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  • 1.
    Abbasi, Ahtisham Fazeel
    et al.
    German Research Center for Artificial Intelligence (DFKI), Kaiserslautern, Germany; University of Kaiserslautern-Landau, Kaiserslautern (RPTU), Germany.
    Asim, Muhammad Nabeel
    German Research Center for Artificial Intelligence (DFKI), Kaiserslautern, Germany.
    Trygg, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Sartorius Corporate Research, Sartorius Stedim Data Analytics, Umeå, Sweden.
    Dengel, Andreas
    German Research Center for Artificial Intelligence (DFKI), Kaiserslautern, Germany; University of Kaiserslautern-Landau, Kaiserslautern (RPTU), Germany.
    Ahmed, Sheraz
    German Research Center for Artificial Intelligence (DFKI), Kaiserslautern, Germany.
    Deep learning architectures for the prediction of YY1-mediated chromatin loops2023Ingår i: Bioinformatics research and applications: 19th international symposium, ISBRA 2023, Wrocław, Poland, October 9–12, 2023, proceedings / [ed] Xuan Guo; Serghei Mangul; Murray Patterson; Alexander Zelikovsky, Springer, 2023, s. 72-84Konferensbidrag (Refereegranskat)
    Abstract [en]

    YY1-mediated chromatin loops play substantial roles in basic biological processes like gene regulation, cell differentiation, and DNA replication. YY1-mediated chromatin loop prediction is important to understand diverse types of biological processes which may lead to the development of new therapeutics for neurological disorders and cancers. Existing deep learning predictors are capable to predict YY1-mediated chromatin loops in two different cell lines however, they showed limited performance for the prediction of YY1-mediated loops in the same cell lines and suffer significant performance deterioration in cross cell line setting. To provide computational predictors capable of performing large-scale analyses of YY1-mediated loop prediction across multiple cell lines, this paper presents two novel deep learning predictors. The two proposed predictors make use of Word2vec, one hot encoding for sequence representation and long short-term memory, and a convolution neural network along with a gradient flow strategy similar to DenseNet architectures. Both of the predictors are evaluated on two different benchmark datasets of two cell lines HCT116 and K562. Overall the proposed predictors outperform existing DEEPYY1 predictor with an average maximum margin of 4.65%, 7.45% in terms of AUROC, and accuracy, across both of the datases over the independent test sets and 5.1%, 3.2% over 5-fold validation. In terms of cross-cell evaluation, the proposed predictors boast maximum performance enhancements of up to 9.5% and 27.1% in terms of AUROC over HCT116 and K562 datasets.

  • 2.
    Abdelraouf, Hussein
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    LARGE LANGUAGE MODELS ADAPTED TO SWEDISH OF THE 1920S2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Large Language Models typically perform best when there is a lot of data to train on. An interesting question is how such models perform in less dominant languages (e.g., Swedish) and over domains of historical interest where less modern words and phrasings are used. Specifically, how can existing language models for current usage be adapted to get the best question-answering results when applied over such historical domains? In this Master's thesis, we will use domain adaption on three different pre-trained Swedish NLP language models: BERT base Swedish Cased SQuAD Experimental, GPT-SW3, and IBM Watson. We will fine-tune these models on the specific domain of Vasaloppet's 100-year-old articles to evaluate if the models will have difficulties predicting results from a Swedish source that is a century old. We will evaluate how well these models perform on question answering and report results and lessons learned. 

  • 3.
    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.

  • 4.
    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%.

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  • 5.
    Abrahamsson, Johan
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Informatik.
    Sjöberg, Robin
    Umeå universitet, Samhällsvetenskaplig fakultet, Informatik.
    E-tjänstutveckling ur ett medborgarperspektiv: Att skapa beslutsunderlag baserat på medborgarärendens lämplighet för olika kommunikationskanaler2009Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Citizens’ interaction with governments is an area with unique implications for channel management. Governments need to take the citizens perspective into further consideration in order to be successful in delivering high-quality e-services. This paper aims to determine if a categorization of citizen-initiated contacts from a citizen-centric perspective can be a valuable basis for decisions regarding e-service development. The study consisted of three steps. The first step was an examination of the existing related literature, which resulted in the uncovering of the most important aspects of citizens channel choice. The second step consisted of an elaboration of a classification based on perceived task characteristics and a subsequent matching of the categories to desirable channel characteristics. The third and final step consisted of an application of the proposed categorization on a content management system containing all citizen-initiated contacts in a Swedish municipality. The application indicated that the proposed categorization could possibly be used to guide investments in e-services towards a channel-appropriate direction.

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  • 6.
    Adewole, Kayode S.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Computer Science, University of Ilorin, Ilorin, Nigeria.
    Torra, Vicenç
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    DFTMicroagg: a dual-level anonymization algorithm for smart grid data2022Ingår i: International Journal of Information Security, ISSN 1615-5262, E-ISSN 1615-5270, Vol. 21, s. 1299-1321Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The introduction of advanced metering infrastructure (AMI) smart meters has given rise to fine-grained electricity usage data at different levels of time granularity. AMI collects high-frequency daily energy consumption data that enables utility companies and data aggregators to perform a rich set of grid operations such as demand response, grid monitoring, load forecasting and many more. However, the privacy concerns associated with daily energy consumption data has been raised. Existing studies on data anonymization for smart grid data focused on the direct application of perturbation algorithms, such as microaggregation, to protect the privacy of consumers. In this paper, we empirically show that reliance on microaggregation alone is not sufficient to protect smart grid data. Therefore, we propose DFTMicroagg algorithm that provides a dual level of perturbation to improve privacy. The algorithm leverages the benefits of discrete Fourier transform (DFT) and microaggregation to provide additional layer of protection. We evaluated our algorithm on two publicly available smart grid datasets with millions of smart meters readings. Experimental results based on clustering analysis using k-Means, classification via k-nearest neighbor (kNN) algorithm and mean hourly energy consumption forecast using Seasonal Auto-Regressive Integrated Moving Average with eXogenous (SARIMAX) factors model further proved the applicability of the proposed method. Our approach provides utility companies with more flexibility to control the level of protection for their published energy data.

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  • 7.
    Adewole, Kayode S.
    et al.
    Department of Computer Science and Media Technology, Malmö University, Sweden; Department of Computer Science, University of Ilorin, Ilorin, Nigeria.
    Torra, Vicenç
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Energy disaggregation risk resilience through microaggregation and discrete Fourier transform2024Ingår i: Information Sciences, ISSN 0020-0255, E-ISSN 1872-6291, Vol. 662, artikel-id 120211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Progress in the field of Non-Intrusive Load Monitoring (NILM) has been attributed to the rise in the application of artificial intelligence. Nevertheless, the ability of energy disaggregation algorithms to disaggregate different appliance signatures from aggregated smart grid data poses some privacy issues. This paper introduces a new notion of disclosure risk termed energy disaggregation risk. The performance of Sequence-to-Sequence (Seq2Seq) NILM deep learning algorithm along with three activation extraction methods are studied using two publicly available datasets. To understand the extent of disclosure, we study three inference attacks on aggregated data. The results show that Variance Sensitive Thresholding (VST) event detection method outperformed the other two methods in revealing households' lifestyles based on the signature of the appliances. To reduce energy disaggregation risk, we investigate the performance of two privacy-preserving mechanisms based on microaggregation and Discrete Fourier Transform (DFT). Empirically, for the first scenario of inference attack on UK-DALE, VST produces disaggregation risks of 99%, 100%, 89% and 99% for fridge, dish washer, microwave, and kettle respectively. For washing machine, Activation Time Extraction (ATE) method produces a disaggregation risk of 87%. We obtain similar results for other inference attack scenarios and the risk reduces using the two privacy-protection mechanisms.

