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  • 101.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kihl, Maria
    Lund University.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Analysis and characterization of a Video-on-Demand service workload2015Ingår i: Proceedings of the 6th ACM Multimedia Systems Conference, MMSys 2015, ACM Digital Library, 2015, 189-200 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Video-on-Demand (VoD) and video sharing services accountfor a large percentage of the total downstream Internet traf-fic. In order to provide a better understanding of the loadon these services, we analyze and model a workload tracefrom a VoD service provided by a major Swedish TV broad-caster. The trace contains over half a million requests gener-ated by more than 20000 unique users. Among other things,we study the request arrival rate, the inter-arrival time, thespikes in the workload, the video popularity distribution, thestreaming bit-rate distribution and the video duration distri-bution. Our results show that the user and the session ar-rival rates for the TV4 workload does not follow a Poissonprocess. The arrival rate distribution is modeled using a log-normal distribution while the inter-arrival time distributionis modeled using a stretched exponential distribution. Weobserve the “impatient user” behavior where users abandonstreaming sessions after minutes or even seconds of startingthem. Both very popular videos and non-popular videos areparticularly affected by impatient users. We investigate ifthis behavior is an invariant for VoD workloads.

  • 102.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Rezaie, Ali
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Mehta, Amardeep
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Razroev, Stanislav
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Sjöstedt-de Luna, Sara
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Seleznjev, Oleg
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    How will your workload look like in 6 years?: Analyzing Wikimedia's workload2014Ingår i: Proceedings of the 2014 IEEE International Conference on Cloud Engineering (IC2E 2014) / [ed] Lisa O’Conner, IEEE Computer Society, 2014, 349-354 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Accurate understanding of workloads is key to efficient cloud resource management as well as to the design of large-scale applications. We analyze and model the workload of Wikipedia, one of the world's largest web sites. With descriptive statistics, time-series analysis, and polynomial splines, we study the trend and seasonality of the workload, its evolution over the years, and also investigate patterns in page popularity. Our results indicate that the workload is highly predictable with a strong seasonality. Our short term prediction algorithm is able to predict the workload with a Mean Absolute Percentage Error of around 2%.

  • 103.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Seleznjev, Oleg
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Sjöstedt-de Luna, Sara
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Measuring cloud workload burstiness2014Ingår i: 2014 IEEE/ACM 7th International Conference on Utility and Cloud Computing (UCC), IEEE conference proceedings, 2014, 566-572 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Workload burstiness and spikes are among the main reasons for service disruptions and decrease in the Quality-of-Service (QoS) of online services. They are hurdles that complicate autonomic resource management of datacenters. In this paper, we review the state-of-the-art in online identification of workload spikes and quantifying burstiness. The applicability of some of the proposed techniques is examined for Cloud systems where various workloads are co-hosted on the same platform. We discuss Sample Entropy (SampEn), a measure used in biomedical signal analysis, as a potential measure for burstiness. A modification to the original measure is introduced to make it more suitable for Cloud workloads.

  • 104.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kihl, Maria
    Lund University.
    WAC: A Workload analysis and classification tool for automatic selection of cloud auto-scaling methodsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Autoscaling algorithms for elastic cloud infrastructures dynami-cally change the amount of resources allocated to a service ac-cording to the current and predicted future load. Since there areno perfect predictors, no single elasticity algorithm is suitable foraccurate predictions of all workloads. To improve the quality ofworkload predictions and increase the Quality-of-Service (QoS)guarantees of a cloud service, multiple autoscalers suitable for dif-ferent workload classes need to be used. In this work, we intro-duce WAC, a Workload Analysis and Classification tool that as-signs workloads to the most suitable elasticity autoscaler out of aset of pre-deployed autoscalers. The workload assignment is basedon the workload characteristics and a set of user-defined Business-Level-Objectives (BLO). We describe the tool design and its maincomponents. We implement WAC and evaluate its precision us-ing various workloads, BLO combinations and state-of-the-art au-toscalers. Our experiments show that, when the classifier is tunedcarefully, WAC assigns between 87% and 98.3% of the workloadsto the most suitable elasticity autoscaler.

  • 105.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kihl, Maria
    Department of Electrical and Information Technology, Lund University, Lund, Sweden.
    Workload Classification for Efficient Auto-Scaling of Cloud Resources2013Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Elasticity algorithms for cloud infrastructures dynamically change the amount of resources allocated to a running service according to the current and predicted future load. Since there is no perfect predictor, and since different applications’ workloads have different characteristics, no single elasticity algorithm is suitable for future predictions for all workloads. In this work, we introduceWAC, aWorkload Analysis and Classification tool that analyzes workloads and assigns them to the most suitable elasticity controllers based on the workloads’ characteristics and a set of business level objectives.

    WAC has two main components, the analyzer and the classifier. The analyzer analyzes workloads to extract some of the features used by the classifier, namely, workloads’ autocorrelations and sample entropies which measure the periodicity and the burstiness of the workloads respectively. These two features are used with the business level objectives by the clas-sifier as the features used to assign workloads to elasticity controllers. We start by analyzing 14 real workloads available from different applications. In addition, a set of 55 workloads is generated to test WAC on more workload configurations. We implement four state of the art elasticity algorithms. The controllers are the classes to which the classifier assigns workloads. We use a K nearest neighbors classifier and experiment with different workload combinations as training and test sets. Our experi-ments show that, when the classifier is tuned carefully, WAC correctly classifies between 92% and 98.3% of the workloads to the most suitable elasticity controller.

  • 106.
    Ali-Eldin Hassan, Ahmed
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Workload characterization, controller design and performance evaluation for cloud capacity autoscaling2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis studies cloud capacity auto-scaling, or how to provision and release re-sources to a service running in the cloud based on its actual demand using an auto-matic controller. As the performance of server systems depends on the system design,the system implementation, and the workloads the system is subjected to, we focuson these aspects with respect to designing auto-scaling algorithms. Towards this goal,we design and implement two auto-scaling algorithms for cloud infrastructures. Thealgorithms predict the future load for an application running in the cloud. We discussthe different approaches to designing an auto-scaler combining reactive and proactivecontrol methods, and to be able to handle long running requests, e.g., tasks runningfor longer than the actuation interval, in a cloud. We compare the performance ofour algorithms with state-of-the-art auto-scalers and evaluate the controllers’ perfor-mance with a set of workloads. As any controller is designed with an assumptionon the operating conditions and system dynamics, the performance of an auto-scalervaries with different workloads.In order to better understand the workload dynamics and evolution, we analyze a6-years long workload trace of the sixth most popular Internet website. In addition,we analyze a workload from one of the largest Video-on-Demand streaming servicesin Sweden. We discuss the popularity of objects served by the two services, the spikesin the two workloads, and the invariants in the workloads. We also introduce, a mea-sure for the disorder in a workload, i.e., the amount of burstiness. The measure isbased on Sample Entropy, an empirical statistic used in biomedical signal processingto characterize biomedical signals. The introduced measure can be used to charac-terize the workloads based on their burstiness profiles. We compare our introducedmeasure with the literature on quantifying burstiness in a server workload, and showthe advantages of our introduced measure.To better understand the tradeoffs between using different auto-scalers with differ-ent workloads, we design a framework to compare auto-scalers and give probabilisticguarantees on the performance in worst-case scenarios. Using different evaluation cri-teria and more than 700 workload traces, we compare six state-of-the-art auto-scalersthat we believe represent the development of the field in the past 8 years. Knowingthat the auto-scalers’ performance depends on the workloads, we design a workloadanalysis and classification tool that assigns a workload to its most suitable elasticitycontroller out of a set of implemented controllers. The tool has two main components;an analyzer, and a classifier. The analyzer analyzes a workload and feeds the analysisresults to the classifier. The classifier assigns a workload to the most suitable elasticitycontroller based on the workload characteristics and a set of predefined business levelobjectives. The tool is evaluated with a set of collected real workloads, and a set ofgenerated synthetic workloads. Our evaluation results shows that the tool can help acloud provider to improve the QoS provided to the customers.

