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  • 151.
    Englund, Johan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Determining suitability of the IEEE1609 standard for PRT systems2010Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Personal Rapid Transit systems have high demands on its reliability and security. Many of the fundamental functions needed by a PRT system can be provided by a wireless radio communication link. The goal of this thesis is to determine if the emerging radio standard for intelligent transportation systems is suitable for providing some of the needed functions. The emphasis of this work is to understand the features of the standard that are important for a PRT system and to verify them with simulation.

  • 152.
    Eriksson, Johan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektroteknik, matematik och naturvetenskap.
    Studie av arkitektur för visuellt övervakningssystem vid fjärrstyrt underhåll av järnvägar2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
  • 153.
    Eroglu, Abdullah
    et al.
    Department of Electrical and Computer Engineering, Purdue University Fort Wayne, Fort Wayne, IN, USA..
    Rönnow, Daniel
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Design of multilayer and multiline microstrip directional coupler with closed form relations2018Inngår i: Progress In Electromagnetics Research C, ISSN 1937-8718, E-ISSN 1937-8718, Vol. 83, s. 1-14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Design, simulation, implementation and measurement results of multiline and multilayer microstrip directional couplers are given with closed form relations. Step-by-step design procedure reflecting the design practice of directional couplers, which requires only information on coupling level, port impedances and operational frequency, is presented. The method based on the synthesis technique applied in the design of conventional two-line microstrip symmetrical directional couplers is adapted to design multilayer directional couplers with the aid of electromagnetic simulators using parametric analysis with curve fitting method. The proposed design method is compared with the measurement results and accuracy is verified. It has been also shown that the directivity of the couplers designed using the multilayer structure is improved significantly. A method such as the one presented in this paper can be used to design multilayer two-line and three-line directional couplers which can be integrated to the front end of an RFID systems to provide the required isolation between transmitter and receiver and prevent signal leakage due to use of conventional circulators.

  • 154. Esfeh, Babak Kazemi
    et al.
    Raskin, Jean-Pierre
    Van Moer, Wendy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Low-cost wideband double-layer microstrip coupled-line directional coupler with high directivity2014Inngår i: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 56, nr 7, s. 1570-1575Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, a low-cost double-layer microstrip structure with a gap space between the two substrate layers is used to develop a microstrip coupled-line directional coupler with high directivity. The proposed design shows a high directivity (more than 20 dB) over a wide frequency bandwidth (more than 2 GHz). The double-layer directional coupler, designed on FR4 substrate material at 2.4 GHz provides more than 30 dB isolation. The simulation and measurement results are in good agreement. By applying a simple and low-cost fabrication process and design, the directivity of the directional coupler is enhanced by more than 10 dB compared with a microstrip structure. 

  • 155.
    Fahlström, Tim
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Design av Digital Multimeter-modul för inbyggt testsystem2014Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    The thesis work of 15 credits has been performed to interest of Norrtälje ElektronikPartner AB (NEP) in Norrtälje. The aim of the thesis was to develop a prototype for an integrated digital multimeter, designed for one of NEP's proprietary test systems. A digital multimeter module according to NEP's requirement specification, such as physical size and accuracy should be constructed. The module should be able to measure current, voltage and resistance.

    The final circuit was based on the chosen analog to digital-converter, Maxim integrated´s Max134, which is the main component of the circuit for this instrument. A circuit diagram and PCB layout were made.

     

    The result of this project is a constructed DMM board. During the project's final phase testing, tuning and validation were performed against the established terms of reference. The module was then found to measure current, voltage and resistance according to desired tolerance level.

  • 156.
    Faisal, Yaameen
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Empirical Studies for the Design of Automotive Wireless Sensor Networks2015Independent thesis Advanced level (degree of Master (Two Years)), 80 poäng / 120 hpOppgave
    Abstract [en]

    Nowadays more and more sensors are being incorporated into trucks. All of these sensors are interfaced with the ECU’s using wires. This increases the cost and complexity of installing the sensors. One alternative is to make the connection wireless. Therefore, AB Volvo technologies are researching on how to develop such a system. Currently it is at the initial stages. This thesis is a small part of this research.The main aim of this thesis is to identify the best gateway position for such a wireless sensor network at the chassis of the truck. To achieve this, a test platform was built, tests were performed and empirical link analysis was done. The platform makes use of an open source operating system called Contiki OS and uses IEEE 802.15.4 compliant transceivers. All the tests were conducted on a stationary truck. Moreover, all the tests conducted had 3 variables and they are gateway position, transmission power and truck mode.From the results obtained it was found that 2 gateway positions out of the total 3 tested are equally good. Furthermore, it was found that truck modes didn’t have any impact on the wireless link.