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  • 8.
    Adewole, Kayode Sakariyah
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Computer Science, University of Ilorin, Ilorin, Nigeria.
    Torra, Vicenç
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Privacy issues in smart grid data: from energy disaggregation to disclosure risk2022Ingår i: Database and expert systems applications: 33rd international conference, DEXA 2022, Vienna, Austria, August 22–24, 2022, proceedings, part I / [ed] Christine Strauss; Alfredo Cuzzocrea; Gabriele Kotsis; A Min Tjoa; Ismail Khalil, Springer, 2022, s. 71-84Konferensbidrag (Refereegranskat)
    Abstract [en]

    The advancement in artificial intelligence (AI) techniques has given rise to the success rate recorded in the field of Non-Intrusive Load Monitoring (NILM). The development of robust AI and machine learning algorithms based on deep learning architecture has enabled accurate extraction of individual appliance load signature from aggregated energy data. However, the success rate of NILM algorithm in disaggregating individual appliance load signature in smart grid data violates the privacy of the individual household lifestyle. This paper investigates the performance of Sequence-to-Sequence (Seq2Seq) deep learning NILM algorithm in predicting the load signature of appliances. Furthermore, we define a new notion of disclosure risk to understand the risk associated with individual appliances in aggregated signals. Two publicly available energy disaggregation datasets have been considered. We simulate three inference attack scenarios to better ascertain the risk of publishing raw energy data. In addition, we investigate three activation extraction methods for appliance event detection. The results show that the disclosure risk associated with releasing smart grid data in their original form is on the high side. Therefore, future privacy protection mechanisms should devise efficient methods to reduce this risk.

  • 9.
    Adewole, Kayode Sakariyah
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Computer Science and Media Technology, Malmö University, Malmö, Sweden; Department of Computer Science, University of Ilorin, Ilorin, Nigeria.
    Torra, Vicenç
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Computer Science and Media Technology, Malmö University, Malmö, Sweden.
    Privacy protection of synthetic smart grid data simulated via generative adversarial networks2023Ingår i: Proceedings of the 20th international conference on security and cryptography, SECRYPT 2023 / [ed] DiVimercati, SD; Samarati, P, SciTePress, 2023, s. 279-286Konferensbidrag (Refereegranskat)
    Abstract [en]

    The development in smart meter technology has made grid operations more efficient based on fine-grained electricity usage data generated at different levels of time granularity. Consequently, machine learning algorithms have benefited from these data to produce useful models for important grid operations. Although machine learning algorithms need historical data to improve predictive performance, these data are not readily available for public utilization due to privacy issues. The existing smart grid data simulation frameworks generate grid data with implicit privacy concerns since the data are simulated from a few real energy consumptions that are publicly available. This paper addresses two issues in smart grid. First, it assesses the level of privacy violation with the individual household appliances based on synthetic household aggregate loads consumption. Second, based on the findings, it proposes two privacy-preserving mechanisms to reduce this risk. Three inference attacks are simulated and the results obtained confirm the efficacy of the proposed privacy-preserving mechanisms.

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  • 10.
    Adler, Robert
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för informatik.
    Eriksson, Andreas
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för informatik.
    Visuella Effekter Inom Genrespecifik Musikvideoproduktion2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Today almost every artist has a music video. With today’s technology it has become a lot easier for smaller companies or amateur filmers to produce and distribute their work. But how important is an artist’s music video and where do people find their music these days? Other questions we wanted to answer were if there is a typical way a music video looks like based on its genre. And is it possible to break these stereotypical ways of producing music videos and thereby create a higher level of enjoyment from the viewer? Our main idea of achieving this was by the use of visual effects in a genre, which in our opinion usually don’t showcase these types of effects. The genre we decided to work with was singer/songwriter, which we think is one genre that doesn’t typically use visual effects. To back up our opinions we studied a lot of music videos from different genres to really see what was typical for each of them. Furthermore we made a survey to find answers for our questions about people’s views on the importance of a well-made music video and where they watch and find them. After we had found some of our answers we produced a music video, one with, and one without visual effects. We then showed these to a number of people and asked them questions about their opinions. Based on our results from studying different music videos and the surveys we came up with a conclusion. And we can say that using visual effects in a genre were they typically aren’t used is possible and it can enhance a viewers enjoyment of the music video. Although we also found out that it should be done with moderation and in good relations with the specific genre.

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  • 11.
    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.

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  • 12.
    Adlerborn, Björn
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Högpresterande beräkningscentrum norr (HPC2N).
    Kjelgaard Mikkelsen, Carl Christian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Högpresterande beräkningscentrum norr (HPC2N).
    Karlsson, Lars
    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).
    Towards Highly Parallel and Compute-Bound Computation of Eigenvectors of Matrices in Schur Form2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this paper we discuss the problem of computing eigenvectors for matrices in Schur form using parallel computing. We develop a new parallel algorithm and report on the performance of our MPI based implementation. We have also implemented a new parallel algorithm for scaling during the backsubstitution phase. We have increased the arithmetic intensity by interleaving the compution of several eigenvectors and by merging the backward substitution and the back-transformation of the eigenvector computation.

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  • 13.
    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.

  • 14.
    af Geijerstam, Klas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Online graph based latency estimation of microservice applications in a FAAS environment2021Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Function-as-a-Service (FaaS) is an increasingly common platform for many kinds of applications and services, replacing the need to maintain and setup hardware or virtual machines to host functionality in the cloud. The billing model for FaaS is commonly based on actual usage, which makes the ability to estimate the performance and latency of an application before invoking it valuable. This thesis evaluates if previously defined algorithms for offline latency estimation, can be adapted to work with online data. Performing online estimation of latency potentially enables cheaper estimations, as no extra executions are neccessary, and latency estimation of applications and functions that can not be executed spu- riously. The experiments show that for a set of test applications, the previously defined algorithms can achieve greater than 95% accuracy, and that a non-graph based estimation using exponential moving average can achieve greater than 98% accuracy. 

