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  • 301.
    Pomareda, Victor
    et al.
    Intelligent Signal Processing, Department of Electronics, University of Barcelona, Barcelona, Spain.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Abdul Khaliq, Ali
    Örebro University, School of Science and Technology.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Marco, Santiago
    Intelligent Signal Processing, Department of Electronics, University of Barcelona, Barcelona, Spain.
    Chemical source localization in real environments integrating chemical concentrations in a probabilistic plume mapping approach2013In: Proceedings of the 15th International Symposium on Olfaction and Electronic Nose (ISOEN 2013), 2013Conference paper (Refereed)
    Abstract [en]

    Chemical plume source localization algorithms can be classified either as reactive plume tracking or gas distribution mapping approaches. Here, we focus on gas distribution mapping methods where the robot does not need to track the plume to find the source and can be used for other tasks. Probabilistic mapping approaches have been previously applied to real-world data successfully; e.g., in the approach proposed by Pang and Farrell. Instead of the quasi-continuous gas measurement values, this algorithm considers events (detections and non-detections) based on whether the sensor response is above or below a threshold to update recursively a source probability grid map; thus, discarding important information. We developed an extension of this event-based approach, integrating chemical concentrations directly instead of binary information. In this work, both algorithms are compared using real-world data obtained from a photo-ionization detector (PID), a non-selective gas sensor, and an anemometer in real environments. We validate simulation results and demonstrate that the concentration-based approach is more accurate in terms of a higher probability at the ground truth source location, a smaller distance between the probability maximum and the source location, and a more peaked probability distribution, measured in terms of the overall entropy.

  • 302.
    Potenza, Andre
    et al.
    Örebro University, School of Science and Technology.
    Kiselev, Andrey
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Towards Sliding Autonomy in Mobile Robotic Telepresence: A Position Paper2017Conference paper (Refereed)
    Abstract [en]

    Sliding autonomy is used in teleoperation to adjusting a robot's level of local autonomy to match the user's needs. We claim that sliding autonomy can also improve mobile robotic telepresence, but we argue that existing approaches cannot be adopted to this domain without adequate modifications. We address in particular the question of how the need for autonomy, and its appropriate degree, can be inferred from measurable information.

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    fulltext
  • 303.
    Rahayem, Mohamed
    et al.
    Örebro University, School of Science and Technology.
    Werghi, Naoufel
    Electrical and Computer Engineering Department, Khalifa University, Sharjah, United Arab Emirates.
    Kjellander, Johan
    Örebro University, School of Science and Technology.
    Best ellipse and cylinder parameters estimation from laser profile scan sections2012In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 50, no 9, p. 1242-1259Article in journal (Refereed)
    Abstract [en]

    Industrial applications like robot-aided welding, automated inspection, and 3D measurements require 3D points to be captured from the surfaces of objects and processed to calculate the information-of-interest. The lack of research focused on fitting ellipses to 3D laser profile data, and the intrinsic features that distinguish it from 2D digital images, motivated us to conduct a comparative study involving the most popular ellipse-fitting methods. After describing our laser profile scanning system, and a survey of ellipse-fitting methods, we compare, using extensive experiments performed with synthetic and real data, the fitting algorithms in terms of stability and accuracy with respect to a variety of factors. The estimate obtained with the best method is used to initialize a robust non-linear iterative ellipse fitting method. Finally, we describe a novel method for the construction of cylindrical surfaces from estimated elliptical sections.

  • 304.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sensing the Environment: a Perceptual and Psychosocial Analysis of Events in the Surroundings from a Handicap Perspective. Medicinteknikdagarna Örebro2007Conference paper (Refereed)
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  • 305.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sensing the Environment: a Perceptual and Psychosocial Analysis of Events in the Surroundings from a Handicap Perspective. Missisauga2003Conference paper (Other academic)
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  • 306.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sensing the Environment: a Perceptual and Psychosocial Analysis of Events in the Surroundings from a Handicap Perspective. Perth2007Conference paper (Other academic)
    Download (pdf)
    sammanfattning
  • 307.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sensing the environment: development of monitoring aids for persons with profound deafness or deafblindness2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Earlier studies of persons with deafness (D) and/or deafblindness (DB) have primarily focused on the mobility and communication problems. The purpose of the present study was to develop technology for monitoring aids to improve the ability of persons with D and/or DB to detect, identify, and perceive direction of events that produce sounds in their surroundings.

    The purpose was achieved stepwise in four studies. In Study I, the focus was on hearing aids for persons with residual low frequency hearing. In Study II-IV, the focus was on vibratory aids for persons with total D.

    In Study I, six signal processing algorithms (calculation methods) based on two principles, transposition and modulation, were developed and evaluated regarding auditory identification of environmental sounds. Twenty persons with normal hearing listened to 45 environmental sounds processed with the six different algorithms and identified them in three experiments. In Exp. 1, the sounds were unknown and the subjects had to identify them freely. In Exp. 2 and 3, the sounds were known and the subjects had to identify them by choosing one of 45 sounds. The transposing algorithms showed better results (median value in Exp. 3, 64%-69%) than the modulating algorithms (40%-52%) did, and they were good candidates for implementing in a hearing aid for persons with residual low frequency hearing.

    In Study II, eight algorithms were developed based on three principles, transposition, modulation, and filtration – in addition to No Processing as reference, and evaluated for vibratory identification of environmental sounds. The transposing algorithms and the modulating algorithms were also adapted to the vibratory thresholds of the skin. Nineteen persons with profound D tested the algorithms using a stationary, wideband vibrator and identified them by choosing one of 10 randomly selected from the list of 45 sounds. One transposing algorithm and two modulating algorithms showed better (p<0.05) scores than did the No Processing method. Two transposing and three modulating algorithms showed better (p<0.05) scores than did the filtering algorithm. Adaptation to the vibratory thresholds of the skin did not improve the vibratory identification results.

    In Study III, the two transposing algorithms and the three modulating algorithms with the best identification scores in Study II, plus their adapted alternative, were evaluated in a laboratory study. Five persons from Study II with profound D tested the algorithms using a portable narrowband vibrator and identified the sounds by choosing one of 45 sounds in three experiments (Exp. 1, 2, and 3). In Exp. 1, the sounds were pre-processed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time. Five of the algorithms had acceptable results (27%-41%) in the three experiments and constitute candidates for a miniaturized vibratory aid (VA). The algorithms had the same rank order in both tests in the acoustic room (Exp. 2, and 3), and the noise did not worsen the identification results.

    In Study IV, the portable vibrotactile monitoring aid (with stationary processor) for detection, identification and directional perception of environmental sounds was evaluated in a field study. The same five persons with profound D as in Study III tested the aid using a randomly chosen algorithm, drawn from the five with the best results in Study III, in a home and in a traffic environment. The persons identified 12 events at home and five events in a traffic environment when they were inexperienced (the events were unknown) and later when they were experienced (the events were known). The VA consistently improved the ability with regard to detection, identification and directional perception of environmental sounds for all five persons.

    It is concluded that the selected algorithms improve the ability to detect, and identify sound emitting events. In future, the algorithms will be implemented in a low frequency hearing aid for persons with low frequency residual hearing or in a fully portable vibratory monitoring aid, for persons with profound D or DB to improve their ability to sense the environment.

