Dolby AC-3, the audio signal compression standard adopted by the United States Advanced Television System Committee (ATSC), and wildly used in other applications DVD and digital TV. In order to improve the compression quality, the AC-3 defines two block lengths for IMDCT, one 512-pt.(long block) and the other 256-pt.(short block,). In the thesis, we realize the AC-3 audio decoder on the ARM-based platform. Our simulation results show that the IMDCT takes about 66% computation time of all decode process. Since the pure software decoding time cannot meet the real time requirement in many high speed applications, we design and implement the IMDCT hardware architecture considering of shore/long transform, the memory allocation for IMDCT, and use look-up tables to reduce the computation load. The HW/SW co-design on the ARM-based platform achieves the real-time requirements.

Heutzutage sind wir von Geräten umgeben, die sowohl Hardware wie auch Software- Komponenten beinhalten. Diese Geräte unterstützen ein breites Spektrum an verschiedenen Domänen, so zum Beispiel Telekommunikation, Luftfahrt, Automobil und andere. Derartige Systeme sind überall aufzufinden und werden als Eingebettete Systeme bezeichnet, da sie zur Informationsverarbeitung in andere Produkte eingebettet werden, wobei die Informationsverarbeitung des eingebetteten Systems jedoch nicht die bezeichnende Funktion des Produkts ist. Die ständig zunehmende Komplexität moderner eingebettete Systeme erfordert die Verwendung von mehreren Komponenten um die Funktionen von einem einzelnen System zu implementieren. Eine solche Steigerung der Funktionalität führt jedoch ebenfalls zu einem Wachstum in der Entwurfs-Komplexität, die korrekt und effizient beherrscht werden muss. Neben hohen Anforderungen bezüglich Leistungsaufnahme, Performanz und Kosten hat auch Time-to-Market-Anforderungen großen Einfluss auf den Entwurf von Eingebetteten Systemen. Design Space Exploration (DSE) beschreibt die systematische Erzeugung und Auswertung von Entwurfs-Alternativen, um die Systemleistung zu optimieren und den gestellten Anforderungen an das System zu genügen. Bei der Entwicklung von Eingebetteten Systemen, speziell beim Platform-Based Design (PBD) führt die zunehmende Anzahl von Design-Entscheidungen auf mehreren Abstraktionsebenen zu einer Explosion der möglichen Kombinationen von Alternativen, was auch für aktuelle DSE Methoden eine Herausforderung darstellt. Jedoch vermag üblicherweise nur eine begrenzte Anzahl von Entwurfs-Alternativen die zusätzlich formulierten nicht-funktionalen Anforderungen zu erfüllen. Darüber hinaus beeinflusst jede Entwurfs- Entscheidung weitere Entscheidungen und damit die resultierenden Systemeigenschaften. Somit existieren Abhängigkeiten zwischen Entwurfs-Entscheidungen und deren Reihenfolge auf dem Weg zur Implementierung des Systems. Zudem gilt es zwischen einer spezifischen Heuristik für eine bestimmte DSE, welche zu verbesserten Optimierungsresultaten führt, sowie globalen Verfahren, welche ihrerseits zur Flexibilität hinsichtlich der Anwendbarkeit bei verschiedenen DSE Szenarien beitragen, abzuwägen. Um die genannten Herausforderungen zu lösen wird eine Modellgetriebene Entwicklung (englisch Model-Driven Engineering, kurz MDE) Methodik für DSE vorgeschlagen. Für diese Methodik wird ein DSE-Domain-Metamodell eingeführt um relevante DSEKonzepte wie Entwurfsraum, Entwurfs-Alternativen, Auswertungs- und Bewertungsverfahren, Einschränkungen und andere abzubilden. Darüber hinaus modelliert das Metamodell verschiedenen DSE-Frage- stellungen, was zur Verbesserung der Flexibilität der vorgeschlagenen Methodik beiträgt. Zur Umsetzung von DSE-Regeln, welche zur Steuerung, Einschränkung und Generierung der Ent- wurfs-Alternativen genutzt werden, finden Modell-zu-Modell-Transformationen Anwendung. Durch die Fokussierung auf die Zuordnung zwischen den Schichten in einem PBDAnsatz wird eine neuartige Entwurfsraumabstraktion eingeführt, um multiple Entwurfsentscheidungen als singuläres DSE Problem zu repräsentieren. Diese auf dem Categorial Graph Product aufbauende Abstraktion entkoppelt den Explorations-Algorithmus vom Entwurfsraum und ist für Umsetzung in automatisierte Werkzeugketten gut geeignet. Basierend auf dieser Abstraktion profitiert die DSE-Methode durch die eingeführte MDEMethodik als solche und ermöglicht nunmehr neue Optimierungsmöglichkeiten sowie die Verbesserung der Integration von DSE in Entwicklungsprozesse und die Spezifikation von DSE-Szenarien. / Atualmente dispositivos contendo hardware e software são encontrados em todos os lugares. Estes dispositivos prestam suporte a uma varieadade de domínios, como telecomunicações, automotivo e outros. Eles são chamados “sistemas embarcados”, pois são sistemas de processamento montados dentro de produtos, cujo sistema de processamento não faz parte da funcionalidade principal do produto. O acréscimo de funções nestes sistemas implica no aumento da complexidade de seu projeto, o qual deve ser