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  • 51.
    Andersson, Simon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Influence of File Systems on Performance When Working with an Abundance of Small Files2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    High-performance computing is widely used within the scientific community to perform demanding computational work. Using the resources available at a high-performance center in an efficient manner is of great importance. One potential bottleneck for high-performance computing is file systems.

    In this study two different file systems, the Lustre file system and MATLAB Datastore, have been evaluated in terms of performance when performing computations on an abundance of small files. The performance test consisted of classification of large numbers of small (<2 megabytes) images in MATLAB using the high-performance computer system Kebnekaise at HPC2N in Umeå.

    Results indicate that MATLAB Datastore gives better performance than the Lustre file system for all images sets tested in the study. This makes it possible to recommend using MATLAB Datastore over the Lustre file system in situations where large number of smaller files are to be read and from the file system.

  • 52.
    Andersson Thunberg, Karl
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Large Scale Server Publishing for Dynamic Content2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The number of interactive and dynamic web services on the Internet is growing more and more and to accommodate as much functionality as possible, many techniques for asynchronous web communication are being developed. This thesis report describes the evaluation of an existing web service that uses bidirectional communication over the web to provide voting functionality in real-time on web pages. The thesis consists of an assessment of problem domains, an evaluation of the system and an implementation of some of the identified problems. It focuses on a few core issues of the current solution, namely the communication techniques between the client and the server, the setup of the overarching structure of the system and the separation of messaging channels for different use cases.The evaluation of the reference system was motivated by addressing the issue of being able to packet the service better as a product and create a distinction between the use case and the underlying system. It was done so that the stakeholders of the product may more easily define the way the service can be used and so that a better course of action can be taken for continuing the development of the service. The implemented solution shows an example of how the messaging channels could be separated and what kind of trade-os exist between the current and implemented solution.

  • 53.
    André, Caroline
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Design aspects in a mobile biofeedback system - developmentof a new interface concept usingdesign qualities2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    It has been established that long term stress can lead to chronic illness of cardiac disease and vascular disorder. In the way people live their lives today they are surrounded by stress and they contribute to the stressful society when they constantly chase the time. The Mobile Life Centre explores how the system Aective Health can get people to reect up on their stress levels and connect that to their everyday activities by using bio sensors and a mobile phone. The bio sensor data visualization in the interface of the system is today tied to time. Since time is perceived dierently from person to person that is something that has caused problems for the design team of Aective Health. This thesis examines how dierent representations of time in user interfaces can be used to mediate the design qualities of subjective time, aliveness and uency in the Aective Health system. As a result from investigating the time aspect and how time can be visualized in a subjective way a suggestion for a design solution was developed.

  • 54.
    Anjomshoae, Sule
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå University.
    Främling, Kary
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå University.
    Najjar, Amro
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå University.
    Explanations of black-box model predictions by contextual importance and utility2019Ingår i: Explainable, transparent autonomous agents and multi-agent systems: first international workshop, EXTRAAMAS 2019, Montreal, QC, Canada, May 13–14, 2019, revised selected papers / [ed] Davide Calvaresi, Amro Najjar, Michael Schumacher, Kary Främling, Springer, 2019, s. 95-109Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The significant advances in autonomous systems together with an immensely wider application domain have increased the need for trustable intelligent systems. Explainable artificial intelligence is gaining considerable attention among researchers and developers to address this requirement. Although there is an increasing number of works on interpretable and trans- parent machine learning algorithms, they are mostly intended for the technical users. Explanations for the end-user have been neglected in many usable and practical applications. In this work, we present the Contextual Importance (CI) and Contextual Utility (CU) concepts to extract explanations that are easily understandable by experts as well as novice users. This method explains the prediction results without transforming the model into an interpretable one. We present an example of providing explanations for linear and non-linear models to demonstrate the generalizability of the method. CI and CU are numerical values that can be represented to the user in visuals and natural language form to justify actions and explain reasoning for individual instances, situations, and contexts. We show the utility of explanations in car selection example and Iris flower classification by presenting complete (i.e. the causes of an individual prediction) and contrastive explanation (i.e. contrasting instance against the instance of interest). The experimental results show the feasibility and validity of the provided explanation methods.

  • 55.
    Anjomshoae, Sule
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Najjar, Amro
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Calvaresi, Davide
    Främling, Kary
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Explainable Agents and Robots: Results from a Systematic Literature Review2019Ingår i: AAMAS '19: Proceedings of the 18th International Conference on Autonomous Agents and MultiAgent Systems / [ed] N. Agmon, M. E. Taylor, E. Elkind, M. Veloso, International Foundation for Autonomous Agents and MultiAgent Systems , 2019, s. 1078-1088Konferensbidrag (Refereegranskat)
    Abstract [en]

    Humans are increasingly relying on complex systems that heavily adopts Artificial Intelligence (AI) techniques. Such systems are employed in a growing number of domains, and making them explainable is an impelling priority. Recently, the domain of eXplainable Artificial Intelligence (XAI) emerged with the aims of fostering transparency and trustworthiness. Several reviews have been conducted. Nevertheless, most of them deal with data-driven XAI to overcome the opaqueness of black-box algorithms. Contributions addressing goal-driven XAI (e.g., explainable agency for robots and agents) are still missing. This paper aims at filling this gap, proposing a Systematic Literature Review. The main findings are (i) a considerable portion of the papers propose conceptual studies, or lack evaluations or tackle relatively simple scenarios; (ii) almost all of the studied papers deal with robots/agents explaining their behaviors to the human users, and very few works addressed inter-robot (inter-agent) explainability. Finally, (iii) while providing explanations to non-expert users has been outlined as a necessity, only a few works addressed the issues of personalization and context-awareness

  • 56.
    Anjum, Chaudhary
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Learner’s Interaction With Information and Communication Technologies2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This Master’s thesis aims to explore how children and teen-agers (i.e. learners) interact and create a use for information and communication technology in the classroom during their lectures. The study is based on distributed cognition theory in order to describe a cognitive  system which involves interactions among humans (i.e. learners), artifacts which they use (i.e. information and communication technology active boards) and the environment in which they interact (i.e. a classroom).

