During the last decade the gap between software modeling and performancemodeling has been closing. For example, UML annotations have been developed to enable the transformation of UML software models to performance models, thereby making performance modeling more accessible. However, as of yet few of these tools are ready for industrial application. In this thesis we explorer the current state of performance modeling tooling, the selection of a performance modeling tool for industrial application is described and a performance modeling case study on one of ABB's remote diagnostics systems (RDS) is presented. The case study shows the search for the best architectural alternative during a multi-million dollar redesign project of the ASP.Net web services based RDS back-end. The performance model is integrated with a cost model to provide valuable decision support for the construction of an architectural roadmap. Despite our success we suggest that the stability of software performance modeling tooling and the semantic gap between performance modeling and software architecture concepts are major hurdles to widespread industrial adaptation. Future work may use the experiences recorded in this thesis to continue improvement of performance modeling processes and tools for industrial use.

The thesis work is conducted in the division of computer engineering at thedepartment of electrical engineering in Linköping University. During the thesiswork, a configurable Direct Memory Access (DMA) controller was designed andimplemented. The DMA controller runs at 200MHz under 65nm digital CMOS technology. The estimated gate count is 26595. The DMA controller has two address generators and can provide two clocksources. It can thus handle data read and write simultaneously. There are 16channels built in the DMA controller, the data width can be 16-bit, 32-bit and64-bit. The DMA controller supports 2D data access by configuring its intelligentlinking table. The DMA is designed for advanced DSP applications and it is notdedicated for cache which has a fixed priority.

The research presented in this thesis investigates the concept of sustainability in relation to mobile learning initiatives. Sustainability is seen as a key concept for mobile learning to gain acceptance. In linking sustainability to scalability, a term used to describe how well something can grow to suit an increasing complexity, a representation of this process is provided. In this thesis, this process is called ``the quest for equilibrium.'' A study was conducted of an actual mobile learning initiative that involved introducing podcasts as a supplement to traditional lectures in higher education. In following this initiative, thorough data gathering was conducted, utilizing the process of iterative cycles that characterizes the action research approach. In accordance, a literature survey was conducted, whereby leading publications in mobile learning were classified and analyzed according to the following criteria: Reflections, Frameworks, Scalability, and Sustainability. As the mobile learning system evolved from idea to an actual empirical study, trying to understand this process became important. The insights gained during this research were used to develop a conceptual model that is based on the notion that the two concepts of Scalability and Sustainability can be linked to each other. This conceptual model is presented describing how a mobile learning system evolves, from Idea, to Experiment, to Project, to Release. Further, each of the stages in this evolution is described by using four areas of concern: Technology, Learning, Social, and Organization. Using the experience from a specific mobile learning initiative to define a conceptual model that then is used to describe the same initiative, was a way to bring together practice, theory, and research, thus provide reliable evidence for the model itself. The conceptual model can serve as a thinking tool for mobile learning practitioners, to help address the complexity involved when undertaking new efforts and initiatives in this field.

Context. Testing of web applications is an important task, as it ensures the functionality and quality of web applications. The quality of web application comes under non-functional testing. There are many quality attributes such as performance, scalability, reliability, usability, accessibility and security. Among these attributes, PSR is the most important and commonly used attributes considered in practice. However, there are very few empirical studies conducted on these three attributes. Objectives. The purpose of this study is to identify metrics and tools that are available for testing these three attributes. And also to identify the challenges faced while testing these attributes both from literature and practice. Methods. In this research, a systematic mapping study was conducted in order to collect information regarding the metrics, tools, challenges and mitigations related to PSR attributes. The required information is gathered by searching in five scientific databases. We also conducted a case study to identify the metrics, tools and challenges of the PSR attributes in practice. The case study is conducted at Ericsson, India where eight subjects were interviewed. And four subjects working in other companies (in India) were also interviewed in order to validate the results obtained from the case company. In addition to this, few documents of previous projects from the case company are collected for data triangulation. Results. A total of 69 metrics, 54 tools and 18 challenges are identified from systematic mapping study. And 30 metrics, 18 tools and 13 challenges are identified from interviews. Data is also collected through documents and a total of 16 metrics, 4 tools and 3 challenges were identified from these documents. We formed a list based on the analysis of data that is related to tools, metrics and challenges. Conclusions. We found that metrics available from literature are overlapping with metrics that are used in practice. However, tools found in literature are overlapping only to some extent with practice. The main reason for this deviation is because of the limitations that are identified for the tools, which lead to the development of their own in-house tool by the case company. We also found that challenges are partially overlapped between state of art and practice. We are unable to collect mitigations for all these challenges from literature and hence there is a need for further research to be done. Among the PSR attributes, most of the literature is available on performance attribute and most of the interviewees are comfortable to answer the questions related to performance attribute. Thus, we conclude there is a lack of empirical research related to scalability and reliability attributes. As of now, our research is dealing with PSR attributes in particular and there is a scope for further research in this area. It can be implemented on the other quality attributes and the research can be done in a larger scale (considering more number of companies).