  • 107.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Towards Automatic Ontology Alignmentfor Enriching Sensor Data Analysis2013Ingår i: Communications in Computer and Information Science, ISSN 1865-0929, E-ISSN 1865-0937, Vol. 415, 179-193 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work ontology alignment is used to align an ontology comprising high level knowledge to a structure representing the results of low-level sensor data classification. To resolve inherent uncertainties from the data driven classifier, an ontology about application domain is aligned to the classifier output and the result is recommendation system able to suggest a course of action that will resolve the uncertainty. This work is instantiated in a medical application domain where signals from an electronic nose are classified into different bacteria types. In case of misclassifications resulting from the data driven classifier, the alignment to an ontology representing traditional microbiology tests suggests a subset of tests most relevant to use. The result is a hybrid classification system (electronic nose and traditional testing) that automatically exploits domain knowledge in the identification process.

  • 108.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Pecora, Federico
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Context Recognition: Towards Automatic Query Generation2015Ingår i: Ambient Intelligence: 12th European Conference, AmI 2015, Athens, Greece, November 11-13, 2015, Proceedings, Springer, 2015, 205-218 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present an ontology-based approach in designing knowledge model for context recognition (CR) systems. The main focus in this paper is on the use of an ontology to facilitate the generation of user-based queries to the CR system. By leveraging from the ontology, users need not know about sensor details and the structure of the ontology in expressing queries related to events of interest. To validate the approach and demonstrate the flexibility of the ontology for query generation, the ontology has been integrated in two separate application domains. The first domain considers a health care system implemented for the GiraffPlus project where the query generation process is automated to request information about activities of daily living. The second application uses the same ontology for an air quality monitoring application in the home. Since these two systems are independently developed for different purposes, the ease of applying the ontology upon them can be considered as a credit for its generality.

  • 109.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Renoux, Jennifer
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Köckemann, Uwe
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kristoffersson, Annica
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Karlsson, Lars
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Blomqvist, Eva
    RISE SICS East, Linköping, Sweden.
    Tsiftes, Nicolas
    RISE SICS, Stockholm, Sweden.
    Voigt, Thiemo
    RISE SICS, Stockholm, Sweden.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    An Ontology-based Context-aware System for Smart Homes: E-care@home2017Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, nr 7, 1586Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

  • 110.
    Alm, Anton
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Björling, Joakim
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Prestandautvärdering av firmwares baserade på öppen källkod för routrar/brandväggar på MIPS-arkitektur: Jämförelse mellan Open-WRT, DD-WRT och Tomato firmware2014Självständigt arbete på grundnivå (högskoleexamen), 80 poäng / 120 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den här undersökningen jämför prestanda hos tre olika firmwares som är baserade på öppen källkod. DD-WRT, Open-WRT samt Tomato Firmware för MIPS-arkitektur. Testerna följer två RFC som beskriver hur en prestandaanalys av ett nätverk ska genomföras.

    De sammanfattade resultaten pekar på en vinnare som presterat generellt bättre genom alla tester och det var Tomato firmware. Dessa resultat är hämtade från tre olika tester: genomströmningstest, svarstidstest och test med samtidiga sessioner.

    Undersökningen visar också att prestandan rent generellt är väldigt jämlik över alla firmwares i de olika testerna. En viktig aspekt är att det finns ingen överlägsen vinnare, vilket beror på, till exempel, hur konsekventa resultaten varit. Detta hänger även ihop med en möjlig slutsats där firmwaresen presterar olika bra beroende på vilken typ av uppgift det gäller.

    Som fortsatt arbete rekommenderas prestanda och funktionsanalys av liknande verktyg som varje firmware innehåller. Även en undersökning gällande gränssnittet för varje firmware skulle vara intressant.

  • 111.
    Almgren, David
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Alshammari, Hussam
    Högskolan i Halmstad, Akademin för informationsteknologi.
    SmartBand Alert: Ett armband för säkerhet2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Safety is a topic that is frequently discussed and spoken of in today’s society. An enhanced security for each individual is something many strive for in various industries. One of these is how to make the public feel more secure when the person in question, for example, is out walking late at night. The goal of this bachelors thesis is thus to describe and explain the product that has been developed to get ordinary people to feel more secure wherever they are. The chosen solution for this issue was hence to develop the product SmartBand Alert which consists of two parts. A bracelet and an application for IOS and Android. This bracelet should, by certain connectivity cooperate with the user’s phone to notify family members and/or others when the person thinks or knows that he or she is in danger. These persons will be notified with information about the person who has activated the alarm to simply and easily take the necessary actions to help the person. The product is designed to be used by anyone regardless of gender, age, and other characteristics individuals may hold.

  • 112.
    Almquist, Mathias
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Almquist, Viktor
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    A study on Android games: 3G energy consumption, CPU-utilization and system calls2015Självständigt arbete på grundnivå (högskoleexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The popularity of mobile games has increased drastically during the recent years andmany people use them as their main source of entertainment. Mobile gamescommunicate with other devices over the network which consumes a lot of energy,especially when connected to cellular networks (e.g., 3G). This high energy expensecan feel unjustified to the player since always-on network connectivity is not requiredin order to play most games.Furthermore, the number of malware-infected applications in offical applicationstores has increased significantly in the recent years. These malware-infectedapplications can gain unrestricted access and control of users phones which can be athreat to security. Information about the behaviour characteristics of games can beused to develop or improve systems for detecting malware applications.In this thesis, 20 popular Android games are analysed with a focus on the datacommunication, CPU utilization and system call behaviour. The main subject of thedata communication study is the 3G communication energy consumed by games. Thesystem call study aims at quantifying the number and type of calls used by games.This may be useful in a further study of harmful behaviour by apps.The profiling results presented in this report show that the communication energyvaries drastically among games. Games with a very similar gameplay can consumevery different amounts of energy which indicates that there is room for improvementsin many of the games. Ad-free games consume significantly less energy than gamesthat use in-app advertisements. The results show that improving the advertisementfetching policy could reduce the energy consumption of these games. The majority ofthe games can be played without network connectivity and therefore thecommunication energy consumed could be completely avoided. The thesis alsoshows that games use a wide variety of system calls and that many of the system callsare common among the games.

  • 113.
    Almér, Alexander
    et al.
    Chalmers University of Technology and Gothenburg University, Sweden.
    von Hautwitz, Rickard
    Chalmers University of Technology and Gothenburg University, Sweden.
    Dodig-Crnkovic, Gordana
    Chalmers University of Technology and Gothenburg University, Sweden.
    Collective Cognition and Distributed Information Processing from Bacteria to Humans: Proc. AISB Conference Kent 2015.2015Ingår i: 41st Annual Convention of the Society for the Study of Artificial Intelligence and the Simulation of Behaviour: (AISB 2015), 2015, 119-124 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of this paper is to propose a general infocomputational model of cognition that can be applied to living organisms from the level of a single cell´s cognition to the level of groups of increasingly complex organisms with social, distributed cognition. We defend the project of new cognitivism, which unlike the old one acknowledges the central role of embodiment for cognition. Information processing going on in a cognising agent range from transduction of chemical signals and “quorum sensing” in bacteria, via simple local rules of behaviour that insects follow and that manifest themselves as “swarm intelligence”, to human level cognition with full richness of human languages and other systems of communication.

