| 1. |
- Bohlin, Markus, et al.
(författare)
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Safe Shared Stack Bounds in Systems with Offsets and Precedences
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents two novel methods to bound the stack memory used in preemptive, shared stack, real-time systems. The first method is based on branch-and-bound search for possible preemption patterns, and the second one approximates the first in polynomial time. The work extends previous methods by considering a more general taskmodel, in which all tasks can share the same stack. In addition, the new methods account for precedence and offset relations. Thus, the methods give tight bounds for a large set of realistic systems. The methods have been implemented and a comprehensive evaluation, comparing our new methods against each other and against existing methods, is presented. The evaluation shows that our exact method can significantly reduce the amount of stack memory needed. In our simulations, a decrease in the order of 40% was typical, with a runtime in the order of seconds. Our polynomial approximation consequently yields about 20% higher bound than the exact method.
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| 2. |
- Bosch, Jan, 1967, et al.
(författare)
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Accelerating digital transformation: 10 years of software center
- 2022
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This book celebrates the 10-year anniversary of Software Center (a collaboration between 18 European companies and five Swedish universities) by presenting some of the most impactful and relevant journal or conference papers that researchers in the center have published over the last decade. The book is organized around the five themes around which research in Software Center is organized, i.e. Continuous Delivery, Continuous Architecture, Metrics, Customer Data and Ecosystems Driven Development, and AI Engineering. The focus of the Continuous Delivery theme is to help companies to continuously build high quality products with the right degree of automation. The Continuous Architecture theme addresses challenges that arise when balancing the need for architectural quality and more agile ways of working with shorter development cycles. The Metrics theme studies and provides insight to understand, monitor and improve software processes, products and organizations. The fourth theme, Customer Data and Ecosystem Driven Development, helps companies make sense of the vast amounts of data that are continuously collected from products in the field. Eventually, the theme of AI Engineering addresses the challenge that many companies struggle with in terms of deploying machine- and deep-learning models in industrial contexts with production quality. Each theme has its own part in the book and each part has an introduction chapter and then a carefully selected reprint of the most important papers from that theme. This book mainly aims at researchers and advanced professionals in the areas of software engineering who would like to get an overview about the achievement made in various topics relevant for industrial large-scale software development and management - and to see how research benefits from a close cooperation between industry and academia.
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| 3. |
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| 4. |
- Bures, Tomas, et al.
(författare)
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Progress Component Model Reference Manual - version 0.5
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes the component model developed within PROGRESS. In addition to defining the syntax and semantics, it also gives some background and motivation, and describes how this work relates to the overall PROGRESS vision and to the work in other areas of the project.
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| 5. |
- Bures, Tomas, et al.
(författare)
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Towards Component Modelling of Embedded Systems in the Vehicular Domain
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The complexity of software and electronics in vehicular systems has increased significantly over last few years - up to the point when it is difficult to manage it with existing development methods. In this paper we aim at using components for managing the complexity in vehicular systems. Compared to other approaches, the distinguishing feature of our work is using and benefiting from components throughout the whole development process (from early design to development and deployment). Based on the elaboration of the specifics of vehicular systems (resource constraints, real-time requirements, hard demands on reliability), the paper identifies concerns that need to be addressed by a component model for this domain. It also outlines basic features and characteristics of such a component model and discusses how relevant existing formalisms and component models relate to it and how they could be reused within the proposed approach.
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| 6. |
- Campeanu, Gabriel, 1982-
(författare)
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GPU-aware Component-based Development for Embedded Systems
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nowadays, more and more embedded systems are equipped with e.g., various sensors that produce large amount of data. One of the challenges of traditional (CPU-based) embedded systems is to process this considerable amount of data such that it produces the appropriate performance level demanded by embedded applications. A solution comes from the usage of a specialized processing unit such as Graphics Processing Unit (GPU). A GPU can process large amount of data thanks to its parallel processing architecture, delivering an im- proved performance outcome compared to CPU. A characteristic of the GPU is that it cannot work alone; the CPU must trigger all its activities. Today, taking advantage of the latest technology breakthrough, we can benefit of the GPU technology in the context of embedded systems by using heterogeneous CPU-GPU embedded systems.Component-based development has demonstrated to be a promising methology in handling software complexity. Through component models, which describe the component specification and their interaction, the methodology has been successfully used in embedded system domain. The existing component models, designed to handle CPU-based embedded systems, face challenges in developing embedded systems with GPU capabilities. For example, current so- lutions realize the communication between components with GPU capabilities via the RAM system. This introduces an undesired overhead that negatively affects the system performance.This Licentiate presents methods and techniques that address the component- based development of embedded systems with GPU capabilities. More concretely, we provide means for component models to explicitly address the GPU-aware component-based development by using specific artifacts. For example, the overhead introduced by the traditional way of communicating via RAM is reduced by inserting automatically generated adapters that facilitate a direct component communication over the GPU memory.Another contribution of the thesis is a component allocation method over the system hardware. The proposed solution offers alternative options in opti- mizing the total system performance and balancing various system properties (e.g., memory usage, GPU load). For the validation part of our proposed solutions, we use an underwater robot demonstrator equipped with GPU hardware.
