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  • 1.
    Abbasi, Mazhar Ali
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, Mushtaque
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khan, Yaqoob
    Quaid-e-Azam University Campus, Islamabad, Pakistan.
    Khan, Azam
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures2012In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, no 11, p. 15424-15437Article in journal (Refereed)
    Abstract [en]

    In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

  • 2.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Snäll, Jonatan
    KTH, School of Technology and Health (STH).
    Aslamy, Benjamin
    KTH, School of Technology and Health (STH).
    Abtahi, Shirin
    KTH, School of Technology and Health (STH).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Boras, Sweden.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institute, Sweden.
    Biosignal PI, an Affordable Open-Source ECG and Respiration Measurement System2014In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 1, p. 93-109Article in journal (Refereed)
    Abstract [en]

    Bioimedical pilot projects e.g., telemedicine, homecare, animal and human trials usually involve several physiological measurements. Technical development of these projects is time consuming and in particular costly. A versatile but affordable biosignal measurement platform can help to reduce time and risk while keeping the focus on the important goal and making an efficient use of resources. In this work, an affordable and open source platform for development of physiological signals is proposed. As a first step an 8–12 leads electrocardiogram (ECG) and respiration monitoring system is developed. Chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 for patient safety. The result shows the potential of this platform as a base for prototyping compact, affordable, and medically safe measurement systems. Further work involves both hardware and software development to develop modules. These modules may require development of front-ends for other biosignals or just collect data wirelessly from different devices e.g., blood pressure, weight, bioimpedance spectrum, blood glucose, e.g., through Bluetooth. All design and development documents, files and source codes will be available for non-commercial use through project website, BiosignalPI.org.

  • 3. Abtahi, Farhad
    et al.
    Snäll, Jonathan
    Aslamy, Benjamin
    Abtahi, Shirin
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Biosignal PI, an Affordable Open-Source ECG and Respiration Measurement System2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 1, p. 93-109Article in journal (Refereed)
    Abstract [en]

    Bioimedical pilot projects e.g., telemedicine, homecare, animal and human trials usually involve several physiological measurements. Technical development of these projects is time consuming and in particular costly. A versatile but affordable biosignal measurement platform can help to reduce time and risk while keeping the focus on the important goal and making an efficient use of resources. In this work, an affordable and open source platform for development of physiological signals is proposed. As a first step an 8–12 leads electrocardiogram (ECG) and respiration monitoring system is developed. Chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 for patient safety. The result shows the potential of this platform as a base for prototyping compact, affordable, and medically safe measurement systems. Further work involves both hardware and software development to develop modules. These modules may require development of front-ends for other biosignals or just collect data wirelessly from different devices e.g., blood pressure, weight, bioimpedance spectrum, blood glucose, e.g., through Bluetooth. All design and development documents, files and source codes will be available for non-commercial use through project website, BiosignalPI.org.

  • 4.
    Aghaeinezhadfirouzja, S.
    et al.
    Department of Electronics Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Liu, H.
    Department of Electronics Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Balador, Ali
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. RISE SICS Västerås, Sweden.
    Practical 3-D beam pattern based channel modeling for multi-polarized massive MIMO systems2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id 1186Article in journal (Refereed)
    Abstract [en]

    In this paper, a practical non-stationary three-dimensional (3-D) channel models for massive multiple-input multiple-output (MIMO) systems, considering beam patterns for different antenna elements, is proposed. The beam patterns using dipole antenna elements with different phase excitation toward the different direction of travels (DoTs) contributes various correlation weights for rays related towards/from the cluster, thus providing different elevation angle of arrivals (EAoAs) and elevation angle of departures (EAoDs) for each antenna element. These include the movements of the user that makes our channel to be a non-stationary model of clusters at the receiver (RX) on both the time and array axes. In addition, their impacts on 3-D massive MIMO channels are investigated via statistical properties including received spatial correlation. Additionally, the impact of elevation/azimuth angles of arrival on received spatial correlation is discussed. Furthermore, experimental validation of the proposed 3-D channel models on azimuth and elevation angles of the polarized antenna are specifically evaluated and compared through simulations. The proposed 3-D generic models are verified using relevant measurement data.

  • 5.
    Aghaeinezhadfirouzja, Saeid
    et al.
    Shanghai Jiao Tong University, China.
    Liu, Hui
    Shanghai Jiao Tong University, China.
    Balador, Ali
    RISE - Research Institutes of Sweden, ICT, SICS. Mälardalen University, Sweden.
    Practical 3-D beam pattern based channel modeling for multi-polarized massive MIMO systems2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id 1186Article in journal (Refereed)
    Abstract [en]

    In this paper, a practical non-stationary three-dimensional (3-D) channel models for massive multiple-input multiple-output (MIMO) systems, considering beam patterns for different antenna elements, is proposed. The beam patterns using dipole antenna elements with different phase excitation toward the different direction of travels (DoTs) contributes various correlation weights for rays related towards/from the cluster, thus providing different elevation angle of arrivals (EAoAs) and elevation angle of departures (EAoDs) for each antenna element. These include the movements of the user that makes our channel to be a non-stationary model of clusters at the receiver (RX) on both the time and array axes. In addition, their impacts on 3-D massive MIMO channels are investigated via statistical properties including received spatial correlation. Additionally, the impact of elevation/azimuth angles of arrival on received spatial correlation is discussed. Furthermore, experimental validation of the proposed 3-D channel models on azimuth and elevation angles of the polarized antenna are specifically evaluated and compared through simulations. The proposed 3-D generic models are verified using relevant measurement data.

  • 6.
    Aghanavesi, Somayeh
    et al.
    Dalarna Univ, Falun, Sweden.
    Memedi, Mevludin
    Örebro Univ, Örebro, Sweden.
    Dougherty, Mark
    Dalarna Univ, Falun, Sweden.
    Nyholm, Dag
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Westin, Jerker
    Dalarna Univ, Falun, Sweden.
    Verification of a Method for Measuring Parkinson's Disease Related Temporal Irregularity in Spiral Drawings2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 10, article id 2431Article in journal (Refereed)
    Abstract [en]

    -value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

  • 7.
    Aghanavesi, Somayeh
    et al.
    School of Technology and Business Studies, Computer Engineering, Dalarna University, Falun, Sweden.
    Memedi, Mevludin
    Örebro University, Örebro University School of Business.
    Dougherty, Mark
    School of Technology and Business Studies, Computer Engineering, Dalarna University, Falun, Sweden.
    Nyholm, Dag
    Department of Neuroscience, Neurology, Uppsala University, Uppsala, Sweden.
    Westin, Jerker
    School of Technology and Business Studies, Computer Engineering, Dalarna University, Falun, Sweden.
    Verification of a Method for Measuring Parkinson’s Disease Related Temporal Irregularity in Spiral Drawings2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 10, article id 2341Article in journal (Refereed)
    Abstract [en]

    Parkinson’s disease (PD) is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS) for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS) and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication) to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

  • 8.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nyholm, Dag
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Verification of a method for measuring Parkinson’s disease related temporal irregularity in spiral drawings2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 10, article id 2341Article in journal (Refereed)
    Abstract [en]

    Parkinson's disease (PD) is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS) for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS) and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication) to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

  • 9.
    Akbar, Mariam
    et al.
    COMSATS Institute of Information Technology, Islamabad.
    Javaid, Nadeem
    COMSATS Institute of Information Technology, Islamabad.
    Kahn, Ayesha Hussain
    COMSATS Institute of Information Technology, Islamabad.
    Imran, Muhammad Al
    College of Computer and Information Sciences, Almuzahmiyah, King Saud University.
    Shoaib, Muhammad
    College of Computer and Information Sciences, Almuzahmiyah, King Saud University.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Efficient Data Gathering in 3D Linear Underwater Wireless Sensor Networks Using Sink Mobility2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 3, article id 404Article in journal (Refereed)
    Abstract [en]