    List of papers
    1. Auditive identification of signal-processed environmental sounds: monitoring the environment
    Open this publication in new window or tab >>Auditive identification of signal-processed environmental sounds: monitoring the environment
    2008 (English)In: International Journal of Audiology, ISSN 1499-2027, E-ISSN 1708-8186, Vol. 47, no 12, p. 724-736Article in journal (Refereed) Published
    Abstract [en]

    The goal of the present study was to compare six transposing signal-processing algorithms based on different principles (Fourier-based and modulation based), and to choose the algorithm that best enables identification of environmental sounds, i.e. improves the ability to monitor events in the surroundings. Ten children (12-15 years) and 10 adults (21-33 years) with normal hearing listened to 45 representative environmental (events) sounds processed using the six algorithms, and identified them in three different listening experiments involving an increasing degree of experience. The sounds were selected based on their importance for normal hearing and deaf-blind subjects. Results showed that the algorithm based on transposition of 1/3 octaves (fixed frequencies) with large bandwidth was better (p<0.015) than algorithms based on modulation. There was also a significant effect of experience (p<0.001). Adults were significantly (p<0.05) better than children for two algorithms. No clear gender difference was observed. It is concluded that the algorithm based on transposition with large bandwidth and fixed frequencies is the most promising for development of hearing aids to monitor environmental sounds.

    Place, publisher, year, edition, pages
    London: Taylor & Francis, 2008
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering Medical Engineering
    Research subject
    Medicine; Electrical Engineering
    Identifiers
    urn:nbn:se:oru:diva-6995 (URN)10.1080/14992020802289776 (DOI)19085397 (PubMedID)
    Available from: 2009-05-28 Created: 2009-05-28 Last updated: 2018-10-31Bibliographically approved
    2. Vibrotactile identification of signal-processed sounds from environmental events
    Open this publication in new window or tab >>Vibrotactile identification of signal-processed sounds from environmental events
    2009 (English)In: Journal of rehabilitation research and development, ISSN 0748-7711, E-ISSN 1938-1352, Vol. 46, no 8, p. 1021-1036Article in journal (Refereed) Published
    Abstract [en]

    Objective: To compare three different signal-processing principles (eight basic algorithms), transposing, modulating and filtering, and to find the principle(s)/al­go­rithm(s) that result in the best tactile identification of environmental sounds.

    Subjects: Nineteen volunteers (9F/10M), deaf or profoundly hearing impaired, between 18-50 yr. 

    Method: Sounds produced by 45 representative en­vi­ron­men­tal events were processed using the different al­go­rithms and presented to subjects as tactile stimuli using a wide-band stationary vibrator. Eight algorithms based on the three principles (one un­pro­cessed, used as reference) were compared. The subjects iden­ti­fied the sti­mu­li by choo­sing one among ten alter­na­tives drawn from the 45 events. 

    Result and conclusion: Algorithm and subject were significant (RM-ANOVA, p<0.001) factors affecting the results. There were also large differences between individuals regarding which algorithm was best. The test-retest variability was small (Mean±95%CI: 8±3 percentage units), and no correlation between identification score and individual vibratory thresholds was found. One transposing al­go­rithm and two mo­du­lating al­go­rithms led to significantly (p<0.05) better results than did the unprocessed signals. Thus, the two principles of transposing and modulating were appropriate, whereas filtering was unsuccessful. In future work, the two transposing algorithms and the modulating algorithms will be used in tests with a portable vibra­tor for the deafblind.

    Keywords
    Deafblind, Environmental sound, Identification, Monitoring, Perception, Tactile, Transposing, Vibration
    National Category
    Signal Processing
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-8126 (URN)10.1682/JRRD.2008.11.0150 (DOI)000274171000005 ()20157859 (PubMedID)2-s2.0-75749141318 (Scopus ID)
    Projects
    Sensing the environment
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-10-31Bibliographically approved
    3. Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: a laboratory study
    Open this publication in new window or tab >>Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: a laboratory study
    2009 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To evaluate different signal-processing algorithms for tactile identification of environmental sounds in a monitoring aid for the deafblind.

    Subjects: Two men and three women, sensorineurally deaf or profoundly hearing impaired with experience of vibratory experiments, age 22-36 years.

    Method: A closed set of 45 representative environmental sounds were processed using two transposing (TRHA, TR1/3) and three modulating algorithms (AM, AMFM, AMMC) and presented as tactile stimuli using a portable vibrator in three experiments. The algorithms TRHA, TR1/3, AMFM and AMMC had two alternatives (with and without adaption to vibratory thresholds). In Exp. 1, the sounds were preprocessed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time.

    Results: In Exp. 1, Algorithm AMFM and AMFM(A) consistently had the lowest identification scores, and were thus excluded in Exp. 2 and 3. TRHA, AM, AMMC, and AMMC(A) showed comparable identification scores (30%-42%) and the addition of noise did not deteriorate the performance.

    Conclusion: Algorithm TRHA, AM, AMMC, and AMMC(A) showed good performance in all three experiments and were robust in noise; they can therefore be used in further testing in real environments.

    Keywords
    Environmental sound, Identification, Narrow-band, Tactile perception, Transposing, Vibration, Vibrator
    National Category
    Signal Processing Engineering and Technology Computer and Information Sciences
    Research subject
    Signal Processing
    Identifiers
    urn:nbn:se:oru:diva-8129 (URN)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-01-13Bibliographically approved
    4. Vibrotactile detection, identification and directional perception of signal-processed sounds from environmental events: a pilot field evaluation in five cases
    Open this publication in new window or tab >>Vibrotactile detection, identification and directional perception of signal-processed sounds from environmental events: a pilot field evaluation in five cases
    Show others...
    2009 (English)In: Iranian Rehabilitation Journal, ISSN 1735-3602, Vol. 6, no 7-8, p. 89-107Article in journal (Refereed) Published
    Abstract [en]

    Objective: Conducting field tests of a vibrotactile aid for deaf/deafblind persons for detection, identification and directional perception of environmental sounds.

    Method: Five deaf (3F/2M, 22–36 years) individuals tested the aid separately in a home environment (kitchen) and in a traffic environment. Their eyes were blindfolded and they wore a headband and holding a vibrator for sound identification. In the headband, three microphones were mounted and two vibrators for signalling direction of the sound source. The sounds originated from events typical for the home environment and traffic. The subjects were inexperienced (events unknown) and experienced (events known). They identified the events in a home and traffic environment, but perceived sound source direction only in traffic.

    Results: The detection scores were higher than 98% both in the home and in the traffic environment. In the home environment, identification scores varied between 25%-58% when the subjects were inexperienced and between 33%-83% when they were experienced. In traffic, identification scores varied between 20%-40% when the subjects were inexperienced and between 22%-56% when they were experienced. The directional perception scores varied between 30%-60% when inexperienced and between 61%-83% when experienced.

    Conclusion: The vibratory aid consistently improved all participants’ detection, identification and directional perception ability.

    Place, publisher, year, edition, pages
    Tehran: University of social welfare and rehabilitation sciences Evin, 2009
    Keywords
    Deaf, Deafblind, Directional perception, Environmental sound, Tactile perception
    National Category
    Signal Processing Other Health Sciences
    Research subject
    Electronics; Disability Science
    Identifiers
    urn:nbn:se:oru:diva-8131 (URN)
    Projects
    Sensing the environment
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-10-18Bibliographically approved
    Download full text (pdf)
    FULLTEXT01
  • 308.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sinnena, konst och vetenskap: att känna omvärlden2007Conference paper (Other academic)
    Download (pdf)
    sammanfattning
  • 309.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: a laboratory study2009Manuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To evaluate different signal-processing algorithms for tactile identification of environmental sounds in a monitoring aid for the deafblind.

    Subjects: Two men and three women, sensorineurally deaf or profoundly hearing impaired with experience of vibratory experiments, age 22-36 years.

