Robotin ajurijärjestelmän modularisointi liitännäisarkkitehtuurilla

Factory lines are nowadays filled with intelligent systems that can perform various tasks without human interaction. To reach the current level of intelligence and automation, The significance of software in industrial robotics has increased dramatically. That creates new challenges in software design for such environments, which are then tackled with new software platforms and frameworks. This thesis takes an existing test automation platform and designs a new architecture based on plugins for it. The platform is used in functional testing of smartphones. The redesign aims to increase the modularity of the architecture, and thus allow for a more flexible deployment of the system in various hardware configurations. To verify the successfulness of the new architecture, a modularity analysis is performed for both the old and the new architectures. The analysis focuses on cohesion and coupling of the classes and modules in the systems. Both the old and the new platforms are implemented in Python, so the research process will evaluate the feasibility of manual modularity analysis for a dynamically typed programming language, as these kind of analyses are usually performed on a statically typed languages utilizing static analysis tools. The new architecture was shown to increase the cohesion, and decrease the coupling of the platform, which indicates an increase in the overall modularity of the platform. The analysis itself was found to be tedious, and the dynamic nature of Python increases the chance of errors in determining the coupling and cohesion of a component. A possibility of modifying a refactoring tool to aid in a such analysis was discussed.Tehdaslinjastot koostuvat nykyään älykkäistä järjestelmistä, jotka kykenevät toimimaan ilman ihmisen ohjausta. Merkittävä tekijä tämän muutoksen takana on ohjelmistojen kehittyminen, ja niiden merkityksen kasvu teollisuudessa. Tämä luo ohjelmistosuunnitteluun uusia haasteita, joita on ratkottu uusilla sovellusalustoilla ja -kehyksillä. Tässä tutkielmassa toteutetaan uusi ohjelmistoarkkitehtuuri testiautomaatiorobotille käyttäen liitännäisarkkitehtuuria. Tavoitteena on kasvattaa alustan modulaarisuutta, mikä mahdollistaa sen joustavan käytön erilaisissa järjestelmissä, jotka koostuvat erilaisista roboteista, antureista ja sensoreista. Uuden toteutuksen soveltuvuuden varmistamiseksi tässä tutkielmassa suoritetaan modulaarisuusanalyysi molemmille järjestelmille. Analyysissä perehdytään järjestelmien luokkien ja moduulien yhteenkuuluvuuteen (eng. cohesion) sekä riippuvuuksiin (eng. coupling). Järjestelmä toteutetaan Python-kielellä, joten tutkimuksessa selvitetään modulaarisuusanalyysin soveltuvuutta dynaamisesti tyypitetylle ohjelmointikielelle. Tutkimuksessa todettiin luokkien yhteenkuuluvuuden kasvaneen ja moduulien riippuvuuksien vähentyneen, mikä kertoo järjestelmän modulaarisuuden kasvusta. Analyysi itsessään todettiin työlääksi, ja sen huomattiin kasvattavan tulosten virhettä, koska moduulien väliset vuorovaikuttamiset eivät välttämättä olleet yksikäsitteisiä. Tutkimuksessa pohdittiin mahdollisuudesta muokata olemassa olevia refaktorointityökaluja siten, että niitä voisi hyödyntää tämänkaltaisen analyysin tekemisessä

Investigating Concurrency in the Co-Simulation Orchestration Engine for INTO-CPS

There is a tendency to expect, that taking advantage of multicore systems by using concurrency improves the performance of an application. To investigate if this is true, a case study was performed where different concurrency principles were applied to an existing application called the Co-Simulation Orchestration Engine (COE), which did not utilize concurrency. This was explored in the context of Co-Simulation using the Functional Mock-up Interface, as applications executing Co-Simulations should be performant to enable the use of increasingly complex models.Co-Simulation can be useful in the development of Cyber-Physical Systems, as it can be used to simulate coupled technical systems or models and thereby examine the behavior of the systems.The investigation was carried out by refactoring the COE to make it suitable for implementing concurrency by limiting the spawning of threads and synchronization between threads, along with maximizing the workload for each thread. Three different concurrency features were used in three different implementations: Parallel collections, futures, and actors, which were evaluated based on selected quality attributes. These implementations were tested against the non-refactored sequential COE and each other by performing different simulations using different models.The case study showed, that concurrency can be used to increase the performance of the COE in some cases. Based on the analysis carried out in this thesis project, a set of guidelines were created to generalize the process of applying concurrency to an existing application

