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  • 5551.
    Åhlander, Krister
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Munthe-Kaas, Hans
    Eigenvalues for equivariant matrices2006Inngår i: Journal of Computational and Applied Mathematics, ISSN 0377-0427, E-ISSN 1879-1778, Vol. 192, s. 89-99Artikkel i tidsskrift (Fagfellevurdert)
  • 5552.
    Åhlander, Krister
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Munthe-Kaas, Hans
    On applications of the generalized Fourier transform in numerical linear algebra2004Rapport (Annet vitenskapelig)
  • 5553.
    Åhlander, Krister
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Otto, Kurt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    On software support for finite difference schemes based on index notation2002Inngår i: Computational Science – ICCS 2002, Berlin: Springer-Verlag , 2002, s. 711-718Konferansepaper (Annet vitenskapelig)
  • 5554.
    Åhlander, Krister
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Otto, Kurt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Software design for finite difference schemes based on index notation2006Inngår i: Future generations computer systems, ISSN 0167-739X, E-ISSN 1872-7115, Vol. 22, s. 102-109Artikkel i tidsskrift (Fagfellevurdert)
  • 5555.
    Åhlen, Julia
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Color correction of underwater images based on estimation of diffuse attenuation coefficients2003Inngår i: Proceedings of 3rd conference for the promotion of research in IT, 2003Konferansepaper (Annet vitenskapelig)
  • 5556.
    Åhlfeldt, Rose-Mharie
    et al.
    University of Skövde.
    Huvila, Isto
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för ABM.
    Patient Safety and Patient Privacy When Patient Reading Their Medical Records2014Inngår i: Safe and Secure Cities: 5th International Conference on Well-Being in the Information Society, WIS 2014. Turku, Finland, August 18-20, 2014, Proceedings / [ed] Kaija Saranto and Maaret Castrén and Tiina Kuusela and Sami Hyrynsalmi and Stina Ojala, Heidelberg: Springer, 2014, s. 230-239Konferansepaper (Fagfellevurdert)
    Abstract [en]

    When patients get access to their personal health information new security demands arise. This paper presents results from a study aiming to improve the understanding of how the patients different perceptions of their own personal health and health information preferences can be linked to anticipated positive and negative security concerns. The analysis and discussion focuses on investigating how the security issues and patients perception on the benefits and threats of accessing their medical records relate to each other. The results show that a more holistic systemic perspective to information security is needed to support the effective use of medical records in the healthcare in information and data driven society in order to improve both patient safety and patient privacy.

  • 5557.
    Åhlman, Gustav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik.
    Micro Architecture Independent Data Locality Analysis of Multi Threaded Applications on Multi Core Processors2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In today's computing a significant amount of energy is spent on the movement of data and data related stalls. In order to understand how this energy is spent and can be reduced, we need efficient models of the cache hierarchy. This thesis builds on previous work to create a tool to aid developers in quickly estimating cache behavior of multi-threaded programs on multi-core architectures.

    The tool consists of a profiler that sparsely collects data of a program's memory references and thread interactions, and an analyzer that uses the collected data to estimate cache miss ratios. The tool is able to both model shared and separate caches. For the shared caches a new way of modeling constructive coherence is created.

    Micro-benchmarks and benchmarks from SPLASH-2 and PARSEC benchmark suites are used to validate the functionality of the tool. The tool estimates the miss ratios accurately in most configurations, but is less accurate for small cache sizes. This is consistent with single-threaded studies of the analytical model technique which the tool is based on. The new constructive coherence modeling shows a significant improvement for shared caches, where it detects when threads with shared data-set helps to keeping data inside the cache.

    The performance of the profiler scales well for both the number of threads and size of benchmark, while the analyzer faces scaling difficulties with the number of threads.

  • 5558.
    Åhlén, Julia
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys.
    Colour Correction of Underwater Images Using Spectral Data2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    For marine sciences sometimes there is a need to perform underwater photography. Optical properties of light cause severe quality problems for underwater photography. Light of different energies is absorbed at highly different rates under water causing significant bluishness of the images. If the colour dependent attenuation under water can be properly estimated it should be possible to use computerised image processing to colour correct digital images using Beer’s Law.

    In this thesis we have developed such estimation and correction methods that have become progressively more complicated and more accurate giving successively better correction results. A process of estimation of downwelling attenuation coefficients from multi or hyper spectral data is a basis for automatic colour restoration of underwater taken images. The results indicate that for each diving site the unique and precise coefficients can be obtained.

    All standard digital cameras have built in white balancing and colour enhancement functions designed to make the images as aesthetically pleasing as possible. These functions can in most cameras not be switched off and the algorithms used are proprietary and undocumented. However, these enhancement functions can be estimated. Applying their reverse creates un-enhanced images and we show that our algorithms for underwater colour correction works significantly better when applied to such images.

    Finally, we have developed a method that uses point spectra from the spectrometer together with RGB colour images from a camera to generate pseudo-hyper-spectral images. Each of these can then be colour corrected. Finally, the images can be weighted together in the proportions needed to create new correct RGB images. This method is somewhat computationally demanding but gives very encouraging results.

    The algorithms and applications presented in this thesis show that automatic colour correction of underwater images can increase the credibility of data taken underwater for marine scientific purposes.