    Method: A closed set of 45 representative environmental sounds were processed using two transposing (TRHA, TR1/3) and three modulating algorithms (AM, AMFM, AMMC) and presented as tactile stimuli using a portable vibrator in three experiments. The algorithms TRHA, TR1/3, AMFM and AMMC had two alternatives (with and without adaption to vibratory thresholds). In Exp. 1, the sounds were preprocessed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time.

    Results: In Exp. 1, Algorithm AMFM and AMFM(A) consistently had the lowest identification scores, and were thus excluded in Exp. 2 and 3. TRHA, AM, AMMC, and AMMC(A) showed comparable identification scores (30%-42%) and the addition of noise did not deteriorate the performance.

    Conclusion: Algorithm TRHA, AM, AMMC, and AMMC(A) showed good performance in all three experiments and were robust in noise; they can therefore be used in further testing in real environments.

  • 310.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Science and Technology.
    Anderzén-Carlsson, Agneta
    Örebro University, Department of Health Sciences.
    Neovius, Lennart
    Saven Hitech AB.
    Johansson, Camilla
    Audiologiska forskningscentrum.
    Borg, Erik
    Audiologiska forskningscentrum, USÖ.
    Vibrotactile detection, identification and directional perception of signal-processed sounds from environmental events: a pilot field evaluation in five cases2009In: Iranian Rehabilitation Journal, ISSN 1735-3602, Vol. 6, no 7-8, p. 89-107Article in journal (Refereed)
    Abstract [en]

    Objective: Conducting field tests of a vibrotactile aid for deaf/deafblind persons for detection, identification and directional perception of environmental sounds.

    Method: Five deaf (3F/2M, 22–36 years) individuals tested the aid separately in a home environment (kitchen) and in a traffic environment. Their eyes were blindfolded and they wore a headband and holding a vibrator for sound identification. In the headband, three microphones were mounted and two vibrators for signalling direction of the sound source. The sounds originated from events typical for the home environment and traffic. The subjects were inexperienced (events unknown) and experienced (events known). They identified the events in a home and traffic environment, but perceived sound source direction only in traffic.

    Results: The detection scores were higher than 98% both in the home and in the traffic environment. In the home environment, identification scores varied between 25%-58% when the subjects were inexperienced and between 33%-83% when they were experienced. In traffic, identification scores varied between 20%-40% when the subjects were inexperienced and between 22%-56% when they were experienced. The directional perception scores varied between 30%-60% when inexperienced and between 61%-83% when experienced.

    Conclusion: The vibratory aid consistently improved all participants’ detection, identification and directional perception ability.

  • 311.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Science and Technology.
    Borg, Erik
    Örebro University, School of Health and Medical Sciences.
    Philipson, Lennart
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Auditive identification of signal-processed environmental sounds: monitoring the environment2008In: International Journal of Audiology, ISSN 1499-2027, E-ISSN 1708-8186, Vol. 47, no 12, p. 724-736Article in journal (Refereed)
    Abstract [en]

    The goal of the present study was to compare six transposing signal-processing algorithms based on different principles (Fourier-based and modulation based), and to choose the algorithm that best enables identification of environmental sounds, i.e. improves the ability to monitor events in the surroundings. Ten children (12-15 years) and 10 adults (21-33 years) with normal hearing listened to 45 representative environmental (events) sounds processed using the six algorithms, and identified them in three different listening experiments involving an increasing degree of experience. The sounds were selected based on their importance for normal hearing and deaf-blind subjects. Results showed that the algorithm based on transposition of 1/3 octaves (fixed frequencies) with large bandwidth was better (p<0.015) than algorithms based on modulation. There was also a significant effect of experience (p<0.001). Adults were significantly (p<0.05) better than children for two algorithms. No clear gender difference was observed. It is concluded that the algorithm based on transposition with large bandwidth and fixed frequencies is the most promising for development of hearing aids to monitor environmental sounds.

  • 312.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Stenström, Ingeborg
    Monitor, a vibrotactile aid for environmental perception: a field evaluation by four people with severe hearing and vision impairment2013In: Scientific World Journal, ISSN 1537-744X, E-ISSN 1537-744X, no Article ID 206734, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44-54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%-97% and 58%-95% with the directional microphone. The corresponding values in traffic were 29%-100% and 65%-100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds.

  • 313.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital, Örebro, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Akner-Koler, Cheryl
    University Collage of Arts (Konstfack), Stockholm, Sweden.
    Borg, Erik
    Örebro University Hospital, Örebro, Sweden.
    Haptic Technical Aids for EnvironmentalPerception, Time Perception and Mobility (in a Riding Arena) for Persons with Deafblindness2014In: HAPTICS: NEUROSCIENCE, DEVICES, MODELING, AND APPLICATIONS, PT II, Springer Berlin/Heidelberg, 2014, Vol. 8619, p. 488-490Conference paper (Other academic)
    Abstract [en]

    This demonstration presents three vibrotactile aids to support personswith deafblindness. One aid, Monitor, consists of a microphone that detectssounds from events which are then processed as a signal that is adapted to thesensitivity range of the skin. The signal is sent as vibrations to the user withdeafblindness, who can interpret the pattern of the vibrations in order to identifythe type and position of the event/source that produced the sounds. Another aid,Distime, uses a smart phone app that informs the user with cognitive impairmentand deafblindness about a planned activity through; audio, visual or tactileinteraction that is adapted to the abilities of each individual. The last aid, Ready-ride, uses two smart phones and up to 11 vibrators that help the horse back riderwith deafblindness to communicate with the instructor from a distance viavibrators placed on different parts of the riders body e.g. wrist, thigh, back, ankle.

  • 314.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Akner-Koler, Cheryl
    University College of Arts, Crafts and Design in Sweden (Konstfack), Stockholm,Sweden .
    Borg, Erik
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Monitor: a vibrotactile aid to improve environmental perception of persons with severe hearing impairment/deafblindness2012In: TeMA Hörsel, 2012, 2012Conference paper (Other academic)
  • 315.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Erik, Borg
    Audilogiska forskningscentrum.
    Vibrotactile identification of signal-processed sounds from environmental events2009In: Journal of rehabilitation research and development, ISSN 0748-7711, E-ISSN 1938-1352, Vol. 46, no 8, p. 1021-1036Article in journal (Refereed)
    Abstract [en]

    Objective: To compare three different signal-processing principles (eight basic algorithms), transposing, modulating and filtering, and to find the principle(s)/al­go­rithm(s) that result in the best tactile identification of environmental sounds.

    Subjects: Nineteen volunteers (9F/10M), deaf or profoundly hearing impaired, between 18-50 yr. 

    Method: Sounds produced by 45 representative en­vi­ron­men­tal events were processed using the different al­go­rithms and presented to subjects as tactile stimuli using a wide-band stationary vibrator. Eight algorithms based on the three principles (one un­pro­cessed, used as reference) were compared. The subjects iden­ti­fied the sti­mu­li by choo­sing one among ten alter­na­tives drawn from the 45 events. 

    Result and conclusion: Algorithm and subject were significant (RM-ANOVA, p<0.001) factors affecting the results. There were also large differences between individuals regarding which algorithm was best. The test-retest variability was small (Mean±95%CI: 8±3 percentage units), and no correlation between identification score and individual vibratory thresholds was found. One transposing al­go­rithm and two mo­du­lating al­go­rithms led to significantly (p<0.05) better results than did the unprocessed signals. Thus, the two principles of transposing and modulating were appropriate, whereas filtering was unsuccessful. In future work, the two transposing algorithms and the modulating algorithms will be used in tests with a portable vibra­tor for the deafblind.

