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  • 201.
    Abrahamsson, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik.
    Variance Adaptive Quantization and Adaptive Offset Selection in High Efficiency Video Coding2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Video compression uses encoding to reduce the number of bits that are used forrepresenting a video file in order to store and transmit it at a smaller size. Adecoder reconstructs the received data into a representation of the original video.Video coding standards determines how the video compression should beconducted and one of the latest standards is High Efficiency Video Coding (HEVC).One technique that can be used in the encoder is variance adaptive quantizationwhich improves the subjective quality in videos. The technique assigns lowerquantization parameter values to parts of the frame with low variance to increasequality, and vice versa. Another part of the encoder is the sample adaptive offsetfilter, which reduces pixel errors caused by the compression. In this project, thevariance adaptive quantization technique is implemented in the Ericsson researchHEVC encoder c65. Its functionality is verified by subjective evaluation. It isinvestigated if the sample adaptive offset can exploit the adjusted quantizationparameters values when reducing pixel errors to improve compression efficiency. Amodel for this purpose is developed and implemented in c65. Data indicates thatthe model can increase the error reduction in the sample adaptive offset. However,the difference in performance of the model compared to a reference encoder is notsignificant.

  • 202.
    Abrahamsson, Leif R.
    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.
    A priori estimates for solutions of singular perturbations with a turning point1977Inngår i: Studies in applied mathematics (Cambridge), ISSN 0022-2526, E-ISSN 1467-9590, Vol. 56, s. 51-69Artikkel i tidsskrift (Fagfellevurdert)
  • 203.
    Abrahamsson, Leif R.
    et al.
    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.
    Keller, Herbert B.
    Kreiss, Heinz-Otto
    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.
    Difference approximations for singular perturbations of systems of ordinary differential equations1974Inngår i: Numerische Mathematik, ISSN 0029-599X, E-ISSN 0945-3245, Vol. 22, s. 367-391Artikkel i tidsskrift (Fagfellevurdert)
  • 204.
    Abrahamsson, R
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. DEPARTMENT OF SYSTEMS AND CONTROL.
    Larsson, E G
    Li, J
    Habersat, J
    Maksymonko, G
    Bradley, M
    Elimination of leakage and ground-bounce effects in ground-penetrating radar2001Inngår i: Proceedings of the 11th {IEEE} Signal Processing Workshop on Statistical Signal Processing, Orchid Country Club, Singapore, 2001, s. 150-153Konferansepaper (Fagfellevurdert)
  • 205.
    Abrahamsson, R
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. DEPARTMENT OF SYSTEMS AND CONTROL.
    Li, J
    Stoica, P
    Thordarson, G
    Sensitivity of two autofocus algorithms to spatially variant phase error2001Inngår i: Proceedings of the SPIE, Orlando, FL, 2001, Vol. 4382Konferansepaper (Fagfellevurdert)
  • 206.
    Abrahamsson, Richard
    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.
    Estimation Problems in Array Signal Processing, System Identification, and Radar Imagery2006Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This thesis is concerned with parameter estimation, signal processing, and applications.

    In the first part, imaging using radar is considered. More specifically, two methods are presented for estimation and removal of ground-surface reflections in ground penetrating radar which otherwise hinder reliable detection of shallowly buried landmines. Further, a study of two autofocus methods for synthetic aperture radar is presented. In particular, we study their behavior in scenarios where the phase errors leading to cross-range defocusing are of a spatially variant kind.

    In the subsequent part, array signal processing and optimal beamforming is regarded. In particular, the phenomenon of signal cancellation in adaptive beamformers due to array perturbations, signal correlated interferences and limited data for covariance matrix estimation is considered. For the general signal cancellation problem, a class of improved adaptive beamformers is suggested based on ridge-regression. Another set of methods is suggested to mitigate signal cancellation due to correlated signal and interferences based on a novel way of finding a characterization of the interference subspace from observed array data. Further, a new minimum variance beamformer is presented for high resolution non-parametric spatial spectrum estimation in cases where the impinging signals are correlated. Lastly, a multitude of enhanced covariance matrix estimators from the statistical literature are studied as an alternative to other robust adaptive beamforming methods. The methods are also applied to space-time adaptive processing where limited data for covariance matrix estimation is a common problem.

    In the third and final part the estimation of the parameters of a general bilinear problem is considered. The bilinear model is motivated by the application of identifying submarines from their electromagnetic signature and by the identification of a Hamerstein-Wiener model of a non-linear dynamic system. An efficient approximate maximum-likelihood method with closed form solution is suggested for estimating the bilinear model parameters.

  • 207.
    Abrahamsson, Richard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Jacobsson, A
    Stoica, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    A capon-like spatial spectrum estimator for correlated sources2004Inngår i: 12th European Signal Processing Conference: EUSIPCO 2004, 2004Konferansepaper (Fagfellevurdert)
  • 208.
    Abrahamsson, Richard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Kay, Steven M.
    Stoica, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Estimation of the parameters of a bilinear model with applications to submarine detection and system identification2007Inngår i: Digital signal processing (Print), ISSN 1051-2004, E-ISSN 1095-4333, Vol. 17, nr 4, s. 756-773Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work we study the problem of estimating the parameters of a bilinear model describing, e.g., the amplitude modulation of extremely low frequency electromagnetic (ELFE) signatures of submarines. A similar problem arises in estimation of a nonlinear dynamic system using a Hammerstein–Wiener model, where two nonlinear static blocks surround a linear dynamic block. For these purposes a new method is derived. It is also shown in the same context that a two-stage method for parameter estimation of Hammerstein–Wiener models can be interpreted as an approximate least squares method. We also show the similarities with the problem of weighted low-rank approximation and the fact that these problems can be solved exactly in finite time using solvers for global optimization of systems of polynomials based on self dual optimization.