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| 7. |
- Campeanu, Gabriel, 1982-
(författare)
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GPU Support for Component-based Development of Embedded Systems
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One pressing challenge of many modern embedded systems is to successfully deal with the considerable amount of data that originates from the interaction with the environment. A recent solution comes from the use of GPUs. Equipped with a parallel execution model, the GPU excels in parallel processing applications, providing an improved performance compared to the CPU.Another trend in the embedded systems domain is the use of component-based development. This software engineering paradigm that promotes construction of applications through the composition of software components, has been successfully used in the development of embedded systems. However, the existing approaches provide no specific support to develop embedded systems with GPUs. As a result, components with GPU capability need to encapsulate all the required GPU information in order to be successfully executed by the GPU. This leads to component specialization to specific platforms, hence drastically impeding component reusability.Our main goal is to facilitate component-based development of embedded systems with GPUs. We introduce the concept of flexible component which increases the flexibility to design embedded systems with GPUs, by allowing the system developer to decided where to place the component, i.e., either on the CPU or GPU. Furthermore, we provide means to automatically generate the required information for flexible components corresponding to their hardware placement, and to improve component communication. Through the introduced support, components with GPU capability are platform-independent, being capable to be executed on a large variety of hardware (i.e., platforms with different GPU characteristics). Furthermore, an optimization step is introduced, which groups connected flexible components into single entities that behave as regular components. Dealing with components that can be executed either by the CPU or GPU, we also introduce an allocation optimization method. The proposed solution, implemented using a mathematical solver, offers alternative options in optimizing particular system goals (e.g., memory and energy usage).
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| 8. |
- Carlson, Jan
(författare)
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An intuitive and resource-efficient event detection algebra
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In reactive systems, execution is driven by external events to which the system should respond with appropriate actions. Such events can be simple, but systems are often supposed to react to sophisticated situations involving a number of simpel events occurring in accordance with some pattern. A systematic approach to handle this type of systems is to separate the mechanism for detecting composite events from the rest of the application logic. A detection mechanism listens for simple event occurrences and notifies the application when one of the complex event patterns of interest occur. The event detection mechanism can for example be based on an event algebra, i.e., expressions that correspond to the event patterns of interest are built from simple events and operators from the algebra. This thesis presents a novel event algebra with two important characteristics: It complies with algebraic laws that intuitively ought to hold for the operators of the algebra, and for a large class of expressions the detection can be correctly performed with limited resources in terms of memory and time. In addition to the declarative algebra semantics, we present an imperative detection algorithm and show that it correctly implements the algebra. This algorithm is analysed with respect to memory requirements and execution time complexity. To increase the efficiency of the algebra, we also present a semantic-preserving transformation scheme by which many expressions can be transformed to meet criteria under which limited resource requirements are guaranteed. Finally, we present a prototype implementation that combines the algebra with the event system in Java.
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| 9. |
- Carlson, Jan, 1976-
(författare)
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Event Pattern Detection for Embedded Systems
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Events play an important role in many computer systems, from small reactive embedded applications to large distributed systems. Many applications react to events generated by a graphical user interface or by external sensors that monitor the system environment, and other systems use events for communication and synchronisation between independent subsystems. In some applications, however, individual event occurrences are not the main point of concern. Instead, the system should respond to certain event patterns, such as "the start button being pushed, followed by a temperature alarm within two seconds". One way to specify such event patterns is by means of an event algebra with operators for combining the simple events of a system into specifications of complex patterns.This thesis presents an event algebra with two important characteristics. First, it complies with a number of algebraic laws, which shows that the algebra operators behave as expected. Second, any pattern represented by an expression in this algebra can be efficiently detected with bounded resources in terms of memory and time, which is particularly important when event pattern detection is used in embedded systems, where resource efficiency and predictability are crucial.In addition to the formal algebra semantics and an efficient detection algorithm, the thesis describes how event pattern detection can be used in real-time systems without support from the underlying operating system, and presents schedulability theory for such systems. It also describes how the event algebra can be combined with a component model for embedded system, to support high level design of systems that react to event patterns.
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| 10. |
- Carlson, Jan, et al.
(författare)
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Feasibility of migrating analysis and synthesis mechanisms from ProCom to IEC 61499
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report presents the initial results from the Assist project at Mälardalen University, funded by the ABB Software Research Grant Program. The project aims to bridge the gap between recent academic research achievements in the area of control- and model based development of embedded systems, and concrete industrial needs and state of practice in this domain. Concretely, the focus of the project is to investigate how novel timing analysis and code synthesis techniques developed in the context of ProCom, an academic component model for embedded systems, can be extended and adapted in order to be applicable to IEC 61499.
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