  • 316.
    Rashid, Jayedur
    et al.
    Örebro University, School of Science and Technology.
    Broxvall, Mathias
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    A middleware to integrate robots, simple devices and everyday objects into an ambient ecology2012In: Pervasive and Mobile Computing, ISSN 1574-1192, E-ISSN 1873-1589, Vol. 8, no 4, p. 522-541Article in journal (Refereed)
    Abstract [en]

    The fields of ambient intelligence, distributed robotics and wireless sensor networks are converging toward a common vision, in which ubiquitous sensing and acting devices cooperate to provide useful services in the home. These devices can range from sophisticated mobile robots to simple sensor nodes and even simpler tagged everyday objects. In this vision, a milkbox left on the table after the user has left the home could ask the service of a mobile robot to be placed back in the refrigerator. A missing ingredient to realize this vision is a mechanism that enables the communication and interoperation among such highly heterogeneous entities. In this paper, we propose such a mechanism in the form of a middleware able to integrate robots, tiny devices and augmented everyday objects into one and the same system. The key moves to cope with heterogeneity are: the definition of a tiny, compatible version of the middleware, that can run on small devices; and the concept of object proxy, used to make everyday object accessible within the middleware. We describe the concepts and implementation of our middleware, and show a number of experiments that illustrate its performance.

  • 317.
    Razvarz, Sina
    et al.
    Departamento de Control Automático, CINVESTAV-IPN (National Polytechnic Institute), Mexico City, Mexico.
    Jafari, Raheleh
    Department of Information and Communication Technology, Agder University College, Grimstad, Norway.
    Gegov, Alexander
    School of Computing, University of Portsmouth, Portsmouth, United States.
    Yu, Wen
    Departamento de Control Automático, CINVESTAV-IPN (National Polytechnic Institute), Mexico City, Mexico.
    Paul, Satyam
    Departamento de Control Automático, CINVESTAV-IPN (National Polytechnic Institute), Mexico City, Mexico.
    Neural Network Approach to Solving Fully Fuzzy Nonlinear Systems2018In: Fuzzy Modeling and Control: Methods, Applications and Research / [ed] Terrell Harvey & Dallas Mullins, Nova Science Publishers, Inc., 2018, p. 46-68Chapter in book (Refereed)
    Abstract [en]

    The value of fuzzy designs improves whenever a system cannot be validated in precise mathematical terminologies. In this book chapter, two types of neural networks are applied to obtain the approximate solutions of the fully fuzzy nonlinear system (FFNS). For obtaining the approximate solutions, a superior gradient descent algorithmis proposed in order to train the neural networks. Several examples are illustrated to disclosehigh precision as well as the effectiveness of the proposed methods. The MATLAB environment is utilized to generate the simulations.

  • 318.
    Reggente, Matteo
    et al.
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Three-dimensional statistical gas distribution mapping in an uncontrolled indoor environment2009In: Olfaction and electronic nose / [ed] Matteo Pardo, Giorgio Sberveglieri, 2009, p. 109-112Conference paper (Refereed)
    Abstract [en]

    In this paper we present a statistical method to build three-dimensional gas distribution maps (3D-DM). The proposed mapping technique uses kernel extrapolation with a tri-variate Gaussian kernel that models the likelihood that a reading represents the concentration distribution at a distant location in the three dimensions. The method is evaluated using a mobile robot equipped with three "e-noses" mounted at different heights. Initial experiments in an uncontrolled indoor environment are presented and evaluated with respect to the ability of the 3D map, computed from the lower and upper nose, to predict the map from the middle nose.

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    FULLTEXT01
  • 319.
    Reggente, Matteo
    et al.
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Using local wind information for gas distribution mapping in outdoor environments with a mobile robot2009In: 2009 IEEE SENSORS, VOLS 1-3, NEW YORK: IEEE conference proceedings, 2009, p. 1715-1720Chapter in book (Other academic)
    Abstract [en]

    In this paper we introduce a statistical method to build two-dimensional gas distribution maps (Kernel DM+V/W algorithm). In addition to gas sensor measurements, the proposed method also takes into account wind information by modeling the information content of the gas sensor measurements as a bivariate Gaussian kernel whose shape depends on the measured wind vector. We evaluate the method based on real measurements in an outdoor environment obtained with a mobile robot that was equipped with gas sensors and an ultrasonic anemometer for wind measurements. As a measure of the model quality we compute how well unseen measurements are predicted in terms of the data likelihood. The initial results are encouraging and show a clear improvement of the proposed method compared to the case where wind is not considered.

  • 320.
    Ringdahl, Ola
    et al.
    Umeå University, Umeå, Sweden.
    Kurtser, Polina
    Örebro University, School of Science and Technology.
    Edan, Yael
    Ben-Gurion University of the Negev, Beer Sheva, Israel.
    Performance of RGB-D camera for different object types in greenhouse conditions2019In: 2019 European Conference on Mobile Robots (ECMR) / [ed] Libor Přeučil, Sven Behnke, Miroslav Kulich, IEEE, 2019, p. 1-6Conference paper (Refereed)
    Abstract [en]

    RGB-D cameras play an increasingly important role in localization and autonomous navigation of mobile robots. Reasonably priced commercial RGB-D cameras have recently been developed for operation in greenhouse and outdoor conditions. They can be employed for different agricultural and horticultural operations such as harvesting, weeding, pruning and phenotyping. However, the depth information extracted from the cameras varies significantly between objects and sensing conditions. This paper presents an evaluation protocol applied to a commercially available Fotonic F80 time-of-flight RGB-D camera for eight different object types. A case study of autonomous sweet pepper harvesting was used as an exemplary agricultural task. Each of the objects chosen is a possible item that an autonomous agricultural robot must detect and localize to perform well. A total of 340 rectangular regions of interests (ROI) were marked for the extraction of performance measures of point cloud density, and variability around center of mass, 30-100 ROIs per object type. An additional 570 ROIs were generated (57 manually and 513 replicated) to evaluate the repeatability and accuracy of the point cloud. A statistical analysis was performed to evaluate the significance of differences between object types. The results show that different objects have significantly different point density. Specifically metallic materials and black colored objects had significantly less point density compared to organic and other artificial materials introduced to the scene as expected. The point cloud variability measures showed no significant differences between object types, except for the metallic knife that presented significant outliers in collected measures. The accuracy and repeatability analysis showed that 1-3 cm errors are due to the the difficulty for a human to annotate the exact same area and up to ±4 cm error is due to the sensor not generating the exact same point cloud when sensing a fixed object.

  • 321.
    Rudenko, Andrey
    et al.
    Örebro University, School of Science and Technology. Bosch Corporate Research, Stuttgart, Germany.
    Palmieri, Luigi
    Bosch Corporate Research, Stuttgart, Germany.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Arras, Kai O.
    Bosch Corporate Research, Stuttgart, Germany.
    Human Motion Prediction under Social Grouping Constraints2018In: 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, 2018, p. 3358-3364Conference paper (Refereed)
    Abstract [en]

    Accurate long-term prediction of human motion inpopulated spaces is an important but difficult task for mobile robots and intelligent vehicles. What makes this task challenging is that human motion is influenced by a large variety offactors including the person’s intention, the presence, attributes, actions, social relations and social norms of other surrounding agents, and the geometry and semantics of the environment. In this paper, we consider the problem of computing human motion predictions that account for such factors. We formulate the task as an MDP planning problem with stochastic policies and propose a weighted random walk algorithm in which each agent is locally influenced by social forces from other nearby agents. The novelty of this paper is that we incorporate social grouping information into the prediction process reflecting the soft formation constraints that groups typically impose to their members’ motion. We show that our method makes more accurate predictions than three state-of-the-art methods in terms of probabilistic and geometrical performance metrics.