No description available.

Le travail présenté dans ce mémoire a pour objectif le développement d'une nouvelle architecture pour les systèmes de vidéosurveillance. Tout d'abord, une étude bibliographique nous a conduit à classer les systèmes existants selon le niveau de leurs applications qui dépend directement des fonctions analytiques exécutées. Nous avons également constaté que les systèmes habituels traitent toutes les données enregistrées alors que réellement une faible partie des scènes sont utiles pour l'analyse. Ainsi, nous avons étendu l'architecture ordinaire des systèmes de surveillance par une phase de pré-analyse qui extrait et simplifie les régions d'intérêt en conservant les caractéristiques importantes. Deux méthodes différentes pour la pré-analyse dans le contexte de la vidéosurveillance ont été proposées : une méthode de filtrage spatio-temporel et une technique de modélisation des objets en mouvement. Nous avons contribué, aussi, par l'introduction du concept de la scalabilité orientée vers l'application à travers une architecture multi-niveaux applicatifs pour les systèmes de surveillance. Les différents niveaux d'applications des systèmes de vidéosurveillance peuvent être atteints incrémentalement pour répondre aux besoins progressifs de l'utilisateur final. Un exemple de système de vidéosurveillance respectant cette architecture et utilisant nos méthodes de pré-analyse est proposé. / The work presented in this thesis aims to develop a new architecture for video surveillance systems. Firstly, a literature review has led to classify the existing systems based on their applications level which dependents directly on the performed analytical functions. We, also, noticed that the usual systems treat all captured data while, actually, a small part of the scenes are useful for analysis. Hence, we extended the common architecture of surveillance systems with a pre-analysis phase that extracts and simplifies the regions of interest with keeping the important characteristics. Two different methods for preanalysis were proposed : a spatio-temporal filtering and a modeling technique for moving objects. We contributed, too, by introducing the concept of application-oriented scalability through a multi-level application architecture for surveillance systems. The different applications levels can be reached incrementally to meet the progressive needs of the enduser. An example of video surveillance system respecting this architecture and using the preanalysis methods was proposed.

This thesis deals with NoSQL database performance issue. The aim of the paper is to compare most common prototypes of distributed database systems with emphasis on performance and scalability. Yahoo! Cloud Serving Benchmark (YCSB) is used to accomplish the aforementioned aim. The YCSB tool allows performance testing through performance indicators like throughput or response time. It is followed by a thorough explanation of how to work with this tool, which gives readers an opportunity to test performance or do a performance comparison of other distributed database systems than of those described in this thesis. It also helps readers to be able to create testing environment and apply the testing method which has been listed in this thesis should they need it. This paper can be used as a help when making an arduous choice for a specific system from a wide variety of NoSQL database systems for intended solution.

Advances in integrated circuit technology continue to provide more and more transistors on a chip. Computer architects are faced with the challenge of finding the best way to translate these resources into high performance. The challenge in the design of next generation CPU (central processing unit) lies not on trying to use up the silicon area, but on finding smart ways to make use of the wealth of transistors now available. In addition, the next generation architecture should offer high throughout performance, scalability, modularity, and low energy consumption, instead of an architecture that is suitable for only one class of applications or users, or only emphasize faster clock rate. A program exhibits different types of parallelism: instruction level parallelism (ILP), thread level parallelism (TLP), or data level parallelism (DLP). Likewise, architectures can be designed to exploit one or more of these types of parallelism. It is generally not possible to design architectures that can take advantage of all three types of parallelism without using very complex hardware structures and complex compiler optimizations. We present the state-of-art architecture SDF (scheduled data flowed) which explores the TLP parallelism as much as that is supplied by that application. We implement a SDF single-chip multiprocessor constructed from simpler processors and execute the automatically parallelizing application on the single-chip multiprocessor. SDF has many desirable features such as high throughput, scalability, and low power consumption, which meet the requirements of the next generation of CPU design. Compared with superscalar, VLIW (very long instruction word), and SMT (simultaneous multithreading), the experiment results show that for application with very little parallelism SDF is comparable to other architectures, for applications with large amounts of parallelism SDF outperforms other architectures.

