Syntax Trees Visualization in Language Processing Courses

F.J. Almeida-Martínez, J. Urquiza-Fuentes. Ninth IEEE International Conference on Advanced Learning Technologies (ICALT) 2009, Pages 597-601

Abstract. This paper describes the educational tool VAST. We designed VAST to be used in compiler and language processing courses. The current version allows generating and visualizing syntax trees and their construction process. The main advantages of VAST follow: it is designed to be as independent from the parser generator as possible, it allows students to visualize the behaviour of parsers they develop, and it has an interface designed to easily handle huge syntax trees. We describe different ways of using VAST in educational settings as well as a usability evaluation.

A Survey of Successful Evaluations of Program Visualization and Algorithm Animation Systems

J. Urquiza-Fuentes, J.Á. Velázquez-Iturbide. Trans. Comput. Educ. 9(2), June 2009, Pages 1-21

Abstract. This article reviews successful educational experiences in using program and algorithm visualizations (PAVs). First, we survey a total of 18 PAV systems that were subject to 33 evaluations. We found that half of the systems have only been tested for usability, and those were shallow inspections. The rest were evaluated with respect to their educational effectiveness. Script-based systems seem to be well suited for the viewing, responding, and changing engagement levels, while compiler-based systems do well for the construction and presenting engagement levels. Finally, we analyze additional PAV features of successful evaluations and hypothesize that they are relevant.

Visualization of Syntax Trees for Language Processing Courses

F.J. Almeida-Martínez, J. Urquiza-Fuentes, J.Á. Velázquez-Iturbide. Journal of Universal Computer Science 15(7), 2009, Pages 1546-1561 

Abstract. This article describes the educational tool VAST. We designed VAST to be used in compiler and language processing courses. The current version allows generat- ing and visualizing syntax trees and their construction process. The main advantages of VAST follow: it is designed to be as independent from the parser generator as possible, it allows students to visualize the behavior of parsers they develop, and it has an inter- face designed to easily handle huge syntax trees. Finally, we describe two satisfactory preliminary evaluations from the usability and educational points of view.

Improving a Zoom+Pan Interface with Overview+Detail or Focus+Context Features: A Comparative Evaluation

J. Urquiza-Fuentes, C.A. Lázaro-Carrascosa and J.Á. Velázquez-Iturbide. In Engineering the User Interface From Research to Practice, 2008, Pages 221-238

Abstract. We present an evaluation of adding Focus+Context vs. Overview+Deatil features to a Zoom+Pan interface. The framework of the evaluation is an interface to deal with large sets of items with specific structural properties (sequential order, heterogeneous sizes), and behavior requirements (flexible interaction, maximizing screen space, minimizing changes in screen). The evaluation involved 43 participants. We studied the effect of three factors (namely, experience with the tasks, size of the sets, and tasks performed with the same set) on effectiveness, efficiency and user's satisfaction. The results show that experienced users of the interface enhanced with the Focus+Context features obtained the best results on effectiveness and efficiency. Furthermore, a satisfaction questionnaire showed that users felt more comfortable with the Focus+Context approach.

An approach to effortless construction of program animations

J.A. Velázquez-Iturbide and C. Pareja-Flores and J. Urquiza-Fuentes. Computers & Education 50(1), January 2008, Pages 179-192

Abstract. Program animation systems have not been as widely adopted by computer science educators as we might expect from the firm belief that they can help in enhancing computer science education. One of the most notable obstacles to their adoption is the considerable effort that the production of program animations represents for the instructor. We present here an approach to reduce such a workload based on the automatic generation of visualizations and animations. The user may customize them in a user-friendly way to construct more expressive program animations. These operations are carried out by means of a user-friendly manipulation based on the metaphor of office documents. We have applied this approach to the functional paradigm by extending the WinHIPE programming environment. Finally, we report on the successful results of an evaluation performed to measure its ease of use.