL. Full article
(This article belongs to the Section Thematic Reviews)
Show Figures

Figure 1

Figure 1
<p>Two popular types of state representation in an intersection with four roads (in four different colors) and three lanes in each road: (<b>a</b>) DTSE matrix—Each cell represents one vehicle; (<b>b</b>) Feature-based state vector – Each cell represents a lane [<a href="#B2-make-03-00043" class="html-bibr">2</a>].</p>
Full article ">Figure 2
<p>The schematic diagram of smart grid using DRL [<a href="#B67-make-03-00043" class="html-bibr">67</a>].</p>
Full article ">Figure 3
<p>General RL/DRL model for autonomous IoT [<a href="#B71-make-03-00043" class="html-bibr">71</a>].</p>
Full article ">Figure 4
<p>The outline of applications of RL in healthcare [<a href="#B100-make-03-00043" class="html-bibr">100</a>].</p>
Full article ">
28 pages, 8130 KiB  
Review
A Review of the Role of Machine Learning Techniques towards Brain–Computer Interface Applications
by Saim Rasheed
Mach. Learn. Knowl. Extr. 2021, 3(4), 835-862; https://doi.org/10.3390/make3040042 - 26 Oct 2021
Cited by 36 | Viewed by 7020
Abstract
This review article provides a deep insight into the Brain–Computer Interface (BCI) and the application of Machine Learning (ML) technology in BCIs. It investigates the various types of research undertaken in this realm and discusses the role played by ML in performing different [...] Read more.
This review article provides a deep insight into the Brain–Computer Interface (BCI) and the application of Machine Learning (ML) technology in BCIs. It investigates the various types of research undertaken in this realm and discusses the role played by ML in performing different BCI tasks. It also reviews the ML methods used for mental state detection, mental task categorization, emotion classification, electroencephalogram (EEG) signal classification, event-related potential (ERP) signal classification, motor imagery categorization, and limb movement classification. This work explores the various methods employed in BCI mechanisms for feature extraction, selection, and classification and provides a comparative study of reviewed methods. This paper assists the readers to gain information regarding the developments made in BCI and ML domains and future improvements needed for improving and designing better BCI applications. Full article
(This article belongs to the Section Thematic Reviews)
Show Figures

Figure 1

Figure 1
<p>Standard BCI system.</p>
Full article ">Figure 2
<p>WPD process.</p>
Full article ">Figure 3
<p>DWT process.</p>
Full article ">Figure 4
<p>Publication year analysis.</p>
Full article ">
16 pages, 879 KiB  
Article
Fully Homomorphically Encrypted Deep Learning as a Service
by George Onoufriou, Paul Mayfield and Georgios Leontidis
Mach. Learn. Knowl. Extr. 2021, 3(4), 819-834; https://doi.org/10.3390/make3040041 - 13 Oct 2021
Cited by 11 | Viewed by 4207
Abstract
Fully Homomorphic Encryption (FHE) is a relatively recent advancement in the field of privacy-preserving technologies. FHE allows for the arbitrary depth computation of both addition and multiplication, and thus the application of abelian/polynomial equations, like those found in deep learning algorithms. This project [...] Read more.
Fully Homomorphic Encryption (FHE) is a relatively recent advancement in the field of privacy-preserving technologies. FHE allows for the arbitrary depth computation of both addition and multiplication, and thus the application of abelian/polynomial equations, like those found in deep learning algorithms. This project investigates how FHE with deep learning can be used at scale toward accurate sequence prediction, with a relatively low time complexity, the problems that such a system incurs, and mitigations/solutions for such problems. In addition, we discuss how this could have an impact on the future of data privacy and how it can enable data sharing across various actors in the agri-food supply chain, hence allowing the development of machine learning-based systems. Finally, we find that although FHE incurs a high spatial complexity cost, the run time is within expected reasonable bounds, while allowing for absolutely private predictions to be made, in our case for milk yield prediction with a Mean Absolute Percentage Error (MAPE) of 12.4% and an accuracy of 87.6% on average. Full article
(This article belongs to the Section Privacy)
Show Figures

