Research On Awareness In Real-Time CSCW Based On Ubiquitous Environment

For the limitation of awareness capability of wireless handheld devices and the negative influence of unbalanced distribution of resources that different collaborative sites hold, there exists a great many CSCW problems related to ubiquitous environment. Environment context, device context and user context were researched to promote computing systems' initiative and intelligence. Smart interaction and interface were studied to alleviate perceive trouble brought by redundant information.A novel algorithm based on discrete system neural network was presented to filter redundant remote control points and related user self-defined visual awareness scheme was proposed. The proposed algorithm and scheme can greatly centralize users' intention to enhance the virtual awareness and promote the collaborative effeciency.A novel scheme based on grouping was proposed to mask the details of shared documents. By applying such scheme, the reviewing and recognizing obstacle problems that brought by redundant objects on the canvas were solved.Two novel algorithms, called machine learning algorithm and changeable scale algorithm respectively, were proposed to predict the trace of remote control point. Machine learning algorithm enhanced the basic dead-reckoning algorithm by adjusting prediction formula dynamically with previous difference between predicted point and actual one. Changeable scale algorithm strengthened dead-reckoning algorithm and machine learning algorithm respectively by adjusting prediction weight with the distance between the original dragged control point and the end point predicted by the two basic algorithms. Related experiments show that two novel algorithms, compared with basic algorithm, received higher precision to some extent.A novel prediction algorithm was proposed to predict users' interest by extending current focus regions. Lazy download method was adopted on wireless handheld devices by using the corresponding results of the prediction. The predicted focus not only helped users understand others' intention, but also helped wireless handheld devices pre-download the needed fragment of documents in real-time CSCW;the response time for handheld systems and users' waiting time were reduced.A video communication technology based on bi-level video coding at very low bit rates is proposed, which give preference to the outline features of scenes in the networks with limited bandwidth, rather than giving highest priority to the "basic colors" of an image as in conventional DCT-based compression methods. It can be used in video communications on a limited bandwidthas low as 10 kbit/s.An approach to real-time facial feature tracking and 2D expression parameterization was introduced. As human face provides enormous information and a friendly interface in intelligent human computer interaction (HCI) applications, it is selected as visual performance of awareness on limited bandwidth networks. A 2D face animation parameter (2D FAP) system was designed to rebuild a 2D face animation on the received site. It can be used in video communications on a limited bandwidth as low as 1~2 kbit/s.