Causes and Symptoms of Upper Abdomen Pain. 1  Abdominal Aortic Aneurysm - This condition materializes due to a weak area in the aorta wall. Over time, the wall may rupture due to its weakened condition. As the aorta is the largest artery in the body, this can be a serious condition.
Principles of Motion Sensing. Sensors able to detect three-dimensional motion have been commercially available for several decades and have been used in automobiles, aircraft and ships. However, initial size, power consumption and price had prevented their mass adoption in consumer electronics. While there are other kinds of motion detector technologies available commercially, there are four principle types of motion sensors which are important for motion processing in the consumer electronics market.
Ultrasonic sensors are based on measuring the properties of sound waves with frequency above the human audible range. They are based on three physical principles: time of flight, the Doppler effect, and the attenuation of sound waves. Ultrasonic sensors are non-intrusive in that they do not require physical contact with their target, and can detect certain clear or shiny targets otherwise obscured to some vision-based sensors. On the other hand, their measurements are very sensitive to temperature and to the angle of the target.