Figure 1

Figure 1
<p>The pipeline demonstrates the key stages of our project, from the client and raw data (<b>upper left</b>) to the data processing and analytics (<b>lower right</b>).</p>
Full article ">Figure 2
<p>Serialised representation of encrypted data using CKKS scheme, and including all private, relin, and public keys, where objects here are byte arrays.</p>
Full article ">Figure 3
<p>FHE dashboard, allowing simple upload, data view (of metadata since data is encrypted), and processing of data.</p>
Full article ">Figure 4
<p>FHE compatible neural network graph implemented by Python-ReSeal [<a href="#B22-make-03-00041" class="html-bibr">22</a>], visualised using PyVis, deployed towards predicting time series milk yield data via 1D Convolutional Neural Network (CNN)/biased cross-correlation (CC) with activation. Further in this diagram, blue represents input nodes, yellow represents CC/CNN nodes/components, pink represents the dense layer to condense the feature vector from the CNN layer, green is all glue operations such as enqueue and dequeue to merge and split inputs along varying edges respectively, orange is predictions, and red is loss functions. Purple is a special/unique set of operations related to the encryption itself such as decryption before moving on to the final circuit.</p>
Full article ">Figure 5
<p>Graphical comparison of the sigmoid (purple) and sigmoid approximation (green) functions, showing their similarity between the range of −5 and 5.</p>
Full article ">
17 pages, 2351 KiB  
Article
Knowledge Graphs Representation for Event-Related E-News Articles
by M.V.P.T. Lakshika and H.A. Caldera
Mach. Learn. Knowl. Extr. 2021, 3(4), 802-818; https://doi.org/10.3390/make3040040 - 26 Sep 2021
Cited by 5 | Viewed by 4962
Abstract
E-newspaper readers are overloaded with massive texts on e-news articles, and they usually mislead the reader who reads and understands information. Thus, there is an urgent need for a technology that can automatically represent the gist of these e-news articles more quickly. Currently, [...] Read more.
E-newspaper readers are overloaded with massive texts on e-news articles, and they usually mislead the reader who reads and understands information. Thus, there is an urgent need for a technology that can automatically represent the gist of these e-news articles more quickly. Currently, popular machine learning approaches have greatly improved presentation accuracy compared to traditional methods, but they cannot be accommodated with the contextual information to acquire higher-level abstraction. Recent research efforts in knowledge representation using graph approaches are neither user-driven nor flexible to deviations in the data. Thus, there is a striking concentration on constructing knowledge graphs by combining the background information related to the subjects in text documents. We propose an enhanced representation of a scalable knowledge graph by automatically extracting the information from the corpus of e-news articles and determine whether a knowledge graph can be used as an efficient application in analyzing and generating knowledge representation from the extracted e-news corpus. This knowledge graph consists of a knowledge base built using triples that automatically produce knowledge representation from e-news articles. Inclusively, it has been observed that the proposed knowledge graph generates a comprehensive and precise knowledge representation for the corpus of e-news articles. Full article
(This article belongs to the Section Visualization)
Show Figures

Figure 1

Figure 1
<p>The KG construction pipeline.</p>
Full article ">Figure 2
<p>Tags generated by NLP technique, Part of Speech (POS) tagging.</p>
Full article ">Figure 3
<p>Identified entities after applying Named Entity Recognition (NER).</p>
Full article ">Figure 4
<p>Obtained outputs from open information extraction (OpenIE) using the Stanford CoreNLP libraries.</p>
Full article ">Figure 5
<p>Obtained output from co-reference resolution using the Stanford CoreNLP libraries.</p>
Full article ">Figure 6
<p>Constituency parse tree, which breaks a sentence into sub -phrases.</p>
Full article ">Figure 7
<p>Dependency parse tree, which analyzes the grammatical construction of a sentence.</p>
Full article ">Figure 8
<p>A portion of sample KG generated by our pipeline.</p>
Full article ">Figure 9
<p>Representation of hierarchical relations using Hearst patterns.</p>
Full article ">Figure 10
<p>E-news article—length distribution.</p>
Full article ">Figure 11
<p>Named Entity type distribution.</p>
Full article ">Figure 12
<p>Triple distribution in KB.</p>
Full article ">
14 pages, 1106 KiB  
Article
An Assessment of the Application of Private Aggregation of Ensemble Models to Sensible Data
by Sergio Yovine, Franz Mayr, Sebastián Sosa and Ramiro Visca
Mach. Learn. Knowl. Extr. 2021, 3(4), 788-801; https://doi.org/10.3390/make3040039 - 25 Sep 2021
Cited by 1 | Viewed by 3558
Abstract
This paper explores the use of Private Aggregation of Teacher Ensembles (PATE) in a setting where students have their own private data that cannot be revealed as is to the ensemble. We propose a privacy model that introduces a local differentially private mechanism [...] Read more.
This paper explores the use of Private Aggregation of Teacher Ensembles (PATE) in a setting where students have their own private data that cannot be revealed as is to the ensemble. We propose a privacy model that introduces a local differentially private mechanism to protect student data. We implemented and analyzed it in case studies from security and health domains, and the result of the experiment was twofold. First, this model does not significantly affecs predictive capabilities, and second, it unveiled interesting issues with the so-called data dependency privacy loss metric, namely, high variance and values. Full article
(This article belongs to the Section Privacy)
Show Figures

