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Rönnow, D., Björsell, N. & Laporte-Fauret, B. (2017). Determination of elongation of electrically smallobjects in building structures by polarimetric synthetic aperture radar. In: I2MTC 2017 - 2017 IEEE International Instrumentation and Measurement Technology Conference: Proceedings. Paper presented at International instrumentation and Measurement Technology Conference (I2MTC 2017), 23-25 May 2017, Torino, Italy (pp. 1520-1524). Torino: IEEE, Article ID 7969898.
Open this publication in new window or tab >>Determination of elongation of electrically smallobjects in building structures by polarimetric synthetic aperture radar
2017 (English)In: I2MTC 2017 - 2017 IEEE International Instrumentation and Measurement Technology Conference: Proceedings, Torino: IEEE, 2017, p. 1520-1524, article id 7969898Conference paper, Published paper (Refereed)
Abstract [en]

Short range synthetic aperture radar (SAR) wasused to study electrically small objects. A metallic rod and a metallic sphere could not be separated in the SAR images. Polarimetric SAR images were analyzed and images corresponding to different antenna orientations were obtained by applying rotation matrices to radar data. The target intensity varied with the rotation angle. Elongation and orientation of the objects could be determined from the ratio of minimum andmaximum intensity. Upper and lower limits for measurable elongation depend on measurement errors.

Place, publisher, year, edition, pages
Torino: IEEE, 2017
Keywords
Polarimetry, Synthetic aperture radar
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-24112 (URN)10.1109/I2MTC.2017.7969898 (DOI)000431839600268 ()2-s2.0-85026738669 (Scopus ID)978-1-5090-3596-0 (ISBN)
Conference
International instrumentation and Measurement Technology Conference (I2MTC 2017), 23-25 May 2017, Torino, Italy
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2018-06-12Bibliographically approved
Hamid, M., Björsell, N. & Slimane, B. S. (2017). Empirical Statistical Model for LTE Downlink Channel Occupancy. Wireless personal communications, 96(1), 855-866
Open this publication in new window or tab >>Empirical Statistical Model for LTE Downlink Channel Occupancy
2017 (English)In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 96, no 1, p. 855-866Article in journal (Refereed) Published
Abstract [en]

This paper develops an empirical statistical channel occupancy model for downlink long-term evolution (LTE) cellular systems. The model is based on statistical distributions mixtures for the holding times of the channels. Moreover, statistical distribution of the time when the channels are free is also considered. The data is obtained through an extensive measurement campaign performed in Stockholm, Sweden. Two types of mixtures are considered, namely, exponential and log-normal distributions to fit the measurement findings. The log-likelihood of both mixtures is used as a quantitative measure of the goodness of fit. Moreover, finding the optimal number of linearly combined distributions using the Akaike information criterion (AIC) is investigated. The results show that good fitting can be obtained by using either exponential or log-normal distributions mixture. Even though, the fitting is done for a representative case with a tempo-spatial consideration, the model is yet applicable in general for LTE and other cellular systems in a wider sense.

Keywords
LTE, Cellular Traffic, Channel Occupancy Model, Exponential Mixture Fitting, Log-normal Mixture Fitting, Akaike Information Criterion (AIC).
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:hig:diva-19029 (URN)10.1007/s11277-017-4205-4 (DOI)000408123600048 ()2-s2.0-85019117692 (Scopus ID)
Available from: 2015-02-03 Created: 2015-02-19 Last updated: 2018-03-13Bibliographically approved
Panigrahi, S. R., Björsell, N. & Bengtsson, M. (2017). Feasibility of Large Antenna Arrays towards Low Latency Ultra Reliable Communication. In: 2017 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY (ICIT): . Paper presented at IEEE International Conference on Industrial Technology (ICIT), March 22-25 2017, Toronto, Canada (pp. 1289-1294). , Article ID 7915549.
Open this publication in new window or tab >>Feasibility of Large Antenna Arrays towards Low Latency Ultra Reliable Communication
2017 (English)In: 2017 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY (ICIT), 2017, p. 1289-1294, article id 7915549Conference paper, Published paper (Refereed)
Abstract [en]

