Cognitive radio (CR)-based Internet of Things (IoT) system is an effective step toward a world of smart technology. Many frameworks have been proposed to build CR-based IoT systems. The CR-based IoT frameworks are the key points on which this survey focuses. Efficient spectrum sensing and sharing are the main functional components of the CR-based IoT. Reviews of recent SS and sharing approaches are presented in this survey. This survey classifies the SS and sharing approaches and discusses the merits and limitations of those approaches. Moreover, this survey discusses the design factors of the CR-based IoT and the criteria by which the proper SS and access approaches are selected. Furthermore, the survey explores the integration of newly emerging technologies with the CR-based IoT systems. Finally, the survey highlights some emerging challenges and concludes with suggesting future research directions and open issues.

Diabetic Retinopathy is one of the leading global causes of vision impairment and blindness in humans. It has seen a rise in prevalence, necessitating the development of advanced automatic detection methods. This paper presents a survey of the evolution in deep learning techniques for diabetic retinopathy detection, emphasizing the transition from traditional machine learning to sophisticated deep learning architectures such as convolutional neural networks. It discusses the role of transfer learning, end-to-end learning, and hybrid models in overcoming medical detection challenges while highlighting the need for artificial intelligence interpretability and real-time screening integration in clinical workflows. Building on this survey, the paper introduces a focused study on cross-dataset deployment of transfer learning for diabetic retinopathy detection and grading. Consequently, this paper evaluates 26 pre-trained models from various convolutional neural network families to provide a comprehensive comparison between the state-of-the-art CNN architectures in the field. Additionally, this study also employs Grad-CAM visualization to interpret the model’s decision-making, bridging advanced artificial intelligence techniques with practical healthcare applications for diabetic retinopathy.

Voice disability is a barrier of effective communication. Around 1.2% of the World’s population are facing some form of voice disability. Surgical procedures namely laryngoscopy, laryngeal electromyography, and stroboscopy are used for voice disability diagnosis. Researchers and practitioners have been working to find alternatives to these surgical procedures. Voice sample based diagnosis is one of them. The major steps followed by these works are (a) to extract voice features from voice samples and (b) to discriminate pathological voices from normal voices by using classifier algorithm. However, there is no consensus about the voice feature and classifier algorithm that can provide the best accuracy in screening voice disability. Moreover, some of the works use multiple voice features and multiple classifiers to ensure high reliability. In this paper, we address these issues. The motivation of the work is to address the need for non invasive signal processing technique to detect voice disability in general population. A comprehensive survey work is done related to voice disability detection methods. The paper contains two main parts. In the first part, we present background information including causes of voice disability, current procedures and practices, voice features, and classifiers. In the second part, we present a comprehensive survey work on voice disability detection algorithms. The issues and challenges related to the selection of voice feature and classifier algorithms have been addressed at the end of this paper.

This article presents two new approaches of fetal electrocardiogram (ECG) signal (FECG) separation using the input-mode adaptive filter (IMAF) and the output-mode adaptive filter (OMAF). Both approaches use the recursive least-squares (RLS) and the least-mean-squares (LMS) algorithms and a single-reference-generation block. In the IMAF, the filter’s primary input is connected directly to the abdominal signal. The reference signal is generated by windowing the abdominal signal according to the locations of the QRS MECG pulses. In the OMAF, the filter’s primary input is connected to the output stage of a blind source separation block. The reference signal is generated by windowing the raw FECG signal, from the BSS output, according to the locations of the QRS pulses of the extracted MECG signal. We selected the null space idempotent transformation matrix (NSITM) as the BSS algorithm used in this work. Results from real Daisy and Physionet databases show the successful extraction of the FECG signal. Results from synthesized data from Physionet databases, using OMAF, show considerable improvement in extraction performances over NSITM and IMAF when the fetal-to-maternal signal-to-noise ratio (fmSNR) increases from −30 to 0 dB. This study demonstrated that the OMAF is a feasible algorithm for FECG extraction.

Heartbeats are important aspects for the study of heart diseases in medical sciences as they provide vital information on heart disorders and abnormalities in heart rhythms. Each heartbeat provides a QRS complex in the electrocardiogram (ECG) which is centered at the R-peak. The analysis of ECG is hindered by low-frequency noise, high-frequency noise, interference from P and T waves, and changes in QRS morphology. This paper presents a new peak detection algorithm that can suppress the noise and adapt to changes in ECG signal morphology for better detection performance. The proposed algorithm is based on median and moving average (MA) filtering, segmentation, time and amplitude thresholds, and statistical false peak elimination (SFPE). The filters are first used in preprocessing to reduce unwanted noise and interference. The data is then divided into smaller segments and each segment is then analyzed using two distinct thresholds, a time axis (x-axis) threshold and an amplitude (y-axis) threshold. Next, the false peaks are eliminated resulting from any residue of noise using an average value of peak-to-peak interval. A post-processing stage is added to eliminate any peak that is detected twice and to search for missed low-amplitude peaks. The proposed method is tested on MIT-BIH arrhythmia and Fantasia databases and provides better results in comparison to several state-of-the-art methods in the field. The mean sensitivity, positive predictivity, and detection error rates for the proposed method are 99.82%, 99.88%, and 0.31%, respectively, for the MIT-BIH arrhythmia database and 99.92%, 99.90%, and 0.18%, respectively, for the Fantasia database.

This paper presents a pathological voice identification system employing signal processing techniques through cochlear implant models. The fundamentals of the biological process for speech perception are investigated to develop this technique. Two cochlear implant models are considered in this work: one uses a conventional bank of bandpass filters, and the other one uses a bank of optimized gammatone filters. The critical center frequencies of those filters are selected to mimic the human cochlear vibration patterns caused by audio signals. The proposed system processes the speech samples and applies a CNN for final pathological voice identification. The results show that the two proposed models adopting bandpass and gammatone filterbanks can discriminate the pathological voices from healthy ones, resulting in F1 scores of 77.6% and 78.7%, respectively, with speech samples. The obtained results of this work are also compared with those of other related published works.