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  • 101.
    Carlson, Rolf
    et al.
    Tromsø University.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Simonsen, Geir
    Tromsø University.
    Improvement of kilolab processes when the time constraints are severe2007Ingår i: Proceedings of Optimising Organic Reactions, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 102.
    Carlson, Rolf
    et al.
    Department of Chemistry, University of Tromsoe, Tromsoe, Norway.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grennberg, Anders
    Luleå tekniska universitet.
    A novel approach for screening discrete variations in organic synthesis2001Ingår i: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 15, nr 5, s. 455-474Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we present a general strategy for screening discrete variations in organic synthesis. The strategy is based upon principal properties, i.e. principal component characterization of the constituents defining the reaction system. The first step is to select subsets of test items from each class of constituents defining the reaction space, i.e. substrates, reagents, solvents, catalysts, etc., so that the selected items from each class cover the properties considered. The second step is to construct a candidate matrix which contains all possible combinations of the items in the subsets. This matrix is a full multilevel factorial design. The third step is to assign a tentative model for the screening experiment and to construct the corresponding candidate model matrix. The fourth step is to select experiments to yield an experimental design that spans the variable space efficiently and that also gives good estimates of the model parameters. We present an algorithm that uses singular value decomposition to select experiments. The proposed strategy is then illustrated with an example of the Fischer indole synthesis.

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  • 103.
    Carlson, Rolf
    et al.
    Tromsø University.
    Carlson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grennberg, Anders
    Novel and optimal strategy for screening discrete variations in organic synthesis1999Konferensbidrag (Refereegranskat)
  • 104.
    Carlson, Rolf
    et al.
    Department of Chemistry, University of Tromsoe.
    SImonsen, Geir
    Department of Chemistry, University of Tromsoe.
    Descomps, Alexandre
    Department of Chemistry, University of Tromsoe.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Identification of important experimental variables in organic synthetic procedures by near-orthogonal experiments2012Ingår i: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 16, nr 8, s. 1371-1377Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new strategy is presented for the design of screening experiments in synthetic chemistry when the objective is to identify the important experimental variables from a limited number of experimental runs. The methodology is based on Taylor expansion (response surface) models The experimental design is constructed in such a way that the vector of the variables in the Taylor model in each run are near-orthogonal to each other. This is achieved by laying out a grid of possible experiments in the experimental space, expanding this candidate experimental design matrix to the corresponding model matrix, i.e. the matrix containing columns for all variables in the Taylor expansion. This model matrix is then factorised by singular value decomposition, SVD. The row in the model matrix that is most parallel to the first singular vectors is selected as the first experiment. .The variation displaced by this first experiment is removed from the elements of the model matrix by projections. The resulting matrix is the orthogonal complement to the first selected row. The procedure is repeated until all dimensions of the model space have been spanned by the selected experiments The singular vectors are mutually orthogonal, and selected experiments will be nearly orthogonal and span the dimensions of the model space. The experiments can be run in sequence and thus allow for a systematic search, one experiment at a time. It is shown that subset selections from such designs in combination with PLS modelling can be used to identify the important variables. The principles are illustrated with two examples: (a) a dibromination of an acetyl with four experimental variables and (b) a synthesis of an enamine by condensing a ketone and morpholine in the presence of molecular sieves in which seven experimental variables are involved. In the acetal bromination, it was found that 5 experiments out of 12 were sufficient for identifying the most important variables. In the enamine example, 8 experiments out of 30 were sufficient.

  • 105.
    Carlson, Rolf
    et al.
    Department of Chemistry, University of Tromsoe.
    Simonsen, Geir
    Department of Chemistry, University of Tromsoe.
    Descomps, Alexandre
    Department of Chemistry, University of Tromsoe.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Near-orthogonal experiments in explorative synthetic organic chemistry2009Konferensbidrag (Övrigt vetenskapligt)
  • 106.
    Carlson, Rolf
    et al.
    Department of Chemistry, University of Tromsoe.
    Simonsen, Geir
    Department of Chemistry, University of Tromsoe.
    Descomps, Alexandre
    Department of Chemistry, University of Tromsoe.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Orthogonal experiments in the development of organic synthetic processes2009Ingår i: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 13, nr 4, s. 798-803Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new strategy is presented for the design of explorative experiments in synthetic chemistry when the objective is to identify the important experimental variables. The methodology is based on Taylor expansion (response surface) models, and the principles are: A grid of possible settings of the experimental variables is laid out in the experimental domain. These experiments define a candidate design matrix, DC. From DC, a candidate model matrix, XC is defined by appending columns for each variable in the Taylor model XC is then factored by singular value decomposition (SVD), and XC = USVT. The rows in XC that are most parallel to the singular column vectors in V are selected, and the corresponding experiments in DC are identified. This gives the experimental design. The selected experiments are nearly orthogonal, and they span the dimensions of the model space. The experiments can be run in sequence, and thus, they allow for a systematic search, one experiment at a time. The design principles are illustrated by an example of the dibromination of an acetal. Four variables were studied, and from 12 experiments, all the main effects and all two-factor interaction effects were estimated. From the response surface model, conditions for quantitative yield were predicted, and a mol-scale synthesis carried out under these conditions afforded 98% yield of the isolated pure, >97% product.

  • 107.
    Carmona Velazquez, Diana
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Recording Bass-Cabinet: Microphone Choice and Microphone Placement2023Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Research on microphone choice and placement has been previously made for a variety of instruments, such as drums, vocals, and guitar, to name a few. However, in comparison, very little research has been made on the bass-cabinet. With help of the different methodologies used for previous research on electric guitar and snare drum, the optimal placement and choice of microphone for a 4x10” bass-cabinet were investigated. In a listening test, pre-recorded basslines were mixed with other instruments since it is more common to hear it in a mix of instruments rather than listening to it by itself. To make sure that the topic is not too broad, focus on the genre of rock was taken for this investigation. Both qualitative and quantitative data were collected in a set of listening tests where the subjects rated their preference for their most and least preferable basslines. The subjects were asked to describe their preference utilizing different characteristics of the stimuli. An ANOVA test provided evidence that there is a statistical difference between the preference of one microphone model at a 15 cm distance from the bass-cabinet, in the category bass with band.

