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  • 1.
    Abedan Kondori, Farid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Yousefi, Shahrouz
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Liu, Li
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Li, Haibo
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Head operated electric wheelchair2014Ingår i: IEEE Southwest Symposium on Image Analysis and Interpretation (SSIAI 2014), IEEE , 2014, s. 53-56Konferensbidrag (Refereegranskat)
    Abstract [en]

    Currently, the most common way to control an electric wheelchair is to use joystick. However, there are some individuals unable to operate joystick-driven electric wheelchairs due to sever physical disabilities, like quadriplegia patients. This paper proposes a novel head pose estimation method to assist such patients. Head motion parameters are employed to control and drive an electric wheelchair. We introduce a direct method for estimating user head motion, based on a sequence of range images captured by Kinect. In this work, we derive new version of the optical flow constraint equation for range images. We show how the new equation can be used to estimate head motion directly. Experimental results reveal that the proposed system works with high accuracy in real-time. We also show simulation results for navigating the electric wheelchair by recovering user head motion.

  • 2.
    Abedin, Md Reaz Ashraful
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bensch, Suna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Self-supervised language grounding by active sensing combined with Internet acquired images and text2017Ingår i: Proceedings of the Fourth International Workshop on Recognition and Action for Scene Understanding (REACTS2017) / [ed] Jorge Dias George Azzopardi, Rebeca Marf, Málaga: REACTS , 2017, s. 71-83Konferensbidrag (Refereegranskat)
    Abstract [en]

    For natural and efficient verbal communication between a robot and humans, the robot should be able to learn names and appearances of new objects it encounters. In this paper we present a solution combining active sensing of images with text based and image based search on the Internet. The approach allows the robot to learn both object name and how to recognise similar objects in the future, all self-supervised without human assistance. One part of the solution is a novel iterative method to determine the object name using image classi- fication, acquisition of images from additional viewpoints, and Internet search. In this paper, the algorithmic part of the proposed solution is presented together with evaluations using manually acquired camera images, while Internet data was acquired through direct and reverse image search with Google, Bing, and Yandex. Classification with multi-classSVM and with five different features settings were evaluated. With five object classes, the best performing classifier used a combination of Pyramid of Histogram of Visual Words (PHOW) and Pyramid of Histogram of Oriented Gradient (PHOG) features, and reached a precision of 80% and a recall of 78%.

  • 3.
    Adlerborn, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Högpresterande beräkningscentrum norr (HPC2N).
    Parallel Algorithms and Library Software for the Generalized Eigenvalue Problem on Distributed Memory Computer Systems2016Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    We present and discuss algorithms and library software for solving the generalized non-symmetric eigenvalue problem (GNEP) on high performance computing (HPC) platforms with distributed memory. Such problems occur frequently in computational science and engineering, and our contributions make it possible to solve GNEPs fast and accurate in parallel using state-of-the-art HPC systems. A generalized eigenvalue problem corresponds to finding scalars y and vectors x such that Ax = yBx, where A and B are real square matrices. A nonzero x that satisfies the GNEP equation is called an eigenvector of the ordered pair (A,B), and the scalar y is the associated eigenvalue. Our contributions include parallel algorithms for transforming a matrix pair (A,B) to a generalized Schur form (S,T), where S is quasi upper triangular and T is upper triangular. The eigenvalues are revealed from the diagonals of S and T. Moreover, for a specified set of eigenvalues an associated pair of deflating subspaces can be computed, which typically is requested in various applications. In the first stage the matrix pair (A,B) is reduced to a Hessenberg-triangular form (H,T), where H is upper triangular with one nonzero subdiagonal and T is upper triangular, in a finite number of steps. The second stage reduces the matrix pair further to generalized Schur form (S,T) using an iterative QZ-based method. Outgoing from a one-stage method for the reduction from (A,B) to (H,T), a novel parallel algorithm is developed. In brief, a delayed update technique is applied to several partial steps, involving low level operations, before associated accumulated transformations are applied in a blocked fashion which together with a wave-front task scheduler makes the algorithm scale when running in a parallel setting. The potential presence of infinite eigenvalues makes a generalized eigenvalue problem ill-conditioned. Therefore the parallel algorithm for the second stage, reduction to (S,T) form, continuously scan for and robustly deflate infinite eigenvalues. This will reduce the impact so that they do not interfere with other real eigenvalues or are misinterpreted as real eigenvalues. In addition, our parallel iterative QZ-based algorithm makes use of multiple implicit shifts and an aggressive early deflation (AED) technique, which radically speeds up the convergence. The multi-shift strategy is based on independent chains of so called coupled bulges and computational windows which is an important source of making the algorithm scalable. The parallel algorithms have been implemented in state-of-the-art library software. The performance is demonstrated and evaluated using up to 1600 CPU cores for problems with matrices as large as 100000 x 100000. Our library software is described in a User Guide. The software is, optionally, tunable via a set of parameters for various thresholds and buffer sizes etc. These parameters are discussed, and recommended values are specified which should result in reasonable performance on HPC systems similar to the ones we have been running on.