    Delarbeid
    1. Color Correction of Underwater Images Based on Estimation of Diffuse Attenuation Coefficients
    Åpne denne publikasjonen i ny fane eller vindu >>Color Correction of Underwater Images Based on Estimation of Diffuse Attenuation Coefficients
    2003 Inngår i: Proceedings of the PICS 2003: The PICS Conference, An International Technical Conference on The Science and Systems of Digital Photography, including the Fifth International Symposium on Multispectral Color Science, ISSN 0-89208-245-3, s. 325-329Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93762 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25bibliografisk kontrollert
    2. Bottom Reflectance Influence on a Color Correction Algorithm for Underwater Images
    Åpne denne publikasjonen i ny fane eller vindu >>Bottom Reflectance Influence on a Color Correction Algorithm for Underwater Images
    2003 (engelsk)Inngår i: Lecture Notes in Computer Science. Proceedings of the 13th Scandinavian Conference on Image Analysis (SCIA), ISSN 0302-9743, Vol. 2749, s. 922-926Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93763 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    3. Improvement of a Color Correction Algorithm for Underwater Images Through Compensating for Digital Camera Behaviour
    Åpne denne publikasjonen i ny fane eller vindu >>Improvement of a Color Correction Algorithm for Underwater Images Through Compensating for Digital Camera Behaviour
    2004 (engelsk)Inngår i: Proceedings of the Swedish Symposium on Image Analysis, s. 142-145Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93764 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    4. Pre-Processing of Underwater Images Taken in Shallow Water for Color Reconstruction Purposes
    Åpne denne publikasjonen i ny fane eller vindu >>Pre-Processing of Underwater Images Taken in Shallow Water for Color Reconstruction Purposes
    2005 (engelsk)Inngår i: Proceedings of the 7th IASTED International Conference on Signal and Image ProcessingArtikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93765 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    5. Dissolved Organic Matters Impact on Colour Reconstruction in Underwater Images
    Åpne denne publikasjonen i ny fane eller vindu >>Dissolved Organic Matters Impact on Colour Reconstruction in Underwater Images
    2005 (engelsk)Inngår i: Lecture Notes in Computer Science. Proceedings of the 14th Scandinavian Conference on Image Analysis, ISSN 3-540-26320-9, Vol. 3540, s. 1148-1156Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93766 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    6. Evaluation of Underwater Spectral Data for Colour Correction Applications
    Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of Underwater Spectral Data for Colour Correction Applications
    (engelsk)Artikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-93767 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    7. Application of Underwater Spectral Data for Colour Correction Purposes
    Åpne denne publikasjonen i ny fane eller vindu >>Application of Underwater Spectral Data for Colour Correction Purposes
    (engelsk)Artikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-93768 (URN)
    Tilgjengelig fra: 2005-11-25 Laget: 2005-11-25 Sist oppdatert: 2010-03-01bibliografisk kontrollert
    Fulltekst (pdf)
    FULLTEXT01
    Download (pdf)
    COVER01
  • 5559. Åhlén, Julia
    et al.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Automatic Water Body Extraction From Remote Sensing Images Using Entropy2015Inngår i: SGEM2015 Conference Proceedings, 2015, Vol. 2, s. 517-524Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This research focuses on automatic extraction of river banks and other inland waters from remote sensing images. There are no up to date accessible databases of rivers and most of other waters objects for modelling purposes. The main reason for that is that some regions are hard to access with the traditional ground through techniques and thus the boundary of river banks are uncertain in many geographical positions. The other reason is the limitations of widely applied method for extraction of water bodies called normalized-difference water index (NDWI). There is a novel approach to extract water bodies, which is based on pixel level variability or entropy, however, the methods work somewhat satisfactory on high spatial resolution images, there is no verification of the method performance on moderate or low resolution images. Problems encounter identification of mixed water pixels and e.g. roads, which are built in attachment to river banks and thus can be classified as rivers. In this work we propose an automatic extraction of river banks using image entropy, combined with NDWI identification. In this study only moderate spatial resolution Landsat TM are tested. Areas of interest include both major river banks and inland lakes. Calculating entropy on such poor spatial resolution images will lead to misinterpretation of water bodies, which all exhibits the same small variation of pixel values as e.g. some open or urban areas. Image entropy thus is calculated with the modification that involves the incorporation of local normalization index or variability coefficient. NDWI will produce an image where clear water exhibits large difference comparing to other land features. We are presenting an algorithm that uses an NDWI prior to entropy processing, so that bands used to calculate it, are chosen in clear connection to water body features that are clearly discernible.As a result we visualize a clear segmentation of the water bodies from the remote sensing images and verify the coordinates with a given geographic reference.

  • 5560.
    Åhlén, Julia
    et al.
    Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Indication of Methane Gas in IR-Imagery2011Inngår i: Proceedings of IADIS International Conference Computer Graphics, Visualization, Computer Vision and Image Processing 2011 (CGVCVIP 2011), 2011, s. 187-192Konferansepaper (Fagfellevurdert)
  • 5561.
    Åhlén, Julia
    et al.
    Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Knowledge Based Single Building Extraction and Recognition2014Inngår i: Proceedings WSEAS International Conference on Computer Engineering and Applications, 2014, 2014, s. 29-35Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Building facade extraction is the primary step in the recognition process in outdoor scenes. It is also achallenging task since each building can be viewed from different angles or under different lighting conditions. Inoutdoor imagery, regions, such as sky, trees, pavement cause interference for a successful building facade recognition.In this paper we propose a knowledge based approach to automatically segment out the whole facade or majorparts of the facade from outdoor scene. The found building regions are then subjected to recognition process. Thesystem is composed of two modules: segmentation of building facades region module and facade recognition module.In the facade segmentation module, color processing and objects position coordinates are used. In the facaderecognition module, Chamfer metrics are applied. In real time recognition scenario, the image with a building isfirst analyzed in order to extract the facade region, which is then compared to a database with feature descriptors inorder to find a match. The results show that the recognition rate is dependent on a precision of building extractionpart, which in turn, depends on a homogeneity of colors of facades.

  • 5562. Åhlén, Julia
    et al.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Mapping of roof types in orthophotos using feature descriptors2018Inngår i: Proc. International Multidisciplinary Scientific GeoConference: SGEM 2018, 2018, s. 285-291Konferansepaper (Fagfellevurdert)
  • 5563.
    Åhlén, Julia
    et al.
    Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Prediction of Ventilation Paths in Urban Environments using Digitized Maps2009Inngår i: Proceedings of the IADIS International Conference Applied Computing 2009, 2009, s. 217-221Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Urban populations and the density of settlements constantly become higher. This leads to higher energy consumption and generally to deterioration of life comfort. Study of urban heat and cool islands is of great importance for social community planners and building engineers. Ventilation paths are defined by turbulent mass, momentum and energy transport conditions and can thus be modeled. This area is usually studied by measurements of the conditions and air flows in laboratory environments. This paper presents a method for the prediction of free ventilation paths in a small city using digital imagery. A digitized map created from a eographic data base is used as input. Image analysis is performed in order to create an optimal edge image. A modified Hough transform is applied. Points of interest are defined and surroundings are calculated. These points are inputs to a parameter space. As a result a free wind passage is predicted based on the position of the observer. Prediction is done by calculation of possible straight lines in a parameter space. Finally, the method is verified by comparison with position vectors from the same space in the image and the best fitted path is chosen.

  • 5564.
    Åhlén, Julia
    et al.
    Akademi för Teknik och Miljö, Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Segmentation of shadows and water bodies in high resolution images using ancillary data2016Inngår i: Proc. 16th International Multidisciplinary Scientific GeoConference, 2016, Vol. 1, s. 827-834Konferansepaper (Fagfellevurdert)
    Abstract [en]

    High spatial resolution imagery is often affected by shadows, both in urban environments with large variations in surface elevation and in vegetated areas. It is a common bias in classification when waters and shadows are registered as the same area. The radiometric response for the shadowed regions should be restored prior to classification. To enable that, separate classes of non-shadowed regions and shadowed areas should be created. Previous work on water extraction using low/medium resolution images, mainly faced two difficulties. Firstly, it is difficult to obtain accurate position of water boundary and secondly, shadows of elevated objects e.g. buildings, bridges, towers and trees are a typical source of noise when facing water extraction in urban regions. In high resolution images the problem of separation water and shadows becomes more prominent since the small local variation of intensity values gives rise to misclassification. This paper proposes a robust method for separation of shadowed areas and water bodies in high spatial resolution imagery using hierarchical method on different scales combined with classification of PCA (Principal Component Analysis) bands, which reduces the effects of radiometric and spatial differences that is commonly associated with the pixel-based methods for multisource data fusion. The method uses ancillary data to aid in classification of shadows and waters. The proposed method includes three steps: segmentation, classification and postprocessing. To achieve robust segmentation, we apply the merging region with three features (PCA bands, NSVDI (Normalized Saturation-value Difference Index) and height data). NSVDI discriminates shadows and some water. In the second step we use hierarchic region based classification to identify water regions. After that step candidates for water pixels are verified by the LiDAR DEM data. As a last step we consider shape parameters such as compactness and symmetry to completely remove shadows.