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    Recording Bass-Cabinet, Diana Carmona
  • 108.
    Casselgren, Johan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Sjödahl, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Leblanc, James
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Angular spectral response from covered asphalt2007Ingår i: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 46, nr 20, s. 4277-4288Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By measuring the spectral reflection from the four different road conditions dry, wet, icy, and snowy asphalt, a method of classification for the different surfaces -- using two and three wavelengths -- is developed. The method is tested against measurements to ascertain the probability of wrong classification between the surfaces. From the angular spectral response, the fact that asphalt and snow are diffuse reflectors and water and ice are reflective are confirmed.

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  • 109.
    Casselgren, Johan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Sjödahl, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Leblanc, James P.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Model-based winter road classification2012Ingår i: International Journal of Vehicle Systems Modelling and Testing, ISSN 1745-6436, E-ISSN 1745-6444, Vol. 7, nr 3, s. 268-284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An investigation of different road conditions has been conducted using a short-wave infrared (SWIR) light online sensor to examine the possibility of estimating road condition parameters such as porosity, depth and roughness. These parameters are essential for non-contact road friction estimation. The investigation show that it is possible to detect changes of depths of water and ice as well as classify different types of ice, by utilising polarised short-wave infrared (SWIR) light and a modified Hapke directional reflectance model

  • 110.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Control configuration selection for integrating processes using graphs2015Ingår i: 2015 IEEE International Conference on Control Applications (CCA 2015): Sydney, Australia, September 21-23, Piscataway, NJ: IEEE Communications Society, 2015, s. 1606-1611, artikel-id 7320839Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recently, methods for Control Configuration Selection (CCS) using weighted graphs have been introduced. These methods were integrated in a software tool which allows systematic CCS in industry processes by choosing a simplified model with a reduced structure on which control will be based. This paper addresses the extension of these graph-based methods to be applied to integrating systems, which often appear in industry processes, e.g. at storage vessels. The extension is based on restricting the analysis to a set of frequencies of interest which omits the infinite DC-gain. The results are validated and illustrated using a real-life case, namely the secondary heating system of a pulp & paper mill.

  • 111.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Risberg, Robert
    Creo Dynamics AB.
    Weston, Miles
    TWI Technology Centre Wales.
    3D Synthetic Aperture Imaging Using a Water-Jet Coupled Large-Aperture Single Transducer2014Konferensbidrag (Övrigt vetenskapligt)
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    abstract
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  • 112.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Estimation of Gramian-Based Interaction Measures for Weakly Nonlinear Systems2015Ingår i: 2015 European Control Conference (ECC): Linz, 15-17 July 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 2438-2443Konferensbidrag (Refereegranskat)
    Abstract [en]

    A critical step in the control design of industrial processes is the Control Configuration Selection (CCS), where each actuator is grouped with a set of measurements to be used in the computation of its control action.Tools for CCS include gramian-based Interaction Measures (IMs), initially defined for linear systems. Since a trending research topic is the derivation of IMs for non-linear systems, a decision of the designer is therefore the approach to the problem in the linear or non-linear framework. For this end, a method is discussed that determines the degree of nonlinearity of a system based on a specially tailored experiment, and thus enables the selection of the correct framework for the analysis. The novelty is in the estimation of two gramian-based IMs with confidence bounds from the tailored experiment which is applicable if the process is revealed to be weakly non-linear. If the process is found to be strongly non-linear, then alternative approaches for the interaction analysis have to be considered.

  • 113.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Rönnberg, Johan Karlsson
    K Algorithm Design.
    Systematic Control Configuration Selection of Secondary Heating Systems: A Case Study2014Konferensbidrag (Övrigt vetenskapligt)
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  • 114.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Rönnberg, Johan Karlsson
    K Algorithm Design.
    Systematic Control Configuration Selection of Secondary Heating Systems: A Case Study2014Konferensbidrag (Övrigt vetenskapligt)
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    FULLTEXT01
  • 115.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Risberg, Robert
    Creo Dynamics AB.
    Weston, Miles
    TWI Technology Centre Wales.
    3D Synthetic Aperture Imaging Using a Water-Jet Coupled Large-Aperture Single Transducer2014Konferensbidrag (Övrigt vetenskapligt)
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    FULLTEXT01
  • 116.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Weston, Miles
    TWI Technology Centre Wales.
    Risberg, Robert
    Creo Dynamics AB.
    3D Synthetic Aperture Imaging Using a Water-Jet Coupled Large Aperture Single Transducer2014Ingår i: 2014 IEEE International Ultrasonics Symposium (IUS 2014): Chicago, Ill. 3-6 September 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 1372-1375Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a technique for in-situ non-destructive testing of materials with applications in railway crossings. The novelty is in successfully applying the Virtual Source (VS) concept using water jet coupling for a large transducer. By focusing the sound field at the surface of the sample, the water jet probe can be built with a small nozzle opening, limiting the water consumption and making it viable for field applications. The annular geometry of the large transducer ensures the spherical wavefront assumed in the application of the SAFT algorithm, which usually limits the size of the transducer

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  • 117. Castro, Julio E.
    et al.
    Leblanc, James
    Rapajic, Predrag
    A multidimensional adaptive linear receiver for CDMA transmission corrupted by SD-MTI1999Ingår i: Asilomar Conference on Signal, Systems, and Computers, IEEE Communications Society, 1999, s. 927-930Konferensbidrag (Refereegranskat)
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  • 118. Castro, Julio E.
    et al.
    Leblanc, James
    Rapajic, Predrag
    Multidimensional extension of MMSE linear adaptive receiver for DSSS systems1999Ingår i: Signal Processing and Its Applications: ISSPA '99. Proceedings, Piscataway, NJ: IEEE Communications Society, 1999, s. 915-918Konferensbidrag (Refereegranskat)
    Abstract [en]