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  • 15.
    Agnello, Danielle Marie
    et al.
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    Loisel, Quentin Emile Armand
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    An, Qingfan
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering.
    Balaskas, George
    Institute of Informatics and Telecommunications, National Centre of Scientific Research Demokritos, Athens, Greece; Department of Digital Systems, University of Piraeus, Greece.
    Chrifou, Rabab
    Department of Public Health and Primary Care, Ghent University, Ghent, Belgium.
    Dall, Philippa
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    de Boer, Janneke
    Department of Public Health and Primary Care, Ghent University, Ghent, Belgium; Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
    Delfmann, Lea Rahel
    Department of Public Health and Primary Care, Ghent University, Ghent, Belgium; Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
    Giné-Garriga, Maria
    Department of Sport Sciences, Faculty of Psychology Education and Sport Sciences, Blanquerna - Ramon Llull University, Barcelona, Spain; Department of Physical Therapy, Faculty of Health Sciences, Blanquerna - Ramon Llull University, Barcelona, Spain.
    Goh, Kunshan
    Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
    Longworth, Giuliana Raffaella
    Department of Sport Sciences, Faculty of Psychology Education and Sport Sciences, Blanquerna - Ramon Llull University, Barcelona, Spain.
    Messiha, Katrina
    Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
    McCaffrey, Lauren
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    Smith, Niamh
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    Steiner, Artur
    Yunus Centre, Glasgow Caledonian University, Glasgow, United Kingdom.
    Vogelsang, Mira
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
    Chastin, Sebastien
    School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom; Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
    Establishing a Health CASCADE-Curated Open-Access Database to Consolidate Knowledge About Co-Creation: Novel Artificial Intelligence-Assisted Methodology Based on Systematic Reviews2023Ingår i: Journal of Medical Internet Research, E-ISSN 1438-8871, Vol. 25, artikel-id e45059Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    BACKGROUND: Co-creation is an approach that aims to democratize research and bridge the gap between research and practice, but the potential fragmentation of knowledge about co-creation has hindered progress. A comprehensive database of published literature from multidisciplinary sources can address this fragmentation through the integration of diverse perspectives, identification and dissemination of best practices, and increase clarity about co-creation. However, two considerable challenges exist. First, there is uncertainty about co-creation terminology, making it difficult to identify relevant literature. Second, the exponential growth of scientific publications has led to an overwhelming amount of literature that surpasses the human capacity for a comprehensive review. These challenges hinder progress in co-creation research and underscore the need for a novel methodology to consolidate and investigate the literature.

    OBJECTIVE: This study aimed to synthesize knowledge about co-creation across various fields through the development and application of an artificial intelligence (AI)-assisted selection process. The ultimate goal of this database was to provide stakeholders interested in co-creation with relevant literature.

    METHODS: We created a novel methodology for establishing a curated database. To accommodate the variation in terminology, we used a broad definition of co-creation that encompassed the essence of existing definitions. To filter out irrelevant information, an AI-assisted selection process was used. In addition, we conducted bibliometric analyses and quality control procedures to assess content and accuracy. Overall, this approach allowed us to develop a robust and reliable database that serves as a valuable resource for stakeholders interested in co-creation.

    RESULTS: The final version of the database included 13,501 papers, which are indexed in Zenodo and accessible in an open-access downloadable format. The quality assessment revealed that 20.3% (140/688) of the database likely contained irrelevant material, whereas the methodology captured 91% (58/64) of the relevant literature. Participatory and variations of the term co-creation were the most frequent terms in the title and abstracts of included literature. The predominant source journals included health sciences, sustainability, environmental sciences, medical research, and health services research.

    CONCLUSIONS: This study produced a high-quality, open-access database about co-creation. The study demonstrates that it is possible to perform a systematic review selection process on a fragmented concept using human-AI collaboration. Our unified concept of co-creation includes the co-approaches (co-creation, co-design, and co-production), forms of participatory research, and user involvement. Our analysis of authorship, citations, and source landscape highlights the potential lack of collaboration among co-creation researchers and underscores the need for future investigation into the different research methodologies. The database provides a resource for relevant literature and can support rapid literature reviews about co-creation. It also offers clarity about the current co-creation landscape and helps to address barriers that researchers may face when seeking evidence about co-creation.

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  • 16. Agugiaro, G.
    et al.
    Remondino, F.
    Girardi, G.
    von Schwerin, J.
    Richards-Rissetto, Heather
    Umeå universitet, Humanistiska fakulteten, Humlab.
    De Amicis, R.
    A web-based interactive tool for multi-resolution 3d models of a maya archaeological site2011Ingår i: 4TH ISPRS INTERNATIONAL WORKSHOP 3D-ARCH 2011: 3D VIRTUAL RECONSTRUCTION AND VISUALIZATION OF COMPLEX ARCHITECTURES / [ed] Remondino, F; ElHakim, S, 2011, nr W16, s. 23-30Konferensbidrag (Refereegranskat)
    Abstract [en]

    Continuous technological advances in surveying, computing and digital-content delivery are strongly contributing to a change in the way Cultural Heritage is "perceived": new tools and methodologies for documentation, reconstruction and research are being created to assist not only scholars, but also to reach more potential users (e.g. students and tourists) willing to access more detailed information about art history and archaeology. 3D computer-simulated models, sometimes set in virtual landscapes, offer for example the chance to explore possible hypothetical reconstructions, while on-line GIS resources can help interactive analyses of relationships and change over space and time. While for some research purposes a traditional 2D approach may suffice, this is not the case for more complex analyses concerning spatial and temporal features of architecture, like for example the relationship of architecture and landscape, visibility studies etc. The project aims therefore at creating a tool, called "QueryArch3D" tool, which enables the web-based visualisation and queries of an interactive, multi-resolution 3D model in the framework of Cultural Heritage. More specifically, a complete Maya archaeological site, located in Copan (Honduras), has been chosen as case study to test and demonstrate the platform's capabilities. Much of the site has been surveyed and modelled at different levels of detail (LoD) and the geometric model has been semantically segmented and integrated with attribute data gathered from several external data sources. The paper describes the characteristics of the research work, along with its implementation issues and the initial results of the developed prototype. [GRAPHICS] .

  • 17.
    Ahlgren, Per
    et al.
    Department of Statistics, Uppsala University, Uppsala (Sweden).
    Chen, Yunwei
    Scientometrics & Evaluation Research Center (SERC), Chengdu Library and Information Center of Chinese Academy of Sciences, Chengdu, 610041 (China).
    Colliander, Cristian
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen. Umeå universitet, Umeå universitetsbibliotek (UB).
    Jan van Eck, Nees
    Centre for Science and Technology Studies, Leiden University (The Netherlands).
    Enhancing Direct Citations: A Comparison of Relatedness Measures for Community Detection in a Large Set of PubMed Publications2020Ingår i: Quantitative Science Studies, E-ISSN 2641-3337, Vol. 1, nr 2, s. 1-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this contribution, the effects of enhancing direct citations, with respect to publication-publication relatedness measurement, by indirect citation relations (bibliographic coupling, co-citation, and extended direct citations) and text relations on clustering solution accuracy are analyzed. We include in the study, for comparison reasons, each approach that is involved in the enhancement of direct citations. In total, we investigate the relative performance of seven approaches. For the evaluation of the approaches, we use a methodology proposed by earlier research. However, the used evaluation criterion is based on MeSH, one of the most sophisticated publication-level classification schemes available. We also introduce an approach, based on interpolated accuracy values, by which overall relative clustering solution accuracy can be studied. The results show that the co-citation approach has the worst performance, and that the direct citations approach is outperformed by the other five investigated approaches. The extended direct citations approach has the best performance, followed by an approach in which direct citations are enhanced by the BM25 textual relatedness measure. An approach that combines direct citations with bibliographic coupling and co-citation performs slightly better than the bibliographic coupling approach, which in turn has a better performance than the BM25 approach.