    User’s (such as the children, teen-agers and teachers) interaction with information and communication technology can lead towards new and important ways of invention in the classroom. No doubt the ideas, thoughts and vision of these users (such as children and teenagers) are very important which can change an environment that supports learning. The Distributed Cognition Approach is a widely acknowledged approach, but it is less commonly applied in order to observe learner’s (such as children and teen-agers) interaction with information and communication technologies in their learning setting. Therefore this study aims to explore the children and teen-agers interaction with the information and communication technology active boards by using distributed cognition theory which can be expressed as important and interesting for the researchers, designers and developers in evaluating, designing and developing effective interactive technologies that supports better education.

    Through an empirical case study, qualitative data have been collected using interviews and observations. Based on related research, related theory, qualitative results and analysis, a conclusion is presented which shows that (with the help of the analysis of distributed cognition theory) the information and communication technology active boards seems to engage the children and teen-ager’s to collaborative learning activities which supports collaboration and shared knowledge. It helps to capture their concentration towards learning which can increase the opportunities and possibilities of better learning results related to their education.

    The distributed cognition approach provides an analytic and investigative methodology in order to examine the learner’s interactions with artifacts which are difficult with other traditional methodologies to the analysis of cognitive-tasks. This approach highlights the complicated interdependencies among learners and artifacts in collaborative learning activities.

  • 57.
    Ansari, Hamon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Performance Comparison of Two Database Management Systems MySQL vs MongoDB2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Databases are commonly used today in a vast amounts of applications. The main point in using databases is to be able to store and access data fast and in a secure way. These databases need to be able make different operations as fast as possible without losing data. The two main database technologies used today are NoSQL and SQL (StructuredQuery Language) databases. NoSQL is an umbrella term for all DBMS (Database Management system) which are not using SQL like relational databases do. NoSQL stands for non-SQL, non-relational or not only SQL.

    In this thesis one DBMS from each database technology is compared to each other. The comparison is based on space allocation when they contain different amounts of records and time performance when executing different operations on different amounts of records. The operation stested for the speed performance were insertion, select, update and remove.

    The results showed that MySQL allocated less space when containing large amounts of records. While MongoDB was faster in almost all test case for every operation.

  • 58.
    Anttila, L.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Eklund, Patrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kallin, Lena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Koskinen, P.
    Penttilä, T.-A.
    The Generalised Preprocessing Perceptron for Medical Data Analysis: A Case Study for the Polycystic Ovary Syndrome1996Ingår i: Cybernetics and Systems '96: Proceedings of the 13th European Meeting on Cybernetics and Systems Research / [ed] Robert Trappl, 1996, s. 597-602Konferensbidrag (Övrigt vetenskapligt)
  • 59. Arafat, Yeasin
    et al.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Rashid, Jayedur
    Parameterized sensor model and an approach for measuring goodness of robotic maps2010Ingår i: Proceedings of the 15th IASTED International Conference on Robotics and Applications (RA 2010), ACTA Press, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Map building is a classical problem in mobile and au tonomous robotics, and sensor models is a way to interpret raw sensory information, especially for building maps. In this paper we propose a parameterized sensor model, and optimize map goodness with respect to these parameters. A new approach, measuring the goodness of maps without a handcrafted map of the actual environment is introduced and evaluated. Three different techniques; statistical anal ysis, derivative of images, and comparison of binary maps have been used as estimates of map goodness. The results show that the proposed sensor model generates better maps than a standard sensor model. However, the proposed ap proach of measuring goodness of maps does not improve the results as much as expected.

  • 60.
    Armgren, Marc
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Mobile Cross-platform development versus native development A look at Xamarin Platform2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The world of mobile phones is currently inhabited by three large rivals. We have Apple with their iOS devices, Microsoft with the Windows Phone line, and various devices with Googles Android operating system. Developing for all platforms individually is labour intensive and time consuming. Therefore cross-platform development is of interest for companies large as small. The technique which gives performance closest to native development is called cross compiling, which compiles native applications from a common codebase. This thesis takes a closer look at the performance of the tool Xamarin Platform, in which applications for iOS, Windows Phone and Android can be created. The performance of Xamarin Platform applications on iOS and Android is native for most user interface components. Network performance is native or better. However computational tasks are very slow compared to natively developed applications. Xamarin PlatformWindows Phone applications are not covered by this thesis.

  • 61.
    Armstrong, Django
    et al.
    School of Computing, University of Leeds.
    Djemame, Karin
    School of Computing, University of Leeds.
    Nair, Srijith
    British Telecom.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Ziegler, Wolfgang
    Fraunhofer SCAI.
    Towards a Contextualization Solution for Cloud Platform Services2011Ingår i: 2011 IEEE Third International Conference on Cloud Computing Technology and Science, IEEE Computer Society, 2011, s. 328-331Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose a cloud contextualization mechanism which operates in two stages, contextualization of VM images prior to service deployment (PaaS level) and self-contextualization of VM instances created from the image (IaaS level). The contextualization tools are implemented as part of the OPTIMIS Toolkit, a set of software components for simplified management of cloud services and infrastructures. We present the architecture of our contextualization tools and the feasibility of our contextualization mechanism is demonstrated in a three-tier web application scenario. Preliminary performance results suggest acceptable performance and scalability.

  • 62.
    Armstrong, Django
    et al.
    University of Leeds.
    Espling, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Djemame, Karim
    University of Leeds.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Contextualization: dynamic configuration of virtual machines2015Ingår i: Journal of Cloud Computing - Advances, Systems and Applications, ISSN 2192-113X, Vol. 4, nr 17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New VM instances are created from static templates that contain the basic configuration of the VM to achieve elasticity with regards to capacity. Instance specific settings can be injected into the VM during the deployment phase through means of contextualization. So far this is limited to a single data source and data remains static throughout the lifecycle of the VM.

    We present a layered approach to contextualization that supports different classes of contextualization data available from several sources. The settings are made available to the VM through virtual devices. Inside each VM data from different classes are layered on top of each other to create a unified file hierarchy.

    Context data can be modified during runtime by updating the contents of the virtual devices, making our approach the first contextualization approach to natively support recontextualization. Recontextualization enables runtime reconfiguration of an executing service and can act as a trigger and key enabler of self-* techniques. This trigger provides a service with a mechanism to adapt or optimize itself in response to a changing environment. The runtime reconfiguration using recontextualization and its potential gains are illustrated in an example with a distributed file system, demonstrating the feasibility of our approach.

