Development of a 3d tool for visualization of different software artifacts and their relationships

Este trabajo se enfoca en el desarrollo de una herramienta de visualización de software que permite analizar diferentes artefactos de software como código fuente y bases de datos relacionales. Por su naturaleza, la herramienta creada propone una metáfora basada en desarrollos anteriores del campo de visualización de software. La primera parte del documento de tesis presenta un estado del arte en el área de visualización de software, esto incluye la forma en cómo esta área aporta al proceso de evolución de software, punto muy importante en la ingeniería de software. Posteriormente se presenta la fundamentación básica de SeeIT 3D (nombre de la herramienta desarrollada): su metáfora, métricas, mecanismos para entrada de datos y tecnologías que hacen parte de la arquitectura interna. Luego, con el fin de validar la funcionalidad de la herramienta y dar soporte a los fundamentos en los que se basa, se evaluaron un conjunto de proyectos de código abierto escritos en lenguaje Java, que por su tamaño medio e historia bien definida en el área que representan, proveen un buen marco de evaluación. Finalmente como resultado del trabajo de tesis es posible concluir que la visualización de software realmente da un buen soporte a las tareas asociadas al proceso de evolución de software, brindando mecanismos que permiten comprender más fácilmente los artefactos producidos durante el desarrollo de software. De igual manera se concluyen que SeeIT 3D es una buena aproximación y un avance en el campo dadas sus capacidades. / Abstract.This work is focused in the development of a software visualization tool that is able to analyze different software artifacts such as source code and relational databases. Because of its nature, the tool proposes a metaphor based on previous works developed in the software visualization field. The beginning of the thesis document presents a state of art of software visualization; it includes how visualization supports the process of software evolution. After that the basis of SeeIT 3D (name of the developed tool) is presented e.g. the metaphor, metrics, input mechanism and technologies that conform its internal architecture. In order to validate the functionality of the tool and give support to the concepts it is based on, a set of open source projects written in Java language was evaluated. These projects have a medium size and a well-defined history in the field they represent that provide an adequate evaluation framework for the tool. Finally as a result of the thesis work it is possible to conclude that software visualization really provides enough support for the task associated with the evolution process of software systems. It is provided by giving mechanisms that allow understanding the produced software artifacts easily. It is also possible to concluded that SeeIT 3D is a good approximation and a step forward in the field due to its capabilities.Maestrí

The Effectiveness of Aural Instructions with Visualisations in E-Learning Environments

Based on Mayer’s (2001) model for more effective learning by exploiting the brain’s dual sensory channels for information processing, this research investigates the effectiveness of using aural instructions together with visualisation in teaching the difficult concepts of data structures to novice computer science students. A small number of previous studies have examined the use of audio and visualisation in teaching and learning environments but none has explored the integration of both technologies in teaching data structures programming to reduce the cognitive load on learners’ working memory. A prototype learning tool, known as the Data Structure Learning (DSL) tool, was developed and used first in a short mini study that showed that, used together with visualisations of algorithms, aural instructions produced faster student response times than did textual instructions. This result suggested that the additional use of the auditory sensory channel did indeed reduce the cognitive load. The tool was then used in a second, longitudinal, study over two academic terms in which students studying the Data Structures module were offered the opportunity to use the DSL approach with either aural or textual instructions. Their use of the approach was recorded by the DSL system and feedback was invited at the end of every visualisation task. The collected data showed that the tool was used extensively by the students. A comparison of the students’ DSL use with their end-of-year assessment marks revealed that academically weaker students had tended to use the tool most. This suggests that less able students are keen to use any useful and available instrument to aid their understanding, especially of difficult concepts. Both the quantitative data provided by the automatic recording of DSL use and an end-of-study questionnaire showed appreciation by students of the help the tool had provided and enthusiasm for its future use and development. These findings were supported by qualitative data provided by student written feedback at the end of each task, by interviews at the end of the experiment and by interest from the lecturer in integrating use of the tool with the teaching of the module. A variety of suggestions are made for further work and development of the DSL tool. Further research using a control group and/or pre and post tests would be particularly useful

Evaluating Extensible 3D (X3D) Graphics For Use in Software Visualisation

3D web software visualisation has always been expensive, special purpose, and hard to program. Most of the technologies used require large amounts of scripting, are not reliable on all platforms, are binary formats, or no longer maintained. We can make end-user web software visualisation of object-oriented programs cheap, portable, and easy by using Extensible (X3D) 3D Graphics, which is a new open standard. In this thesis we outline our experience with X3D and discuss the suitability of X3D as an output format for software visualisation

