Title page for ETD etd-02242012-003403

Type of Document Master's Thesis
Author Chandrasekar, Samantha
Author's Email Address csamantha@vt.edu
URN etd-02242012-003403
Title Performance Improvement and Feature Enhancement of WriteOn
Degree Master of Science
Department Computer Science and Applications
Advisory Committee
Advisor Name Title
Tront, Joseph G. Committee Chair
Balci, Osman Committee Member
Ribbens, Calvin J. Committee Member
  • Screen Capture Codec
  • Computer-assisted teaching
  • Electronic Ink
  • Tablet PC
Date of Defense 2008-05-28
Availability unrestricted
A Tablet PC is a portable computing device which combines a regular notebook computer with a digitizing screen that interacts with a complementary electronic pen stylus. The pen allows the user to input data by writing on or by tapping the screen. Like a regular notebook computer, the user can also perform tasks using the mouse and keyboard. A Tablet PC gives the users all the features of a regular notebook computer along with the support to recognize, process, and store electronic/digital ink, enabling a user to make and save hand-written notes or data. In institutions of teaching and learning, instructors often use computer-based materials like web pages, PowerPoint® slides, etc., to explain subject matter. The ability to annotate on presentation information using the electronic stylus of a Tablet PC has attracted the attention of the academic community to use the Tablet PC as a potential tool for increasing the effectiveness of presentations in teaching and learning. Tablet PC-based applications such as OneNote®, WindowsJournal® and Classroom Presenter have been developed to enhance note-taking in classrooms based on the fact that a pen stylus is a more natural form of input device for making notes on the computer as compared to the regular keyboard and mouse. Although tools like OneNote®, WindowsJournal® enhanced the note-taking process on the Tablet PC, they lacked the ability to allow the user to directly annotate on the lecture content. Classroom Presenter provides the ability to integrate classroom notes and the presentation material by allowing the instructors and students to annotate over the lecture material. However, all the above tools lacked the ability to allow a user to take notes over the output window of an arbitrary application like Excel, an active simulator or a movies players output. The Tablet PC based tool, WriteOn, developed at Virginia Tech, addresses this drawback.

WriteOn, when deployed on the Tablet PC in a classroom environment, allows the instructor to utilize electronic ink to annotate on top of any application window visible on the Tablet PC display screen, including those that play active content like a movie or simulation.

WriteOn facilitates a user to annotate over a dynamic application window by activating its virtual transparency surface called the eVellum (electronic vellum). The user can view a movie or an active simulation running in the eVellum background because of its transparent color. The user can deactivate the eVellum to make it invisible by “piercing” it if he/she wishes to access the desktop or an application window under the vellum window. WriteOn provides the instructor with the ability to broadcast a composite of the dynamic lecture content and ink annotations to the students in real-time. The term dynamic lecture contents is meant to indicate that the content being annotated need not be static words on a background, but may also be window contents that are changing in time. Using WriteOn, the students can make their own notes by writing on the eVellum enabled on top of the lecture stream window without losing visibility of the lecture. The instructor/student can save the ink annotations along with base lecture material as a movie file. The ability of WriteOn to improve classroom presentation and student note-taking as shown by initial tests, were pedagogically very useful. However, in order to deploy WriteOn on large scale in classrooms as an active and effective teaching tool of choice, several aspects of the application had to be improved.

One aspect of the application that needed improvement was the user interface. The primitive Graphical User Interface (GUI) of the WriteOn tool was not easily usable by instructors and students from non-computer science backgrounds. The second aspect needing improvement was the operational performance of the application in terms of its CPU resource utilization. The WriteOn tool has shown to have operational performance issues during the screen capture process. This research therefore aims to address improvements in the GUI to make it more user friendly and increase the operational performance to the point where the user does not notice degradation of a base lecture application. Incorporation of these improvements has led us to rename the application as WriteOn1.0.

WriteOn1.0 implements a picture-based GUI that comprises of two forms: a main form that appears shortly after WriteOn1.0 starts and a toolbar. The WriteOn1.0 toolbar appears in the center of the top edge of the display as soon as the user initiates a task like a screen recording session, by clicking on the appropriate menu button on the main form. The toolbar provides the user, accessibility to perform all the desired activities like annotating, screen recording, presentation broadcast, and piercing of the eVellum by a single-click of the appropriate menu icon. Tool tips that appear when the user points the mouse over a picture icon on the toolbar, explain the task that shall be performed when he/she clicks on the underlying menu icon. WriteOn1.0 introduces a window-like resizable and movable eVellum called the scalable eVellum that it activates in the area of interest specified by the user. Unlike the first implementation of the eVellum which had a fixed location and spanned the entirety of the user’s desktop window, the instructor/student define the dimensions of the scalable eVellum and can choose to re-dimension, relocate and pierce through it at any point of time during a session. WriteOn1.0 also introduces the transparent mode of operation wherein the instructor/student, without having to deactivate the scalable eVellum can access any underlying window by a right-click of the mouse on the eVellum surface while the ink annotations are intact on the foreground,.

WriteOn1.0 addresses the operational performance issues observed during a screen capture session in WriteOn by capturing the activities only in the area of interest of the user for recording and broadcasting. By combining this scheme with a with a lossless screen capture codec called the MSU screen capture codec that has a high-compression ratio and that is optimized for speed for data compression, WriteOn1.0 greatly improves the operational CPU performance of the tool.

WriteOn1.0 employs various technologies to implement its features. The improvements to operational performance are implemented by using the MSU screen codec from Moscow State University’s Graphics and Media Lab. Microsoft®’s Video for Windows Framework (VfW) and WindowsMedia Player API’s are used to realize the module that records the screen activities to an AVI file while DirectShow of DirectX and ConferenceXP API’s are used for streaming presentations over a network. WriteOn1.0, with its features like its scalable eVellum, good operational performance and picture-based GUI is aimed at potentially making it a teaching tool of choice across classrooms and changing the method of classroom instruction of courses involving dynamic content.

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