  • 63.
    Armstrong, Django
    et al.
    University of Leeds.
    Espling, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Djemame, Karim
    University of Leeds.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Runtime virtual machine recontextualization for clouds2013Ingår i: Euro-Par 2012: Parallel Processing Workshops / [ed] Ioannis Caragiannis et al., Springer Berlin/Heidelberg, 2013, Vol. 7640, s. 567-576Konferensbidrag (Refereegranskat)
    Abstract [en]

    We introduce and define the concept of recontextualization for cloud applications by extending contextualization, i.e. the dynamic configuration of virtual machines (VM) upon initialization, with autonomous updates during runtime. Recontextualization allows VM images and instances to be dynamically re-configured without restarts or downtime, and the concept is applicable to all aspects of configuring a VM from virtual hardware to multi-tier software stacks. Moreover, we propose a runtime cloud recontextualization mechanism based on virtual device management that enables recontextualization without the need to customize the guest VM. We illustrate our concept and validate our mechanism via a use case demonstration: the reconfiguration of a cross-cloud migratable monitoring service in a dynamic cloud environment. We discuss the details of the interoperable recontextualization mechanism, its architecture and demonstrate a proof of concept implementation. A performance evaluation illustrates the feasibility of the approach and shows that the recontextualization mechanism performs adequately with an overhead of 18% of the total migration time.

  • 64.
    Arvidsson, Andreas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bygdemark, Jörgen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    JÄMFÖRELSE MELLAN ORACLE RDBMS, ORACLE NOSQL OCH MONGODB2019Självständigt arbete på grundnivå (konstnärlig kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Databases are present everywhere in our modern society and the amount of data that have to be stored is constantly increasing, which means that it’s now more important than ever to be able to handle massive data sets e‚ffectively. NoSQL databases2 were developed to solve this problem by efficiently storing large amounts of data and enable fast access to that data. Since NoSQL databases only became popular within the last ten years, they haven’t been as well researched as relational databases. An in-depth evaluation is carried out on six distinct features, where one part is comparative performance tests. Th‘e other features are: scalability, consistency, availability, durability and reliability. MongoDB and Oracle NoSQL are the NoSQL databases used and together with Oracle RDBMS as relational database make up the basis for a comparative study of the above mentioned features.Th‘e results showed that there are big diff‚erences between how data is handled in NoSQL compared to relational databases that will aff‚ect the choice of database, e.g. that NoSQL tends to prioritize that clients can reach the database over non-contradictory data and lowering the demands on transaction management to increase performance and storage capacity. Furthermore, the performance tests showed that both NoSQL databases performed be‹er than the relational database regardless of the data set size. MongoDB was clearly the fastest on reading operations, while Oracle NoSQL performed write operations the fastest most of the time. Both NoSQL databases are impacted less by a growing data set than the relational database for both read and write operations.

  • 65. Asan, Noor Badariah
    et al.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Perez, Mauricio David
    Shah, Syaiful Redzwan Mohd
    Velander, Jacob
    Blokhuis, Taco J.
    Voigt, Thiemo
    Augustine, Robin
    Assessment of Blood Vessel Effect on Fat-Intrabody Communication Using Numerical and Ex-Vivo Models at 2.45 GHZ2019Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 89886-89900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential offered by the intra-body communication (IBC) over the past few years has resulted in a spike of interest for the topic, specifically for medical applications. Fat-IBC is subsequently a novel alternative technique that utilizes fat tissue as a communication channel. This work aimed to identify such transmission medium and its performance in varying blood-vessel systems at 2.45 GHz, particularly in the context of the IBC and medical applications. It incorporated three-dimensional (3D) electromagnetic simulations and laboratory investigations that implemented models of blood vessels of varying orientations, sizes, and positions. Such investigations were undertaken by using ex-vivo porcine tissues and three blood-vessel system configurations. These configurations represent extreme cases of real-life scenarios that sufficiently elucidated their principal influence on the transmission. The blood-vessel models consisted of ex-vivo muscle tissues and copper rods. The results showed that the blood vessels crossing the channel vertically contributed to 5.1 dB and 17.1 dB signal losses for muscle and copper rods, respectively, which is the worst-case scenario in the context of fat-channel with perturbance. In contrast, blood vessels aligned-longitudinally in the channel have less effect and yielded 4.5 dB and 4.2 dB signal losses for muscle and copper rods, respectively. Meanwhile, the blood vessels crossing the channel horizontally displayed 3.4 dB and 1.9 dB signal losses for muscle and copper rods, respectively, which were the smallest losses among the configurations. The laboratory investigations were in agreement with the simulations. Thus, this work substantiated the fat-IBC signal transmission variability in the context of varying blood vessel configurations.

  • 66. Asan, Noor Badariah
    et al.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Shah, Syaiful Redzwan Mohd
    Rydberg, Anders
    Blokhuis, Taco J.
    Carlsson, Per-Ola
    Voigt, Thiemo
    Augustine, Robin
    Intra-body microwave communication through adipose tissue2017Ingår i: Healthcare technology letters, E-ISSN 2053-3713, Vol. 4, nr 4, s. 115-121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The human body can act as a medium for the transmission of electromagnetic waves in the wireless body sensor networks context. However, there are transmission losses in biological tissues due to the presence of water and salts. This Letter focuses on lateral intra-body microwave communication through different biological tissue layers and demonstrates the effect of the tissue thicknesses by comparing signal coupling in the channel. For this work, the authors utilise the R-band frequencies since it overlaps the industrial, scientific and medical radio (ISM) band. The channel model in human tissues is proposed based on electromagnetic simulations, validated using equivalent phantom and ex-vivo measurements. The phantom and ex-vivo measurements are compared with simulation modelling. The results show that electromagnetic communication is feasible in the adipose tissue layer with a low attenuation of approximate to 2 dB per 20 mm for phantom measurements and 4 dB per 20 mm for ex-vivo measurements at 2 GHz. Since the dielectric losses of human adipose tissues are almost half of ex-vivo tissue, an attenuation of around 3 dB per 20 mm is expected. The results show that human adipose tissue can be used as an intra-body communication channel.

  • 67. Asan, Noor Badariah
    et al.
    Redzwan, Syaiful
    Rydberg, Anders
    Augustine, Robin
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Voigt, Thiemo
    Human Fat Tissue: A Microwave Communication Channel2017Ingår i: 2017 First IEEE MTT-S International Microwave Bio Conference (IMBIOC), IEEE, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present an approach for communication through human body tissue in the R-band frequency range. This study examines the ranges of microwave frequencies suitable for intra-body communication. The human body tissues are characterized with respect to their transmission properties using simulation modeling and phantom measurements. The variations in signal coupling with respect to different tissue thicknesses are studied. The simulation and phantom measurement results show that electromagnetic communication in the fat layer is viable with attenuation of approximately 2 dB per 20 mm.