    We extend the single channel adaptive linear receiver (ALR) to the multidimensional case. The extension is used for the cancellation of strong spatially-distributed narrowband interference in direct sequence spread spectrum communications. Simulations show a gain of 8 dB for the case of two interferences occupying 30% of the bandwidth of the spread spectrum signal

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    FULLTEXT01
  • 119.
    Cendrillon, Raphael
    et al.
    Marvell Hong Kong Ltd.
    Collings, Iain
    CSIRO Information Communication Technologies Center.
    Nordström, Tomas
    Telecommunications Research Center Vienna.
    Sjöberg, Frank
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Tsatsanis, Michail
    Aktino Inc., Irvine.
    Yu, Wei
    Electrical and Computer Engineering Department, University of Toronto.
    Advanced signal processing for digital subscriber lines2006Ingår i: EURASTP journal an applied signal processing, ISSN 1110-8657, E-ISSN 1687-0433Artikel i tidskrift (Refereegranskat)
  • 120.
    Centing, Viktor
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Approximating material area, volume,and velocity for belt conveyor systemapplications using 3D depth sensor technology2023Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Time of Flight (ToF) technology describes products or systems which measure distance by calculating the distance emitted light travels before bouncing off its surroundings and ending back up at the system. Since the early 2000s, many advancements in the area of ToF systems have been made leading to much use for the ToF variant LiDAR. Alternative technologies are on the rise, one of which is 3D ToF depth sensors. This report explores ToF depth sensor technology within the setting of belt conveyor system (BCS)applications. More specifically, methods for area, volumetric, and velocity approximation are explored and a comparison is also made against LiDAR. The aim of the report is split. One part aims to compare the accuracy of a ToF depth sensor to a 2D LiDAR scanner. The second one is to propose algorithms that, using only a ToF depth sensor, calculate the volume of material transported by a BCS and approximate the velocity at which said material is traveling. Methods for testing include strictly experimental setups in a controlled environment where both technologies were used to collect data on selected scenes. Results indicate that ToF depth sensors can achieve accuracy equivalent to LiDAR sensors. ToF depth sensors can resolve the volume of objects with relatively good results and algorithms that are not computationally complex. By implementing a proposed algorithm, the velocity of material traveling on a BCS was able to be approximated with up to 99% accuracy. However, effects of common sources of error are present in the result and hence have to be considered moving forward. Therefore, this report also highlights future improvements to establish a more robust methodology and reduce errors. The results can be used to improve current BCS, such as increased range of functionality, reduced costs, and raised quality control while also aiding in the enabling of Industry 4.0 implementation. 

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  • 121.
    Cheung, Lawrence
    et al.
    CSIRO, Australia.
    Poniewierski, Julian
    ICI.
    Ward, Barry
    CSIRO, Australia.
    LeBlanc, David
    CSIRO, Australia.
    Thurley, Matthew
    SIROJOINT and SIROFRAG: new techniques for joint mapping and rock fragment size distribution measurement1996Ingår i: Rock Fragmentation by Blasting: proceedings of the Fifth International Symposium on Rock Fragmentation by Blasting - FRAGBLAST-5, Montreal, Quebec, Canada, 25 - 29 August 1996 / [ed] Bibhu Mohanty, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1996, s. 253-258Konferensbidrag (Refereegranskat)
  • 122.
    Chhipa, Prakash Chandra
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Upadhyay, Richa
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Saini, Rajkumar
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindqvist, Lars
    Optimation Advanced Measurements AB, Luleå, Sweden.
    Nordenskjold, Richard
    Optimation Advanced Measurements AB, Luleå, Sweden.
    Uchida, Seiichi
    Human Interface Laboratory, Kyushu University, Fukuoka, Japan.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Depth Contrast: Self-supervised Pretraining on 3DPM Images for Mining Material Classification2022Ingår i: Computer Vision – ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23–27, 2022, Proceedings, Part VI / [ed] Avidan, S.; Brostow, B.; Cissé, M.; Farinella, G.M.; Hassner, H., Springer Nature, 2022, Vol. VI, s. 212-227Konferensbidrag (Refereegranskat)
  • 123.
    Chiaraviglio, Luca
    et al.
    CNIT, Italy.
    Blefari-Melazzi, Nicola
    CNIT, Italy.
    Liu, William
    AUT, New Zealand.
    Gutierrez, Jairo A.
    AUT, New Zealand.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birke, Robert
    IBM Research, Switzerland.
    Chen, Lydia
    IBM Research, Switzerland.
    Idzikowski, Filip
    Faculty of Electronics and Telecommunications, Poznan University of Technology.
    Kilper, Daniel
    The University of Arizona.
    Monti, Paolo
    KTH Royal Institute of Technology.
    Wu, Jinsong
    University of Chile.
    5G in rural and low-income areas: Are we ready?2017Ingår i: Proceedings of the 8th ITU Kaleidoscope academic conference: ICTs for a Sustainable World, Piscataway, NJ: IEEE Communications Society, 2017, s. 99-106, artikel-id 7805720Konferensbidrag (Refereegranskat)
    Abstract [en]

    Current trends in telecommunication networks foresee the adoption of the,fifth generation (5G) of wireless networks in the near fixture. However; a large number of people are living without coverage and connectivity. To face this issue, we consider the possibility of deploying 5G networks in rural and low-income zones. After detailing the current state-of-the-art, we consider the main challenges that need to be faced. Moreover; we define the main pillars to follow in order to deploy 5G networks in such zones, as well as a proposal of a future network architecture.