  • 4.
    Adlerborn, Björn
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Högpresterande beräkningscentrum norr (HPC2N).
    Kågström, Bo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Högpresterande beräkningscentrum norr (HPC2N).
    Kressner, Daniel
    A parallel QZ algorithm for distributed memory HPC systems2014Ingår i: SIAM Journal on Scientific Computing, ISSN 1064-8275, E-ISSN 1095-7197, Vol. 36, nr 5, s. C480-C503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Appearing frequently in applications, generalized eigenvalue problems represent one of the core problems in numerical linear algebra. The QZ algorithm of Moler and Stewart is the most widely used algorithm for addressing such problems. Despite its importance, little attention has been paid to the parallelization of the QZ algorithm. The purpose of this work is to fill this gap. We propose a parallelization of the QZ algorithm that incorporates all modern ingredients of dense eigensolvers, such as multishift and aggressive early deflation techniques. To deal with (possibly many) infinite eigenvalues, a new parallel deflation strategy is developed. Numerical experiments for several random and application examples demonstrate the effectiveness of our algorithm on two different distributed memory HPC systems.

  • 5.
    Ahmad, Farooq
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Lindgren, Helena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Selection of foundational ontology for collaborative knowledge modeling in healthcare domain2010Ingår i: Artificial intelligence: methodology, systems, and applications / [ed] Dicheva, Darina; Dochev, Danail, Springer Berlin/Heidelberg, 2010, s. 261-262Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ontology design is an important process for structuring knowledge to be reused in different projects in the health domain. In this paper, we describe an ontology design for the collaborative knowledge building system ACKTUS to be used for developing personalized knowledge applications for different domains. Different foundational ontologies were compared with respect to selected criteria considered vital for the project, such as modularity and descriptiveness.

  • 6. Aichroth, Patrick
    et al.
    Weigel, Christian
    Kurz, Thomas
    Stadler, Horst
    Drewes, Frank
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Björklund, Johanna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Schlegel, Kai
    Berndl, Emanuel
    Perez, Antonio
    Bowyer, Alex
    Volpini, Andrea
    MICO - MEDIA IN CONTEXT2015Ingår i: 2015 IEEE International Conference on Multimedia & Expo Workshops (ICMEW), 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The abundance of digital content requires cost-effective technologies to extract the hidden meaning from media objects. However, current approaches fail to deal with the challenges related to cross-media analysis, metadata publishing, querying and recommendation that are necessary to overcome this challenge. In this paper, we describe the EU project MICO (Media in Context) which aims to provide the necessary technologies based on open-source software (OSS) core components.