  • 114.
    Alnervik, Erik
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Evaluation of the Configurable Architecture REPLICA with Emulated Shared Memory2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    REPLICA är en grupp av konfigurerbara multiprocessorer som med hjälp utav ett emulerat delat minne realiserar PRAM modellen.

    Syftet med denna avhandling är att genom benchmarking av olika beräkningsproblem på REPLICA, liknande (SB-PRAM och XMT) och mindre lika (Xeon X5660 och Tesla M2050) parallella arkitekturer, utvärdera hur REPLICA står sig mot andra befintliga arkitekturer. Både prestandamässigt och hur enkel arkitekturen är att programmera effektiv, men även försöka ta reda på om REPLICA är speciellt lämpad för några särskilda typer av beräkningsproblem.

    Genom att använda välkända Berkeley dwarfs applikationer och opartisk indata från bland annat The University of Florida Sparse Matrix Collection och Rodinia benchmark suite, säkerställer vi att det är relevanta beräkningsproblem som utförs och mäts.

    Vi visar att dagens parallella arkitekturer har problem med prestandan för applikationer med oregelbundna minnesaccessmönster, vilken REPLICA arkitekturen kan vara en lösning på. Till exempel, så behöver REPLICA endast vara klockad med några få MHz för att matcha både Xeon X5660 och Tesla M2050 för algoritmen breadth first search, vilken lider av just oregelbunden minnesåtkomst. Genom att jämföra effektiviteten för REPLICA gentemot en CPU (Xeon X5660), visar vi att det är lättare att programmera REPLICA effektivt än dagens multiprocessorer.

  • 115.
    Aloisi, Alessandro
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem. University of Bologna (Italy).
    Enabling communication between Wireless Sensor Networks and The Internet-of-Things: A CoAP communication stack2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The thesis focuses on enabling the communication between Wireless Sensor Networks and Internet-of-Things applications.  In order to achieve this goal, the first step has been to investigate the concept of the Internet-of-Things and then to understand how this scenario could be used to interconnect multiple Wireless Sensor Networks in order to develop context-aware applications which could handle sensor data coming from this type of network. 

    The second step was to design and implement a communication stack which enabled Wireless Sensor Networks to communicate with an Internet-of-Things platform. The CoAP protocol has been used as application protocol for the communication with the Wireless Sensor Networks. The solution has been developed in Java programming language and extended the sensor and actuator layer of the Sensible Things platform. 

    The third step of this thesis has been to investigate in which real world applications the developed solution could have been used. Next a Proof of Concept application has been implemented in order to simulate a simple fire detection system, where multiple Wireless Sensor Networks collaborate to send their temperature data to a control center. The last step was to evaluate the whole system, specifically the responsiveness and the overhead introduced by the developed communication stack.

  • 116.
    Al-Otaibi, Ahmad
    et al.
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Data- och elektroteknik.
    Hamed Oraibi, Yaser
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Data- och elektroteknik.
    AUTOMOTIVE BUS SYSTEM SCALABILITY2015Självständigt arbete på grundnivå (kandidatexamen), 180 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Sammanfattning

    Syfte: syftet med studien var att skapa en djupare förståelse om CAN-FD och hur den fungerar med Partial Network.

    Metod: Studien är en allmän litteraturstudie som är baserad på facklitteratur, datablad och intervju.

    Resultat: Studien visade att skalbarheten skiljde sig inte mellan CAN och CAN-FD. De största skillnader var hastigheten och datamängd mellan protokollen. Studien fann även att CAN-FD inte fungerade med Partial Network.

    Implikationer: Denna litteraturstudie är en bra introduktion och förhållning till företag som intresserar sig av CAN-FD. Studien kan bidra till ökat kunskap hos företagen om CAN-FD.

    Begränsningar: En kvantitativ metod skulle vara en användbar metod att utföra studien med. Detta skulle ge verkliga resultat som kan baserar på litteratur som använts i föreliggande studie. Ett problem som författarna upplevde var brist på vetenskaplig forskning om CAN-FD. Av den anledningen kan författarna inte dra en ren slutsats. 

  • 117.
    Al-Shishtawy, Ahmad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    Self-Management for Large-Scale Distributed Systems2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Autonomic computing aims at making computing systems self-managing by using autonomic managers in order to reduce obstacles caused by management complexity. This thesis presents results of research on self-management for large-scale distributed systems. This research was motivated by the increasing complexity of computing systems and their management.

    In the first part, we present our platform, called Niche, for programming self-managing component-based distributed applications. In our work on Niche, we have faced and addressed the following four challenges in achieving self-management in a dynamic environment characterized by volatile resources and high churn: resource discovery, robust and efficient sensing and actuation, management bottleneck, and scale. We present results of our research on addressing the above challenges. Niche implements the autonomic computing architecture, proposed by IBM, in a fully decentralized way. Niche supports a network-transparent view of the system architecture simplifying the design of distributed self-management. Niche provides a concise and expressive API for self-management. The implementation of the platform relies on the scalability and robustness of structured overlay networks. We proceed by presenting a methodology for designing the management part of a distributed self-managing application. We define design steps that include partitioning of management functions and orchestration of multiple autonomic managers.

    In the second part, we discuss robustness of management and data consistency, which are necessary in a distributed system. Dealing with the effect of churn on management increases the complexity of the management logic and thus makes its development time consuming and error prone. We propose the abstraction of Robust Management Elements, which are able to heal themselves under continuous churn. Our approach is based on replicating a management element using finite state machine replication with a reconfigurable replica set. Our algorithm automates the reconfiguration (migration) of the replica set in order to tolerate continuous churn. For data consistency, we propose a majority-based distributed key-value store supporting multiple consistency levels that is based on a peer-to-peer network. The store enables the tradeoff between high availability and data consistency. Using majority allows avoiding potential drawbacks of a master-based consistency control, namely, a single-point of failure and a potential performance bottleneck.

    In the third part, we investigate self-management for Cloud-based storage systems with the focus on elasticity control using elements of control theory and machine learning. We have conducted research on a number of different designs of an elasticity controller, including a State-Space feedback controller and a controller that combines feedback and feedforward control. We describe our experience in designing an elasticity controller for a Cloud-based key-value store using state-space model that enables to trade-off performance for cost. We describe the steps in designing an elasticity controller. We continue by presenting the design and evaluation of ElastMan, an elasticity controller for Cloud-based elastic key-value stores that combines feedforward and feedback control.

  • 118.
    Al-Shishtawy, Ahmad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster, Programvaru- och datorsystem, SCS.
    Fayyaz, Muhammad Asif
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster, Programvaru- och datorsystem, SCS.
    Popov, Konstantin
    Swedish Institute of Computer Science (SICS), Kista, Sweden.
    Vlassov, Vladimir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster, Programvaru- och datorsystem, SCS.
    Achieving Robust Self-Management for Large-Scale Distributed Applications2010Ingår i: Self-Adaptive and Self-Organizing Systems (SASO), 2010 4th IEEE International Conference on: SASO 2010, IEEE Computer Society, 2010, 31-40 s.Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Achieving self-management can be challenging, particularly in dynamic environments with resource churn (joins/leaves/failures). Dealing with the effect of churn on management increases the complexity of the management logic and thus makes its development time consuming and error prone. We propose the abstraction of robust management elements (RMEs), which are able to heal themselves under continuous churn. Using RMEs allows the developer to separate the issue of dealing with the effect of churn on management from the management logic. This facilitates the development of robust management by making the developer focus on managing the application while relying on the platform to provide the robustness of management. RMEs can be implemented as fault-tolerant long-living services. We present a generic approach and an associated algorithm to achieve fault-tolerant long-living services. Our approach is based on replicating a service using finite state machine replication with a reconfigurable replica set. Our algorithm automates the reconfiguration (migration) of the replica set in order to tolerate continuous churn. The algorithm uses P2P replica placement schemes to place replicas and uses the P2P overlay to monitor them. The replicated state machine is extended to analyze monitoring data in order to decide on when and where to migrate. We describe how to use our approach to achieve robust management elements. We present a simulation-based evaluation of our approach which shows its feasibility.