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  • 124.
    Chiaraviglio, Luca
    et al.
    Consorzio Nazionale Interuniversitario per le Telecomunicazioni and University of Rome Tor Vergata.
    Blefari-Melazzi, Nicola
    Consorzio Nazionale Interuniversitario per le Telecomunicazioni and University of Rome Tor Vergata.
    Liu, William
    Auckland University of Technology.
    Gutiérrez, Jairo A.
    Auckland University of Technology.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birke, Robert
    IBM Research, Switzerland.
    Chen, Lydia
    IBM Research.
    Idzikowski, Filip
    Poznan University of Technology.
    Kilper, Daniel
    University of Arizona.
    Monti, Paolo
    KTH Royal Institute of Technology.
    Bagula, Antoine
    University of Western Cape.
    Wu, Jinsong
    University of Chile.
    Bringing 5G into Rural and Low-Income Areas: Is It Feasible?2017Ingår i: IEEE Communications Standards Magazine, ISSN 2471-2825, Vol. 1, nr 3, s. 50-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nowadays, at least two billion people are experiencing a complete lack of wireless cellular network coverage. These users live in rural areas and low-income regions, where network operators are not keen to invest, mainly due to high capital expenditure and operational expenditure costs, as well as the scarcity of electricity from the grid. We tackle this challenge by proposing a 5G network explicitly designed to serve rural and low-income areas. Our solution investigates the possibility of mounting remote radio heads on top of unmanned aerial vehicles, as well as large cells (LCs) to increase the coverage range. In addition, 5G nodes are powered by solar panels and batteries. Preliminary results, obtained over three representative case studies located in Italy, Cook Islands, and Zimbabwe, show that providing connectivity in rural and low-income areas by means of the proposed 5G architecture is feasible. At the same time, we also show that the monthly subscription fee paid by the users can be kept sufficiently low, that is, less than €1/month in low-income areas, and around €11/month in rural regions.

  • 125.
    Chintalapati, Bharadwaj
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Airbus Defence and Space GmbH, Friedrichshafen,Claude-Dornier Strasse, 88090 Immenstaad am Bodensee, Germany.
    Precht, Arthur
    Airbus Defence and Space GmbH, Friedrichshafen,Claude-Dornier Strasse, 88090 Immenstaad am Bodensee, Germany.
    Hanra, Sougata
    Airbus Defence and Space GmbH, Friedrichshafen,Claude-Dornier Strasse, 88090 Immenstaad am Bodensee, Germany.
    Laufer, Rene
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eickhoff, Jens
    Airbus Defence and Space GmbH, Friedrichshafen,Claude-Dornier Strasse, 88090 Immenstaad am Bodensee, Germany; University of Stuttgart, Postfach 10 60 37, 70049 Stuttgart, Germany.
    Opportunities and challenges of on-board AI-based image recognition for small satellite Earth observation missions2024Ingår i: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The satellite industry is rapidly growing. There has been a significant increase in the number of new small satellites that are launched, which is complemented by the rapid pace of the development of image recognition algorithms. Convolutional neural networks (CNNs) in particular, have achieved state-of-the-art performance in computer vision related applications. Combining both and running an AI algorithm on-board the satellite to observe and recognize any natural disaster directly from the orbit is an important opportunity. This paper presents notable challenges that are generally involved in an Earth Observation small satellite mission and further challenges that are posed by combining it with AI-based image recognition on-board the satellite. This study discusses an approach that is feasible mainly for a fleet of small satellites.

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  • 126.
    Chopra, Muskaan
    et al.
    Chandigarh College of Engineering and Technology, Punjab University, Chandigarh, India.
    Chhipa, Prakash Chandra
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Mengi, Gopal
    Chandigarh College of Engineering and Technology, Punjab University, Chandigarh, India.
    Gupta, Varun
    Chandigarh College of Engineering and Technology, Punjab University, Chandigarh, India.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Domain Adaptable Self-supervised Representation Learning on Remote Sensing Satellite Imagery2023Ingår i: IJCNN 2023 - International Joint Conference on Neural Networks, Conference Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2023Konferensbidrag (Refereegranskat)
    Abstract [en]

    This work presents a novel domain adaption paradigm for studying contrastive self-supervised representation learning and knowledge transfer using remote sensing satellite data. Major state-of-the-art remote sensing visual domain ef-forts primarily focus on fully supervised learning approaches that rely entirely on human annotations. On the other hand, human annotations in remote sensing satellite imagery are always subject to limited quantity due to high costs and domain expertise, making transfer learning a viable alternative. The proposed approach investigates the knowledge transfer of self-supervised representations across the distinct source and target data distributions in depth in the remote sensing data domain. In this arrangement, self-supervised contrastive learning- based pretraining is performed on the source dataset, and downstream tasks are performed on the target datasets in a round-robin fashion. Experiments are conducted on three publicly avail-able datasets, UC Merced Landuse (UCMD), SIRI-WHU, and MLRSNet, for different downstream classification tasks versus label efficiency. In self-supervised knowledge transfer, the pro-posed approach achieves state-of-the-art performance with label efficiency labels and outperforms a fully supervised setting. A more in-depth qualitative examination reveals consistent evidence for explainable representation learning. The source code and trained models are published on GitHub1.

  • 127.
    Cichoń, Krzysztof
    et al.
    Institute of Radiocommunications, Poznan University of Technology, Poznań, 60-965, Poland.
    Nikiforuk, Maciej
    Tietoevry, al. Piastów 30, Szczecin, 71-064, Poland.
    Kliks, Adrian
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system. Institute of Radiocommunications, Poznan University of Technology, Poznań, 60-965, Poland.
    Vegetation Loss Measurements for Single Alley Trees in Millimeter-Wave Bands2024Ingår i: Sensors, E-ISSN 1424-8220, Vol. 24, nr 10, artikel-id 3190Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As fixed wireless access (FWA) is still envisioned as a reasonable way to achieve communications links, foliage attenuation becomes an important wireless channel impairment in the millimeter-wave bandwidth. Foliage is modeled in the radiative transfer equation as a medium of random scatterers. However, other phenomena in the wireless channel may also occur. In this work, vegetation attenuation measurements are presented for a single tree alley for 26–32 GHz. The results show that vegetation loss increases significantly after the second tree in the alley. Measurement-based foliage losses are compared with model-based, and new tuning parameters are proposed for models.

