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Sökning: db:Swepub > Övrigt vetenskapligt/konstnärligt > Mälardalens universitet > (2005-2009) > Norström Christer

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1.
  • Andersson, Johan, et al. (författare)
  • A Framework for Analysis of Timing and Resource Utilization targeting Complex Embedded Systems
  • 2006
  • Ingår i: ARTES - A network for Real-Time research and graduate Education in Sweden 1997 - 2006. - Uppsala : Department of Information Technology. - 9150618598 ; , s. 297-329
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • A problem in common of many complex software systems embedded in industrialproducts is the absence of analyzability as formal models of the systembehavior does not exist. When performing maintenance of such systems it ishard to predict how changes will impact specific system properties related totiming and resource utilization and there is therefore a significant risk of runninginto problems with unexpected side-effects of the changes made, whichincreases development time required and costs.In this paper we present the ART Framework, a set of methods and toolsthat enable behavior impact analysis for existing industrial real-time systems.The ART Framework enables developers of complex software systems to identifyproblematic side-effects of a proposed design before vast resources havebeen invested in implementation and testing. This reduces the risk of expensiveand time-consuming problems discovered late in a development projectand also reduces the risk releasing software containing latent critical errors.
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2.
  • Carlson, Jan, 1976- (författare)
  • Event Pattern Detection for Embedded Systems
  • 2007
  • 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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3.
  • Fröberg, Joakim, 1970- (författare)
  • Engineering Automotive Electronic Systems: Decision Support for Successful Integration
  • 2007
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The electronic system of a modern vehicle is essential to achieve a successful automotive product. Vehicle development is performed by integrating components that include embedded electronics from several suppliers.This thesis present results on the subject of integration of automotive electronic systems. Our studies aim at providing knowledge on how to integrate automotive electronic systems successfully in a setting where vehicles are developed based on existing platforms. We focus on early phases of automotive electronic system development and in particular on the decisions taken in integration of electronic sub-systems. The contribution is the presented support for making decisions to successfully integrate electronic systems for modern vehicles. The contribution includes an overview of driving factors of automotive electronics system design, a validated set of success practices for the integration of electronic components, and the proposal and demonstration of a decision model. The influential factors and the validated set of practices stems from case studies of products and projects while the proposed decision model is a result of combining two general models for architecture analysis and decision making, ATAM and AHP.We demonstrate that choices in strategy and design preceding integration are central to achieve a successful integration. Our studies show that problems arise from omitted strategy decisions and we provide a checklist for decision making in the areas; functionality, platform, integration design, and assigning responsibilities. We provide a recommendation that we validate in a multiple cases study where fulfillment of recommendations is demonstrated to affect project success in integration projects.The potential gain for OEMs using our results lies in achieving more solid foundations for design decisions. Designers and managers could potentially find central decisions on integration strategy early that, if omitted, could cause delays. Thus, applying the result could avoid pitfalls and enable successful integration projects.
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4.
  • Hänninen, Kaj, 1970- (författare)
  • Introducing a Memory Efficient Execution Model in a Tool-Suite for Real-Time Systems
  • 2006
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis shows how development of embedded real-time systems can be made more efficient by introduction of an memory efficient execution model in a commercial development suite. To identify the need of additional support for execution models in development tools, the thesis investigate by a series of interviews, the common requirements in development of industrial embedded real-time systems. The results indicate that there exist functionality in industrial systems that could be more efficiently implemented in other execution models than the currently supported ones. The thesis then presents how use of multiple execution models (hybrid scheduling) can reduce processor utilization in real-world applications. Furthermore, the thesis presents an integration of an memory efficient execution model in an industrially used real-time operating system. In addition, the thesis describes an efficient technique to analyze memory consumptions of functionality executing under the introduced execution model.Embedded computers play an important role in peoples everyday life. Nowadays, we can find computers in product such as microwave ovens, washing machines, DVD players, cellular phones and cars, to mention a few examples. For example, a modern car may have more than 70 embedded control units handling functionality such as airbags, anti-lock braking, traction control etc. In addition, there is a clear trend indicating that the amount of computer controlled functionality in products will continue to increase. Many of today’s embedded systems are resource constrained and the software for them is developed for a few execution models. Even though researchers has proposed a numerous number of different execution models for embedded real-time systems, in practice however, only a few of the proposed execution models are supported in industrial development tools. This implies that developers often force fit functionality to be executed under these models, resulting in poor resource utilization and increasing complexity in software.