  • 157.
    Fan, Zihao
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö.
    Zhao, Wei
    Högskolan i Gävle, Akademin för teknik och miljö.
    Network Coverage Optimization Strategy in Wireless Sensor Networks Based on Particle Swarm Optimization2011Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    Wireless sensor network is an intelligent network system which has the self-monitoring functionality. It consists of many low-cost, low-power and small-sized sensor nodes that can communicate with each other to perform sensing and data processing. Acting as an important role in the system, network coverage usually has a huge effect on the system’s lifetime.In this thesis, particle swarm algorithm was used as a method to optimize the coverage in the coverage of wireless sensor network. A network coverage optimization strategy based on particle swarm optimization was proposed and MATLAB was used as a tool to apply the algorithm. The model used in this thesis is the probability sensing model and the coverage type is area coverage. Effectiveness of the algorithm is proved by simulation. The simulation of the algorithm suggests the optimal deployment can be determined if a certain parameter which in this thesis is the sensing range is given.

  • 158.
    Faus García, Óscar
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Signal Processing for mmWave MIMO Radar2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis addresses the design study, implementation and analysis of signal processing algorithms for a 79 GHz millimeter-wave Phase Modulated Continuous Wave (PMCW) Multi Input Multi Output (MIMO) short range radar; performed in IMEC research institute (Leuven, Belgium). The radar system targets high resolution performance with low power consumption in order to integrate a full MIMO radar transceiver with digital processor and antennas in a compact package featuring a size of 1 cm2. Achieving such radar system characteristics requires the exploitation of a highly demanding digital architecture with signal processing gain and high range, speed and angle resolutions. The improved resolution and detection capabilities will be achieved by performing signal processing algorithms on the reflected waveform. The digital front-end implements parallel range gate processing with a bank of correlators that perform: pulse compression, coherent accumulation to further increase Signal to Noise Ratio (SNR) and N-point FFT to extract the Doppler information. The use of MIMO is proposed implementing a code domain technique in the PMCW waveform, the Outer Hadamard Code MIMO. This concept makes use of a unique sequence for all the transmitting antennas that is rendered by an outer sequence to ensure the orthogonality of the transmitted waveforms. The outer code makes use of the good cross-correlation properties of the Hadamard sequences and the waveform uses sequences that exhibit perfect auto-correlation profile, the Almost Perfect Autocorrelation Sequences (APAS). The MIMO implementation results in higher angular resolution and extra processing gain. The use of beamforming techniques in the radar allows the angle estimation of the detected targets; using rough and fine beamforming that provides with coarse and precise Angle of Arrival (AoA) estimation in an early and late stage respectively. A Constant False Alarm Rate (CFAR) processing stage is implemented in the stage of the system where higher signal processing gain is achieved. This algorithm allows the variation of the CFAR parameters and analyzes the detections in order to improve the probability of detection (Pd) while decreasing the probability of false alarm (Pfa). A series of simulations with different scenarios and variable parameters are set in order to analyze the performance of the system. The simulations analyze the gain achieved in each stage and their outcomes show an impressive processing gain that can reach SNR improvements as high as 77 dB for a small virtual array while keeping the Pfa low with the CFAR adjustment. The use of bigger arrays demonstrates the possibility to enable clear detections for low Radar Cross Section (RCS) targets in far distances of the unambiguous range. The use of beamforming shows interference reduction improvement as the beam widths narrow with the increasing number of virtual array antennas. These results have been achieved while keeping the system design parameters to a range resolution of 7.5 cm for a maximum range of 37.5 meters with speed resolution of 0.2 m/s and a maximum detectable speed of 12.66 m/s. The outcomes support the good performance of the signal processing techniques implemented and the benefits in applying them in a SoC mmWave MIMO radar.

  • 159.
    Feng, Tianyang
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Studying Noise Contributions in Nonlinear Vector Network Analyzer (NVNA) Measurements2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Noise contribution in nonlinear systems is very different from that in linear systems. The noise effects in nonlinear systems can be complicated and not obvious to predict. In this thesis, the focus was on the noise contribution in nonlinear systems when measuring with the nonlinear vector network analyzer (NVNA). An additional noise source together with a single sinewave signal was fed into the input of the amplifier and the performance was studied. The input power of the amplifier is considered to be the sum of the noise power and the signal power. The variation of the 1 dB compression point and the third order interception point as functions of the added noise power were studied. From the measured results in this thesis, the 1 dB compression point referred to the output power will decrease when increasing the added noise power at the input of the amplifier. The contribution of the added noise to the 1 dB compression point of an amplifier is considered dual: with the added noise the linear regression lines of the AM/AM curves are changed, and due to hard clipping the useful output power is reduced. As a result of those two effects, the added noise made the compression start at a lower power level. When the added noise reaches a certain level, the 1 dB compression point is hard to measure.

    Thus when performing nonlinear measurements, the noise effects should be taken into considerations and further studies are required to get better understanding of the system’s behavior in noisy environment.