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  • 18.
    Ahlgren, Per
    et al.
    Department of e-Resources, University Library, Stockholm University.
    Colliander, Cristian
    Högskolan i Jönköping, Högskolebiblioteket.
    Document-document similarity approaches and science mapping: experimental comparison of five approaches2009Ingår i: Journal of Informetrics, ISSN 1751-1577, E-ISSN 1875-5879, Vol. 3, nr 1, s. 49-63Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper treats document-document similarity approaches in the context of science mapping. Five approaches, involving nine methods, are compared experimentally. We compare text-based approaches, the citation-based bibliographic coupling approach, and approaches that combine text-based approaches and bibliographic coupling. Forty-three articles, published in the journal Information Retrieval, are used as test documents. We investigate how well the approaches agree with a ground truth subject classification of the test documents, when the complete linkage method is used, and under two types of similarities, first-order and second-order. The results show that it is possible to achieve a very good approximation of the classification by means of automatic grouping of articles. One text-only method and one combination method, under second-order similarities in both cases, give rise to cluster solutions that to a large extent agree with the classification.

  • 19.
    Ahlgren, Per
    et al.
    Department of e-Resources, University Library, Stockholm University.
    Colliander, Cristian
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Persson, Olle
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Field normalized citation rates, field normalized journal impact and Norwegian weights for allocation of university research funds2012Ingår i: Scientometrics, ISSN 0138-9130, E-ISSN 1588-2861, Vol. 92, nr 2, s. 767-780Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We compared three different bibliometric evaluation approaches: two citationbased approaches and one based on manual classification of publishing channels into quality levels. Publication data for two universities was used, and we worked with two levels of analysis: article and department. For the article level, we investigated the predictive power of field normalized citation rates and field normalized journal impact with respect to journal level. The results for the article level show that evaluation of journals based on citation impact correlate rather well with manual classification of journals into quality levels. However, the prediction from field normalized citation rates to journal level was only marginally better than random guessing. At the department level, we studied three different indicators in the context of research fund allocation within universities and the extent to which the three indicators produce different distributions of research funds. It turned out that the three distributions of relative indicator values were very similar, which in turn yields that the corresponding distributions of hypothetical research funds would be very similar.

  • 20.
    Ahlman Bohm, Jacob
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Minimizing initial margin requirements using computational optimization2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Trading contracts with future commitments requires posting a collateral, called initial margin requirement, to cover associated risks. Differences in estimating those risks and varying risk appetites can however lead to identical contracts having different initial margin requirements at different market places. This creates a potential for minimizing those requirements by reallocating contracts.

    The task of minimizing the requirement is identified as a black-box optimization problem with constraints. The aim of this project was to investigate that optimization problem, how it can best be tackled, and comparing different techniques for doing so. Based on the results and obstacles encountered along the way, some guidelines are then outlined to provide assistance for whomever is interested in solving this or similar problems.

    The project consisted both of a literature study to examine existing knowledge within the subject of optimization, and an implementation phase to empirically test how well that knowledge can be put to use in this case. During the latter various algorithms were tested in a number of different scenarios. Focus was put on practical aspects that could be important in a real situation, such as how much they could decrease the initial margin requirement, execution time, and ease of implementation.

    As part of the literature study, three algorithms were found which were evaluated further: simulated annealing, differential evolution, and particle swarm optimization. They all work without prior knowledge of the function to be optimized, and are thus suitable for black-box optimization.

    Results from the implementation part showed largely similar performance between all three algorithms, indicating that other aspects such as ease of implementation or parallelization potential can be more important to consider when choosing which one to use. They were all well able to optimize different portfolios in a number of different cases. However, in more complex situations they required much more time to do so, showing a potential need to speed up the process.

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  • 21.
    Ahlskog, Johanna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Human-Multi-Drone Interaction in Search and Rescue Systems under High Cognitive Workload2024Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Unmanned Aerial Vehicles (UAV), often referred to as drones, have seen increased use in search and rescue (SAR) missions. Traditionally, these missions involve manual control of each drone for aerial surveillance. As UAV autonomy progresses, the next phase in drone technology consists of a shift to autonomous collaborative multi-drone operations, where drones function collectively in swarms. A significant challenge lies in designing user interfaces that can effectively support UAV pilots in their mission without an overload of information from each drone and of their surroundings.

    This thesis evaluates important human factors, such as situational awareness (SA) and cognitive workload, within complex search and rescue scenarios, with the goal of increasing trust in multi-drone systems through the design and testing of various components. Conducting these user studies aims to generate insights for the future design of multi-drone systems.

    Two prototypes were developed with a multi-drone user interface, and simulated a stressful search and rescue mission with high cognitive workload. In the second prototype, a heatmap guided UAV pilots based on the lost person model. The prototypes were tested in a conducted user study with experienced UAV pilots in different SAR organizations across Sweden.

    The results showed variability in SA while monitoring drone swarms, depending on user interface components and SA levels. The prototypes caused significant cognitive workload, slightly reduced in the heatmap-equipped prototype. Furthermore, there was a marginal increase in trust observed in the prototype with the heatmap. Notably, a lack of manual control raised challenges for the majority of participants and many desired features were suggested by participants. These early expert insights can serve as a starting point for future development of multi-drone systems.

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  • 22.
    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.

  • 23.
    Ahmad, Sabtain
    et al.
    Vienna University of Technology, Vienna, Austria.
    Aral, Atakan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. University of Vienna, Vienna, Austria.
    Hierarchical federated transfer learning: a multi-cluster approach on the computing continuum2023Ingår i: 2023 international conference on machine learning and applications (ICMLA), IEEE, 2023, s. 1163-1168Konferensbidrag (Refereegranskat)
    Abstract [en]

    Federated Learning (FL) involves training models over a set of geographically distributed users. We address the problem where a single global model is not enough to meet the needs of geographically distributed heterogeneous clients. This setup captures settings where different groups of users have their own objectives however, users based on geographical location or task similarity, can be grouped together and by inter-cluster knowledge they can leverage the strength in numbers and better generalization in order to perform more efficient FL. We introduce a Hierarchical Multi-Cluster Computing Continuum for Federated Learning Personalization (HC3FL) to cluster similar clients and train one edge model per cluster. HC3FL incorporates federated transfer learning to enhance the performance of edge models by leveraging a global model that captures collective knowledge from all edge models. Furthermore, we introduce dynamic clustering based on task similarity to handle client drift and to dynamically recluster mobile (non-stationary) clients. We evaluate the HC3FL approach through extensive experiments on real-world datasets. The results demonstrate that our approach effectively improves the performance of edge models compared to traditional FL approaches.