    Due to the unpleasant and unpredictable underwater environment, designing an energy-efficient routing protocol for underwater wireless sensor networks (UWSNs) demands more accuracy and extra computations. In the proposed scheme, we introduce a mobile sink (MS), i.e., an autonomous underwater vehicle (AUV), and also courier nodes (CNs), to minimize the energy consumption of nodes. MS and CNs stop at specific stops for data gathering; later on, CNs forward the received data to the MS for further transmission. By the mobility of CNs and MS, the overall energy consumption of nodes is minimized. We perform simulations to investigate the performance of the proposed scheme and compare it to preexisting techniques. Simulation results are compared in terms of network lifetime, throughput, path loss, transmission loss and packet drop ratio. The results show that the proposed technique performs better in terms of network lifetime, throughput, path loss and scalability

  • 10.
    Alhashimi, Anas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Varagnolo, Damiano
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Joint Temperature-Lasing Mode Compensation for Time-of-Flight LiDAR Sensors2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 12, p. 31205-31223Article in journal (Refereed)
    Abstract [en]

    We propose an expectation maximization (EM) strategy for improving the precision of time of flight (ToF) light detection and ranging (LiDAR) scanners. The novel algorithm statistically accounts not only for the bias induced by temperature changes in the laser diode, but also for the multi-modality of the measurement noises that is induced by mode-hopping effects. Instrumental to the proposed EM algorithm, we also describe a general thermal dynamics model that can be learned either from just input-output data or from a combination of simple temperature experiments and information from the laser’s datasheet. We test the strategy on a SICK LMS 200 device and improve its average absolute error by a factor of three.

  • 11.
    Al-Hilli, Safa
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    The pH Response and Sensing Mechanism of n-Type ZnO/Electrolyte Interfaces2009In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 9, no 9, p. 7445-7480Article in journal (Refereed)
    Abstract [en]

    Ever since the discovery of the pH-sensing properties of ZnO crystals, researchers have been exploring their potential in electrochemical applications. The recent expansion and availability of chemical modification methods has made it possible to generate a new class of electrochemically active ZnO nanorods. This reduction in size of ZnO (to a nanocrystalline form) using new growth techniques is essentially an example of the nanotechnology fabrication principle. The availability of these ZnO nanorods opens up an entire new and exciting research direction in the field of electrochemical sensing. This review covers the latest advances and mechanism of pH-sensing using ZnO nanorods, with an emphasis on the nano-interface mechanism. We discuss methods for calculating the effect of surface states on pH-sensing at a ZnO/electrolyte interface. All of these current research topics aim to explain the mechanism of pH-sensing using a ZnO bulk- or nano-scale single crystal. An important goal of these investigations is the translation of these nanotechnology-modified nanorods into potential novel applications.

  • 12.
    Ali, Bako
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Awad, Ali Ismail
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science. Faculty of Engineering, Al Azhar University.
    Cyber and Physical Security Vulnerability Assessment for IoT-Based Smart Homes2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 3, article id 817Article in journal (Refereed)
    Abstract [en]

    The Internet of Things (IoT) is an emerging paradigm focusing on the connection of devices, objects, or “things” to each other, to the Internet, and to users. IoT technology is anticipated to become an essential requirement in the development of smart homes, as it offers convenience and efficiency to home residents so that they can achieve better quality of life. Application of the IoT model to smart homes, by connecting objects to the Internet, poses new security and privacy challenges in terms of the confidentiality, authenticity, and integrity of the data sensed, collected, and exchanged by the IoT objects. These challenges make smart homes extremely vulnerable to different types of security attacks, resulting in IoT-based smart homes being insecure. Therefore, it is necessary to identify the possible security risks to develop a complete picture of the security status of smart homes. This article applies the operationally critical threat, asset, and vulnerability evaluation (OCTAVE) methodology, known as OCTAVE Allegro, to assess the security risks of smart homes. The OCTAVE Allegro method focuses on information assets and considers different information containers such as databases, physical papers, and humans. The key goals of this study are to highlight the various security vulnerabilities of IoT-based smart homes, to present the risks on home inhabitants, and to propose approaches to mitigating the identified risks. The research findings can be used as a foundation for improving the security requirements of IoT-based smart homes.

  • 13.
    Alirezaie, Marjan
    et al.
    Örebro University, School of Science and Technology.
    Kiselev, Andrey
    Örebro University, School of Science and Technology.
    Längkvist, Martin
    Örebro University, School of Science and Technology.
    Klügl, Franziska
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    An Ontology-Based Reasoning Framework for Querying Satellite Images for Disaster Monitoring2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 11, article id 2545Article in journal (Refereed)
    Abstract [en]

    This paper presents a framework in which satellite images are classified and augmented with additional semantic information to enable queries about what can be found on the map at a particular location, but also about paths that can be taken. This is achieved by a reasoning framework based on qualitative spatial reasoning that is able to find answers to high level queries that may vary on the current situation. This framework called SemCityMap, provides the full pipeline from enriching the raw image data with rudimentary labels to the integration of a knowledge representation and reasoning methods to user interfaces for high level querying. To illustrate the utility of SemCityMap in a disaster scenario, we use an urban environment—central Stockholm—in combination with a flood simulation. We show that the system provides useful answers to high-level queries also with respect to the current flood status. Examples of such queries concern path planning for vehicles or retrieval of safe regions such as “find all regions close to schools and far from the flooded area”. The particular advantage of our approach lies in the fact that ontological information and reasoning is explicitly integrated so that queries can be formulated in a natural way using concepts on appropriate level of abstraction, including additional constraints.

  • 14.
    Alirezaie, Marjan
    et al.
    Örebro University, Sweden.
    Renoux, Jennifer
    Örebro University, Sweden.
    Köckemann, Uwe
    Örebro University, Sweden.
    Kristoffersson, Annica
    Örebro University, Sweden.
    Karlsson, Lars
    Örebro University, Sweden.
    Blomqvist, Eva
    RISE - Research Institutes of Sweden, ICT, SICS.
    Tsiftes, Nicolas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Loutfi, A
    Örebro University, Sweden.
    An ontology-based context-aware system for smart homes: E-care@home2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7, article id 1586Article in journal (Refereed)
    Abstract [en]

    Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

  • 15.
    Alirezaie, Marjan
    et al.
    Örebro University.
    Renoux, Jennifer
    Örebro University.
    Köckemann, Uwe
    Örebro University.
    Kristoffersson, Annica
    Örebro University.
    Karlsson, Lars
    Örebro University.
    Blomqvist, Eva
    SICS East.
    Tsiftes, Nicolas
    SICS.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. SICS.
    Loutfi, Amy
    Örebro University.
    An Ontology-based Context-aware System for Smart Homes: E-care@ home2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7Article in journal (Refereed)
  • 16.
    Alirezaie, Marjan
    et al.
    Örebro University, School of Science and Technology.
    Renoux, Jennifer
    Örebro University, School of Science and Technology.
    Köckemann, Uwe
    Örebro University, School of Science and Technology.
    Kristoffersson, Annica
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Blomqvist, Eva
    RISE SICS East, Linköping, Sweden.
    Tsiftes, Nicolas
    RISE SICS, Stockholm, Sweden.
    Voigt, Thiemo
    RISE SICS, Stockholm, Sweden.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    An Ontology-based Context-aware System for Smart Homes: E-care@home2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7, article id 1586Article in journal (Refereed)
    Abstract [en]

    Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

  • 17.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Renoux, Jennifer
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Köckemann, Uwe
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kristoffersson, Annica
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Karlsson, Lars
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Blomqvist, Eva
    RISE SICS East, Linköping, Sweden.
    Tsiftes, Nicolas
    RISE SICS, Stockholm, Sweden.
    Voigt, Thiemo
    RISE SICS, Stockholm, Sweden.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    An Ontology-based Context-aware System for Smart Homes: E-care@home2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7, article id 1586Article in journal (Refereed)
    Abstract [en]

    Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

  • 18.
    Al-Turjman, Fadi M.
    et al.
    Department of Computer Engineering, Middle East Technical University, Northern Cyprus Campus.
    Imran, Muhammad
    College of Computer and Information Sciences, King Saud University.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Value-Based Caching in Information-Centric Wireless Body Area Networks2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 1, article id 181Article in journal (Refereed)
    Abstract [en]

    We propose a resilient cache replacement approach based on a Value of sensed Information (VoI) policy. To resolve and fetch content when the origin is not available due to isolated in-network nodes (fragmentation) and harsh operational conditions, we exploit a content caching approach. Our approach depends on four functional parameters in sensory Wireless Body Area Networks (WBANs). These four parameters are: age of data based on periodic request, popularity of on-demand requests, communication interference cost, and the duration for which the sensor node is required to operate in active mode to capture the sensed readings. These parameters are considered together to assign a value to the cached data to retain the most valuable information in the cache for prolonged time periods. The higher the value, the longer the duration for which the data will be retained in the cache. This caching strategy provides significant availability for most valuable and difficult to retrieve data in the WBANs. Extensive simulations are performed to compare the proposed scheme against other significant caching schemes in the literature while varying critical aspects in WBANs (e.g., data popularity, cache size, publisher load, connectivity-degree, and severe probabilities of node failures). These simulation results indicate that the proposed VoI-based approach is a valid tool for the retrieval of cached content in disruptive and challenging scenarios, such as the one experienced in WBANs, since it allows the retrieval of content for a long period even while experiencing severe in-network node failures.

  • 19.
    Arain, Muhammad Asif
    et al.
    Örebro University, School of Science and Technology.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Cirillo, Marcello
    Örebro University, School of Science and Technology.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Global coverage measurement planning strategies for mobile robots equipped with a remote gas sensor2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 3, p. 6845-6871Article in journal (Refereed)
    Abstract [en]

    The problem of gas detection is relevant to many real-world applications, such as leak detection in industrial settings and landfill monitoring. In this paper, we address the problem of gas detection in large areas with a mobile robotic platform equipped with a remote gas sensor. We propose an algorithm that leverages a novel method based on convex relaxation for quickly solving sensor placement problems, and for generating an efficient exploration plan for the robot. To demonstrate the applicability of our method to real-world environments, we performed a large number of experimental trials, both on randomly generated maps and on the map of a real environment. Our approach proves to be highly efficient in terms of computational requirements and to provide nearly-optimal solutions.

  • 20.
    Arapan, Lilia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Alexieva, Gergana
    Dept of Solid State Physics and Microelectronics, University of Sofia, Bulgarien.
    Avramov, Ivan D
    Georgy nadjakov Institute of Solid State Physics, Sofia,Bulgarian Academy of Sciences.
    Radeva, Elisaveta
    Georgy Nadjakov Institute of Solid State Physics, Sofia, Bulgarian Academy of Sciences.
    Strashilov, Vesseline
    University of Sofia.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yantchev, Ventsislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)2011In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 11, no 7, p. 6942-6953Article in journal (Refereed)
    Abstract [en]

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  • 21.
    Araujo, Jefferson
    et al.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Reis, Andre
    Observatório Nacional, Brazil.
    Oliveira, Vanderlei
    Observatório Nacional, Brazil.
    Santos, Amanda
    University of California, US.
    Luz-Lima, Cleaneo
    Universidade Federal do Piauí, Brazil.
    Yokoyama, Elder
    University of Brasília, Brazil.
    Mendoza, Leonardo
    Universidade Estadual do Rio de Janeiro, Brazil.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Bruno, Antonio
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Characterizing complex mineral structures in thin sections of geological samples with a scanning hall effect microscope2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 7, article id 1636Article in journal (Refereed)
    Abstract [en]

    We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is located at a distance of 142 µm from the sample; an electromagnet capable of applying up to 500 mT DC magnetic fields to the sample over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce the overall noise in the system; a custom-designed electronics system to bias the sensors and allow adjustments to the background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of 200 µm with a noise at 6.0 Hz of 300 nT rms /(Hz) 1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10 −11 Am 2 . We successfully measured the representative magnetization of a geological sample using an alternative model that takes the sample geometry into account and identified different micrometric characteristics in the sample slice.

  • 22.
    Arvidsson, Daniel
    et al.
    University of Gothenburg, Sweden.
    Fridolfsson, Jonatan
    University of Gothenburg, Sweden.
    Buck, Christoph
    Leibniz Institute for Prevention Research and Epidemiology-BIPS, Bremen, Germany..
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Lissner, Lauren
    University of Gothenburg, Sweden.
    Hunsberger, Monica
    University of Gothenburg, Sweden.
    Börjesson, Mats
    University of Gothenburg, Sweden.
    Reexamination of Accelerometer Calibration with Energy Expenditure as Criterion: VO2net Instead of MET for Age-Equivalent Physical Activity Intensity.2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 15, article id E3377Article in journal (Refereed)
    Abstract [en]

    Accelerometer calibration for physical activity (PA) intensity is commonly performed using Metabolic Equivalent of Task (MET) as criterion. However, MET is not an age-equivalent measure of PA intensity, which limits the use of MET-calibrated accelerometers for age-related PA investigations. We investigated calibration using VO2net (VO2gross - VO2stand; mL⋅min-1⋅kg-1) as criterion compared to MET (VO2gross/VO2rest) and the effect on assessment of free-living PA in children, adolescents and adults. Oxygen consumption and hip/thigh accelerometer data were collected during rest, stand and treadmill walk and run. Equivalent speed (Speedeq) was used as indicator of the absolute speed (Speedabs) performed with the same effort in individuals of different body size/age. The results showed that VO2net was higher in younger age-groups for Speedabs, but was similar in the three age-groups for Speedeq. MET was lower in younger age-groups for both Speedabs and Speedeq. The same VO2net-values respective MET-values were applied to all age-groups to develop accelerometer PA intensity cut-points. Free-living moderate-and-vigorous PA was 216, 115, 74 and 71 min/d in children, adolescents, younger and older adults with VO2net-calibration, but 140, 83, 74 and 41 min/d with MET-calibration, respectively. In conclusion, VO2net calibration of accelerometers may provide age-equivalent measures of PA intensity/effort for more accurate age-related investigations of PA in epidemiological research.