  • 5565.
    Åhlén, Julia
    et al.
    Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    TIME-SPACE VISUALISATION OF AMUR RIVER CHANNEL CHANGES DUE TO FLOODING DISASTER2014Inngår i: Proceedings of International Multidisciplinary Scientific GeoScience Conference (SGEM), 2014, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The analysis of flooding levels is a highly complex temporal and spatial assessment task that involves estimation of distances between references in geographical space as well as estimations of instances along the time-line that coincide with given spatial locations. This work has an aim to interactively explore changes of Amur River boundaries caused by the severe flooding in September 2013. In our analysis of river bank changes we use satellite imagery (Landsat 7) to extract parts belonging to Amur River. We use imagery from that covers time interval July 2003 until February 2014. Image data is pre-processed using low level image processing techniques prior to visualization. Pre-processing has a purpose to extract information about the boundaries of the river, and to transform it into a vectorized format, suitable as inputs subsequent visualization. We develop visualization tools to explore the spatial and temporal relationship in the change of river banks. In particular the visualization shall allow for exploring specific geographic locations and their proximity to the river/floods at arbitrary times. We propose a time space visualization that emanates from edge detection, morphological operations and boundary statistics on Landsat 2D imagery in order to extract the borders of Amur River. For the visualization we use the time-spacecube metaphor. It is based on a 3D rectilinear context, where the 2D geographical coordinate system is extended with a time-axis pointing along the 3rd Cartesian axis. Such visualization facilitates analysis of the channel shape of Amur River and thus enabling for a conclusion regarding the defined problem. As a result we demonstrate our time-space visualization for river Amur and using some amount of geographical point data as a reference we suggest an adequate method of interpolation or imputation that can be employed to estimate value at a given location and time.

  • 5566.
    Åhlén, Julia
    et al.
    Högskolan i Gävle.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Liu, Fei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Evaluation of the Automatic methods for Building Extraction2014Inngår i: International Journal of Computers and Communications, ISSN 2074-1294, Vol. 8, s. 171-176Artikkel i tidsskrift (Fagfellevurdert)
  • 5567.
    Åhlén Julia, Sundgren David
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bottom Reflectance Influence on a Color Correction Algorithm for Underwater Images2003Inngår i: 13th Scandinavian Conference, SCIA 2003 Göteborg, Sweden, June 29-July 2, 2003, 2003, s. 922-926Konferansepaper (Fagfellevurdert)
  • 5568.
    Åhlén, Julia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Sundgren, David
    Bengtsson, Ewert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Application of underwater hyperspectral data for color correction purposes2007Inngår i: Pattern Recognition and Image Analysis, ISSN 1054-6618 (Print) 1555-6212 (Online), Vol. 17, nr 1, s. 170-173Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Color correction of underwater images has been considered a difficult task for a number of reasons. Those include severe absorption of the water column, the unpredictable behavior of light under the water surface, limited access to reliable data for correction purposes, and the fact that we are only able to process three spectral channels, which is insufficient for most color correction applications. Here, the authors present a method to estimate a hyperspectral image from an RGB image and pointwise hyperspectral data. This is then used to color correct the hyperspectral underwater image and transform it back into RGB color space.

  • 5569.
    Åhlén, Julia
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Sundgren, David
    KTH.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Pre-Processing of Underwater Images Taken in shallow Water for Color Reconstruction Purposes2005Inngår i: IASTED Proceeding (479): IASTED 7th Conference on Signal and Image Processing - 2005, 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Coral reefs are monitored with different techniques in or der to examine their health. Digital cameras, which pro vide an economically defendable tool for marine scientists to collect underwater data, tend to produce bluish images due to severe absorption of light at longer wavelengths. In this paper we study the possibilities of correcting for this color distortion through image processing. The decrease of red light by depth can be predicted by Beer’s Law. An other parameter that has been taken into account is the image enhancement functions built into the camera. We use a spectrometer and a reflectance standard to obtain the data needed to approximate the joint effect of these func tions. This model is used to pre-process the underwater images taken by digital cameras so that the red, green and blue channels show correct values before the images are subjected to correction for the effects of the water column through application of Beer’s Law. This process is fully automatic and the amount of processed images is limited only by the speed of computer system. Experimental re sults show that the proposed method works well for cor recting images taken at different depths with two different cameras.

  • 5570.
    Åhlén, Julia
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Sundgren, David
    KTH.
    Lindell, Tommy
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Dissolved Organic Matters Impact on Colour2005Inngår i: Image Analysis: 14th Scandinavian Conference, SCIA 2005, 2005, s. 1148-1156Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The natural properties of water column usually affect under-water

    imagery by suppressing high-energy light. In application such as

    color correction of underwater images estimation of water column parameters is crucial. Diffuse attenuation coefficients are estimated and used for further processing of underwater taken data. The coefficients will give information on how fast light of different wavelengths decreases with increasing depth. Based on the exact depth measurements and data from a spectrometer the calculation of downwelling irradiance will be done. Chlorophyll concentration and a yellow substance factor contribute to a great variety of values of attenuation coefficients at different depth. By taking advantage of variations in depth, a method is presented to

    estimate the in uence of dissolved organic matters and chlorophyll on color correction. Attenuation coefficients that depends on concentration of dissolved organic matters in water gives an indication on how well any spectral band is suited for color correction algorithm.

  • 5571.
    Åhman, Henrik
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media.
    Conceptualizing the self: A critical analysis of the self as a discursive trend in Human-Computer Interaction research2017Inngår i: Human Technology, ISSN 1795-6889, E-ISSN 1795-6889, Vol. 13, nr 2, s. 149-179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Human–Computer Interaction (HCI), the human often has been conceptualized as a user. Although this notion has illuminated one aspect of the human–technology relationship, some researchers have argued for the need to explore alternative notions. One such notion becoming increasingly frequent in HCI is the self. In this paper, a study of how the self is described in 88 HCI research publications is presented. Four main aspects of the self are identified: instrumental, communicative, emotional, and playful. These four aspects differ, yet they present the self as stable, coherent, and individual. However, these characteristics have been criticized by several contemporary philosophers. This paper presents arguments from poststructuralist writers as a foundation for advocating the need to develop further these positions within HCI. The theories of Mark C. Taylor, who combines poststructuralism with complexity theory, provide a framework for viewing the self as relational to the extent that interaction becomes an existential process and thus interactive technology constitutes an existential arena.

    Fulltekst (pdf)
    fulltext
  • 5572.
    Åhman, Henrik
    KTH, Medieteknik och interaktionsdesign, MID.
    Interaction as existential practice: An explorative study of Mark C. Taylor’s philosophical project and its potential consequences for Human-Computer Interaction2016Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This thesis discusses the potential consequences of applying the philosophy of Mark C. Taylor to the field of Human-Computer Interaction (HCI).

    The first part of the thesis comprises a study focusing on two discursive trends in contemporary HCI, materiality and the self, and how these discourses describe interaction. Through a qualitative, inductive content analysis of 171 HCI research articles, a number of themes are identified in the literature and, it is argued, construct a dominant perspective of materiality, the self, and interaction. Examples that differ from the dominant discourse are also discussed as alternative perspectives for each of the three focal areas.

    The second part of the thesis comprises an analysis of Mark C. Taylor’s philosophical project which enables a number of philosophical positions on materiality, the self, and interaction to be identified. These positions are suggested to be variations and rereadings of themes found in Friedrich Nietzsche’s philosophy. These variations emerge as Taylor approaches Nietzsche through poststructuralism and complexity theory, and it is argued that the apparent heterogeneity of Taylor’s project can be understood as a more coherent position when interpreted in relation to Nietzsche’s philosophy.