Industrial automation and safety applications demand low latency and ultra reliable communication. Currently deployed wireless communication technologies are mostly developed for non-critical applications and hence, they are not suitable for these kind of applications. On the other hand, cable based communication is widely popular in industries, even though it has limitations towards cost of installment and is susceptible towards mechanical wear and tear. This paper reviews the feasibility of large antenna arrays at the receiver to achieve low latency and ultra reliable communication for up-link scenarios. The suitability of both coherent and non-coherent multiple input multiple output (MIMO) receivers are investigated. Non-coherent MIMO receiver is found to be a promising option as signal to noise power ratio (SNR) is fairly reasonable in achieving the desired reliability. The effect of antenna correlation at the transmitter and at receiver on reliability are also looked into. Its influence on the system performance is very nominal. Moreover, in certain scenarios, antenna correlation at the transmitter gives a significant improvement in system performance. Furthermore, having a single antenna at the sensors is found not to be a limiting factor in achieving the desired performance goal.

Keywords
5G, ultra reliable communication, MIMO diversity, coherent receiver, non-coherent receiver
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-24123 (URN)10.1109/ICIT.2017.7915549 (DOI)000404252400213 ()2-s2.0-85019610344 (Scopus ID)
Conference
IEEE International Conference on Industrial Technology (ICIT), March 22-25 2017, Toronto, Canada
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2018-03-13Bibliographically approved
Björsell, N. & Van Moer, W. (2017). Measuring and Characterizing Nonlinear RF Systems: Faculty Course Development Award 2013. IEEE Instrumentation & Measurement Magazine, 20(4), 45-48
Open this publication in new window or tab >>Measuring and Characterizing Nonlinear RF Systems: Faculty Course Development Award 2013
2017 (English)In: IEEE Instrumentation & Measurement Magazine, ISSN 1094-6969, E-ISSN 1941-0123, Vol. 20, no 4, p. 45-48Article in journal (Refereed) Published
Place, publisher, year, edition, pages
IEEE, 2017
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-25754 (URN)000407462800009 ()
Available from: 2017-12-07 Created: 2017-12-07 Last updated: 2018-03-13Bibliographically approved
Krishnan, R., Björsell, N. & Smith, C. (2017). Segmenting humeral submovements using invariant geometric signatures. In: Bicchi, A., Okamura, A. (Ed.), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (Iros): . Paper presented at 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2017), 24–28 September 2017, Vancouver, Canada (pp. 6951-6958). IEEE, Article ID 8206619.
Open this publication in new window or tab >>Segmenting humeral submovements using invariant geometric signatures
2017 (English)In: 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (Iros) / [ed] Bicchi, A., Okamura, A., IEEE, 2017, p. 6951-6958, article id 8206619Conference paper, Published paper (Refereed)
Abstract [en]

Discrete submovements are the building blocks of any complex movement. When robots collaborate with humans, extraction of such submovements can bevery helpful in applications such as robot-assisted rehabilitation. Our work aims to segment these submovements based on the invariant geometric information embedded in segment kinematics. Moreover, this segmentation is achieved without any explicit kinematic representation.Our work demonstrates the usefulness of this invariant framework in segmenting a variety of humeral movements, which are performed at different speeds across different subjects. Our results indicate that this invariant framework has high computational reliability despite the inherent variability in human motion.

Place, publisher, year, edition, pages
IEEE, 2017
Series
IEEE International Conference on Intelligent Robots and Systems, ISSN 2153-0858
Keywords
Kinematics, Human Movement Understanding, Human-centric Robotics
National Category
Robotics
Identifiers
urn:nbn:se:hig:diva-25214 (URN)10.1109/IROS.2017.8206619 (DOI)000426978206070 ()2-s2.0-85041961221 (Scopus ID)978-1-5386-2682-5 (ISBN)978-1-5386-2681-8 (ISBN)
Conference
2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2017), 24–28 September 2017, Vancouver, Canada
Projects
(AAL Call) AXO-SUIT project
Funder
VINNOVA, AAL 2013-6-042
Available from: 2017-09-12 Created: 2017-09-12 Last updated: 2018-05-31Bibliographically approved
Krishnan, R. & Björsell, N. (2017). SHAPE Algorithm for Approximate Computation of Angular Velocities in Humeral Motion. In: 2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC): . Paper presented at 2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 22-25 May 2017, Torino, Italy (pp. 714-718). IEEE
Open this publication in new window or tab >>SHAPE Algorithm for Approximate Computation of Angular Velocities in Humeral Motion
2017 (English)In: 2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), IEEE, 2017, p. 714-718Conference paper, Published paper (Refereed)
Abstract [en]

