WeaFQAs: A Software Product Line Approach for Customizing and Weaving Efficient Functional Quality Attributes

Fecha de Lectura de Tesis: 10 de julio de 2018Los atributos de calidad funcionales (FQA) son aquellos que tienen una clara implicación en la funcionalidad del sistema, es decir, existen unos componentes específicos que deben ser incorporados a la arquitectura software del sistema para satisfacer sus requisitos de atributos de calidad. Ejemplos de FQAs son seguridad, usabilidad, o persistencia. Modelar estos atributos es una tarea compleja. Por un lado, se componen de muchas características relacionadas, por ejemplo seguridad está compuesto, entre otros, por autenticación, confidencialidad y encriptación. Tienen dependencias entre ellos, por ejemplo, seguridad puede ser requerido por usabilidad o persistencia. Por otro lado, tienen muchos puntos de variabilidad: una aplicación concreta puede requerir autenticación y control de acceso mientras que otra puede necesitar sólo encriptación. Además, su funcionalidad suele estar dispersa afectando a varios componentes del sistema en desarrollo. El objetivo de esta tesis es definir una línea de productos software orientada a aspectos que permita: (1) modelar las similitudes y la variabilidad de los FQAs desde las primeras etapas del proceso de desarrollo, (2) gestionar las dependencias existentes entre los FQAs, (3) independizar el modelado de los FQAs de la arquitectura de la aplicación afectada, (4) configurar los FQAs en base a los requisitos de cada aplicación teniendo además en cuenta propiedades no funcionales como el rendimiento y el consumo energético de cada solución, (5) incorporar las configuraciones a la arquitectura de la aplicación de manera automática; y (6) gestionar la evolución de los FQAs cuando los requisitos cambien en el futuro. Como resultado se ha definido WeaFQAs, un proceso software para gestionar los FQAs que cubre todos los puntos mencionados. Se han realizado y comparado dos instanciaciones de WeaFQAs usando diferentes lenguajes de variabilidad y de modelado, además de proporcionar soporte con una herramienta basada en el lenguaje CVL

The case of KAO

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia InformáticaRequirements engineering aims at eliciting, analyzing, specifying, validating and managing system requirements. When eliciting system requirements, it is possible to use various approaches, including goal-oriented and aspect-oriented approaches. Although those are two well-known approaches, they are seldom used in conjunction. On the other hand, when using goal-oriented approaches, one common and usual problem is the fact that some of the goals repeat themselves all over the system. This makes goal-oriented models to have a boost in complexity because of the repeating goals, and thus, making the evolution of this model harder than necessary. This complexity could be minimized if an aspect-oriented approach would be used. The big advantage of using a hybrid approach, in our case goal-oriented and aspect-oriented one is the possibility to identify all the scattered goals and modularize them as aspects. In this way we can represent this kind of goal (now an aspect) only once in the model. This means the complexity of the model will be greatly reduced and the readability of the model will also be improved. The final result will be an evolution that could be easily controlled, thus minimizing errors. Although this seems a good idea, there are some challenges to overcome when merging goals and aspects. First of all, a notation and a set of rules must be built in order to compose the model. In order to do this we will use patterns based on roles, as these will help elaborating the model. This work will present an approach that will make possible after modeling the system with a goal-oriented approach, identify aspects and then refine the model taking into account the aspects. In order to accomplish this, the KAOS methodology will be extended with aspects

Estudo do impacto de transientes elétricos em protocolos de comunicação em sistemas embarcados