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5.
  • Land, Rikard, 1975- (författare)
  • Software Systems In-House Integration : Observations and Guidelines Concerning Architecture and Process
  • 2006
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Software evolution is a crucial activity for software organizations. A specifc type of software evolution is the integration of previously isolated systems. The need for integration is often a consequence of different organizational changes, including merging of previously separate organizations. One goal of software integration is to increase the value to users of several systems by combining their functionality, another is to reduce functionality overlap. If the systems are completely owned and controlled in-house, there is an additional advantage in rationalizing the use of internal resources by decreasing the amount of software with essentially the same purpose. Despite in-house integration being common, this topic has received little attention from researchers. This thesis contributes to an increasing understanding of the problems associated with in-house integration and provides guidelines to the more efficient utilization of the existing systems and the personnel.In the thesis, we combine two perspectives: software architecture and processes. The perspective of software architecture is used to show how compatibility analysis and development of integration alternatives can be performed rapidly at a high level of abstraction. The software process perspective has led to the identification of important characteristics and practices of the integration process. The guidelines provided in the thesis will help those performing future in-house integration to make well-founded decisions timely and efficiently.The contributions are based on several integration projects in industry, which have been studied systematically in order to collect, evaluate and generalize their experiences.
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6.
  • Lindgren, Markus, 1975- (författare)
  • Towards a Capability Model for Release Planning of Software Intensive Systems
  • 2008
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Release planning is an early product development activity concerned with deciding which features and quality improvements that should be pursued in product development projects, i.e., it is an activity which in large parts decide how the development budget of a company is allocated. This thesis investigates release planning for long-lived software intensivesystems; systems which contain software, electronics, and mechanics, and which have a life-cycle of 10-20 years. In performing release planning for these kind of systems, the existing system, including its architecture, often represent a large investment which has impact on which features and quality improvements that are cost-efficient to include in a future release. However, in industry today, little attention is given to the existing system during planning, resulting in decisions being based on uncertain information, and thereby increasing the risk of problems in the development projects. This thesis is based on a multiple case study involving seven industrialcompanies developing and producing long-lived software intensive systems. There are several contributions in this thesis, aimed at understanding and improving the release planning process: (1) validation of previous research related to key-aspects for release planning including identification of short- and long-term planning as a new key-aspect; (2) the capture of state-of-the-practice for release planning in industry; (3) a proposal for a capability model for release planning, which can be used to assess the capabilities of a company's release planning process, but also for identifying process improvement possibilities; and (4) a process for how to decide the balance between investments in features and quality improvements, developed based on the practices used at two of the most capable companies in the study. Finding such a balance is important since adding new features may attract new potential customers, while improving the quality for existing customers can reduce costs of poor quality.  
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7.