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    Human Motion Prediction Under Social Grouping Constraints
  • 322.
    Saarinen, Jari
    et al.
    Department of Automation and Systems Technology, Aalto University, Alto, Finland.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Independent Markov Chain Occupancy Grid Maps for Representation of Dynamic Environments2012In: 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, New York, USA: IEEE, 2012, p. 3489-3495Conference paper (Refereed)
    Abstract [en]

    In this paper we propose a new grid based approach to model a dynamic environment. Each grid cell is assumed to be an independent Markov chain (iMac) with two states. The state transition parameters are learned online and modeled as two Poisson processes. As a result, our representation not only encodes the expected occupancy of the cell, but also models the expected dynamics within the cell. The paper also presents a strategy based on recency weighting to learn the model parameters from observations that is able to deal with non-stationary cell dynamics. Moreover, an interpretation of the model parameters with discussion about the convergence rates of the cells is presented. The proposed model is experimentally validated using offline data recorded with a Laser Guided Vehicle (LGV) system running in production use.

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    Independent Markov Chain Occupancy Grid Maps for Representation of Dynamic Environments
  • 323.
    Sadikov, Aleksander
    et al.
    Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
    Groznik, Vida
    Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
    Možina, Martin
    Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
    Žabkar, Jure
    Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
    Nyholm, Dag
    Department of Neuroscience, Neurology, Uppsala University, Uppsala, Sweden.
    Memedi, Mevludin
    Örebro University, Örebro University School of Business. Computer Engineering, Dalarna University, Borlänge, Sweden.
    Georgiev, Dejan
    Department of Neurology, Ljubljana University Medical Centre, Ljubljana, Slovenia.
    Feasibility of spirography features for objective assessment of motor function in Parkinson's disease2017In: Artificial Intelligence in Medicine, ISSN 0933-3657, E-ISSN 1873-2860, Vol. 81, p. 54-62Article in journal (Refereed)
    Abstract [en]

    Objective: Parkinson's disease (PD) is currently incurable, however proper treatment can ease the symptoms and significantly improve the quality of life of patients. Since PD is a chronic disease, its efficient monitoring and management is very important. The objective of this paper was to investigate the feasibility of using the features and methodology of a spirography application, originally designed to detect early Parkinson's disease (PD) motoric symptoms, for automatically assessing motor symptoms of advanced PD patients experiencing motor fluctuations. More specifically, the aim was to objectively assess motor symptoms related to bradykinesias (slowness of movements occurring as a result of under-medication) and dyskinesias (involuntary movements occurring as a result of over-medication).

    Materials and methods: This work combined spirography data and clinical assessments from a longitudinal clinical study in Sweden with the features and pre-processing methodology of a Slovenian spirography application. The study involved 65 advanced PD patients and over 30,000 spiral-drawing measurements over the course of three years. Machine learning methods were used to learn to predict the “cause” (bradykinesia or dyskinesia) of upper limb motor dysfunctions as assessed by a clinician who observed animated spirals in a web interface. The classification model was also tested for comprehensibility. For this purpose a visualisation technique was used to present visual clues to clinicians as to which parts of the spiral drawing (or its animation) are important for the given classification.

    Results: Using the machine learning methods with feature descriptions and pre-processing from the Slovenian application resulted in 86% classification accuracy and over 0.90 AUC. The clinicians also rated the computer's visual explanations of its classifications as at least meaningful if not necessarily helpful in over 90% of the cases.

    Conclusions: The relatively high classication accuracy and AUC demonstrates the usefulness of this approach for objective monitoring of PD patients. The positive evaluation of computer's explanations suggests the potential use of this methodology in a decision support setting.

  • 324.
    Salamati, Mahnaz
    et al.
    Örebro University, Department of Technology.
    Stranneby, Dag
    Örebro University, Department of Technology.
    Electromagnetic signatures as a tool for connectionless test2003In: IEEE Design & Test of Computers, ISSN 0740-7475, Vol. 20, no 2, p. 26-30Article in journal (Refereed)
    Abstract [en]

    When we test boards, we usually think in terms of traditional electrical test (in-circuit, flying probe) and nonelectrical test (optical, x-ray). This Orebro University article develops an alternative, connectionless technique based on scanning the electromagnetic field generated by active on-board devices. Could this make it into industry as an additional diagnostic tool?

  • 325.
    Salamati, Mahnaz
    et al.
    Örebro University, Department of Technology.
    Stranneby, Dag
    Örebro University, Department of Technology.
    Electromagnetic signatures as a tool for Connectionless Test (CT)2002Conference paper (Other academic)
    Abstract [en]

    Today’s electronic products and subassemblies are highly integrated, miniaturized devices having complex functionality. Final test and troubleshooting using conventional test points, probes and bed-of-nails techniques are becoming harder, and are in many cases not even possible. Further, due to increasing production volumes, the time needed for testing is a critical factor. An alternative way to test a device is to employ Connectionless Test (CT). The idea is to measure the electromagnetic (EM) field surrounding the DeviceUnder Test (DUT) during different modes of operation.Using the CAD data for the DUT, an Electromagnetic signature can be created from the measured EM data.The obtained signature is matched to earlier signatures stored in an adaptive database that is being updated continuously. The database not only contains signatures from “known good” devices, but also signatures obtained from some typical failure types. In this way, the DUT can be classified as working properly, suffering from a previously known type of failure or having a “new”, hitherto unknown malfunction. Since the electromagnetic signature also contains spatial information, it is an interesting tool in thetroubleshooting process. Besides the type of failure, an estimate of the location of the problem may be extracted from the signature. Initial practical tests have shown that the CT method outlined above works for both “analog” as well as “digital” electronic products having medium complexity.

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    fulltext
  • 326.
    Salvado, João
    et al.
    Örebro University, School of Science and Technology.
    Krug, Robert
    Robotics, Perception and Learning Lab, KTH Royal Institute of Technology, Stockholm, Sweden.
    Mansouri, Masoumeh
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Motion Planning and Goal Assignment for Robot Fleets Using Trajectory Optimization2018In: 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 7940-7946Conference paper (Refereed)
    Abstract [en]

    This paper is concerned with automating fleets of autonomous robots. This involves solving a multitude of problems, including goal assignment, motion planning, and coordination, while maximizing some performance criterion. While methods for solving these sub-problems have been studied, they address only a facet of the overall problem, and make strong assumptions on the use-case, on the environment, or on the robots in the fleet. In this paper, we formulate the overall fleet management problem in terms of Optimal Control. We describe a scheme for solving this problem in the particular case of fleets of non-holonomic robots navigating in an environment with obstacles. The method is based on a two-phase approach, whereby the first phase solves for fleet-wide boolean decision variables via Mixed Integer Quadratic Programming, and the second phase solves for real-valued variables to obtain an optimized set of trajectories for the fleet. Examples showcasing the features of the method are illustrated, and the method is validated experimentally.

