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  • 1.
    Aarts, Marcel
    Mälardalen University, School of Innovation, Design and Engineering.
    Using Kinect to interact with presentation software2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Imagination Studios is a company specialized in motion capturing and animation. Part of their daily business is working at trade shows where they have a booth to keep close contact with existing customers and also to find new ones. However, usually only two to three people will be working at the booth, and frequently, these people will be in meetings with potential customers. During a time like this, nobody is free to attend to other people checking out the booth. This can result in a potential loss of a new customer. This project seeks a way to alleviate that problem.The idea behind this project was to create an application that trade show visitors can interact with in a playful and innovative way while also giving them a feel of what Imagination Studios is all about while looking for information about the company. To do this it was decided to let users interact with the system by using a Microsoft Kinect. The Kinect allows for easy implementation of a user interface based on motion capturing while also being very cost effective. A new user interface was to be designed as well, without copying already existing solutions and without simply expanding a traditional UI with new elements. To achieve this several design sketches were made, and the most interesting ones were then turned into storyboards. These were then used to decide on the final design, which was then elaborated on by use of video sketches and a collage in Adobe Photoshop.Several tools were used during the actual implementation. For the actual visualization and graphical design, the Unreal Engine 3 in combination with UDK was decided upon. To connect Kinect and Unreal Engine 3, a third party addon called NIUI which makes use of the open source SDK OpenNI was used. For ease of debugging and programming in Unrealscript, the programming language used by the Unreal Engine 3, an addon for Microsoft Visual Studio 2010 called nFringe (Pixel Mine, Inc., 2010) was used.

  • 2.
    Abdullah, Syed Md Jakaria
    Mälardalen University, School of Innovation, Design and Engineering.
    Virtual Clustered-based Multiprocessor Scheduling in Linux Kernel2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recent advancements of multiprocessor architectures have led to increasing use of multiprocessors in real-time embedded systems. The two most popular real-time scheduling approaches in multiprocessors are global and partitioned scheduling. Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation duringrun-time and applying hierarchical scheduling to ensure temporal isolation between different software components. Over the years, the study of virtual clustered-based multiprocessor scheduling has been limited to theoretical analysis. In this thesis, we implemented a Virtual-Clustered Hierarchical Scheduling Framework (VC-HSF) in Linux without modifying the base Linux kernel. This work includes complete design, implementation and experimentation of this framework in a multiprocessor platform. Our main contributions are twofold: (i) to the best of our knowledge, our work is the first implementation of any virtual-clustered real-time multiprocessor scheduling in an operating system, (ii) our design and implementation gives practical insights about challenges of implementing any virtual-clustered algorithms for real-time scheduling.

  • 3.
    Achrenius, William
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Bergman Törnkvist, Martin
    Mälardalen University, School of Innovation, Design and Engineering.
    GRAPH GENERATION ALGORITHMS FOR THE GRADE DECISION CANVAS2018Independent thesis Basic level (degree of Bachelor), 12 HE creditsStudent thesis
    Abstract [en]

    Development in the field of software architecture, from the early days in the mid-80’s, has been significant. From purely technical descriptions to decision based architectural knowledge, software architecture has seen fundamental changes to its methodologies and techniques. Architectural knowledge is a resource that is managed and stored by companies, this resource is valuable because it can be reused and analysed to improve future development. Companies today are interested in the reasoning behind the software architecture. This reasoning is mainly formulated through the architectural decisions made during development. For architectural decisions to be easier to analyse they need to be stored in a way that enables use of common analytical tools so that comparisons between decisions are consistent and relevant. Additionally, it is also important to have enough data, which leads us to the problem that, preferably, all the individual architectural knowledge cases must be structured and stored. To do this we present a tool that uses graph generation algorithms to generate architectural knowledge as graphs based on an architectural decision canvas called GRADE. This enables multiple decision cases to be encoded through graphs that can be used to analyse relationships and balances between different architectural knowledge elements represented through nodes and edges within a graph.

  • 4.
    Afshar, Sara
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lock-Based Resource Sharing in Real-Time Multiprocessor Platforms2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Embedded systems are typically resource constrained, i.e., resources such as processors, I/O devices, shared buffers or shared memory can be limited for tasks in the system. Therefore, techniques that enable an efficient usage of such resources are of great importance.

    In the industry, typically large and complex software systems are divided into smaller parts (applications) where each part is developed independently. Migration towards multiprocessor platforms has become inevitable from an industrial perspective. Due to such migration and to efficient use of system resources, these applications eventually may be integrated on a shared multiprocessor platform. In order to facilitate the integration phase of the applications on a shared platform, the timing and resource requirements of each application can be provided in an interface when the application is developed. The system integrator can benefit from such provided information in the interface of each application to ease the integration process. In this thesis, we have provided the resource and timing requirements of each application in their interfaces for applications that may need several processors to be allocated on when they are developed.

    Although many scheduling techniques have been studied for multiprocessor systems, these techniques are usually based on the assumption that tasks are independent, i.e. do not share resources other than the processors. This assumption is typically not true. In this thesis, we provide an extension to such systems to handle sharing of resources other than processor among tasks. Two traditional approaches exist for multiprocessor systems to schedule tasks on processors. A recent scheduling approach for multiprocessors has combined the two traditional approaches and achieved a hybrid more efficient approach compared to the two previous one. Due to the complex nature of this scheduling approach the conventional approaches for resource sharing could not be used straight forwardly. In this thesis, we have modified resource sharing approaches such that they can be used in such hybrid scheduling systems. A second concern is that enabling resource sharing in the systems can cause unpredictable delays and variations in response time of tasks which can degrade system performance. Therefore, it is of great significance to improve the resource handling techniques to reduce the effect of imposed delays caused by resource sharing in a multiprocessor platform. In this thesis we have proposed alternative techniques for resource handling that can improve system performance for special setups.

  • 5.
    Afshar, Sara
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    J. Bril, Reinder
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems2014Report (Other academic)
    Abstract [en]

    Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.

  • 6.
    Afshar, Sara
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    J. Bril, Reinder
    Technische Universiteit Eindhoven, Eindhoven, The Netherlands.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems2017In: Leibniz Transactions on Embedded Systems, ISSN 2199-2002, no 2Article in journal (Other academic)
    Abstract [en]

    Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.

  • 7.
    Ahmadi, Dara
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Panin, Vadim
    Mälardalen University, School of Innovation, Design and Engineering.
    Skissamarbete på digitala plattformar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Computer-Supported Cooperative Work (CSCW) relates to working in group by distance using computer-based systems and aims to achieve the optimal efficiency in the group's working process. Such systems include computersupported collaborative sketching system. In interaction design, there is an interest in sketch collaboration on digital systems. We have therefore chosen, within the frame of this work, to investigate whether collaborative sketching using digital platform applications lead to an effective way of working for designers and what functionalities such applications should include. To get answers to our questions, we have chosen to create an Android as well as a Web application for sketch collaboration. In our applications we have considered the designers' wishes regarding functionalities. The applications were used in a research to be able to analyze how designers collaborate on digital platforms. Our results have proven that collaborative sketching on digital platforms is a smooth and mobile way of working which involves active discussions, creating new ideas and better solutions, contributes to knowledge transfer and a better working environment and interaction between designers.

  • 8.
    Ahmed, Mobyen Uddin
    Mälardalen University, School of Innovation, Design and Engineering.
    A case-based multi-modal clinical system for stress management2010Licentiate thesis, monograph (Other academic)
    Abstract [en]

    A difficult issue in stress management is to use biomedical sensor signal in the diagnosis and treatment of stress. Clinicians often make their diagnosis and decision based on manual inspection of physiological signals such as, ECG, heart rate, finger temperature etc. However, the complexity associated with manual analysis and interpretation of the signals makes it difficult even for experienced clinicians. Today the diagnosis and decision is largely dependent on how experienced the clinician is interpreting the measurements.  A computer-aided decision support system for diagnosis and treatment of stress would enable a more objective and consistent diagnosis and decisions.

    A challenge in the field of medicine is the accuracy of the system, it is essential that the clinician is able to judge the accuracy of the suggested solutions. Case-based reasoning systems for medical applications are increasingly multi-purpose and multi-modal, using a variety of different methods and techniques to meet the challenges of the medical domain. This research work covers the development of an intelligent clinical decision support system for diagnosis, classification and treatment in stress management. The system uses a finger temperature sensor and the variation in the finger temperature is one of the key features in the system. Several artificial intelligence techniques have been investigated to enable a more reliable and efficient diagnosis and treatment of stress such as case-based reasoning, textual information retrieval, rule-based reasoning, and fuzzy logic. Functionalities and the performance of the system have been validated by implementing a research prototype based on close collaboration with an expert in stress. The case base of the implemented system has been initiated with 53 reference cases classified by an experienced clinician. A case study also shows that the system provides results close to a human expert. The experimental results suggest that such a system is valuable both for less experienced clinicians and for experts where the system may function as a second option.