  • 209.
    Abrahamsson, Richard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Selén, Yngve
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Stoica, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Enhanced covariance matrix estimators in adaptive beamforming2007Inngår i: 2007 IEEE International Conference on Acoustics, Speech, and Signal Processing, Vol II, Pts 1-3, 2007, s. 969-972Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper a number of covariance matrix estimators suggested in the literature are compared in terms of their performance in the context of array signal processing. More specifically they are applied in adaptive beamforming which is known to be sensitive to errors in the covariance matrix estimate and where often only a limited amount of data is available for estimation. As many covariance matrix estimators have the form of diagonal loading or eigenvalue adjustments of the sample covariance matrix and as they sometimes offer robustness to array imperfections and finite sample error, they are compared to a recent robustified adaptive Capon beamforming (RCB) method which also has a diagonal loading interpretation. Some of the covariance estimators show a significant improvement over the sample covariance matrix and in some cases they match the performance of the RCB even when a priori knowledge, which is not available in practice, is used for choosing the user parameter of RCB.

  • 210.
    Abrahamsson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Utformning av mjukvarusensorer för avloppsvatten med multivariata analysmetoder2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Varje studie av en verklig process eller ett verkligt system är baserat på mätdata. Förr var den tillgängliga datamängden vid undersökningar ytterst begränsad, men med dagens teknik är mätdata betydligt mer lättillgängligt. Från att tidigare enbart haft få och ofta osammanhängande mätningar för någon enstaka variabel, till att ha många och så gott som kontinuerliga mätningar på ett större antal variabler. Detta förändrar möjligheterna att förstå och beskriva processer avsevärt.

    Multivariat analys används ofta när stora datamängder med många variabler utvärderas. I det här projektet har de multivariata analysmetoderna PCA (principalkomponentanalys) och PLS (partial least squares projection to latent structures) använts på data över avloppsvatten insamlat på Hammarby Sjöstadsverk.

    På reningsverken ställs idag allt hårdare krav från samhället för att de ska minska sin miljöpåverkan. Med bland annat bättre processkunskaper kan systemen övervakas och styras så att resursförbrukningen minskas utan att försämra reningsgraden. Vissa variabler är lätta att mäta direkt i vattnet medan andra kräver mer omfattande laboratorieanalyser. Några parametrar i den senare kategorin som är viktiga för reningsgraden är avloppsvattnets innehåll av fosfor och kväve, vilka bland annat kräver resurser i form av kemikalier till fosforfällning och energi till luftning av det biologiska reningssteget. Halterna av dessa ämnen i inkommande vatten varierar under dygnet och är svåra att övervaka.

    Syftet med den här studien var att undersöka om det är möjligt att utifrån lättmätbara variabler erhålla information om de mer svårmätbara variablerna i avloppsvattnet genom att utnyttja multivariata analysmetoder för att skapa modeller över variablerna. Modellerna kallas ofta för mjukvarusensorer (soft sensors) eftersom de inte utgörs av fysiska sensorer.

    Mätningar på avloppsvattnet i Linje 1 gjordes under tidsperioden 11 – 15 mars 2013 på flera ställen i processen. Därefter skapades flera multivariata modeller för att försöka förklara de svårmätbara variablerna. Resultatet visar att det går att erhålla information om variablerna med PLS-modeller som bygger på mer lättillgänglig data. De framtagna modellerna fungerade bäst för att förklara inkommande kväve, men för att verkligen säkerställa modellernas riktighet bör ytterligare validering ske.

  • 211.
    Abramowicz, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Online recruitment of cutting-edge users: A user experience study of Ericsson Labs developer portal2010Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates how to reach and recruit cutting-edge users to user experience studies. The recruitment of cutting-edge users is difficult since these users usually are not registered in recruitment databases. Cutting-edge users are advanced, early-adopters of technology and sometimes referred to as opinion leaders. Telecom research projects performed at Ericsson Research involve products and services 2-3 years ahead of the market; early-adopters and cutting edge users are therefore an important user group.

     

    To test recruitment methods a user experience study was performed of Ericsson Labs developer portal. Ericsson Labs offers Application Programming Interfaces for mobile and web applications development. Internet marketing theories were used to form a recruitment method. Respondents were recruited from the Ericsson Labs user database and they were contacted individually via email. The users were invited to share their thoughts and ideas about the portal to help improve and possibly influence the direction of the site.

     

    This thesis also assessed different online qualitative research methods applied for user experience research. Online focus groups such as bulletin boards were used to interact with users in addition to individual chat and voice interviews. Performing user experience research on the Internet is a cost-efficient way to interact with users in geographically dispersed areas.