  • 327.
    Samadi, Mahnaz
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Connectionless Testing2005Conference paper (Other academic)
  • 328.
    Samadi, Mahnaz
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Electromagnetic signatures for Test and Troubleshooting2003Conference paper (Other academic)
  • 329.
    Sathyakeerthy, Subhash
    et al.
    Örebro University, School of Science and Technology.
    Di Rocco, Maurizio
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Scaling up ubiquitous robotic systems from home to town (and beyond)2013In: UbiComp '13 Adjunct Proceedings of the 2013 ACM conference on Pervasive and ubiquitous computing adjunct publication, Association for Computing Machinery (ACM), 2013, p. 107-110Conference paper (Refereed)
  • 330.
    Scandurra, Isabella
    et al.
    Department of information technology, Uppsala university, Uppsala, Sweden.
    Hägglund, Maria
    Persson, Anne
    Skövde University, Skövde, Sweden.
    Åhlfeldt, Rose-Mharie
    Informatics, Skövde University, Skövde, Sweden.
    Disturbing or Facilitating? On the Usability of Swedish eHealth Systems 20132014In: E-Health – For Continuity of Care: Proceedings of MIE2014 / [ed] Christian Lovis, Brigitte Séroussi, Arie Hasman; Louise Pape-Haugaard; Osman Saka; Stig Kjær Andersen, Amsterdam: IOS Press, 2014, Vol. 205, p. 221-225Conference paper (Refereed)
    Abstract [en]

    As many evaluations show, healthcare organizations do not accomplish the intended effects of their eHealth systems due to inadequate usability. On behalf of the Swedish Ministry of Health and Social Affairs, the usability of current eHealth systems in Swedish healthcare have been analysed from the perspective of healthcare and social service professionals. The objective of the study was to report on current problems, potential solutions as well as to relate these to research in relevant areas. Using a participatory approach, seven workshops were held where researchers within health informatics collaborated with staff from different care providers, representatives of the national associations of health and social care professionals and the national eHealth system vendor organization. This paper presents a foundation for further development of eHealth systems, condensed into 10 issues that the Swedish health and social care professionals find imperative to improve. The study emphasizes that the development of eHealth systems is always a matter of organizational and process development and must be integrated into the care practice improvement process. Further, based on the findings, some identified challenges are discussed.

  • 331.
    Schaffernicht, Erik
    et al.
    Örebro University, School of Science and Technology.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Mobile robots for learning spatio-temporal interpolation models in sensor networks - The Echo State map approach: The Echo State map approach2017In: 2017 IEEE International Conference on Robotics and Automation (ICRA), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 2659-2665Conference paper (Refereed)
    Abstract [en]

    Sensor networks have limited capabilities to model complex phenomena occuring between sensing nodes. Mobile robots can be used to close this gap and learn local interpolation models. In this paper, we utilize Echo State Networks in order to learn the calibration and interpolation model between sensor nodes using measurements collected by a mobile robot. The use of Echo State Networks allows to deal with temporal dependencies implicitly, while the spatial mapping with a Gaussian Process estimator exploits the fact that Echo State Networks learn linear combinations of complex temporal dynamics. The resulting Echo State Map elegantly combines spatial and temporal cues into a single representation. We showcase the method in the exposure modeling task of building dust distribution maps for foundries, a challenge which is of great interest to occupational health researchers. Results from simulated data and real world experiments highlight the potential of Echo State Maps. While we focus on particulate matter measurements, the method can be applied for any other environmental variables like temperature or gas concentration.

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    Schaffernicht-ICRA2017-EchoStateMaps.pdf
  • 332.
    Schaffernicht, Erik
    et al.
    Örebro University, School of Science and Technology.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Bayesian Spatial Event Distribution Grid Maps for Modeling the Spatial Distribution of Gas Detection Events2014In: Sensor Letters, ISSN 1546-198X, E-ISSN 1546-1971, Vol. 12, no 6-7, p. 1142-1146Article in journal (Refereed)
    Abstract [en]

    In this paper we introduce a novel gas distribution mapping algorithm, Bayesian Spatial Event Distribution (BASED), that, instead of modeling the spatial distribution of a quasi-continuous gas concentration, models the spatial distribution of gas events, for example detection and non-detection of a target gas. The proposed algorithm is based on the Bayesian Inference framework and models the likelihood of events at a certain location with a Bernoulli distribution. In order to avoid overfitting, a Bayesian approach is used with a beta distribution prior for the parameter μ that governs the Bernoulli distribution. In this way, the posterior distribution maintains the same form of the prior, i.e., will be a beta distribution as well, enabling a simple approach for sequential learning. To learn a map composed of beta distributions, we discretize the inspection area into a grid and extrapolate from local measurements using Gaussian kernels. We demonstrate the proposed algorithm for MOX sensors and a photo ionization detector mounted on a mobile robot and show how qualitatively similar maps are obtained from very different gas sensors.

  • 333.
    Schindler, Maike
    et al.
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Chadalavada, Ravi
    Örebro University, School of Science and Technology.
    Ögren, Magnus
    Örebro University, School of Science and Technology.
    Creativity in the eye of the student: Refining investigations of mathematical creativity using eye-tracking goggles2016In: Proceedings of the 40th Conference of the International Group for the Psychology of Mathematics Education (PME) / [ed] C. Csíkos, A. Rausch, & J. Szitányi, 2016Conference paper (Refereed)
    Abstract [en]

    Mathematical creativity is increasingly important for improved innovation and problem-solving. In this paper, we address the question of how to best investigate mathematical creativity and critically discuss dichotomous creativity scoring schemes. In order to gain deeper insights into creative problem-solving processes, we suggest the use of mobile, unobtrusive eye-trackers for evaluating students’ creativity in the context of Multiple Solution Tasks (MSTs). We present first results with inexpensive eye-tracking goggles that reveal the added value of evaluating students’ eye movements when investigating mathematical creativity—compared to an analysis of written/drawn solutions as well as compared to an analysis of simple videos.

  • 334.
    Schindler, Maike
    et al.
    Örebro University, School of Science and Technology. University of Cologne, Cologne, Germany.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Differences in Quantity Recognition Between Students with and without Mathematical Difficulties Analyzed Through Eye: Analysis Through Eye-Tracking and AI2019In: Proceedings of the 43rd Conference of the International Group for the Psychology of Mathematics Education / [ed] M. Graven, H. Venkat, A. Essien & P. Vale, PME , 2019, Vol. 3, p. 281-288Conference paper (Refereed)
    Abstract [en]

    Difficulties in mathematics learning are an important topic in practice and research. In particular, researchers and practitioners need to identify students’ needs for support to teach and help them adequately. However, empirical research about group differences of students with and without mathematical difficulties (MD) is still scarce. Previous research suggests that students with MD may differ in their quantity recognition strategies in structured whole number representations from students without MD. This study uses eye-tracking (ET), combined with Artificial Intelligence (AI), in particular pattern recognition methods, to analyze group differences in gaze patterns in quantity recognition of N=164 fifth grade students.

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    Differences in Quantity Recognition Between Students with and without Mathematical Difficulties Analyzed Through Eye
  • 335.
    Shiraz, A.
    et al.
    Department of Electronic and Electrical Engineering, University College London, London, United Kingdom.
    Khodadad, Davood
    Örebro University, School of Science and Technology.
    Nordebo, S.
    Department of Physics and Electrical Engineering, Linnaeus University, Växjö, Sweden.
    Yerworth, R.
    Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom.
    Frerichs, I.
    Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Kiel, Germany.
    van Kaam, A.
    Department of Neonatology, Emma Children’s Hospital, Academic Medical Center, Amsterdam, The Netherlands; Department of Neonatology, VU Medical Center, Amsterdam, The Netherlands.
    Kallio, M.
    PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, Oulu, Finland; Department of Children and Adolescents, Oulu University Hospital, Finland.
    Papadouri, T.
    Bayford, R.
    Department of Electronic and Electrical Engineering, University College London, London, United Kingdom.
    Demosthenous, A.
    Department of Electronic and Electrical Engineering, University College London, London, United Kingdom.
    Compressive sensing in electrical impedance tomography for breathing monitoring2019In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 40, no 3, article id 034010Article in journal (Refereed)
    Abstract [en]

    Objective: Electrical impedance tomography (EIT) is a functional imaging technique in which cross-sectional images of structures are reconstructed based on boundary trans-impedance measurements. Continuous functional thorax monitoring using EIT has been extensively researched. Increasing the number of electrodes, number of planes and frame rate may improve clinical decision making. Thus, a limiting factor in high temporal resolution, 3D and fast EIT is the handling of the volume of raw impedance data produced for transmission and its subsequent storage. Owing to the periodicity (i.e. sparsity in frequency domain) of breathing and other physiological variations that may be reflected in EIT boundary measurements, data dimensionality may be reduced efficiently at the time of sampling using compressed sensing techniques. This way, a fewer number of samples may be taken.