    Based on the findings of the two literature studies, the thesis then discusses the possible consequences for HCI, if Taylor’s philosophy were to be applied as a theoretical framework. The thesis argues that Taylor’s philosophy describes the interaction between humans and computers  as an existential process, which contrasts with the dominant HCI discourse; that this view can be related to and provide a theoretical foundation for the alternative discourses in HCI; and that it can contribute to developing HCI.

  • 5573.
    Åhman, Henrik
    KTH, Medieteknik och interaktionsdesign, MID.
    The aesthetic turn: Exploring the religious dimensions of digital technology2016Inngår i: Approaching Religion, ISSN 1799-3121, E-ISSN 1799-3121, Vol. 6, nr 2, s. 156-163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The arena for developing digital technology has undergone an aesthetic turn, broadening the focus from a functionalist approach producing centralized systems in the 1970s and 1980s to an increased awareness of the aesthetic aspects of the individual user’s interaction with technology in the 1990s and 2000s. Within the academic research fields studying digital technology (e.g. Human-Computer Interaction and Interaction Design) the aesthetic turn has resulted in a shift from a strong emphasis on user behaviour to an increased interest in aesthetic perspectives on the role of the designer, the design process, and the design material. Within these fields, aesthetics has often been interpreted as belonging to the realm of the individual; personal experiences such as pleasure, engagement, and emotions have been emphasized in both technology development and technology research. Aesthetics is not, however, only an individual phenomenon but also has relational and structural components that need to be acknowledged. Structural aspects of aesthetics condition the possibilities for individuals interacting with digital technology. Thus, the tension between individual and relational aspects of aesthetics in digital technology also reflects a tension between freedom and limitation; between change and permanence; between destabilizing and stabilizing forces. Such a broadened understanding of aesthetics offers a model of digital technology that roughly corresponds to Mark C. Taylor’s definition of religion. Taylor argues that religion is constituted by, on the one hand, a figuring moment characterized by structural stability and universality, and, on the other hand, a disfiguring moment characterized by disruption, particularity, and change. The purpose of this paper is to discuss the aesthetic turn and Taylor’s definition of religion to illustrate similarities between the two, suggesting possible religious dimensions of digital technology and how that can inform our understanding of people’s interaction with digital technology.

  • 5574.
    Åhman, Henrik
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media, Människa-datorinteraktion.
    Hedman, Anders
    KTH Royal Institute of Technology.
    Frameworks for studying social media interaction: A discussion on phenomenology and poststructuralism2019Inngår i: Human-Computer Interaction – INTERACT 2019 / [ed] David Lamas, Fernando Loizides, Lennart Nacke, Helen Petrie, Marco Winckler, Panayiotis Zaphiris, Cham, Switzerland, 2019, Vol. 3, s. 701-718Konferansepaper (Fagfellevurdert)
    Abstract [en]

    During the past decade or so, much HCI research has, according to many researchers, become increasingly phenomenologically oriented. Some have gone so far as to argue that HCI is now in a phenomenological paradigm. But how does such a paradigmatic view work for understanding interaction in the ever growing sphere of social media? Prima facie it may look as it would work only well since social media has become increasingly richer in terms of the sheer range of phenomenologically possible user experiences provided by new and emerging interaction technologies. However, through a critical reading of three major phenomenological works in HCI, we argue that phenomenology as traditionally applied in HCI points indirectly to alternative approaches for engaging in much of contemporary social media research due to its associated semiotic and relationally oriented contents. One possible family of approaches for analyzing such content can be found, as we will argue, in poststructuralist theory. We propose an increased engagement with poststructuralist semiotics grounded in Jacques Derrida’s philosophy and exemplify how this could contribute to the study of social media in the context of HCI.

  • 5575.
    Åke, Viberg
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Språkvetenskapliga fakulteten, Institutionen för lingvistik och filologi. Lingvistik.
    •Wordnets, Framenets and Corpus-based Contrastive Lexicology.2007Inngår i: FRAME 2007: Building frame semantics resources for Scandinavian and Baltic languages. NODALIDA 2007, 2007, s. 1-10Konferansepaper (Fagfellevurdert)
  • 5576.
    Åkerblom, Beatrice
    et al.
    Stockholm University.
    Castegren, Elias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Wrigstad, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Parallel Programming With Arrays in Kappa2018Inngår i: 5th ACM SIGPLAN International Workshop on Libraries, Languages and Compilers for Array Programming, 2018Konferansepaper (Fagfellevurdert)
  • 5577.
    Åkerblom, Beatrice
    et al.
    Stockholm Univ, Stockholm, Sweden..
    Wrigstad, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Measuring Polymorphism in Python Programs2015Inngår i: DLS 2015: Proceedings of the 11th Symposium on Dynamic Languages, New York: ACM Press, 2015, s. 114-128Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Following the increased popularity of dynamic languages and their increased use in critical software, there have been many proposals to retrofit static type system to these languages to improve possibilities to catch bugs and improve performance. A key question for any type system is whether the types should be structural, for more expressiveness, or nominal, to carry more meaning for the programmer. For retrofitted type systems, it seems the current trend is using structural types. This paper attempts to answer the question to what extent this extra expressiveness is needed, and how the possible polymorphism in dynamic code is used in practise. We study polymorphism in 36 real-world open source Python programs and approximate to what extent nominal and structural types could be used to type these programs. The study is based on collecting traces from multiple runs of the programs and analysing the polymorphic degrees of targets at more than 7 million call-sites. Our results show that while polymorphism is used in all programs, the programs are to a great extent monomorphic. The polymorphism found is evenly distributed across libraries and program-specific code and occur both during program start-up and normal execution. Most programs contain a few ``megamorphic'' call-sites where receiver types vary widely. The non-monomorphic parts of the programs can to some extent be typed with nominal or structural types, but none of the approaches can type entire programs.

  • 5578. Åkerholm, Mikael
    et al.
    Carlson, Jan
    Fredriksson, Johan
    Hansson, Hans
    Håkansson, John
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Möller, Anders
    Pettersson, Paul
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Tivoli, Massimo
    The SAVE Approach to Component-Based Development of Vehicular Systems2007Inngår i: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 80, nr 5, s. 655-667Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The component-based strategy aims at managing complexity, shortening time-to-market, and reducing maintenance requirements by building systems with existing components. The full potential of this strategy has not yet been demonstrated for embedded software, mainly because of specific requirements in the domain, e.g., those related to timing, dependability, and resource consumption.

    We present SaveCCT – a component technology intended for vehicular systems, show the applicability of SaveCCT in the engineering process, and demonstrate its suitability for vehicular systems in an industrial case-study. Our experiments indicate that SaveCCT provides appropriate expressiveness, resource efficiency, analysis and verification support for component-based development of vehicular software.