  • 68. Asan, Noor Badariah
    et al.
    Velander, Jacob
    Redzwan, Syaiful
    Augustine, Robin
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Voigt, Thiemo
    Blokhuis, Taco J.
    Reliability of the Fat Tissue Channel for Intra-body Microwave Communication2017Ingår i: 2017 IEEE Conference on Antenna Measurements & Applications (CAMA), IEEE , 2017, s. 310-313Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recently, the human fat tissue has been proposed as a microwave channel for intra-body sensor applications. In this work, we assess how disturbances can prevent reliable microwave propagation through the fat channel. Perturbants of different sizes are considered. The simulation and experimental results show that efficient communication through the fat channel is possible even in the presence of perturbants such as embedded muscle layers and blood vessels. We show that the communication channel is not affected by perturbants that are smaller than 15 mm cube.

  • 69. Asan, Noor Badariah
    et al.
    Velander, Jacob
    Redzwan, Syaiful
    Perez, Mauricio D.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Blokhuis, Taco J.
    Voigt, Thiemo
    Augustine, Robin
    Effect of Thickness Inhomogeneity in Fat Tissue on In-Body Microwave Propagation2018Ingår i: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBIOC), IEEE, 2018, s. 136-138Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent studies, it has been found that fat tissue can be used as a microwave communication channel. In this article, the effect of thickness inhomogeneities in fat tissues on the performance of in-body microwave communication at 2.45 GHz is investigated using phantom models. We considered two models namely concave and convex geometrical fat distribution to account for the thickness inhomogeneities. The thickness of the fat tissue is varied from 5 mm to 45 mm and the Gap between the transmitter/receiver and the starting and ending of concavity/convexity is varied from 0 mm to 25 mm for a length of 100 mm to study the behavior in the microwave propagation. The phantoms of different geometries, concave and convex, are used in this work to validate the numerical studies. It was noticed that the convex model exhibited higher signal coupling by an amount of 1 dB (simulation) and 2 dB (measurement) compared to the concave model. From the study, it was observed that the signal transmission improves up to 30 mm thick fat and reaches a plateau when the thickness is increased further.

  • 70.
    Asseffa, Samrawit
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Seleshi, Bihil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    A Case Study on Differential Privacy2017Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Throughout the ages, human beings prefer to keep most things secret and brand this overall state with the title of privacy. Like most significant terms, privacy tends to create controversy regarding the extent of its flexible boundaries, since various technological advancements are slowly leaching away the power people have over their own information. Even as cell phone brands release new upgrades, the ways in which information is communicated has drastically increased, in turn facilitating the techniques in which people’s privacy can be tampered with. Therefore, questioning the methodology by which people can maintain their privacy in the twenty-first century is a validated action undoubtedly conducted by the multitude of the world’s population.

    Admittedly, data is everywhere. The world has become an explosion of information, and it should not come as a surprise, especially in a time when data storage is cheap and accessible. Various institutions use this data to conduct research, track the behavior of users, recommend products or maintain national security. As a result, corporations’ need for information is growing by the minute. Companies need to know as much as possible about their customers. Nonetheless, how can this be achieved without compromising the privacy of individuals? How can companies provide great features and maintain great privacy?

    These questions can be answered by a current, anticipated research topic in the field of data privacy: differential privacy. Differential privacy is a branch of statistics that aims to attain the widest range of data while achieving a robust, significant and mathematically accurate definition of privacy.

    Thus, the objective of this thesis will be describing and analyzing the concept of differential privacy and its properties that lead to the betterment of data privacy. Hence, we will try to study the basic state-of-the-art methods, the model and the challenges of differential privacy.

    After analyzing the state-of-the-art differential privacy methods, this thesis will focus on an actual case study that is concerned with two types of different datasets which are experimented with one of the methods of differential privacy methods. We design a basic framework that tries to achieves differential privacy guarantee and evaluate the results regarding the level of privacy achieved.

  • 71.
    Astahovs, Ilja
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Travel time estimation based on previous experience - Pre-study and prototyping2015Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Travel time depends on various factors, which can be described by data coming from sensors. The author makes an assumption that for the same trip conditions travel time will be the same, and if we can collect enough information on the current trip conditions and find a matching trip which took place in the past, we can estimate the travel time for future trips. The project aim is to design and prototype a system capable of collecting this data, organizing, storing and using it to find matching trips, with the real-time performance being the main consideration. The scope of the system is limited by the needs of a logistic company which wants to be able to track its vehicles and estimate their travel times.

    The resulting system is tested in various settings to find out how well it performs. The author identifies the settings which are suitable for the particular implementation and suggests further improvements which are meant to extend the settings.

  • 72.
    Astahovs, Ilja
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Use of design patterns for mobile game development2012Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Design patterns have been a valuable asset to software developers for a long time. All kind of software, including games, benefit from re-using the well known solutions to the common problems. Building a game from scratch requires a carefully made design and this is where design patterns come handy. However, the approach to game development has changed lately. The importance to learn the design patterns has been de-emphasized as frameworks and complete game engines emerge. Many design approaches provided by them are used out the box, often taken as some kind of standard.

    The purpose of this paper is to show how some of the classical design patterns can be used in game development and how some of the modern technologies adopt them. To research the importance of design patterns in game development, a small mobile game project has been done. As problems arose, a number of potentially useful design patterns were identified and analyzed. Those design patterns were practically applied to the project and their potential use with other related technologies was discussed. The paper emphasizes the important role of design patterns in game development and gives some insights into how design patterns are implemented in some of the modern middleware.

  • 73.
    Athanassiadis, Dimitris
    et al.
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Bergström, Dan
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindroos, Ola
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Nordfjell, Tomas
    Dept. of Forest Resource Management, Swedish University of Agricultural Sciences.
    Ringdahl, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Path tracking for autonomous forwarders in forest terrain2010Ingår i: Precision Forestry Symposium: developments in Precision Forestry since 2006 / [ed] Ackerman P A, Ham H, & Lu C, 2010, s. 42-43Konferensbidrag (Refereegranskat)
  • 74. Awid, Kamil
    et al.
    Cleophas, Loek
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Watson, Bruce W.
    Using Human Computation in Dead-zone based 2D Pattern Matching2016Ingår i: Prague Stringology Conference 2016 / [ed] Holub, J Zdarek, J, CZECH TECHNICAL UNIV PRAGUE , 2016, s. 22-32Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper examines the application of human computation (HC) to two-dimensional image pattern matching. The two main goals of our algorithm are to use turks as the processing units to perform an efficient pattern match attempt on a subsection of an image, and to divide the work using a version of dead-zone based pattern matching. In this approach, human computation presents an alternative to machine learning by outsourcing computationally difficult work to humans, while the dead-zone search offers an efficient search paradigm open to parallelization-making the combination a powerful approach for searching for patterns in two-dimensional images.

