Ying Zheng and John B. Morrell [5] propose a real-time haptic feedback system that actively senses and guides a
person to proper upright posture by using 7 force-sensitive resistors (FSRs) for posture detection and 6 vibrotactile
actuators (“tactors”) for haptic feedback; but it was limited to one position and it forced users to use a single sitting
position. On the contrary, Paul Allie and Doug Kokot [6] studied about the natural motion of human body, especially
movement of spine, while seated to offer a new thinking of dynamic back support in chair design. The researchers
recommended that the design of a chair should follow the motion of the body to allow different postures. The impact
of different reclined seating postures on typing performance and comfort for people with lower back pain was
investigated and posture had impact on typing performance. But, the authors suggested more experiment and
improved fixtures [7].