     

    The findings from the study show that recruitment is hard; it is especially difficult to recruit active and conversational respondents from a user database. Providing incentives and using personal communication were shown to be successful strategies to convince users to participate in a study.

  • 212.
    Abrate, Matteo
    et al.
    CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Bacciu, Clara
    CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Hast, Anders
    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. CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Marchetti, Andrea
    CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Minutoli, Salvatore
    CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Tesconi, Maurizio
    CNR Natl Res Council, Inst Informat & Telemat, I-56124 Pisa, Italy.
    Geomemories - A Platform for Visualizing Historical, Environmental and Geospatial Changes of the Italian Landscape2013Inngår i: ISPRS International Journal of Geo-Information. Special issue: Geospatial Monitoring and Modelling of Environmental Change, ISSN 2220-9964, Vol. 2, nr 2, s. 432-455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The GeoMemories project aims at publishing on the Web and digitally preserving historical aerial photographs that are currently stored in physical form within the archives of the Aerofototeca Nazionale in Rome. We describe a system, available at http://www.geomemories.org, that lets users visualize the evolution of the Italian landscape throughout the last century. The Web portal allows comparison of recent satellite imagery with several layers of historical maps, obtained from the aerial photos through a complex workflow that merges them together. We present several case studies carried out in collaboration with geologists, historians and archaeologists, that illustrate the great potential of our system in different research fields. Experiments and advances in image processing technologies are envisaged as a key factor in solving the inherent issue of vast amounts of manual work, from georeferencing to mosaicking to analysis.

  • 213. Abu-Rmileh, Amjad
    et al.
    Garcia-Gabin, Winston
    Zambrano, Darine
    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.
    A robust sliding mode controller with internal model for closed-loop artificial pancreas2010Inngår i: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 48, nr 12, s. 1191-1201Artikkel i tidsskrift (Fagfellevurdert)
  • 214. Abu-Rmileh, Amjad
    et al.
    Garcia-Gabin, Winston
    Zambrano, Darine
    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.
    Internal model sliding mode control approach for glucose regulation in type 1 diabetes2010Inngår i: Biomedical Signal Processing and Control, ISSN 1746-8094, Vol. 5, nr 2, s. 94-102Artikkel i tidsskrift (Fagfellevurdert)
  • 215.
    Acar, Isa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Interaktiv Webb 2.0: Annonseringssystem för www.djurplatsen.se2009Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Web 2.0 represents the next generation of creating interactive applications on the Web. The purpose of this thesis was to develop a service tailored to Web 2.0 technology, where users can post ads for free. The platform is an advertising system specially designed for animals. Surveys and interviews have been done; the result is that today’s advertising services on the Internet are not interactive and user-friendly.

    The users have the possibility to adapt different part of the system to their needs, such as choice of themes. Moreover, the system is prepared to support different languages.

    The paper compares the different server-side languages, databases, and various AJAX-technologies that can be applied in the Web application.

    The developed prototype is functional, but incomplete. It can be found on the Web at www.djurplatsen.se. The buying section is not yet in, and language support is not applied to all pages.

    A survey has been done showing that the result of the developed advertiser system indicates that it is interactive and user-friendly comparing to today’s advertising services.

    On the server side, PHP has been used as the programming language and MySQL as the database.

    The system is tailored to the most popular browsers available on the market so that the system always looks the same regardless of which browser is used.

    The essay concludes with a discussion of the problems encountered during the work especially problems that cropped up with the different browsers.

    Different types of ideas are also mentioned which can be applied in the continued development of the prototype.

  • 216. Aceto, Luca
    et al.
    Longo, GiuseppeVictor, BjörnUppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    The difference between concurrent and sequential computation2003Collection/Antologi (Annet (populærvitenskap, debatt, mm))
  • 217. Aceto, Luca
    et al.
    Victor, BjörnUppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    EXPRESS'00: 7th International Workshop on Expressiveness in Concurrency2000Konferanseproceedings (Annet vitenskapelig)
  • 218.
    Acharya, Rupesh
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Object Oriented Design Pattern Extraction From Java Source Code2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In case of software architecture reconstruction, design pattern detection plays a vital role since its presence reflects the point of design decision. Currently most of the studied approaches only focus on the Gang of Four (GOF) design patterns so those tools are not flexible enough to identify other proprietary pattern instances. Moreover, the GOF design pattern can be implemented in various ways which many of the tools suffers to detect. Apart from that not only design pattern is of vital importance for software architecture reconstruction but other patterns like anti-patterns and presence of bad smell code are also equally important. So the approach discussed here is a solution for detecting any pattern instances (not only GOF patterns) from the source code provided that relevant information is extracted during the static analysis phase.

    Our approach is based on the graph pattern matching technique where the source code is modeled as a graph and the pattern to search for is provided as a graph query pattern. For the detection of patterns we focus on structural and behavioral analysis of source code as in the case of a tool called PINOT. The novelty of our approach compared to PINOT is that the choice of behavioral analyzers can be provided as a constraint in the graph query pattern unlike hardcoded in PINOT. Moreover, we can provide more than one constraint in the graph query pattern at node, edge or complete graph level hence, we can compose our query pattern as we want which helps us to specify different kind of new patterns and handle varying implementations of design patterns as well.