  • 7.
    Alaqra, Alaa
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Cell-phone Travel Planner GUI for SpaceTime2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Global positioning systems have been having an increasing interest recently and been integrated and used in many applications to service positioning, navigation and travel planning. This project has set to design and test an interface of a travel planner for cell phones. A pre-study was made to investigate other travel planners to help the design of this application that has targeted a user friendly interface that people can use regardless of their background. A special feature, carpooling, has been introduced to ease the environmental, economical, and social aspects of navigation. The test was done as walk-through mockup images case scenarios. The test subjects were pleased with the interface’s friendliness, invoked carpooling issues, presented contradictory opinions regarding the interface's design, and offered future integration with other applications suggestions all of which were discussed. Overall, the test results were positive and few problems with the overall design were identified. A future study with more participants and a deeper analysis of the interface would be one way to further investigate the proposed interface.

  • 8.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Dignum, Virginia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    The Glass Box Approach: Verifying Contextual Adherence to Values2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Artificial Intelligence (AI) applications are beingused to predict and assess behaviour in multiple domains, such as criminal justice and consumer finance, which directly affect human well-being. However, if AI is to be deployed safely, then people need to understand how the system is interpreting and whether it is adhering to the relevant moral values. Even though transparency is often seen as the requirement in this case, realistically it might notalways be possible or desirable, whereas the needto ensure that the system operates within set moral bounds remains.

    In this paper, we present an approach to evaluate the moral bounds of an AI system based on the monitoring of its inputs and outputs. We place a ‘Glass Box’ around the system by mapping moral values into contextual verifiable norms that constrain inputs and outputs, in such a way that if these remain within the box we can guarantee that the system adheres to the value(s) in a specific context. The focus on inputs and outputs allows for the verification and comparison of vastly different intelligent systems–from deep neural networks to agent-based systems–whereas by making the context explicit we exposethe different perspectives and frameworks that are taken into account when subsuming moral values into specific norms and functionalities. We present a modal logic formalisation of the Glass Box approach which is domain-agnostic, implementable, and expandable.

  • 9.
    Aler Tubella, Andrea
    et al.
    Umeå universitet.
    Theodorou, Andreas
    Umeå universitet.
    Dignum, Frank
    Umeå universitet.
    Dignum, Virginia
    Umeå universitet.
    Governance by Glass-Box: Implementing Transparent Moral Bounds for AI Behaviour2019Ingår i: Proceedings of the 28th International Joint Conference on Artificial Intelligence, 2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Artificial Intelligence (AI) applications are being used to predict and assess behaviour in multiple domains which directly affect human well-being. However, if AI is to improve people’s lives, then people must be able to trust it, by being able to understand what the system is doing and why. Although transparency is often seen as the requirementin this case, realistically it might not always be possible, whereas the need to ensure that the system operates within set moral bounds remains.

    In this paper, we present an approach to evaluate the moral bounds of an AI system based on the monitoring of its inputs and outputs. We place a ‘Glass-Box’ around the system by mapping moral values into explicit verifiable norms that constrain inputs and outputs, in such a way that if these remain within the box we can guarantee that the system adheres to the value. The focus on inputs and outputs allows for the verification and comparison of vastly different intelligent systems; from deep neural networks to agent-based systems.

    The explicit transformation of abstract moral values into concrete norms brings great benefits interms of explainability; stakeholders know exactly how the system is interpreting and employing relevant abstract moral human values and calibrate their trust accordingly. Moreover, by operating at a higher level we can check the compliance of the system with different interpretations of the same value.