Veículos Aéreos não tripulados (VANTs) vêm sendo cada vez mais utilizados em diversos países, tanto na área militar como na civil. O cenário considerado nesse estudo é o de um VANT realizando captura de vídeo em tempo real, transmitindo-o a uma base terrestre por meio de rede sem fio. O problema consiste no fato de não ser possível garantir uma taxa de transmissão contínua, com banda estável. Isso ocorre devido a fatores como a velocidade da aeronave (da ordem centenas de km/h), irregularidades de terreno (impedindo a linha de visada do enlace de transmissão), ou do clima, como tempestades que podem interferir na transmissão da RF. Por fim, os movimentos que o VANT pode realizar no vôo (Rolagem, Arfagem ou Guinada) podem prejudicar a disponibilidade do link. Dessa forma, é necessário que seja realizada adaptação de vídeo de acordo com a banda disponível. Assim, quando a qualidade do enlace for degradada, deverá ser realizada uma redução no tamanho do vídeo, evitando a interrupção na transmissão. Por outro lado, a adaptação também deverá fazer com que a banda disponível seja utilizada, evitando o envio de vídeos com qualidade inferior à que seria possível para determinado valor de largura de banda. Nesse trabalho será considerada a faixa de valores de largura de banda de 8 Mbps até zero. Para realizar a adaptação será utilizado o padrão H.264/AVC com codificação escalável / Unmanned Aerial Vehicles (UAVs) are being increasingly used in several countries, both in the military and civilian areas. In this study we consider an UAV equipped with a camera, capturing video for a real-time transmission to a ground-base using wireless network. The problem is that its not possible to ensure a continuous transmission rate, with stable bandwidth. That occurs due to factors like the speed of the aircraft, irregularities of terrain, or the weather (as storms, heat and fog, for instance, can interfere with RF transmission). Finally, the movements that the UAV can perform in flight (Roll, pitch and yaw) can impair link availability. Thus, it is necessary to perform an adaptation of video according to the available bandwidth. When the link quality is degraded, a reduction in the resolution of the video must be performed , avoiding interruption of the transmission. Additionally, adaptation must also provide that all the available bandwidth is used, avoiding sending the video with lower quality that would be possible for a given value bandwidth. In this work we propose a system which can vary the total amount of data being transmitted, by adjusting the compression parameters of the video. We manage to produce a system which uses the range from 8 Mbps up to zero. We use the H.264/AVC Codec, with scalable video coding

Smart City technologies emerge as a potential solution to tackle common problems in large urban centers by using city resources efficiently and providing quality services for citizens. Despite the various advances in middleware technologies to support future smart cities, there are yet no widely accepted platforms. Most of the existing solutions do not provide the required flexibility to be shared across cities. Moreover, the extensive use and development of non-open-source software leads to interoperability issues and limits the collaboration among R&D groups. Our research explores the use of a microservices architecture to address key practical challenges in smart city platforms. More specifically, we are concerned with the impact of microservices on addressing the key non-functional requirements to enable the development of smart cities such as supporting different scalability demands and providing a flexible architecture which can easily evolve over time. To this end, we are developing InterSCity, a microservice-based open source smart city platform that aims at supporting the development of sophisticated, cross- domain applications and services. Our early experience shows that microservices can be properly used as building blocks to achieve a loosely coupled, flexible architecture. Experimental results point towards the applicability of our approach in the context of smart cities since the platform can support multiple scalability demands. We expect to enable collaborative, novel smart city research, development, and deployment initiatives through the InterSCity platform. The full validation of the platform will be conducted using different smart city scenarios and workloads. Future work comprises the ongoing design and development effort on data processing services as well as more comprehensive evaluation of the proposed platform through scalability experiments. / As tecnologias de Cidades Inteligentes surgem como uma potencial solução para lidar com problemas comuns em grandes centros urbanos, utilizando os recursos da cidade de maneira eficiente e fornecendo serviços de qualidade para os cidadãos. Apesar dos vários avanços nas tecnologias de middleware para suporte às cidades inteligentes do futuro, ainda não existem plataformas amplamente aceitas. A maioria das soluções existentes não oferece a flexibilidade necessária para ser compartilhada entre as cidades. Além disso, o vasto uso e desenvolvimento de software proprietário levam a problemas de interoperabilidade e limitam a colaboração entre grupos de P&D. Nesta dissertação, exploramos uso de uma arquitetura de microsserviços para abordar os principais desafios práticos em plataformas de cidades inteligentes. Mais especificamente, estamos preocupados com o impacto dos microsserviços sobre requisitos não-funcionais para permitir o desenvolvimento de cidades inteligentes, tais como o suporte a diferentes demandas de escalabilidade e o fornecimento de uma arquitetura flexível que pode evoluir facilmente. Para esse fim, criamos a InterSCity, uma plataforma para cidades inteligentes de código aberto baseada em microsserviços que visa apoiar o desenvolvimento de aplicativos e serviços sofisticados em múltiplos domínios. Nossa experiência inicial mostra que os microsserviços podem ser usados adequadamente como blocos de construção para obter uma arquitetura flexível e fracamente acoplada. Resultados experimentais apontam para a aplicabilidade de nossa abordagem no contexto de cidades inteligentes, já que a plataforma pode suportar diferentes demandas de escalabilidade. Esperamos permitir pesquisas colaborativas e inovadoras em cidades inteligentes, assim como o desenvolvimento e iniciativas de implantações reais através da plataforma InterSCity. A validação completa da plataforma será realizada usando diferentes cenários de cidades inteligentes e cargas de trabalho. Os trabalhos futuros compreendem o esforço contínuo de projetar e desenvolver novos serviços de processamento de dados, bem como a realização de avaliações mais abrangentes da plataforma proposta por meio de experimentos de escalabilidade.