  • 160.
    Feng, Xin Mei
    et al.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Olsson, J.
    Centre for Human Studies of Foodstuffs, Uppsala University, Uppsala, Sweden.
    Swanberg, M.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Schnürer, J.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Rönnow, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Image analysis for monitoring the barley tempeh fermentation process2007Inngår i: Journal of Applied Microbiology, ISSN 1364-5072, E-ISSN 1365-2672, Vol. 103, nr 4, s. 1113-1121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: To develop a fast, accurate, objective and nondestructive method for monitoring barley tempeh fermentation. Methods and Results: Barley tempeh is a food made from pearled barley grains fermented with Rhizopus oligosporus. Rhizopus oligosporus growth is important for tempeh quality, but quantifying its growth is difficult and laborious. A system was developed for analysing digital images of fermentation stages using two image processing methods. The first employed statistical measures sensitive to image colour and surface structure, and these statistical measures were highly correlated (r = 0.92, n = 75, P < 0.001) with ergosterol content of tempeh fermented with R. oligosporus and lactic acid bacteria (LAB). In the second method, an image-processing algorithm optimized to changes in images of final tempeh products was developed to measure number of visible barley grains. A threshold of 5 visible grains per Petri dish indicated complete tempeh fermentation. When images of tempeh cakes fermented with different inoculation levels of R. oligosporus were analysed the results from the two image processing methods were in good agreement. Conclusion: Image processing proved suitable for monitoring barley tempeh fermentation. The method avoids sampling, is nonintrusive, and only requires a digital camera with good resolution and image analysis software. Significance and Impact of the Study: The system provides a rapid visualization of tempeh product maturation and qualities during fermentation. Automated online monitoring of tempeh fermentation by coupling automated image acquisition with image processing software could be further developed for process control.

  • 161.
    Ferrer Coll, Javier
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH, Radio Systems Laboratory (RS Lab).
    Channel Characterization and Wireless Communication Performance in Industrial Environments2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The demand for wireless communication systems in industry has grown in recent years. Industrial wireless communications open up a number of new possibilities for highly flexible and efficient automation solutions. However, a good part of the industry refuses to deploy wireless solutions products due to the high reliability requirements in industrial communications that are not achieved by actual wireless systems. Industrial environments have particular characteristics that differ from typical indoor environments such as office or residential environments. The metallic structure and building dimensions result in time dispersion in the received signal. Moreover, electrical motors, vehicles and repair work are sources of electromagnetic interference (EMI) that have direct implications on the performance of wireless communication links. These degradations can reduce the reliability of communications, increasingthe risk of material and personal incidents. Characterizing the sources of degradations in different industrial environments and improving the performance of wireless communication systems by implementing spatial diversity and EMI mitigation techniques are the main goals of this thesis work.

    Industrial environments are generally considered to be environments with a significant number of metallic elements and EMI sources. However, with the penetration of wireless communication in industrial environments, we realize that not all industrial environments follow this rule of thumb. In fact, we find a wide range of industrial environments with diverse propagation characteristics and degradation sources. To improve the reliability of wireless communication systems in industrial environments, proper radio channel characterization is needed for each environment. This thesis explores a variety of industrial environments and attempts to characterize the sources of degradation by extracting representative channel parameters such as time dispersion, path loss and electromagnetic interference. The result of this characterization provides an industrial environment classification with respect to time dispersion and EMI levels, showing the diverse behavior of propagation channels in industry.

    The performance of wireless systems in industrial environments can be improved by introducing diversity in the received signal. This can be accomplished by exploiting the spatial diversity offered when multiple antennas are employed at the transmitter with the possibility of using one or more antennas at the receiver. For maximum diversity gain, a proper separation between the different antennas is needed. However, this separation could be a limiting factor in industrial environments with confined spaces. This thesis investigates the implication of antenna separation on system performance and discusses the benefits of spatial diversity in industrial environments with high time dispersion conditions where multiple antennas with short antenna separations can be employed.

    To ensure reliable wireless communication in industrial environments, all types of electromagnetic interference should be mitigated. The mitigation of EMI requires interference detection and subsequent interference suppression.This thesis looks at impulsive noise detection and suppression techniques for orthogonal frequency division multiplexing (OFDM) based on wide-band communication systems in AWGN and multi-path fading channels. For this,a receiver structure with cooperative detection and suppression blocks is proposed.This thesis also investigates the performance of the proposed receiver structure for diverse statistical properties of the transmitted signal and electromagnetic interference.

  • 162.
    Ferrer Coll, Javier
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH, KTH Center för Trådlösa System, Wireless@kth.
    RF Channel Characterization in Industrial, Hospital and Home Environments2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The rapid development of electronic components has resulted in the emergence of newmobile applications targeted at industry and hospital sectors. Moreover, a lack of availablewireless frequencies as result of the growth of wireless systems is becoming a problem.In this thesis we characterize industrial and hospital environments in order to provide theknowledge necessary to asses present and future development of critical wireless applications.Furthermore, we investigate the possibility of using TV white space by analysingthe interference from secondary to primary user in home environments.

    Some of the wireless solutions used in industries and hospitals come directly fromsystems designed for home or office, such asWLAN and Bluetooth. These systems are notprepared to handle problems associated with interference of impulsive character found inindustrial processes and electrical systems.