  • 10.
    Ali-Eldin, Ahmed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kihl, Maria
    Dept. of Electrical and Information Technology, Lund University, Lund, Sweden.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Efficient provisioning of bursty scientific workloads on the cloud using adaptive elasticity control2012Ingår i: Proceedings of the 3rd workshop on Scientific Cloud Computing Date, Association for Computing Machinery (ACM), 2012, s. 31-40Konferensbidrag (Refereegranskat)
    Abstract [en]

    Elasticity is the ability of a cloud infrastructure to dynamically change theamount of resources allocated to a running service as load changes. We build anautonomous elasticity controller that changes the number of virtual machinesallocated to a service based on both monitored load changes and predictions offuture load. The cloud infrastructure is modeled as a G/G/N queue. This modelis used to construct a hybrid reactive-adaptive controller that quickly reactsto sudden load changes, prevents premature release of resources, takes intoaccount the heterogeneity of the workload, and avoids oscillations. Using simulations with Web and cluster workload traces, we show that our proposed controller lowers the number of delayed requests by a factor of 70 for the Web traces and 3 for the cluster traces when compared to a reactive controller. Ourcontroller also decreases the average number of queued requests by a factor of 3 for both traces, and reduces oscillations by a factor of 7 for the Web traces and 3 for the cluster traces. This comes at the expense of between 20% and 30% over-provisioning, as compared to a few percent for the reactive controller.

  • 11.
    Alin, Lars
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Object Tracking withIphone 3Gs2010Självständigt arbete på avancerad nivå (magisterexamen), 30 poäng / 45 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In June of 2007 Apple Inc. released the smartphone Iphone. It was a groundbreaking success that set a new standard for what a smartphone should be able to do. Apple has improved the Iphone every year since then and the 3Gs is the newest Iphone model. As the phones have improved, both when looking at hardware and software, the applications have improved as well. The Iphone 3Gs provides the possibility to use the camera as an application background and with that the possibility to analyze the surroundings, making it possible to track objects that the phone is pointed towards.This thesis examines how object tracking can be implemented in applications for Iphone 3Gs as well as providing a survey of four different areas of use that have been implemented in Xcode: an augmented reality car game, a letter tracking application, a face recognition application and an object recognition application.

  • 12.
    Al-Naser, Mohammad
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Söderström, Ulrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Reconstruction of occluded facial images using asymmetrical Principal Component Analysis2012Ingår i: Integrated Computer-Aided Engineering, ISSN 1069-2509, E-ISSN 1875-8835, Vol. 19, nr 3, s. 273-283Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When only non-occluded image parts are available for facial images it is difficult or impossible to correctly recognize the person in the image. The problem addressed in this work is reconstruction of the occluded parts in facial images; e. g. eyes covered with sunglasses. Asymmetrical Principal Component Analysis (aPCA) allows estimation of occluded facial parts based on the content of the facial parts which are visible. aPCA is used to estimate full non-occluded faces from 3 kinds of occlusion with 2 different reconstruction methods in this work and we present the results with both objective and subjective evaluation. The subjective evaluation shows that clear and sharp image regions are preferred even if this results in visible edges in the images. The method also performs well when a different facial expression than the one in the database is used to calculate the reconstruction parameters.

  • 13.
    Andersson, Marcus
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Complexity and problem solving: A tale of two systems2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med den här uppsatsen är att undersöka om en ökande komplexitet på ett problem, innebär en skillnad för ett lärande system med två samverkande. De två samverkande delarna som används är från “Actor” och “Critic”, som kommer ifrån algoritmen “Actor-Critic”. som implementeras med hjälp av ramverket “Reinforcement learning”. Resultaten bekräftar att det inte verkar vara någon skillnad i relativ effektivitet mellan “Actor” och “Critic” när komplexiteten ändras mellan två problem. Detta kan bero på tekniska svårigheter att jämföra miljöerna i experimentet och algoritmerna som används. Om det finns problem med jämförelserna skulle skillnaden i komplexitet vara icke-uniform på ett obestämbart sätt, och att kunna göra jämförelser blir därför svårt. Däremot om skillnaden i komplexitet är uniform, skulle det kunna tyda på det kanske finns en skillnad i hur “Actor” och “Critic” hanterar olika typer av komplexitet. Vidare studier med kontrollerade ökningar för komplexiteten är nödvändiga för att fastställa hur “Actor-Crtic” algoritmen samverkar med skillnader i komplexitet. I diskussionen presenteras iden att använda Actor-Critic modellen för att förstå metoder för psykologiska behandlingar bättre.