  • 9.
    Ajmaya, Davi
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Eklund, Dennis
    Mälardalen University, School of Innovation, Design and Engineering.
    Machine learning based pedestrian event monitoring using IMU and GPS2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Understanding the behavior of pedestrians in road transportation is critical to maintain a safe en- vironment. Accidents on road transportation are one of the most common causes of death today. As autonomous vehicles start to become a standard in our society, safety on road transportation becomes increasingly important. Road transportation is a complex system with a lot of dierent factors. Identifying risky behaviors and preventing accidents from occurring requires better under- standing of the behaviors of the dierent persons involved. In this thesis the activities and behavior of a pedestrian is analyzed. Using sensor data from phones, eight dierent events of a pedestrian are classied using machine learning algorithms. Features extracted from phone sensors that can be used to model dierent pedestrian activities are identied. Current state of the art literature is researched to nd relevant machine learning algorithms for a classication model. Two models are implemented using two dierent machine learning algorithms: Articial Neural Network and Hid- den Markov Model. Two dierent experiments are conducted where phone sensor data is collected and classied using the models, achieving a classication accuracy of up to 93%.

  • 10.
    Akan, Batu
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Planning and Sequencing Through Multimodal Interaction for Robot Programming2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Over the past few decades the use of industrial robots has increased the efficiency as well as the competitiveness of several sectors. Despite this fact, in many cases robot automation investments are considered to be technically challenging. In addition, for most small and medium-sized enterprises (SMEs) this process is associated with high costs. Due to their continuously changing product lines, reprogramming costs are likely to exceed installation costs by a large margin. Furthermore, traditional programming methods of industrial robots are too complex for most technicians or manufacturing engineers, and thus assistance from a robot programming expert is often needed. The hypothesis is that in order to make the use of industrial robots more common within the SME sector, the robots should be reprogrammable by technicians or manufacturing engineers rather than robot programming experts. In this thesis, a novel system for task-level programming is proposed. The user interacts with an industrial robot by giving instructions in a structured natural language and by selecting objects through an augmented reality interface. The proposed system consists of two parts: (i) a multimodal framework that provides a natural language interface for the user to interact in which the framework performs modality fusion and semantic analysis, (ii) a symbolic planner, POPStar, to create a time-efficient plan based on the user's instructions. The ultimate goal of this work in this thesis is to bring robot programming to a stage where it is as easy as working together with a colleague.This thesis mainly addresses two issues. The first issue is a general framework for designing and developing multimodal interfaces. The general framework proposed in this thesis is designed to perform natural language understanding, multimodal integration and semantic analysis with an incremental pipeline. The framework also includes a novel multimodal grammar language, which is used for multimodal presentation and semantic meaning generation. Such a framework helps us to make interaction with a robot easier and more natural. The proposed language architecture makes it possible to manipulate, pick or place objects in a scene through high-level commands. Interaction with simple voice commands and gestures enables the manufacturing engineer to focus on the task itself, rather than the programming issues of the robot. The second issue addressed is due to inherent characteristics of communication with the use of natural language; instructions given by a user are often vague and may require other actions to be taken before the conditions for applying the user's instructions are met. In order to solve this problem a symbolic planner, POPStar, based on a partial order planner (POP) is proposed. The system takes landmarks extracted from user instructions as input, and creates a sequence of actions to operate the robotic cell with minimal makespan. The proposed planner takes advantage of the partial order capabilities of POP to execute actions in parallel and employs a best-first search algorithm to seek the series of actions that lead to a minimal makespan. The proposed planner can also handle robots with multiple grippers, parallel machines as well as scheduling for multiple product types.

  • 11.
    Alam, Usman
    Mälardalen University, School of Innovation, Design and Engineering.
    Music in Motion - Smart Soundscapes2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 12. Aleti, Aldeida
    et al.
    Björnander, Stefan
    Mälardalen University, School of Innovation, Design and Engineering.
    Grunske, Lars
    Meedeniya, Indika
    ArcheOpterix: An Extendable Tool for Architecture Optimization of AADL Models2009In: Proceedings of the 2009 ICSE Workshop on Model-Based Methodologies for Pervasive and Embedded Software, MOMPES 2009, 2009, p. 61-71Conference paper (Refereed)
  • 13.
    Alnestig, Henrik
    Mälardalen University, School of Innovation, Design and Engineering.
    On the Feasibility of Low Cost Computer Vision: Building and Testing SimpleEye2014Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    This thesis explores a novel approach to the computer vision eld in the form of lowcost computer vision intended for industrial use. The system proposed in this thesis, calledSimpleEye, is implemented and tested against an existing system. Dierent approachesto object detection and data extraction from a scene, as well as common applications ofcomputer vision in the industry, are examined. Three algorithms are implemented, aimedat dierent industrial applications. These are two types of object recognition, using CannyEdge detection and connected-component labeling, as well as barcode scanning. The tests,each targeting one of the implemented approaches, show promising results for low costcomputer vision. While the system is expectedly lacking in speed, it has no diculties inachieving good result in applications which are not highly time critical. SimpleEye yieldedaccuracy and precision comparable to commercial systems, with parts costing approximately100 USD. The tests show that the system is able to function in several computer visionapplications used today, including visual servoing, blob detection, blob tracking, and barcodescanning.

  • 14.
    Andersson, Edvin
    Mälardalen University, School of Innovation, Design and Engineering.
    Dataöverföring av skilda datatyper på gemensam länk via multiplexing2017Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    When transferring different data types between two sites, they have historically been transferred on separate infrastructures; analog signals separately, and digital data separately. Within the aviation industry, both these data types are still handled today, as transition from analog voice data to digital voice data takes time. To simplify the infrastructure, it is desirable to send all data on the same medium. Time Division Multiplexing (TDM) makes this possible and has been studied with focus on robustness and performance. The study has focused on how TDM devices should be configured with respect to Ethernet frame size to fully utilize link capacity. Theoretical reasoning has been validated by experimental data performed on TDM devices coupled with a fiber link. The number of lost frames for the system has been measured while varying data rates. This was repeated for several Ethernet frame sizes. Smaller frame sizes showed a higher possible transfer rate before data loss was recorded. This shows coherence between theory and experiments. Larger frame sizes were less good at filling the TDM time slots, causing data buffer on the device to overflow faster than for smaller frame sizes. This created data loss in the system. Other factors, such as overhead and payload, implies that the frame size should be chosen by application. Smaller data volumes that are sent frequently have an advantage when using smaller frame sizes, while when handling largeramounts of data that need to be transmitted quickly, it is more efficient to use larger frame sizes

  • 15.
    Andersson, Filip
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Pantzar, Anders
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of a mobile solution for delivering price quotes in the construction industry2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The rapid growth of the mobile consumer market has influenced companies to make their workplace digital and mobile, with the goal to remove ties to a physical workplace, increase productivity, and trivialize tedious tasks. The construction industry is in need of modernization; it is a competitive market and to get a contract it is vital to provide a reasonable price quote fast.This bachelor thesis was performed together with Byggwalle AB in Västerås with the objective to create a mobile solution for price quotes, based on an earlier experimental prototype.

    This thesis will look at how the manual price quote creation process can be sped up and made more transparent to build up trust between the companies and the customers. It will also look at the choices made when developing a mobile application for the construction industry, how to make it flexible enough to fit different kinds of businesses, and look at how the data is administrated using a web based administration system.

    The result of this thesis is a promotional prototype, which sped up the delivery of price quotes from 3 weeks to 3 hours, and will be distributed to selected companies for further testing in the near future. We hope that this product can change the way business is done in construction industry.