A heuristic-based approach to code-smell detection

Encapsulation and data hiding are central tenets of the object oriented paradigm. Deciding what data and behaviour to form into a class and where to draw the line between its public and private details can make the difference between a class that is an understandable, flexible and reusable abstraction and one which is not. This decision is a difficult one and may easily result in poor encapsulation which can then have serious implications for a number of system qualities. It is often hard to identify such encapsulation problems within large software systems until they cause a maintenance problem (which is usually too late) and attempting to perform such analysis manually can also be tedious and error prone. Two of the common encapsulation problems that can arise as a consequence of this decomposition process are data classes and god classes. Typically, these two problems occur together – data classes are lacking in functionality that has typically been sucked into an over-complicated and domineering god class. This paper describes the architecture of a tool which automatically detects data and god classes that has been developed as a plug-in for the Eclipse IDE. The technique has been evaluated in a controlled study on two large open source systems which compare the tool results to similar work by Marinescu, who employs a metrics-based approach to detecting such features. The study provides some valuable insights into the strengths and weaknesses of the two approache

A Service-Oriented Approach for Network-Centric Data Integration and Its Application to Maritime Surveillance

Maritime-surveillance operators still demand for an integrated maritime picture better supporting international coordination for their operations, as looked for in the European area. In this area, many data-integration efforts have been interpreted in the past as the problem of designing, building and maintaining huge centralized repositories. Current research activities are instead leveraging service-oriented principles to achieve more flexible and network-centric solutions to systems and data integration. In this direction, this article reports on the design of a SOA platform, the Service and Application Integration (SAI) system, targeting novel approaches for legacy data and systems integration in the maritime surveillance domain. We have developed a proof-of-concept of the main system capabilities to assess feasibility of our approach and to evaluate how the SAI middleware architecture can fit application requirements for dynamic data search, aggregation and delivery in the distributed maritime domain

On Preserving the Behavior in Software Refactoring: A Systematic Mapping Study

Context: Refactoring is the art of modifying the design of a system without altering its behavior. The idea is to reorganize variables, classes and methods to facilitate their future adaptations and comprehension. As the concept of behavior preservation is fundamental for refactoring, several studies, using formal verification, language transformation and dynamic analysis, have been proposed to monitor the execution of refactoring operations and their impact on the program semantics. However, there is no existing study that examines the available behavior preservation strategies for each refactoring operation. Objective: This paper identifies behavior preservation approaches in the research literature. Method: We conduct, in this paper, a systematic mapping study, to capture all existing behavior preservation approaches that we classify based on several criteria including their methodology, applicability, and their degree of automation. Results: The results indicate that several behavior preservation approaches have been proposed in the literature. The approaches vary between using formalisms and techniques, developing automatic refactoring safety tools, and performing a manual analysis of the source code. Conclusion: Our taxonomy reveals that there exist some types of refactoring operations whose behavior preservation is under-researched. Our classification also indicates that several possible strategies can be combined to better detect any violation of the program semantics

Improving variability of applications using adaptive object-models

Tese de mestrado integrado. Engenharia Informática e Computação. Universidade do Porto. Faculdade de Engenharia. 201

An approach to safely evolve preprocessor-based C program families.

Desde os anos 70, o pré-processador C é amplamente utilizado na prática para adaptar sistemas para diferentes plataformas e cenários de aplicação. Na academia, no entanto, o pré-processador tem recebido fortes críticas desde o início dos anos 90. Os pesquisadores têm criticado a sua falta de modularidade, a sua propensão para introduzir erros sutis e sua ofuscação do código fonte. Para entender melhor os problemas de usar o pré-processador C,considerando a percepção dos desenvolvedores, realizamos 40 entrevistas e uma pesquisa entre 202 desenvolvedores. Descobrimos que os desenvolvedores lidam com três problemas comuns na prática: erros relacionados à configuração, testes combinatórios e compreensão do código. Os desenvolvedores agravam estes problemas ao usar diretivas não disciplinadas, as quais não respeitam a estrutura sintática do código. Para evoluir famílias de programas de forma segura, foram propostas duas estratégias para a detecção de erros relacionados à configuração e um conjunto de 14 refatoramentos para remover diretivas não disciplinadas. Para lidar melhor com a grande quantidade de configurações do código fonte, a primeira estratégia considera todo o conjunto de configurações do código fonte e a segunda estratégia utiliza amostragem. Para propor um algoritmo de amostragem adequado, foram comparados 10 algoritmos com relação ao esforço (número de configurações para testar) e capacidade de detecção de erros (número de erros detectados nas configurações da amostra). Com base nos resultados deste estudo, foi proposto um algoritmo de amostragem. Estudos empíricos foram realizados usando 40 sistemas C do mundo real. Detectamos 128 erros relacionados à configuração, enviamos 43 correções para erros ainda não corrigidos e os desenvolvedores aceitaram 65% das correções. Os resultados de nossa pesquisa mostram que a maioria dos desenvolvedores preferem usar a versão refatorada,ou seja,disciplinada do código fonte,ao invés do código original com as diretivas não disciplinadas. Além disso,os desenvolvedores aceitaram 21 (75%) das 28 sugestões enviadas para transformar diretivas não disciplinadas em disciplinadas. Nossa pesquisa apresenta resultados úteis para desenvolvedores de código C durante suas tarefas de desenvolvimento, contribuindo para minimizar o número de erros relacionados à configuração, melhorar a compreensão e a manutenção do código fonte e orientar os desenvolvedores para realizar testes combinatórios.Since the 70s, the C preprocessor is still widely used in practice in a numbers of projects, including Apache,Linux ,and Libssh, totail or systems to different platforms and application scenarios. In academia,however, the preprocess or has received strong critic is msinceatl east the early 90s. Researchers have criticized its lack of separation of concerns, its proneness to introduce subtle errors, and its obfuscation of the source code. To better understand the problems of using the C preprocessor, taking the perception of developers into account, we conducted 40 interviewsandasurveyamong 202 developers. We found that developers deal with three common problems in practice: configuration-related bugs, combinatorial testing, and code comprehension. Developers aggravate these problems when using undisciplined directives (i.e., bad smells regarding preprocessor use), which are preprocessor directives thatdo notrespect thesyntactic structureof thesource code. To safely evolve preprocessor based program families, we proposed strategies to detect configuration-relatedbugs and bad smells, and a set of 14 refactorings to remove bad smells. To better deal with exponential configuration spaces, our strategies uses variability-aware analysis that considers the entire set of possible configurations, and sampling, which allows to reuse C tools that consider only one configuration at a time to detect bugs. To propose a suitable sampling algorithm, we compared 10 algorithms with respect to effort (i.e., number of configurations to test) andbug-detection capabilities (i.e.,numberofbugs detected in the sampled configurations). Based on the results, we proposed a sampling algorithm with an useful balance between effort and bug-detection capability. We performed empirical studies using a corpus of 40 C real-world systems. We detected 128 configuration-related bugs, submitted 43 patches to fix bugs not fixed yet, and developers accepted 65% of the patches. The results of our survey show that most developers prefer to use the refactored (i.e., disciplined) version of the code instead of the original code with undisciplined directives. Furthermore, developers accepted 21 (75%) out of 28 patches submitted to refactor undisciplined into disciplined directives. Our work presents useful findings for C developers during their development tasks, contributing to minimize the chances of introducing configuration-related bugs and bad smells, improve code comprehension, and guide developers to perform combinatorial testing