  • 24.
    Ahmad, Sabtain
    et al.
    Institute of Information Systems Engineering, Vienna University of Technology, Vienna, Austria.
    Uyanık, Halit
    Department of Computer Engineering, Istanbul Technical University, Istanbul, Turkey.
    Ovatman, Tolga
    Department of Computer Engineering, Istanbul Technical University, Istanbul, Turkey.
    Sandıkkaya, Mehmet Tahir
    Department of Computer Engineering, Istanbul Technical University, Istanbul, Turkey.
    De Maio, Vincenzo
    Institute of Information Systems Engineering, Vienna University of Technology, Vienna, Austria.
    Brandić, Ivona
    Institute of Information Systems Engineering, Vienna University of Technology, Vienna, Austria.
    Aral, Atakan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Sustainable environmental monitoring via energy and information efficient multi-node placement2023Ingår i: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 10, nr 24, s. 22065-22079Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Internet of Things is gaining traction for sensing and monitoring outdoor environments such as water bodies, forests, or agricultural lands. Sustainable deployment of sensors for environmental sampling is a challenging task because of the spatial and temporal variation of the environmental attributes to be monitored, the lack of the infrastructure to power the sensors for uninterrupted monitoring, and the large continuous target environment despite the sparse and limited sampling locations. In this paper, we present an environment monitoring framework that deploys a network of sensors and gateways connected through low-power, long-range networking to perform reliable data collection. The three objectives correspond to the optimization of information quality, communication capacity, and sustainability. Therefore, the proposed environment monitoring framework consists of three main components: (i) to maximize the information collected, we propose an optimal sensor placement method based on QR decomposition that deploys sensors at information- and communication-critical locations; (ii) to facilitate the transfer of big streaming data and alleviate the network bottleneck caused by low bandwidth, we develop a gateway configuration method with the aim to reduce the deployment and communication costs; and (iii) to allow sustainable environmental monitoring, an energy-aware optimization component is introduced. We validate our method by presenting a case study for monitoring the water quality of the Ergene River in Turkey. Detailed experiments subject to real-world data show that the proposed method is both accurate and efficient in monitoring a large environment and catching up with dynamic changes.

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  • 25.
    Ahmetaj, Shqiponja
    et al.
    TU Wien, Vienna, Austria; WU Wien, Vienna, Austria.
    David, Robert
    WU Wien, Vienna, Austria; Semantic Web Company, Vienna, Austria.
    Polleres, Axel
    WU Wien, Vienna, Austria; Complexity Science Hub Vienna, Vienna, Austria.
    Šimkus, Mantas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. TU Wien, Vienna, Austria.
    Repairing SHACL constraint violations using answer set programming2022Ingår i: The Semantic Web –ISWC 2022: 21st International Semantic Web Conference, Virtual Event, October 23–27, 2022 : Proceedings / [ed] Ulrike Sattler; Aidan Hogan; Maria Keet; Valentina Presutti; João Paulo A. Almeida; Hideaki Takeda; Pierre Monnin; Giuseppe Pirrò; Claudia d’Amato, Springer, 2022, s. 375-391Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Shapes Constraint Language (SHACL) is a recent W3C recommendation for validating RDF graphs against shape constraints to be checked on target nodes of the data graph. The standard also describes the notion of validation reports for data graphs that violate given constraints, which aims to provide feedback on how the data graph can be fixed to satisfy the constraints. Since the specification left it open to SHACL processors to define such explanations, a recent work proposed the use of explanations in the style of database repairs, where a repair is a set of additions to or deletions from the data graph so that the resulting graph validates against the constraints. In this paper, we study such repairs for non-recursive SHACL, the largest fragment of SHACL that is fully defined in the specification. We propose an algorithm to compute repairs by encoding the explanation problem – using Answer Set Programming (ASP) – into a logic program, the answer sets of which correspond to (minimal) repairs. We then study a scenario where it is not possible to simultaneously repair all the targets, which may be often the case due to overall unsatisfiability or conflicting constraints. We introduce a relaxed notion of validation, which allows to validate a (maximal) subset of the targets and adapt the ASP translation to take into account this relaxation. Our implementation in Clingo is – to the best of our knowledge – the first implementation of a repair generator for SHACL.

  • 26.
    Ahmetaj, Shqiponja
    et al.
    TU Wien, Austria.
    Löhnert, Bianca
    TU Wien, Austria.
    Ortiz, Magdalena
    TU Wien, Austria.
    Šimkus, Mantas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. TU Wien, Austria.
    Magic Shapes for SHACL Validation2022Ingår i: Proceedings of the VLDB Endowment, E-ISSN 2150-8097, Vol. 15, nr 10, s. 2284-2296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A key prerequisite for the successful adoption of the Shapes Constraint Language (SHACL)—the W3C standardized constraint language for RDF graphs—is the availability of automated tools that efficiently validate targeted constraints (known as shapes graphs) over possibly very large RDF graphs. There are already significant efforts to produce optimized engines for SHACL validation, but they focus on restricted fragments of SHACL. For unrestricted SHACL, that is SHACL with unrestricted recursion and negation, there is no validator beyond a proof-of-concept prototype, and existing techniques are inherently incompatible with the goal-driven approaches being pursued by existing validators. Instead they require a global computation on the entire data graph that is not only computationally very costly, but also brittle, and can easily result in validation failures due to conflicts that are irrelevant to the validation targets. To address these challenges, we present a ‘magic’ transformation— based on Magic Sets as known from Logic Programming—that transforms a SHACL shapes graph S into a new shapes graph S′ whose validation considers only the relevant neighbourhood of the targeted nodes. The new S′ is equivalent to S whenever there are no conflicts between the constraints and the data, and in case the validation of S fails due to conflicts that are irrelevant to the target, S′ may still admit a lazy, target-oriented validation. We implement the algorithm and run preliminary experiments, showing our approach can be a stepping stone towards validators for full SHACL, and that it can significantly improve the performance of the only prototype validator that currently supports full recursion and negation.

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  • 27.
    Ahmetaj, Shqiponja
    et al.
    Technical University of Vienna, Wien, Austria.
    Ortiz, Magdalena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Oudshoorn, Anouk M.
    Technical University of Vienna, Wien, Austria.
    Šimkus, Mantas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Reconciling SHACL and ontologies: semantics and validation via rewriting2023Ingår i: Proceedings of the 36th international workshop on Description Logics (DL 2023) / [ed] Oliver Kutz; Carsten Lutz; Ana Ozaki, CEUR-WS , 2023Konferensbidrag (Refereegranskat)
    Abstract [en]

    This extended abstract summarizes our recent work [1] on SHACL validation in the presence of OWL 2 QL ontologies. To overcome the challenge posed by the non-monotonic behavior of SHACL constraints, we propose a new intuitive validation semantics and a rewriting algorithm that embeds the effects of the ontological axioms into the SHACL constraints. We analyze the complexity of validation in this setting.

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  • 28.
    Ahmetaj, Shqiponja
    et al.
    Tu Wien, Austria.
    Ortiz, Magdalena
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Oudshoorn, Anouk
    Tu Wien, Austria.
    Šimkus, Mantas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Reconciling SHACL and ontologies: semantics and validation via rewriting2023Ingår i: ECAI 2023 / [ed] Kobi Gal; Ann Nowé; Grzegorz J. Nalepa; Roy Fairstein; Roxana Rădulescu, IOS Press, 2023, s. 27-35Konferensbidrag (Refereegranskat)
    Abstract [en]

    OWL and SHACL are two prominent W3C standards for managing RDF graphs, the data model of the Web. They are used for different purposes and make different assumptions about the completeness of data: SHACL is used for expressing integrity constraints on complete data, while OWL allows inferring implicit facts from incomplete data; SHACL reasoners perform validation, while OWL reasoners do logical inference. Integrating these two tasks into one uniform approach is a relevant but challenging problem. The SHACL standard envisions graph validation in combination with OWL entailment, but it does not provide technical guidance on how to realize this. To address this problem, we propose a new intuitive semantics for validating SHACL constraints with OWL 2 QL ontologies based on a suitable notion of the chase. We propose an algorithm that rewrites a set of recursive SHACL constraints (with stratified negation) and an OWL 2 QL ontology into a stand-alone set of SHACL constraints that preserves validation for every input graph, which can in turn be evaluated using an off-the-shelf SHACL validator. We show that validation in this setting is EXPTIME-complete in combined complexity, but only PTIME-complete in data complexity, i.e., if the constraints and the ontology are fixed.