  • 16.
    Andersson, Rodny
    Mälardalen University, School of Innovation, Design and Engineering.
    Gränssnittsanayls av en mobilapplikation mot alkoholmissbruk2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I dagens samhälle finns det flera typer av missbruk, ett av det vanligaste är alkoholmissbruk. Alkoholmissbruk har stora negativa effekter för individen men även för samhället. Det är därför viktigt att hitta effektiva metoder för att behandla alkoholmissbruk. Två metoder som används för att skapa en beteendeförändring hos missbrukarna är medicin och konsultation. På senare tid har ett nytt verktyg inom området börjat användas, nämligen mobilapplikationer. De mobilapplikationer vars mål är att skapa en beteendeförändring kan använda sig av designprinciper från ramverket Persuasive systemdesign (PSD). I den här studien har gränssnittet för applikationen Previct Task varit i fokus. Applikationen används som ett verktyg i kombination med att patienten har kontakt med en vårdgivare. Syftet med studien var att få fram ett designförslag som kan öka motivationen hos användarna jämfört med det nuvarande gränssnittet. Resultatet kan användas som riktlinjer för hur gränssnitt för applikationer som ska behandla alkoholmissbruk kan designas. För att få ett resultat har det nuvarande gränssnittet utvärderats genom en heuristisk utvärdering. De viktigaste designprinciperna från PSD och funktionerna i gränssnittet har även identifierats av användarna och vårdgivarna. Resultatet visar att designprinciperna Self-monitoring, Praise, Rewards och Trustworthiness var viktigast för att användarna skulle bli motiverade. Det nuvarande gränssnittet uppfyllde delvis designprinciperna, men jag kunde se att designprinciperna kunde förbättras. Slutsatsen av undersökningen var att applikationens idé var bra men att applikationens struktur och utförande behöver förbättras för att användarna ska känna sig mer motiverade.

  • 17.
    Andersson, Sebastian
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Carlstedt, Gustav
    Mälardalen University, School of Innovation, Design and Engineering.
    Automated Testing of Robotic Systems in Simulated Environments2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the simulations tools available today, simulation can be utilised as a platform for more advanced software testing. By introducing simulations to software testing of robot controllers, the motion performance testing phase can begin at an earlier stage of development. This would benefit all parties involved with the robot controller. Testers at ABB would be able to include more motion performance tests to the regression tests. Also, ABB could save money by adapting to simulated robot tests and customers would be provided with more reliable software updates. In this thesis, a method is developed utilising simulations to create a test set for detecting motion anomalies in new robot controller versions. With auto-generated test cases and a similarity analysis that calculates the Hausdorff distance for a test case executed on controller versions with an induced artificial bug. A test set has been created with the ability to detect anomalies in a robot controller with a bug.

  • 18.
    Andersson, Victoria
    Mälardalen University, School of Innovation, Design and Engineering.
    Touch gestures for process graphics2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The goal of this thesis was to explore and find ways to implement touch gestures in the context of process automation, with the limitation to one specific use case found suitable for touch interaction for ABB’s distributed control system called System 800xA. The typical way to handle the data in System 800xA today is to show and control it through the so called process graphics. It is possible to do this on a touch device today, but the current graphical user interface focus on mouse and keyboard interaction. Because of this some of the common design elements and interaction cues that are in use right now are less suitable when running the system on a touch device. Important characteristics for the process graphics to have for an efficient and delightful user experience when interacting with the system on a touch device were therefore also investigated. To understand if, and if so when and how, an industrial process control system could benefit from touch interaction a PACT analysis was done as a first step. This PACT analysis was then used as a basis for how 15 use cases and their suitability for touch were evaluated. A combination of two out of these 15 use cases were found to be a suitable aim for a prototype that was created. These two use cases involved navigation and controlling of the system and were found suitable for several reasons, including the fact that they are common use cases for when touch interaction with the system is used today. Therefor these two use cases in combination was chosen as the target use case. To find which gestures that were suitable for this use case, an exploratory test was performed where the participants were allowed to show what gestures they perceived as suitable for different tasks that the use case could involve. The findings from these user tests were that the gestures should be kept simple, often only require one hand and one finger usage. Based on these findings, a high-fidelity prototype was implemented on a tablet called Surface Pro. As a way to evaluate the implementation of the high-fidelity prototype an assessment test was conducted. The results from the assessment test indicates that while it is important to adjust the system for touch interaction, by for example use elements in suitable sizes and provide functions adapted for touch interaction, it is also important to replicate the current system where it is possible.

  • 19.
    Andrade, Hugo
    Mälardalen University, School of Innovation, Design and Engineering.
    Software Product Line Architectures: Reviewing the Literature and Identifying Bad Smells2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Software Product Line (SPL) paradigm has proven to be an effective way to achieve large scale reuse in different domains. It takes advantage of common aspects between different products, while also considering product specific features. The architecture plays an important role in SPL engineering, by providing means to better understand and maintain the product-derivation environment. However, it is difficult to evolve such architecture because it is not always clear where and how to refactor. The contribution of this thesis is twofold. First, the current state of the art of software Product Line Architectures (PLAs) is investigated through a systematic mapping study. It provides an overview of the field through the analysis, and categorization of evidence. The study identifies gaps, trends and provides future directions for research. Furthermore, this thesis addresses the phenomenon of architectural bad smells in the context of SPLs. A case study provides an investigation on the implications of such structural properties in a variability-based environment. Prior to the search for smells, the architecture of a sample SPL in the text editor domain is recovered from the source code.

  • 20.
    Andreas, Granholm
    Mälardalen University, School of Innovation, Design and Engineering.
    A migration method for legacy mobile applications2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Developing cross-platform mobile applications as well as migrating existing native applications to other platforms are complex tasks where developers have to face numerous issues. In this thesis we analyze challenges and existing approaches related to cross-platform development and focus specifically on the migration of existing native mobile applications to other platforms. The purpose is to explore existing approaches to cross-platform mobile application development and define whether and how these approaches can be used for migration of legacy applications. As result, a generic method for migrating legacy applications to other platforms has been developed. In order to provide a proof-of-concept, the migration method has been applied to a case-study in industrial settings where the legacy applications were developed for windows 8.1 tablets. The chosen cross-platform development tool for migration in the case-study was Xamarin and a prototype for the platforms Android and iOS were implemented.

  • 21.
    Arvidsson, Karl
    Mälardalen University, School of Innovation, Design and Engineering.
    Wide area motion capture using an array of consumer grade structured light sensors2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis we propose a solution to how a system can find and track people, as well as recognizing their gestures, in a $360^\circ$ field of view using consumer grade products. We describe a system connecting multiple depth cameras in an array and have them operate as a single camera controlled by a single computer. Using a single camera providing features such as detection, tracking and recognizing gestures of people, we specifically focus on the difficulties of preserving these features in moving forward to an array of cameras. We propose a solution based on Microsoft Kinect and Kinect SDK, using linear transformation to account for a fixed camera model to combine skeleton data from an array of Kinect sensors. Furthermore, we use positional based identification to determine whether people are being tracked by another camera in the system. The contributions of this work include insight into the challenges of building this kind of system based on Kinect hardware and software intended for use on a single computer, such as performance bottlenecks, along with possible alternative solutions. In particular, we present performance measurements for a single computer running up to four sensors and show a system that can run satisfactorily with up to at least 5 sensors on today's computers. We show what requirements on hardware can be expected for such a system, as well as where there are potential limits as the number of sensors increase. 

  • 22.
    Axelsson, Jakob
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Papatheocharous, E.
    Swedish Institute of Computer Science (SICS), Sweden.
    Andersson, J.
    Linneaus University, Sweden.
    Characteristics of software ecosystems for Federated Embedded Systems: A case study2014In: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 56, no 11, p. 1457-1475Article in journal (Refereed)
    Abstract [en]

    Context Traditionally, Embedded Systems (ES) are tightly linked to physical products, and closed both for communication to the surrounding world and to additions or modifications by third parties. New technical solutions are however emerging that allow addition of plug-in software, as well as external communication for both software installation and data exchange. These mechanisms in combination will allow for the construction of Federated Embedded Systems (FES). Expected benefits include the possibility of third-party actors developing add-on functionality; a shorter time to market for new functions; and the ability to upgrade existing products in the field. This will however require not only new technical solutions, but also a transformation of the software ecosystems for ES. Objective This paper aims at providing an initial characterization of the mechanisms that need to be present to make a FES ecosystem successful. This includes identification of the actors, the possible business models, the effects on product development processes, methods and tools, as well as on the product architecture. Method The research was carried out as an explorative case study based on interviews with 15 senior staff members at 9 companies related to ES that represent different roles in a future ecosystem for FES. The interview data was analyzed and the findings were mapped according to the Business Model Canvas (BMC). Results The findings from the study describe the main characteristics of a FES ecosystem, and identify the challenges for future research and practice. Conclusions The case study indicates that new actors exist in the FES ecosystem compared to a traditional supply chain, and that their roles and relations are redefined. The business models include new revenue streams and services, but also create the need for trade-offs between, e.g., openness and dependability in the architecture, as well as new ways of working. © 2014 The Authors. Published by Elsevier B.V.