O aumento da complexidade e responsabilidade dos dispositivos embarcados nos veículos hoje, tem orientado os esforços no desenvolvimento de sistemas de controle para que estes sejam mais rápidos, precisos, robustos e principamente seguros. Com isso, estes dispositivos estão levando os protocolos de comunicação a um patamar inédito de exigência, tanto no quesito de capacidade como confiabilidade. Protocolos como CAN, CAN-FD e FlexRay entre outros, tem sido utilizados devido às suas características de segurança e a capacidade de atender aos requisitos temporais dos diversos circuitos embarcados. O desenvolvimento e utilização cada vez mais frequente de dispositivos focados em segurança, fazem com que a comunicação entre os diversos componentes destes dispositivos seja exigida ao máximo, levando à necessidade de respostas confiáveis ao extremo. Sistemas como freios ABS, suspensão ativa, frenagem autonoma de emergência, controle de velocidade e distância adaptativo, entre outros, que envolvem várias ECUs distribuídas ao longo do veículo, dispões de frações de segundo para a reação do sistema, entre o sinal de entrada e a atuação correspondente, demandando uma comunicação segura e tolerante à falhas. Os veículos hoje estão passando por grandes mudanças conceituais, trazendo cada vez mais elementos onde o funcionamento demanda mais energia das fontes de alimentação. Diversos sistemas existentes nos veículos geram ruídos como os Transientes Elétricos Rápidos, ou "Electric Fast Transient" (EFT), que estão presentes nas mais simples operações cotidianas do veículo, como ligar e desligar o farol, o ar condicionado, o limpador de para brisas, ou mesmo o acionamento de iluminação diurna (DRL), etc. Neste trabalho foram realizados diversos ensaios, utilizando ECUs com diferentes funções e protocolos, para identificar a susceptibilidade dos referidos sistemas e os protocolos à presença destes ruídos. Visando atender às normas IEC 62228 e a ISO26262, este trabalho demandou o projeto e construção de dois circuitos eletrônicos diferentes, um circuito observando os dados de tempos de subida e de descida (rise and fall time) dos pulsos de EFT, e outro observando a arquitetura do layout da placa de circuito impresso (PCB), as suas entradas, saídas, componentes, etc. Estes ensaios visaram identificar o quanto estes protocolos são suscetíveis à estes tipos de ruídos, utilizando métricas de análise baseadas nos tempos de latência e variação de jitter dos pacotes de comunicação.The increasing complexity and accountability of embedded devices in vehicles today has driven efforts to develop control systems to make them faster, accuratest, safest, robustest. Thus, these devices are taking communication protocols to an unprecedented level of demand, both in terms of capacity and reliability. Protocols such as CAN, CANFD and FlexRay among others have been used due to their safety characteristics and the ability to meet the time requirements of various embedded circuits. The increasing development and use of safety-focused devices, means that communication between the various components of these devices is required to the utmost, leading to the need for extremely reliable responses. Systems such as ABS brakes, active suspension, autonomous emergency braking, adaptative cruise control, among others, which involve various ECUs distributed throughout the vehicle, have milliseconds for system reaction, between input signal and concrete actuation, requiring safe and failure tolerant communication. Vehicles today are undergoing major conceptual changes, bringing more and more elements whose operation require more energy from power supplies. These systems generate noise such as "Electric Fast Transient" (EFT), which are present in the simplest daily operations of the vehicle, such as turning the headlight on, the air conditioner, the windscreen wiper, or even the daytime running light (DRL), etc. In this work several tests were carried out, using different ECUs with different functions and different protocols to identify the susceptibility of these systems and the protocols to these noises. In order to comply with IEC 62228 and ISO 26262 standards, this work required the design and construction of two different electronic circuits, one circuit observing the rise and fall time data of the EFT pulses, and the other observing the architecture of the printed circuit board (PCB) layout, its inputs and outputs, components, etc. These tests aimed to identify how susceptible these protocols are to these types of noise, using analysis metrics based on latency time and jitter variation of communication packets

Modeling, enacting, and integrating custom crowdsourcing processes

Crowdsourcing (CS) is the outsourcing of a unit of work to a crowd of people via an open call for contributions. Thanks to the availability of online CS platforms, such as Amazon Mechanical Turk or CrowdFlower, the practice has experienced a tremendous growth over the past few years and demonstrated its viability in a variety of fields, such as data collection and analysis or human computation. Yet it is also increasingly struggling with the inherent limitations of these platforms: each platform has its own logic of how to crowdsource work (e.g., marketplace or contest), there is only very little support for structured work (work that requires the coordination of multiple tasks), and it is hard to integrate crowdsourced tasks into stateof-the-art business process management (BPM) or information systems. We attack these three shortcomings by (1) developing a flexible CS platform (we call it Crowd Computer, or CC) that allows one to program custom CS logics for individual and structured tasks, (2) devising a BPMN-based modeling language that allows one to program CC intuitively, (3) equipping the language with a dedicated visual editor, and (4) implementing CC on top of standard BPM technology that can easily be integrated into existing software and processes. We demonstrate the effectiveness of the approach with a case study on the crowd-based mining of mashup model patterns

