Study On Key Problems About Usability Of Wearable Computer

Wearable computer is a new type of mobile computing device which can make the users being able to get information, to exchange and deal with it at anytime and anywhere. With the development of Wearable computing technology, wearable computers are increasingly used in various fields, accordingly the availability has become an urgent question that needs to address. But the research in this area just started, except from applying traditional methods in usability to solve some of the interaction problems, the research in usability reflected by special Human-Computer interaction remains blank. Such as comfort of wearable computer, special reliability built by human-environment restrict, the difficult degree of operating are the main factors in availability usability of wearable computers.This research topic is from the National High-tech Research Development Program (863 Program):(Project Number:2006AA01Z113). This paper focus the study on some key and typical questions that affect the availability of wearable computers, such as comfort of wearable computer, optimal model of oscillation affected by human vibration environment, the difficult degree of operating. The main contents include:1. The intensive research on the factors affecting the performance of wearable computer includes several aspects:the shape coefficient affected by different system configurations, to ensure the best body part according to the load area and load capacity. Apply the law of RULA to quantitative analyze the operating postural priority corresponding each wearable body-part.2. By applying the wearable decision-making model set by multi-objective fuzzy decision-making mechanism and combining with the research on a wearable computing system, this paper developed an optimal wear program, and further makes an evaluation of the past program.3. Make the tests for mechanical driving point impedance and transmissibility of the human body, use three-DOF parallel model to build vibration model of sitting posture, to get the corresponding impedance of sitting posture driving point and transmissibility of body oscillation.4. Taking above arm, chest, waist, abdomen, upper thigh for the research objects, we test and research the two types of human vibration environments. In the research on the first type of the human body's vibration environment, it shows that the oscillation of body part affected both by the vibration source and transmissibility of body. When frequency of vibration source is low, vibration environment is equal to first category body vibration environment. According to the characteristics of human motion, the frequency of the second category of vibration environment is low. When it's walking, the vibration of upper thigh is more significant than the other parts; when it's running, there was no significant difference among all tested parts.5. Make the theoretical study and finite element simulation analysis on wearable mainboard, which is greatest influenced by vibration. Applying "group and refinement", using orthogonal design to resolve vibration optimize model based on the researching mainboard.6. Based on Fitts'law, set up an special model of click performance for the input device of wearable computer-Twiddler. Compared with the mouse click performance model, it indicates that the performance of former is lower. At the same time, we also studied the influence of visual feedback device on the Twiddler click performance. After the research for the relation between the click amount of information and click performance, we pointed out that 1/15 is the best ratio between objective width and interface width for Twiddler operating. Several innovation achievements of this paper are listed below:1. Set up the wearable decision-making model which makes it possible to process the quantitative analysis and assessment on the wearable system. This study improves the current study from the aspects of subjectivity, limitations.2. Study the vibration environment of human body and analyze the characteristics of the vibration environments caused by human body motion.3. Apply the wearablity into the optimal design of mainboard oscillation.4. Set up a Twiddler performance model and, through comparison, indicate that the low click efficiency of the wearable computer is the defect of its availability. This paper is show the design standard of GUI object width for wearable computer.