  • 219. Achtzehn, Andreas
    et al.
    Benenson, Zinaida
    Rohner, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Implementing Agreement Protocols in Sensor2006Inngår i: The Second International Workshop on Wireless and Sensor Networks Security (WSNS'06), 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate application of agreement protocols tolerating malicious failures in sensor networks. We identify several scenarios where agreement can be used, and report on our experience with implementing an agreement protocol.

  • 220.
    Achtzehn, Andreas
    et al.
    RWTH Aachen.
    Rohner, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Rodhe, Ioana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    ARPD: Asynchronous random key predistribution in the LEAP framework for Wireless Sensor Networks2007Inngår i: 3rd IEEE International Workshop on Wireless and Sensor Networks Security (IEEE WSNS 2007), 2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the LEAP framework for wireless sensor networks a set of keys is used to secure communication. LEAP distinguishes between unicast (pairwise) communication, group (cluster) communication and global (broadcast) communication. The keys used in pairwise communication are derived from an initial key KI that nodes are equipped with prior to deployment

    and that is deleted after link setup. Further keys are distributed encrypted with these pairwise keys. If the initial key is ever disclosed, the whole network is compromised.

    To lower the threat of KI disclosure, we present a novel KI -less scheme for key predistribution. Our scheme is based on random key redistribution, and proves to perform better in medium sized networks than previous proposals. It is resilient against node capture attacks and allows node to node authentication. Attacks against overlying protocols in the network are more difficult with this scheme.

    We have conducted computations to show the feasibility of our scheme for networks up to a size of 1000 nodes. By introducing a key reuse system we are able to increase the probability of a successful link setup. We have included a security analysis that discusses our scheme’s resistance against commonly known attacks.

  • 221. Acosta, Oscar
    et al.
    Frimmel, Hans
    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, Datoriserad bildanalys.
    Fenster, Aaron
    Ourselin, Sébastien
    Filtering and restoration of structures in 3D ultrasound images2007Inngår i: Proc. 4th International Symposium on Biomedical Imaging, Piscataway, NJ: IEEE , 2007, s. 888-891Konferansepaper (Fagfellevurdert)
  • 222. Acosta, Oscar
    et al.
    Frimmel, Hans
    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, Datoriserad bildanalys.
    Fenster, Aaron
    Salvado, Olivier
    Ourselin, Sébastien
    Pyramidal flux in an anisotropic diffusion scheme for enhancing structures in 3D images2008Inngår i: Medical Imaging 2008: Image Processing, Bellingham, WA, 2008, s. 691429:1-12Konferansepaper (Fagfellevurdert)
  • 223.
    Adamek, Michel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Creating a Graphical User InterfaceTemplate for Izolde: The complete design process, focusing on usability and design2010Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The image analysis company Izolde was in need of a user friendly graphical user interface (GUI) to use as a modifiable template to be able to meet a variety of requests and demands from their clientele.

    This paper describes the process of designing such a GUI with respect to theories within human computer interaction and available usability principles and theories.To familiarise and learn about other software on the market a background research was conducted. Wireframes as well as prototypes were created. With the help of recognised usability inspection tools tests were conducted on users with varied degree of computer experience. Test results were the basis for what would be altered and improved in terms of usability on the prototypes.

    The final result is a flexible user friendly GUI in regards to the criteria outlined by Izolde.

  • 224. Adams, Liz
    et al.
    Daniels, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Goold, Annegret
    Hazzan, Orit
    Lynch, Kathy
    Newman, Ian
    Challenges in teaching capstone courses2003Inngår i: ACM SIGCSE Bulletin, Vol. 35, nr 3, s. 219-220Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many of us run capstone project courses and do so in different ways. The members of this panel come from different countries, belong to different types of institutions, teach in different computing disciplines and the capstone projects they run also vary considerably. Yet, there is a strong sense of consensus about what a capstone project is and how valuable it is as a learning experience for students.The panel discussion will serve as an inspiration to develop new, and change old capstone project courses. The main aim is to discuss why, or why not, different approaches work in a capstone project. What are the learning objectives behind the approach? What are the problems? What are the benefits? How is assessment managed? What resources, tools and techniques are used to administer and manage the projects?Concrete examples of how capstone projects are run at the six institutions represented by the panellists will be given, and issues such as framework, methodologies, project examples and technologies used in the process of producing projects will be addressed.

  • 225. Adams, Robert
    et al.
    Erickson, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Datorteknik.
    Teaching Operating Systems and Networking to Information Systems Majors2000Inngår i: Special Interest Group of Computer Science Eduction (SIGCSE), 2000Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Teaching networking and operating systems to information systems majors presents many challenges. Operating systems and networking tend to be taught in one of two ways. Either the material is non-technical, directed more toward the business information systems major, or the material is overly technical, equivalent of teaching a traditional computer science course. We have developed a model for teaching networking and operating systems to information systems majors that bridges that gap. The material is taught in the context of network administration, a topic well-suited to information systems majors. This paper describes our model, the curriculum we use, and the experience of students and faculty.