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  • 29. 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.

  • 30.
    Aili, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Using MPI One-Sided Communication for Parallel Sudoku Solving2023Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis investigates the scalability of parallel Sudoku solving using Donald Knuth’s Dancing Links and Algorithm X with two different MPI communication methods: MPI One-Sided Communication and MPI Send-Receive. The study compares the performance of the two communication approaches and finds that MPI One-Sided Communication exhibits better scalability in terms of speedup and efficiency. The research contributes to the understanding of parallel Sudoku solving and provides insights into the suitability of MPI One-Sided Communication for this task. The results highlight the advantages of using MPI One-Sided Communication over MPI Send-Receive, emphasizing its superior performance in parallel Sudoku solving scenarios. This research lays the foundation for future investigations in distributed computing environments and facilitates advancements in parallel Sudoku solving algorithms.

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  • 31.
    Ait-Mlouk, Addi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Jiang, Lili
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    KBot: a Knowledge graph based chatBot for natural language understanding over linked data2020Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 149220-149230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the rapid progress of the semantic web, a huge amount of structured data has become available on the web in the form of knowledge bases (KBs). Making these data accessible and useful for end-users is one of the main objectives of chatbots over linked data. Building a chatbot over linked data raises different challenges, including user queries understanding, multiple knowledge base support, and multilingual aspect. To address these challenges, we first design and develop an architecture to provide an interactive user interface. Secondly, we propose a machine learning approach based on intent classification and natural language understanding to understand user intents and generate SPARQL queries. We especially process a new social network dataset (i.e., myPersonality) and add it to the existing knowledge bases to extend the chatbot capabilities by understanding analytical queries. The system can be extended with a new domain on-demand, flexible, multiple knowledge base, multilingual, and allows intuitive creation and execution of different tasks for an extensive range of topics. Furthermore, evaluation and application cases in the chatbot are provided to show how it facilitates interactive semantic data towards different real application scenarios and showcase the proposed approach for a knowledge graph and data-driven chatbot.

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  • 32.
    Ait-Mlouk, Addi
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Vu, Xuan-Son
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Jiang, Lili
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    WINFRA: A Web-Based Platform for Semantic Data Retrieval and Data Analytics2020Ingår i: Mathematics, E-ISSN 2227-7390, Vol. 8, nr 11, artikel-id 2090Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Given the huge amount of heterogeneous data stored in different locations, it needs to be federated and semantically interconnected for further use. This paper introduces WINFRA, a comprehensive open-access platform for semantic web data and advanced analytics based on natural language processing (NLP) and data mining techniques (e.g., association rules, clustering, classification based on associations). The system is designed to facilitate federated data analysis, knowledge discovery, information retrieval, and new techniques to deal with semantic web and knowledge graph representation. The processing step integrates data from multiple sources virtually by creating virtual databases. Afterwards, the developed RDF Generator is built to generate RDF files for different data sources, together with SPARQL queries, to support semantic data search and knowledge graph representation. Furthermore, some application cases are provided to demonstrate how it facilitates advanced data analytics over semantic data and showcase our proposed approach toward semantic association rules.

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  • 33.
    Akoglu, Canan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen Designhögskolan.
    The relationship between industrial design and interaction design in product development activities2012Ingår i: Human Factors in Computing Systems (CHI) International Conference, Austin, TX, USA, May 5-10, 2012 (on DVD), Association for Computing Machinery (ACM), 2012Konferensbidrag (Refereegranskat)
  • 34.
    Alaa, Halawani
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Haibo, Li
    School of Computer Science & Communication, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Template-based Search: A Tool for Scene Analysis2016Ingår i: 12th IEEE International Colloquium on Signal Processing & its Applications (CSPA): Proceeding, IEEE, 2016, artikel-id 7515772Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a simple and yet effective technique for shape-based scene analysis, in which detection and/or tracking of specific objects or structures in the image is desirable. The idea is based on using predefined binary templates of the structures to be located in the image. The template is matched to contours in a given edge image to locate the designated entity. These templates are allowed to deform in order to deal with variations in the structure's shape and size. Deformation is achieved by dividing the template into segments. The dynamic programming search algorithm is used to accomplish the matching process, achieving very robust results in cluttered and noisy scenes in the applications presented.

  • 35.
    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.

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  • 36.
    Alatalo, André
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för informatik.
    Vallgren, Erik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för informatik.
    Anpassningar till standardisering inom Software Configuration Management: En fallstudie om standardisering inom mjukvarukonfigurationshantering2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Change is inevitable when software is built and deployed. It’s not particularly problematic to manage change if there is just one system. But in a large global IT organization, with several systems and people who develop, problems may arise. If organizations don’t control change, change will control the organization. Software Configuration Management (SCM) is a set of activities to manage change by identifying objects that are likely to change, establishing relationships among them, managing different versions of the objects, controlling the changes imposed and reporting on the changes made. A way to support the work of SCM is to follow standards. A standard can be compared to a type of rule, but also a directive. In this study we examined how a multinational organization applies standards within SCM. We examined the challenges with applying standards. We also examined whether there are deviations from standards, and in such cases why did the deviations arise and what are the following consequences? The study is based on a qualitative case study that employed interviews with developers, IT architects, operations manager and solution leader. The result of this study shows that some of the challenges in applying standards within SCM are: legacy systems, globalization, CMDB and ITSM-related tools (and their processes). The study also shows that standardization within maintenance is complex and that it’s easily breach and forgotten. The study shows that the consequence of this is that the developers must constantly compromise with standards. The result of this compromise is that it’s possible to carry out the business, but the solutions may not meet standards. In this study we concluded that the organization need to direct more attention towards maintenance, and less on new development. 

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  • 37.
    Aldahir, Abdulsalam
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    EVALUATION OF THE PERFORMANCE OF WEBGPU IN A CLUSTER OF WEB-BROWSERS FOR SCIENTIFIC COMPUTING2022Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The development and wide spread of Internet browsers and technologies make them a tool that can be used for many scientific problems. This raises the question of whether Internet browsers, together with WebGPU and WebRTC, can be used to do scalable computing in a distributed cluster. This thesis answers the question by implementing a peer-to-peer cluster and testing it with two problems, Matrix multiplication and Mandelbrot sets generation. The experimental results show that computing embarrassingly parallel problems are scalable with more than 75% efficiency.