  • 23.
    Aysan, Hüseyin
    Mälardalen University, School of Innovation, Design and Engineering.
    New Strategies for Ensuring Time and Value Correctness in Dependable Real-Time Systems2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Dependable real-time embedded systems are typically composed of a number of heterogeneous computing nodes, heterogeneous networks that connect them and tasks with multiple criticality levels allocated to the nodes. The heterogeneous nature of the hardware, results in a varying vulnerability to different types of hardware failures. For example, a computing node with effective shielding shows higher resistance to transient failures caused by environmental conditions such as radiation or temperature changes than an unshielded node. Similarly, resistance to permanent failures can vary depending on the manufacturing procedures used. Vulnerability to different types of errors of a task which may lead to a system failure, depends on several factors, such as the hardware on which the task runs and communicates, the software architecture and the implementation quality of the software, and varies from task to task. This variance, as well as the different criticality levels and real-time requirements of tasks, necessitate novel fault-tolerance approaches to be developed and used, in order to meet the stringent dependability requirements of resource-constrained real-time systems.

     

    In this thesis, the major contribution is four-fold. Firstly, we describe an error classification for real-time embedded systems and address error propagation aspects. The goal of this work is to perform the analysis on a given system, in order to find bottlenecks in satisfying dependability requirements and to provide guidelines on the usage of appropriate error detection and fault tolerance mechanisms.

     

    Secondly, we present a time-redundancy approach to provide a priori guarantees in fixed-priority scheduling (FPS) such that the system will be able to tolerate one value error per every critical task instance by re-execution of every critical task instance or execution of alternate tasks before deadlines, while keeping the associated costs minimized.

     

    Our third contribution is a new approach, Voting on Time and Value (VTV) which extends the N-modular redundancy approach by explicitly considering both value and timing errors, such that correct value is produced at a correct time, under specified assumptions. We illustrate our voting approach by instantiating it in the context of the well-known triple modular redundancy (TMR) approach. Further, we present a generalized voting algorithm targeting NMR that enables a high degree of customization from the user perspective.

     

    Finally, we propose a novel cascading redundancy approach within a generic fault tolerant scheduling framework. The proposed approach is capable of tolerating errors with a wider coverage (with respect to error frequency and error types) than our proposed time and space redundancy approaches in isolation, allows tasks with mixed criticality levels, is independent of the scheduling technique and, above all, ensures that every critical task instance can be feasibly replicated in both time and/or space. The fault-tolerance techniques presented in this thesis address various different error scenarios that can be observed in real-time embedded systems with respect to the types of errors and frequency of occurrence, and can be used to achieve the ultra-high levels of dependability which is required in many critical systems.

  • 24.
    Barua, Shaibal
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Intelligent Driver Mental State Monitoring System Using Physiological Sensor Signals2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Driving a vehicle involves a series of events, which are related to and evolve with the mental state (such as sleepiness, mental load, and stress) of the driv- er. These states are also identified as causal factors of critical situations that can lead to road accidents and vehicle crashes. These driver impairments need to be detected and predicted in order to reduce critical situations and road accidents. In the past years, physiological signals have become conven- tional measures in driver impairment research. Physiological signals have been applied in various studies to identify different levels of mental load, sleepiness, and stress during driving.

    This licentiate thesis work has investigated several artificial intelligence algorithms for developing an intelligent system to monitor driver mental state using physiological signals. The research aims to measure sleepiness and mental load using Electroencephalography (EEG). EEG signals, if pro- cessed correctly and efficiently, have potential to facilitate advanced moni- toring of sleepiness, mental load, fatigue, stress etc. However, EEG signals can be contaminated with unwanted signals, i.e., artifacts. These artifacts can lead to serious misinterpretation. Therefore, this work investigates EEG arti- fact handling methods and propose an automated approach for EEG artifact handling. Furthermore, this research has also investigated how several other physiological parameters (Heart Rate (HR) and Heart Rate Variability (HRV) from the Electrocardiogram (ECG), Respiration Rate, Finger Tem- perature (FT), and Skin Conductance (SC)) to quantify drivers’ stress. Dif- ferent signal processing methods have been investigated to extract features from these physiological signals. These features have been extracted in the time domain, in the frequency domain as well as in the joint time-frequency domain using wavelet analysis. Furthermore, data level signal fusion has been proposed using Multivariate Multiscale Entropy (MMSE) analysis by combining five physiological sensor signals. Primarily Case-Based Reason- ing (CBR) has been applied for drivers’ mental state classification, but other Artificial intelligence (AI) techniques such as Fuzzy Logic, Support Vector Machine (SVM) and Artificial Neural Network (ANN) have been investigat- ed as well.

    For drivers’ stress classification, using the CBR and MMSE approach, the system has achieved 83.33% classification accuracy compared to a human expert. Moreover, three classification algorithms i.e., CBR, an ANN, and a SVM were compared to classify drivers’ stress. The results show that CBR has achieved 80% and 86% accuracy to classify stress using finger tempera- ture and heart rate variability respectively, while ANN and SVM reached an accuracy of less than 80%. 

  • 25.
    Barua, Shaibal
    Mälardalen University, School of Innovation, Design and Engineering.
    Multi-sensor Information Fusion for Classification of Driver's Physiological Sensor Data2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Physiological sensor signals analysis is common practice in medical domain for diagnosis andclassification of various physiological conditions. Clinicians’ frequently use physiologicalsensor signals to diagnose individual’s psychophysiological parameters i.e., stress tiredness,and fatigue etc. However, parameters obtained from physiological sensors could vary becauseof individual’s age, gender, physical conditions etc. and analyzing data from a single sensorcould mislead the diagnosis result. Today, one proposition is that sensor signal fusion canprovide more reliable and efficient outcome than using data from single sensor and it is alsobecoming significant in numerous diagnosis fields including medical diagnosis andclassification. Case-Based Reasoning (CBR) is another well established and recognizedmethod in health sciences. Here, an entropy based algorithm, “Multivariate MultiscaleEntropy analysis” has been selected to fuse multiple sensor signals. Other physiologicalsensor signals measurements are also taken into consideration for system evaluation. A CBRsystem is proposed to classify ‘healthy’ and ‘stressed’ persons using both fused features andother physiological i.e. Heart Rate Variability (HRV), Respiratory Sinus Arrhythmia (RSA),Finger Temperature (FT) features.

    The evaluation and performance analysis of the system have been done and the results ofthe classification based on data fusion and physiological measurements are presented in thisthesis work.

  • 26.
    Barua, Shaibal
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Multivariate Data Analytics to Identify Driver’s Sleepiness, Cognitive load, and Stress2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Driving a vehicle in a dynamic traffic environment requires continuous adaptation of a complex manifold of physiological and cognitive activities. Impaired driving due to, for example, sleepiness, inattention, cognitive load or stress, affects one’s ability to adapt, predict and react to upcoming traffic events. In fact, human error has been found to be a contributing factor in more than 90% of traffic crashes. Unfortunately, there is no robust, objective ground truth for determining a driver’s state, and researchers often revert to using subjective self-rating scales when assessing level of sleepiness, cognitive load or stress. Thus, the development of better tools to understand, measure and monitor human behaviour across diverse scenarios and states is crucial. The main objective of this thesis is to develop objective measures of sleepiness, cognitive load and stress, which can later be used as research tools, either to benchmark unobtrusive sensor solutions or when investigating the influence of other factors on sleepiness, cognitive load, and stress.

    This thesis employs multivariate data analysis using machine learning to detect and classify different driver states based on physiological data. The reason for using rather intrusive sensor data, such as electroencephalography (EEG), electrooculography (EOG), electrocardiography (ECG), skin conductance, finger temperature, and respiration is that these methods can be used to analyse how the brain and body respond to internal and external changes, including those that do not generate overt behaviour. Moreover, the use of physiological data is expected to grow in importance when investigating human behaviour in partially automated vehicles, where active driving is replaced by passive supervision.