  • 119.
    Al-Shishtawy, Ahmad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    Vlassov, Vladimir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    ElastMan: Autonomic Elasticity Manager for Cloud-Based Key-Value Stores2012Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The increasing spread of elastic Cloud services, together with the pay-asyou-go pricing model of Cloud computing, has led to the need of an elasticity controller. The controller automatically resizes an elastic service, in response to changes in workload, in order to meet Service Level Objectives (SLOs) at a reduced cost. However, variable performance of Cloud virtual machines and nonlinearities in Cloud services, such as the diminishing reward of adding a service instance with increasing the scale, complicates the controller design. We present the design and evaluation of ElastMan, an elasticity controller for Cloud-based elastic key-value stores. ElastMan combines feedforward and feedback control. Feedforward control is used to respond to spikes in the workload by quickly resizing the service to meet SLOs at a minimal cost. Feedback control is used to correct modeling errors and to handle diurnal workload. To address nonlinearities, our design of ElastMan leverages the near-linear scalability of elastic Cloud services in order to build a scale-independent model of the service. Our design based on combining feedforward and feedback control allows to efficiently handle both diurnal and rapid changes in workload in order to meet SLOs at a minimal cost. Our evaluation shows the feasibility of our approach to automation of Cloud service elasticity.

  • 120.
    Al-Shishtawy, Ahmad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    Vlassov, Vladimir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    ElastMan: Autonomic elasticity manager for cloud-based key-value stores2013Ingår i: HPDC 2013 - Proceedings of the 22nd ACM International Symposium on High-Performance Parallel and Distributed Computing, 2013, 115-116 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The increasing spread of elastic Cloud services, together with the pay-as-you-go pricing model of Cloud computing, has led to the need of an elasticity controller. The controller automatically resizes an elastic service in response to changes in workload, in order to meet Service Level Objectives (SLOs) at a reduced cost. However, variable performance of Cloud virtual machines and nonlinearities in Cloud services complicates the controller design. We present the design and evaluation of ElastMan, an elasticity controller for Cloud-based elastic key-value stores. ElastMan combines feedforward and feedback control. Feedforward control is used to respond to spikes in the workload by quickly resizing the service to meet SLOs at a minimal cost. Feedback control is used to correct modeling errors and to handle diurnal workload. We have implemented and evaluated ElastMan using the Voldemort key-value store running in a Cloud environment based on OpenStack. Our evaluation shows the feasibility and effectiveness of our approach to automation of Cloud service elasticity.

  • 121.
    Al-Shishtawy, Ahmad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    Vlassov, Vladimir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    ElastMan: Elasticity manager for elastic key-value stores in the cloud2013Ingår i: Proceedings of the 2013 ACM Cloud and Autonomic Computing Conference, New York, NY, USA: Association for Computing Machinery (ACM), 2013, 7:1-7:10 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The increasing spread of elastic Cloud services, together with the pay-as-you-go pricing model of Cloud computing, has led to the need of an elasticity controller. The controller automatically resizes an elastic service in response to changes in workload, in order to meet Service Level Objectives (SLOs) at a reduced cost. However, variable performance of Cloud Virtual Machines and nonlinearities in Cloud services, such as the diminishing reward of adding a service instance with increasing the scale, complicates the controller design. We present the design and evaluation of ElastMan, an elasticity controller for Cloud-based elastic key-value stores. ElastMan combines feedforward and feedback control. Feedforward control is used to respond to spikes in the workload by quickly resizing the service to meet SLOs at a minimal cost. Feedback control is used to correct modeling errors and to handle diurnal workload. To address nonlinearities, our design of ElastMan leverages the near-linear scalability of elastic Cloud services in order to build a scale-independent model of the service. We have implemented and evaluated ElastMan using the Voldemort key-value store running in an OpenStack Cloud environment. Our evaluation shows the feasibility and effectiveness of our approach to automation of Cloud service elasticity.

  • 122.
    Altenbernd, Peter
    et al.
    University of Applied Sciences Darmstadt, Germany.
    Ermedahl, Andreas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Lisper, Björn
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gustafsson, Jan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Automatic Generation of Timing Models for Timing Analysis of High-Level Code2011Ingår i: 19th International Conference on Real-Time and Network Systems (RTNS2011), 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Traditional timing analysis is applied only in the late stages of embedded system software development, when the hardware is available and the code is compiled and linked. However, preliminary timing estimates are often needed already in early stages of system development, both for hard and soft real-time systems. If the hardware is not yet fully accessible, or the code is not yet ready to compile or link, then the timing estimation must be done for the source code rather than for the binary. This paper describes how source-level timing models can be derived automatically for given combinations of hardware architecture and compiler. The models are identified from measured execution times for a set of synthetic "training programs" compiled for the hardware platform in question. The models can be used to derive source-level WCET estimates, as well as for estimating the execution times for single program runs. Our experiments indicate that the models can predict the execution times of the final, compiled code with a deviation up to 20%.

  • 123.
    Altenbernd, Peter
    et al.
    University of Applied Sciences, Germany.
    Gustafsson, Jan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lisper, Björn
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Stappert, Friedhelm
    Siemens VDO Automotive AG, Germany.
    Early execution time-estimation through automatically generated timing models2016Ingår i: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 52, nr 6, 731-760 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional timing analysis, such as worst-case execution time analysis, is normally applied only in the late stages of embedded system software development, when the hardware is available and the code is compiled and linked. However, preliminary timing estimates are often needed in early stages of system development as an essential prerequisite for the configuration of the hardware setup and dimensioning of the system. During this phase the hardware is often not available, and the code might not be ready to link. This article describes an approach to predict the execution time of software through an early, source-level timing analysis. A timing model for source code is automatically derived from a given combination of hardware architecture and compiler. The model is identified from measured execution times for a set of synthetic training programs, compiled for the hardware platform in question. It can be used to estimate the execution time for code running on the platform: the estimation is then done directly from the source code, without compiling and running it. Our experiments show that, using this model, we can predict the execution times of the final, compiled code surprisingly well. For instance, we achieve an average deviation of 8 % for a set of benchmark programs for the ARM7 architecture.

  • 124.
    Al-Trad, Anas
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Optimized Composition of Parallel Components on a Linux Cluster2012Självständigt arbete på avancerad nivå (masterexamen), 30 poäng / 45 hpStudentuppsats (Examensarbete)
    Abstract [en]

    We develop a novel framework for optimized composition of explicitly parallel software components with different implementation variants given the problem size, data distribution scheme and processor group size on a Linux cluster. We consider two approaches (or two cases of the framework). 

    In the first approach, dispatch tables are built using measurement data obtained offline by executions for some (sample) points in the ranges of the context properties. Inter-/extrapolation is then used to do actual variant-selection for a given execution context at run-time.