adequadamente gerenciado, pois além de requisitos rigorosos em relação à dissipação de potência, desempenho e custos, a pressão sobre o prazo para introdução de um produto no mercado também dificulta seu projeto. Exploração do espaço de projeto (DSE) é a atividade sistemática de gerar e avaliar alternativas de projetos, com o objetivo de otimizar suas propriedades. No desenvolvimento de sistemas embarcados, especialmente em Projeto Baseado em Plataformas (PBD), metodologias de DSE atuais são desafiadas pelo crescimento do número de decisões de projeto, o qual implica na explosão da combinação de alternativas. Porém, somente algumas destas resultam em projetos que atedem os requisitos nãofuncionais. Além disso, as decisões influenciam umas às outras, de forma que a ordem em que estas são tomadas alteram a implementação final do sistema. Outro desafio é o balanço entre flexibilidade da metodologia e seu desempenho, pois métodos globais de otimização são flexíveis, mas apresentam baixo desempenho. Já heurísticas especialmente desenvolvidas para o cenário de DSE em questão apresentam melhor desempenho, porém dificilmente são aplicáveis a diferentes cenários. Com o intuito de superar os desafios é proposta uma metodologia de projeto dirigido por modelos (MDE) adquada para DSE. Um metamodelo do domínio de DSE é definido para representar conceitos como espaço de projeto, métodos de avaliação e restrições. O metamodelo também representa diferentes problemas de DSE aprimorando a flexibilidade da metodologia. Regras de transformações de modelos implementam as regras de DSE, as quais são utilizadas para restringir e guiar a geração de projetos alternativos. Restringindo-se ao mapeamento entre camadas no PBD é proposta uma abstração para representar o espaço de projeto. Ela representa múltiplas decisões de projeto envolvidas no mapeamento como um único problema de DSE. Esta representação é adequada para a implementação em ferramentas automática de DSE e pode beneficiar o processo de DSE com uma abordagem de MDE, aprimorando a especificação de cenários de DSE e sua integração no processo de desenvolvimento. / Nowadays we are surrounded by devices containing hardware and software components. These devices support a wide spectrum of different domains, such as telecommunication, avionics, automobile, and others. They are found anywhere, and so they are called Embedded Systems, as they are information processing systems embedded into enclosing products, where the processing system is not the main functionality of the product. The ever growing complexity in modern embedded systems requires the utilization of more components to implement the functions of a single system. Such an increasing functionality leads to a growth in the design complexity, which must be managed properly, because besides stringent requirements regarding power, performance and cost, also time-to-market hinders the design of embedded systems. Design Space Exploration (DSE) is the systematic generation and evaluation of design alternatives, in order to optimize system properties and fulfill requirements. In embedded system development, specifically in Platform-Based Design (PBD), current DSE methodologies are challenged by the increasing number of design decisions at multiple abstraction levels, which leads to an explosion of combination of alternatives. However, only a reduced number of these alternatives leads to feasible designs, which fulfill non-functional requirements. Moreover, each design decision influences subsequent decisions and system properties, hence there are inter-dependencies between design decisions, so that the order decisions are made matters to the final system implementation. Furthermore, there is a trade-off between heuristics for specific DSE, which improves the optimization results, and global optimizers, which improve the flexibility to be applied in different DSE scenarios. In order to overcome the identified challenges an MDE methodology for DSE is proposed. For this methodology a DSE Domain metamodel is proposed to represent relevant DSE concepts such as design space, design alternatives, evaluation method, constraints and others. Moreover, this metamodel represents different DSE problems, improving the flexibility of the proposed framework. Model transformations are used to implement DSE rules, which are used to constrain, guide, and generate design candidates. Focusing on the mapping between layers in a PBD approach, a novel design space abstraction is provided to represent multiple design decisions involved in the mapping as a single DSE problem. This abstraction is based on Categorical Graph Product, decoupling the exploration algorithm from the design space and being well suited to be implemented in automatic exploration tools. Upon this abstraction, the DSE method can benefit from the MDE methodology, opening new optimization opportunities, and improving the DSE integration into the development process and specification of DSE scenarios.

