The recognition of emotions is one of the most challenging issues in human–computer interaction (HCI). EEG signals are widely adopted as a method for recognizing emotions because of their ease of acquisition, mobility, and convenience. Deep neural networks (DNN) have provided excellent results in emotion recognition studies. Most studies, however, use other methods to extract handcrafted features, such as Pearson correlation coefficient (PCC), Principal Component Analysis, Higuchi Fractal Dimension (HFD), etc., even though DNN is capable of generating meaningful features. Furthermore, most earlier studies largely ignored spatial information between the different channels, focusing mainly on time domain and frequency domain representations. This study utilizes a pre-trained 3D-CNN MobileNet model with transfer learning on the spatio-temporal representation of EEG signals to extract features for emotion recognition. In addition to fully connected layers, hybrid models were explored using other decision layers such as multilayer perceptron (MLP), k-nearest neighbor (KNN), extreme learning machine (ELM), XGBoost (XGB), random forest (RF), and support vector machine (SVM). Additionally, this study investigates the effects of post-processing or filtering output labels. Extensive experiments were conducted on the SJTU Emotion EEG Dataset (SEED) (three classes) and SEED-IV (four classes) datasets, and the results obtained were comparable to the state-of-the-art. Based on the conventional 3D-CNN with ELM classifier, SEED and SEED-IV datasets showed a maximum accuracy of 89.18% and 81.60%, respectively. Post-filtering improved the emotional classification performance in the hybrid 3D-CNN with ELM model for SEED and SEED-IV datasets to 90.85% and 83.71%, respectively. Accordingly, spatial-temporal features extracted from the EEG, along with ensemble classifiers, were found to be the most effective in recognizing emotions compared to state-of-the-art methods.

Non‐invasive methods accomplished by a computer aided diagnosis of knee‐joint disorders provide an effective tool. The objective of this study is to analyse vibroarthographic (VAG) signals using non‐linear signal processing technique. This study includes different entropy‐based feature extraction techniques to attain highly distinguishable features. The authors proposed to use a non‐linear method known as complete ensemble empirical mode decomposition with adaptive white noise to decompose the VAG signals into intrinsic mode functions (IMFs). Entropy‐based features involving approximate entropy, sample entropy, Shannon entropy, Rényi entropy, Tsallis entropy and permutation entropy (PeEn) are computed from dominant IMFs and reconstructed VAG signals. These extracted features are given as input to the least squares support vector machine as a classifier. The results illustrated that PeEn performed better with respect to other entropies. PeEn gives a classification accuracy of 86.61% and Matthews correlation coefficient of 0.7082. The computational complexity of entropies was also analysed. Results inferred that PeEn has a computational complexity of O ( N ) provided a simple, robust and low computational feature extraction technique. Analysis of VAG signals using non‐linear preprocessing and entropy‐based features can provide highly distinguishable features for accurate detection of knee‐joint disorders.

Affective computing is an emerging area of education research and has the potential to enhance educational outcomes. Despite the growing number of literature studies, there are still deficiencies and gaps in the domain of affective computing in education. In this study, we systematically review affective computing in the education domain. Methods: We queried four well-known research databases, namely the Web of Science Core Collection, IEEE Xplore, ACM Digital Library, and PubMed, using specific keywords for papers published between January 2010 and July 2023. Various relevant data items are extracted and classified based on a set of 15 extensive research questions. Following the PRISMA 2020 guidelines, a total of 175 studies were selected and reviewed in this work from among 3102 articles screened. The data show an increasing trend in publications within this domain. The most common research purpose involves designing emotion recognition/expression systems. Conventional textual questionnaires remain the most popular channels for affective measurement. Classrooms are identified as the primary research environments; the largest research sample group is university students. Learning domains are mainly associated with science, technology, engineering, and mathematics (STEM) courses. The bibliometric analysis reveals that most publications are affiliated with the USA. The studies are primarily published in journals, with the majority appearing in the Frontiers in Psychology journal. Research gaps, challenges, and potential directions for future research are explored. This review synthesizes current knowledge regarding the application of affective computing in the education sector. This knowledge is useful for future directions to help educational researchers, policymakers, and practitioners deploy affective computing technology to broaden educational practices.

Leather is a durable material well-known for its fashion, style, and versatility. Identifying the animal species from which leather originated is necessary in leather quality-check, fraud detection, exotic animal protection, etc. The species identification techniques currently in practice involve subjective and supervised analysis with laboratory-specific devices. This paper discusses optimized and automated species identification by employing a portable and cost-effective (economically efficient) digital microscope. The goal is to acquire the leather images of the four most predominantly used permissible species, with the definite hair-pore regions. Preliminary experiments investigate the adequate image sensing parameters for efficient sensor data processing. Otsu’s thresholding followed by circular Hough transform (CHT) segments and estimates the morphological features of the informative hair-pore regions. The k-nearest neighbor (KNN) based machine learning algorithm models a pattern recognition technique for automated species prediction. Evaluation measures objectively validate the performance of the proposed pre-processing and hair-pore segmentation. The experimental analysis presents the uniqueness and significance of estimated morphological features. The study also compares KNN and Multi-Layer Perceptron (MLP) based species prediction. The comparative analysis ascertains the significance of KNN-based leather species identification with 92.5% accuracy. Thus, the present research assists in building the digital signatures of permissible leather species. It also contributes to design a cost-effective and automated leather species prediction technique with objective analysis.