  • 23.
    Asan, Noor Badariah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hassan, Emadeldeen
    Umea Univ, Dept Comp Sci, S-90187 Umea, Sweden;Menoufia Univ, Dept Elect & Elect Commun, Menoufia 32952, Egypt.
    Velander, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Redzwan, Syaiful
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Noreland, Daniel
    Umea Univ, Dept Comp Sci, S-90187 Umea, Sweden.
    Blokhuis, Taco J.
    Maastricht Univ, Med Ctr, Dept Surg, NL-6229 HX Maastricht, Netherlands.
    Wadbro, Eddie
    Umea Univ, Dept Comp Sci, S-90187 Umea, Sweden.
    Berggren, Martin
    Umea Univ, Dept Comp Sci, S-90187 Umea, Sweden.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Augustine, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 9, article id 2752Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7-2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of similar to 0.7 dB and similar to 1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

  • 24.
    Asif, Muhammad H.
    et al.
    COMSATS Institute Informat Technology, Pakistan; Acromed Invest AB, Sweden.
    Danielsson, Bengt
    Acromed Invest AB, Sweden.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    ZnO Nanostructure-Based Intracellular Sensor2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 5, p. 11787-11804Article, review/survey (Refereed)
    Abstract [en]

    Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible. ZnO thus has a wide range of applications in optoelectronics, intracellular nanosensors, transducers, energy conversion and medical sciences. This review relates specifically to intracellular electrochemical (glucose and free metal ion) biosensors based on functionalized zinc oxide nanowires/nanorods. For intracellular measurements, the ZnO nanowires/nanorods were grown on the tip of a borosilicate glass capillary (0.7 mu m in diameter) and functionalized with membranes or enzymes to produce intracellular selective metal ion or glucose sensors. Successful intracellular measurements were carried out using ZnO nanowires/nanorods grown on small tips for glucose and free metal ions using two types of cells, human fat cells and frog oocytes. The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment. Such devices are helpful in explaining various intracellular processes involving ions and glucose.

  • 25.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Thorlin, Thorleif
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Stroke Damage Detection Using Classification Trees on Electrical Bioimpedance Cerebral Spectroscopy Measurements2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 8, p. 10074-10086Article in journal (Refereed)
    Abstract [en]

    After cancer and cardio-vascular disease, stroke is the third greatest cause of death worldwide. Given the limitations of the current imaging technologies used for stroke diagnosis, the need for portable non-invasive and less expensive diagnostic tools is crucial. Previous studies have suggested that electrical bioimpedance (EBI) measurements from the head might contain useful clinical information related to changes produced in the cerebral tissue after the onset of stroke. In this study, we recorded 720 EBI Spectroscopy (EBIS) measurements from two different head regions of 18 hemispheres of nine subjects. Three of these subjects had suffered a unilateral haemorrhagic stroke. A number of features based on structural and intrinsic frequency-dependent properties of the cerebral tissue were extracted. These features were then fed into a classification tree. The results show that a full classification of damaged and undamaged cerebral tissue was achieved after three hierarchical classification steps. Lastly, the performance of the classification tree was assessed using Leave-One-Out Cross Validation (LOO-CV). Despite the fact that the results of this study are limited to a small database, and the observations obtained must be verified further with a larger cohort of patients, these findings confirm that EBI measurements contain useful information for assessing on the health of brain tissue after stroke and supports the hypothesis that classification features based on Cole parameters, spectral information and the geometry of EBIS measurements are useful to differentiate between healthy and stroke damaged brain tissue.

  • 26.
    Atefi, Seyed Reza
    et al.
    Harvard University.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Thorlin, Thorleif
    salhgrenska Hospital.
    Lindecrantz, Kaj
    KTH-School of Technology and Health.
    Stroke Damage Detection Using Classification Trees on Electrical Bioimpedance Cerebral Spectroscopy Measurements2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 8, p. 10074-10086Article in journal (Refereed)
  • 27. Badariah Asan, Noor
    et al.
    Hassan, Emadeldeen
    Umeå University, Faculty of Science and Technology, Department of Computing Science. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Velander, Jacob
    Redzwan Mohd Shah, Syaiful
    Noreland, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Blokhuis, Taco J.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Voigt, Thiemo
    Augustine, Robin
    Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 9, article id 2752Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

  • 28.
    Bagula, Antoine
    et al.
    University of Cape Town.
    Inggs, Gordon
    University of Cape Town.
    Scott, Simon
    University of Cape Town.
    Zennaro, Marco
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    On the Relevance of Using Open Wireless Sensor Networks in Environment Monitoring2009In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 9, no 6, p. 4845-4868Article in journal (Refereed)
    Abstract [en]

    This paper revisits the problem of the readiness for field deployments of wireless sensor networks by assessing the relevance of using Open Hardware and Software motes for environment monitoring. We propose a new prototype wireless sensor network that fine-tunes SquidBee motes to improve the life-time and sensing performance of an environment monitoring system that measures temperature, humidity and luminosity. Building upon two outdoor sensing scenarios, we evaluate the performance of the newly proposed energy-aware prototype solution in terms of link quality when expressed by the Received Signal Strength, Packet Loss and the battery lifetime. The experimental results reveal the relevance of using the Open Hardware and Software motes when setting up outdoor wireless sensor networks.

  • 29.
    Balador, Ali
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Kouba, A.
    Polytechnic Institute of Porto, Porto 4249-015, Portugal.
    Cassioli, D.
    University of L'Aquila, L'Aquila, 67100, Italy.
    Foukalas, F.
    Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
    Severino, R.
    Polytechnic Institute of Porto, Porto 4249-015, Portugal.
    Stepanova, D.
    Finnish Meteorological Institute, 99600 Sodankylä, Finland.
    Agosta, G.
    Politecnico di Milano ,Via G. Ponzio 32, Milano, I-20133, Italy.
    Xie, J.
    Group Technology & Research, DNV GL, Veritasveien 1, Norway.
    Pomante, L.
    University of L'Aquila, L'Aquila, 67100, Italy.
    Mongelli, M.
    CNR-IEIIT ,via De Marini 6, Genova, 16149, Italy.
    Pierini, P.
    Intecs S.p.A., Pisa, 56121, Italy.
    Petersen, S.
    SINTEF ICT, Trondheim, 7465, Norway.
    Sukuvaara, T.
    Finnish Meteorological Institute, 99600 Sodankylä, Finland.
    Wireless Communication Technologies for Safe Cooperative Cyber Physical Systems2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 11, article id 4075Article in journal (Refereed)
    Abstract [en]

    Cooperative Cyber-Physical Systems (Co-CPSs) can be enabled using wireless communication technologies, which in principle should address reliability and safety challenges. Safety for Co-CPS enabled by wireless communication technologies is a crucial aspect and requires new dedicated design approaches. In this paper, we provide an overview of five Co-CPS use cases, as introduced in our SafeCOP EU project, and analyze their safety design requirements. Next, we provide a comprehensive analysis of the main existing wireless communication technologies giving details about the protocols developed within particular standardization bodies. We also investigate to what extent they address the non-functional requirements in terms of safety, security and real time, in the different application domains of each use case. Finally, we discuss general recommendations about the use of different wireless communication technologies showing their potentials in the selected real-world use cases. The discussion is provided under consideration in the 5G standardization process within 3GPP, whose current efforts are inline to current gaps in wireless communications protocols for Co-CPSs including many future use cases.

  • 30.
    Balador, Ali
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS. Mälardalen University, Sweden.
    Kouba, Anis
    Polytechnic Institute of Porto, Portugal.
    Cassioli, Dajana
    University of L’Aquila, Italy.
    Foukalas, Fotis T.
    DTU Technical University of Denmark, Denmark.
    Severino, Ricardo
    Polytechnic Institute of Porto, Portugal.
    Stepanova, Daria
    Finnish Meteorological Institute, Finland.
    Agosta, Giovanni
    Politecnico di Milano, Italy.
    Xie, Jing
    DNV GL, Norway.
    Pomante, Luigi
    DTU Technical University of Denmark, Denmark.
    Mongelli, Maurizio
    CNR-IEIIT, Italy.
    Pierini, Pierluigi
    Intecs S.p.A, Italy.
    Petersen, Stig
    SINTEF, Norway.
    Sukuvaara, Timo
    Finnish Meteorological Institute, Finland.
    Wireless communication technologies for safe cooperative cyber physical systems2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 11, article id 4075Article in journal (Refereed)
    Abstract [en]

    Cooperative Cyber-Physical Systems (Co-CPSs) can be enabled using wireless communication technologies, which in principle should address reliability and safety challenges. Safety for Co-CPS enabled by wireless communication technologies is a crucial aspect and requires new dedicated design approaches. In this paper, we provide an overview of five Co-CPS use cases, as introduced in our SafeCOP EU project, and analyze their safety design requirements. Next, we provide a comprehensive analysis of the main existing wireless communication technologies giving details about the protocols developed within particular standardization bodies. We also investigate to what extent they address the non-functional requirements in terms of safety, security and real time, in the different application domains of each use case. Finally, we discuss general recommendations about the use of different wireless communication technologies showing their potentials in the selected real-world use cases. The discussion is provided under consideration in the 5G standardization process within 3GPP, whose current efforts are inline to current gaps in wireless communications protocols for Co-CPSs including many future use cases.