Heutzutage sind wir von Geräten umgeben, die sowohl Hardware wie auch Software- Komponenten beinhalten. Diese Geräte unterstützen ein breites Spektrum an verschiedenen Domänen, so zum Beispiel Telekommunikation, Luftfahrt, Automobil und andere. Derartige Systeme sind überall aufzufinden und werden als Eingebettete Systeme bezeichnet, da sie zur Informationsverarbeitung in andere Produkte eingebettet werden, wobei die Informationsverarbeitung des eingebetteten Systems jedoch nicht die bezeichnende Funktion des Produkts ist. Die ständig zunehmende Komplexität moderner eingebettete Systeme erfordert die Verwendung von mehreren Komponenten um die Funktionen von einem einzelnen System zu implementieren. Eine solche Steigerung der Funktionalität führt jedoch ebenfalls zu einem Wachstum in der Entwurfs-Komplexität, die korrekt und effizient beherrscht werden muss. Neben hohen Anforderungen bezüglich Leistungsaufnahme, Performanz und Kosten hat auch Time-to-Market-Anforderungen großen Einfluss auf den Entwurf von Eingebetteten Systemen. Design Space Exploration (DSE) beschreibt die systematische Erzeugung und Auswertung von Entwurfs-Alternativen, um die Systemleistung zu optimieren und den gestellten Anforderungen an das System zu genügen. Bei der Entwicklung von Eingebetteten Systemen, speziell beim Platform-Based Design (PBD) führt die zunehmende Anzahl von Design-Entscheidungen auf mehreren Abstraktionsebenen zu einer Explosion der möglichen Kombinationen von Alternativen, was auch für aktuelle DSE Methoden eine Herausforderung darstellt. Jedoch vermag üblicherweise nur eine begrenzte Anzahl von Entwurfs-Alternativen die zusätzlich formulierten nicht-funktionalen Anforderungen zu erfüllen. Darüber hinaus beeinflusst jede Entwurfs- Entscheidung weitere Entscheidungen und damit die resultierenden Systemeigenschaften. Somit existieren Abhängigkeiten zwischen Entwurfs-Entscheidungen und deren Reihenfolge auf dem Weg zur Implementierung des Systems. Zudem gilt es zwischen einer spezifischen Heuristik für eine bestimmte DSE, welche zu verbesserten Optimierungsresultaten führt, sowie globalen Verfahren, welche ihrerseits zur Flexibilität hinsichtlich der Anwendbarkeit bei verschiedenen DSE Szenarien beitragen, abzuwägen. Um die genannten Herausforderungen zu lösen wird eine Modellgetriebene Entwicklung (englisch Model-Driven Engineering, kurz MDE) Methodik für DSE vorgeschlagen. Für diese Methodik wird ein DSE-Domain-Metamodell eingeführt um relevante DSEKonzepte wie Entwurfsraum, Entwurfs-Alternativen, Auswertungs- und Bewertungsverfahren, Einschränkungen und andere abzubilden. Darüber hinaus modelliert das Metamodell verschiedenen DSE-Frage- stellungen, was zur Verbesserung der Flexibilität der vorgeschlagenen Methodik beiträgt. Zur Umsetzung von DSE-Regeln, welche zur Steuerung, Einschränkung und Generierung der Ent- wurfs-Alternativen genutzt werden, finden Modell-zu-Modell-Transformationen Anwendung. Durch die Fokussierung auf die Zuordnung zwischen den Schichten in einem PBDAnsatz wird eine neuartige Entwurfsraumabstraktion eingeführt, um multiple Entwurfsentscheidungen als singuläres DSE Problem zu repräsentieren. Diese auf dem Categorial Graph Product aufbauende Abstraktion entkoppelt den Explorations-Algorithmus vom Entwurfsraum und ist für Umsetzung in automatisierte Werkzeugketten gut geeignet. Basierend auf dieser Abstraktion profitiert die DSE-Methode durch die eingeführte MDEMethodik als solche und ermöglicht nunmehr neue Optimierungsmöglichkeiten sowie die Verbesserung der Integration von DSE in Entwicklungsprozesse und die Spezifikation von DSE-Szenarien. / Atualmente dispositivos contendo hardware e software são encontrados em todos os lugares. Estes dispositivos prestam suporte a uma varieadade de domínios, como telecomunicações, automotivo e outros. Eles são chamados “sistemas embarcados”, pois são sistemas de processamento montados dentro de produtos, cujo sistema de processamento não faz parte da funcionalidade principal do produto. O acréscimo de funções nestes sistemas implica no aumento da complexidade de seu projeto, o qual deve ser adequadamente gerenciado, pois além de requisitos rigorosos em relação à dissipação de potência, desempenho e custos, a pressão sobre o prazo para introdução de um produto no mercado também dificulta seu projeto. Exploração do espaço de projeto (DSE) é a atividade sistemática de gerar e avaliar alternativas de projetos, com o objetivo de otimizar suas propriedades. No desenvolvimento de sistemas embarcados, especialmente em Projeto Baseado em Plataformas (PBD), metodologias de DSE atuais são desafiadas pelo crescimento do número de decisões de projeto, o qual implica na explosão da combinação de alternativas. Porém, somente algumas destas resultam em projetos que atedem os requisitos nãofuncionais. Além disso, as decisões influenciam umas às outras, de forma que a ordem em que estas são tomadas alteram a implementação final do sistema. Outro desafio é o balanço entre flexibilidade da metodologia e seu desempenho, pois métodos globais de otimização são flexíveis, mas apresentam baixo desempenho. Já heurísticas especialmente desenvolvidas para o cenário de DSE em questão apresentam melhor desempenho, porém dificilmente são aplicáveis a diferentes cenários. Com o intuito de superar os desafios é proposta uma metodologia de projeto dirigido por modelos (MDE) adquada para DSE. Um metamodelo do domínio de DSE é definido para representar conceitos como espaço de projeto, métodos de avaliação e restrições. O metamodelo também representa diferentes problemas de DSE aprimorando a flexibilidade da metodologia. Regras de transformações de modelos implementam as regras de DSE, as quais são utilizadas para restringir e guiar a geração de projetos