    Typically, industrial environments have been classified as reflective environments dueto the metallic structure present in the buildings. In this thesis, we demonstrate that althoughthis may be generally true, some locations in the industry may have special propertieswith wave propagation characteristics in the opposite direction. Stored materials canabsorb wireless signals, resulting in a coverage problem. From the measurement campaignwe are able to distinguish three main classes of indoor environments (highly reflective,medium reflective and low reflective) with different propagation characteristics.

    Improving spectrum efficiency can be a solution to the growing demand for wirelessservices and can increase a system’s robustness against interference, particularly in criticalapplications in industrial and hospital environments. One improvement in spectrum efficiencycan be for secondary consumers to reuse unassigned portions of the TV spectrum ata specific time and geographical location. This thesis studies the effect of inserting whitespace devices in the TV broadcast spectrum. Note that any new model must state the maximumpower allocated to secondary users to avoid harmful interference with the primarysignal.

    The content of this thesis is divided into three parts. The first part is the most comprehensiveand addresses electromagnetic interference and multipath characterization ofindustrial environments. In this part, we have developed a method for channel characterizationfor complex electromagnetic environments and have produced results from differentindustrial environments. The second part presents a preliminary study that characterizesthe electromagnetic interference in a hospital environment. The third part is a study ofsecondary users reusing the TV white spaces.

  • 163.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Slimane, Ben
    KTH.
    Radio-Frequency Electromagnetic Characterization in Factory Infrastructures2012Inngår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 54, nr 3, s. 708-711Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    In recent years, industrial wireless applications have emerged rapidly. The use of short-range radio communication systems in factories increases the flexibility in industrial processes by reducing the use of cables. However, the technological challenges involved in wireless communication in industrial environments are not trivial; they result in disadvantages with respect to reliability and security because of electromagnetic interference. To gain an understanding of the performance limits of these wireless applications, knowing the characteristics of these environments is essential. In this approach, amplitude probability distribution and rms delay spread measurements have been used to perform electromagnetic site surveys in three factory automation infrastructures.

  • 164.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. School of Information and Communication Technology, KTH Royal Institute of Technology, Kista, Sweden.
    Choquehuanca, Juan José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    Swedish Defence Research Agency, P.O. Box 1165, SE-58111, Sweden.
    Statistical Characterization of the Electromagnetic Environment in a Hospital2010Inngår i: 2010 Asia-Pacific Symposium on Electromagnetic Compatibility, APEMC 2010, 2010, s. 293-296, artikkel-id 5475847Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Thanks to advances in digital technology many hospitals are becoming populated with wireless medical applications to control life critical functions. Electromagnetic interference can cause severe performance degradations on these wireless applications. Several accidents have been reported which calls for a more thorough characterization of these interferences in areas where critical wireless applications are used. In this paper the results of electromagnetic interference measurements performed in a hospital are presented. The amplitude probability distribution (APD) and the inter arrival pulse probability distribution (PSD) are used to characterize these environments. In addition, Middleton parameters can be calculated from the measured data. This study is considered to be a first effort to characterize the 20 MHz -2500 MHz band in hospitals.

  • 165.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH.
    Dolz Martin de Ojeda, Jose
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. FOI.
    Marzal Romeu, Silvia
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Industrial Indoor Environment Characterization: Propagation Models2011Inngår i: Proceedings of EMC Europe 2011 York - 10th International Symposium on Electromagnetic Compatibility, 2011, s. 245-249Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Results of three years' field measurements on radio propagation in industrial environments have been analyzed using four propagation models: the Saleh-Valenzuela model, the twocluster model, the indoor power delay profile model, and our more recent adjusted model. In this study, we used the results of measurements performed at a steel mill, a paper mill, and in a laboratory environment for three frequency bands (183-683 MHz, 1640-2140 MHz, and 2200-2700 MHz) and for line-of-sight and non-line-of-sight cases.

  • 166.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Karlsson, Carl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    FOI.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Ultra-Wideband Propagation Channel-Measurements and Simulations in Industrial Environments2010Inngår i: 9th International Symposium on EMC joint with 20th International Wroclaw Symposium on EMC, 2010, s. 615-618Konferansepaper (Fagfellevurdert)
  • 167.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH, School of Information and Communication Technology, Kista, Sweden .
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. FOI.
    Industrial environment characterization for future M2M applications2011Inngår i: Proc. 2011 IEEE International Symposium on Electromagnetic Compatibility, New York: IEEE conference proceedings, 2011, s. 960-963Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Combining electronics, telecommunications, and information technology to connect devices and remote systems is perhaps the best feature of the future Machine-to-Machine (M2M) technology. Wireless communication technologies for managing future M2M applications are becoming mature, but electromagnetic interference and time dispersion in industrial environments can limit the successful functioning of these wireless systems, leading to a failure in the control of critical functions. The characterization of these environments is necessary for collecting and specifying M2M requirements. In this paper, we present the conclusions from measurements carried out in four different industrial environments during the past three years.