  • 5579. Ålund, Anders
    et al.
    Lötstedt, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Sillén, Mattias
    Parallel single grid and multigrid solution of industrial compressible flow problems1997Inngår i: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 26, s. 775-791Artikkel i tidsskrift (Fagfellevurdert)
  • 5580. Ålund, Anders
    et al.
    Lötstedt, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Sillén, Mattias
    Parallel solution of industrial compressible flow problems with static load balancing1997Inngår i: Parallel Computational Fluid Dynamics: Algorithms and Results Using Advanced Computers, Amsterdam, The Netherlands: Elsevier Science , 1997, s. 336-343Konferansepaper (Fagfellevurdert)
  • 5581.
    Åman Pohjola, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datalogi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Bells and Whistles: Advanced language features in psi-calculi2013Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Psi-calculi is a parametric framework for process calculi similar to popular pi-calculus extensions such as the explicit fusion calculus, the applied pi-calculus and the spi calculus. Remarkably, machine-checked proofs of standard algebraic and congruence properties of bisimilarity apply to every instance of the framework.

    The contribution of this licentiate thesis is to significantly extend the applicability and expressiveness of psi-calculi by incorporating several advanced language features into the framework: broadcasts, higher-order communication, generalised pattern matching, sorts and priorities. The extensions present several interesting technical challenges, such as negative premises. The machine-checked proofs for standard results about bisimilarity are generalised to each of these new settings, and the proof scripts are freely available online.

    Delarbeid
    1. Broadcast psi-calculi with an application to wireless protocols
    Åpne denne publikasjonen i ny fane eller vindu >>Broadcast psi-calculi with an application to wireless protocols
    Vise andre…
    2015 (engelsk)Inngår i: Software and Systems Modeling, ISSN 1619-1366, E-ISSN 1619-1374, Vol. 14, nr 1, s. 201-216Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus, with arbitrary data structures and logical assertions for facts about data. In this paper we add primitives for broadcast communication in order to model wireless protocols. The additions preserve the purity of the psi-calculi semantics, and we formally prove the standard congruence and structural properties of bisimilarity. We demonstrate the expressive power of broadcast psi-calculi by modelling the wireless ad-hoc routing protocol LUNAR and verifying a basic reachability property.

    sted, utgiver, år, opplag, sider
    Springer, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-205258 (URN)10.1007/s10270-013-0375-z (DOI)000349026100012 ()
    Prosjekter
    UPMARCProFuN
    Forskningsfinansiär
    Swedish Research Council, 2013-4853
    Tilgjengelig fra: 2013-11-08 Laget: 2013-08-15 Sist oppdatert: 2018-01-11bibliografisk kontrollert
    2. Higher-order psi-calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Higher-order psi-calculi
    2014 (engelsk)Inngår i: Mathematical Structures in Computer Science, ISSN 0960-1295, E-ISSN 1469-8072, Vol. 24, nr 2, artikkel-id e240203Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus; in earlier work we have explored their expressiveness and algebraic theory. In this paper we consider higher-order psi-calculi through a technically surprisingly simple extension of the framework, and show how an arbitrary psi-calculus can be lifted to its higher-order counterpart in a canonical way. We illustrate this with examples and establish an algebraic theory of higher-order psi-calculi. The formal results are obtained by extending our proof repositories in Isabelle/Nominal.

    sted, utgiver, år, opplag, sider
    Cambridge University Press, 2014
    Emneord
    process calculi, psi calculi, isabelle, theorem proving, nominal, higher-order
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-183610 (URN)10.1017/S0960129513000170 (DOI)000343643500003 ()
    Prosjekter
    UPMARCProFuN
    Forskningsfinansiär
    Swedish Foundation for Strategic Research
    Tilgjengelig fra: 2013-06-24 Laget: 2012-10-30 Sist oppdatert: 2018-01-12bibliografisk kontrollert
    3. A Sorted Semantic Framework for Applied Process Calculi (extended abstract)
    Åpne denne publikasjonen i ny fane eller vindu >>A Sorted Semantic Framework for Applied Process Calculi (extended abstract)
    Vise andre…
    2014 (engelsk)Inngår i: Trustworthy Global Computing: TGC 2013, Springer Berlin/Heidelberg, 2014, s. 103-118Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Applied process calculi include advanced programming constructs such as type systems, communication with pattern matching, encryption primitives, concurrent constraints, nondeterminism, process creation, and dynamic connection topologies. Several such formalisms, e.g. the applied pi calculus,  are extensions of the the pi-calculus; a growing number is geared towards particular applications or computational paradigms.

    Our goal is a unified framework to represent different process calculi and notions of computation. To this end, we extend our previous work on psi-calculi with novel abstract patterns and pattern matching, and add sorts to the data term language, giving sufficient criteria for subject reduction to hold. Our framework can accommodate several existing process calculi; the resulting transition systems are isomorphic to the originals up to strong bisimulation. We also demonstrate  different notions of computation on data terms, including cryptographic primitives and a lambda-calculus with erratic choice. Substantial parts of the meta-theory of sorted psi-calculi have been machine-checked using Nominal Isabelle.

    sted, utgiver, år, opplag, sider
    Springer Berlin/Heidelberg, 2014
    Serie
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 8358
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-203382 (URN)10.1007/978-3-319-05119-2_7 (DOI)978-3-319-05118-5 (ISBN)
    Konferanse
    8th International Symposium on Trustworthy Global Computing, August 30-31, 2013, Buenos Aires, Argentina
    Prosjekter
    UPMARCProFuN
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , RIT08­0065
    Tilgjengelig fra: 2014-03-08 Laget: 2013-07-09 Sist oppdatert: 2018-01-11
    4. Negative premises in applied process calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Negative premises in applied process calculi
    Vise andre…
    2013 (engelsk)Rapport (Annet vitenskapelig)
    Serie
    Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2013-014
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-229004 (URN)
    Tilgjengelig fra: 2013-06-20 Laget: 2014-07-25 Sist oppdatert: 2018-01-11bibliografisk kontrollert
    5. Bisimulation up-to techniques for psi-calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Bisimulation up-to techniques for psi-calculi
    2016 (engelsk)Inngår i: Proc. 5th ACM SIGPLAN Conference on Certified Programs and Proofs / [ed] Avigad, J; Chlipala, A, New York: ACM Press, 2016, s. 142-153Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Psi-calculi is a parametric framework for process calculi similar to popular pi-calculus extensions such as the explicit fusion calculus, the applied pi-calculus and the spi calculus. Remarkably, machine-checked proofs of standard algebraic and congruence properties of bisimilarity apply to all calculi within the framework. Bisimulation up-to techniques are methods for reducing the size of relations needed in bisimulation proofs. In this paper, we show how these bisimulation proof methods can be adapted to psi-calculi. We formalise all our definitions and theorems in Nominal Isabelle, and show examples where the use of up to-techniques yields drastically simplified proofs of known results. We also prove new structural laws about the replication operator.

    sted, utgiver, år, opplag, sider
    New York: ACM Press, 2016
    Emneord
    Bisimulation up-to, process calculus, psi-calculi, Isabelle, Nominal Isabelle, nominal logic
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-229008 (URN)10.1145/2854065.2854080 (DOI)000389021600016 ()9781450341271 (ISBN)
    Konferanse
    CPP 2016, January 18–19, Saint Petersburg, FL
    Tilgjengelig fra: 2016-01-18 Laget: 2014-07-25 Sist oppdatert: 2018-01-11bibliografisk kontrollert
    Fulltekst (pdf)
    fulltext
  • 5582.
    Åman Pohjola, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datalogi.
    Culling Concurrency Theory: Reusable and trustworthy meta-theory, proof techniques and separation results2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    As concurrent systems become ever more complex and ever more ubiquitous, the need to understand and verify them grows ever larger. For this we need formal modelling languages that are well understood, with rigorously verified foundations and proof techniques, applicable to a wide variety of concurrent systems.