    In the second approach, a cost function of each component variant is provided by the component writer for variant-selection. These cost functions can internally lookup measurements' tables built, either offline or at deployment time, for computation- and communication-specific primitives.

    In both approaches, the call to an explicitly parallel software component (with different implementation variants) is made via a dispatcher instead of calling a variant directly.

    As a case study, we apply both approaches on a parallel component for matrix multiplication with multiple implementation variants. We implemented our variants using Message Passing Interface (MPI). The results show the reduction in execution time for the optimally composed applications compared to applications with hard-coded composition. In addition, the results show the comparison of estimated and measured times for each variant using different data distributions, processor group and problem sizes.

  • 125.
    Alvaro, Alexandre
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Land, Rikard
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Crnkovic, Ivica
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Software Component Evaluation: A Theoretical Study on Component Selection and Certification2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Software components need to be evaluated at several points during their life cycle, by different actors and for different purposes. Besides the quality assurance performed by component developers, there are two main activities which include evaluation of components: component selection (i.e. evaluation performed by the system developer in order to select the best fit component to use in a system) and an envisioned component certification (i.e. evaluation made by an independent actor in order to increase the trust in the component). This paper examines the fundamental similarities and differences between these two types of component evaluations and elaborates how these fit in the overall process views of component-based development for both COTS-based development and software product line development.

  • 126.
    Alveflo, Victor
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Virtual Training Tool: Mjukvarubaserat utbildningsverktyg2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    En viktig del hos företag som tillverkar diverse industrimaskiner är att utbilda den personal som förväntas använda och underhålla maskinerna. Detta är för att ge användaren en god förståelse för hur maskinen i fråga fungerar och är uppbyggd. Vid sådana utbildningar är det viktigt att tillhandahålla användarvänligt utbildnings-material.

    Målet med detta examensarbete är att förbättra användarvänligheten för utbildningsmaterialet hos en viss utbildning för projektets uppdragsgivare. Den utbildning som skall förbättras går i dagsläget ut på att manuellt simulera processer hos en specifik maskin via en hårdvarubaserad simuleringsmiljö.

    Resultatet blev en lösning i form av en mjukvarubaserad simulator med tillhörande grafiskt användargränssnitt. Användaren kan därigenom på ett säkert sätt simulera maskinens beteende genom ett PC-program och då t.ex. skapa nödsituationer utan att användarens säkerhet sätts i fara.

  • 127.
    Alvila, Markus
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Johansson, Jonathan
    Linköpings universitet, Institutionen för datavetenskap.
    Johansson, Philip
    Linköpings universitet, Institutionen för datavetenskap.
    Lenz, Silas
    Linköpings universitet, Institutionen för datavetenskap.
    Lindmark, Sebastian
    Linköpings universitet, Institutionen för datavetenskap.
    Norberg, Emil
    Linköpings universitet, Institutionen för datavetenskap.
    Regard, Viktor
    Linköpings universitet, Institutionen för datavetenskap.
    Övervakning och bedömning av flygledares prestanda2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 128.
    Amatya, Suyesh
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Kurti, Arianit
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Cross-Platform Mobile Development: Challenges and Opportunities2013Ingår i: ICT Innovations 2013: ICT Innovations and Education / [ed] Vladimir Trajkovik and Misev Anastas, Springer, 2013, 1, 219-229 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Mobile devices and mobile computing have made tremendous advances and become ubiquitous in the last few years. As a result, the landscape has become seriously fragmented which brings lots of challenges for the mobile development process. Whilst native approach of mobile development still is the predominant way to develop for a particular mobile platform, recently there is shifting towards cross-platform mobile development as well. In this paper, we have performed a survey of the literature to see the trends in cross-platform mobile development over the last few years. With the result of the survey, we argue that the web-based approach and in particular,hybrid approach, of mobile development serves the best for cross-platform development. The results of this work indicate that even though cross platform tools are not fully matured they show great potential. Thus we consider that cross-platform development offers great opportunities for rapid development of high-fidelity prototypes of the mobile application.

  • 129.
    AMEEN HASHIM, FARHAN
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Al Eid, Jamal
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Al-Salem, Abdulkhaliq
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Comparing of Real-Time Properties in Networks Based On IPv6 and IPv42013Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Real time applications over IP network became widely used in different fields; social video conference, online educational lectures, industrial, military, and online robotic medical surgery.

    Online medical surgery over IP network has experienced rapid growth in the last few years primarily due to advances in technology (e.g., increased bandwidth; new cameras, monitors, and coder/decoders (CODECs)) and changes in the medical care environment (e.g., increased outpatient care, remote surgeries).

    The purpose of this study was to examine and analyze the impact of IP networks parameters; delay, jitter, throughput, and drop packet on the performance of real-time medical surgery videos sent across different IP networks; native IPv6, native IPv4, 6to4 and 6in4 tunneling transition mechanisms and compare the behavior of video packets over IP networks. The impact of each parameter over IP networks is examined by using different video codecs MPEG-1, MPEG-2, and MPEG-4.

    This study has been carried out with two main parts; theoretical and practical part, the theoretical part of this study focused on the calculations of various delays in IP networks such as transmission, processing, propagation, and queuing delays for video packet, while the practical part includes; examining of video codecs throughput over IP networks by using jperf tool and examining delay, jitter, and packet drops for different packet sizes by using IDT-G tool and how these parameters can affect quality of received video.

    The obtained theoretical and practical results were presented in different tables and plotted into different graphs to show the performance of real time video over IP networks. These results confirmed that video codecs MPEG-1, MPEG-2, and MPEG-4 were highly impacted by encapsulation and de-capsulation process except MPEG-4 codec, MPEG-4 was the least impacted by IPv4, IPv6, and IP transition mechanisms concerning throughput and wastage bandwidth. It also indicated that using IPv6-to-4 and IPv6-in-4 tunneling mechanisms caused more bandwidth wastage, high delay, jitter, and packet drop than IPv4 and IPv6.

  • 130.
    Amighi, Afshin
    et al.
    University of Twente.
    de Carvalho Gomes, Pedro
    KTH, Skolan för datavetenskap och kommunikation (CSC), Teoretisk datalogi, TCS.
    Gurov, Dilian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Teoretisk datalogi, TCS.
    Huisman, Marieke
    University of Twente.
    Provably Correct Control-Flow Graphs from Java Programs with Exceptions2012Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We present an algorithm to extract flow graphs from Java bytecode, including exceptional control flows. We prove its correctness, meaning that the behavior of the extracted control-flow graph is a sound over-approximation of the behavior of the original program. Thus any safety property that holds for the extracted control-flow graph also holds for the original program. This makes control-flow graphs suitable for performing various static analyses, such as model checking.The extraction is performed in two phases. In the first phase the program is transformed into a BIR program, a stack-less intermediate representation of Java bytecode, from which the control-flow graph is extracted in the second phase. We use this intermediate format because it results in compact flow graphs, with provably correct exceptional control flow. To prove the correctness of the two-phase extraction, we also define an idealized extraction algorithm, whose correctness can be proven directly. Then we show that the behavior of the control-flow graph extracted via the intermediate representation is an over-approximation of the behavior of the directly extracted graphs, and thus of the original program. We implemented the indirect extraction as the CFGEx tool and performed several test-cases to show the efficiency of the algorithm.