    Approach: Measurements using a 32-electrode, 48-frames-per-second EIT system from 30 neonates were post-processed to simulate random demodulation acquisition method on 2000 frames (each consisting of 544 measurements) for compression ratios (CRs) ranging from 2 to 100. Sparse reconstruction was performed by solving the basis pursuit problem using SPGL1 package. The global impedance data (i.e. sum of all 544 measurements in each frame) was used in the subsequent studies. The signal to noise ratio (SNR) for the entire frequency band (0 Hz–24 Hz) and three local frequency bands were analysed. A breath detection algorithm was applied to traces and the subsequent error-rates were calculated while considering the outcome of the algorithm applied to a down-sampled and linearly interpolated version of the traces as the baseline.

    Main results: SNR degradation was generally proportional with CR. The mean degradation for 0 Hz–8 Hz (of interest for the target physiological variations) was below ~15 dB for all CRs. The error-rates in the outcome of the breath detection algorithm in the case of decompressed traces were lower than those associated with the corresponding down-sampled traces for CR  ⩾  25, corresponding to sub-Nyquist rate for breathing frequency. For instance, the mean error-rate associated with CR  =  50 was ~60% lower than that of the corresponding down-sampled traces.

    Significance: To the best of our knowledge, no other study has evaluated the applicability of compressive sensing techniques on raw boundary impedance data in EIT. While further research should be directed at optimising the acquisition and decompression techniques for this application, this contribution serves as the baseline for future efforts.

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    Compressive sensing in electrical impedance tomography for breathing monitoring
  • 336.
    Siddiqui, J. Rafid
    et al.
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Khatibi, Siamak
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Bio-inspired Metaheuristic based Visual Tracking and Ego-motion Estimation2014In: Proceedings of the 3rd International Conference on Pattern Recognition Applications and Methods / [ed] Maria De Marsico, Antoine Tabbone and Ana Fred, SciTePress , 2014, p. 569-579Conference paper (Refereed)
    Abstract [en]

    The problem of robust extraction of ego-motion from a sequence of images for an eye-in-hand camera configuration is addressed. A novel approach toward solving planar template based tracking is proposed which performs a non-linear image alignment and a planar similarity optimization to recover camera transformations from planar regions of a scene. The planar region tracking problem as a motion optimization problem is solved by maximizing the similarity among the planar regions of a scene. The optimization process employs an evolutionary metaheuristic approach in order to address the problem within a large non-linear search space. The proposed method is validated on image sequences with real as well as synthetic image datasets and found to be successful in recovering the ego-motion. A comparative analysis of the proposed method with various other state-of-art methods reveals that the algorithm succeeds in tracking the planar regions robustly and is comparable to the state-of-the art methods. Such an application of evolutionary metaheuristic in solving complex visual navigation problems can provide different perspective and could help in improving already available methods.

  • 337.
    Siddiqui, J. Rafid
    et al.
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden .
    Khatibi, Siamak
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden .
    Robust Place Recognition with an Application to Semantic Topological Mapping2013In: Sixth International Conference on Machine Vision (ICMV 2013) / [ed] Branislav Vuksanovic; Jianhong Zhou; Antanas Verikas, SPIE - International Society for Optical Engineering, 2013Conference paper (Refereed)
    Abstract [en]

    The problem of robust and invariant representation of places is being addressed. A place recognition technique is proposed followed by an application to a semantic topological mapping. The proposed technique is evaluated on a robot localization database which consists of a large set of images taken under various weather conditions. The results show that the proposed method can robustly recognize the places and is invariant to geometric transformations, brightness changes and noise. The comparative analysis with the state-of-the-art semantic place description methods show that the method outperforms the competing methods and exhibits better average recognition rates.

  • 338.
    Siddiqui, J. Rafid
    et al.
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Khatibi, Siamak
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Robust visual odometry estimation of road vehicle from dominant surfaces for large-scale mapping2015In: IET Intelligent Transport Systems, ISSN 1751-956X, E-ISSN 1751-9578, Vol. 9, no 3, p. 314-322Article in journal (Refereed)
    Abstract [en]

    Every urban environment contains a rich set of dominant surfaces which can provide a solid foundation for visual odometry estimation. In this work visual odometry is robustly estimated by computing the motion of camera mounted on a vehicle. The proposed method first identifies a planar region and dynamically estimates the plane parameters. The candidate region and estimated plane parameters are then tracked in the subsequent images and an incremental update of the visual odometry is obtained. The proposed method is evaluated on a navigation dataset of stereo images taken by a car mounted camera that is driven in a large urban environment. The consistency and resilience of the method has also been evaluated on an indoor robot dataset. The results suggest that the proposed visual odometry estimation can robustly recover the motion by tracking a dominant planar surface in the Manhattan environment. In addition to motion estimation solution a set of strategies are discussed for mitigating the problematic factors arising from the unpredictable nature of the environment. The analyses of the results as well as dynamic environmental strategies indicate a strong potential of the method for being part of an autonomous or semi-autonomous system.

  • 339.
    Siddiqui, J. Rafid
    et al.
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Khatibi, Siamak
    Department of Computing, Blekinge Institute of Technology, Karlskrona, Sweden.
    Semantic Urban Maps2014In: 22nd International Conference on Pattern Recognition: Proceedings, IEEE conference proceedings, 2014, p. 4050-4055Conference paper (Refereed)
    Abstract [en]

    A novel region based 3D semantic mapping method is proposed for urban scenes. The proposed Semantic Urban Maps (SUM) method labels the regions of segmented images into a set of geometric and semantic classes simultaneously by employing a Markov Random Field based classification framework. The pixels in the labeled images are back-projected into a set of 3D point-clouds using stereo disparity. The point-clouds are registered together by incorporating the motion estimation and a coherent semantic map representation is obtained. SUM is evaluated on five urban benchmark sequences and is demonstrated to be successful in retrieving both geometric as well as semantic labels. The comparison with relevant state-of-art method reveals that SUM is competitive and performs better than the competing method in average pixel-wise accuracy.

  • 340.
    Silva-Lopez, Lia Susana del Carmen
    et al.
    Örebro University, School of Science and Technology.
    Ullberg, Jonas
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    On combining a context recognition system and a configuration planner for personalised ambient assisted living2013In: Communications in Computer and Information Science / [ed] Juan Carlos Augusto, Reiner Wichert, Rem Collier, David Keyson, Ali Salah, and Ah-Hwee Tan, Örebro: Örebro universitet , 2013Conference paper (Refereed)
    Download full text (pdf)
    AmI2013-lcsz-jug-lkn
  • 341.
    Sjödahl, Mikael
    et al.
    Luleå University of Technology, Lkuleå, Sweden.
    Hallstig, Emil
    Optronic, Sekellefteå, Sweden.
    Khodadad, Davood
    Luleå University of Technology, Lkuleå, Sweden.
    Multi-spectral speckles: theory and applications2012In: Speckle 2012: V International Conference on Speckle Metrology / [ed] Ángel Fernandez Doval & Cristina Trillo, SPIE - International Society for Optical Engineering, 2012, Vol. 8413, article id 841306Conference paper (Refereed)
    Abstract [en]

    The objective of this paper is to discuss the properties and a few applications of multi-spectral speckles. The paper starts with a theoretical section where the correlation properties of multi-spectral speckles are detailed for the case of reflective imaging geometry. Both a free-space geometry and an imaging geometry are detailed. As an application example effects and possibilities provided by the theory in a measurement of surface shape of a generally shaped object from a dual-wavelength holographic recording are detailed. It is showed that the same phase profile is obtained from integration of speckle movements and phase unwrapping and they are therefore exchangeable quantities.