    Physiological data, especially the EEG is sensitive to motion artifacts and noise, and when recorded in naturalistic environments such as driving, artifacts are unavoidable. An automatic EEG artifact handling method ARTE (Automated aRTifacts handling in EEG) was therefore developed. When used as a pre-processing step in the classification of driver sleepiness, ARTE increased classification performance by 5%. ARTE is data-driven and does not rely on additional reference signals or manually defined thresholds, making it well suited for use in dynamic settings where unforeseen and rare artifacts are commonly encountered. In addition, several machine-learning algorithms have been developed for sleepiness, cognitive load, and stress classification. Regarding sleepiness classification, the best achieved accuracy was achieved using a Support Vector Machine (SVM) classifier. For multiclass, the obtained accuracy was 79% and for binary class it was 93%. A subject-dependent classification exhibited a 10% improvement in performance compared to the subject-independent classification, suggesting that much can be gained by using personalized classifiers. Moreover, by embedding contextual information, classification performance improves by approximately 5%. In regard to cognitive load classification, a 72% accuracy rate was achieved using a random forest classifier. Combining features from several data sources may improve performance, and indeed, we observed classification performance improvement by 10%-20% compared to using features from a single data source. To classify drivers’ stress, using the Case-based reasoning (CBR) and data fusion approach, the system achieved an 83.33% classification accuracy rate.

    This thesis work encourages the use of multivariate data for detecting and classifying driver states, including sleepiness, cognitive load, and stress. A univariate data source often presents challenges, since features from a single source or one just aspect of the feature are not entirely reliable; Therefore, multivariate information requires accurate driver state detection. Often, driver states are a subjective experience, in which other contextual data plays a vital role. Thus, the implication of incorporating contextual information in the classification scheme is presented in this thesis work. Although there are several commonalities, physiological signals are modulated differently in different driver states; Hence, multivariate data could help detect multiple driver states simultaneously – for example, cognitive load detection when a person is under the influence of different levels of stress.

  • 27.
    Begum, Shahina
    Mälardalen University, School of Innovation, Design and Engineering.
    A Personalised Case-Based Stress Diagnosis System Using Physiological Sensor Signals2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stress is an increasing problem in our present world. It is recognised that increased exposure to stress may cause serious health problems if undiagnosed and untreated. In stress medicine, clinicians’ measure blood pressure, Electrocardiogram (ECG), finger temperature and respiration rate etc. during a number of exercises to diagnose stress-related disorders. However, in practice, it is difficult and tedious for a clinician to understand, interpret and analyze complex, lengthy sequential sensor signals. There are few experts who are able to diagnose and predict stress-related problems. Therefore, a system that can help clinicians in diagnosing stress is important.

    This research work has investigated Artificial Intelligence techniques for developing an intelligent, integrated sensor system to establish diagnosis and treatment plans in the psychophysiological domain. This research uses physiological parameters i.e., finger temperature (FT) and heart rate variability (HRV) for quantifying stress levels.  Large individual variations in physiological parameters are one reason why case-based reasoning is applied as a core technique to facilitate experience reuse by retrieving previous similar cases. Feature extraction methods to represent important features of original signals for case indexing are investigated. Furthermore, fuzzy techniques are also employed and incorporated into the case-based reasoning system to handle vagueness and uncertainty inherently existing in clinicians’ reasoning.

    The evaluation of the approach is based on close collaboration with experts and measurements of FT and HRV from ECG data. The approach has been evaluated with clinicians and trial measurements on subjects (24+46 persons). An expert has ranked and estimated the similarity for all the subjects during classification. The result shows that the system reaches a level of performance close to an expert in both the cases. The proposed system could be used as an expert for a less experienced clinician or as a second opinion for an experienced clinician to supplement their decision making tasks in stress diagnosis.

  • 28.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Multi-core Composability in the Face of Memory Bus Contention2012Conference paper (Refereed)
    Abstract [en]

    In this paper we describe the problem of achieving composability of independently developed real-time subsystems to be executed on a multicore platform.We evaluate existing work for achieving real-time performance on multicores and illustrate their lack with respect to composability. To better address composability we present a multi-resource server-based scheduling technique to provide predictable performance when composing multiple subsystems on a multicore platform. To achieve composability also on multicore platforms, we propose to add memory-bandwidth as an additional server resource. Tasks within our multi-resource servers are guaranteed both CPU- and memory-bandwidth; thus the performance of a server will become independent of resource usage by tasks in other servers. We are currently implementing multi-resource servers for the Enea’s OSE operating system for a P4080 8-core processor to be tested with software for a 3G-basestation.

  • 29.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Department of Computer Science, KAIST University , Korea.
    Overrun Methods and Resource Holding Times for Hierarchical Scheduling of Semi-Independent Real-Time Systems2010In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, Vol. 6, no 1, p. 93-104Article in journal (Refereed)
    Abstract [en]

    The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework toenable compositional schedulability analysis of embedded software systems with real-time properties. Inthis paper a software system consists of a number of semi-independent components called subsystems.Subsystems are developed independently and later integrated to form a system. To support this designprocess, in the paper, the proposed methods allow non-intrusive configuration and tuning of subsystemtiming-behaviour via subsystem interfaces for selecting scheduling parameters.This paper considers three methods to handle overruns due to resource sharing between subsystemsin the HSF. For each one of these three overrun methods corresponding scheduling algorithms and associatedschedulability analysis are presented together with analysis that shows under what circumstances one or the other is preferred. The analysis is generalized to allow for both Fixed Priority Scheduling (FPS)and Earliest Deadline First (EDF) scheduling. Also, a further contribution of the paper is the techniqueof calculating resource-holding times within the framework under different scheduling algorithms; theresource holding times being an important parameter in the global schedulability analysis.

  • 30.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    SIRAP: A Synchronization Protocol for Hierarchical Resource Sharing in Real-Time Open Systems2007In: EMSOFT'07: Proceedings of the Seventh ACM and IEEE International Conference on Embedded Software, 2007, p. 279-288Conference paper (Refereed)
    Abstract [en]

    This paper presents a protocol for resource sharing in a hierarchical real-time scheduling framework. Targeting real-time open systems, the protocol and the scheduling framework significantly reduce the efforts and errors associated with integrating multiple semi-independent subsystems on a single processor. Thus, our proposed techniques facilitate modern software development processes, where subsystems are developed by independent teams (or subcontractors) and at a later stage integrated into a single product. Using our solution, a subsystem need not know, and is not dependent on, the timing behaviour of other subsystems; even though they share mutually exclusive resources. In this paper we also prove the correctness of our approach and evaluate its efficiency.

  • 31.
    Bergström, Albert
    Mälardalen University, School of Innovation, Design and Engineering.
    A Survey on Developers’ Preferences in Integrated Development Environments2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Software development is a demanding task where developers face great challenges. Development tools are expected to be user-friendly. However, little research has been done to understand developers’ needs and priorities when it comes to such tools, so called Integrated Development Environments (IDEs). It is important to gain a better insight into developers’ prioritization of IDE qualities, in order to be able to make such tools more efficient and better tailored to their users’ real needs. The objective of this thesis is to gain a deeper understanding of software developers’ perspective regarding IDEs with the goal of facilitating further improvements of these tools. This thesis report presents the results of a quantitative survey, responded by twenty professional software developers, which focuses on developers’ prioritization of qualities in adopted IDEs and their perceived satisfaction with the qualities themselves and the IDEs overall. Moreover, we investigate whether limiting developers’ choice of IDE also affects their overall satisfaction of chosen IDEs. By analyzing the results, we conclude that developers perceive reliability, ease of use and efficiency as, on one hand the most important qualities of IDEs, and on the other hand those most in need of improvements. The results also suggest that developers’ satisfaction with their IDEs is not significantly affected by limiting their choice of development tools.

  • 32.
    Berndtsson, Andreas
    Mälardalen University, School of Innovation, Design and Engineering.
    VPN Mesh in Industrial Networking2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis report describes the process and present the results gained while evaluating available VPN mesh solutions and equipment for integration into Industrial systems. The task was divided into several sub steps; summarize the previous work done in the VPN mesh area, evaluate the available VPN mesh solutions, verify that the interesting equipment comply with the criteria set by ABB and lastly verify that the equipment can be integrated transparently into already running systems. The result shows that there is equipment that complies with the criteria, which can also be integrated transparently into running systems. The result also shows that IPSec should be used as the VPN protocol since IPSec can make use of the crypto hardware whereas TLS based VPNs currently cannot. Even though the implementation of secure gateways would provide authentication and authorization to the network, the cost of implementing these gateways would be great. The best solution would be to present the evaluated equipment as an optional feature instead of making it standard equipment in each system.