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  • 38.
    Alekzandra, Granath
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Filmskapande för nybörjare - steg för steg2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report is about film making, wich parts that are included in film making and things that is good to think of when doing film for the first time. A short movie has been created and from this, this study has been done to figure out if the theory is like the reality. Also the report is based om the book ”How to get started in film making” by Tom Holden and interviews with people working with film.

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  • 39.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Barsotti, Flavia
    Strategy Office, ING Analytics, ING Bank, Amsterdam, Netherlands; Institute for Advanced Study (IAS), University of Amsterdam, Amsterdam, Netherlands.
    Koçer, Rüya Gökhan
    Strategy Office, ING Analytics, ING Bank, Amsterdam, Netherlands.
    Mendez, Julian Alfredo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Ethical implications of fairness interventions: what might be hidden behind engineering choices?2022Ingår i: Ethics and Information Technology, ISSN 1388-1957, E-ISSN 1572-8439, Vol. 24, nr 1, artikel-id 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The importance of fairness in machine learning models is widely acknowledged, and ongoing academic debate revolves around how to determine the appropriate fairness definition, and how to tackle the trade-off between fairness and model performance. In this paper we argue that besides these concerns, there can be ethical implications behind seemingly purely technical choices in fairness interventions in a typical model development pipeline. As an example we show that the technical choice between in-processing and post-processing is not necessarily value-free and may have serious implications in terms of who will be affected by the specific fairness intervention. The paper reveals how assessing the technical choices in terms of their ethical consequences can contribute to the design of fair models and to the related societal discussions.

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  • 40.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Coelho Mollo, Dimitri
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Dahlgren, Adam
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Devinney, Hannah
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Dignum, Virginia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Ericson, Petter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Jonsson, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kampik, Timotheus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. SAP Signavio, Germany.
    Lenaerts, Tom
    Université Libre de Bruxelles, Belgium; University of California, Berkeley, USA.
    Mendez, Julian Alfredo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Nieves, Juan Carlos
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    ACROCPoLis: a descriptive framework for making sense of fairness2023Ingår i: FAccT '23: Proceedings of the 2023 ACM conference on fairness, accountability, and transparency, ACM Digital Library, 2023, s. 1014-1025Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fairness is central to the ethical and responsible development and use of AI systems, with a large number of frameworks and formal notions of algorithmic fairness being available. However, many of the fairness solutions proposed revolve around technical considerations and not the needs of and consequences for the most impacted communities. We therefore want to take the focus away from definitions and allow for the inclusion of societal and relational aspects to represent how the effects of AI systems impact and are experienced by individuals and social groups. In this paper, we do this by means of proposing the ACROCPoLis framework to represent allocation processes with a modeling emphasis on fairness aspects. The framework provides a shared vocabulary in which the factors relevant to fairness assessments for different situations and procedures are made explicit, as well as their interrelationships. This enables us to compare analogous situations, to highlight the differences in dissimilar situations, and to capture differing interpretations of the same situation by different stakeholders.

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  • 41.
    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 Values2019Ingår i: AISafety 2019: Proceedings of the Workshop on Artificial Intelligence Safety 2019co-located with the 28th International Joint Conference on Artificial Intelligence (IJCAI-19) / [ed] Huáscar Espinoza, Han Yu, Xiaowei Huang, Freddy Lecue, Cynthia Chen, José Hernández-Orallo, Seán Ó hÉigeartaigh, Richard Mallah, CEUR-WS , 2019Konferensbidrag (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.

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  • 42.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Mora-Cantallops, Marçal
    Dpto. Ciencias de la Computación, Universidad de Alcalá, Madrid, Alcalá de Henares, Spain.
    Nieves, Juan Carlos
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    How to teach responsible AI in Higher Education: challenges and opportunities2024Ingår i: Ethics and Information Technology, ISSN 1388-1957, E-ISSN 1572-8439, Vol. 26, nr 1, artikel-id 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent years, the European Union has advanced towards responsible and sustainable Artificial Intelligence (AI) research, development and innovation. While the Ethics Guidelines for Trustworthy AI released in 2019 and the AI Act in 2021 set the starting point for a European Ethical AI, there are still several challenges to translate such advances into the public debate, education and practical learning. This paper contributes towards closing this gap by reviewing the approaches that can be found in the existing literature and by interviewing 11 experts across five countries to help define educational strategies, competencies and resources needed for the successful implementation of Trustworthy AI in Higher Education (HE) and to reach students from all disciplines. The findings are presented in the form of recommendations both for educators and policy incentives, translating the guidelines into HE teaching and practice, so that the next generation of young people can contribute to an ethical, safe and cutting-edge AI made in Europe.

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  • 43.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Theodorou, Andreas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Dignum, Frank
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Dignum, Virginia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Governance by glass-box: implementing transparent moral bounds for AI behaviour2019Ingår i: Proceedings of the 28th International Joint Conference on Artificial Intelligence, 2019, s. 5787-5793Konferensbidrag (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.

  • 44.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Theodorou, Andreas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Dignum, Virginia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Michael, Loizos
    Contestable Black Boxes2020Ingår i: Rules and Reasoning. RuleML+RR 2020. / [ed] V. Gutiérrez-Basulto, T. Kliegr, A. Soylu, M. Giese, D. Roman, Springer, 2020, s. 159-167Konferensbidrag (Refereegranskat)
    Abstract [en]

    The right to contest a decision with consequences on individuals or the society is a well-established democratic right. Despite this right also being explicitly included in GDPR in reference to automated decision-making, its study seems to have received much less attention in the AI literature compared, for example, to the right for explanation. This paper investigates the type of assurances that are needed in the contesting process when algorithmic black boxes are involved, opening new questions about the interplay of contestability and explainability. We argue that specialised complementary methodologies to evaluate automated decision-making in the case of a particular decision being contested need to be developed. Further, we propose a combination of well-established software engineering and rule-based approaches as a possible socio-technical solution to the issue of contestability, one of the new democratic challenges posed by the automation of decision making.

  • 45.
    Aler Tubella, Andrea
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Theodorou, Andreas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Nieves, Juan Carlos
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Interrogating the black box: Transparency through information-seeking dialogues2021Ingår i: Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS, International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) , 2021, s. 106-114Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper is preoccupied with the following question: given a (possibly opaque) learning system, how can we understand whether its behaviour adheres to governance constraints? The answer can be quite simple: we just need to “ask” the system about it. We propose to construct an investigator agent to query a learning agent- the suspect agent- to investigate its adherence to a given ethical policy in the context of an information-seeking dialogue, modeled in formal argumentation settings. This formal dialogue framework is the main contribution of this paper. Through it, we break down compliance checking mechanisms into three modular components, each of which can be tailored to various needs in a vast amount of ways: an investigator agent, a suspect agent, and an acceptance protocol determining whether the responses of the suspect agent comply with the policy. This acceptance protocol presents a fundamentally different approach to aggregation: rather than using quantitative methods to deal with the non-determinism of a learning system, we leverage the use of argumentation semantics to investigate the notion of properties holding consistently. Overall, we argue that the introduced formal dialogue framework opens many avenues both in the area of compliance checking and in the analysis of properties of opaque systems.