  • 75.
    Azimi, Seyed Ali
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Construction and Evaluation of Persistent Storage for an Online Game's Statistics2014Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Online games are gradually getting more popular than traditional video games among players due to their competitive nature, low overhead of installation, and low storage/graphic requirements. Including features such as displaying the latest game logs, top scores and best players makes these games more exciting to the passionate gamers; and this excitement makes them spend more time, try harder to achieve higher scores and be on the top of the score lists. In game industry, the game logs and related scoring data are usually stored in relational databases which grow enormously in size and have to be maintained and remain responsive as a criticalcomponent of the online games. Having a well-designed and responsive database structure is a key factor for an online game to remain functioning with the large volumes of data and thousands of concurrent transactions.

    In this research, an optimized approach is proposed toward designing a persistence layer and related databases for having an improved storage mechanism for online games. The databases of online games normally have several performance pitfalls such as data redundancy, response time, and high bandwidth usage. To overcome the latter drawbacks, some solutions have been designed and proposed in this study. As a case-study the database of a game project called Planet Mule[5]was re-designed. The new optimized persistence layer will result in a significant decrease in the response time, which eventually leads to the users’ satisfaction and popularity of the game.

    This dissertation firstly describes our proposed database design phase which includes conceptual design, logical design including normalization and physical design. Then it continues focusing on the design and optimization of queries with the goal of improving performance. To attain this goal, some standard features of DBMS systems, namely, stored procedures are utilized to optimize query performance and decrease bandwidth usage. Further, proposed stored procedures are optimized internally to achieve a lower response time. Finally, the thesis shows the implementation approach and evaluates the recently designed database layer. The development environment contains a stack of open-source technology or free tools such as Eclipse platform, MySQL workbench, Dream Coder, and MySQL debugger as a debugging and profiling tool over the queries and stored procedures; Programming was done in Java. Our experimental results show that the proposed approach outperforms the old version.

  • 76.
    Backman, Anders
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bodin, Kenneth
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bucht, Gösta
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Janlert, Lars-Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Maxhall, Marcus
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Pederson, Thomas
    Innovative Communication Group, IT University of Copenhagen.
    Sjölie, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Sondell, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Surie, Dipak
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    easyADL – Wearable Support System for Independent Life despite Dementia2006Ingår i: ACM CHI 2006 Workshop onDesigning Technology for People with Cognitive Impairments, 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    This position paper outlines the easyADL project, a two-year project investigating the possibility of using wearable technology to assist people suffering the dementia disease in performing Activities of Daily Living (ADL). An introduction to the egocentric interaction modeling framework is provided and the virtual reality based development methodology is discusssed.

  • 77.
    Backstad, Sebastian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Federated Averaging Deep Q-NetworkA Distributed Deep Reinforcement Learning Algorithm2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the telecom sector, there is a huge amount of rich data generated every day. This trend will increase with the launch of 5G networks. Telco companies are interested in analyzing their data to shape and improve their core businesses. However, there can be a number of limiting factors that prevents them from logging data to central data centers for analysis.  Some examples include data privacy, data transfer, network latency etc.

    In this work, we present a distributed Deep Reinforcement Learning (DRL) method called Federated Averaging Deep Q-Network (FADQN), that employs a distributed hierarchical reinforcement learning architecture. It utilizes gradient averaging to decrease communication cost. Privacy concerns are also satisfied by training the agent locally and only sending aggregated information to the centralized server. We introduce two versions of FADQN: synchronous and asynchronous.

    Results on the cart-pole environment show 80 times reduction in communication without any significant loss in performance. Additionally, in case of asynchronous approach, we see a great improvement in convergence.

  • 78. Badariah Asan, Noor
    et al.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Velander, Jacob
    Redzwan Mohd Shah, Syaiful
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Blokhuis, Taco J.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Voigt, Thiemo
    Augustine, Robin
    Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies2018Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, nr 9, artikel-id 2752Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

  • 79.
    Bagheri Majdi, Elmira
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    EVALUATION OF MOBILE DEVICE MANAGEMENT TOOLS AND ANALYSING INTEGRATION MODELS FOR MOBILITY ENTERPRISE2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The mobile market is growing. More and more business units, (BUs) at the multinational company ABB start considering utilizing mobility to create business value, by offering product/system enhancement and by offering new services. However, at present, there is no standard way to realize this and they struggle with the security challenges for their solution. This thesis work will focus on investigating the Mobile Device Management (MDM) market and analyze how the existing technologies address all security requirements of a mobility solution. The main goal is to investigate how multi criteria methods can be applied to facilitate the choice of the most adequate MDM tool. It needs to provide a secure common architecture and integrate with existing backend infrastructures.

    The benefits include: (1) enabling the employees to use their own mobile devices in a secure way for working with the enterprise, (2) reliably integrating a backend system for new services in enterprise mobility, and (3) providing a (proven) secure solution to control and manage mobility on MDM technology.

  • 80.
    Baranwal, Neha
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Singh, Avinash
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bensch, Suna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Extracting Primary Objects and Spatial Relations from Sentences2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In verbal human-robot interaction natural language utterances have to be grounded in visual scenes by the robot. Visual language grounding is a challenging task that includes identifying a primary object among several objects, together with the object properties and spatial relations among the objects. In this paper we focus on extracting this information from sentences only. We propose two language modelling techniques, one uses regular expressions and the other one utilizes Euclidian distance. We compare these two proposed techniques with two other techniques that utilize tree structures, namely an extended Hobb’s algorithm and an algorithm that utilizes a Stanford parse tree. A comparative analysis between all language modelling techniques shows that our proposed two approaches require less computational time than the tree-based approaches. All approaches perform good identifying the primary object and its property, but for spatial relation extraction the Stanford parse tree algorithm performs better than the other language modelling techniques. Time elapsed for the Stanford parse tree algorithm is higher than for the other techniques.