  • Nolte, Thomas, 1977- (författare)
  • Share-Driven Scheduling of Embedded Networks
  • 2006
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Many products are built from more or less independently developed subsystems. For instance, a car consists of subsystems for transmission, braking, suspension, etc. These subsystems are frequently controlled by an embedded computer system. In the automotive industry, as well as in other application domains, there is currently a trend from an approach where subsystems have dedicated computer hardware and other resources (a federated approach) to an approach where subsystems share hardware and other resources (an integrated approach). This is motivated by a strong pressure to reduce product cost, at the same time as an increasing number of subsystems are being introduced.When integrating subsystems, it is desirable that guarantees valid before integration are also valid after integration, since this would eliminate the need for costly reverifications. The computer network is a resource that is typically shared among all subsystems. Hence, a central issue when integrating subsystems is to provide an efficient scheduling of message transmissions on the network. There are essentially three families of schedulers that can be used: priority-driven schedulers that assign priorities to messages, time-driven schedulers that assign specific time-slots for transmission of specific messages, and share-driven schedulers that assign shares of the available network capacity to groups of messages.This thesis presents a framework for share-driven scheduling, to be implemented and used in embedded networks, with the aim to facilitate subsystem integration by reducing the risk of interference between subsystems. The framework is applied in the automotive domain.The initial parts of the thesis give an overview of systems, subsystems and network technologies found and used in the automotive domain. Then, the share-driven scheduling framework is presented, analytically investigated and proven, as well as evaluated in a simulation study. Finally it is shown how the framework is to be configured and used in the context of subsystem integration. The results show that the framework allows for flexible and efficient scheduling of messages with real-time constraints, facilitating integration of subsystems from a network point of view.
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8.
  • Norström, Christer, et al. (författare)
  • Special section on factory communication systems
  • 2005
  • Ingår i: IEEE Transactions on Industrial Informatics. - 1551-3203 .- 1941-0050. ; 1:3, s. 149-150
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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9.
  • Nyström, Dag, 1969- (författare)
  • Data Management in Vehicle Control-Systems
  • 2005
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • As the complexity of vehicle control-systems increases, the amount of information that these systems are intended to handle also increases. This thesis provides concepts relating to real-time database management systems to be used in such control-systems. By integrating a real-time database management system into a vehicle control-system, data management on a higher level of abstraction can be achieved. Current database management concepts are not sufficient for use in vehicles, and new concepts are necessary. A case-study at Volvo Construction Equipment Components AB in Eskilstuna, Sweden presented in this thesis, together with a survey of existing database platforms confirms this. The thesis specifically addresses data access issues by introducing; (i) a data access method, denoted database pointers, which enables data in a real-time database management system to be accessed efficiently. Database pointers, which resemble regular pointers variables, permit individual data elements in the database to be directly pointed out, without risking a violation of the database integrity. (ii) two concurrency-control algorithms, denoted 2V-DBP and 2V-DBP-SNAP which enable critical (hard real-time) and non-critical (soft real-time) data accesses to co-exist, without blocking of the hard real-time data accesses or risking unnecessary abortions of soft real-time data accesses. The thesis shows that 2V-DBP significantly outperforms a standard real-time concurrency control algorithm both with respect to lower response-times and minimized abortions. (iii) two concepts, denoted substitution and subscription queries that enable service- and diagnostics-tools to stimulate and monitor a control-system during run-time. The concepts presented in this thesis form a basis on which a data management concept suitable for embedded real-time systems, such as vehicle control-systems, can be built.
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10.
  • Nyström, Dag, et al. (författare)
  • Snapshots in Real-Time Database using Database Pointer Transactions
  • 2005
  • Ingår i: Proceedings - 11th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications. - 9780769523460 ; , s. 343-349
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • We present 2V-DBP-SNAP an algorithm that allows hard real-time tasks in an embedded real-time control system to read a snapshot of a number of data elements in a real-time database. Furthermore, 2V-DBP-SNAP allows these data elements to be shared with soft real-time tasks, which access them using a database query language, and with other hard real-time tasks that use database pointers. 2V-DBP-SNAP allows temporal behavior and memory consumption to be accurately predicted. Introducing snapshot transactions is beneficial for embedded control-systems, such as for engine control in an automotive system, since a snapshot of the state of the environment can be collected, e.g., the state of all cylinders in the engine. 2V-DBP-SNAP is lightweight and predictable, both with respect to computational and memory overhead, and is therefore highly suited for resource constrained systems.
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