  • 14.
    Andersson, Ola
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Institutionen för datavetenskap.
    Threat, risk, and vulnerabilityanalyses during the developmentof IT systems in the SwedishArmed Forces2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This master’s thesis describes how two models from the Swedish Armed Forces; the risk management model and the IT lifecycle model can be combined. An example is then presented for how the risk management model can be extended for threats, risks, and vulnerabilities related to information technology. The combination and extension of the models are based on a literature study that lists and compares models and methods for threat, risk, andvulnerability analyses, as well as an analysis of threats related to information technology. From the combined and extended model, a design proposal for how to implement the identified functionality was identified. Based on an evaluation that showed that the program NTE and the plugin EASTER were suitable as the foundation for this implementation, the program NTE and the plugin EASTER were extended with further functionality and resulted in the implementation of the plugin ASCENSION. This was evaluated and resulted in ideas for a possible re-design and examples of the future potential of ASCENSION.

  • 15.
    Andersson, Pehr
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Hedman, Leif
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Center for Surgical Sciences, Karolinska Institutet at Huddinge University Hospital.
    Enochsson, Lars
    Ström, Pär
    Kjellin, Ann
    Westman, Bo
    Felländer-Tsai, Li
    Working memory and virtual endoscopy simulation2004Ingår i: Proceedings of the twenty-sixth annual conference of the cognitive science society / [ed] Forbus, K; Gentner, D; Regier, T, Mahwah: Lawrence Erlbaum Associates, 2004, s. 1519-1519Konferensbidrag (Refereegranskat)
  • 16.
    Andersson, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Model based object finding in occluded cluttered environments2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aim of the thesis is object finding in occluded and cluttered environment using computer vision techniques and robot motion. Difficulties of the object finding are 1. finding objects at hidden area and 2. finding unrecognized objects. For solving the difficulties, two methods were developed, one is for finding objects in occluded cluttered environments using model based object finding and the other to increase the robustness in object finding by identifying known objects that are unidentified. The goal was to search occluded areas with the bumblebee2 stereo camera to be able to identify all known objects in the environment by removing all visible known objects To identify known objects SURF [9] was used and to be able to remove the identified objects their location first needed to be localized. To localize the object‘s x and y coordinate the information from SURF [9] was used, and the distance coordinate z is calculated using the depth image from the stereo camera. The method to identify objects the SURF [9] algorithm had missed to identify uses a method to find unknown segments in the environment. By using a push motion on the segments to change their angle it can remove possible light reflections and the object can be identified. The results of this research show that the method can find objects in occluded cluttered areas and it can also identified missed known objects.

  • 17.
    Andersson, Rickard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Pseudo-optimal strategies in no-limit poker2006Ingår i: ICGA Journal, ISSN 1389-6911, Vol. 29, nr 3, s. 143-149Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Games have always been a strong driving force in Artificial Intelligence. In the last ten years huge improvements has been made in perfect information games like chess and Othello. The strongest computer agents can nowadays beat the strongest human players. This is not the case for imperfect information games such as poker and bridge where creating an expert computer player has shown to be much harder. Previous research in poker has either addressed limit poker or simplified variations of poker games. This paper tries to extend known techniques successfully used in limit poker to no-limit. No-limit poker increases the size of the game tree drastically. To reduce the complexity an abstracted model of the game is created. Finding an optimal strategy for the new model is now a minimization problem using linear programming techniques. The result is a set of pseudo-optimal strategies for no-limit Texas Hold'em. A bot named AGGROBOT was built from these strategies which perform well as long as the players' stack sizes are fairly small.

  • 18.
    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.

  • 19.
    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.

  • 20.
    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.

