QOE ASSESSMENT AND CONTROL IN NETWORKED HAPTIC GAMES

Abstract

In recent years, with the advancement of high speed communication networks, multimedia applications which consists of a collection of multiple media such as text, graphics, images, sound, and video became popular. Due to the difference of network delay is large among the terminals, simultaneous output of media cannot be done. Therefore, Quality of Experience (QoE) such as synchronization quality of media at each terminal or consistency among the terminals may seriously be degraded. In order to investigate the influences of network delay on such kinds of QoE assessment, the focus is on networked weight balance game and a networked balloon bursting game. To solve the above causes, it is necessary to examine influences of various factors as well as on the collaborative work with the network delay to carry out Quality of Service (QoS) control more efficiently. This is very important to improve collaborative work not only in the 3D virtual space but also in the daily life industries such as construction. Moreover, QoE assessments and QoS control are required to address in order to know that how the softness features change, when the network delay becomes larger. It is preferred to perform palpation and remote surgery in medical fields. In the networked balance game, the researcher examined the effects of network delay and moving velocity on the effectiveness of the work where two users collaboratively lift up a weighted ball with haptic sense in a virtual environment. Also, the researcher examined the influence of the initial position of the ball. Through the use of haptic interface device in the networked balloon bursting game, the researcher illustrated that how accurately each subject can perceive the difference of softness by QoE assessment in a networked virtual environment. By evaluating the QoE, the researcher also looked into how local lag affected people's perceptions of softness with haptic sense in a networked virtual space. The researcher dealt with a networked balloon bursting game that featured two balloons with various softness values. In the assessment, the subjects determined whether the softness of the balloon is “same”, “softer” or “harder”. Furthermore, the researcher examines the effect of adaptive reaction force control on human perception of softness with haptic sense in a networked virtual environment by QoE assessment. To maintain the consistency of the game states between terminals, the researcher produces the local lag, which is set to the network iii delay, at each terminal; however, as the local lag increases, the softness of balloon becomes harder. The adaptive reaction force control solves the problem by changing the elastic coefficient according to the local lag. Assessment results demonstrate that the adaptive reaction force control can keep the human perception of softness constant for a wide range of the local lag.