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  • 128.
    Compierchio, Angelo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Oyelere, Solomon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Karagiannis, Chris
    Gesellschaft für Schwerionenforschung (GSI) Helmholtzzentrum GmbH, Darmstadt, Germany.
    Assistive VR platform design for Telemanipulation at the Super Fragment Separator Facility2023Ingår i: Human Interaction and Emerging Technologies (IHIET-AI 2023): Artificial Intelligence and Future Applications: Proceedings of the 9th International Conference on Human Interaction and Emerging Technologies: Future Applications (IHIET – AI 2023), April 13-15, 2023, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland / [ed] Ahram, T., Taiar, R., AHFE International , 2023, s. 186-197Konferensbidrag (Refereegranskat)
    Abstract [en]

    An assisted remote manipulation (ArM) platform has been defined for the Super FragmentSeparator (Super-FRS) main tunnel and hot cell at the High Energy Physics (HEP) Facilityof Anti-proton and Ion Research (FAIR). The designed platform positioned within a VirtualReality (VR) based framework ensures dynamic collaboration and effective humaninteraction to assist with Remote Handling (RH) operations. To visually stimulate operatorassisted intervention in harsh environments, enhanced interaction based on syntheticvision has been adapted with simultaneous localization and mapping (SLAM) techniquesinterlinked with virtual layers representing a three dimensional manipulation of RHmaintenance tasks. The proposed platform also included a sequence mapping toolevaluated with RH task variables specific to the sequence space analyses of pathplanning, motion check, and collision detection performed in both real and virtual RH taskenvironments. Further assistance was envisaged from multimodal feedback categoriesthrough force feedback, in this case, a backpropagation algorithm was tailored to define aforce limit and to send feedback signals to the operator every time the actual patternexceeded the desired output pattern. Overall, the ArM platform ensures the application ofbest engineering practices to RH needs as a basis to maximize information gathering andsharing driven by continuous improvement initiatives.

  • 129.
    Curic, Vladimir
    et al.
    Centre for Image Analysis, Uppsala University and Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Landström, Anders
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Thurley, Matthew J.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Luengo Hendriks, Cris L.
    Centre for Image Analysis, Uppsala University and Swedish University of Agricultural Sciences.
    Adaptive mathematical morphology – A survey of the field2014Ingår i: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 47, s. 18-28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present an up-to-date survey on the topic of adaptive mathematical morphology. A broad review of research performed within the field is provided, as well as an in-depth summary of the theoretical advances within the field. Adaptivity can come in many different ways, based on different attributes, measures, and parameters. Similarities and differences between a few selected methods for adaptive structuring elements are considered, providing perspective on the consequences of different types of adaptivity. We also provide a brief analysis of perspectives and trends within the field, discussing possible directions for future studies.

  • 130. Davis, Edward W.
    et al.
    Nordström, Tomas
    Luleå tekniska universitet.
    Svensson, Bertil
    Chalmers University of Technology.
    Issues and applications driving research in non-conforming massively parallel processors1992Ingår i: Proceedings, The New Frontiers: A Workshop on Future Directions of Massively Parallel Processing, IEEE Communications Society, 1992, s. 68-78Konferensbidrag (Refereegranskat)
  • 131.
    Edfors, Ove
    Luleå tekniska universitet.
    Low-complexity algorithms in digital receivers1996Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis addresses low-complexity algorithms in digital receivers. This includes algorithms for estimation, detection, and source coding. Low-complexity algorithms for estimation and detection, in this thesis concerns the approximation of optimal algorithms, so that a low complexity is obtained while most of the original performance is maintained. Two different problems are studied: Channel estimation in orthogonal frequency-division multiplexing (OFDM) systems and sequence detection in systems with inter-symbol interference (ISI). The work on channel estimation is focused on what can be viewed as transform-based estimators, where the estimation is transformed to a domain that allows the statistical properties of the channel to be used efficiently for complexity reduction. Estimators based both on the discrete Fourier transform (DFT) and on low-rank approximations are addressed. It is shown that these types of estimators, with proper design considerations, provide good low-complexity estimators, even though the DFT-based estimators have a tendency to suffer from approximation errors at high signal-to-noise ratios. The work on sequence detection in systems with ISI is a comparative study of designs in a class usually referred to as combined linear-Viterbi equalizers (CLVEs). The idea behind CLVEs is to shorten the impulse response of the channel by a linear prefiltering, before the Viterbi detector is applied. The comparison includes three previously known designs and a minimax design. A unified design-framework is also derived, which makes the comparison easier. The last two parts of the thesis are concerned with the design of robust variable-length codes and an analysis of the decoding speed for look-uptable based decoders for variable-length codes, respectively. By robust variable-length codes are meant fixed variable-length codes that have a low susceptibility to changes in the probability distribution of the source. Robustness measures are discussed in general and a measure called gradient robustness is introduced. It is shown that only a small loss in the degree of data compression can result in substantially increased robustness. As a side effect the proposed design methods also shorten the length of the longest code words, allowing efficient storage of code books. Finally, the design and the decoding speed of look-up table based decoders for variable-length codes are studied. These decoders are based on using the coded sequence for indexing a table, thereby providing an instantaneous decoding. Two types of decoders are studied. One allows a trade-off between decoding speed and memory requirement.