    Defining modelling languages is easy; there is a stupefying variety of them in the literature. Verifying their foundations and proof techniques, and developing an understanding of their interrelationship with other modelling languages, is difficult, tedious and error-prone. The contributions of this thesis support these tasks in reusable and trustworthy ways, by results that apply to a wide variety of modelling languages, verified to the highest standards of mathematical rigour in an interactive theorem prover.

    To this end, we extend psi-calculi - a family of process calculi with reusable foundations for formal verification - with several new language features. We prove that the bisimulation meta-theory of psi-calculi carries over to these extended settings. This widens the scope of psi-calculi to important application areas, such as cryptography and wireless communication. We develop bisimulation up-to techniques - powerful proof techniques for showing that two processes exhibit the same observable behaviour - that apply to all psi-calculi. By showing how psi-calculi can encode dynamic priorities under very strong quality criteria, we demonstrate that the expressive power is greater than previously thought. Finally, we develop a simple and widely applicable technique for showing that a process calculus adds expressiveness over another, based on little more than whether parallel components may act independently or not. Many separation results, both novel ones and strengthenings of known results from the literature, emerge as special cases of this technique.

    Delarbeid
    1. Broadcast psi-calculi with an application to wireless protocols
    Åpne denne publikasjonen i ny fane eller vindu >>Broadcast psi-calculi with an application to wireless protocols
    Vise andre…
    2015 (engelsk)Inngår i: Software and Systems Modeling, ISSN 1619-1366, E-ISSN 1619-1374, Vol. 14, nr 1, s. 201-216Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus, with arbitrary data structures and logical assertions for facts about data. In this paper we add primitives for broadcast communication in order to model wireless protocols. The additions preserve the purity of the psi-calculi semantics, and we formally prove the standard congruence and structural properties of bisimilarity. We demonstrate the expressive power of broadcast psi-calculi by modelling the wireless ad-hoc routing protocol LUNAR and verifying a basic reachability property.

    sted, utgiver, år, opplag, sider
    Springer, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-205258 (URN)10.1007/s10270-013-0375-z (DOI)000349026100012 ()
    Prosjekter
    UPMARCProFuN
    Forskningsfinansiär
    Swedish Research Council, 2013-4853
    Tilgjengelig fra: 2013-11-08 Laget: 2013-08-15 Sist oppdatert: 2018-01-11bibliografisk kontrollert
    2. Higher-order psi-calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Higher-order psi-calculi
    2014 (engelsk)Inngår i: Mathematical Structures in Computer Science, ISSN 0960-1295, E-ISSN 1469-8072, Vol. 24, nr 2, artikkel-id e240203Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus; in earlier work we have explored their expressiveness and algebraic theory. In this paper we consider higher-order psi-calculi through a technically surprisingly simple extension of the framework, and show how an arbitrary psi-calculus can be lifted to its higher-order counterpart in a canonical way. We illustrate this with examples and establish an algebraic theory of higher-order psi-calculi. The formal results are obtained by extending our proof repositories in Isabelle/Nominal.

    sted, utgiver, år, opplag, sider
    Cambridge University Press, 2014
    Emneord
    process calculi, psi calculi, isabelle, theorem proving, nominal, higher-order
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-183610 (URN)10.1017/S0960129513000170 (DOI)000343643500003 ()
    Prosjekter
    UPMARCProFuN
    Forskningsfinansiär
    Swedish Foundation for Strategic Research
    Tilgjengelig fra: 2013-06-24 Laget: 2012-10-30 Sist oppdatert: 2018-01-12bibliografisk kontrollert
    3. A Sorted Semantic Framework for Applied Process Calculi
    Åpne denne publikasjonen i ny fane eller vindu >>A Sorted Semantic Framework for Applied Process Calculi
    Vise andre…
    2016 (engelsk)Inngår i: Logical Methods in Computer Science, ISSN 1860-5974, E-ISSN 1860-5974, Vol. 12, nr 1, s. 1-49, artikkel-id 8Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Applied process calculi include advanced programming constructs such as type systems, communication with pattern matching, encryption primitives, concurrent constraints, nondeterminism, process creation, and dynamic connection topologies. Several such formalisms, e.g. the applied pi calculus, are extensions of the the pi-calculus; a growing number is geared towards particular applications or computational paradigms.

    Our goal is a unified framework to represent different process calculi and notions of computation. To this end, we extend our previous work on psi-calculi with novel abstract patterns and pattern matching, and add sorts to the data term language, giving sufficient criteria for subject reduction to hold. Our framework can directly represent several existing process calculi; the resulting transition systems are isomorphic to the originals up to strong bisimulation. We also demonstrate different notions of computation on data terms, including cryptographic primitives and a lambda-calculus with erratic choice. Finally, we prove standard congruence and structural properties of bisimulation; the proof has been machine-checked using Nominal Isabelle in the case of a single name sort.

    Emneord
    Expressiveness, Pattern matching, Type systems, Theorem proving, pi-calculus, Nominal sets
    HSV kategori
    Forskningsprogram
    Datavetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-262199 (URN)10.2168/LMCS-12(1:8)2016 (DOI)000374769600004 ()
    Prosjekter
    UPMARC
    Forskningsfinansiär
    Swedish Research Council, 2013-4853
    Tilgjengelig fra: 2016-03-31 Laget: 2015-09-09 Sist oppdatert: 2019-02-25bibliografisk kontrollert
    4. Priorities Without Priorities: Representing Preemption in Psi-Calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Priorities Without Priorities: Representing Preemption in Psi-Calculi
    2014 (engelsk)Inngår i: Proc. 21st International Workshop on Expressiveness in Concurrency, and 11th Workshop on Structural Operational Semantics, 2014, s. 2-15Konferansepaper, Publicerat paper (Fagfellevurdert)
    Serie
    Electronic Proceedings in Theoretical Computer Science, ISSN 2075-2180 ; 160
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-297468 (URN)10.4204/EPTCS.160.2 (DOI)
    Konferanse
    EXPRESS/SOS 2014, September 1st, Rome, Italy
    Tilgjengelig fra: 2014-08-07 Laget: 2016-06-23 Sist oppdatert: 2018-01-10bibliografisk kontrollert
    5. Bisimulation up-to techniques for psi-calculi
    Åpne denne publikasjonen i ny fane eller vindu >>Bisimulation up-to techniques for psi-calculi
    2016 (engelsk)Inngår i: Proc. 5th ACM SIGPLAN Conference on Certified Programs and Proofs / [ed] Avigad, J; Chlipala, A, New York: ACM Press, 2016, s. 142-153Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Psi-calculi is a parametric framework for process calculi similar to popular pi-calculus extensions such as the explicit fusion calculus, the applied pi-calculus and the spi calculus. Remarkably, machine-checked proofs of standard algebraic and congruence properties of bisimilarity apply to all calculi within the framework. Bisimulation up-to techniques are methods for reducing the size of relations needed in bisimulation proofs. In this paper, we show how these bisimulation proof methods can be adapted to psi-calculi. We formalise all our definitions and theorems in Nominal Isabelle, and show examples where the use of up to-techniques yields drastically simplified proofs of known results. We also prove new structural laws about the replication operator.