Estimating human motion is an area of emerging interest in instrumentation and measurement. Importantly, in such applications the physicality of the solution is paramount. Therefore, our paper proposes the SHAPE algorithm to estimate angular velocities of a moving segment from a cluster of passive markers used in a standard motion capture system known as stereophotogrammetry. We demonstrate the efficacy of our formulation with reference to the well known shape-matching algorithm in computer graphics. It is shown that our method is superior over the shape-matching algorithm.

Place, publisher, year, edition, pages
IEEE, 2017
Keywords
Angular velocity, Shape, Clustering algorithms, Heuristic algorithms, Kinematics, Atmospheric measurements
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-24114 (URN)10.1109/I2MTC.2017.7969776 (DOI)000431839600126 ()2-s2.0-85026782789 (Scopus ID)978-1-5090-3596-0 (ISBN)
Conference
2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 22-25 May 2017, Torino, Italy
Funder
VINNOVA, AAL 2013-6-042
Note

This preprint is for personal use only.

Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2018-06-12Bibliographically approved
Hamid, M., Björsell, N. & Slimane, B. (2016). Energy and Eigenvalue-Based Combined Fully-Blind Self-Adapted Spectrum Sensing Algorithm. IEEE Transactions on Vehicular Technology, 65(2), 630-642
Open this publication in new window or tab >>Energy and Eigenvalue-Based Combined Fully-Blind Self-Adapted Spectrum Sensing Algorithm
2016 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 65, no 2, p. 630-642Article in journal (Refereed) Published
Abstract [en]

In this paper, a comparison between energy and maximum-minimum eigenvalue detectors is performed. The comparison has been made concerning the sensing complexity and the sensing accuracy in terms of the receiver operating characteristics curves. The impact of the signal bandwidth compared to the observation bandwidth is studied for each detector. For the energy detector, the probability of detection increases monotonically with the increase of the signal bandwidth. For the maximum-minimum eigenvalue detector, an optimal value of the ratio between the signal bandwidth and the observation bandwidth is found to be 0.5 when reasonable values of the system dimensionality are used. Based on the comparison findings, a combined two-stage detector is proposed. The combined detector performance is evaluated based on simulations and measurements. The combined detector achieves better sensing accuracy than the two individual detectors with a complexity lies in between the two individual complexities. The combined detector is fully-blind and self-adapted as the maximum-minimum eigenvalue detector estimates the noise and feeds it back to the energy detector. The performance of the noise estimation process is evaluated in terms of the normalized mean square error.

Keywords
Blind sensing, Energy detector, Maximum-minimum eigenvalue detector, Multi-stage sensing, Noise estimation
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-18957 (URN)10.1109/TVT.2015.2401132 (DOI)000370754000012 ()2-s2.0-84962176492 (Scopus ID)
Available from: 2015-02-10 Created: 2015-02-10 Last updated: 2018-03-13Bibliographically approved
Krishnan, R., Björsell, N. & Smith, C. (2016). How do we plan movements?: A geometric answer. In: School and symposium on advanced neurorehabilitation (SSNR2016): Proceedings. Paper presented at School and symposium on advanced neurorehabilitation (SSNR2016), 6-10 June 2016, Baiona, Spain (pp. 16-17).
Open this publication in new window or tab >>How do we plan movements?: A geometric answer
2016 (English)In: School and symposium on advanced neurorehabilitation (SSNR2016): Proceedings, 2016, , p. 2p. 16-17Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Human movement is essentially a complex phenomenon. When humans work closely with robots, understanding human motion using robot’s sensors is a very challenging problem. This is partially due to the lack of proper consensus among researchers on which representation to use in such situations. This extended abstract presents a novel kinematic framework to study human intention using hybrid twists. Thisis important as the functional aspects of the human shoulder are evaluated using the information embedded in thoraco-humeral kinematics. We successfully demonstrate that our approach is singularity free. We also demonstrate that how the twis tparameters vary according to the movement being performed.