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  • 132.
    Edfors, Ove
    Luleå tekniska universitet.
    On robust source codes and fast look-up table decoding1993Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 133.
    Edfors, Ove
    et al.
    Luleå tekniska universitet.
    Börjesson, Per Ola
    Luleå tekniska universitet.
    Design and analysis of robust source codes1993Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this report, we are proposing a framework for robustness analysis of source codes, in combination with a design procedure for finding an optimal robust code. The robustness is defined as low susceptibility to changes in the probability distribution of the source. In many applications, the probability distribution is not well known, nor time-invariant. Hence, by introducing a robustness measure we can design a code, based on a relatively poor estimate of the probability distribution, without risking a catastrophic increase of the average code word length if the estimate was incorrect or the source characteristics change. The basic concepts are robustness in general, and gradient robustness in particular. The gradient robustness, $R_\nabla (\QTR{cal}{C})$ of a variable-length code, $\QTR{cal}{C}$, with code word lengths $l_i$, $i=0\ldots N-1$, is defined as $R_\nabla (C)=\left( \sum_{i=0}^i(l_i-\overline{l})^2\right) ^{-1/2}$, where $\overline{l}$ is the arithmetic mean of the code word lengths. In the experimental part, it is shown that even a small loss in the degree of compression can give a substantial increase of the robustness of the code. The procedure for finding the optimal robust code is computationally intense, but an easy to compute approximation formula is given. The experiments performed, using the approximation formula, only lead to minor differences in the obtained robustness, compared to the optimal robust code. Some of the observations done in the experiments are: The lengths of the longest code words are reduced when introducing robustness, thus reducing the required memory space for storing code books. When the experiments on entropy-close codes are applied to Huffman codes, we get roughly the same results. The differences is due to the quantization of code word lengths in the Huffman code. Three different methods for measuring the behaviour of the gradient robust codes, compared to the optimal data compression codes, are showing promising results. The analysis and experiments in this report only cover a small part of the possibilities, but the results obtained are providing incentive for further studies. A robustness measure we are planning to investigate in the future is based on the arithmetic mean of the code word costs.

  • 134.
    Edfors, Ove
    et al.
    Luleå tekniska universitet.
    Börjesson, Per Ola
    Luleå tekniska universitet.
    Erendi, Alex
    Luleå tekniska universitet.
    A performance analysis of look-up table based variable-length decoders1993Rapport (Övrigt vetenskapligt)
  • 135.
    Edfors, Ove
    et al.
    Luleå tekniska universitet.
    Börjesson, Per Ola
    Luleå tekniska universitet.
    Erendi, Alex
    Luleå tekniska universitet.
    Analysis of a fast algorithm for look-up table based variable-length decoding1993Ingår i: Radiovetenskaplig konferens på Lunds tekniska högskola 5-7 april 1993: sammanfattning av posters och föredrag / RVK-93, Lund: Lunds tekniska högskola , 1993, s. 181-184Konferensbidrag (Refereegranskat)
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  • 136.
    Edfors, Ove
    et al.
    Luleå tekniska universitet.
    Sandell, Magnus
    Luleå tekniska universitet.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Landström, Daniel
    Luleå tekniska universitet.
    Sjöberg, Frank
    Luleå tekniska universitet.
    An introduction to orthogonal frequency-division multiplexing1997Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report is an introduction to orthogonal frequency-division multiplexing (OFDM). The focus is on signal processing areas pursued by our research group at Luleå University of Technology. We present an historical background and some frequently used system models. Typical areas of applications are also described, both wireless and wired. In addition to the general overview, the addressed areas include synchronization, channel estimation and channel coding. Both time and frequency synchronization are described, and the effects of synchronization errors are presented. Different types of channel estimators are described, where the focus is on low-complexity algorithms, and in this context, advantages and disadvantages of coherent and differential modulation are also discussed. Channel coding is described, both for wireless and wired systems, and pointers are included to evaluation tools and bitloading algorithms. An extensive bibliography is also included.

  • 137.
    Edfors, Ove
    et al.
    Luleå tekniska universitet.
    Sandell, Magnus
    Luleå tekniska universitet.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Landström, Daniel
    Luleå tekniska universitet.
    Sjöberg, Frank
    Luleå tekniska universitet.
    An introduction to orthogonal frequency-division multiplexing1997Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report is an introduction to orthogonal frequency-division multiplexing (OFDM). The focus is on signal processing areas pursued by our research group at Luleå University of Technology. We present an historical background and some frequently used system models. Typical areas of applications are also described, both wireless and wired. In addition to the general overview, the addressed areas include synchronization, channel estimation and channel coding. Both time and frequency synchronization are described, and the effects of synchronization errors are presented. Different types of channel estimators are described, where the focus is on low-complexity algorithms, and in this context, advantages and disadvantages of coherent and differential modulation are also discussed. Channel coding is described, both for wireless and wired systems, and pointers are included to evaluation tools and bitloading algorithms. An extensive bibliography is also included.

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  • 138.
    Edfors, Ove
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sandell, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    An application of the singular value decomposition to OFDM channel estimation1996Ingår i: Proceedings of the 1996 SNRV and NUTEK Conference on Radio Sciences and Telecommunications in Luleå and Kiruna June 3-6, 1996: RVK 96 / [ed] Lars H. Zetterberg, Luleå: Luleå tekniska universitet, 1996, s. 678-682Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new approach to low-complexity channel estimation in orthogonal-frequency division multiplexing (OFDM) systems is described. A low-rank approximation is applied to a linear minimum mean-squared error (LMMSE) estimator that uses the frequency correlation of the channel. By using the singular-value decomposition (SVD) an optimal low-rank estimator is derived, where performance is essentially preserved - even for low computational complexities. A fixed estimator, with nominal values for channel correlation and signal-to-noise ratio (SNR), is analysed. Analytical mean-squared error (MSE) and symbol-error rates (SER) are presented for a 16-QAM OFDM system.

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  • 139.
    Edfors, Ove
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sandell, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Analysis of DFT-based channel estimators for OFDM1996Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this paper we analyze the performance of three low-complexity channel estimators, based on the discrete Fourier-transform (DFT), for orthogonal frequency-division multiplexing (OFDM) systems. Estimators of this type have been analyzed for discrete-time channels, and we extend this analysis to continuous-time channels. We present analytical expressions for their mean-squared error (MSE) and evaluate their complexity versus symbol-error rate (SER) for 16-QAM. The analysis shows that this type of estimators may experience an irreducible error floor at high SNRs. However, in one of the three estimators the error floor can be eliminated while the complexity stays low and the performance is maximized.