  • 226. Adams, Robert
    et al.
    Erickson, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Datorteknik.
    The Role of an Operating Systems Course in the IS Major2001Inngår i: Information Systems Education Conference: (ISECON 2000), 2001Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 227. Adams, Robin
    et al.
    Fincher, Sally
    Pears, Arnold
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Börstler, Jürgen
    Boustedt, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling.
    Dalenius, Peter
    Eken, Gunilla
    Heyer, Tim
    Jacobsson, Andreas
    Lindberg, Vanja
    Molin, Bengt
    Moström, Jan Erik
    Wiggberg, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    What is the word for "Engineering" in Swedish: Swedish students' conceptions of their discipline2007Rapport (Annet vitenskapelig)
  • 228.
    Adamsson, Hampus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    CLASSIFICATION OF ILLEGALADVERTISEMENT: WORKING WITH IMBALANCED CLASSDISTRIBUTIONS USING MACHINE LEARNING2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Interpreting human language entered a new era with the current prevalence of machine learning techniques. The field of natural language processing (NLP) concerns the interaction between human and computer languages. Machine learning is the scientific area involved with the design of algorithms that learn from past experience. These two areas within computer science – NLP and machine learning – enables complex ways of analyzing, and working with written language.

    The goal of this thesis is to implement a prototype that automatically find web-based advertisement related to illicit content. In such scenario, the source material comes mostly in theform of unstructured-, unlabeled-, raw text.

    In order to design a working algorithm in this context, a combination of machine learning and NLP techniques are used. Three machine learning algorithms were used in order to classify material by content: nearest neighbours algorithms, support vectormachines, and multilayer perceptron.

    Two dimensionality reduction techniques were used: principle component analysis and Latent Dirichlet allocation. It should be noted that the latter is more commonly used as method of explaining documents in terms of topic mixtures, rather than reducing dimensionality in a problem.

    NLP representation techniques such as the bag-of-word model andTF/IDF were used. These are essentially different variations of word embedding. The result is evaluated using metrics common ininformation retrieval: precision, recall, F1 measure, and confusionmatrices.

    We found that an important challenge in this context is class imbalance: content of interest is often overshadowed by data representing over-represented classes. Another important challengeis that there are multiple classes, and an accurate labelling of such ontology is often missing. In order to improve the accuracy, more annotated - historical - data is needed.

  • 229.
    Adawi, T
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. DEPARTMENT OF COMPUTER SYSTEMS.
    Berglund, A.
    Booth, S
    Ingerman, Å
    On context in phenomenographic research on understanding heat and temperate2001Inngår i: EARLI Conference, Fribourg, Switzerland, 2001Konferansepaper (Fagfellevurdert)
  • 230. Adawi, Tom
    et al.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Ingerman, Åke
    Booth, Shirley
    On context in phenomenographic research on understanding heat and temperate2002Inngår i: EARLI, Bi-annual Symposium, Fribourg, Switzerland, 2002Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Starting from an empirical study of lay adults' understanding of heatand temperature, we distinguish between different meanings of "context" inphenomenographic research. To confuse the variation in ways of experiencingthe context(s) of the study with the variation in ways of experiencing thephenomenon of study is to risk losing fundamental insights. We discuss contextas experienced and as interwoven with the experience of the phenomenon, andanalyse its significance in two dimensions: (1) the stage of the research project:formulating the question, collecting data, analysing data and deploying results;and (2) "who is experiencing" the context: the individual, the collective, or theresearcher. The arguments are illustrated from the empirical study.

  • 231.
    Adinda, Akram
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Edström, August
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Isaksson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    McLeod, Tyson
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    An online marketplace to help reduce the wastage of Swedish wool2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Over 1800 metric tons of wool is produced in Sweden on a yearly basis, only 300 is used. This project involved creating an online marketplace where wool producers and the general public alike could turn to regarding the purchasing and selling of Swedish wool, as well as general information regarding wool. The goal of this project was to reduce the wastage along with the negative effects it has on the environment, partially by making it easier to buy and sell wool, but also by tackling surrounding problems such as localization and subjectivity when selling. To further understand the wastage, but also wool and its properties, multiple contextual inquiries were conducted alongside a survey. The result is a marketplace, more specifically, a web application, which consists of a section to buy wool and a section to sell wool. Furthermore, the web application also consists of a section with general information regarding Swedish wool and a map showing wool nearby.

  • 232.
    Adinugroho, Sigit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Calving Events Detection and Quantification from Time-lapse Images: A Case Study of Tunabreen Glacier, Svalbard2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A fully automated method for detecting and measuring calving regions of a glacier is an important tool to gather massive statistical data of calving events. A new framework to achieve the goals is presented in this thesis. First, time-lapse images are registered to the first image in the set. Registration process makes use of the M-Estimator Sample Consensus (MSAC) method to estimate a transformation model that relates a pair of Speeded-Up Robust Features (SURF). Then, the terminus of a glacier is separated from other objects by a semi-automatic Chan-vese level-set segmentation. After that, calving regions in a terminus are detected as a combined difference of Local Binary Patterns (LBP) of two successive images. Clustered points that form a difference image are transformed into polygons representing changed regions by applying the α-shape method. Finally, the areas of changed regions are estimated by the pixel scaling method. The results highlight the performance of the method under normal conditions and reveal the impact of various weather conditions to the performance of the method.

