In the last month of 2019, a new virus emerged in China, spreading rapidly and affecting the whole world. This virus, which is called corona, is the most contagious type of virus that humanity has ever encountered. The virus has caused a huge crisis worldwide as it leads to severe infections and eventually death in humans. On March 11, 2020, it was announced by the World Health Organization that a COVID-19 outbreak has occurred. Computer-aided digital technologies, which eliminate many problems and provide convenience in people's lives, did not leave humanity alone in this regard and rushed to provide a solution for this unfortunate event. One of the important aspects in which computer-aided digital technologies can be effective is the diagnosis of the disease. Reverse transcription-polymerase chain reaction (RT-PCR), which is a standard and precise technique for diagnosing the disease, is an expensive and time-consuming method. Moreover, its availability is not the same all over the world. For this reason, it can be very attractive and important to distinguish the COVID-19 disease from a cold or flu through a cough sound analysis via smartphones which have entered into the lives of many people in recent years. In this study, we proposed a machine learning-based system to distinguish patients with COVID-19 from non-COVID-19 patients by analyzing only a single cough sound. Two different data sets were used, one accessible for the public and the other available on request. After combining the data sets, the features were obtained from the cough sounds using the mel-frequency cepstral coefficients (MFCCs) method, and then, they were classified with seven different machine learning classifiers. To determine the optimum values of hyperparameters for MFCCs and classifiers, the leave-one-out cross-validation (LOO-CV) strategy was implemented. Based on the results, the k-nearest neighbors classifier based on the Euclidean distance (kNN Euclidean) with the accuracy rate, sensitivity of COVID-19, sensitivity of non-COVID-19, F-measure, and area under the ROC curve (AUC) of 0.9833, 1.0000, 0.9720, 0.9799, and 0.9860, respectively, is more successful than other classifiers. Finally, the best and most effective features were determined for each classifier using the sequential forward selection (SFS) method. According to the results, the proposed system is excellent compared with similar studies in the literature and can be easily used in smartphones and facilitate the diagnosis of COVID-19 patients. In addition, since the used data set includes reflex and unconscious coughs, the results showed that conscious or unconscious coughing has no effect on the diagnosis of COVID-19 patients based on the cough sound.Keywords Cough sound Á Classification Á Machine learning Á COVID-19 Á Coronavirus Á Computer-aided digital technologies This paper is dedicated to the memory of the late Dr. Mohsen MALEKI, who passed away from COVID-19 in November 2020.

Detailed In the brain-computer interface system (BCI), electroencephalography (EEG) signals are converted into digital signals and analyzed, allowing direct communication between humans and the electronic devices around them. The convenience of the user and the speed of communication with the surrounding devices are the most important challenges of BCI systems. The Emotiv Epoc headset minimizes the discomfort of the user thanks to its wet electrodes and easy handling. In the continuation of our previous works, in this paper, we developed our BCI system based on the gaze at the rotating vanes using the inexpensive Emotiv Epoc headset. In addition to user comfort, our design has an acceptable mean accuracy rate (ACC) and mean information transfer rate (ITR) compared to similar systems.

Different biological signals are recorded in sleep labs during sleep for the diagnosis and treatment of human sleep problems. Classification of sleep stages with electroencephalography (EEG) is preferred to other biological signals due to its advantages such as providing clinical information, cost-effectiveness, comfort, and ease of use. The evaluation of EEG signals taken during sleep by clinicians is a tiring, time-consuming, and error-prone method. Therefore, it is clinically mandatory to determine sleep stages by using software-supported systems. Like all classification problems, the accuracy rate is used to compare the performance of studies in this domain, but this metric can be accurate when the number of observations is equal in classes. However, since there is not an equal number of observations in sleep stages, this metric is insufficient in the evaluation of such systems. For this purpose, in recent years, Cohen's kappa coefficient and even the sensitivity of NREM1 have been used for comparing the performance of these systems. Still, none of them examine the system from all dimensions. Therefore, in this study, two new metrics based on the polygon area metric, called the normalized area of sensitivity polygon and normalized area of the general polygon, are proposed for the performance evaluation of sleep staging systems. In addition, a new sleep staging system is introduced using the applications offered by the MATLAB program. The existing systems discussed in the literature were examined with the proposed metrics, and the best systems were compared with the proposed sleep staging system. According to the results, the proposed system excels in comparison with the most advanced machine learning methods. The single-channel method introduced based on the proposed metrics can be used for robust and reliable sleep stage classification from all dimensions required for real-time applications.

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ÖzCovid-19 gibi solunum yolu enfeksiyonlarının erken tespiti, hastalığın daha kolay tedavisine ve hastanın daha rahat bir süre geçirmesine yol açarak ciddi komplikasyon olasılığını azaltabilir. Öksürme ve hapşırma gibi solunum seslerinin sıklığı, şiddeti ve türü (kuru veya balgamlı), hastalığın teşhisi, tedavisi ve davranışlarının tespitinde tıp uzmanları için çıkarılabilen zengin bilgiler taşımaktadır. Bunun için, makine veya derin öğrenimine dayalı otomatik yaklaşımların geliştirilmesi oldukça önemlidir. Center for Open Science (OSFHOME), 2020 yılında güncellediği veri küme üzerine, bu alanda çalışan araştırmacıları, ses kayıtlarını kullanarak hastalık seslerinin otomatik algılanması için makine öğrenimi modelleri oluşturmaya davet etti. Veri seti, "Pfizer Digital Medicine Challenge" için oluşturulmuştur ve amacı öksürme ve hapşırma gibi seslerinin tespiti için makine öğrenimi modellerinin geliştirilmesidir. Veri seti üç parçaya ayrılmıştır; eğitim, doğrulama ve test kümeleri. Sunulan çalışmada, bu veri seti üzerine yeni bir makine öğrenimi sistemi önerildi. Eğitim, doğrulama ve test örneklerinden öznitelikler elde edildikten sonra, dört farklı sınıflandırıcının parametrelerini hesaplamak için doğrulama veri kümesi kullanıldı ve son aşamada test veri kümesi üzerine sınıflandırma gerçekleştirildi. Elde edilen sonuçlara göre, radyal tabanlı çekirdek fonksiyonlu destek vektör makine (DVM) sınıflandırıcısı solunum seslerini diğer seslere karşı, %76 civarında bir doğruluk oranıyla diğer sınıflandırıcılara göre daha başarılı sınıflandırdı.