alternativos. Restringindo-se ao mapeamento entre camadas no PBD é proposta uma abstração para representar o espaço de projeto. Ela representa múltiplas decisões de projeto envolvidas no mapeamento como um único problema de DSE. Esta representação é adequada para a implementação em ferramentas automática de DSE e pode beneficiar o processo de DSE com uma abordagem de MDE, aprimorando a especificação de cenários de DSE e sua integração no processo de desenvolvimento. / Nowadays we are surrounded by devices containing hardware and software components. These devices support a wide spectrum of different domains, such as telecommunication, avionics, automobile, and others. They are found anywhere, and so they are called Embedded Systems, as they are information processing systems embedded into enclosing products, where the processing system is not the main functionality of the product. The ever growing complexity in modern embedded systems requires the utilization of more components to implement the functions of a single system. Such an increasing functionality leads to a growth in the design complexity, which must be managed properly, because besides stringent requirements regarding power, performance and cost, also time-to-market hinders the design of embedded systems. Design Space Exploration (DSE) is the systematic generation and evaluation of design alternatives, in order to optimize system properties and fulfill requirements. In embedded system development, specifically in Platform-Based Design (PBD), current DSE methodologies are challenged by the increasing number of design decisions at multiple abstraction levels, which leads to an explosion of combination of alternatives. However, only a reduced number of these alternatives leads to feasible designs, which fulfill non-functional requirements. Moreover, each design decision influences subsequent decisions and system properties, hence there are inter-dependencies between design decisions, so that the order decisions are made matters to the final system implementation. Furthermore, there is a trade-off between heuristics for specific DSE, which improves the optimization results, and global optimizers, which improve the flexibility to be applied in different DSE scenarios. In order to overcome the identified challenges an MDE methodology for DSE is proposed. For this methodology a DSE Domain metamodel is proposed to represent relevant DSE concepts such as design space, design alternatives, evaluation method, constraints and others. Moreover, this metamodel represents different DSE problems, improving the flexibility of the proposed framework. Model transformations are used to implement DSE rules, which are used to constrain, guide, and generate design candidates. Focusing on the mapping between layers in a PBD approach, a novel design space abstraction is provided to represent multiple design decisions involved in the mapping as a single DSE problem. This abstraction is based on Categorical Graph Product, decoupling the exploration algorithm from the design space and being well suited to be implemented in automatic exploration tools. Upon this abstraction, the DSE method can benefit from the MDE methodology, opening new optimization opportunities, and improving the DSE integration into the development process and specification of DSE scenarios.

Heutzutage sind wir von Geräten umgeben, die sowohl Hardware wie auch Software- Komponenten beinhalten. Diese Geräte unterstützen ein breites Spektrum an verschiedenen Domänen, so zum Beispiel Telekommunikation, Luftfahrt, Automobil und andere. Derartige Systeme sind überall aufzufinden und werden als Eingebettete Systeme bezeichnet, da sie zur Informationsverarbeitung in andere Produkte eingebettet werden, wobei die Informationsverarbeitung des eingebetteten Systems jedoch nicht die bezeichnende Funktion des Produkts ist. Die ständig zunehmende Komplexität moderner eingebettete Systeme erfordert die Verwendung von mehreren Komponenten um die Funktionen von einem einzelnen System zu implementieren. Eine solche Steigerung der Funktionalität führt jedoch ebenfalls zu einem Wachstum in der Entwurfs-Komplexität, die korrekt und effizient beherrscht werden muss. Neben hohen Anforderungen bezüglich Leistungsaufnahme, Performanz und Kosten hat auch Time-to-Market-Anforderungen großen Einfluss auf den Entwurf von Eingebetteten Systemen. Design Space Exploration (DSE) beschreibt die systematische Erzeugung und Auswertung von Entwurfs-Alternativen, um die Systemleistung zu optimieren und den gestellten Anforderungen an das System zu genügen. Bei der Entwicklung von Eingebetteten Systemen, speziell beim Platform-Based Design (PBD) führt die zunehmende Anzahl von Design-Entscheidungen auf mehreren Abstraktionsebenen zu einer Explosion der möglichen Kombinationen von Alternativen, was auch für aktuelle DSE Methoden eine Herausforderung darstellt. Jedoch vermag üblicherweise nur eine begrenzte Anzahl von Entwurfs-Alternativen die zusätzlich formulierten nicht-funktionalen Anforderungen zu erfüllen. Darüber hinaus beeinflusst jede Entwurfs- Entscheidung weitere Entscheidungen und damit die resultierenden Systemeigenschaften. Somit existieren Abhängigkeiten zwischen Entwurfs-Entscheidungen und deren Reihenfolge auf dem Weg zur Implementierung des Systems. Zudem gilt es zwischen einer spezifischen Heuristik für eine bestimmte DSE, welche zu verbesserten Optimierungsresultaten führt, sowie globalen Verfahren, welche ihrerseits zur Flexibilität hinsichtlich der Anwendbarkeit bei verschiedenen DSE Szenarien beitragen, abzuwägen. Um die genannten Herausforderungen zu lösen wird eine Modellgetriebene Entwicklung (englisch Model-Driven Engineering, kurz MDE) Methodik für DSE vorgeschlagen. Für diese