  • 46.
    Alexander, Bodén
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Kommunikation och marknadsföring inom Sociala medier – Novamedia Svenska PostkodLotteriet AB2015Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    When I worked with the daily communication with the lottery’s customers on social media the Communications Department at Nova Media Swedish Postcode Lottery contacted me to write a document, plan and present an advertising campaign in their social media channels to Christmas 2014. The company had ideas on a campaign that they wanted develop where my job was to develop and present a plan for how to implement the campaign. The purpose is to explain what PostkodTomten is and to highlight its commercial advantages for marketing purposes. To have succeeded with this work, I needed a clear methodology and plan. I deepened my knowledge in marketing with a clear focus on social media, literary studies has been key and theoretical studies have been a good basis to implement my work practically. The conclusion I take with me in the future, the importance of how to dispose of your work, meetings booked weekly and milestones were set up giving the project good order and structure. This report will first and foremost focus and process these documents but also contains a theoretical part of marketing and communications in social media in general. The document and the report were presented to the company as an appendix. The theoretical parts of the report focuses on the marketing and communications in social media, how it is going to and how to do it appropriately. It is also up to what a company can do to strategically "stick out" and promote themselves on social media and its various channels. The terms "Buzz marketing" and "viral marketing" will also be explained.

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  • 47.
    Algers, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Stereo Camera Calibration Accuracy in Real-time Car Angles Estimation for Vision Driver Assistance and Autonomous Driving2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Bilsäkerhetsföretaget Veoneer är utvecklare av avancerade kamerasystem inom förarassistans, men kunskapen om den absoluta noggrannheten i deras dynamiska kalibreringsalgoritmer som skattar fordonets orientering är begränsad.

    I denna avhandling utvecklas och testas ett nytt mätsystem för att samla in referensdata av ett fordons orientering när det är i rörelse, mer specifikt dess pitchvinkel och rollvinkel. Fokus har legat på att skatta hur osäkerheten i mätsystemet påverkas av fel som introducerats vid dess konstruktion, samt att utreda dess potential när det kommer till att vara ett gångbart alternativ för att samla in referensdata för evaluering av prestandan hos algoritmerna.

    Systemet bestod av tre laseravståndssensorer monterade på fordonets kaross. En rad mätförsök utfördes med olika störningar introducerade genom att köra längs en vägsträcka i Linköping med vikter lastade i fordonet. Det insamlade referensdatat jämfördes med data från kamerasystemet där bias hos de framräknade vinklarna skattades, samt att de dynamiska egenskaperna kamerasystemets algoritmer utvärderades. Resultaten från mätförsöken visade på att noggrannheten i mätsystemet översteg 0.1 grader för både pitchvinklarna och rollvinklarna, men några slutsatser kring eventuell bias hos algoritmerna kunde ej dras då systematiska fel uppstått i mätresultaten.

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  • 48.
    Ali, Hazrat
    et al.
    College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar.
    Shah, Zubair
    College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar.
    Alam, Tanvir
    College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar.
    Wijayatunga, Priyantha
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Elyan, Eyad
    School of Computing Science and Digital Media, Robert Gordon University, Aberdeen, United Kingdom.
    Editorial: recent advances in multimodal artificial intelligence for disease diagnosis, prognosis, and prevention2024Ingår i: Frontiers in Radiology, ISSN 2673-8740, Vol. 3, artikel-id 1349830Artikel i tidskrift (Övrigt vetenskapligt)
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    fulltext
  • 49.
    Ali, Hazrat
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Umander, Johannes
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Rohlén, Robin
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Grönlund, Christer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    A Deep Learning Pipeline for Identification of Motor Units in Musculoskeletal Ultrasound2020Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 170595-170608Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Skeletal muscles are functionally regulated by populations of so-called motor units (MUs). An MU comprises a bundle of muscle fibers controlled by a neuron from the spinal cord. Current methods to diagnose neuromuscular diseases and monitor rehabilitation, and study sports sciences rely on recording and analyzing the bio-electric activity of the MUs. However, these methods provide information from a limited part of a muscle. Ultrasound imaging provides information from a large part of the muscle. It has recently been shown that ultrafast ultrasound imaging can be used to record and analyze the mechanical response of individual MUs using blind source separation. In this work, we present an alternative method - a deep learning pipeline - to identify active MUs in ultrasound image sequences, including segmentation of their territories and signal estimation of their mechanical responses (twitch train). We train and evaluate the model using simulated data mimicking the complex activation pattern of tens of activated MUs with overlapping territories and partially synchronized activation patterns. Using a slow fusion approach (based on 3D CNNs), we transform the spatiotemporal image sequence data to 2D representations and apply a deep neural network architecture for segmentation. Next, we employ a second deep neural network architecture for signal estimation. The results show that the proposed pipeline can effectively identify individual MUs, estimate their territories, and estimate their twitch train signal at low contraction forces. The framework can retain spatio-temporal consistencies and information of the mechanical response of MU activity even when the ultrasound image sequences are transformed into a 2D representation for compatibility with more traditional computer vision and image processing techniques. The proposed pipeline is potentially useful to identify simultaneously active MUs in whole muscles in ultrasound image sequences of voluntary skeletal muscle contractions at low force levels.

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  • 50.
    Ali, Hazrat
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Department of Electrical and Computer Engineering, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, Pakistan.
    Umander, Johannes
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Rohlén, Robin
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Röhrle, Oliver
    Stuttgart Center for Simulation Technology (SC SimTech), University of Stuttgart, Stuttgart, Germany; Institute for Modelling and Simulation of Biomechanical Systems, Chair for Computational Biophysics and Biorobotics, University of Stuttgart, Stuttgart, Germany.
    Grönlund, Christer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Modelling intra-muscular contraction dynamics using in silico to in vivo domain translation2022Ingår i: Biomedical engineering online, E-ISSN 1475-925X, Vol. 21, nr 1, artikel-id 46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Advances in sports medicine, rehabilitation applications and diagnostics of neuromuscular disorders are based on the analysis of skeletal muscle contractions. Recently, medical imaging techniques have transformed the study of muscle contractions, by allowing identifcation of individual motor units’ activity, within the whole studied muscle. However, appropriate image-based simulation models, which would assist the continued development of these new imaging methods are missing. This is mainly due to a lack of models that describe the complex interaction between tissues within a muscle and its surroundings, e.g., muscle fbres, fascia, vasculature, bone, skin, and subcutaneous fat. Herein, we propose a new approach to overcome this limitation.

    Methods: In this work, we propose to use deep learning to model the authentic intramuscular skeletal muscle contraction pattern using domain-to-domain translation between in silico (simulated) and in vivo (experimental) image sequences of skeletal muscle contraction dynamics. For this purpose, the 3D cycle generative adversarial network (cycleGAN) models were evaluated on several hyperparameter settings and modifcations. The results show that there were large diferences between the spatial features of in silico and in vivo data, and that a model could be trained to generate authentic spatio-temporal features similar to those obtained from in vivo experimental data. In addition, we used diference maps between input and output of the trained model generator to study the translated characteristics of in vivo data.

    Results: This work provides a model to generate authentic intra-muscular skeletal muscle contraction dynamics that could be used to gain further and much needed physiological and pathological insights and assess and overcome limitations within the newly developed research feld of neuromuscular imaging.

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