  • 233. Adinugroho, Sigit
    et al.
    Vallot, Dorothée
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Westrin, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Strand, Robin
    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.
    Calving events detection and quantification from time-lapse images in Tunabreen glacier2015Inngår i: Proc. 9th International Conference on Information & Communication Technology and Systems, Piscataway, NJ: IEEE , 2015, s. 61-65Konferansepaper (Fagfellevurdert)
  • 234.
    Adler, Jeremy
    et al.
    Uppsala universitet, Science for Life Laboratory, SciLifeLab. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk cellbiologi.
    Sintorn, Ida-Maria
    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.
    Strand, Robin
    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.
    Parmryd, Ingela
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk cellbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Conventional analysis of movement on non-flat surfaces like the plasma membrane makes Brownian motion appear anomalous2019Inngår i: Communications Biology, ISSN 2399-3642, Vol. 2, artikkel-id 12Artikkel i tidsskrift (Fagfellevurdert)
  • 235.
    Adlertz, Niclas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Implementing a New Register Allocator for the Server Compiler in the Java HotSpot Virtual Machine2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Java HotSpot Virtual Machine currently uses two Just In Time compilers to increase the performance of Java code in execution. The client and server compilers, as they are named, serve slightly different purposes. The client compiler produces code fast, while the server compiler produces code of greater quality. Both are important, because in a runtime environment there is a tradeoff between compiling and executing code. However, maintaining two separate compilers leads to increased maintenance and code duplication. An important part of the compiler is the register allocator which has high impact on the quality of the produced code. The register allocator decides which local variables and temporary values that should reside in physical registers during execution. This thesis presents the implementation of a second register allocator in the server compiler. The purpose is to make the server compiler more flexible, allowing it to produce code fast or produce code of greater quality. This would be a major step towards making the client compiler redundant. The new register allocator is based on an algorithm called the linear scan algorithm, which is also used in the client compiler. The implementation shows that the time spent on register allocation in the server compiler can be greatly reduced with an average reduction of 60 to 70% when running the SPECjvm2008 benchmarks. However, while the new implementation, in most benchmarks, is slower than the register allocator in the client compiler, concrete suggestions on how to improve the speed of the new register allocator are presented. Looking at performance, the implementation is not yet in line the with the client compiler, which in most benchmarks produces code that performs 10 to 25% better. The implementation does, however, have good potential in reaching that performance by implementing additional performance improvements described in this thesis. The benchmark data shows that, while the new implementation looks promising, additional work is needed to reach the same compilation speed and performance as the register allocator in the client compiler. Also, other phases in the server compiler, such as certain optimization phases, also need to be optional and adjustable to further reduce the compilation time.

  • 236.
    Adolfsson, Hampus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Adolfsson, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Wang, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    A Web Application for Daily Staff Coordination in Hospital Care2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Stress and heavy workloads are commonplace for those who work within Swedish healthcare; the issue is exacerbated further by the current shortage of qualified personnel. Therein arises a need for tools to help lessen the burden on the personnel. This report presents a prototype of a web application made for daily staff scheduling, tailored to the needs of the pediatric surgery department at Uppsala University Hospital. The aim of the project was to deliver a more flexible digital solution of daily staff coordination at the department. Two fundamentals of the application were that it should be easy to use and display informationclearly with few misunderstandings. The resulting prototype met the usability requirement, other than a few specific usability issues, and improved upon the readability of the contents displayed in comparison to the previous system. To further improve the system, work could be done to increase the efficiency with which tasks can be performed.

  • 237.
    Adwent, Ann-Kristin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datalogi.
    Shared IT Service Center i kommuner2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    To be able to maintain an adequate IT

    service for various users and needs,

    more municipalities are looking at the

    possibility for mergers of local IT

    departments. One solution for merging

    multiple services/functions and creating

    synergy opportunities is called Shared

    Service Center (SSC). The concept of SSC

    is that the administrative service

    itself becomes a core activity within

    the organization. The aim of this thesis

    is to provide municipalities who are

    considering a merging of their local IT

    departments with recommendations on how

    to design the Shared IT Service Center.

    Recommendations are outlined based on an

    analysis of IT-management literature,

    reports and by conducting a study on

    three ongoing collaborations.

    The conclusions drawn from the study

    suggest guidelines for the design of a

    Shared IT Service Center for

    municipalities. These are as following:

    Create a vision associated with a

    specific and structured target state.

    Identify needs for different target

    groups in municipalities and set a

    common standard.

    Create a clear and practical model/SLA

    appearance of the cooperation and

    agreement.

    Ensure the individual municipalities

    commissioning skills in order to not

    lose it in the context of a common IT

    operation.

    Find an organization that is democratic

    for member municipalities and

    facilitates long-term partnership.

    Specify the operation and maintenance so

    that it can be regulated and controlled

    Establish a common help desk.

    Establish a common standard and

    consolidated infrastructure before the

    introduction of a common technology platform.