Methodik wird ein DSE-Domain-Metamodell eingeführt um relevante DSEKonzepte wie Entwurfsraum, Entwurfs-Alternativen, Auswertungs- und Bewertungsverfahren, Einschränkungen und andere abzubilden. Darüber hinaus modelliert das Metamodell verschiedenen DSE-Frage- stellungen, was zur Verbesserung der Flexibilität der vorgeschlagenen Methodik beiträgt. Zur Umsetzung von DSE-Regeln, welche zur Steuerung, Einschränkung und Generierung der Ent- wurfs-Alternativen genutzt werden, finden Modell-zu-Modell-Transformationen Anwendung. Durch die Fokussierung auf die Zuordnung zwischen den Schichten in einem PBDAnsatz wird eine neuartige Entwurfsraumabstraktion eingeführt, um multiple Entwurfsentscheidungen als singuläres DSE Problem zu repräsentieren. Diese auf dem Categorial Graph Product aufbauende Abstraktion entkoppelt den Explorations-Algorithmus vom Entwurfsraum und ist für Umsetzung in automatisierte Werkzeugketten gut geeignet. Basierend auf dieser Abstraktion profitiert die DSE-Methode durch die eingeführte MDEMethodik als solche und ermöglicht nunmehr neue Optimierungsmöglichkeiten sowie die Verbesserung der Integration von DSE in Entwicklungsprozesse und die Spezifikation von DSE-Szenarien. / Atualmente dispositivos contendo hardware e software são encontrados em todos os lugares. Estes dispositivos prestam suporte a uma varieadade de domínios, como telecomunicações, automotivo e outros. Eles são chamados “sistemas embarcados”, pois são sistemas de processamento montados dentro de produtos, cujo sistema de processamento não faz parte da funcionalidade principal do produto. O acréscimo de funções nestes sistemas implica no aumento da complexidade de seu projeto, o qual deve ser adequadamente gerenciado, pois além de requisitos rigorosos em relação à dissipação de potência, desempenho e custos, a pressão sobre o prazo para introdução de um produto no mercado também dificulta seu projeto. Exploração do espaço de projeto (DSE) é a atividade sistemática de gerar e avaliar alternativas de projetos, com o objetivo de otimizar suas propriedades. No desenvolvimento de sistemas embarcados, especialmente em Projeto Baseado em Plataformas (PBD), metodologias de DSE atuais são desafiadas pelo crescimento do número de decisões de projeto, o qual implica na explosão da combinação de alternativas. Porém, somente algumas destas resultam em projetos que atedem os requisitos nãofuncionais. Além disso, as decisões influenciam umas às outras, de forma que a ordem em que estas são tomadas alteram a implementação final do sistema. Outro desafio é o balanço entre flexibilidade da metodologia e seu desempenho, pois métodos globais de otimização são flexíveis, mas apresentam baixo desempenho. Já heurísticas especialmente desenvolvidas para o cenário de DSE em questão apresentam melhor desempenho, porém dificilmente são aplicáveis a diferentes cenários. Com o intuito de superar os desafios é proposta uma metodologia de projeto dirigido por modelos (MDE) adquada para DSE. Um metamodelo do domínio de DSE é definido para representar conceitos como espaço de projeto, métodos de avaliação e restrições. O metamodelo também representa diferentes problemas de DSE aprimorando a flexibilidade da metodologia. Regras de transformações de modelos implementam as regras de DSE, as quais são utilizadas para restringir e guiar a geração de projetos alternativos. Restringindo-se ao mapeamento entre camadas no PBD é proposta uma abstração para representar o espaço de projeto. Ela representa múltiplas decisões de projeto envolvidas no mapeamento como um único problema de DSE. Esta representação é adequada para a implementação em ferramentas automática de DSE e pode beneficiar o processo de DSE com uma abordagem de MDE, aprimorando a especificação de cenários de DSE e sua integração no processo de desenvolvimento. / Nowadays we are surrounded by devices containing hardware and software components. These devices support a wide spectrum of different domains, such as telecommunication, avionics, automobile, and others. They are found anywhere, and so they are called Embedded Systems, as they are information processing systems embedded into enclosing products, where the processing system is not the main functionality of the product. The ever growing complexity in modern embedded systems requires the utilization of more components to implement the functions of a single system. Such an increasing functionality leads to a growth in the design complexity, which must be managed properly, because besides stringent requirements regarding power, performance and cost, also time-to-market hinders the design of embedded systems. Design Space Exploration (DSE) is the systematic generation and evaluation of design alternatives, in order to optimize system properties and fulfill requirements. In embedded system development, specifically in Platform-Based Design (PBD), current DSE methodologies are challenged by the increasing number of design decisions at multiple abstraction levels, which leads to an explosion of combination of alternatives. However, only a reduced number of these alternatives leads to feasible designs, which fulfill non-functional requirements. Moreover, each design decision influences subsequent decisions and system properties, hence there are inter-dependencies between design decisions, so that the order decisions are made matters to the final system implementation. Furthermore, there is a trade-off between heuristics for specific DSE, which improves the optimization results, and global optimizers, which improve the flexibility to be applied in different DSE scenarios. In order to overcome the identified challenges an MDE methodology for DSE is proposed. For this methodology a DSE Domain metamodel is proposed to represent