  • 33.
    Bexelius, Tobias
    Mälardalen University, School of Innovation, Design and Engineering.
    HaGPipe: Programming the graphics pipeline in Haskell2009Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    In this paper I present the domain specific language HaGPipe for graphics programming in Haskell. HaGPipe has a clean, purely functional and strongly typed interface and targets the whole graphics pipeline including the programmable shaders of the GPU. It can be extended for use with various backends and this paper provides two different ones. The first one generates vertex and fragment shaders in Cg for the GPU, and the second one generates vertex shader code for the SPUs on PlayStation 3. I will demonstrate HaGPipe's many capabilities of producing optimized code, including an extensible rewrite rule framework, automatic packing of vertex data, common sub expression elimination and both automatic basic block level vectorization and loop vectorization through the use of structures of arrays.

  • 34.
    Bihi, Ahmed
    Mälardalen University, School of Innovation, Design and Engineering.
    Analysis of similarity and differences between articles using semantics2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Adding semantic analysis in the process of comparing news articles enables a deeper level of analysis than traditional keyword matching. In this bachelor’s thesis, we have compared, implemented, and evaluated three commonly used approaches for document-level similarity. The three similarity measurement selected were, keyword matching, TF-IDF vector distance, and Latent Semantic Indexing. Each method was evaluated on a coherent set of news articles where the majority of the articles were written about Donald Trump and the American election the 9th of November 2016, there were several control articles, about random topics, in the set of articles. TF-IDF vector distance combined with Cosine similarity and Latent Semantic Indexing gave the best results on the set of articles by separating the control articles from the Trump articles. Keyword matching and TF-IDF distance using Euclidean distance did not separate the Trump articles from the control articles. We implemented and performed sentiment analysis on the set of news articles in the classes positive, negative and neutral and then validated them against human readers classifying the articles. With the sentiment analysis (positive, negative, and neutral) implementation, we got a high correlation with human readers (100%).

  • 35.
    Billman, Albin
    Mälardalen University, School of Innovation, Design and Engineering.
    Solving flow shop problems using a forward-chaining partial-order planner2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Planning is the task of putting together a sequence of actions that takes a start state to a goal state. Since planning is a crucial part of human intelligence it is also a crucial part of artificial intelligence. As with human planning there are many different ways of AI planning and many different problems to plan. This thesis aims to discover how well a specific way of AI planning performs on a specific sort of problem. The planner that was investigated is called the POPF planner which is a forward-chaining partial-order planner which is an attempt at merging two different ways of planning. This was done to see how well this relatively uncommon method of planning compares to other more traditional methods of planning such as forward-chaining planners when solving a flow shop problem. A flow shop problem is a problem regarding minimizing the idle time for a facility that contains a number of m machines that need to do n jobs. Each of the n jobs 1…n have to be processed on m machines 1…m in that order. Tests were done to see how the POPF planner performed in comparison to planners that work differently. This was done by creating a flow shop problem suitable for testing and then testing the POPF planner on the problem and comparing the results to two other planners. The other planners being the COLIN and TFD planners which both work differently from each other and the POPF planner. Suggestions were also made for how the POPF planner could potentially be improved using additional methods such as landmarks. The results of the test show that the POPF planner is better than the COLIN planner and as good if not better than the TFD planner depending on the complexity of the problem. An additional test was done using the POPStar planner that specializes in the sorts of problem that was created for testing. This POPStar planner outperformed the other planners as expected but it loses in flexibility since it cannot solve problems defined in PDDL. The final results show that the POPF planner performs on a similar level to other general planners when it comes to solving flow shop problems while still having some of the benefits of being a partial-order planner such as being more flexible than a totally-ordered planner.

  • 36.
    Björkholdt, Jan
    Mälardalen University, School of Innovation, Design and Engineering.
    jFunda2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Kadesjös Ingenjörsbyrå AB, ett konsultföretag inom bygg- och VVS-sektorn med ca 50 anställda, använder ett egenskrivet BASIC program i DOS för beräkning av grundfundament i betong med grundsula och plintskaft avseende stabilitet och erforderlig armering. I dagsläget finns det ungefär 10 användare av programmet.

    Några kända problem med programmet är att varje dator måste konfigureras manuellt med kommandopromptens NET USE kommando. Detta för att en anslutning av nätverksskrivaren till den lokala porten LPT1 måste finnas för att utskriften ska fungera. Dessutom kan varken indata eller resultat från ett fundament sparas.

    Detta examensarbete behandlar arbetet för att konvertera det äldre DOS programmet till ett modernare fönsterbaserat programspråk med möjlighet att kunna spara fundamenten för respektive projekt.

  • 37.
    Björnander, Stefan
    Mälardalen University, School of Innovation, Design and Engineering.
    Methods and Tool Support for Analyzing Architectural Models of Embedded Systems2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Embedded systems are ubiquitous in the modern world. They are microcomputers most often included incomplete devices consisting of software and hardware. Embedded systems range from small devices to large systems monitoring and controlling complex processes. Design and development of such systems is a complex task, since embedded systems often need to fulfill extra-functional requirements, on top of functional ones, within constrained amounts of platform resources. Some embedded systems are mission critical; hence, they are not allowed to fail during the mission. One way to ensure that a system works in accordance to its specification is to define the system in an Architecture Description Language (ADL) and apply formal verification methods. The Architecture Design and Analysis Language (AADL) has become popular in the avionic and automobile industry, and is equipped with several annexes, among them the Behavior Annex. However, AADL still misses a formal semantics, which prevents the possibility to prove correctness of architecture features by performing model checking on AADL models. Moreover, AADL does not support time annotations, which prevents modeling of real-time systems in AADL.

    In this thesis, we address these issues by presenting a formal analysis framework including a denotationalsemantics for a subset of the AADL and its Behavior Annex, which evaluates properties defined in Computation Tree Logic (CTL) by providing model checking. Model checking is a formal verification method that has proved to be powerful as well as effective. Our AADL-semantics is supported by a tool with an implementation of the semantics in Standard ML, which in turn is encapsulated in an Eclipse plugin.We also present a time annotation extension of AADL, implemented in a tool translating time annotated AADL and its Behavior Annex into the Timed Abstract State Machine (TASM) for simulation of real-time features. Another closely related problem is how to achieve optimal component distribution; in order to address this issue we have developed a tool that perform near-optional component distribution in regard to a series of parameters.

    The research results, which have been validated thought case studies, provides the possibility for a system engineer to model a system and prove its correctness. The research has been conducted in the context of the PROGRESS research center, for predictable embedded software systems.

  • 38.
    Björnander, Stefan
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Grunske, Lars
    Faculty of ICT, Swinburne University of Technology, Hawthorn VIC 3122, Australia.
    Lundqvist, Kristina
    Mälardalen University, School of Innovation, Design and Engineering.
    Timed Simulation of Extended AADL-Based Architecture Specifications with Timed Abstract State Machines2009In: Architectures for Adaptive Software Systems: 5th International Conference on the Quality of Software Architectures, QoSA 2009, East Stroudsburg, PA, USA, June 24-26, 2009 Proceedings, Berlin: Springer, 2009, p. 101-115Chapter in book (Refereed)
    Abstract [en]

    The Architecture Analysis and Design Language (AADL) is a popular language for architectural modeling and analysis of software intensive systems in application domains such as automotive, avionics, railway and medical systems. These systems often have stringent real-time requirements. This paper presents an extension to AADL's behavior model using time annotations in order to improve the evaluation of timing properties in AADL. The translational semantics of this extension is based on mappings to the Timed Abstract State Machines (TASM) language. As a result, timing analysis with timed simulation or timed model checking is possible. The translation is supported by art Eclipse-based plug-in and the approach is validated with a case study of an industrial production cell system.

  • 39.
    Björnander, Stefan
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Seceleanu, Cristina
    Mälardalen University, School of Innovation, Design and Engineering.
    Lundqvist, Kristina
    Mälardalen University, School of Innovation, Design and Engineering.
    Pettersson, Paul
    Mälardalen University, School of Innovation, Design and Engineering.
    ABV: A Verifier for the Architecture Analysis and Description Language (AADL)2011In: 16th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS), 2011, 2011, p. 355-360Conference paper (Refereed)
  • 40.
    Blomqvist, Simon
    Mälardalen University, School of Innovation, Design and Engineering.
    Improvement Proposal for Wireless Office Networks2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wireless networks nowadays are more affordable and faster than ever and thus many companies incorporate wireless solutions into their networks. However, a lot of challenges are introduced with wireless implementations and knowing how to make the best use of one’s equipment can lead to increased quality of experience, higher security, and improved manageability. The Stockholm based company NetEnt has recently moved into a new office and enhancements on its new wireless network are to be implemented throughout the year. Wireless networks are complex to implement and even if the installation works properly there are still improvements that could be made. The presumption is that such improvements could lead to increased delivery quality for NetEnt. Thus, the main goal of this thesis work is to create a proposal of improvements based on best practices for NetEnt. During the thesis work, an investigation has been conducted to find general wireless network recommendations and vendor specific best practices. Recommendations were found in areas such as 802.11 frequency bands and standards, forwarding architecture, security, and management. The study showed that few recommendations alone would make a significant difference, but together they could make a noticeable boost to the network. The recommendations were compared to NetEnt’s network and an analysis of the differences was performed. The study showed that some advocated proposals were already met while other were planned to be implemented in a near future. The conducted analysis includes the remainder of best practices and is to be seen as a proposal of improvements, which is expected to help NetEnt’s IT department to increase the overall condition of the network. 