  • 238.
    Afridi Asad, Hameed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Development of Microwave sensor and Android Application for monitoringlong bone defects2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Fractures of the long bones are one of the most common injuries. Long bone are always at risk for fractures and require careful treatment to avoid the human disabilities. Microwave technology is using to development of biomedical sensors for detecting and monitoring bone defects. Microwave are electromagnetic (EM) radiation with frequencies between 300MHz and 300 GHz. The microwave technology is used in wireless networking and communication systems, wireless security systems, remote sensing and medical application. The main purpose of this thesis is to investigate rectangular microstrip patch antenna for monitoring long bone defects. A narrow band microwave antenna will be designed, then validate the antenna using measurement. Design an application for mobile, where physicians can easily see the patient’s measurement in a graph form,healing process and physicians can analyze the patient’s health condition.

  • 239.
    Afsarmanesh Tehrani, Nazanin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Clustering Multilayer Networks2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Detecting community structure is an important methodology to study complex networks. Community detection methods can be divided into two main categories: partitioning methods and overlapping clustering methods. In partitioning methods, each node can belong to at most one community while overlapping clustering methods allow communities with overlapping nodes as well. Community detection is not only a problem in single networks today, but also in multilayer networks where several networks with the same participants are considered at the same time. In recent years, several methods have been proposed for recognizing communities in multilayer networks; however, none of these methods finds overlapping communities. On the other hand, in many types of systems, this approach is not realistic. For example, in social networks, individuals communicate with different groups of people, like friends, colleagues, and family, and this determine overlaps between communities, while they also communicate through several networks like Facebook, Twitter, etc. The overall purpose of this study was to introduce a method for finding overlapping communities in multilayer networks. The proposed method is an extension of the popular Clique Percolation Method (CPM) for simple networks. It has been shown that the structure of communities is dependent on the definition of cliques in multilayer networks which are the smallest components of communities in CPM, and therefore, several types of communities can be defined based on different definitions of cliques. As the most conventional definition of communities, it is necessary for all nodes to be densely connected in single networks to form a community in the multilayer network. In the last part of the thesis, a method has been proposed for finding these types of communities in multilayer networks.

  • 240. Agarwal, M
    et al.
    Stoica, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Åhgren, P
    Common factor estimation and two applications in signal prosessing2004Inngår i: Signal Processing, Vol. 84, s. 421-429Artikkel i tidsskrift (Fagfellevurdert)
  • 241. Agarwala, Sunita
    et al.
    Nandi, Debashis
    Kumar, Abhishek
    Dhara, Ashis Kumar
    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.
    Thakur, Sumitra Basu
    Sadhu, Anup
    Bhadra, Ashok Kumar
    Automated segmentation of lung field in HRCT images using active shape model2017Inngår i: Proc. 37th Region 10 Conference, IEEE, 2017, s. 2516-2520Konferansepaper (Fagfellevurdert)
  • 242.
    Agerberg, Gösta
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Solving the Vehicle Routing Problem: using Search-based Methods and PDDL2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this project the optimization of transport planning has been studied. The approach was that smaller transport companies do not have the capability to fully optimize their transports. Their transport optimization is performed at a company level, meaning that the end result might be optimal for their company, but that potential for further optimization exists.

    The idea was to build a collaboration of transport companies, and then to optimize the transports globally within the collaboration. The intent was for the collaboration to perform the same driving assignments but at a lower cost, by using fewer vehicles and drivers, or travel shorter distance, or both combined. This should be achieved by planning the assignments in a smarter way, for example using a company's empty return journey to perform an assignment for another company.

    Due to the complexity of these types of problems, called Vehicle Routing Problem (VRP), shown to be NP-complete, search methods are often used. In this project the method of choice was a PDDL-based planner called LPG-td. It uses enforced hill-climbing together with a best-first search to find feasible solutions. The method was tested for scaling, performance versus another method and against time, as well as together with a real-life based problem.

    The results showed that LPG-td might not be a suitable candidate to solve the problem considered in this project. The solutions found for the collaboration were worse than for the sum of individual solutions, and used more computational time. Since the solution for the collaboration at most should be equal to the sum of individual solutions, in theory, this meant that the planner failed.

  • 243.
    Agnarsson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Simulation of a radar in Flames: a ray based radar model2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this report a radar model is modeled and implemented in a simulation framework

    called Flames. The focus is to investigate how and if electromagnetic waves emitted

    from the radar antenna can be simulated by different methods and how these

    methods can be implemented to work in real-time simulations. The radar model

    developed in this report is based on ray tracing and ray propagation techniques

    developed by the author. The model considers varying refractive indices that

    describes both standard atmospheres and atmospheres where ducting occur.

    Preparatory studies are also made to model ground reflection by ray tracing

    techniques. Other simulation techniques, such as the Finite-Difference Time-Domain

    method and the Split-Step Parabolic Equation method, are furthermore considered

    for radar simulation applications. The results show that ray tracing in conjunction

    with geometrical optics is a valid method for simulating electromagnetic waves in

    simple atmosphere models.

