Multi-axis Inertial Sensors Research Articles

Classification and comparison of human activities by machine learning

The current study of human activity recognition and classification has been an important part of promoting the development of science and technology in society. Human activity recognition and classification are in several fields, such as competitive sports, criminal investigation field, etc. As the field of micro-electromechanics continues to evolve, more accurate human recognition is becoming possible, with wearable multi-axis inertial sensors that allow us to visually detect the desired data. In this paper, the data of 19 human activities for 8 testers are feature extracted and normalized. The data are divided into training and test sets by machine learning models: support vector machine (SVR) classification, XGBoost classification, and logistic regression. The experiment was repeated 10 times to take the average value. The models were then scored, and by comparing integrated machine learning with traditional machine learning, it was found that integrated learning improved by 5%−29% in terms of accuracy compared to traditional machine learning.

Zero-velocity atom interferometry using a retroreflected frequency-chirped laser

Atom interferometry using stimulated Raman transitions in a retroreflected configuration is the first choice in high precision measurements because it provides low phase noise, high quality Raman wavefront and simple experimental setup. However, it cannot be used for atoms at zero velocity because two pairs of Raman lasers are simultaneously resonant. Here we report a method which allows to lift this degeneracy by using a frequency chirp on the Raman lasers. Using this technique, we realize a Mach-Zehnder atom interferometer hybridized with a force balanced accelerometer which provides horizontal acceleration measurements with a short-term sensitivity of $3.2\times 10^{-5}$ m.s$^{-2}$/$\sqrt{Hz}$. We check at the level of precision of our experiment the absence of bias induced by this method. This technique could be used for multiaxis inertial sensors, tiltmeters or atom interferometry in a microgravity environment.

704 三軸半導体加速度計のマトリックス感度計測について : 多軸慣性センサの標準に関する研究 第4報

704 三軸半導体加速度計のマトリックス感度計測について : 多軸慣性センサの標準に関する研究 第4報