Publisher
p. 2
National Category
Robotics
Identifiers
urn:nbn:se:hig:diva-22702 (URN)
Conference
School and symposium on advanced neurorehabilitation (SSNR2016), 6-10 June 2016, Baiona, Spain
Projects
VINNOVA, AAL 2013-6-042
Funder
VINNOVA, AAL 2013-6-042
Available from: 2016-11-07 Created: 2016-11-07 Last updated: 2018-03-13Bibliographically approved
Krishnan, R., Björsell, N. & Smith, C. (2016). Human shoulder functional kinematics: Are we ready for the high-reliability computational challenge?. In: : . Paper presented at 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)- Human Movement Understanding and Robotics, 9-14 October 2016, Daejeon, South Korea.
Open this publication in new window or tab >>Human shoulder functional kinematics: Are we ready for the high-reliability computational challenge?
2016 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

In  this  preview  talk,  I  will  present  a  short  summary  of  our  ongoing  work  related  to  human shoulder functional kinematics.  Robot-assisted rehabilitation needs functional understanding of human kinematics in design, operation and evaluation of this technology. Human shoulder is an important  functional  joint  that  enables  fine  motor  skills  for  human  upper  arm  manipulation. Due  to  several  mathematical  and  practical  challenges,  the  shoulder  kinematics  is  often oversimplified. Moreover, there is a lack of agreement among different research communities on  the  suitable  kinematic  representation  when  connecting  humans  to  robots.  Currently,  it  is expected  that  this  computational  structure  used  in  such  applications  have  high-reliability. Therefore,  we  pose  the  question:  Are  we  ready  for  the  high-reliability  computational challenge?

National Category
Robotics
Identifiers
urn:nbn:se:hig:diva-24118 (URN)
Conference
2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)- Human Movement Understanding and Robotics, 9-14 October 2016, Daejeon, South Korea
Funder
VINNOVA, AAL 2013-6-042
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2018-03-13Bibliographically approved
Krishnan, R., Björsell, N. & Smith, C. (2016). Invariant Spatial Parametrization of Human Thoracohumeral Kinematics: A Feasibility Study. In: 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS): . Paper presented at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016), 9-14 October 2016, Daejeon, Korea (pp. 4469-4476). IEEE Robotics and Automation Society, Article ID 7759658.
Open this publication in new window or tab >>Invariant Spatial Parametrization of Human Thoracohumeral Kinematics: A Feasibility Study
2016 (English)In: 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE Robotics and Automation Society, 2016, p. 4469-4476, article id 7759658Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we present a novel kinematic framework using hybrid twists, that has the potential to improve the reliability of estimated human shoulderkinematics. This is important as the functional aspects ofthe human shoulder are evaluated using the information embedded in thoracohumeral kinematics. We successfully demonstrate in our results, that our approach is invariant of the body-fixed coordinate definition, is singularity free and has high repeatability; thus resulting in a flexible user-specific kinematic tracking not restricted to bony landmarks.

Place, publisher, year, edition, pages
IEEE Robotics and Automation Society, 2016
Keywords
Human movement analysis, Kinematics, Human detection and tracking
National Category
Robotics
Identifiers
urn:nbn:se:hig:diva-22193 (URN)10.1109/IROS.2016.7759658 (DOI)000391921704074 ()27295638 (PubMedID)2-s2.0-85006427957 (Scopus ID)978-1-5090-3762-9 (ISBN)
Conference
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016), 9-14 October 2016, Daejeon, Korea
Funder
VINNOVA, AAL 2013-6-042
Note

Accepted paper. This preprint is for personal use only.

(AAL Call 6) AXO-SUIT project

Available from: 2016-08-07 Created: 2016-08-07 Last updated: 2018-03-13Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5429-7223

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