  • 244.
    Agrawal, M
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik. AUTOMATIC CONTROL.
    Stoica, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Besson, O
    Åhgren, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Estimation of nominal directions of arrival and angular spreads of distributed sources2003Inngår i: Signal Processing, Vol. 83, s. 1833-1838Artikkel i tidsskrift (Fagfellevurdert)
  • 245.
    Agrawal, Prerna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Tool And Algorithms for Rapid Source Term Prediction (RASTEP) Based on Bayesian Belief Networks2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In case of an accident in a nuclear power plant (NPP), the fast and cor-rect identification of the NPP state that would give a prediction of a possible radioactive release presents a major challenge to both nuclear power plants and regulators. Such prediction is important so that correct and timely decisions and measures are taken to mitigate accident consequences, such as evacuation of people from areas around the power plant. Recent research work [2][3] proposes analyzing the NPP using the Bayesian Belief Network models as a solution to this problem. A BBN is a graphical model that represents any entity with a set of connected nodes. These nodes represent the random variables and the connections between the nodes represent the conditional dependencies between them [7]. However, the BBN models alone are not suitable for use in off-site locations under high stress conditions by people who are not experts. Hence there arises a need for an interface that would –– - Be easy to operate by non-experts under high stress situations with incomplete knowledge of the plant state. - Provide the more detailed information about the network that is not easy for users to read out from the BBN itself. - Provide good graphical displays of the radioactive release predictions and other statistics of the network. One such tool is developed as a part of this master thesis project. The contribution is twofold –– - Analyzing the user requirements, designing the architecture and development of the tool. - Design and implementation of the algorithms for extracting additional information from the network which is not easy to read out while working directly with the BBN. This kind of information helps the user to take some decisions with entering the observations when the user is not a BBN expert. For instance, it helps the user to know which nodes are important to answer and which nodes can be left out. This also helps the user to interpret the intermediate state of the BBN model of the plant. The tool and the algorithms were evaluated by an expert user in order to assess them based on ease of use, value of the analysis output and the processing time. This project work was carried forward in collaboration with Swedish Radiation Safety Authority (SSM) [8]. SSM is already assessing the tool with the goal to obtain fast and independent predictions of radioactive releases based on plant observations.

  • 246.
    Agrens, Rudolfs Eriks
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Sensor Network for Real-TimeAir Quality Measurement2018Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    In this research, a sensor network for air quality measurement is developed. There is a need for air quality assessment in rapidly developing urban areas. Prolonged real-time monitoring can provide a direct feedback on how increasing traffic and construction work affect air quality. Measures can then be taken to mitigate pollution, reducing health hazards and maintaining the standard of air quality in all areas of the city. A low-cost sensor node is required to be able to cover a larger area using more sensor nodes. Methods for measuring humidity, temperature, particle concentration, as well as the gasses carbon monoxide, nitrogen dioxide and ozone were investigated and a sensor node designed by choosing suitable sensors. Field-testing of the sensor nodes was performed in the center of Uppsala city in collaboration with Uppsala Kommun and Uppsala Stadsteater. The commercially available Air Quality Egg was used as a reference method for sensor calibration and verification of measurement accuracy. The results show that the readings match the reference method well. Even low gas concentrations can be measured with good accuracy. There is future interest from Uppsala Kommun to expand the sensor network for measurements in other areas than the city center.

  • 247. Aguero, Juan Carlos
    et al.
    Goodwin, Graham
    Söderström, Torsten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Yuz, Juan
    Sampled Data Errors in Variables Systems.2009Inngår i: SYSID 2009, IFAC 15th Symposium on System Identification, Saint-Malo, France, July 6-8, 2009., 2009Konferansepaper (Fagfellevurdert)
  • 248. Agüero, Juan C.
    et al.
    Godoy, Boris I.
    Goodwin, Graham C.
    Wigren, Torbjörn
    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.
    Scenario-based EM identification for FIR systems having quantized output data2009Inngår i: Proc. 15th IFAC Symposium on System Identification, International Federation of Automatic Control , 2009, s. 66-71Konferansepaper (Fagfellevurdert)
  • 249. Agüero, Juan C.
    et al.
    Goodwin, Graham C.
    Lau, Katrina
    Wang, Meng
    Silva, Eduardo I.
    Wigren, Torbjörn
    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.
    Three-degree of freedom adaptive power control for CDMA cellular systems2009Inngår i: Proc. 28th Global Telecommunications Conference, IEEE Communications Society, 2009, s. 2793-2798Konferansepaper (Fagfellevurdert)
  • 250.
    Ahani, Ghafour
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Yuan, Di
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    BS-assisted Task Offloading for D2D Networks with Presence of User Mobility2019Inngår i: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Task offloading is a key component in mobile edge computing. Offloading a task to a remote server takes communication and networking resources. An alternative is device-to-device (D2D) offloading, where a task of a device is offloaded to some device having computational resource available. The latter requires that the devices are within the range of each other, first for task collection, and later for result gathering. Hence, in mobility scenarios, the performance of D2D offloading will suffer if the contact rates between the devices are low. We enhance the setup to base station (BS) assisted D2D offloading, namely, a BS can act as a relay for task distribution or result collection. However, this would imply additional consumption of wireless resources. The associated cost and the improvement in completion time of task offloading compose a fundamental trade-off. For the resulting optimization problem, we mathematically prove the complexity, and propose an algorithm using Lagrangian duality. The simulation results demonstrate not only that the algorithm has close-to-optimal performance, but also provide structural insights of the optimal trade-off.

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