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  • 140.
    Edfors, Ove
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sandell, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    OFDM channel estimation by singular value decomposition1996Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this report we present and analyse low-rank channel estimators for orthogonal frequency-division multiplexing (OFDM) using the frequency correlation of the channel. Low-rank approximations based on the discrete Fourier transform (DFT) have been proposed but they suffer from poor performance when the channel is not sample-spaced. We apply the theory of optimal rank-reduction to linear minimum mean-squared error (LMMSE) estimators and show that these estimators, when using a fixed design, are robust to changes in channel correlation and signal-to-noise ratio (SNR). The performance is presented in terms of uncoded symbol-error rate (SER) for a system using 16-QAM.

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  • 141.
    Edfors, Ove
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sandell, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    van de Beek, Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wilson, Sarah Kate
    School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
    Börjesson, Per Ola
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    OFDM channel estimation by singular value decomposition1996Ingår i: Mobile technology for the human race: 1996 IEEE 46th Vehicular Technology Conference, Atlanta, Georgia, USA, April 28 - May 1, 1996 / [ed] Jim Worsham, Piscataway, NJ: IEEE Communications Society, 1996, s. 923-927Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new approach to low-complexity channel estimation in orthogonal-frequency division multiplexing (OFDM) systems is proposed. A low-rank approximation is applied to a linear minimum mean-squared error (LMMSE) estimator that uses the frequency correlation of the channel. By using the singular-value decomposition (SVD) an optimal low-rank estimator is derived, where performance is essentially preserved - even for low computational complexities. A fixed estimator, with nominal values for channel correlation and signal-to-noise ratio (SNR), is analysed. Analytical mean-squared error (MSE) and symbol-error rates (SER) are presented for a 16-QAM OFDM system.

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  • 142.
    Edfors, Ove
    et al.
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Sandell, Magnus
    Bell Labs, Lucent Technologies, Swindon, U.K..
    van de Beek, Jan-Jaap
    Nokia Svenska AB, R&D, Kista, Sweden.
    Wilson, Sarah Kate
    Luleå tekniska universitet.
    Börjesson, Per Ola
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Analysis of DFT-Based Channel Estimators for OFDM2000Ingår i: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 12, nr 1, s. 55-70Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we analyze the performance of three low-complexity channel estimators, based on the discrete Fourier transform (DFT), for orthogonal frequency-division multiplexing (OFDM) systems. Estimators of this type have been analyzed for discrete-time channels, and we extend this analysis to continuous-time channels. We present analytical expressions for their mean-squared error (MSE) and evaluate their complexity vs. symbol-error rate (SER) for 16-QAM. The analysis shows that this type of estimators may experience an irreducible error floor at high SNRs. However, in one of the three estimators the error floor can be eliminated while the complexity stays low and the performance is maximized.

  • 143.
    Edfors, Ove
    et al.
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Sandell, Magnus
    Bell Laboratories, Lucent Technologies Inc., Swindon, UK.
    van de Beek, Jan-Jaap
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wilson, Sarah Kate
    Luleå tekniska universitet.
    Börjesson, Per-Ola
    Luleå tekniska universitet.
    OFDM channel estimation by singular value decomposition1998Ingår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 46, nr 7, s. 931-939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present and analyze low-rank channel estimators for orthogonal frequency-division multiplexing (OFDM) systems using the frequency correlation of the channel. Low-rank approximations based on the discrete Fourier transform (DFT) have been proposed, but these suffer from poor performance when the channel is not sample spaced. We apply the theory of optimal rank-reduction to linear minimum mean-squared error (LMMSE) estimators and show that these estimators, when using a fixed design, are robust to changes in channel correlation and signal-to-noise ratio (SNR). The performance is presented in terms of uncoded symbol-error rate (SER) for a system using 16-quadrature amplitude modulation (QAM).

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  • 144.
    Ekvall, Linus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Airborne Radar Ground Clutter Suppression Using Multitaper Spectrum Estimation: Comparison with Traditional Method2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    During processing of data received by an airborne radar one of the issues is that the typical signal echo from the ground produces a large perturbation. Due to this perturbation it can be difficult to detect targets with low velocity or a low signal-to-noise ratio. Therefore, a filtering process is needed to separate the large perturbation from the target signal. The traditional method include a tapered Fourier transform that operates in parallel with a MTI filter to suppress the main spectral peak in order to produce a smoother spectral output. The difference between a typical signal echo produced from an object in the environment and the signal echo from the ground can be of a magnitude corresponding to more than a 60 dB difference. This thesis presents research of how the multitaper approach can be utilized in concurrence with the minimum variance estimation technique, to produce a spectral estimation that strives for a more effective clutter suppression. A simulation model of the ground clutter was constructed and also a number of simulations for the multitaper, minimum variance estimation technique was made. Compared to the traditional method defined in this thesis, there was a slight improvement of the improvement factor when using the multitaper approach. An analysis of how variations of the multitaper parameters influence the results with respect to minimum detectable velocity and improvement factor have been carried out. The analysis showed that a large number of time samples, a large number of tapers and a narrow bandwidth provided the best result. The analysis is based on a full factorial simulation that provides insight of how to choose the DPSS parameters if the method is to be implemented in a real radar system.