  • 168.
    Ferrer Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. School of Information and Communication Technology, KTH Royal Institute of Technology, Sweden.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Karlsson, Carl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. Swedish Defence Research Agency, Sweden.
    Simulation and Measurement of Electromagnetic Radiation Absorption in a Finished-product Warehouse2010Inngår i: IEEE International Symposium on Electromagnetic Compatibility, 2010, s. 881-884, artikkel-id 5711396Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Several studies have characterized industrial environments as being highly reflective. In this paper, we provide the data obtained from electromagnetic field measurements performed at the warehouse of a paper mill. The data is also compared to simulated data. This data proves the existence of non-reflective and very high absorption industrial environments where wireless communication is impossible at certain frequencies. Furthermore, in such environment, radio performance cannot be improved by multiple antenna solutions such as MIMO (Multiple Input Multiple Output) since multiple reflections are effectively absorbed.

  • 169.
    Ferrer Martínez, Claudia
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Machine Learning for Solar Energy Prediction2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis consists of the study of different Machine Learning models used to predict solar power data in photovoltaic plants.

    The process of implement a model of Machine Learning will be reviewed step by step: to collect the data, to pre-process the data in order to make it able to use as input for the model, to divide the data into training data and testing data, to train the Machine Learning algorithm with the training data, to evaluate the algorithm with the testing data, and to make the necessary changes to achieve the best results.

    The thesis will start with a brief introduction to solar energy in one part, and an introduction to Machine Learning in another part. The theory of different models and algorithms of supervised learning will be reviewed, such as Decision Trees, Naïve Bayer Classification, Support Vector Machines (SVM), K-Nearest Neighbor (KNN), Linear Regression, Logistic Regression, Artificial Neural Network (ANN).

    Then, the methods Linear Regression, SVM Regression and Artificial Neural Network will be implemented using MATLAB in order to predict solar energy from historical data of photovoltaic plants. The data used to train and test the models is extracted from the National Renewable Energy Laboratory (NREL), that provides a dataset called “Solar Power Data for Integration Studies” intended for use by Project developers and university researchers. The dataset consist of 1 year of hourly power data for approximately 6000 simulated PV plants throughout the United States.

    Finally, once the different models have been implemented, the results show that the technique which provide the best results is Linear Regression.

  • 170.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden .
    Slimane, Ben
    School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden .
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden; Department of Electrical Engineering (ISY), Linköping University, Linköping, Sweden .
    Detection and Suppression of Impulsive Noise in OFDM Receiver2015Inngår i: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 85, nr 4, s. 2245-2259Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years, the use of wireless systems in industrial applications has experienced spectacular growth. Unfortunately, industrial environments often present impulsive noise which degrades the reliability of wireless systems. OFDM is an enhanced technology used in industrial communication to monitor the work and movement of employees using high quality video. However, OFDM is sensitive to high amplitude impulsive noise because the noise energy spreads among all OFDM sub-carriers. This paper proposes a receiver structure consisting of two stages: a detector stage combining Fisher’s Quadratic discriminant and Gaussian Hypothesis techniques, and a suppression stage optimized by setting well defined thresholds. The receiver structure has been tested by simulations and measurements providing an increment in the probability of detection and improving the system performance.

  • 171.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH.
    Slimane, Ben
    KTH.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    FOI.
    Impulsive noise detection in OFDM systems with PAPR reduction2014Inngår i: 2014 International symposium on electromagnetic compatibility (EMC Europe), IEEE conference proceedings, 2014, s. 523-527Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Impulsive noise is a major source of degradation in industrial communications. Orthogonal frequency-division multiplexing (OFDM) is an extended technique used in many industrial communications, however the performance of OFDM systems is reduced under an impulsive noise source. To increase the system performance, impulsive noise detection and suppression techniques can be designed in the communication system. OFDM has high levels of peak-to-average power ratio (PAPR), thus PAPR reduction techniques, such as selected mapping (SLM), are implemented in OFDM systems. This paper proposes an impulsive noise detection exploiting the statistical properties of the OFDM envelope when applying SLM. The proposed detection technique increases the probability of detection and improves the BER of the communication system compared to other impulsive detection techniques.

  • 172.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    FOI.
    Characterisation of electromagnetic properties in iron-mine production tunnels2012Inngår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 48, nr 2, s. 62-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modern underground mines require reliable wireless communication for transmitting voice data, operating surveillance cameras, and monitoring mining equipment such as heavy vehicles. The electromagnetic characteristics of mines therefore have to be considered when determining the type of wireless technology for such critical applications. In this reported work, measurements of radio interference levels, path loss, and multipath propagation are performed in the world's now largest iron ore mine, situated in Sweden, to determine a suitable wireless technology for this mine.