  • 21. Ans, Muhammad
    et al.
    Iqbal, Javed
    Eliasson, Bertil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Saif, Muhammad Jawwad
    Javed, Hafiz Muhammad Asif
    Ayub, Khurshid
    Designing of non-fullerene 3D star-shaped acceptors for organic solar cells2019Ingår i: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 25, nr 5, artikel-id 129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The design and fabrication of solar cells have recently witnessed the exploration of non-fullerene-based acceptor molecules for higher efficiency. In this study, the optical and electronic properties of four new three-dimensional (3D) star-shaped acceptor molecules (M1, M2, M3, and M4) are evaluated for use as acceptor molecules in organic solar cells. These molecules contain a triphenylamine donor core with diketopyrrolopyrrole acceptor arms linked via a thiophene bridge unit. Molecules M1–M4 are characterized by different end-capped acceptor moieties, including 2-(5-methylene-6-oxo-5,6-dihydrocyclopenta-b-thiophen-4-ylidene)malononitrile (M1), 2-(2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M2), 2-(5-methyl-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M3), and 3-methyl-5-methylnene-thioxothiazolidin-4-one (M4). The properties of the newly designed molecules were compared with a well-known reference compound R, which was recently reported as an excellent acceptor molecule for organic solar cells. Molecules M1–M4 exhibit suitable frontier molecular orbital patterns for charge mobility. M2 shows maximum absorption (λmax) at 846.8 nm in dichloromethane solvent, which is ideal for the design of transparent solar cells. A strong electron withdrawing end-capped acceptor causes a red shift in absorption spectra. All molecules are excellent for hole mobility due to a lower value of λh compared to the reference R.

  • 22.
    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)
  • 23. 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.

  • 24.
    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.

  • 25.
    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.

  • 26.
    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.

  • 27.
    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.

  • 28. 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.

  • 29. Bae, Seung-Hee
    et al.
    Halperin, Daniel
    West, Jevin
    Rosvall, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Howe, Bill
    Scalable Flow-Based Community Detection for Large-Scale Network Analysis2013Ingår i: 2013 IEEE 13TH INTERNATIONAL CONFERENCE ON DATA MINING WORKSHOPS (ICDMW) / [ed] Ding, W Washio, T Xiong, H Karypis, G Thuraisingham, B Cook, D Wu, X, IEEE, 2013, s. 303-310Konferensbidrag (Refereegranskat)
    Abstract [en]

    Community-detection is a powerful approach to uncover important structures in large networks. Since networks often describe flow of some entity, flow-based community-detection methods are particularly interesting. One such algorithm is called Infomap, which optimizes the objective function known as the map equation. While Infomap is known to be an effective algorithm, its serial implementation cannot take advantage of multicore processing in modern computers. In this paper, we propose a novel parallel generalization of Infomap called RelaxMap. This algorithm relaxes concurrency assumptions to avoid lock overhead, achieving 70% parallel efficiency in shared-memory multicore experiments while exhibiting similar convergence properties and finding similar community structures as the serial algorithm. We evaluate our approach on a variety of real graph datasets as well as synthetic graphs produced by a popular graph generator used for benchmarking community detection algorithms. We describe the algorithm, the experiments, and some emerging research directions in high-performance community detection on massive graphs.

  • 30.
    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.

  • 31.
    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.

  • 32.
    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.

  • 33.
    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.

  • 34.
    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.

  • 35.
    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)
  • 36.
    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.

  • 37.
    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.

  • 38.
    Bayuh Lakew, Ewnetu
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Xu, Lei
    Hernandez-Rodriguez, Francisco
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Pahl, Claus
    A Tree-based Protocol for Enforcing Quotas in Clouds2014Ingår i: 2014 IEEE WORLD CONGRESS ON SERVICES (SERVICES), 2014, s. 279-286Konferensbidrag (Refereegranskat)
    Abstract [en]

    Services are increasingly being hosted on cloud nodes to enhance their performance and increase their availability. The virtually unlimited availability of cloud resources enables service owners to consume resources without quantitative restrictions, paying only for what they use. To avoid cost overruns, resource consumption must be controlled and capped when necessary. We present a distributed tree-based protocol for managing quotas in clouds that minimizes communication overheads and reduces the time required to determine whether a quota has been exhausted. Experimental evaluation shows that our protocol reduces communication costs by 42% relative to a distributed baseline solution and is up to 15 times faster.