  • 31.
    Balador, Ali
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Uhlemann, Elisabeth
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Calafate, C. T.
    Universitat Politècnica de València, València, Spain.
    Cano, J. -C
    Universitat Politècnica de València, València, Spain.
    Supporting beacon and event-driven messages in vehicular platoons through token-based strategies2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id 955Article in journal (Refereed)
    Abstract [en]

    Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications. 

  • 32.
    Balador, Ali
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS. Mälardalen University, Sweden.
    Uhlemann, Elisabeth
    Mälardalen University, Sweden.
    Calafate, Carlos T
    Universitat Politècnica de València, Spain.
    Cano, Juan-Carlos
    Universitat Politècnica de València, Spain.
    Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id E955Article in journal (Refereed)
    Abstract [en]

    Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

  • 33.
    Ballesteros, Joaquin
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Tudela, Alberto J.
    University of Malaga, Malaga, Spain.
    Caro-Romero, J. R.
    University of Malaga, Malaga, Spain.
    Urdiales, C.
    University of Malaga, Malaga, Spain.
    Weight-Bearing Estimation for Cane Users by Using Onboard Sensors2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 3Article in journal (Refereed)
    Abstract [en]

    Mobility is a fundamental requirement for a healthy, active lifestyle. Gait analysis is widely acknowledged as a clinically useful tool for identifying problems with mobility, as identifying abnormalities within the gait profile is essential to correct them via training, drugs, or surgical intervention. However, continuous gait analysis is difficult to achieve due to technical limitations, namely the need for specific hardware and constraints on time and test environment to acquire reliable data. Wearables may provide a solution if users carry them most of the time they are walking. We propose to add sensors to walking canes to assess user's mobility. Canes are frequently used by people who cannot completely support their own weight due to pain or balance issues. Furthermore, in absence of neurological disorders, the load on the cane is correlated with the user condition. Sensorized canes already exist, but often rely on expensive sensors and major device modifications are required. Thus, the number of potential users is severely limited. In this work, we propose an affordable module for load monitoring so that it can be widely used as a screening tool. The main advantages of our module are: (i) it can be deployed in any standard cane with minimal changes that do not affect ergonomics; (ii) it can be used every day, anywhere for long-term monitoring. We have validated our prototype with 10 different elderly volunteers that required a cane to walk, either for balance or partial weight bearing. Volunteers were asked to complete a 10 m test and, then, to move freely for an extra minute. The load peaks on the cane, corresponding to maximum support instants during the gait cycle, were measured while they moved. For validation, we calculated their gait speed using a chronometer during the 10 m test, as it is reportedly related to their condition. The correlation between speed (condition) and load results proves that our module provides meaningful information for screening. In conclusion, our module monitors support in a continuous, unsupervised, nonintrusive way during users' daily routines, plus only mechanical adjustment (cane height) is needed to change from one user to another.

  • 34.
    Baloach, Qurrat-ul-Ain
    et al.
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Begum Mallah, Arfana
    University of Sindh, Pakistan.
    Ishaq Abro, Muhammad
    Mehran University of Engn and Technology, Pakistan.
    Uddin, Siraj
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 11, article id 1878Article in journal (Refereed)
    Abstract [en]

    The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template for the evolution of morphology via a rapid and boiled hydrothermal method. The morphology and structure of the synthesized CuO nanomaterial were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The prepared CuO nanostructures showed high potential for use in the electrocatalytic oxidation of glucose in an alkaline medium. The proposed enzyme-free glucose sensor demonstrated a robust response to glucose with a wide linear range and high sensitivity, selectivity, stability, and reproducibility. To explore its practical feasibility, the glucose content of serum samples was successfully determined using the enzyme-free sensor. An analytical recovery method was used to measure the actual glucose from the serum samples, and the results were satisfactory. Moreover, the presented glucose sensor has high chemical stability and can be reused for repetitive measurements. This study introduces an enzyme-free glucose sensor as an alternative tool for clinical glucose quantification.

  • 35.
    Banaee, Hadi
    et al.
    Örebro University, School of Science and Technology.
    Ahmed, Mobyen Uddin
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Data mining for wearable sensors in health monitoring systems: a review of recent trends and challenges2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 12, p. 17472-17500Article in journal (Refereed)
    Abstract [en]

    The past few years have witnessed an increase in the development of wearable sensors for health monitoring systems. This increase has been due to several factors such as development in sensor technology as well as directed efforts on political and stakeholder levels to promote projects which address the need for providing new methods for care given increasing challenges with an aging population. An important aspect of study in such system is how the data is treated and processed. This paper provides a recent review of the latest methods and algorithms used to analyze data from wearable sensors used for physiological monitoring of vital signs in healthcare services. In particular, the paper outlines the more common data mining tasks that have been applied such as anomaly detection, prediction and decision making when considering in particular continuous time series measurements. Moreover, the paper further details the suitability of particular data mining and machine learning methods used to process the physiological data and provides an overview of the properties of the data sets used in experimental validation. Finally, based on this literature review, a number of key challenges have been outlined for data mining methods in health monitoring systems

  • 36.
    Bevilacqua, Fernando
    et al.
    Computer Science, Federal University of Fronteira Sul, Chapecó 89802 112, Brazil.
    Engström, Henrik
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Backlund, Per
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Game-Calibrated and User-Tailored Remote Detection of Stress and Boredom in Games2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 13, p. 1-43, article id 2877Article in journal (Refereed)
    Abstract [en]

    Emotion detection based on computer vision and remote extraction of user signals commonly rely on stimuli where users have a passive role with limited possibilities for interaction or emotional involvement, e.g., images and videos. Predictive models are also trained on a group level, which potentially excludes or dilutes key individualities of users. We present a non-obtrusive, multifactorial, user-tailored emotion detection method based on remotely estimated psychophysiological signals. A neural network learns the emotional profile of a user during the interaction with calibration games, a novel game-based emotion elicitation material designed to induce emotions while accounting for particularities of individuals. We evaluate our method in two experiments (n = 20 and n = 62) with mean classification accuracy of 61.6%, which is statistically significantly better than chance-level classification. Our approach and its evaluation present unique circumstances: our model is trained on one dataset (calibration games) and tested on another (evaluation game), while preserving the natural behavior of subjects and using remote acquisition of signals. Results of this study suggest our method is feasible and an initiative to move away from questionnaires and physical sensors into a non-obtrusive, remote-based solution for detecting emotions in a context involving more naturalistic user behavior and games.