    sted, utgiver, år, opplag, sider
    New York: ACM Press, 2016
    Emneord
    Bisimulation up-to, process calculus, psi-calculi, Isabelle, Nominal Isabelle, nominal logic
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-229008 (URN)10.1145/2854065.2854080 (DOI)000389021600016 ()9781450341271 (ISBN)
    Konferanse
    CPP 2016, January 18–19, Saint Petersburg, FL
    Tilgjengelig fra: 2016-01-18 Laget: 2014-07-25 Sist oppdatert: 2018-01-11bibliografisk kontrollert
    6. The Expressive Power of Monotonic Parallel Composition
    Åpne denne publikasjonen i ny fane eller vindu >>The Expressive Power of Monotonic Parallel Composition
    2016 (engelsk)Inngår i: Programming Languages and Systems, Berlin: Springer, 2016, s. 780-803Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Berlin: Springer, 2016
    Serie
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 9632
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-297465 (URN)10.1007/978-3-662-49498-1_30 (DOI)000401936100030 ()978-3-662-49497-4 (ISBN)
    Konferanse
    ESOP 2016, April 3–7, Eindhoven, The Netherlands
    Tilgjengelig fra: 2016-03-22 Laget: 2016-06-23 Sist oppdatert: 2018-01-10bibliografisk kontrollert
    Fulltekst (pdf)
    fulltext
    Download (jpg)
    presentationsbild
  • 5583.
    Åman Pohjola, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Borgström, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Parrow, Joachim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Raabjerg, Palle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Rodhe, Ioana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Negative premises in applied process calculi2013Rapport (Annet vitenskapelig)
  • 5584.
    Åman Pohjola, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Parrow, Joachim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Bisimulation up-to techniques for psi-calculi2016Inngår i: Proc. 5th ACM SIGPLAN Conference on Certified Programs and Proofs / [ed] Avigad, J; Chlipala, A, New York: ACM Press, 2016, s. 142-153Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Psi-calculi is a parametric framework for process calculi similar to popular pi-calculus extensions such as the explicit fusion calculus, the applied pi-calculus and the spi calculus. Remarkably, machine-checked proofs of standard algebraic and congruence properties of bisimilarity apply to all calculi within the framework. Bisimulation up-to techniques are methods for reducing the size of relations needed in bisimulation proofs. In this paper, we show how these bisimulation proof methods can be adapted to psi-calculi. We formalise all our definitions and theorems in Nominal Isabelle, and show examples where the use of up to-techniques yields drastically simplified proofs of known results. We also prove new structural laws about the replication operator.

  • 5585.
    Åman Pohjola, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Parrow, Joachim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Priorities Without Priorities: Representing Preemption in Psi-Calculi2014Inngår i: Proc. 21st International Workshop on Expressiveness in Concurrency, and 11th Workshop on Structural Operational Semantics, 2014, s. 2-15Konferansepaper (Fagfellevurdert)
  • 5586.
    Åman Pohjola, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Parrow, Joachim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    The Expressive Power of Monotonic Parallel Composition2016Inngår i: Programming Languages and Systems, Berlin: Springer, 2016, s. 780-803Konferansepaper (Fagfellevurdert)
  • 5587. Ånäs, Sofia
    A comparative validation of the human variant simulator SIMdrom2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The past decade’s progress in next generation sequencing has drastically decreased

    the price of whole genome and exome sequencing, making it available as a clinical tool

    for diagnosing patients with genetic disease. However, finding a disease-causing

    mutation among millions of non-pathogenic variants in a patient’s genome, is not an

    easy task. Therefore, algorithms for finding variants relevant for clinicians to

    investigate more closely are needed and constantly developed. To test these

    algorithms a software called SIMdrom has been developed to simulate test data. In

    this project, the simulated data is validated through comparison to real genetic data to

    ensure that it is suitable to use as test data. Through ensuring the data’s reliability and

    finding possible improvements, the development of algorithms for finding

    disease-causing mutations can be facilitated. This in-turn could lead to better

    diagnosing-possibilities for clinicians. When visualizing simulated data together with

    real genomes using principal components analysis, it clusters near it’s real

    counterpart. This shows that the simulated data resembles the real genomes.

    Simulated exomes also performed well when used as a part in one of three training

    sets for the classifier in the Prioritization of Exome Data by Image Analysis study.

    Here they perform second best after an in-house data set consisting of real exomes.

    To conclude, the SIMdrom simulated data performs well in both parts of this project.

    Additional tests of its validity should include testing against larger real data sets, an

    improvement possibility could be to implement a simulation option for spiking in

    noise.

    Fulltekst (pdf)
    fulltext
  • 5588.
    Åslin, Matilda
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Molekylär medicin. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Brandt, Monika
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Molekylär medicin. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Dahlberg, Johan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Molekylär medicin. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    CheckQC: Quick quality control of Illumina sequencing runs2018Inngår i: The Journal of Open Source Software, ISSN 2475-9066, Vol. 3, nr 22, artikkel-id 556Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 5589. Åsén, Per-Olov
    et al.
    Kreiss, Gunilla
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Numerisk analys.
    Rempfer, Dietmar
    Direct numerical simulations of localized disturbances in pipe Poiseuille flow2010Inngår i: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 39, s. 926-935Artikkel i tidsskrift (Fagfellevurdert)
  • 5590.
    Ó Conchúir, Eoin
    et al.
    University of Limerick.
    Holmström Olsson, Helena
    IT-universitetet i Göteborg.
    Ågerfalk, Pär
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media.
    Fitzgerald, Brian
    Benefits of global software development: Exploring the unexplored2009Inngår i: Software Process: Improvement and Practice, ISSN 1077-4866, E-ISSN 1099-1670, Vol. 14, nr 4, s. 201-212Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organizations are increasingly moving to the global software development (GSD) model because of significant benefits that can accrue. However, GSD is fraught with challenges arising from geographical, temporal and socio-cultural distances. The emphasis in the literature to date has typically been on how to overcome the challenges associated with GSD. While a number of GSD benefits have been widely referred to in the literature, there are also a number of less obvious benefits that can be inferred as potentially accruing from GSD. In this article, we identify the various benefits of GSD, labeling them as ‘referred’ and ‘inferred’, respectively. We provide a categorization in terms of (a) organizational, (b) team and (c) process-task. While the ‘referred’ benefits most often apply at the organizational level (e.g. cost savings, access to large multi-skilled workforces, reduced time to market and proximity to customer), the ‘inferred’ benefits apply to a greater extent at team and process-task level (e.g. task modularization, team autonomy, improved documentation and clearly defined processes). In the decision of whether or not to globalize software development activities, a categorization including both ‘referred’ and ‘inferred’ benefits will be helpful in providing a synthesis of all potential benefits associated with GSD.

  • 5591.
    Öfverstedt, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Stochastic Distance Functions with Applications in Object Detection and Image Segmentation2019Inngår i: Swedish Symposium on Image Analysis, 2019Konferansepaper (Annet vitenskapelig)
  • 5592.
    Öfverstedt, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Stochastic Distance Transform2019Inngår i: Discrete Geometry for Computer Imagery, Springer, 2019, s. 75-86Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The distance transform (DT) and its many variations are ubiquitous tools for image processing and analysis. In many imaging scenarios, the images of interest are corrupted by noise. This has a strong negative impact on the accuracy of the DT, which is highly sensitive to spurious noise points. In this study, we consider images represented as discrete random sets and observe statistics of DT computed on such representations. We, thus, define a stochastic distance transform (SDT), which has an adjustable robustness to noise. Both a stochastic Monte Carlo method and a deterministic method for computing the SDT are proposed and compared. Through a series of empirical tests, we demonstrate that the SDT is effective not only in improving the accuracy of the computed distances in the presence of noise, but also in improving the performance of template matching and watershed segmentation of partially overlapping objects, which are examples of typical applications where DTs are utilized.