  • 39. Beco, S
    et al.
    Maraschini, A
    Pacini, F
    Biran, O
    Breitgand, O
    Meth, K
    Rochwerger, B
    Salant, E
    Silvera, E
    Tal, S
    Wolfsthal, Y
    Yehuda, M
    Caceres, J
    Hierro, J
    Emmerich, W
    Galis, A
    Edblom, Lennart
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Henriksson, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hernandez, Francisco
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hohl, A
    Levy, E
    Sampaio, A
    Scheuermann, B
    Wusthoff, M
    Latanicki, J
    Lopez, G
    Marin-Frisonroche, J
    Dorr, A
    Ferstl, F
    Huedo, E
    Llorente, I
    Montero, R
    Massonet, P
    Naqvi, S
    Dallons, G
    Pezz, M
    Puliafito, A
    Ragusa, C
    Scarpa, M
    Muscella, S
    Cloud Computing and RESERVOIR project2009Ingår i: Nuovo Cimento C, ISSN ISSN 1124-1896, Vol. 32, nr 2, s. 99-103Artikel i tidskrift (Refereegranskat)
  • 40. Belabbaci, Ahlem
    et al.
    Cherroun, Hadda
    Cleophas, Loek
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. FASTAR Research Group, Stellenbosch University, South Africa.
    Ziadi, Djelloul
    Tree pattern matching from regular tree expressions2018Ingår i: Kybernetika (Praha), ISSN 0023-5954, E-ISSN 1805-949X, Vol. 54, nr 2, s. 221-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work we deal with tree pattern matching over ranked trees, where the pattern set to be matched against is defined by a regular tree expression. We present a new method that uses a tree automaton constructed inductively from a regular tree expression. First we construct a special tree automaton for the regular tree expression of the pattern E, which is somehow a generalization of Thompson automaton for strings. Then we run the constructed automaton on the subject tree t. The pattern matching algorithm requires an O(vertical bar t vertical bar vertical bar E vertical bar) time complexity, where vertical bar t vertical bar is the number of nodes of t and vertical bar E vertical bar is the size of the regular tree expression E. The novelty of this contribution besides the low time complexity is that the set of patterns can be infinite, since we use regular tree expressions to represent patterns.

  • 41. Ben Yehuda, M.
    et al.
    Biran, O.
    Breitgand, D.
    Meth, K.
    Rochwerger, B.
    Salant, E.
    Silvera, E.
    Tal, S.
    Wolfsthal, Y.
    Cáceres, J.
    Hierro, J.
    Emmerich, W.
    Galis, A.
    Edblom, Lennart
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Elmroth, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Henriksson, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hernández, Francisco
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Tordsson, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hohl, A.
    Levy, E.
    Sampaio, A.
    Scheuermann, B.
    Wusthoff, M.
    Latanicki, J.
    Lopez, G.
    Marin-Frisonroche, J.
    Dörr, A.
    Ferstl, F.
    Beco, S.
    Pacini, F.
    Llorente, I.
    Montero, R.
    Huedo, E.
    Massonet, P.
    Naqvi, S.
    Dallons, G.
    Pezzé, M.
    Puliato, A.
    Ragusa, C.
    Scarpa, M.
    Muscella, S.
    RESERVOIR: An ICT Infrastructure for Reliable and Effective Delivery of Services as Utilities2008Rapport (Övrigt vetenskapligt)
  • 42.
    Bensch, Suna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Graph Transformation for Incremental Natural Language Analysis.2014Övrigt (Övrigt vetenskapligt)
  • 43.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Björklund, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, Frank
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Algorithmic properties of Millstream systems2010Ingår i: Developments in Language Theory: 14th International Conference, DLT 2010 / [ed] Sheng Yu, Springer Berlin/Heidelberg, 2010, s. 54-65Konferensbidrag (Refereegranskat)
    Abstract [en]