  • 173.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    FOI, Totalförsvarets forskningsinstitut.
    Characterisation of highly absorbent and highly reflective radio wave propagation environments in industrial applications2012Inngår i: IET Communications, ISSN 1751-8628, E-ISSN 1751-8636, Vol. 6, nr 15, s. 2404-2412Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experience has shown that Bluetooth, Wireless LAN (WLAN), Digital Enhanced Cordless Telecommunications (DECT) and other Industrial, Scientific and Medical (ISM) frequency band wireless technologies developed for office use, have encountered problems when used in critical industrial applications. The development of more reliable wireless solutions requires extensive knowledge of industrial environments with regards to both electromagnetic interference and wave propagation. This study presents the results of the analysis of two important classes of industrial environments having opposite characteristics, one being highly absorbent and the other being highly reflective, with respect to radio wave propagation. The analysis comprises both multipath and path loss characterisation. The results show that wireless solutions with different fundamental properties must be chosen for each of these environments to ensure high reliability. The conclusions of this work can be used as an important reference for further research in this area, as well as the design of new standards and guidelines for selecting wireless solutions in similar industrial environment classes.

  • 174.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Elofsson, Carl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. FOI.
    Antenna Cross Correlation and Ricean K-Factor Measurements in Indoor Industrial Environments at 433 and 868 MHz2013Inngår i: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 73, nr 3, s. 587-593Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Ricean K-factor and antenna diversity properties for indoor industrial environments have been characterized for 433 and 868 MHz. The high amount of metallic structures gives a multipath environment that heavily differs from other environments e.g. indoor office environments. The results show that low correlation between receiving antennas can be achieved for shorter antenna distances than in other environments.

  • 175.
    Ferrer-Coll, Javier
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Ängskog, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Shabai, He
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. FOI, Totalförsvarets forskningsinstitut and Linköping University.
    Analysis of wireless communications in underground tunnels for industrial use2012Inngår i: 38TH ANNUAL CONFERENCE ON IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2012), New York: IEEE conference proceedings, 2012, s. 3216-3220Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Wireless communication is expected to improve the safety and the productivity in underground tunnels for industrial use. However the multiple shapes and structures of tunnels affect wireless communication characteristics in terms of signal propagation which is significantly different from terrestrial environments. This paper presents comprehensive broadband measurements and simulations of multipath propagation and path loss in two underground environments. The results can be used in the development of new communication systems in tunnels that provide industrial services.

  • 176.
    Flattery, Kyle
    et al.
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA.
    Amin, Shoaib
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. ACCESS Linnaeus Centre, Signal Processing Dept, KTH Royal Institute of Technology, Stockholm, Sweden.
    Mahamat, Yaya
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA..
    Eroglu, Abdullah
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA..
    Rönnow, Daniel
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    High Power Combiner/Divider Design for Dual Band RF Power Amplifiers2015Inngår i: Proceedings of the 2015 International Conference on Electromagnetics in Advanced Applications: ICEAA 2015, IEEE Press, 2015, s. 1036-1039Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Design of low loss with an enhanced thermal profile power divider/combiner for high power dual-band Radio Frequency (RF) power amplifier applications is given. The practical implementation, low loss and substrate characteristics make this type of combiner ideal for high power microwave applications. The combiner operational frequencies are chosen to operate at 900 MHz and 2.14 GHz, which are common frequencies for concurrent dual band RF power amplifiers. The analytical results are verified with simulation results for various cases and agreement has been observed on all of them.

  • 177.
    Fors, K.M.
    et al.
    Swedish Def Res Agcy, Linkoping, Sweden.
    Wiklundh, K.C.
    Swedish Def Res Agcy, Linkoping, Sweden.
    Stenumgaard, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. Swedish Def Res Agcy, Linkoping, Sweden.
    Improved impulsiveness correction factor for controlling electromagnetic interference in dynamic spectrum access applications2010Inngår i: IET Communications, ISSN 1751-8628, Vol. 4, nr 4, s. 437-442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Initiatives to open certain frequency bands for dynamic spectrum access (DSA) are ongoing. Examples are the wireless access policy for electronic communications services and white spaces coalition. A key issue in DSA is how to measure occupancy and interference in an open frequency band to decide whether or not it can be used for a certain service. Such measurement must be easy to perform and provide a result that can be used as decision metric. An earlier proposal, based on a so-called impulsiveness correction factor, with this purpose has been shown to work properly if the interference is dominated by a single pulsed signal. In this study, the former approach is extended to the case in which the interference signal consists of a multiple of interference signals. This extension is shown as a closed expression involving only parameters that can be determined from an interference measurement.

  • 178.
    Fraile, F
    et al.
    Universidad Politécnica de Valencia.
    Nader, Charles
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Guerri, J. C.
    Universidad Politécnica de Valencia.
    Björsell, Niclas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    On the reuse of DVB-T transmitter infrastructure for DVB-T22011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The new DVB-T2 standard was specifically designed to allow the reuse of DVB-T infrastructure if required. This paper presents measurement results that verify the correct performance of a commercial DVB Power Amplifier with DVB-T2 waveforms. Furthermore, the paper includes configuration guidelines and performance evaluation of the Tone Reservation PAPR reduction algorithm included in the DVB-T2 standard. PAPR reduction is key technology when reusing DVB-T amplifiers for DVB-T2 transmissions without penalizing amplifier efficiency.