  • 131.
    Amighi, Afshin
    et al.
    University of Twente.
    de Carvalho Gomes, Pedro
    KTH, Skolan för datavetenskap och kommunikation (CSC), Teoretisk datalogi, TCS.
    Gurov, Dilian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Teoretisk datalogi, TCS.
    Huisman, Marieke
    University of Twente.
    Sound Control-Flow Graph Extraction for Java Programs with Exceptions2012Ingår i: Software Engineering and Formal Methods: 10th International Conference, SEFM 2012, Thessaloniki, Greece, October 1-5, 2012. Proceedings, Springer Berlin/Heidelberg, 2012, 33-47 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present an algorithm to extract control-flow graphs from Java bytecode, considering exceptional flows. We then establish its correctness: the behavior of the extracted graphs is shown to be a sound over-approximation of the behavior of the original programs. Thus, any temporal safety property that holds for the extracted control-flow graph also holds for the original program. This makes the extracted graphs suitable for performing various static analyses, in particular model checking. The extraction proceeds in two phases. First, we translate Java bytecode into BIR, a stack-less intermediate representation. The BIR transformation is developed as a module of Sawja, a novel static analysis framework for Java bytecode. Besides Sawja’s efficiency, the resulting intermediate representation is more compact than the original bytecode and provides an explicit representation of exceptions. These features make BIR a natural starting point for sound control-flow graph extraction. Next, we formally define the transformation from BIR to control-flow graphs, which (among other features) considers the propagation of uncaught exceptions within method calls. We prove the correctness of the two-phase extraction by suitably combining the properties of the two transformations with those of an idealized control-flow graph extraction algorithm, whose correctness has been proved directly. The control-flow graph extraction algorithm is implemented in the ConFlEx tool. A number of test-cases show the efficiency and the utility of the implementation.

  • 132.
    Aminifar, Amir
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Analysis, Design, and Optimization of Embedded Control Systems2016Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Today, many embedded or cyber-physical systems, e.g., in the automotive domain, comprise several control applications, sharing the same platform. It is well known that such resource sharing leads to complex temporal behaviors that degrades the quality of control, and more importantly, may even jeopardize stability in the worst case, if not properly taken into account.

    In this thesis, we consider embedded control or cyber-physical systems, where several control applications share the same processing unit. The focus is on the control-scheduling co-design problem, where the controller and scheduling parameters are jointly optimized. The fundamental difference between control applications and traditional embedded applications motivates the need for novel methodologies for the design and optimization of embedded control systems. This thesis is one more step towards correct design and optimization of embedded control systems.

    Offline and online methodologies for embedded control systems are covered in this thesis. The importance of considering both the expected control performance and stability is discussed and a control-scheduling co-design methodology is proposed to optimize control performance while guaranteeing stability. Orthogonal to this, bandwidth-efficient stabilizing control servers are proposed, which support compositionality, isolation, and resource-efficiency in design and co-design. Finally, we extend the scope of the proposed approach to non-periodic control schemes and address the challenges in sharing the platform with self-triggered controllers. In addition to offline methodologies, a novel online scheduling policy to stabilize control applications is proposed.

  • 133.
    Aminifar, Amir
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Self-Triggered Controllers, Resource Sharing, and Hard Guarantees2016Ingår i: 2016 2ND INTERNATIONAL CONFERENCE ON EVENT-BASED CONTROL, COMMUNICATION, AND SIGNAL PROCESSING (EBCCSP), IEEE , 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today, many control applications in embedded and cyber-physical systems are implemented on shared platforms, alongside other hard real-time or safety-critical applications. Having the resource shared among several applications, to provide hard guarantees, it is required to identify the amount of resource needed for each application. This is rather straightforward when the platform is shared among periodic control and periodic real-time applications. In the case of event-triggered and self-triggered controllers, however, the execution patterns and, in turn, the resource usage are not clear. Therefore, a major implementation challenge, when the platform is shared with self-triggered controllers, is to provide hard and efficient stability and schedulability guarantees for other applications. In this paper, we identify certain execution patterns for self-triggered controllers, using which we are able to provide hard and efficient stability guarantees for periodic control applications.

  • 134.
    Amlinger, Anton
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    An Evaluation of Clustering and Classification Algorithms in Life-Logging Devices2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Using life-logging devices and wearables is a growing trend in today’s society. These yield vast amounts of information, data that is not directly overseeable or graspable at a glance due to its size. Gathering a qualitative, comprehensible overview over this quantitative information is essential for life-logging services to serve its purpose.

    This thesis provides an overview comparison of CLARANS, DBSCAN and SLINK, representing different branches of clustering algorithm types, as tools for activity detection in geo-spatial data sets. These activities are then classified using a simple model with model parameters learned via Bayesian inference, as a demonstration of a different branch of clustering.

    Results are provided using Silhouettes as evaluation for geo-spatial clustering and a user study for the end classification. The results are promising as an outline for a framework of classification and activity detection, and shed lights on various pitfalls that might be encountered during implementation of such service.

  • 135.
    Amoura, Jonas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    Nätverksemulatorer: Nätverksemulering i utbildningssyfte2015Självständigt arbete på grundnivå (högskoleexamen), 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This is a project that deals with network emulators for training purposes, where everything is based on open-source applications. The goal of this project was to evaluate GNS3 and CORE emulators and answer the question, if and how they can be used in educational purposes for students and teachers. The study begins by briefly describing the various emulators available through open-source, where it was chosen to focus on the following network emulators IMUNES: Marionnet, Mininet, NetKit, GNS3 and CORE. The evaluation was conducted using a form, and GNS3 and CORE emulators run on a Linux-based operating systems to test all functions and various applications available within the tools. The results showed that both emulators work great to make use of open-source applications that can emulate router functions to emulate network topologies with different routing protocols such as RIP, OSPF and BGP. The evaluation also showed that both emulators are excellent tools to be used by people with minimal knowledge in programming, because of its user-friendly interface that helps one to build complex topologies using drag-and-drop functionality only. The conclusion of the study is that both emulators work well for educational purposes to develop network technology, router protocols and Linux skills for students, as well as to create a virtual environment to develop their skills with which they also can experiment with their skills. To install the network emulators GNS3 and CORE and related applications took about 30 minutes per tool, as well as taking GNS3 23 MB and Core 10MB hard disk space to be installed without any accessory applications.

    Why these two tools work well for training purposes is that both emulators has integrated support for a large numbers of applications and the use of simple user interface to emulate network environments. In addition, the tools are completely free to all students and teachers, therefore everyone have the same opportunities to access them. The report recommendation is to use the emulator CORE precisely because the utility has so many features integrated within itself, and it is such a simple tool to use.

  • 136.
    Anders, Söderholm
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Justus, Sörman
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    GPU-accelleration of image rendering and sorting algorithms with the OpenCL framework2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Today's computer systems often contains several different processing units aside from the CPU. Among these the GPU is a very common processing unit with an immense compute power that is available in almost all computer systems. How do we make use of this processing power that lies within our machines? One answer is the OpenCL framework that is designed for just this, to open up the possibilities of using all the different types of processing units in a computer system. This thesis will discuss the advantages and disadvantages of using the integrated GPU available in a basic workstation computer for computation of image processing and sorting algorithms. These tasks are computationally intensive and the authors will analyze if an integrated GPU is up to the task of accelerating the processing of these algorithms. The OpenCL framework makes it possible to run one implementation on different processing units, to provide perspective we will benchmark our implementations on both the GPU and the CPU and compare the results. A heterogeneous approach that combines the two above mentioned processing units will also be tested and discussed. The OpenCL framework is analyzed from a development perspective and what advantages and disadvantages it brings to the development process will be presented.