CoMoVA - A comprehension measurement framework for visualization systems

Despite the burgeoning interest shown in visualizations by many disciplines, there yet remains the unresolved question concerning comprehension. Is the concept that is being communicated through the visual easily grasped and clearly interpreted? Visual comprehension is that characteristic of any visualization system, which deals with how efficiently and effectively users are able to grasp the underlying concepts through suitable interactions provided for exploring the visually represented information. Comprehension has been considered a very complex subject, which is intangible and subjective in nature. Assessment of comprehension can help to determine the true usefulness of visualization systems to the intended users. A principal contribution of this research is the formulation of an empirical evaluation framework for systematically assessing comprehension support provided by a visualization system to its intended users. To assess comprehension i.e. to measure this seemingly immeasurable factor of visualization systems, we propose a set of criteria based on a detailed analysis of information flow from the raw data to the cognition of information in human mind. Our comprehension criteria are adapted from the pioneering work of two eminent researchers - Donald A. Norman and Aaron Marcus, who have investigated the issues of human perception and cognition, and visual effectiveness respectively. The proposed criteria have been refined with the help of opinions from experts. To gauge and verify the efficacy of these criteria in a practical sense, they were then applied to a bioinformatics visualization study tool and an immersive art visualization environment. Given the vast variety of users and their visualization goals, it may be noted that it is difficult for one to decide on the effectiveness of different visualization tools/techniques in a context independent fashion. We therefore propose an innovative way of evaluating a visualization technique by encapsulating it in a visualization pattern where it is seen as a solution to the visualization problem in a specific context. These visualization patterns guide the tool users/evaluators to compare, understand and select appropriate visualization tools/techniques. Lastly, we propose a novel framework named as CoMoVA (Comprehension Model for Visualization Assessment) that incorporates 'context of use', visualization patterns, visual design principles and important cognitive principles into a coherent whole that can be used to effectively tell us in a more quantifiable manner the benefits of visual representations and interactions provided by a system to the intended audience. Our approach of evaluation of visualization systems is similar to other questionnaire-based approaches such as SUMI (Software Usability Measurement Inventory), where all the questions deal with the measurement of a common trait. We apply this framework to two static software visualization tools in the software visualization domain to demonstrate the practical benefits of using such a framework

Quality-Aware Tooling

Programming is a fascinating activity that can yield results capable of changing people lives by automating daily tasks or even completely reimagining how we perform certain activities. Such a great power comes with a handful of challenges, with software maintainability being one of them. Maintainability cannot be validated by executing the program but has to be assessed by analyzing the codebase. This tedious task can be also automated by the means of software development. Programs called static analyzers can process source code and try to detect suspicious patterns. While these programs were proven to be useful, there is also an evidence that they are not used in practice. In this dissertation we discuss the concept of quality-aware tooling —- an approach that seeks a promotion of static analysis by seamlessly integrating it into development tools. We describe our experience of applying quality-aware tooling on a core distribution of a development environment. Our main focus is to provide live quality feedback in the code editor, but we also integrate static analysis into other tools based on our code quality model. We analyzed the attitude of the developers towards the integrated static analysis and assessed the impact of the integration on the development ecosystem. As a result 90% of software developers find the live feedback useful, quality rules received an overhaul to better match the contemporary development practices, and some developers even experimented with a custom analysis implementations. We discovered that live feedback helped developers to avoid dangerous mistakes, saved time, and taught valuable concepts. But most importantly we changed the developers' attitude towards static analysis from viewing it as just another tool to seeing it as an integral part of their toolset