relevant DSE concepts such as design space, design alternatives, evaluation method, constraints and others. Moreover, this metamodel represents different DSE problems, improving the flexibility of the proposed framework. Model transformations are used to implement DSE rules, which are used to constrain, guide, and generate design candidates. Focusing on the mapping between layers in a PBD approach, a novel design space abstraction is provided to represent multiple design decisions involved in the mapping as a single DSE problem. This abstraction is based on Categorical Graph Product, decoupling the exploration algorithm from the design space and being well suited to be implemented in automatic exploration tools. Upon this abstraction, the DSE method can benefit from the MDE methodology, opening new optimization opportunities, and improving the DSE integration into the development process and specification of DSE scenarios.

Platform based ecosystems are becoming dominant models in the software engineering industry. ‘Big data’ has recently gained increased attention from both academia and practitioners and it is believed that big data affects every sector and industry. While an abundance of research focuses on big data and platform-based ecosystems, these two are typically approached as secluded spheres. This study aimed toward an investigation of big data’s role in the evolution of platform-based ecosystems in the software engineering industry. In the present thesis the influence of big data on the software engineering industry and more specifically, the impact of big data on the evolution of software ecosystems, is examined. A case study focused on a platform owner and pioneer in the software engineering industry has been conducted. This study identifies challenges and opportunities triggered by the advent of big data in context of platform-based ecosystems. Hence, considerable insight regarding the impact of big data on contemporary platform providers and the evolution of platform-centric ecosystems is gained. The findings illustrate that software ecosystems are affected by big data in a positive manner, but some identified challenges emerge and have to be tackled. Additionally, in this paper, it is suggested that both academia and practitioners should dig deeper into this relationship and identify how the evolution of platform-based ecosystems is impacted by the advent of big data.

Energy consumption is one of the most constrained requirements for the development and implementation of wireless sensor networks. Many design aspects affect energy consumption, ranging from the hardware components, operations of the sensors, the communication protocols, the application algorithms, duty cycles and others. Efficient simulation tool can be used to estimate the contribution to energy consumption of all of these factors, and significantly decrease the efforts and time spent to choose the right solution that fits best to a particular application. In this work we present design space exploration methodology for ultra low power embedded systems and wireless sensor networks. The methodology takes inspiration from Platform Based Design (PBD) paradigm and defines separate abstraction layers for all system aspects that directly contribute power consumption of target applications. To support presented methodology we built a SystemC-based discrete event simulation framework, called “PASES”, that provides power-aware simulation and analysis of wireless sensor networks and sensor nodes. Its modular architecture allows flexible, extensible and rapid modeling of custom HW platforms, SW application models, communication protocols, energy sources, environment dynamics and nodes mobility. Based on the feedback gained from PASES, the optimal and energy-efficient solution for the specific project of interest can be selected. The proposed approach improves state-of-the-art by providing fast and reliable power-aware system-level exploration for a wide range of custom applications

O conceito \"plataforma\" tem sido explorado em pesquisas sobre desenvolvimento de produtos, estratégia tecnológica e economia industrial. O uso de plataformas dentro das empresas e, mais recentemente, para mediar atividades de aglomerados ou ecossistemas de empresas têm sido reconhecidos como de grande importância na gestão de novos negócios, no desenvolvimento de novos produtos e na inovação. Google, Facebook, SAP, Microsoft e Apple são exemplos de empresas do setor de software cujas plataformas têm inspirado muitas outras empresas a desenvolverem produtos e serviços complementares. Ao analisar sistematicamente a literatura sobre plataformas, combinando análises bibliométricas e de conteúdo, foi possível verificar a existência de lacunas a serem estudadas no que se refere à teoria da evolução das plataformas e às adaptações organizacionais das empresas que se baseiam em plataformas para o desenvolvimento de seus produtos. Visando estender essa teoria, o objetivo desta tese foi investigar capacitações vinculadas ao relacionamento entre proprietárias de plataformas e desenvolvedores que complementam estas plataformas, como meio para compreender como elas evoluem de internas para externas. A abordagem metodológica escolhida foi a pesquisa qualitativa realizada mediante estudo de casos múltiplos em empresas nacionais e internacionais que atuam no setor brasileiro de software. Foram analisadas seis plataformas em organizações que são proprietárias de plataformas de software, e dezesseis empresas desenvolvedoras que contribuem com produtos ou serviços complementares a estas plataformas. Os resultados trouxeram algumas contribuições; a revisão sistemática da literatura, por exemplo, permitiu uma melhor compreensão e clareza sobre