Research On Pen-Based Software System For Dynamic Geometry

Education Informationization, as an important State Policy, applies Information Technologies in education so as to develop educational resources, optimize educational process and accelerate education modernization. It not only need the continuous improvement of the hardware, such as devices and so on, but also requires the innovation of software in ideology and methodology, which is the target of education reform in higher level. It is the human-oriented techniques which could improve teaching efficiency based on current achievements in Education Informationization. Both teachers and students have been getting great benefits from Computer Aided Teaching which goes towards the development of multimedia, intelligent, and friendly interaction between human and machine. However, there are still technical roadblocks in the software to achieve highly effective interaction between teachers and students in class, which is becoming a main bottleneck of Education Informationization. What is needed in such king software is the natural user interface techniques which could support the continuous and intelligent interaction between user and computer.Human-computer interaction(HCI) is the study of interaction between users and computers. Interaction occurs at the user interface(UI) include both software and hardware. The process of UI can be divided into three periods. Batch mode, Command Line and GUI, each kind of UI style has been dominate in the specific period. Now the research of next generation of UI has focused on the Post-WIMP (Non-WIMP) user interface which goes towards the development of human-oriented techniques. Among, the study of pen-based user interface with the metaphor of pen and paper has become the hot field both in research and industry.In this thesis, we apply the techniques of pen-based user interface to Dynamic Geometry software which supports Geometric Constraints Resolving. Major research aspects and innovative achievements are listed in the following. First, the thesis outlines the requirements of the pen-based dynamic geometry software. On the analysis of the requirements we propose a software framework for the pen-based dynamic geometry software, and discuss the key techniques including strokes collecting technique, sketch and gesture recognition technique and dynamic geometry constraints resolving algorithm.Second, we construct the interactive context model, on the basis of the model we propose a context-aware method. Then we describe the sketch and gesture recognition method based on the context-aware method.Third, we extend LIMO Algorithm's usage scope with grouping geometries. The principle of grouping is the freedom degree of the geometry, such as fixed points, dragged points, semi-free points and so on. Through this enhanced LIMO Algorithm, any point can be set as a dragged point so that the user could drag any point to investigate the geometry transformation.Forth, an intelligent pen-based whiteboard system (IIPW) for dynamic geometry is designed and implemented. IIPW can be used to add handwriting, outline and recognize geometry and manipulate interface elements with pen gestures. Through extended LIMO algorithm dynamic geometric constraint solving and dynamic geometric visualization are supported. We discuss IIPW's architecture and its key functions, and gives application examples. Experimental results show IIPW has higher task completion efficiency and user satisfaction.