  • 81.
    Barrlund, A.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Institutionen för datavetenskap.
    Comparing stability properties of 3 methods in DAEs or ODEs with invariants1995Ingår i: Bit, Vol. 35, nr 1, s. 1-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three approaches for solving ODEs with invariants or DAEs are the constrained least squares method, the coordinate projection method and the derivative projection method. The stability properties of these three methods are compared for linear ODEs with linear invariants. There exist examples where each of the three approaches is to prefer.

  • 82.
    Barrlund, A.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Institutionen för datavetenskap.
    Efficient solution of constrained least squares problems with Kronecker product structure1998Ingår i: Siam Journal on Matrix Analysis and Applications, Vol. 19, nr 1, s. 154-160Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A computational method for efficient solution of linear constrained least squares problems with Kronecker product structure is presented. The equality constraints are assumed to be linearly independent. The computational efficiency of the method is analyzed. Conditions for uniqueness of solutions are given.

  • 83.
    Barrlund, A.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Institutionen för datavetenskap.
    On a conjecture on the closest normal matrix1998Ingår i: Mathematical Inequalities & Applications, Vol. 1, nr 3, s. 305-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Let A be a complex n x n matrix and let N-n be the set of normal n x n matrices. A conjecture is that parallel to A - N(n)parallel to(F)(2) less than or equal to n - 1/ndep(2)(A), where dep(2)(A) = parallel to A parallel to(F)(2) - Sigma(i=1)(n) lambda(i)(2)(A) and lambda(i)(A), i = 1,...,n are the eigenvalues of A. We prove that the conjecture is correct for all even n and for n = 3, 5, 7. However, for the dimensions, n = 3, 5, 6, 7, and presumably also other problem dimensions it is possible to derive sharper bounds. We also prove a bound for odd n which converges to the bound in the conjecture when n tends to infinity. The main idea in the proofs is to use LP problems with constraints based on different ways to approximate A with normal matrices.

  • 84.
    Barrlund, A.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Institutionen för datavetenskap.
    The p-relative distance is a metric2000Ingår i: Siam Journal on Matrix Analysis and Applications, Vol. 21, nr 2, s. 699-702Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The conjecture that the p-relative distance, rho(p)(alpha, <(alpha)over tilde>) = \alpha - <(alpha)over tilde>\/(p)root\alpha\(p) + \<(alpha)over tilde>\(p), is a metric is proved.

  • 85.
    Barsk, Viktor
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Time Series Search Using Traits2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Time series data occurs in many real world applications. For examplea system might have a database with a large number of time series, and a user could have a query like Find all stocks tha tbehave ”similarly” to stock A. The meaning of ”similarly” can vary between different users, use cases and domains. The goal of this thesis is to develop a method for time series search that can search based on domain specific patterns. We call these domain specific patterns traits.

    We have chosen to apply a trait based approach on top of a interest point based search method. First the search is conducted using a interest point method and then the results are ranked using the traits. The traits are extracted from sections of the time series and converted to a string representing its structure. The strings are then compared using Levenshtein distance to rank the search results. We have developed two types of traits.

    The new time series search method can be useful in many applications where a user is not looking for point-wise similarity, but rather looks at the general structure and some specific patterns. Using a trait based approach can better translate to how a user perceives time series search. The method can also yield more relevant results, since this new method can find results that a classic point-wise based search would rule out.

  • 86.
    Barth, Ruud
    et al.
    Greenhouse Horticulture, Wageningen University & Research Center.
    Baur, Jörg
    Institute of Applied Mechanics, Technische Universität München.
    Buschmann, Thomas
    Institute of Applied Mechanics, Technische Universität München.
    Edan, Yael
    Department of Industrial Engineering and Management, Ben-Gurion University of the Negev.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Nguyen, Thanh
    KU Leuven, Department of Biosystems.
    Ringdahl, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Saeys, Wouter
    KU Leuven, Department of Biosystems.
    Salinas, Carlota
    Centre for Automation and Robotics UPM-CSIC.
    Vitzrabin, Efi
    Department of Industrial Engineering and Management, Ben-Gurion University of the Negev.
    Using ROS for agricultural robotics: design considerations and experiences2014Ingår i: RHEA-2014 / [ed] Pablo Gonzalez-de-Santos and Angela Ribeiro, 2014, s. 509-518Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report on experiences of using the ROS middleware for developmentof agricultural robots. We describe software related design considerations for all maincomponents in developed subsystems as well as drawbacks and advantages with thechosen approaches. This work was partly funded by the European Commission(CROPS GA no 246252).

  • 87.
    Baskar, Jayalakshmi
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Adaptive human-agent dialogues for reasoning about health2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The aim of this research is to develop new theories, methods and technology, which enables adaptive and personalised dialogues between a human and a software agent, to handle everyday queries about health that are perceived as meaningful and useful to the human. Some of the challenges to build such human-agent dialogue system are the following. The agent needs to have knowledge about the human, the topic of the dialogue, the knowledge domain of the topic, and also about the physical and social environment. Moreover, the agent must know about itself, its role, purpose and limitations. It must know how to be cooperative and be able to behave and express with empathy while conducting a dialogue activity. In some situations, it needs to reason and make decisions about a topic together with the human and about its own behavior. To be able to do this, it needs the capability to evaluate its behavior in the context in which the dialogue takes place. These challenges are addressed by developing formal semantic models to provide the agent with tools to build their knowledge and to be able to reason and make decisions. These models were developed based on literature studies, theories of human activity, argumentation theory, personas and scenarios.

    The models were formalised and implemented using Semantic Web technology, and integrated into a human-agent dialogue system. The system was evaluated with a group of therapists and a group of elderly people, who showed curiosity and interest in having dialogues with a software agent on various topics.

    The formal models that the agent constructs are adapted to the specific situation and to the human actor participating in a dialogue. They are based on four models: a model with knowledge about the human actor, a model of itself, a domain model, and a dialogue activity model. The dialogue activity is based on argumentation schemes, which function as patterns of reasoning and for the dialogue execution. These models allow the agent and the human actor to conduct flexible and nested sub-dialogues with different purposes within a main dialogue about a topic. The agent can adapt its moves to the human actor's trail of reasoning, to the human's priorities and goals, and to some human's emotional state. A method for the agent to be able to evaluate its behavior was also developed and evaluated. The proportion of appropriate moves in relation to the local context of earlier moves in the dialogue was 90% in the pilot study, which indicates that the agent's strategies for selecting moves can be improved.