a evolução do conceito plataforma com identificação de tendências e temas emergentes para pesquisa. O estudo de casos realizado contribuiu com a identificação e a classificação de um conjunto de capacitações por tipo de plataforma, considerando a perspectiva do proprietário da plataforma e dos desenvolvedores. E como principal contribuição deste trabalho, tanto para teoria como para prática, fica a proposição de um quadro teórico estendido, que indica que para evoluir de uma plataforma interna para uma plataforma externa, as proprietárias de plataformas desenvolvem determinadas capacitações vinculadas ao relacionamento com desenvolvedores de software, de acordo com o tipo de plataforma. Em relação aos desenvolvedores, esse quadro aponta para o desenvolvimento de capacitações adaptadas ao tipo de plataforma. Espera-se que este trabalho contribua para o debate sobre plataformas e capacitações. / The concept of \"platform\" has been explored in many studies on product development, technology strategy, and industrial economy. The use of platforms within companies and, more recently, in mediating the activities within clusters or ecosystems of businesses, has been recognized as highly significant for the management of new businesses, for the development of new products, and for innovation. Google, Facebook, SAP, Microsoft and Apple are examples of companies in the software industry whose platforms have inspired many other businesses to develop complementary products and services. By systematically analyzing the literature on platforms, combining bibliometric analyses with content analyses, it was possible to observe the existence of gaps to be filled concerning the theory of the evolution of platforms, and the processes of organizational adaptation that platform-based companies undergo in the development of their products. Aiming at extending the theory, the objective of this work has been that of investigating capabilities associated to the relationships between platform owners and developers as a means to understand how platforms evolve from internal platforms to external platforms. The methodology chosen for this work was a qualitative study conducted via case study of multiple cases with national and international companies present in the Brazilian software industry. Six examples of software platform owners were examined, along with sixteen developers that contribute with products and services that extend those platforms. The results of the study make a few contributions to this topic; the systematic review of the literature, for example, allows a better, clearer understanding of the evolution of the concept of platform, identifying trends and emerging themes for research. The case studies contribute to identify and classify a set of capabilities by type of platform, considering the perspective of the owner and that of the developers. And as the main contribution of this work, both for theory and for practice, we have the proposition of an extended theoretical framework that indicates that, in order to evolve from an internal platform to an external one, the platform owners develop certain capabilities associated to their relationship with software developers, according to the type of platform. Regarding developers, this framework points to the development of capabilities adapted to the type of platform. We hope that this work will contribute to the ongoing debate about platforms and capabilities.

As today's real-time embedded systems grow increasingly ubiquitous, rising complexity ensues as more and more functionalities are integrated. Market dynamics and competitiveness further constrict the technology-to-market time requirement, consequently pushing it to the very forefront of consideration during the development process. Traditional system development approaches could no longer efficiently cope with such formidable demands, and a paradigm shift has been perceived by many as a mandate. This thesis presents a novel platform-centric SoC design method that relies on a platform-based design to expedite the overall development process. The proposed approach offers a new perspective towards the complex systems design paradigm, and can attain the desired paradigm shift through extensive reuse and flexibility. It offers a unified communication means for all sectors involved in the development process: Semiconductor vendors can use it to publish their platform specifications; Tool vendors can use it to develop and/or enhance their tools; System developers can use it to efficiently develop the system. Key technologies are also identified, namely the Extensible Markup Language (XML) and the Unified Modeling Language (UML), that realize the proposed approach. This thesis extends XML to attain a standard means for modeling, and processing a large amount of reusable platform-related data. Additionally, it employs UML's own extension mechanism to derive a UML dialect that can be used to model real-time systems and characteristics. This UML dialect, i.e. the UML profile for Codesign Modeling Framework (UML-CMF), remains compliant to the UML standard. A sub-profile within the UML profile for Codesign Modeling Framework is also developed so as to furnish a means for efficient modeling of platforms, and that can be seamlessly integrated with other real-time modeling capabilities offered by the UML-CMF. Such an effort yields a robust UML-compliant language that is suitable for a general platform-based modeling and design. A practical use of the proposed approach is demonstrated through a powerful case study that applies the approach to develop a digital camera system. The results are comparatively presented against the SpecC approach in terms of cost metrics based on the COCOMO II model.