  • 41.
    Bohlin, Markus
    Mälardalen University, School of Innovation, Design and Engineering.
    A Study of Combinatorial Optimization Problems in Industrial Computer Systems2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A combinatorial optimization problem is an optimization problem where the number of possible solutions are finite and grow combinatorially with the problem size. Combinatorial problems exist everywhere in industrial systems. This thesis focuses on solving three such problems which arise within two different areas where industrial computer systems are often used. Within embedded systems and real-time systems, we investigate the problems of allocating stack memory for an system where a shared stacks may be used, and of estimating the highest response time of a task in a system of industrial complexity. We propose a number of different algorithms to compute safe upper bounds on run-time stack usage whenever the system supports stack sharing. The algorithms have in common that they can exploit commonly-available information regarding timing behaviour of the tasks in the system. Given upper bounds on the individual stack usage of the tasks, it is possible to estimate the worst-case stack behaviour by analysing the possible and impossible preemption patterns. Using relations on offset and precedences, we form a preemption graph, which is further analysed to find safe upper-bounds on the maximal preemptions chain in the system. For the special case where all tasks exist in a single static schedule and share a single stack, we propose a polynomial algorithm to solve the problem. For generalizations of this problem, we propose an exact branch-and-bound algorithm for smaller problems and a polynomial heuristic algorithm for cases where the branch-and-bound algorithm fails to find a solution in reasonable time. All algorithms are evaluated in comprehensive experimental studies. The polynomial algorithm is implemented and shipped in the developer tool set for a commercial real-time operating system, Rubus OS. The second problem we study in the thesis is how to estimate the highest response time of a specified task in a complex industrial real-time system. The response-time analysis is done using a best-effort approach, where a detailed model of the system is simulated on input constructed using a local search procedure. In an evaluation on three different systems we can see that the new algorithm were able to produce higher response times much faster than what has previously been possible. Since the analysis is based on simulation and measurement, the results are not safe in the sense that they are always higher or equal to the true response time of the system. The value of the method lies instead in that it makes it possible to analyse complex industrial systems which cannot be analysed accurately using existing safe approaches. The third problem is in the area of maintenance planning, and focus on how to dynamically plan maintenance for industrial systems. Within this area we have focused on industrial gas turbines and rail vehicles.  We have developed algorithms and a planning tool which can be used to plan maintenance for gas turbines and other stationary machinery. In such problems, it is often the case that performing several maintenance actions at the same time is beneficial, since many of these jobs can be done in parallel, which reduces the total downtime of the unit. The core of the problem is therefore how to (or how not to) group maintenance activities so that a composite cost due to spare parts, labor and loss of production due to downtime is minimized. We allow each machine to have individual schedules for each component in the system. For rail vehicles, we have evaluated the effect of replanning maintenance in the case where the component maintenance deadline is set to reflect a maximum risk of breakdown in a Gaussian failure distribution. In such a model, we show by simulation that replanning of maintenance can reduce the number of maintenance stops when the variance and expected value of the distribution are increased.  For the gas turbine maintenance planning problem, we have evaluated the planning software on a real-world scenario from the oil and gas industry and compared it to the solutions obtained from a commercial integer programming solver. It is estimated that the availability increase from using our planning software is between 0.5 to 1.0 %, which is substantial considering that availability is currently already at 97-98 %.

  • 42.
    Boqvist, Anders
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Gyllhag, Oscar
    Mälardalen University, School of Innovation, Design and Engineering.
    IPv6 in WeOS: Initial support for IPv6 in WeOS2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Westermo is a company that develops industrial standardized network equipment for harsh environments. Our task was to help the company prepare for future demands regarding IP communication. Westermo has customers and branches around the world, in order to meet market demands and competitor development IP version 6 support is of great interest.Next generation of IP communication is IPv6 and to prepare for the future and present market demands IPv6 support is needed in Westermo´s products. This thesis assignment is meant to investigate and give a proof of concept solution for basic IPv6 support in Westermo Operating System (WeOS).The areas of interest this thesis involves are IP settings and routing support. IP settings include ability to activate IPv6, assigning address to interface and related tasks. Routing support imply creation of routes and default-gateway, that gives the switches basic IPv6 routing capabilities. Switches should be capable of sending IPv6 router advertisement messages, and perform static IPv6 routing.Performing changes in IPv6 support means that modifications in the Command Line Interface (CLI)-context are necessary, in order to make configuration user-friendly. Therefore a proposed extension of the CLI-syntax is required. Implementations of the proposed CLI-syntax are done into Westermo´s main operating system WeOS.Our work has fulfilled the general expectations and placed a foundation for IPv6 support. Through proof of concept tests and implementations, WeOS is close to reach and meet the primary functionality with IPv6.Westermo is a company that develops industrial standardized network equipment for harsh environments. Our task was to help the company prepare for future demands regarding IP communication. Westermo has customers and branches around the world, in order to meet market demands and competitor development IP version 6 support is of great interest.Next generation of IP communication is IPv6 and to prepare for the future and present market demands IPv6 support is needed in Westermo´s products. This thesis assignment is meant to investigate and give a proof of concept solution for basic IPv6 support in Westermo Operating System (WeOS).The areas of interest this thesis involves are IP settings and routing support. IP settings include ability to activate IPv6, assigning address to interface and related tasks. Routing support imply creation of routes and default-gateway, that gives the switches basic IPv6 routing capabilities. Switches should be capable of sending IPv6 router advertisement messages, and perform static IPv6 routing.Performing changes in IPv6 support means that modifications in the Command Line Interface (CLI)-context are necessary, in order to make configuration user-friendly. Therefore a proposed extension of the CLI-syntax is required. Implementations of the proposed CLI-syntax are done into Westermo´s main operating system WeOS.Our work has fulfilled the general expectations and placed a foundation for IPv6 support. Through proof of concept tests and implementations, WeOS is close to reach and meet the primary functionality with IPv6.

  • 43.
    Brown, Johan
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Gustafsson Brokås, Alexander
    Mälardalen University, School of Innovation, Design and Engineering.
    Hurtig, Niklas
    Mälardalen University, School of Innovation, Design and Engineering.
    Johansson, Tobias
    Mälardalen University, School of Innovation, Design and Engineering.
    Designing and implementing a small scale Internet Service Provider2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this thesis is to design and implement a small scaleInternet Service Provider (ISP) for the NetCenter sub department atMälardalen University. The ISP is intended to give NetCenter a networkseparate from the University’s network, providing them with a moreflexible environment for lab purposes. This will give their students anopportunity to experience a larger backbone with Internet accessibility,which has not been previously available. At the same time it will place theteachers in control of the network in the NetCenter lab premises.The network is designed with a layered approach including an Internetaccess layer, a larger core segment and a distribution layer with aseparated lab network. It also incorporates both a public and a privateserver network, housing servers running e.g. Windows Active Directory,external DNS services, monitoring tools and logging applications. TheInternet access is achieved by peering with SUNET providing a full BGPfeed.This thesis report presents methods, implementations and results involvedin successfully creating the NetCenter ISP as both a lab network and anInternet provider with a few inevitable shortcomings; the most prominentbeing an incomplete Windows Domain setup.

  • 44.
    Bucaioni, Alessio
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Model-driven Development Approach with Temporal Awareness for Vehicular Embedded Systems2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Considering the ubiquitousness of software in modern vehicles, its increased value and development cost, an efficient software development became of paramount importance for the vehicular domain. It has been identified that early verification of non functional properties of  vehicular embedded software such as, timing, reliability and safety, is crucial to efficiency. However, early verification of non functional properties is hard to achieve with traditional software development approaches due to the abstraction and the lack of automation of these methodologies.

