This paper presents JAVENGA, which is an acronym for JAva-based Visualization Environment for Network and Graph Algorithms. It is a new visualization software for educational purposes. It includes visualizations of many well-known graph and network algorithms. However, besides simple algorithms the tool also illustrates a visualization of a quite complex one, such as the Network Simplex algorithm. The recommended tool includes a graph editor where directed and undirected graphs can be drawn, it allows users to give input to an algorithm and then see its visualization in a user-controlled way, and finally it incorporates a solution window where one can see the values of variables at each step of algorithm execution. JAVENGA, as its name states, has been implemented in Java language and it can be run either as an applet or as a Java application. Further, one can execute the program either locally or remotely via the Web. It can be used by instructors as auxiliary teaching material in the context of a graph theory or network optimization course. Besides, instructors can use the tool to grade students' assignments or exams. Students can also use the software in a self-learning approach. ß

Please scroll down for article-it is on subsequent pagesWith 12,500 members from nearly 90 countries, INFORMS is the largest international association of operations research (O.R.) and analytics professionals and students. INFORMS provides unique networking and learning opportunities for individual professionals, and organizations of all types and sizes, to better understand and use O.R. and analytics tools and methods to transform strategic visions and achieve better outcomes. For more information on INFORMS, its publications, membership, or meetings visit O perations Research (OR) instructors use visualizations to help teach graph algorithms and data structures.Algorithm visualization is an illustration of abstract concepts included in computer algorithms, making use of either static or dynamic (animated) computer graphics. In this paper we present new software that includes an animated demonstration of the uncapacitated primal network simplex algorithm. The aim of the animation software is twofold. First, it aims to help OR students understand the algorithm. The algorithm is difficult to grasp for many students because it generates a sequence of rooted trees. Second, it aims to enable OR instructors to explain each iteration of the algorithm visually with minimal effort. The software can be used in combinatorial optimization, graph theory, and similar courses. The software has been implemented as a Java applet, is freely available and highly interactive, and can be accessed through the Web. The software shows the solution process through textual information and depicts the relevant steps in pseudo code using multiple views.

The teaching experiences of the network simplex algorithm to postgraduate students at our department, lead us to develop a visualization software which aims to support the instructor in his effort to explain the algorithm to the students. In addition we believe that the software will help students in their endeavor to understand the aforementioned algorithm which is quite complex, as it involves many concurrent mathematical and visual transformations.