Verification, slicing, and visualization of programs with contracts

Tese de doutoramento em Informática (área de especialização em Ciências da Computação)As a specification carries out relevant information concerning the behaviour of a program, why not explore this fact to slice a program in a semantic sense aiming at optimizing it or easing its verification? It was this idea that Comuzzi, in 1996, introduced with the notion of postcondition-based slicing | slice a program using the information contained in the postcondition (the condition Q that is guaranteed to hold at the exit of a program). After him, several advances were made and different extensions were proposed, bridging the two areas of Program Verification and Program Slicing: specifically precondition-based slicing and specification-based slicing. The work reported in this Ph.D. dissertation explores further relations between these two areas aiming at discovering mutual benefits. A deep study of specification-based slicing has shown that the original algorithm is not efficient and does not produce minimal slices. In this dissertation, traditional specification-based slicing algorithms are revisited and improved (their formalization is proposed under the name of assertion-based slicing), in a new framework that is appropriate for reasoning about imperative programs annotated with contracts and loop invariants. In the same theoretical framework, the semantic slicing algorithms are extended to work at the program level through a new concept called contract based slicing. Contract-based slicing, constituting another contribution of this work, allows for the study of a program at an interprocedural level, enabling optimizations in the context of code reuse. Motivated by the lack of tools to prove that the proposed algorithms work in practice, a tool (GamaSlicer) was also developed. It implements all the existing semantic slicing algorithms, in addition to the ones introduced in this dissertation. This third contribution is based on generic graph visualization and animation algorithms that were adapted to work with verification and slice graphs, two specific cases of labelled control low graphs.Tendo em conta que uma especificação contém informação relevante no que diz respeito ao comportamento de um programa, faz sentido explorar este facto para o cortar em fatias (slice) com o objectivo de o optimizar ou de facilitar a sua verificação. Foi precisamente esta ideia que Comuzzi introduziu, em 1996, apresentando o conceito de postcondition-based slicing que consiste em cortar um programa usando a informação contida na pos-condicão (a condição Q que se assegura ser verdadeira no final da execução do programa). Depois da introdução deste conceito, vários avanços foram feitos e diferentes extensões foram propostas, aproximando desta forma duas áreas que até então pareciam desligadas: Program Verification e Program Slicing. Entre estes conceitos interessa-nos destacar as noções de precondition-based slicing e specification-based slicing, que serão revisitadas neste trabalho. Um estudo aprofundado do conceito de specification-based slicing relevou que o algoritmo original não é eficiente e não produz slices mínimos. O trabalho reportado nesta dissertação de doutoramento explora a ideia de tornar mais próximas essas duas áreas visando obter benefícios mútuos. Assim, estabelecendo uma nova base teórica matemática, os algoritmos originais de specification-based slicing são revistos e aperfeiçoados | a sua formalizacão é proposta com o nome de assertion-based slicing. Ainda sobre a mesma base teórica, os algoritmos de slicing são extendidos, de forma a funcionarem ao nível do programa; alem disso introduz-se um novo conceito: contract-based slicing. Este conceito, contract-based slicing, sendo mais um dos contributos do trabalho aqui descrito, possibilita o estudo de um programa ao nível externo de um procedimento, permitindo, por um lado, otimizações no contexto do seu uso, e por outro, a sua reutilização segura. Devido à falta de ferramentas que provem que os algoritmos propostos de facto funcionam na prática, foi desenvolvida uma, com o nome GamaSlicer, que implementa todos os algoritmos existentes de slicing semântico e os novos propostos. Uma terceira contribuição é baseada nos algoritmos genéricos de visualização e animação de grafos que foram adaptados para funcionar com os grafos de controlo de fluxo etiquetados e os grafos de verificação e slicing.Fundação para a Ciência e a Tecnologia (FCT) através da Bolsa de Doutoramento SFRH/BD/33231/2007Projecto RESCUE (contrato FCT sob a referência PTDC / EIA / 65862 /2006)Projecto CROSS (contrato FCT sob a referência PTDC / EIACCO / 108995 / 2008

Conformance Checking and Simulation-based Evolutionary Optimization for Deployment and Reconfiguration of Software in the Cloud

Many SaaS providers nowadays want to leverage the cloud's capabilities also for their existing applications, for example, to enable sound scalability and cost-effectiveness. This thesis provides the approach CloudMIG that supports SaaS providers to migrate those applications to IaaS and PaaS-based cloud environments. CloudMIG consists of a step-by-step process and focuses on two core components. (1) Restrictions imposed by specific cloud environments (so-called cloud environment constraints (CECs)), such as a limited file system access or forbidden method calls, can be validated by an automatic conformance checking approach. (2) A cloud deployment option (CDO) determines which cloud environment, cloud resource types, deployment architecture, and runtime reconfiguration rules for exploiting a cloud's elasticity should be used. The implied performance and costs can differ in orders of magnitude. CDOs can be automatically optimized with the help of our simulation-based genetic algorithm CDOXplorer. Extensive lab experiments and an experiment in an industrial context show CloudMIG's applicability and the excellent performance of its two core components