  • 37.
    Burgués, Javier
    et al.
    Institute for Bioengineering of Catalonia (IBEC),The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Marco, Santiago
    Institute for Bioengineering of Catalonia (IBEC),The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
    Smelling Nano Aerial Vehicle for Gas Source Localization and Mapping2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 3, article id 478Article in journal (Refereed)
    Abstract [en]

    This paper describes the development and validation of the currently smallest aerial platform with olfaction capabilities. The developed Smelling Nano Aerial Vehicle (SNAV) is based on a lightweight commercial nano-quadcopter (27 g) equipped with a custom gas sensing board that can host up to two in situ metal oxide semiconductor (MOX) gas sensors. Due to its small form-factor, the SNAV is not a hazard for humans, enabling its use in public areas or inside buildings. It can autonomously carry out gas sensing missions of hazardous environments inaccessible to terrestrial robots and bigger drones, for example searching for victims and hazardous gas leaks inside pockets that form within the wreckage of collapsed buildings in the aftermath of an earthquake or explosion. The first contribution of this work is assessing the impact of the nano-propellers on the MOX sensor signals at different distances to a gas source. A second contribution is adapting the ‘bout’ detection algorithm, proposed by Schmuker et al. (2016) to extract specific features from the derivative of the MOX sensor response, for real-time operation. The third and main contribution is the experimental validation of the SNAV for gas source localization (GSL) and mapping in a large indoor environment (160 m2) with a gas source placed in challenging positions for the drone, for example hidden in the ceiling of the room or inside a power outlet box. Two GSL strategies are compared, one based on the instantaneous gas sensor response and the other one based on the bout frequency. From the measurements collected (in motion) along a predefined sweeping path we built (in less than 3 min) a 3D map of the gas distribution and identified the most likely source location. Using the bout frequency yielded on average a higher localization accuracy than using the instantaneous gas sensor response (1.38 m versus 2.05 m error), however accurate tuning of an additional parameter (the noise threshold) is required in the former case. The main conclusion of this paper is that a nano-drone has the potential to perform gas sensing tasks in complex environments.

  • 38.
    Chang, Keke
    et al.
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Chen, Ruipeng
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Wang, Shun
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Li, Jianwei
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Hu, Xinran
    School of Human Nutrition and Dietetics, McGill University, Canada..
    Liang, Hao
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Cao, Baiqiong
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Sun, Xiaohui
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Ma, Liuzheng
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Zhu, Juanhua
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Jiang, Min
    College of life sciences, Henan Agricultural University, Zhengzhou, China.
    Hu, Jiandong
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China; State key laboratory of wheat and maize crop science, Zhengzhou, China.
    Considerations on Circuit Design and Data Acquisition of a Portable Surface Plasmon Resonance Biosensing System2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 8, p. 20511-20523Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to develop a circuit for an inexpensive portable biosensing system based on surface plasmon resonance spectroscopy. This portable biosensing system designed for field use is characterized by a special structure which consists of a microfluidic cell incorporating a right angle prism functionalized with a biomolecular identification membrane, a laser line generator and a data acquisition circuit board. The data structure, data memory capacity and a line charge-coupled device (CCD) array with a driving circuit for collecting the photoelectric signals are intensively focused on and the high performance analog-to-digital (A/D) converter is comprehensively evaluated. The interface circuit and the photoelectric signal amplifier circuit are first studied to obtain the weak signals from the line CCD array in this experiment. Quantitative measurements for validating the sensitivity of the biosensing system were implemented using ethanol solutions of various concentrations indicated by volume fractions of 5%, 8%, 15%, 20%, 25%, and 30%, respectively, without a biomembrane immobilized on the surface of the SPR sensor. The experiments demonstrated that it is possible to detect a change in the refractive index of an ethanol solution with a sensitivity of 4.99838 × 10(5) ΔRU/RI in terms of the changes in delta response unit with refractive index using this SPR biosensing system, whereby the theoretical limit of detection of 3.3537 × 10(-5) refractive index unit (RIU) and a high linearity at the correlation coefficient of 0.98065. The results obtained from a series of tests confirmed the practicality of this cost-effective portable SPR biosensing system.

  • 39.
    Cheng, Xiaogang
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS). Nanjing Univ Posts & Telecommun, Coll Telecommun & Informat Engn, Nanjing 210003, Jiangsu, Peoples R China.;Umea Univ, Dept Appl Phys & Elect, S-90187 Umea, Sweden.
    Yang, Bin
    Umea Univ, Dept Appl Phys & Elect, S-90187 Umea, Sweden.;Xian Univ Architecture & Technol, Sch Environm & Municipal Engn, Xian 710055, Shaanxi, Peoples R China..
    Liu, Guoqing
    Nanjing Tech Univ, Sch Phys & Math Sci, Nanjing 211800, Jiangsu, Peoples R China..
    Olofsson, Thomas
    Umea Univ, Dept Appl Phys & Elect, S-90187 Umea, Sweden..
    Li, Haibo
    KTH, School of Electrical Engineering and Computer Science (EECS). Nanjing Univ Posts & Telecommun, Coll Telecommun & Informat Engn, Nanjing 210003, Jiangsu, Peoples R China..
    A Total Bounded Variation Approach to Low Visibility Estimation on Expressways2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 2, article id 392Article in journal (Refereed)
    Abstract [en]

    Low visibility on expressways caused by heavy fog and haze is a main reason for traffic accidents. Real-time estimation of atmospheric visibility is an effective way to reduce traffic accident rates. With the development of computer technology, estimating atmospheric visibility via computer vision becomes a research focus. However, the estimation accuracy should be enhanced since fog and haze are complex and time-varying. In this paper, a total bounded variation (TBV) approach to estimate low visibility (less than 300 m) is introduced. Surveillance images of fog and haze are processed as blurred images (pse udo-blurred images), while the surveillance images at selected road points on sunny days are handled as clear images, when considering fog and haze as noise superimposed on the clear images. By combining image spectrum and TBV, the features of foggy and hazy images can be extracted. The extraction results are compared with features of images on sunny days. Firstly, the low visibility surveillance images can be filtered out according to spectrum features of foggy and hazy images. For foggy and hazy images with visibility less than 300 m, the high-frequency coefficient ratio of Fourier (discrete cosine) transform is less than 20%, while the low-frequency coefficient ratio is between 100% and 120%. Secondly, the relationship between TBV and real visibility is established based on machine learning and piecewise stationary time series analysis. The established piecewise function can be used for visibility estimation. Finally, the visibility estimation approach proposed is validated based on real surveillance video data. The validation results are compared with the results of image contrast model. Besides, the big video data are collected from the Tongqi expressway, Jiangsu, China. A total of 1,782,000 frames were used and the relative errors of the approach proposed are less than 10%.

  • 40.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China; School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi'an, China.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A total bounded variation approach to low visibility estimation on expressways2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 2, article id 392Article in journal (Refereed)
    Abstract [en]

    Low visibility on expressways caused by heavy fog and haze is a main reason for traffic accidents. Real-time estimation of atmospheric visibility is an effective way to reduce traffic accident rates. With the development of computer technology, estimating atmospheric visibility via computer vision becomes a research focus. However, the estimation accuracy should be enhanced since fog and haze are complex and time-varying. In this paper, a total bounded variation (TBV) approach to estimate low visibility (less than 300 m) is introduced. Surveillance images of fog and haze are processed as blurred images (pseudo-blurred images), while the surveillance images at selected road points on sunny days are handled as clear images, when considering fog and haze as noise superimposed on the clear images. By combining image spectrum and TBV, the features of foggy and hazy images can be extracted. The extraction results are compared with features of images on sunny days. Firstly, the low visibility surveillance images can be filtered out according to spectrum features of foggy and hazy images. For foggy and hazy images with visibility less than 300 m, the high-frequency coefficient ratio of Fourier (discrete cosine) transform is less than 20%, while the low-frequency coefficient ratio is between 100% and 120%. Secondly, the relationship between TBV and real visibility is established based on machine learning and piecewise stationary time series analysis. The established piecewise function can be used for visibility estimation. Finally, the visibility estimation approach proposed is validated based on real surveillance video data. The validation results are compared with the results of image contrast model. Besides, the big video data are collected from the Tongqi expressway, Jiangsu, China. A total of 1,782,000 frames were used and the relative errors of the approach proposed are less than 10%.