     

    This doctoral thesis aims at improving efficiency in vehicular embedded software development by minimising the need for late, expensive and time consuming software modifications with early design changes, identified through timing verification, which usually are cheaper and faster. To this end, we introduce a novel model-driven approach which exploits the interplay of two automotive-specific modelling languages for the representation of functional and execution models and defines a suite of model transformations for their automatic integration.

     

    Starting from a functional model (expressed by means of EAST-ADL), all the execution models (expressed by means of the Rubus Component Model) entailing unique timing configurations are derived. Schedulability analysis selects the set of the feasible execution models with respect to specified timing requirements. Eventually, a reference to the selected execution models along with their analysis results is automatically created in the related functional model to allow the engineer to investigate them.

     

    The main scientific contributions of this doctoral thesis are i) a metamodel definition for the Rubus Component Model, ii) an automatic mechanism for the generation of Rubus models from EAST-ADL, iii) an automatic mechanism for the selection and back-propagation of the analysis results and related Rubus models to design level and iv) a compact notation for visualising the selected Rubus models by means of a single execution model.

  • 45.
    Bucaioni, Alessio
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Arcticus Systems AB .
    Raising Abstraction of Timing Analysis through Model-Driven Engineering2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

     The complexity of software running on vehicular embedded systems is constantly

    increasing and this negatively affects its development costs and time to

    market. One way to deal with these issues is to boost abstraction in the form

    of models to (i) ease the reasoning about the system architecture, (ii) automate

    certain stages of the development, (iii) early detect flaws in the system architecture

    through fundamental analysis and (iv) take appropriate countermeasures

    before the system is implemented.

    Considering the importance of timing requirements in the design of software

    for vehicular embedded systems, in this licentiate thesis we leverage

    Model-Driven Engineering for realizing a semi-automatic approach which allows

    the developer to perform end-to-end delay timing analysis on design models,

    without having to manually model timing elements and set their values.

    The proposed approach, starting from a design model of an automotive

    software functionality, automatically generates a set of models enriched with

    timing elements whose values are set at generation time. End-to-end delay timing

    analysis is run on the generated models and, based on the analysis results,

    the approach automatically selects the generated models which better meet a

    specific set of timing requirements.

  • 46.
    Bucaioni, Alessio
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Arcticus Systems AB.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ciccozzi, Federico
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Metamodel for the Rubus Component Model: Extensions for Timing and Model Transformation from EAST-ADL2017In: IEEE Access, E-ISSN 2169-3536, ISSN 2169-3536, p. 9005-9020Article in journal (Refereed)
    Abstract [en]

    According to the Model-Driven Engineering paradigm, one of the entry requirements when realising a seamless tool chain for the development of software is the definition of metamodels, to regulate the specification of models, and model transformations, for automating manipulations of models. In this context, we present a metamodel definition for the Rubus Component Model, an industrial solution used for the development of vehicular embedded systems. The metamodel includes the definition of structural elements as well as elements for describing timing information. In order to show how, using Model-Driven Engineering, the integration between different modelling levels can be automated, we present a model-to-model transformation between models conforming to EAST-ADL and models described by means of the Rubus Component Model. To validate our solution, we exploit a set of industrial automotive applications to show the applicability of both the Rubus Component Model metamodel and the model transformation.

  • 47.
    Burgin, Mark
    et al.
    UCLA - University of California, Los Angeles, USA .
    Dodig-Crnkovic, Gordana
    Chalmers University of Technology and University of Gothenburg.
    A Taxonomy of Computation and Information Architecture: ECSA 2015 ASDS Workshop. In Proceedings of the 2015 European Conference on Software Architecture Workshops (ECSAW '15). ACM, New York, NY, USA.2015In: 9th European Conference on Software Architecture Workshops ECSAW 2015, 2015, Vol. Article No. 7Conference paper (Refereed)
    Abstract [en]

    This paper presents taxonomy of models of computation. It includes Existential (Physical, Abstract and Cognitive), Organizational, Temporal, Representational, Domain/Data, Operational, Process-oriented and Level-based taxonomy. It is connected to more general notion of natural computation, intrinsic to physical systems, and particularly to cognitive computation in living organisms and artificial cognitive systems. Computation is often understood through the Turing machine model, in the fields of computability, computational complexity and even as a basis for the present-day computer hardware and software architectures. However, several aspects of computation, even those existing in today's applications, are left outside in this model, thus adequate models of real-time, distributed, self-organized, resource-aware, adaptive, learning computation systems are currently being developed.

  • 48.
    Bygde, Stefan
    Mälardalen University, School of Innovation, Design and Engineering.
    Parametric WCET Analysis2013Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In a real-time system, it is crucial to ensure that all tasks of the system hold their deadlines. A missed deadline in a real-time system means that the system has not been able to function correctly. If the system is safety critical, this could potentially lead to disaster. To ensure that all tasks keep their deadlines, the Worst-Case Execution Time (WCET) of these tasks has to be known.

    Static analysis analyses a safe model of the hardware together with the source or object code of a program to derive an estimate of the WCET. This estimate is guaranteed to be equal to or greater than the real WCET. This is done by making calculations which in all steps make sure that the time is exactly or conservatively estimated. In many cases, however, the execution time of a task or a program is highly dependent on the given input. Thus, the estimated worst case may correspond to some input or configuration which is rarely (or never) used in practice. For such systems, where execution time is highly input dependent, a more accurate timing analysis which take input into consideration is desired.

    In this thesis we present a method based on abstract interpretation and counting of semantic states of a program that gives a WCET in terms of some input to the program. This means that the WCET is expressed as a formula of the input rather than a constant. This means that once the input is known, the actual WCET may be more accurate than the absolute and global WCET. Our research also investigate how this analysis can be safe when arithmetic operations causes integers to wrap-around, where the common assumption in static analysis is that variables can take the value of any integer. Our method has been implemented as a prototype and as a part of a static WCET analysis tool in order to get experience with the method and to evaluate the different aspects. Our method shows that it is possible to obtain very complex and detailed information about the timing of a program, given its input.

  • 49.
    Bygde, Stefan
    Mälardalen University, School of Innovation, Design and Engineering.
    Static WCET Analysis Based on Abstract Interpretation and Counting of Elements2010Licentiate thesis, monograph (Other academic)
    Abstract [en]

    In a real-time system, it is crucial to ensure that all tasks of the system holdtheir deadlines. A missed deadline in a real-time system means that the systemhas not been able to function correctly. If the system is safety critical, this canlead to disaster. To ensure that all tasks keep their deadlines, the Worst-CaseExecution Time (WCET) of these tasks has to be known. This can be done bymeasuring the execution times of a task, however, this is inflexible, time consumingand in general not safe (i.e., the worst-casemight not be found). Unlessthe task is measured with all possible input combinations and configurations,which is in most cases out of the question, there is no way to guarantee that thelongest measured time actually corresponds to the real worst case.Static analysis analyses a safe model of the hardware together with thesource or object code of a program to derive an estimate of theWCET. This estimateis guaranteed to be equal to or greater than the real WCET. This is doneby making calculations which in all steps make sure that the time is exactlyor conservatively estimated. In many cases, however, the execution time of atask or a program is highly dependent on the given input. Thus, the estimatedworst case may correspond to some input or configuration which is rarely (ornever) used in practice. For such systems, where execution time is highly inputdependent, a more accurate timing analysis which take input into considerationis desired.In this thesis we present a framework based on abstract interpretation andcounting of possible semantic states of a program. This is a general methodof WCET analysis, which is language independent and platform independent.The two main applications of this framework are a loop bound analysis and aparametric analysis. The loop bound analysis can be used to quickly find upperbounds for loops in a program while the parametric framework provides aninput-dependent estimation of theWCET. The input-dependent estimation cangive much more accurate estimates if the input is known at run-time.

  • 50.
    Bylund, Mathias
    Mälardalen University, School of Innovation, Design and Engineering.
    Evaluation of OKL42009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Virtualization is not a new concept in computer science. It has been used since the middle of the sixties and now software companies has interested in this technology. Virtualization is used in server side to maximize the capacity and reduce power consumption. This thesis focuses on virtualization in embedded system. The technology uses a hypervisor or a virtual machine monitor as a software layer that provide the virtual machine and to isolate the underlying hardware. One of most interesting issue is that is supports several operating system and applications running on the same hardware platform and the hypervisor has complete control of system resources. The company Open Kernel Labs is one of the leading providers of embedded systems software virtualization technology and OKL4 is one of theirproducts, which is based on L4 family of second-generation microkernel’s. In this thesis, we will evaluate the kernel contains, the performance, the security and the environment of the OKL4. Finally we conclude the advantages and disadvantages of the product and technology.

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