O conceito \"plataforma\" tem sido explorado em pesquisas sobre desenvolvimento de produtos, estratégia tecnológica e economia industrial. O uso de plataformas dentro das empresas e, mais recentemente, para mediar atividades de aglomerados ou ecossistemas de empresas têm sido reconhecidos como de grande importância na gestão de novos negócios, no desenvolvimento de novos produtos e na inovação. Google, Facebook, SAP, Microsoft e Apple são exemplos de empresas do setor de software cujas plataformas têm inspirado muitas outras empresas a desenvolverem produtos e serviços complementares. Ao analisar sistematicamente a literatura sobre plataformas, combinando análises bibliométricas e de conteúdo, foi possível verificar a existência de lacunas a serem estudadas no que se refere à teoria da evolução das plataformas e às adaptações organizacionais das empresas que se baseiam em plataformas para o desenvolvimento de seus produtos. Visando estender essa teoria, o objetivo desta tese foi investigar capacitações vinculadas ao relacionamento entre proprietárias de plataformas e desenvolvedores que complementam estas plataformas, como meio para compreender como elas evoluem de internas para externas. A abordagem metodológica escolhida foi a pesquisa qualitativa realizada mediante estudo de casos múltiplos em empresas nacionais e internacionais que atuam no setor brasileiro de software. Foram analisadas seis plataformas em organizações que são proprietárias de plataformas de software, e dezesseis empresas desenvolvedoras que contribuem com produtos ou serviços complementares a estas plataformas. Os resultados trouxeram algumas contribuições; a revisão sistemática da literatura, por exemplo, permitiu uma melhor compreensão e clareza sobre a evolução do conceito plataforma com identificação de tendências e temas emergentes para pesquisa. O estudo de casos realizado contribuiu com a identificação e a classificação de um conjunto de capacitações por tipo de plataforma, considerando a perspectiva do proprietário da plataforma e dos desenvolvedores. E como principal contribuição deste trabalho, tanto para teoria como para prática, fica a proposição de um quadro teórico estendido, que indica que para evoluir de uma plataforma interna para uma plataforma externa, as proprietárias de plataformas desenvolvem determinadas capacitações vinculadas ao relacionamento com desenvolvedores de software, de acordo com o tipo de plataforma. Em relação aos desenvolvedores, esse quadro aponta para o desenvolvimento de capacitações adaptadas ao tipo de plataforma. Espera-se que este trabalho contribua para o debate sobre plataformas e capacitações. / The concept of \"platform\" has been explored in many studies on product development, technology strategy, and industrial economy. The use of platforms within companies and, more recently, in mediating the activities within clusters or ecosystems of businesses, has been recognized as highly significant for the management of new businesses, for the development of new products, and for innovation. Google, Facebook, SAP, Microsoft and Apple are examples of companies in the software industry whose platforms have inspired many other businesses to develop complementary products and services. By systematically analyzing the literature on platforms, combining bibliometric analyses with content analyses, it was possible to observe the existence of gaps to be filled concerning the theory of the evolution of platforms, and the processes of organizational adaptation that platform-based companies undergo in the development of their products. Aiming at extending the theory, the objective of this work has been that of investigating capabilities associated to the relationships between platform owners and developers as a means to understand how platforms evolve from internal platforms to external platforms. The methodology chosen for this work was a qualitative study conducted via case study of multiple cases with national and international companies present in the Brazilian software industry. Six examples of software platform owners were examined, along with sixteen developers that contribute with products and services that extend those platforms. The results of the study make a few contributions to this topic; the systematic review of the literature, for example, allows a better, clearer understanding of the evolution of the concept of platform, identifying trends and emerging themes for research. The case studies contribute to identify and classify a set of capabilities by type of platform, considering the perspective of the owner and that of the developers. And as the main contribution of this work, both for theory and for practice, we have the proposition of an extended theoretical framework that indicates that, in order to evolve from an internal platform to an external one, the platform owners develop certain capabilities associated to their relationship with software developers, according to the type of platform. Regarding developers, this framework points to the development of capabilities adapted to the type of platform. We hope that this work will contribute to the ongoing debate about platforms and capabilities.

Many companies are using platform-based product designs to fulfill the requirements of customers while maintaining low cost. However, research that integrates sustainability into platform-based product design is still limited. Considering sustainability during platform-based design process is a challenge because the total life-cycle from pre-manufacturing, manufacturing and use to post-use stages as well as economic, environmental and societal performance in these stages must be considered. In this research, an approach for quantifying sustainability is introduced and a mathematical model is developed for identifying a more sustainable platform. Data from life-cycle assessment is used to quantify environmental factors; criteria from the Product Sustainability Index (ProdSI) are used to quantify societal factors. The Analytic Hierarchical Process method is used to assess relative importance of societal factors and the weighted sum method is used in the objective function for overall multi-objective optimization. A bicycle platform configuration will be used as a case study to demonstrate the application of the model. The relationship between commonality of the platform and sustainability performance is analyzed.