  • 41.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods2012In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, no 11, p. 15063-15077Article in journal (Refereed)
    Abstract [en]

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 x 10(-6) mM to 0.5 x 10(-4) mM, and from 0.5 x 10(-4) mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10(-3) mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

  • 42.
    Cleland, Ian
    et al.
    University of Ulster. School of Computing and Mathematics.
    Kikhia, Basel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Nugent, Chris
    University of Ulster. School of Computing and Mathematics.
    Boytsov, Andrey
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    McClean, Sally
    Computing and Information Engineering, University of Ulster.
    Finlay, Dewar
    University of Ulster. School of Computing and Mathematics.
    Optimal Placement of Accelerometers for the Detection of Everyday Activities2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 7, p. 9183-9200Article in journal (Refereed)
    Abstract [en]

    This article describes an investigation to determine the optimal placement of accelerometers for the purpose of detecting a range of everyday activities. The paper investigates the effect of combining data from accelerometers placed at various bodily locations on the accuracy of activity detection. Eight healthy males participated within the study. Data were collected from six wireless tri-axial accelerometers placed at the chest, wrist, lower back, hip, thigh and foot. Activities included walking, running on a motorized treadmill, sitting, lying, standing and walking up and down stairs. The Support Vector Machine provided the most accurate detection of activities of all the machine learning algorithms investigated. Although data from all locations provided similar levels of accuracy, the hip was the best single location to record data for activity detection using a Support Vector Machine, providing small but significantly better accuracy than the other investigated locations. Increasing the number of sensing locations from one to two or more statistically increased the accuracy of classification. There was no significant difference in accuracy when using two or more sensors. It was noted, however, that the difference in activity detection using single or multiple accelerometers may be more pronounced when trying to detect finer grain activities. Future work shall therefore investigate the effects of accelerometer placement on a larger range of these activities

  • 43.
    Climent, Enric
    et al.
    Sensors and Magnetism Group, Institut de Recerca per a la Gestió Integrada de Zones Costaneres, Campus de Gandia, Universitat Politècnica de València, Grao de Gandia, Spain.
    Pelegri-Sebastia, Jose
    Sensors and Magnetism Group, Institut de Recerca per a la Gestió Integrada de Zones Costaneres, Campus de Gandia, Universitat Politècnica de València, Grao de Gandia, Spain.
    Sogorb, Tomas
    Sensors and Magnetism Group, Institut de Recerca per a la Gestió Integrada de Zones Costaneres, Campus de Gandia, Universitat Politècnica de València, Grao de Gandia, Spain.
    Talens, J. B.
    Sensors and Magnetism Group, Institut de Recerca per a la Gestió Integrada de Zones Costaneres, Campus de Gandia, Universitat Politècnica de València, Grao de Gandia, Spain.
    Chilo, Jose
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Development of the MOOSY4 eNose IoT for Sulphur-Based VOC Water Pollution Detection2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 8, article id E1917Article in journal (Refereed)
    Abstract [en]

    In this paper, we describe a new low-cost and portable electronic nose instrument, the Multisensory Odor Olfactory System MOOSY4. This prototype is based on only four metal oxide semiconductor (MOS) gas sensors suitable for IoT technology. The system architecture consists of four stages: data acquisition, data storage, data processing, and user interfacing. The designed eNose was tested with experiment for detection of volatile components in water pollution, as a dimethyl disulphide or dimethyl diselenide or sulphur. Therefore, the results provide evidence that odor information can be recognized with around 86% efficiency, detecting smells unwanted in the water and improving the quality control in bottled water factories.

  • 44.
    Cruciani, Frederico
    et al.
    Computer Science Research Institute, Ulster University, Newtownabbey BT370QB, UK.
    Cleland, Ian
    Computer Science Research Institute, Ulster University, Newtownabbey BT370QB, UK.
    Nugent, Chris
    Computer Science Research Institute, Ulster University, Newtownabbey BT370QB, UK.
    McCullagh, Paul
    Computer Science Research Institute, Ulster University, Newtownabbey BT370QB, UK.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Automatic annotation for human activity recognition in free living using a smartphone2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 7, article id 2203Article in journal (Refereed)
    Abstract [en]

    Data annotation is a time-consuming process posing major limitations to the development of Human Activity Recognition (HAR) systems. The availability of a large amount of labeled data is required for supervised Machine Learning (ML) approaches, especially in the case of online and personalized approaches requiring user specific datasets to be labeled. The availability of such datasets has the potential to help address common problems of smartphone-based HAR, such as inter-person variability. In this work, we present (i) an automatic labeling method facilitating the collection of labeled datasets in free-living conditions using the smartphone, and (ii) we investigate the robustness of common supervised classification approaches under instances of noisy data. We evaluated the results with a dataset consisting of 38 days of manually labeled data collected in free living. The comparison between the manually and the automatically labeled ground truth demonstrated that it was possible to obtain labels automatically with an 80–85% average precision rate. Results obtained also show how a supervised approach trained using automatically generated labels achieved an 84% f-score (using Neural Networks and Random Forests); however, results also demonstrated how the presence of label noise could lower the f-score up to 64–74% depending on the classification approach (Nearest Centroid and Multi-Class Support Vector Machine).

  • 45.
    Di Lello, Enrico
    et al.
    Div PMA, Dept Mech Engn, Katholieke Univ Leuven, Heverlee, Belgium.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Bruyninckx, Herman
    Div PMA, Dept Mech Engn, Katholieke Univ Leuven, Heverlee, Belgium; , Sect CST, Dept Mech Engn, Eindhoven Univ Technol, Eindhoven, Netherlands .
    De laet, Tinne
    Fac Engn Sci, Katholieke Univ Leuven, Heverlee, Belgium.
    Augmented Switching Linear Dynamical System Model for Gas Concentration Estimation with MOX Sensors in an Open Sampling System2014In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 14, no 7, p. 12533-12559Article in journal (Refereed)
    Abstract [en]

    In this paper, we introduce a Bayesian time series model approach for gas concentration estimation using Metal Oxide (MOX) sensors in Open Sampling System (OSS). Our approach focuses on the compensation of the slow response of MOX sensors, while concurrently solving the problem of estimating the gas concentration in OSS. The proposed Augmented Switching Linear System model allows to include all the sources of uncertainty arising at each step of the problem in a single coherent probabilistic formulation. In particular, the problem of detecting on-line the current sensor dynamical regime and estimating the underlying gas concentration under environmental disturbances and noisy measurements is formulated and solved as a statistical inference problem. Our model improves, with respect to the state of the art, where system modeling approaches have been already introduced, but only provided an indirect relative measures proportional to the gas concentration and the problem of modeling uncertainty was ignored. Our approach is validated experimentally and the performances in terms of speed of and quality of the gas concentration estimation are compared with the ones obtained using a photo-ionization detector.