    Future research will focus on further development of reasoning methods, learning and assessment methods, and interface design. The results will be applied to additional knowledge domains to test its domain independence and will be evaluated with different groups of potential users.

  • 88.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Janols, Rebecka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering.
    Guerrero, Esteban
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Nieves, Juan Carlos
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    A Multipurpose Goal Model for Personalised Digital Coaching2017Ingår i: Agents and Multi-Agent Systems for Health Care: 10th International Workshop, A2HC 2017, São Paulo, Brazil, May 8, 2017, and International Workshop, A-HEALTH 2017, Porto, Portugal, June 21, 2017, Revised and Extended Selected Papers, Springer, 2017, Vol. 10685, s. 94-116Konferensbidrag (Refereegranskat)
    Abstract [en]

    Supporting human actors in daily living activities for improving health and wellbeing is a fundamental goal for assistive technology. The personalisation of the support provided by assistive technology in the form of digital coaching requires user models that handle potentially conflicting goals and motives. The aim of this research is to extend a motivational model implemented in an assistive technology, into a multipurpose motivational model for the human actor who is to be supported, which can be translated into a multipurpose goal model for a team of assistive agents. A team of assistive agents is outlined with supplementary goals following the human’s different properties. A method for generating multipurpose arguments relating to different motives were developed, and implemented in a human-agent dialogue system. The results are exemplified based on a use case from an earlier pilot user study of the assistive technology. Future work includes user studies to validate the model.

  • 89.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Cognitive Architecture of an Agent for Human-Agent Dialogues2014Ingår i: Highlights of Practical Applications of Heterogeneous Multi-Agent Systems: the PAAMS Collection, Springer, 2014, Vol. 430, s. 89-100Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a cognitive architecture of an intelligent agent that can have a dialogue with a human agent on health-related topics. This architecture consists of four main components, namely, the Belief Base, the Dialogue Manager, the Task Manager and the Plan Generator. Each component has sub-components that perform a set of tasks for the purpose to enable the agent to be enrolled in a dialogue. In this paper the particular sub-component of the Dialogue Manager, the Dialogue Strategy has been discussed in detail. A notion of scheme is introduced, which functions as a template with variables that are instantiated each time a state is entered. The agent’s dialogue strategy is implemented as a combination of the schemes and the state transitions that the agent makes in response to the human’s request. We used a combination of finite-state and agent-based dialogue strategies for dialogue management. This combined dialogue strategy enables a multi-topic dialogue between a human and an agent.

  • 90.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Human-Agent Dialogues and Their Purposes2017Ingår i: Proceedings of the European Conference on Cognitive Ergonomics 2017, New York, NY, USA: ACM Digital Library, 2017, s. 101-104Konferensbidrag (Refereegranskat)
    Abstract [en]

    A common conversation between an older adult and a nurse about health-related issues includes topics such as troubles with sleep, reasons for walking around nighttime, pain conditions, etc. Such a dialogue can be regarded as a "natural" dialogue emerging from the participating agents' lines of thinking, their roles, needs and motives, while switching between topics as the dialogue unfolds. The purpose of this work is to define a generic conceptual model of purposeful human-agent dialogue activity including different types of argumentation dialogues, suitable for health-related topics. This is done based on analyses of a scenario, persona and models of human behaviour. The model will be shared between the human and the agent, allowing for adaptation to the human's reasoning, needs and motives.

  • 91.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Human-Agent Dialogues on Health Topics - An Evaluation Study2015Ingår i: Highlights of practical applications of agents, multi-agent systems, and sustainability: The PAAMS Collection, PAAMS 2015, 2015, s. 28-39Konferensbidrag (Refereegranskat)
    Abstract [en]

    A common conversation between an older adult and a nurse about health-related issues includes topics such as troubles with sleep, reasons for walking around nighttime, pain conditions, etc. This dialogue emerges from the participating human's lines of thinking, their roles, needs and motives, while switching between topics as the dialogue unfolds. This paper presents a dialogue system that enables a human to engage in a dialogue with a software agent to reason about health-related issues in a home environment. The purpose of this work is to conduct a pilot evaluation study of a prototype system for human-agent dialogues, which is built upon a set of semantic models and integrated in a web application designed for older adults. Focus of the study was to receive qualitative results regarding purpose and content of the agent-based dialogue system, and to evaluate a method for the agent to evaluate its behavior based on the human agent's perception of appropriateness of moves. The participants include five therapists and 11 older adults. The results show users' feedback on the purpose of dialogues and the appropriateness of dialogues presented to them during the interaction with the software agent.

  • 92.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Semantic model for adaptive human-agent dialogues2014Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    A common conversation between an older adult and a nurse about health-related issues includes topics such as troubles with sleep, reasons for walking around nighttime, pain conditions, etc. Such a dialogue can be regarded as a "natural" dialogue emerging from the participating agents' lines of thinking, their roles, needs and motives, while switching between topics as the dialogue unfolds. The purpose of this work is to define a generic model of purposeful human-agent dialogues suitable for health-related topics. This is done based on analyses of scenarios, personas and models of human behavior. The results include four models, which need to be included in a software agent's belief base; i) a user model, ii) a model of the domain knowledge related to the topic of the dialogue, iii) an agent model, and iv) a dialogue activity model. The models were implemented into a prototype system for human-agent dialogues, which was evaluated by therapists and a group of older adults.

  • 93.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Towards personalised support for monitoring and improving health in risky environments2013Ingår i: VIII Workshop on Agents Applied in Health Care (A2HC), 2013, s. 93-104Konferensbidrag (Refereegranskat)
  • 94.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Surie, Dipak
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Yan, Chunli
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Yekeh, Farahnaz
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Personalisation and user models for support in daily living2012Ingår i: The 27th annual workshop of the Swedish Artificial Intelligence Society (SAIS), 14–15 May 2012 / [ed] Lars Karlsson, Julien Bidot, 2012, s. 7-16Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent years, the interest in developing personalised applications for home environment has grown since it has a wide reach in helping people in their daily activities. However, for our purposes the concept activities of daily living also need to include work and leisure activities not necessarily performed in home environments. In this article, we describe an ongoing effort to develop a generic framework for assessing ability and tailoring of support applications in the health domain. We also give an overview of the approaches that have been adopted for personalisation and user modelling to various application areas. Suggestions of future development are provided.