  • 137.
    Anderson, Collin
    et al.
    University of Pennsylvania, USA.
    Winter, Philipp
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    -, Roya
    Global Network Interference Detection over the RIPE Atlas Network2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Existing censorship measurement platforms frequentlysuffer from poor adoption, insufficient geographic coverage, and scalability problems. In order to outline ananalytical framework and data collection needs for futureubiquitous measurements initiatives, we build on top ofthe existent and widely-deployed RIPE Atlas platform.In particular, we propose methods for monitoring thereachability of vital services through an algorithm thatbalances timeliness, diversity, and cost. We then use Atlas to investigate blocking events in Turkey and Russia.Our measurements identify under-examined forms of interference and provide evidence of cooperation betweena well-known blogging platform and government authorities for purposes of blocking hosted content.

  • 138.
    Andersson, Anders
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten. Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Extensions for Distributed Moving Base Driving Simulators2017Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Modern vehicles are complex systems. Different design stages for such a complex system include evaluation using models and submodels, hardware-in-the-loop systems and complete vehicles. Once a vehicle is delivered to the market evaluation continues by the public. One kind of tool that can be used during many stages of a vehicle lifecycle is driving simulators.

    The use of driving simulators with a human driver is commonly focused on driver behavior. In a high fidelity moving base driving simulator it is possible to provide realistic and repetitive driving situations using distinctive features such as: physical modelling of driven vehicle, a moving base, a physical cabin interface and an audio and visual representation of the driving environment. A desired but difficult goal to achieve using a moving base driving simulator is to have behavioral validity. In other words, \A driver in a moving base driving simulator should have the same driving behavior as he or she would have during the same driving task in a real vehicle.".

    In this thesis the focus is on high fidelity moving base driving simulators. The main target is to improve the behavior validity or to maintain behavior validity while adding complexity to the simulator. One main assumption in this thesis is that systems closer to the final product provide better accuracy and are perceived better if properly integrated. Thus, the approach in this thesis is to try to ease incorporation of such systems using combinations of the methods hardware-in-the-loop and distributed simulation. Hardware-in-the-loop is a method where hardware is interfaced into a software controlled environment/simulation. Distributed simulation is a method where parts of a simulation at physically different locations are connected together. For some simulator laboratories distributed simulation is the only feasible option since some hardware cannot be moved in an easy way.

    Results presented in this thesis show that a complete vehicle or hardware-in-the-loop test laboratory can successfully be connected to a moving base driving simulator. Further, it is demonstrated that using a framework for distributed simulation eases communication and integration due to standardized interfaces. One identified potential problem is complexity in interface wrappers when integrating hardware-in-the-loop in a distributed simulation framework. From this aspect, it is important to consider the model design and the intersections between software and hardware models. Another important issue discussed is the increased delay in overhead time when using a framework for distributed simulation.

  • 139.
    Andersson, Anders
    et al.
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Fordonsteknik och simulering, FTS.
    Andersson Hultgren, Jonas
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Fordonsteknik och simulering, FTS.
    Leandertz, Rickard
    HiQ.
    Johansson, Martin
    Pitch Technologies.
    Eriksson, Steve
    Pitch Technologies.
    Jakobson, Ola
    Volvo Car Corporation.
    A Driving Simulation Platform using Distributed Vehicle Simulators and HLA2015Ingår i: Proceedings of the DSC 2015 Europe: Driving Simulation Conference & Exhibition, 2015, 123-130 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modern vehicles are complex systems consisting of an increasing large multitude of components that operate together. While functional verification on individual components is important, it is also important to test components within a driving environment, both from a functional perspective and from a driver perspective. One proven way for testing is vehicle simulators and in this work the main goals have been to increase flexibility and scalability by introducing a distributed driving simulator platform.

    As an example, consider a workflow where a developer can go from a desktop simulation to an intermediate driving simulator to a high fidelity driving simulator with Hardware-In-the-Loop systems close to a finished vehicle in an easy way. To accomplish this, a distributed simulation architecture was designed and implemented that divides a driving simulator environment into four major entities with well-defined interfaces, using HLA as the method of communication. This platform was evaluated on two aspects, flexibility/scalability and timing performance. Results show that increased flexibility and scalability was achieved when using a distributed simulation platform. It is also shown that latency was only slightly increased when using HLA.

  • 140.
    Andersson, Anders
    et al.
    Statens väg- och transportforskningsinstitut, Fordonsteknik och simulering, FTS.
    Andersson Hultgren, Jonas
    Statens väg- och transportforskningsinstitut, Fordonsteknik och simulering, FTS.
    Leandertz, Rickard
    Hiq Accelerated Concept Evaluation AB, Stockholm, Sweden.
    Johansson, Martin
    Pitch Technologies.
    Eriksson, Steve
    Pitch Technologies.
    Jakobson, Ola
    Volvo Car Corporation.
    A Driving Simulation Platform using Distributed Vehicle Simulators and HLA2015Ingår i: Proceedings of the DSC 2015 Europe: Driving Simulation Conference & Exhibition / [ed] Heinrich Bülthoff, Andras Kemeny and Paolo Pretto, 2015, 123-130 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modern vehicles are complex systems consisting of an increasing large multitude of components that operate together. While functional verification on individual components is important, it is also important to test components within a driving environment, both from a functional perspective and from a driver perspective. One proven way for testing is vehicle simulators and in this work the main goals have been to increase flexibility and scalability by introducing a distributed driving simulator platform.

    As an example, consider a workflow where a developer can go from a desktop simulation to an intermediate driving simulator to a high fidelity driving simulator with Hardware-In-the-Loop systems close to a finished vehicle in an easy way. To accomplish this, a distributed simulation architecture was designed and implemented that divides a driving simulator environment into four major entities with well-defined interfaces, using HLA as the method of communication. This platform was evaluated on two aspects, flexibility/scalability and timing performance. Results show that increased flexibility and scalability was achieved when using a distributed simulation platform. It is also shown that latency was only slightly increased when using HLA.

  • 141.
    Andersson, Anders
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Swedish National Road and Transportation Research Institute.
    Fritzson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Models for Distributed Real-Time Simulation in a Vehicle Co-Simulator Setup2013Ingår i: Proceedings of the 5th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools; April 19, University of Nottingham, Nottingham, UK / [ed] Henrik Nilsson, Linköping: Linköping University Electronic Press, 2013, Vol. 84, 131-139 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    A car model in Modelica has been developed to be used in a new setup for distributed real-time simulation where a moving base car simulator is connected with a real car in a chassis dynamometer via a 500m fiber optic communication link. The new co-simulator set-up can be used in a number of configurations where hardware in the loop can be interchanged with software in the loop. The models presented in this paper are the basic blocks chosen for modeling the system in the context of a distributed real-time simulation; estimating parameters for the powertrain model; the choice of numeric solver; and the interaction with the solver for real-time properties.

  • 142.
    Andersson, Birger
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Data- och systemvetenskap, DSV.
    Bergholtz, Maria
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Data- och systemvetenskap, DSV.
    Edirisuriya, A.
    Ilayperuma, T.
    Jayaweera, P.
    Johannesson, Paul
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Data- och systemvetenskap, DSV.
    Zdravkovic, Jelena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Data- och systemvetenskap, DSV.
    Enterprise sustainability through the alignment of goal models and business models2008Ingår i: CEUR Workshop Proc., 2008, 73-87 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Business modelling can be used as a starting point for business analysis. The core of a business model is information about resources, events, agents, and their relations. The motivation of a business model can be found in the goals of an enterprise and those are made explicit in a goal model. This paper discusses the alignment of business models with goal models and proposes a method for constructing business models based on goal models. The method assists in the design of business models that conform to the explicit goals of an enterprise. Main benefits are clear and uniform goal formulations, well founded business model designs, and increased traceability between models.