  • 5593.
    Öfverstedt, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Normann, Per
    Deterministic parallel graph coloring with repartitioning by auxiliary graph coloring2015Rapport (Annet vitenskapelig)
  • 5594.
    Öfverstedt, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Distance between vector-valued fuzzy sets based on intersection decomposition with applications in object detection2017Inngår i: Mathematical Morphology and its Applications to Signal and Image Processing, Springer, 2017, Vol. 10225, s. 395-407Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present a novel approach to measuring distance between multi-channel images, suitably represented by vector-valued fuzzy sets. We first apply the intersection decomposition transformation, based on fuzzy set operations, to vector-valued fuzzy representations to enable preservation of joint multi-channel properties represented in each pixel of the original image. Distance between two vector-valued fuzzy sets is then expressed as a (weighted) sum of distances between scalar-valued fuzzy components of the transformation. Applications to object detection and classification on multi-channel images and heterogeneous object representations are discussed and evaluated subject to several important performance metrics. It is confirmed that the proposed approach outperforms several alternative single-and multi-channel distance measures between information-rich image/ object representations.

  • 5595.
    Öfverstedt, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Distance Between Vector-valued Images based on Intersection Decomposition with Applications in Object Detection2018Inngår i: Swedish Symposium on Image Analysis, 2018Konferansepaper (Annet vitenskapelig)
  • 5596.
    Öfverstedt, Linn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    Why go headless – a comperative study between traditional CMS and the emerging headless trend2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    There has been an exponential increase in the number of websites, digital channels and consequently digital content in the last years. Not only are the number of websites increasing but they are also becoming more complex, therefore it is no longer feasible to handle content and code with the same tools. Content Management Systems (CMS) are the solution to this problem and offers a way of managing content. The market today offers a broad variety of solutions that each have their own advantages, one of the more common being WYSWYG-functionality which often means that the functionality and the presentation of the content are tightly coupled. "Headless" CMS are a new way of doing things and offers the user a way of managing content without presenting them with a way of displaying the content. The different types of CMS present advantages and disadvantages from a user centred point of view as well as from a technical one. The thesis aims to explore these perspectives and form a hypothesis based on the studied cases. The study presents a set of aspects that based on the context in which the CMS is used and implemented can be perceived as either advantages or disadvantages. "Headless" CMS however shows a tendency to be the preferable choice where the editors have a technical background and the developing part values an agnostic approach when implementing a CMS, whereas a traditional CMS with WYSIWYG functionality tends to be more favourable where stability and editorial freedom are valued.

    Fulltekst (pdf)
    fulltext
  • 5597.
    Öhman Persson, Jenny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för människa-datorinteraktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Människa-datorinteraktion.
    The Obvious & The Essential: Interpreting Software Development & Organizational Change2004Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Examining how our basic values affect development processes is the overall theme of this thesis. In practice, the question is investigated in relation to software development and organizational change and in research, in relation to science and its relationship to common sense, specifically within the area of Human Computer Interaction. The thesis discusses how it might be possible to discover what is essential for development processes and why the essential may be interpreted as something other than the simply obvious. This thesis examines ways of studying and understanding our social environment and development processes, particularly those concerning people, organizations and software. The empirical examples deal with a software development project and a project that scrutinized the strategy for a governmental authority’s business and information technology. Attitudes are discussed in terms of how they view the user, the customer, the software developers, the software, organizational and implementation processes, organizational management, aesthetic values, functionality and use, research, methods, paradigmatic approaches, ethical issues, psychological reactions, sociological prerequisites, categorizations of people and stress-related health consequences. One particular prerequisite for developing superior computer-supported office work has repeatedly presented itself: an open, questioning attitude towards the software development process, towards organizational change and towards the people working in the organizations. A similar attitude towards research and its design can be crucial to the development of new knowledge. This circumstance can be interpreted as an indication of how important it is that we be aware of and question our preconceived notions, in order to develop an autonomous behavior where we take responsibility for our actions. By doing so, we can avoid misinterpretations and not get trapped into making categorizations that are simply obvious. This is essential and must be emphasized in our search for the path to »healthy work«.

    Fulltekst (pdf)
    FULLTEXT01
  • 5598.
    Öhrn, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    General image classifier for fluorescence microscopy using transfer learning2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Modern microscopy and automation technologies enable experiments which can produce millions of images each day. The valuable information is often sparse, and requires clever methods to find useful data. In this thesis a general image classification tool for fluorescence microscopy images was developed usingfeatures extracted from a general Convolutional Neural Network (CNN) trained on natural images. The user selects interesting regions in a microscopy image and then, through an iterative process, using active learning, continually builds a training data set to train a classifier that finds similar regions in other images. The classifier uses conformal prediction to find samples that, if labeled, would most improve the learned model as well as specifying the frequency of errors the classifier commits. The result show that with the appropriate choice of significance one can reach a high confidence in true positive. The active learning approach increased the precision with a downside of finding fewer examples.

    Fulltekst (pdf)
    fulltext
  • 5599.
    Ökvist, Nicklas
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media.
    Furberg, Max
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media.
    Analysmodell för inbyggt dataskydd och dataskydd som standard2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    Analysmodell för inbyggt dataskydd och dataskydd som standard
  • 5600.
    Önell, Annica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Quantifying human balance: Analysis of force plate data1999Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    There is a lack of reliable methods for assessment of balance suited for routine use in clinical settings. The thesis focuses on analysis of force plate data for evaluation of balance during normal, unperturbed standing and sitting. Some commonly used force plate based methods during unperturbed standing are presented.

    Traditional measures, which have been used to quantify the postural sway during standing, were applied to seated children with and without spina bifida. Fundamental differences, that can not be observed visually, were found between the groups. However, the reliability on an individual level was limited since the method could not be used to distinguish between subjects from the two groups.

    It is not only of interest to measure how much the subject sways, but also what movement strategy the subject uses, that is, how he or she sways. A method for analysis of the movement strategy in the sagittal plane during standing is presented and tested. The subject's movements are compared to the movements of an inverted pendulum model. For movement analysis a kinematic measurement system is usually required, while the inverted pendulum method only needs force plate data for the analysis.

    To investigate the relationship between different force plate measures the measures were a) compared to each other and b) compared to a clinical balance test. Results on stroke patients showed that many of the measures quantify different aspects of standing. The standard deviation of the vertical ground reaction force was the only measure that was significantly correlated to the clinical balance test. Measurements on healthy adults and three groups of subjects with reduced or not fully developed balance were analysed to investigate the vertical force further. The healthy adults damped the vertical bodyoscillations caused by the heartbeats more efficiently than the other three groups.

    Finally, it was investigated under what conditions system identification can be used to model the balance system. In contrast to previous studies the model parameters were successfully estimated without any external perturbations and without a kinematic measurement system.

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