  • 46.
    Dong, Pingping
    et al.
    College of Information Science and Engineering, Hunan Normal University, Changsha, China. Hunnan Provincial Key Laboratory of Intelligent Computing and Language Information Processing, Hunan Normal University, Changsha, China.
    Gao, Kai
    College of Automotive and Mechanical Engineering, Changsha University of Science & Technology, Changsha 410114, China. Hunan Key Laboratory of Smart Roadway and Cooperative Vehicle-Infrastructure Systems, Changsha, China.
    Xie, Jingyun
    College of Information Science and Engineering, Hunan Normal University, Changsha, China. Hunnan Provincial Key Laboratory of Intelligent Computing and Language Information Processing, Hunan Normal University, Changsha, China.
    Tang, Wensheng
    College of Information Science and Engineering, Hunan Normal University, Changsha, China. Hunnan Provincial Key Laboratory of Intelligent Computing and Language Information Processing, Hunan Normal University, Changsha, China.
    Xiong, Naixue
    College of Intelligence and Computing, Tianjin University, Tianjin, China.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Receiver-Side TCP Countermeasure in Cellular Networks2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 12, article id 2791Article in journal (Refereed)
    Abstract [en]

    Cellular-based networks keep large buffers at base stations to smooth out the bursty data traffic, which has a negative impact on the user’s Quality of Experience (QoE). With the boom of smart vehicles and phones, this has drawn growing attention. For this paper, we first conducted experiments to reveal the large delays, thus long flow completion time (FCT), caused by the large buffer in the cellular networks. Then, a receiver-side transmission control protocol (TCP) countermeasure named Delay-based Flow Control algorithm with Service Differentiation (DFCSD) was proposed to target interactive applications requiring high throughput and low delay in cellular networks by limiting the standing queue size and decreasing the amount of packets that are dropped in the eNodeB in Long Term Evolution (LTE). DFCSD stems from delay-based congestion control algorithms but works at the receiver side to avoid the performance degradation of the delay-based algorithms when competing with loss-based mechanisms. In addition, it is derived based on the TCP fluid model to maximize the network utility. Furthermore, DFCSD also takes service differentiation into consideration based on the size of competing flows to shorten their completion time, thus improving user QoE. Simulation results confirmed that DFCSD is compatible with existing TCP algorithms, significantly reduces the latency of TCP flows, and increases network throughput.

  • 47.
    Du, Jiaying
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Motion Control i Västerås AB, Västerås, Sweden.
    Gerdtman, C.
    Motion Control i Västerås AB, Västerås, Sweden.
    Lindén, Maria
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Signal quality improvement algorithms for MEMS gyroscope-based human motion analysis systems: A systematic review2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id 1123Article in journal (Refereed)
    Abstract [en]

    Motion sensors such as MEMS gyroscopes and accelerometers are characterized by a small size, light weight, high sensitivity, and low cost. They are used in an increasing number of applications. However, they are easily influenced by environmental effects such as temperature change, shock, and vibration. Thus, signal processing is essential for minimizing errors and improving signal quality and system stability. The aim of this work is to investigate and present a systematic review of different signal error reduction algorithms that are used for MEMS gyroscope-based motion analysis systems for human motion analysis or have the potential to be used in this area. A systematic search was performed with the search engines/databases of the ACM Digital Library, IEEE Xplore, PubMed, and Scopus. Sixteen papers that focus on MEMS gyroscope-related signal processing and were published in journals or conference proceedings in the past 10 years were found and fully reviewed. Seventeen algorithms were categorized into four main groups: Kalman-filter-based algorithms, adaptive-based algorithms, simple filter algorithms, and compensation-based algorithms. The algorithms were analyzed and presented along with their characteristics such as advantages, disadvantages, and time limitations. A user guide to the most suitable signal processing algorithms within this area is presented.

  • 48.
    Düking, Peter
    et al.
    University of Würzburg, Würzburg, Germany.
    Achtzehn, Silvia
    German Sport University, Cologne, Germany.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. UiT The Arctic University of Norway, Tromso, Norway.
    Sperlich, Billy
    University of Würzburg, Würzburg, Germany.
    Integrated framework of load monitoring by a combination of smartphone applications, wearables and point-of-care testing provides feedback that allows individual responsive adjustments to activities of daily living2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 5, article id 1632Article in journal (Refereed)
    Abstract [en]

    Athletes schedule their training and recovery in periods, often utilizing a pre-defined strategy. To avoid underperformance and/or compromised health, the external load during training should take into account the individual’s physiological and perceptual responses. No single variable provides an adequate basis for planning, but continuous monitoring of a combination of several indicators of internal and external load during training, recovery and off-training as well may allow individual responsive adjustments of a training program in an effective manner. From a practical perspective, including that of coaches, monitoring of potential changes in health and performance should ideally be valid, reliable and sensitive, as well as time-efficient, easily applicable, non-fatiguing and as non-invasive as possible. Accordingly, smartphone applications, wearable sensors and point-of-care testing appear to offer a suitable monitoring framework allowing responsive adjustments to exercise prescription. Here, we outline 24-h monitoring of selected parameters by these technologies that (i) allows responsive adjustments of exercise programs, (ii) enhances performance and/or (iii) reduces the risk for overuse, injury and/or illness.

  • 49.
    Eklundh, Lars
    et al.
    Lund Univ, Dept Earth & Ecosyst Sci, SE-22362 Lund, Sweden..
    Jin, Hongxiao
    Lund Univ, Dept Earth & Ecosyst Sci, SE-22362 Lund, Sweden..
    Schubert, Per
    Lund Univ, Dept Earth & Ecosyst Sci, SE-22362 Lund, Sweden..
    Guzinski, Radoslaw
    Univ Copenhagen, Dept Geog & Geol, DK-1350 Copenhagen K, Denmark..
    Heliasz, Michal
    Lund Univ, Dept Earth & Ecosyst Sci, SE-22362 Lund, Sweden..
    An Optical Sensor Network for Vegetation Phenology Monitoring and Satellite Data Calibration2011In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 11, no 8, p. 7678-7709Article in journal (Refereed)
    Abstract [en]

    We present a network of sites across Fennoscandia for optical sampling of vegetation properties relevant for phenology monitoring and satellite data calibration. The network currently consists of five sites, distributed along an N-S gradient through Sweden and Finland. Two sites are located in coniferous forests, one in a deciduous forest, and two on peatland. The instrumentation consists of dual-beam sensors measuring incoming and reflected red, green, NIR, and PAR fluxes at 10-min intervals, year-round. The sensors are mounted on separate masts or in flux towers in order to capture radiation reflected from within the flux footprint of current eddy covariance measurements. Our computations and model simulations demonstrate the validity of using off-nadir sampling, and we show the results from the first year of measurement. NDVI is computed and compared to that of the MODIS instrument on-board Aqua and Terra satellite platforms. PAR fluxes are partitioned into reflected and absorbed components for the ground and canopy. The measurements demonstrate that the instrumentation provides detailed information about the vegetation phenology and variations in reflectance due to snow cover variations and vegetation development. Valuable information about PAR absorption of ground and canopy is obtained that may be linked to vegetation productivity.

  • 50.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Incorporating beta-Cyclodextrin with ZnO Nanorods: A Potentiometric Strategy for Selectivity and Detection of Dopamine2014In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 14, no 1, p. 1654-1664Article in journal (Refereed)
    Abstract [en]

    We describe a chemical sensor based on a simple synthesis of zinc oxide nanorods (ZNRs) for the detection of dopamine molecules by a potentiometric approach. The polar nature of dopamine leads to a change of surface charges on the ZNR surface via metal ligand bond formation which results in a measurable electrical signal. ZNRs were grown on a gold-coated glass substrate by a low temperature aqueous chemical growth (ACG) method. Polymeric membranes incorporating beta-cyclodextrin (beta-CD) and potassium tetrakis (4-chlorophenyl) borate was immobilized on the ZNR surface. The fabricated electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The grown ZNRs were well aligned and exhibited good crystal quality. The present sensor system displays a stable potential response for the detection of dopamine in 10(-2) mol.L-1 acetic acid/sodium acetate buffer solution at pH 5.45 within a wide concentration range of 1 x 10(-6) M-1 x 10(-1) M, with sensitivity of 49 mV/decade. The electrode shows a good response time (less than 10 s) and excellent repeatability. This finding can contribute to routine analysis in laboratories studying the neuropharmacology of catecholamines. Moreover, the metal-ligand bonds can be further exploited to detect DA receptors, and for bio-imaging applications.

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