  • 179.
    Frances Galiana, Alfredo
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    PERFORMANCE ANALYSIS OF DUTY-CYCLE MAC PROTOCOLS IN WIRELESS SENSOR NETWORKS2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis studies the behavior of the S-MAC protocol in a Wireless Sensor Networks (WSN). The main limitation of the WSN is the lifetime of the battery, because normally it is short and it is not possible to change it all the time. For this reason, the battery consumption and the delay have to be low. This reduction of delay can be done with the medium access control (MAC) protocol duty-cycle in the sensors. For decrease the energy consumption, sensors must be set in an appropriate way following some rules, such as: how many packets the sensor send at the same time, how much time the sensor has to be awake if it does not transmit, how to transmit with less collisions, if retransmission of packets are good or not for the system... The main phenomenon with the greatest impact on the waste of energy is the Idle Listening. It refers to the time a node is awake listening to the medium when the transmitted packets are not addressed to it. This fact produces great energy losses.

    Among duty-cycle MAC protocols, some of them are synchronous (all the nodes wake up at the same time) and other protocols are asynchronous (each node wake up at different time). My contribution will be especially for synchronous model but also it is dedicated a small part of the time for analyzed the asynchronous model. Although there are several synchronous models, my work is focused in an SMAC protocol because it is the commonly used. For create the simulation system, it has kept in mind a system located in a forest with the goal of preventing fires (for this environment, it will be desired to have very low delay and also, that the system works well for the entire range of the arrival rate).

    The investigation is done by simulation, which allows to study realistic deployment scenarios. Simulations will be done in a C simulation program and the results will be treated with Matlab. All the work will be based on stochastic processes that typically appear in real deployment scenarios.

  • 180.
    Fritzin, Jonas
    et al.
    Ericsson AB; Linköpings universitet.
    Alvandpour, Atila
    Linköpings universitet.
    Landin, Per
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. Chalmers.
    Fager, Christian
    Chalmers.
    Linearity, intermodulation distortion and ACLR in outphasing amplifiers2013Inngår i: 2013 IEEE MTT-S International Microwave Symposium Digest, IEEE conference proceedings, 2013, artikkel-id 6697584Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The distortion from amplitude and phase imbalance in outphasing amplifiers is discussed. The relation between dynamic range (DR) and suppression of distortion is shown to approximately follow a simple linear relationship depending on the DR. Approximate relations between adjacent channel leakage power ratio (ACLR) for different kinds of commonly used communication signals and two-tone intermodulation distortion are given. Relations between loss in output power and reduction of DR as functions of duty cycle in switching-based outphasing amplifiers are also given. An approximate method to evaluate the possible performance of digital pre-distortion (DPD) is also given by considering a DPD capable of correcting all distortions except amplitude imbalance. The predicted performance is compared to the performance obtained using a DPD-model found in the literature. The results show that the method is in good agreement, demonstrating that the proposed method can be used for design and evaluation of predistorted outphasing amplifiers. 

  • 181.
    Fritzin, Jonas
    et al.
    Linköping University.
    Jung, Ylva
    Linköping University.
    Landin, Per Niklas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Händel, Peter
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Enqvist, Martin
    Linköping University.
    Alvandpour, Atila
    Linköping University.
    Phase predistortion of a class-D outphasing RF amplifier in 90 nm CMOS2011Inngår i: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 58, nr 10, s. 642-646Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This brief presents a behavioral model structure and5a model-based phase-only predistortion method that are suitable for outphasing RF amplifiers. The predistortion method is based on a model of the amplifier with a constant gain factor and phase rotation for each outphasing signal, and a predistorter with phase rotation only. The method has been used for EDGE and wide-band code-division multiple-access (WCDMA) signals applied to a Class-D outphasing RF amplifier with an on-chip transformer used for power combining in 90-nm CMOS. The measured peak power at 2 GHz was +10.3 dBm with a drain efficiency and power-added efficiency of 39% and 33%, respectively. For an EDGE 8 phase-shift-keying (8-PSK) signal with a phase error of 3 degrees between the two input outphasing signals, the measured power at 400 kHz offset was −65.9 dB with predistortion, compared with −53.5 dB without predistortion. For a WCDMA signal with the same phase error between the input signals, the measured adjacent channel leakage ratio at 5-MHz offset was -50.2 dBc with predistortion, compared with -38.0 without predistortion.

  • 182.
    Fu, Xubo
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Characterization of NI-USRP System2014Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    Nowadays the rapid developments of wireless communication technologies there are more and more

    ways to look into the RF measurements and designs in detail such as Universal Software Radio

    Peripheral(USRP) from LabVIEW, Advance Design System(ADS),etc.Moreover a lack of

    measurements what compared with different digital modulation schemes is becoming a problem. In

    this thesis by building the simulations of communication system in NI-USRP system and measuring

    the results then compare with the different PSK system in order to give a deeper insight of this new

    software of USRP from LabVIEW. and in the end analyze bit error rate varus signal to noise ratio

    from the PSK system.

