Browsing by Subject "Magnetic"

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Open Access
Novel noniterative orientation estimation for wearable motion sensor units acquiring accelerometer, gyroscope, and magnetometer measurements
(IEEE, 2020) Yurtman, Aras; Barshan, Billur
We propose a novel noniterative orientation estimation method based on the physical and geometrical properties of the acceleration, angular rate, and magnetic field vectors to estimate the orientation of motion sensor units. The proposed algorithm aims that the vertical (up) axis of the earth coordinate frame is as close as possible to the measured acceleration vector and that the north axis of the earth makes an angle with the detected magnetic field vector as close as possible to the estimated value of the magnetic dip angle. We obtain the sensor unit orientation based on the rotational quaternion transformation between the earth and the sensor unit frames. We evaluate the proposed method by incorporating it into an activity recognition scheme for daily and sports activities, which requires accurately estimated sensor unit orientations to achieve invariance to the orientations at which the units are worn on the body. Using four different classifiers on a publicly available data set, the proposed methodology achieves an average activity recognition accuracy higher than the state-of-the-art methods, as well as being computationally efficient enough to be executed in real time.
Open Access
Real-time biosensing bacteria and virus with quartz crystal microbalance: recent advances, opportunities, and challenges
(Taylor & Francis, 2023-05-16) Bonyadi, Farzaneh; Kavruk, Murat; Uçak, Samet; Çetin, Barbaros; Bayramoğlu, Gülay; Dursun, Ali D.; Arıca, Yakup; Özalp, Veli C.
Continuous monitoring of pathogens finds applications in environmental, medical, and food industry settings. Quartz crystal microbalance (QCM) is one of the promising methods for real-time detection of bacteria and viruses. QCM is a technology that utilizes piezoelectric principles to measure mass and is commonly used in detecting the mass of chemicals adhering to a surface. Due to its high sensitivity and rapid detection times, QCM biosensors have attracted considerable attention as a potential method for detecting infections early and tracking the course of diseases, making it a promising tool for global public health professionals in the fight against infectious diseases. This review first provides an overview of the QCM biosensing method, including its principle of operation, various recognition elements used in biosensor creation, and its limitations and then summarizes notable examples of QCM biosensors for pathogens, focusing on microfluidic magnetic separation techniques as a promising tool in the pretreatment of samples. The review explores the use of QCM sensors in detecting pathogens in various samples, such as food, wastewater, and biological samples. The review also discusses the use of magnetic nanoparticles for sample preparation in QCM biosensors and their integration into microfluidic devices for automated detection of pathogens and highlights the importance of accurate and sensitive detection methods for early diagnosis of infections and the need for point-of-care approaches to simplify and reduce the cost of operation.