Figure 1

Figure 1
<p>Context without privacy.</p>
Full article ">Figure 2
<p>Local model.</p>
Full article ">Figure 3
<p>Centralized model.</p>
Full article ">Figure 4
<p>Private Aggregation of Teacher Ensembles (PATE).</p>
Full article ">Figure 5
<p>Graph of <math display="inline"><semantics> <mrow> <mn>2</mn> <mi>T</mi> <msup> <mi>γ</mi> <mn>2</mn> </msup> <mi>λ</mi> <mrow> <mo>(</mo> <mi>λ</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>−</mo> <mo form="prefix">log</mo> <mi>δ</mi> </mrow> </semantics></math>. Data independent epsilon is <math display="inline"><semantics> <mrow> <msubsup> <mi>ε</mi> <mi mathvariant="italic">ind</mi> <mo>*</mo> </msubsup> <mo>≃</mo> <mn>20.1743</mn> </mrow> </semantics></math> at <math display="inline"><semantics> <mrow> <mi>λ</mi> <mo>≃</mo> <mn>1.51743</mn> </mrow> </semantics></math>.</p>
Full article ">Figure 6
<p>PATE with protected student data.</p>
Full article ">Figure 7
<p>Neural network architecture used for teachers and student in the ECG example.</p>
Full article ">Figure 8
<p>Ensemble accuracy evaluated on student data by privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in ECG dataset.</p>
Full article ">Figure 9
<p>PATE accuracy evaluated on student data by privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in ECG dataset.</p>
Full article ">Figure 10
<p>Validation accuracy by student privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in ECG dataset.</p>
Full article ">Figure 11
<p>Privacy loss by student privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in ECG dataset.</p>
Full article ">Figure 12
<p>Neural network architecture used for teachers and student in Web Request example.</p>
Full article ">Figure 13
<p>Validation TPR by student privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in Web Requests dataset.</p>
Full article ">Figure 14
<p>Validation TNR by student privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in Web Requests dataset.</p>
Full article ">Figure 15
<p>Privacy loss by student privacy parameter <math display="inline"><semantics> <mi>ρ</mi> </semantics></math> in Web Requests dataset.</p>
Full article ">
17 pages, 1044 KiB  
Article
A Critical Study on Stability Measures of Feature Selection with a Novel Extension of Lustgarten Index
by Rikta Sen, Ashis Kumar Mandal and Basabi Chakraborty
Mach. Learn. Knowl. Extr. 2021, 3(4), 771-787; https://doi.org/10.3390/make3040038 - 24 Sep 2021
Cited by 2 | Viewed by 3427
Abstract
Stability of feature selection algorithm refers to its robustness to the perturbations of the training set, parameter settings or initialization. A stable feature selection algorithm is crucial for identifying the relevant feature subset of meaningful and interpretable features which is extremely important in [...] Read more.
Stability of feature selection algorithm refers to its robustness to the perturbations of the training set, parameter settings or initialization. A stable feature selection algorithm is crucial for identifying the relevant feature subset of meaningful and interpretable features which is extremely important in the task of knowledge discovery. Though there are many stability measures reported in the literature for evaluating the stability of feature selection, none of them follows all the requisite properties of a stability measure. Among them, the Kuncheva index and its modifications, are widely used in practical problems. In this work, the merits and limitations of the Kuncheva index and its existing modifications (Lustgarten, Wald, nPOG/nPOGR, Nogueira) are studied and analysed with respect to the requisite properties of stability measure. One more limitation of the most recent modified similarity measure, Nogueira’s measure, has been pointed out. Finally, corrections to Lustgarten’s measure have been proposed to define a new modified stability measure that satisfies the desired properties and overcomes the limitations of existing popular similarity based stability measures. The effectiveness of the newly modified Lustgarten’s measure has been evaluated with simple toy experiments. Full article
(This article belongs to the Special Issue Recent Advances in Feature Selection)
Show Figures

Figure 1

Figure 1
<p>Similarity measures for the case when <math display="inline"><semantics> <mrow> <msub> <mi>S</mi> <mi>i</mi> </msub> <mo>⊂</mo> <msub> <mi>S</mi> <mi>j</mi> </msub> </mrow> </semantics></math> or vice versa.</p>
Full article ">Figure 2
<p>Similarity values when two feature subsets are identical.</p>
Full article ">Figure 3
<p>Similarity values when the intersection of the feature subsets is null.</p>
Full article ">
Previous Issue
Next Issue
Back to TopTop