  • 143.
    Andersson, Dan
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Implementation av prototyp för inomhuspositionering2013Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Utveckling av teknik skapar ständigt nya möjligheter men innebär också stora förändringar för företag och organisationer. Mobiltelefoner, surfplattor, bärbara datorer, mobilkommunikation och molnteknik gör det möjligt idag att inte längre vara bunden av tid, plats eller en enhet för att kunna arbeta. Förändringen innebär att en ny typ av flexibla och yteffektiva kontor med inga fasta arbetsplatser blir allt vanligare. Problemet med de så kallade flexkontoren är att veta var eller när en kollega befinner sig på kontoret är inte lika självklart, framförallt om det är stort kontor med flera våningsplan.

    Målsättningen med detta arbete är att ta fram och implementera en inomhuspositioneringstjänst eller en så kallad Location-Based Service, till företaget Connecta AB. Tjänsten ska göra det möjligt för användare att med hjälp av sin mobiltelefon dela med sig av sin nuvarande arbetsplats i en kontorsmiljö.

    Resultatet av arbetet är en Location Based Service som gör det möjligt för en användare att med hjälp av en Androidtelefon med stöd för kortdistanskommunikationstekniken Near Field Communcication att dela med sig av sin nuvarande arbetsplats. Den molnbaserade serverlösningen Windows Azure används för att lagra registrerade arbetsplatser.

  • 144.
    Andersson, Daniel
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Integrated Test Environment2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    To implement a command line interpreter is normally an easy task. The task getsharder when adding requirements of multi instance functions and the system is torun on a multi-processor security critical embedded system. This thesis describesa first iteration of the system development. The project behind the thesis consistsof requirement elicitation, design, implementation and unit testing. The resultfrom the project is a working first version of the system.

  • 145.
    Andersson, Erik Olov Mårten
    Linköpings universitet, Institutionen för datavetenskap.
    A Gameful Quest to Make Second Language Acquisition Fun2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This study explores the application of principles from game design, and the motivational psychology it is founded upon, to the domain of second language acquisition. A gameful design process based on playtesting andanalysis with design lenses is adapted and used to iteratively design and develop a system for conversation practice with the goal of creating a motivating and engaging experience.The results indicate effectiveness of the process, but generalizing the results would require further research with bigger sample sizes and studies with varied core activities.

  • 146.
    Andersson, Filip
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Fault Diagnosis in Distributed Simulation Systems over Wide Area Networks using Active Probing2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The domain of distributed simulation is growing rapidly. This growth leads to larger and more complex supporting network architectures with high requirements on availability and reliability. For this purpose, efficient fault-monitoring is required. This work is an attempt to evaluate the viability of an Active probing approach in a distributed simulation system in a wide area network setting. In addition, some effort was directed towards building the probing-software with future extensions in mind. The Active probing approach was implemented and tested against certain performance requirements in a simulated environment. It was concluded that the approach is viable for detecting the health of the network components. However, additional research is required to draw a conclusion about the viability in more complicated scenarios that depend on more than the responsiveness of the nodes. The extensibility of the implemented software was evaluated with the QMOOD-metric and not deemed particularly extensible.

  • 147.
    Andersson, Fredrik
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Storing and structuring big data with businessintelligence in mind2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Sectra has a customer database with approximately 1600 customers across the world. In this system there exists not only medical information but alsoinformation about the environment which the system runs in, usage  pattern and much more.

    This report is about storing data received from log les into a suitable database. Sectra wants to be able to analyze this information so that they can make strategic decisions and get a better understanding of their customers' needs. The tested databases are MongoDB, Cassandra, and MySQL. The results shows that MySQL  is not suitable for storing large amount of data with the current conguration. On the other hand, both MongoDB and Cassandra performed well with the growing amount of data.

  • 148.
    Andersson, Fredrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Utveckling av GIS-applikation för effektivisering av planeringsarbeten för infrastruktur2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Planeringsarbeten för infrastruktur sker ofta med hjälp av speciella programvaror som CAD för att skapa ritningar på kartor över områden där tänkta infrastrukturer skall utvecklas. Som en effektivisering för dessa arbeten handlar denna studie om implementering av en GIS-applikation för att motivera fördelar med GIS och sättet för hantering samt visualisering av geografisk information. En webbapplikation som hanterar baskartor samt överliggande vektorlager för infrastruktur utvecklas, samt även att samma kartdata över infrastrukturen kopplas till en mobilapplikation för att effektivisera eventuella inventeringsarbeten av infrastrukur med hjälp av GPS för att kunna positionera infrastruktur på ett bra sätt. Tekniken bakom utvecklingen bygger på HTML, CSS och JavaScript samt molntjänstlagrin av infrastruktursdata i en geodatabas . GIS-applikationen sammanställer svar på frågor som bevisar hur GIS på ett tillfredställande sätt mycket väl skulle kunna implementeras och användas praktiskt i ett utvecklingsarbete för infrastruktur i dagens morderna samhälle. 

  • 149.
    Andersson, Gustaf
    Karlstads universitet, Fakulteten för humaniora och samhällsvetenskap (from 2013), Handelshögskolan.
    En Kvalitativ studie om förändringsarbete vid ett IT-projekt: En fallstudie på en segelflygklubb2015Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Organisationer och ledare saknar ofta en förståelse om kärnan i ett förändringsarbete, förståelsen om hur människor fungerar. Förändring leder ofta till starka känslor och vissa drabbas hårdare än andra, medarbetare kan lätt omvandlas till motståndare om ledningen inte möter personalen rätt.

     

    Syftet med denna uppsats är att ge en kunskapsbas i hur en projektgrupp ska arbeta mot användare för att motivera dem till en positiv inställning inför förändringen. Den ger en förståelse för människors behov, drivkrafter och olika orsaker till varför motstånd till förändring kan uppstå hos de berörda.

    Datainsamlingen har skett genom en litteraturstudie inom området för att sedan samla in empiri genom halvstrukturerade intervjuer. Samtliga respondenter kommer från en segelflygsförening och syftet med det var att ta reda på hur föreningen hanterat olika förändringsarbeten. Dels ett redan avslutat förändringsarbete då de övergick till ett system för internetbokning av flygplan och även ett förändringsarbete som inte realiserats än, en digital lösning till deras tidsrapportering.

     

    Det finns flera olika alternativ som en ledare kan applicera för att motivera sina anställda vid ett förändringsarbete. Dessa tillvägagångssätt kan vara effektiva på sina egna vis, mycket beroende på sammanhanget och det specifika fallet. För att effektivisera momentet motivation gäller det att välja rätt tillvägagångssätt vid rätt tillfälle. Något som förutsätter att ledare har en förståelse för individen och de reaktioner denne har gentemot förändringen.

  • 150.
    Andersson, Gustav
    Linköpings universitet, Institutionen för datavetenskap, Interaktiva och kognitiva system. Linköpings universitet, Tekniska högskolan.
    Implementing touch interaction in a casual mobile game2014Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis is to help developers in the touch design of casual games. The thesis work was made on the development platform Gideros Mobile and much of the thesis theory and methods will be based on that work. The purpose of the report is to show what one should think about when making a casual game in a touch design perspective, like taking into account that most people are used to one type of input design (like swiping or tapping), that you should design the game with the purpose to reach out to as a large audience as possible (taking into account people with disabilities) and some small notes on what should be avoided so not to deter people from wanting to play the game. It is important to note that this thesis is built for the purpose of mobile casual games, others will probably not find this thesis relevant.

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