Achieving Autonomic Web Service Compositions with Models at Runtime

Over the last years, Web services have become increasingly popular. It is because they allow businesses to share data and business process (BP) logic through a programmatic interface across networks. In order to reach the full potential of Web services, they can be combined to achieve specifi c functionalities. Web services run in complex contexts where arising events may compromise the quality of the system (e.g. a sudden security attack). As a result, it is desirable to count on mechanisms to adapt Web service compositions (or simply called service compositions) according to problematic events in the context. Since critical systems may require prompt responses, manual adaptations are unfeasible in large and intricate service compositions. Thus, it is suitable to have autonomic mechanisms to guide their self-adaptation. One way to achieve this is by implementing variability constructs at the language level. However, this approach may become tedious, difficult to manage, and error-prone as the number of con figurations for the service composition grows. The goal of this thesis is to provide a model-driven framework to guide autonomic adjustments of context-aware service compositions. This framework spans over design time and runtime to face arising known and unknown context events (i.e., foreseen and unforeseen at design time) in the close and open worlds respectively. At design time, we propose a methodology for creating the models that guide autonomic changes. Since Service-Oriented Architecture (SOA) lacks support for systematic reuse of service operations, we represent service operations as Software Product Line (SPL) features in a variability model. As a result, our approach can support the construction of service composition families in mass production-environments. In order to reach optimum adaptations, the variability model and its possible con figurations are verifi ed at design time using Constraint Programming (CP). At runtime, when problematic events arise in the context, the variability model is leveraged for guiding autonomic changes of the service composition. The activation and deactivation of features in the variability model result in changes in a composition model that abstracts the underlying service composition. Changes in the variability model are refl ected into the service composition by adding or removing fragments of Business Process Execution Language (WS-BPEL) code, which are deployed at runtime. Model-driven strategies guide the safe migration of running service composition instances. Under the closed-world assumption, the possible context events are fully known at design time. These events will eventually trigger the dynamic adaptation of the service composition. Nevertheless, it is diffi cult to foresee all the possible situations arising in uncertain contexts where service compositions run. Therefore, we extend our framework to cover the dynamic evolution of service compositions to deal with unexpected events in the open world. If model adaptations cannot solve uncertainty, the supporting models self-evolve according to abstract tactics that preserve expected requirements.Alférez Salinas, GH. (2013). Achieving Autonomic Web Service Compositions with Models at Runtime [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34672TESI

Combining SOA and BPM Technologies for Cross-System Process Automation

This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation

Energy-Efficient Software

The energy consumption of ICT is growing at an unprecedented pace. The main drivers for this growth are the widespread diffusion of mobile devices and the proliferation of datacenters, the most power-hungry IT facilities. In addition, it is predicted that the demand for ICT technologies and services will increase in the coming years. Finding solutions to decrease ICT energy footprint is and will be a top priority for researchers and professionals in the field. As a matter of fact, hardware technology has substantially improved throughout the years: modern ICT devices are definitely more energy efficient than their predecessors, in terms of performance per watt. However, as recent studies show, these improvements are not effectively reducing the growth rate of ICT energy consumption. This suggests that these devices are not used in an energy-efficient way. Hence, we have to look at software. Modern software applications are not designed and implemented with energy efficiency in mind. As hardware became more and more powerful (and cheaper), software developers were not concerned anymore with optimizing resource usage. Rather, they focused on providing additional features, adding layers of abstraction and complexity to their products. This ultimately resulted in bloated, slow software applications that waste hardware resources -- and consequently, energy. In this dissertation, the relationship between software behavior and hardware energy consumption is explored in detail. For this purpose, the abstraction levels of software are traversed upwards, from source code to architectural components. Empirical research methods and evidence-based software engineering approaches serve as a basis. First of all, this dissertation shows the relevance of software over energy consumption. Secondly, it gives examples of best practices and tactics that can be adopted to improve software energy efficiency, or design energy-efficient software from scratch. Finally, this knowledge is synthesized in a conceptual framework that gives the reader an overview of possible strategies for software energy efficiency, along with examples and suggestions for future research