An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

The Self-Organizing Map

To evaluate binary classifications and their confusion matrices, scientific researchers can employ several statistical rates, accordingly to the goal of the experiment they are investigating. Despite being a crucial issue in machine learning, no widespread consensus has been reached on a unified elective chosen measure yet. Accuracy and F1 score computed on confusion matrices have been (and still are) among the most popular adopted metrics in binary classification tasks. However, these statistical measures can dangerously show overoptimistic inflated results, especially on imbalanced datasets. The Matthews correlation coefficient (MCC), instead, is a more reliable statistical rate which produces a high score only if the prediction obtained good results in all of the four confusion matrix categories (true positives, false negatives, true negatives, and false positives), proportionally both to the size of positive elements and the size of negative elements in the dataset. In this article, we show how MCC produces a more informative and truthful score in evaluating binary classifications than accuracy and F1 score, by first explaining the mathematical properties, and then the asset of MCC in six synthetic use cases and in a real genomics scenario. We believe that the Matthews correlation coefficient should be preferred to accuracy and F1 score in evaluating binary classification tasks by all scientific communities.

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The advantages of the Matthews correlation coefficient (MCC) over F1 score and accuracy in binary classification evaluation

Classification assessment methods

There are two kinds of tutorial articles: those that provide a primer on an established topic and those that let us in on the ground floor of something of emerging importance. The first type of tutorial can have a noted expert who has been gracious (and brave) enough to write a field guide about a particular topic. The other sort of tutorial typically involves researchers who have each been laboring on a topic for some years. Both sorts of tutorial articles are very much desired. But we, as an editorial board for both Systems and Transactions, know that there has been no logical place for them in the AESS until this series was started several years ago. With these tutorials, we hope to continue to give them a home, a welcome, and provide a service to our membership. We do not intend to publish tutorials on a regular basis, but we hope to deliver them once or twice per year. We need and welcome good, useful tutorial articles (both kinds) in relevant AESS areas. If you, the reader, can offer a topic of interest and an author to write about it, please contact us. Self-nominations are welcome, and even more ideal is a suggestion of an article that the editor(s) can solicit. All articles will be reviewed in detail. Criteria on which they will be judged include their clarity of presentation, relevance, and likely audience, and, of course, their correctness and scientific merit. As to the mathematical level, the articles in this issue are a good guide: in each case the author has striven to explain complicated topics in simple-well, tutorial-terms. There should be no (or very little) novel material: the home for archival science is the Transactions Magazine, and submissions that need to be properly peer reviewed would be rerouted there. Likewise, articles that are interesting and descriptive, but lack significant tutorial content, ought more properly be submitted to the Systems Magazine.

What is a tutorial

Henry gas solubility optimization: A novel physics-based algorithm

Linear Discriminant Analysis (LDA) is a very common
technique for dimensionality reduction problems as a preprocessing
step for machine learning and pattern classification
applications. At the same time, it is usually used as a
black box, but (sometimes) not well understood. The aim of
this paper is to build a solid intuition for what is LDA, and
how LDA works, thus enabling readers of all levels be able
to get a better understanding of the LDA and to know how to
apply this technique in different applications. The paper first
gave the basic definitions and steps of how LDA technique
works supported with visual explanations of these steps.
Moreover, the two methods of computing the LDA space, i.e.
class-dependent and class-independent methods, were explained
in details. Then, in a step-by-step approach, two numerical
examples are demonstrated to show how the LDA
space can be calculated in case of the class-dependent and
class-independent methods. Furthermore, two of the most
common LDA problems (i.e. Small Sample Size (SSS) and
non-linearity problems) were highlighted and illustrated, and
state-of-the-art solutions to these problems were investigated and explained. Finally, a number of experiments was conducted
with different datasets to (1) investigate the effect of
the eigenvectors that used in the LDA space on the robustness
of the extracted feature for the classification accuracy,
and (2) to show when the SSS problem occurs and how it can
be addressed.

/pdf/linear-discriminant-analysis-a-detailed-tutorial-46ghcxadb9.pdf

Linear discriminant analysis: A detailed tutorial

The aim of this paper is to collect in one place the basic background needed to understand the discriminant analysis (DA) classifier to make the reader of all levels be able to get a better understanding of the DA and to know how to apply this classifier in different applications. This paper starts with basic mathematical definitions of the DA steps with visual explanations of these steps. Moreover, in a step-by-step approach, a number of numerical examples were illustrated to show how to calculate the discriminant functions and decision boundaries when the covariance matrices of all classes were common or not. The singularity problem of DA was explained and some of the state-of-the-art solutions to this problem were highlighted with numerical illustrations. An experiment is conducted to compare between the linear and quadratic classifiers and to show how to solve the singularity problem when high-dimensional datasets are used.

Linear vs. quadratic discriminant analysis classifier: a tutorial

Bezier Curve Based Path Planning in a Dynamic Field using Modified Genetic Algorithm

Path planning algorithms have been used in different applications with the aim of finding a suitable collision-free path which satisfies some certain criteria such as the shortest path length and smoothness; thus, defining a suitable curve to describe path is essential. The main goal of these algorithms is to find the shortest and smooth path between the starting and target points. This paper makes use of a Bezier curve-based model for path planning. The control points of the Bezier curve significantly influence the length and smoothness of the path. In this paper, a novel Chaotic Particle Swarm Optimization (CPSO) algorithm has been proposed to optimize the control points of Bezier curve, and the proposed algorithm comes in two variants: CPSO-I and CPSO-II. Using the chosen control points, the optimum smooth path that minimizes the total distance between the starting and ending points is selected. To evaluate the CPSO algorithm, the results of the CPSO-I and CPSO-II algorithms are compared with the standard PSO algorithm. The experimental results proved that the proposed algorithm is capable of finding the optimal path. Moreover, the CPSO algorithm was tested against different numbers of control points and obstacles, and the CPSO algorithm achieved competitive results.

Alaa Tharwat

Papers

Classification assessment methods

Linear discriminant analysis: A detailed tutorial

Linear vs. quadratic discriminant analysis classifier: a tutorial

Bezier Curve Based Path Planning in a Dynamic Field using Modified Genetic Algorithm

Intelligent Bézier curve-based path planning model using Chaotic Particle Swarm Optimization algorithm