DSpot: Test Amplification for Automatic Assessment of Computational Diversity

Context: Computational diversity, i.e., the presence of a set of programs that all perform compatible services but that exhibit behavioral differences under certain conditions, is essential for fault tolerance and security. Objective: We aim at proposing an approach for automatically assessing the presence of computational diversity. In this work, computationally diverse variants are defined as (i) sharing the same API, (ii) behaving the same according to an input-output based specification (a test-suite) and (iii) exhibiting observable differences when they run outside the specified input space. Method: Our technique relies on test amplification. We propose source code transformations on test cases to explore the input domain and systematically sense the observation domain. We quantify computational diversity as the dissimilarity between observations on inputs that are outside the specified domain. Results: We run our experiments on 472 variants of 7 classes from open-source, large and thoroughly tested Java classes. Our test amplification multiplies by ten the number of input points in the test suite and is effective at detecting software diversity. Conclusion: The key insights of this study are: the systematic exploration of the observable output space of a class provides new insights about its degree of encapsulation; the behavioral diversity that we observe originates from areas of the code that are characterized by their flexibility (caching, checking, formatting, etc.).Comment: 12 page

Applications of a System of Tools in the Construction and Implementation of Multimedia Courses

Los profesores tienen el reto de usar las NTIC de forma creativa. Muchos de ellos poseen materiales de instrucción en diferentes soportes, pero necesitan de herramientas que les faciliten la construcción de cursos multimedia interactivos. Este trabajo aborda la aplicación de un sistema de herramientas, que viabiliza la construcción y administración de cursos multimedia. El sistema ha sido aplicado por profesores y estudiantes de la Facultad de Economía de la UH, así como por profesores y estudiantes de la Facultad de Informática de la Universidad de Cienfuegos, en la construcción e implementación de cursos multimedia que han sido utilizados en el modelo de enseñanza presencial y semipresencial.The professors have the challenge of using the NTIC in a creative way. Many of them possess instruction materials in different supports, but they need of tools that facilitate them the construction of interactive multimedia courses. This work approaches the application of a system of tools that viabiliza the construction and administration of multimedia courses. The system has been applied by professors and students of the Economy Faculty of the Havana University, as well as for professors and students of the Computer science Faculty of the Cienfuegos University, in the construction and implementation of multimedia courses that have been used in the pattern of present teaching and semipresencial