  • 342.
    Sjöholm, Olof
    Örebro University, School of Science and Technology.
    ANALYS OCH KONSTRUKTION AV SWITCHADE NÄTAGGREGAT2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    same time more functions need to get built in. Because of this is a big component like a torodial transformer is no longer desirable. But is it possible to change the design of a linear power supply to a switch mode power supply without any problems?

    This paper presents the basic theories of how switch mode power supplies work, together with a description of how an electronic prototype is developed. An introduction on how electromagnetic interference measurements are done will also be presented. We are going to see that a working prototype can be developed. But the target efficiency is not reached, there is need for improvement. But remember, a prototype is the first step to a finished product.

    Download full text (pdf)
    fulltext
  • 343.
    Skoglund, Alexander
    et al.
    Örebro University, Department of Technology.
    Iliev, Boyko
    Örebro University, Department of Technology.
    Programming by demonstration of robots using task primitives2007In: Servo magazine, Vol. 5, no 12, p. 46-50Article in journal (Other (popular science, discussion, etc.))
  • 344.
    Skoglund, Alexander
    et al.
    AASS Learning Systems Lab, Örebro Universitet, Örebro, Sweden.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Palm, Rainer
    AASS Learning Systems Lab, Örebro Universitet, Örebro, Sweden.
    Programming-by-demonstration of reaching motions: a next-state-planner approach2010In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 58, no 5, p. 607-621Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel approach to skill acquisition from human demonstration. A robot manipulator with a morphology which is very different from the human arm simply cannot copy a human motion, but has to execute its own version of the skill. When a skill once has been acquired the robot must also be able to generalize to other similar skills, without a new learning process. By using a motion planner that operates in an object-related world frame called hand-state, we show that this representation simplifies skill reconstruction and preserves the essential parts of the skill. (C) 2010 Elsevier B.V. All rights reserved.

  • 345. Skoglund, Alexander
    et al.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Palm, Rainer
    Programming-by-demonstration of robot motions2010In: Robot intelligence: an advanced knowledge processing approach / [ed] Honghai Liu, Dongbing Gu, Robert J. Howlett, Yonghuai Liu, New York: Springer , 2010, p. 1-24Chapter in book (Other academic)
  • 346.
    Soron, Mikael
    Örebro University, Department of Technology.
    Robot system for flexible 3D friction stir welding2007Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Applying Friction Stir Welding (FSW) on complex joint geometries requires not only a machine with 3-dimesional work space capacity, but also a sound definition of the part geometry as well as knowledge about the process. Having a joining process, such as FSW, with great characteristics from both seam quality and environmental perspective, but yet only a minor presence in the manufacturing industry may be related to flexibility and cost issues. The machines that are present in production today are mainly devoted towards one single task, with small if any possibility to apply changes. The use of FSW has therefore mainly been introduced in areas where there are extreme demands on the seam quality, or in large scale production. In order to truly challenge the existing solutions using fusion welding techniques, we propose a solution consisting of an industrial robot, which may solve the machine issues to a great extent as well as the flexibility issues by the implementation of planning and control algorithms.

    In this thesis we aim to develop a general methodology towards 3-dimensional FSW on complex objects. This include a robot prototype based on a standard industrial design, modified to carry out the process to a satisfactory extend. The prototype implementation includes software to control the motion of the welding tool, explicitly in the axial direction by the use of force feedback control and implicitly in the plane perpendicular to the axial direction to avoid path deviations. Other tools proposed in this thesis include planning software to create complex paths, both online and off-line, to consider not only the aspects regarding the robot's motion, but also including restraints due to the FSW process.

    The evaluation of the proposed system is conducted with an objective to define weldability, in term of alloys, thicknesses and speed, to verify the path planning algorithms for an online as well as an off-line scenario, and to verify the control algorithms response to path deviation due to manipulator compliance, and merge the results from those studies into a discussion on usability of the proposed system and application areas and operations suitable.

  • 347.
    Stoyanov, Todor
    et al.
    Örebro University, School of Science and Technology.
    Louloudi, Athanasia
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Comparative evaluation of range sensor accuracy in indoor environments2011In: Proceedings of the 5th European Conference on Mobile Robots, ECMR 2011 / [ed] Achim J. Lilienthal, Tom Duckett, 2011, p. 19-24Conference paper (Refereed)
    Abstract [en]

    3D range sensing is one of the important topics in robotics, as it is often a component in vital autonomous subsystems like collision avoidance, mapping and semantic perception. The development of affordable, high frame rate and precise 3D range sensors is thus of considerable interest. Recent advances in sensing technology have produced several novel sensors that attempt to meet these requirements. This work is concerned with the development of a holistic method for accuracy evaluation of the measurements produced by such devices. A method for comparison of range sensor output to a set of reference distance measurements is proposed. The approach is then used to compare the behavior of three integrated range sensing devices, to that of a standard actuated laser range sensor. Test cases in an uncontrolled indoor environment are performed in order to evaluate the sensors’ performance in a challenging, realistic application scenario.

    Download full text (pdf)
    Stoyanov_etal_2011-ECMR-3D_Range_Sensors_Accuracy_Evaluation.pdf
  • 348.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    A Primer on PIM2014In: Electronic environment, no 4, p. 10-12Article in journal (Other academic)
    Abstract [en]

    PIM is an acronym for Passive InterModulation, an interference problem in wireless systems. The problem is not new, but has been known since long time back by designers of, for instance cell phone systems, space probes, connectors, coaxial cables, antennas and filters. The problem most frequently occurs, when dealing with high RF-currents in confined spaces. In this text, the basic theories behind PIM will be briefly discussed.

    Download full text (pdf)
    fulltext
  • 349.
    Stranneby, Dag
    KTH Royal Institute of Technology, Stockholm, Sweden.
    An adaptive frequency hopping (AFH) system for digital shortwave communication1993In: Milinf - seminar proceedings, Enköping, 8-10 juni, 1993 / [ed] Bengtsson,Christopher, 1993Conference paper (Other academic)
  • 350.
    Stranneby, Dag
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Assigning power and frequency to links in HF radio networks using a Neural Network approach1995In: HF 95 Conference Proceedings: 15-17 August 1995, Fårö / [ed] Carlsson, Olov, Växjö, 1995Conference paper (Other academic)
    Abstract [en]

    A method af assigning transmitting power and frequency to narrow band links exposed to nonselective fading and self induced interference in an HF radio data network is suggested. The method uses vector optimization by means of a feedforward neural network.The network performance measure used is a weighted sum of mutual information for all links in the network. The suggested assignment method can be used for power and frequency planning using simulated fading and interference data. It can also be used with actual measured link data in an adaptive on-line system. The method is capable of handling links utilizing frequency diversity and can also take LPD/LPI aspects into account. Simulation results indicate that the degree of correlation in space and frequency between different links palys ab important role in the assignment process.

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