Analysis and Transformation of Configurable Systems

Static analysis tools and transformation engines for source code belong to the standard equipment of a software developer. Their use simplifies a developer's everyday work of maintaining and evolving software systems significantly and, hence, accounts for much of a developer's programming efficiency and programming productivity. This is also beneficial from a financial point of view, as programming errors are early detected and avoided in the the development process, thus the use of static analysis tools reduces the overall software-development costs considerably. In practice, software systems are often developed as configurable systems to account for different requirements of application scenarios and use cases. To implement configurable systems, developers often use compile-time implementation techniques, such as preprocessors, by using #ifdef directives. Configuration options control the inclusion and exclusion of #ifdef-annotated source code and their selection/deselection serve as an input for generating tailor-made system variants on demand. Existing configurable systems, such as the linux kernel, often provide thousands of configuration options, forming a huge configuration space with billions of system variants. Unfortunately, existing tool support cannot handle the myriads of system variants that can typically be derived from a configurable system. Analysis and transformation tools are not prepared for variability in source code, and, hence, they may process it incorrectly with the result of an incomplete and often broken tool support. We challenge the way configurable systems are analyzed and transformed by introducing variability-aware static analysis tools and a variability-aware transformation engine for configurable systems' development. The main idea of such tool support is to exploit commonalities between system variants, reducing the effort of analyzing and transforming a configurable system. In particular, we develop novel analysis approaches for analyzing the myriads of system variants and compare them to state-of-the-art analysis approaches (namely sampling). The comparison shows that variability-aware analysis is complete (with respect to covering the whole configuration space), efficient (it outperforms some of the sampling heuristics), and scales even to large software systems. We demonstrate that variability-aware analysis is even practical when using it with non-trivial case studies, such as the linux kernel. On top of variability-aware analysis, we develop a transformation engine for C, which respects variability induced by the preprocessor. The engine provides three common refactorings (rename identifier, extract function, and inline function) and overcomes shortcomings (completeness, use of heuristics, and scalability issues) of existing engines, while still being semantics-preserving with respect to all variants and being fast, providing an instantaneous user experience. To validate semantics preservation, we extend a standard testing approach for refactoring engines with variability and show in real-world case studies the effectiveness and scalability of our engine. In the end, our analysis and transformation techniques show that configurable systems can efficiently be analyzed and transformed (even for large-scale systems), providing the same guarantees for configurable systems as for standard systems in terms of detecting and avoiding programming errors

tuProlog Manual

tuProlog is a light-weight Prolog system for distributed applications and infrastructures, intentionally designed around a minimal core extensible via libraries. tuProlog natively supports multi-paradigm programming, providing a clean, seamless integration model between Prolog and mainstream object-oriented languages -- namely Java, for tuProlog Java version, and any .NET-based language (C#, F#..), for tuProlog .NET version. This manual documents the tuProlog features as of version 3.