    Millstream systems have recently been proposed as a formalization of the linguistic idea that natural language should be described as a combination of different modules related by interfaces. In this paper we investigate algorithmic properties of Millstream systems having regular tree grammars as modules and MSO logic as interface logic. We focus on the so-called completion problem: Given trees generated by a subset of the modules, can they be completed into a valid configuration of the Millstream system?

  • 44.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bordihn, Henning
    Information, codes and languages: Essays dedicated to Helmut Jürgensen on the occassion of his 75th birthday – Preface2018Ingår i: Journal of Automata, Languages and Combinatorics, ISSN 1430-189X, Vol. 23, nr 1–3, s. 2s. 3-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This special issue is dedicated to Professor Helmut Jürgensen on the occasion of his 75th birthday and in appreciation of his scientific work and his impact as teacher, mentor, and person. The sixteen papers in this special issue were submitted by invitation of the guest editors. Each paper was reviewed by at least two referees. The authors of the papers in this special issue are collaborators, co-authors, or scientific descendents of Helmut Jürgensen.

  • 45.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Bordihn, Henning
    Institut für Informatik, Universität Potsdam.
    Holzer, Markus
    Institut für Informatik, Universität Giessen.
    Kutrib, Martin
    Institut für Informatik, Universität Giessen.
    On input-revolving deterministic and nondeterministic finite automata2009Ingår i: Information and Computation, ISSN 0890-5401, E-ISSN 1090-2651, Vol. 207, s. 1140-1155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce and investigate input-revolving finite automata, which are (nondeterministic) finite state automata with additional ability to shift the remaining part of the input. Three different modes of shifting are considered, namely revolving to the left, revolving to the right, and circular-interchanging. We investigate the computational capacities of these three types of automata and their deterministic variants, comparing any of the six classes of automata with each other and with further classes of well-known automata. In particular, it is shown that nondeterminism is better than determinism, that is, for all three modes of shifting there is a language accepted by the nondeterministic model but not accepted by any determinstic automaton of the same type. Concerning the closure properties most of the deterministic language families studied are not closed under standard operations. For example, we show that the family of languages accepted by deterministic right-revolving finite automata is an anti-AFL which is not closed under reversal and intersection.

  • 46.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, Frank
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Millstream Systems: a formal model for linking language modules by interfaces2010Ingår i: Proc. ACL 2010 Workshop on Applications of Tree Automata in Natural Language Processing (ATANLP 2010), The Association for Computer Linguistics , 2010Konferensbidrag (Refereegranskat)
  • 47.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, FrankUmeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Proceedings of Umeå's 16th student conference in computing science: USCCS 20132013Proceedings (redaktörskap) (Övrigt vetenskapligt)
  • 48.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, FrankUmeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.Freund, RudolfTechnical University Vienna.Otto, FriedrichTechnical University Kassel.
    Fifth Workshop on Non-Classical Models for Automata and Applications - NCMA 2013, Umeå, Sweden, August 13 - August 14, 2013, Proceedings2013Proceedings (redaktörskap) (Refereegranskat)
  • 49.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, Frank
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hellström, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Grammatical Inference of Graph Transformation Rules2015Ingår i: Proceedings of the 7th Workshop on Non-Classical Modelsof Automata and Applications (NCMA 2015), Austrian Computer Society , 2015, s. 73-90Konferensbidrag (Refereegranskat)
  • 50.
    Bensch, Suna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Drewes, FrankUmeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.Hirvensalo, MikaOtto, Friedrich
    Fundamenta Informaticae: special issue2015Proceedings (redaktörskap) (Övrigt vetenskapligt)
1234567 1 - 50 av 829
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