  • 95.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Yan, Chunli
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    User's control of personalised intelligent environments supporting health2013Ingår i: Intelligent Environments (IE), 2013 9th International Conference on, IEEE Computer Society, 2013, s. 270-273Konferensbidrag (Refereegranskat)
    Abstract [en]

    This research project aims at supporting workers in the mining and construction industries and older adults at home, in monitoring the risks of their daily work or living situation. A goal is to create awareness in the individual about risks and how to decrease risks. Methods and knowledge-based applications are developed, which synthesise knowledge about the user, the user’s activities, the environment and generic domain knowledge for the purpose of providing tailored support and advice to individuals. This knowledge is also what the user can relate to, interact with and control through different methods. In this paper we investigate different approaches to user control of intelligent environments and propose a dialogue-based method for user control.

  • 96.
    Baskar, Jayalakshmi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Yan, Chunli
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Instrument-Oriented Approach to Detecting and Representing Human Activity for Supporting Executive Functions and Learning2017Ingår i: Proceedings of the European Conference on Cognitive Ergonomics 2017, New York, NY, USA: ACM Digital Library, 2017, s. 105-112Konferensbidrag (Refereegranskat)
    Abstract [en]

    The goal of this study is to develop a computer-interpretable model for activity detection and representation, based on existing informal models of how humans perform activity. Appropriate detection of purposeful human activity is an essential functionality of active assistive technology aiming at providing tailored support to individuals for improving activity performance and completion. The main contribution is the design of a model for detection and representation of human activities based on three categories of instruments, which is implemented as two generic and supplementary terminology models: an event ontology and a core ontology. The core ontology is extended for each new knowledge domain into a domain ontology. The model builds the base for personalization of services generated by the cooperative reasoning performed by a human collaborating with an intelligent and social software agent. Ongoing and future work includes user studies in the different application domains.

  • 97. Bauer,, André
    et al.
    Herbst, Nikolas
    Spinner, Simon
    Ali-Eldin, Ahmed
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kounev, Samuel
    Chameleon: A Hybrid, Proactive Auto-Scaling Mechanism on a Level-Playing Field2018Ingår i: IEEE Transactions on Parallel and Distributed Systems, ISSN 1045-9219, E-ISSN 1558-2183Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Auto-scalers for clouds promise stable service quality at low costs when facing changing workload intensity. The major public cloud providers provide trigger-based auto-scalers based on thresholds. However, trigger-based auto-scaling has reaction times in the order of minutes. Novel auto-scalers from literature try to overcome the limitations of reactive mechanisms by employing proactive prediction methods. However, the adoption of proactive auto-scalers in production is still very low due to the high risk of relying on a single proactive method.

  • 98. Bauer, André
    et al.
    Herbst, Nikolas
    Spinner, Simon
    Ali-Eldin, Ahmed
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. UMass, Amherst, MA, USA.
    Kounev, Samuel
    Chameleon: A Hybrid, Proactive Auto-Scaling Mechanism on a Level-Playing Field2019Ingår i: IEEE Transactions on Parallel and Distributed Systems, ISSN 1045-9219, E-ISSN 1558-2183, Vol. 30, nr 4, s. 800-813Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Auto-scalers for clouds promise stable service quality at low costs when facing changing workload intensity. The major public cloud providers provide trigger-based auto-scalers based on thresholds. However, trigger-based auto-scaling has reaction times in the order of minutes. Novel auto-scalers from literature try to overcome the limitations of reactive mechanisms by employing proactive prediction methods. However, the adoption of proactive auto-scalers in production is still very low due to the high risk of relying on a single proactive method. This paper tackles the challenge of reducing this risk by proposing a new hybrid auto-scaling mechanism, called Chameleon, combining multiple different proactive methods coupled with a reactive fallback mechanism. Chameleon employs on-demand, automated time series-based forecasting methods to predict the arriving load intensity in combination with run-time service demand estimation to calculate the required resource consumption per work unit without the need for application instrumentation. We benchmark Chameleon against five different state-of-the-art proactive and reactive auto-scalers one in three different private and public cloud environments. We generate five different representative workloads each taken from different real-world system traces. Overall, Chameleon achieves the best scaling behavior based on user and elasticity performance metrics, analyzing the results from 400 hours aggregated experiment time.

  • 99. Baum, Seth D.
    et al.
    Armstrong, Stuart
    Ekenstedt, Timoteus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Häggström, Olle
    Hanson, Robin
    Kuhlemann, Karin
    Maas, Matthijs M.
    Miller, James D.
    Salmela, Markus
    Sandberg, Anders
    Sotala, Kaj
    Torres, Phil
    Turchin, Alexey
    Yampolskiy, Roman V.
    Long-term trajectories of human civilization2019Ingår i: Foresight, ISSN 1463-6689, E-ISSN 1465-9832, Vol. 21, nr 1, s. 53-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: This paper aims to formalize long-term trajectories of human civilization as a scientific and ethical field of study. The long-term trajectory of human civilization can be defined as the path that human civilization takes during the entire future time period in which human civilization could continue to exist.

    Design/methodology/approach: This paper focuses on four types of trajectories: status quo trajectories, in which human civilization persists in a state broadly similar to its current state into the distant future; catastrophe trajectories, in which one or more events cause significant harm to human civilization; technological transformation trajectories, in which radical technological breakthroughs put human civilization on a fundamentally different course; and astronomical trajectories, in which human civilization expands beyond its home planet and into the accessible portions of the cosmos.

    Findings: Status quo trajectories appear unlikely to persist into the distant future, especially in light of long-term astronomical processes. Several catastrophe, technological transformation and astronomical trajectories appear possible.

    Originality/value: Some current actions may be able to affect the long-term trajectory. Whether these actions should be pursued depends on a mix of empirical and ethical factors. For some ethical frameworks, these actions may be especially important to pursue.

  • 100.
    Baydan, Berker
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Inferring Human Situation using Proximity to Smart Objects2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Human proximity tracking and human situation inference are exploited for comprehending human interaction with objects in kitchen. The importance of this study is to offer interactive and personalized kitchen environment for elderly and disabled people. Also, this smart environment allows for independent living for elderly and disabled people. This study proposes human proximity tracking and inferring human situation in smart environment. A precision of 100% and a recall of 65.22% were obtained from the result of proximity tracking. The result of precision indicates that human proximity tracking works accurately in kitchen environment. Interms of human situation inference, the result of accuracy of fuzzy logic system was obtained as above 96% precision in each situative space model set, except recognizable set. This result shows that system works well with a few exceptions in relation to human situation inference.

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