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  • 145.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kyusakov, Rumen
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    An internet of things approach for intelligent monitoring of conveyor belt rollers2013Ingår i: 10th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies 2013, CM 2013 and MFPT 2013, 2013, Vol. 2, s. 1096-1104Konferensbidrag (Refereegranskat)
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  • 146.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lundberg, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Time synchronous bluetooth sensor networks2006Ingår i: IEEE Consumer Communications and Networking Conference: CCNC 2006, Piscataway, NJ: IEEE Communications Society, 2006, s. 336-340Konferensbidrag (Refereegranskat)
    Abstract [en]

    Bluetooth-equipped wireless sensor nodes can be quickly integrated in small home networks. These networks can be utilized e.g. for surveillance, home monitoring and automation. Accurate time is an important factor for time-stamping of sensor data, encryption/authentication and it can also to used to implement time synchronous schemes for low power radio communication. We argue that IP-based time synchronization, such as various flavors of the NTP protocol, can be used with Bluetooth networks. This in combination with an activation schedule allows an efficient trade-off between energy consumption and communication delay, and provides easy integration with available infrastructure. The proposed approach in this paper is well suited for smaller wireless home networks, typically singlehop networks with access points that are always available. Our approach is verified by experiments performed on a COTS-based platform using Bluetooth.

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  • 147. Engberg, Krister
    et al.
    Snällfot, Stefan
    Holmgren, Jonas
    Mätning av hudens ytprofil med hjälp av fokuserat ultraljud.1989Studentarbete övrigt, 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Bakgrunden till detta examensarbete var ett behov av en mätutrustning som klarar av att registrera ett parti av hudens ytprofil.En sådan utrustning kan vara till hjälp för att bedöma sjukdomsutvecklingen hos diabetespatienter med kärlförändringar. Syftet med arbetet har varit att bygga upp och utveckla ett system som mäter ytprofilen hos hud med hjälp av fokuserat ultraljud.

    Det utvecklade systemet fungerar på följande sätt: En ultraljudsgivare monteras på ett koordinatbord och flyttas med precisa steg över det hudområde som skall undersökas. De mot huden reflekterade ljudpulserna mäts med hjälp av ett oscilloskop, vilket sänder kurvdata i heltalsform via en instrumentbuss till en persondator. I datorn skattas ankomsttiden för ljudpulsens eko och höjddata beräknas. De olika metoder för ankomsttidsskattning som undersökts är flank, envelopp och korrelation. Av dessa tre föll valet på korrelation på grund av dess okänslighet för brus och höga mätnoggrannhet.

    Genom mätning av 1000 punkter på en jämn, plan yta erhölls ett mått på standardavvikelsen, detta blev mindre än 0.013 mm för varje mätpunkt. Mättiden för varje punkt är ca 15 sekunder.

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  • 148.
    Eriksson, Håkan B.
    Luleå tekniska universitet.
    Digital block transmission and time-of-flight estimation: receiver design and performance analysis1995Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis is concerned with signal processing aspects of digital block transmission and time-of-flight estimation. Receivers are derived and analysed based on the assumption that the received signals have been corrupted with additive Gaussian noise and linear distortion. A general framework is presented for lower bounding the performance of receivers for digital transmission through linear channels with additive Gaussian noise and intersymbol interference. Building on Forney's concept of the genie, a genie-aided detector based on a stochastic description of the side information is introduced. This statistical description makes the lower bounding a transparent application of Bayesian detection theory. A representation for the minimum bit-error probability receiver is derived using a geometric theory of digital transmission of finite sequences of binary, antipodally, modulated symbols. Assuming that all data sequences are equally probable and transmitted through a linear channel with additive Gaussian noise and intersymbol interference, two properties of the minimum bit-error probability receiver are shown: (1) Asymptotically, as the signal-to-noise ratio (SNR) goes to infinity, the decision regions of the minimum bit-error probability receiver become identical to the decision regions of the maximum likelihood sequence detector; (2) Asymptotically, as the SNR goes to zero, the decision regions of the minimum bit-error probability receiver become identical to the decision regions of the whitened matched filter detector. This confirms the well-known result that the maximum likelihood sequence detector attains minimum bit-error probability for asymptotically high SNR and equally probable sequences. A fast detector of binary, antipodally modulated data that has been corrupted by additive Gaussian noise and intersymbol interference is presented. This detector will make the same decisions as a maximum likelihood sequence detector on scattered bits in a transmitted sequence. It is simple in structure, consisting of a whitened matched filter, two variable thresholds for each bit to be detected and an algorithm to calculate the thresholds. The thresholds are dependent on the received signal and are calculated using an iterative method. Simulation results demonstrate that the probability of bit-error for a decision-feedback equalizer is decreased if this detector is used as a pre-processor. It is also demonstrated that the performance of linear equalizers can be improved substantially. A method for modelling linear distortion of narrowband pulses for the purpose of timeof-flight (TOF) estimation is introduced. This modelling method is based on a known narrowband reference signal being transmitted through an unknown linear and time-invariant system with additive Gaussian noise. The system is modelled in the frequency domain with an M - 1th order complex polynomial around the centre frequency of the reference signal. This enables the output of the system to be modelled as a linear combination of 2M orthonormal base signals. A TOF estimator for this model, based on the criterion of maximum likelihood, is derived. The resulting receiver can be seen as an extension, or generalization, of the cross-correlation, or "matched filter", estimator. The receiver is found to be more robust against unknown linear pulse shape distortion than the crosscorrelation receiver, giving less biased TOF estimates. Also, bias versus noise sensitivity can be controlled by model order selection.

  • 149.
    Eriksson, Håkan B.
    Luleå tekniska universitet.
    Modelling of waveform deformation and time-of-flight estimation1993Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 150.
    Eriksson, Håkan B.
    et al.
    Högskolan i Karlskrona/Ronneby.
    Börjesson, Per-Ola
    Luleå tekniska universitet.
    Holmer, Nils-Gunnar
    Lunds universitet.
    Modelling of waveform deformation and time-of-flight estimation, with application to the ultrasonic pulse-echo method1992Ingår i: International Symposium on Signal Processing and Its Applications: proceedings, August 16-21, 1992, ANA Hotal, Gold Coast, Queensland, Australia / [ed] D. Gray, Edgecliff, N.S.W, 1992, s. 188-191Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we address the problem of estimating the time-of-flight of ultrasonic pulse-echo signals. The shape of the received waveform is modelled by a linear combination of bass signals. A method for obtaining these base signals Is presented. The method presumes that the excitation signal is narrowbanded in the frequency domain

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