    To get the characterizations of NI-USRP system the first step is to build multiple simulations such as

    FM receiver, PSK wireless communication systems. By performing the FM receiver is to analyze the

    quality of the receiving and baseband FM signal. And from the simulation of different PSK

    communications through the analysis of the performance of BPSK,QPSK,OQPSK and compared with

    bit error rate it could give an insight of characterization of NI-USRP system and in the end the

    conclusions give in which kind of prototype or simulation that suit the best of NI-USRP system.

  • 183.
    Gaddam, Nagavenkat kumar
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    BLUETOOTH / ZIGBEE NETWORKS AND DEVELOPMENT OF PORTABLE 6LOWPAN STACK2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless sensor networks (WSN’s) are becoming popular in military and civilian applications such as surveillance, monitoring, disaster recovery, home automation and many others. Prolonged network lifetime, scalability, node mobility and load balancing are important requirements for many WSN applications.

    This thesis work presents the investigation of scalability and power consumption in different wireless module such as Bluetooth, Zigbee to deploy in the large scale wireless sensor network application by simulation the network topologies, analysis and comparison of both the wireless module in OPNET and running the WSN application using Zigbee in Real environment.

    In order to increase the scalability and reduce the power consumption we use the Internet protocol version 6 (IPv6) over Low Power Wireless Personal Area Network (6LoWPAN), we worked on the programming of the 6LoWPAN protocol stack and analysis of the results using the perytons network protocol analyzer. 

     

  • 184.
    Gao, Min
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö.
    Liu, Zijia
    Högskolan i Gävle, Akademin för teknik och miljö.
    Real-time Spectrum Analyzer Light2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Real-time spectrum analyzer is a hot instrument for signal analysis and spectrum monitoring. It has wide applications in wireless communication and high potential for smart reading. However, it is characterized with a high cost. Hence, a designed light version based on already available lab instruments is constructed for use in school lab. In this thesis, a simple oscilloscope and a computer were used in the process. Both instruments communicated through GPIB cable and MATLAB software was used for the processing tasks. In order to test the designed one, a simple signal generator was used. The signal was analyzed in both time domain and frequency domain. Then measurements of the signal over time were updated to a matrix of FFT and were plotted in 3D, showing spectrum variation over time. The application of this project to radio frequency analysis was also discussed.

  • 185.
    Ghahfarokhi, Sohil Shahabi
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Prasad, Sathyaveer
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Tayari, Danial
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Impact of Moisture Content on RFID Antenna Performance for Wood-Log Monitoring2011Inngår i: RFMTC11, Gävle, Sweden, 2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In recent years, the use of RFID technology has gained popularity in the timber industry for wood-log monitoring. Harvested wood-logs are stored for different time periods before being processed. As a result, the moisture content in the stored wood-logs varies compared to the freshly-cut wood and it must also be noted that the moisture content of freshly cut wood differs from one log to another. Apart from storage time period of wood-logs, the environmental factors such as temperature, rain, snow and sun also contributes to the variation in the moisture content of the wood-logs. This variation of the moisture content changes the dielectric constant of the wood and hence, influences the characteristics of the RFID antenna. In this paper the impact of variations in moisture content in wood and its effect on the performance of the RFID antenna are studied.

  • 186.
    Glans, Mikael
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Utveckling av styrsystem för EMC-kammare2009Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis aims to develop a control system for measuring electromagnetic compability (EMC). This has meant that a controller designed around an ATmega8 microcontroller has been manufactured and programmed. It has also meant the development of a comprehensive control software in the program MATLAB. The control system has been tested with satisfactory results and can now, monitor and control measurements of the EMC-type.

  • 187. Glazunov, Andres Alayon
    et al.
    Prasad, Sathyaveer
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH.
    Händel, Peter
    Bolin, Thomas
    Prytz, Kjell
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Fysik.
    Impact of Scattering Within a Multipath Simulator Antenna Array on the Ricean Fading Distribution Parameters in OTA Testing2014Inngår i: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 62, nr 6, s. 3257-3269Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate the unwanted scattering that exists within the multipath simulator (MPS) array antennas employed in over the air (OTA) testing of mobile terminals. The impact of scattering is evaluated in terms of the measurement uncertainty of the average received power and the Ricean K-factor. The maximum ratio combining diversity is investigated for a generic device under test comprising two half-wavelength dipole antennas. We provide closed-form expressions for the uncertainties of the average received power and the Ricean K-factor for a uniform circular array of MPS antennas and a 2-D uniformly distributed angle-of-arrival spectrum. We also derive the maximum number of MPS antennas and the minimum ring radius of the MPS system as a function of the separation between the most distant antenna elements if the device under test employs a uniform linear array. As a result, we provide design guidelines for MPS array in terms of the number antennas, the radius of the MPS array and the wavelength of the carrier frequency.

  • 188.
    Gong, Pu
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Guo, Hua
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Post-Correction of Analog to Digital Converters2008Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    As the rapid development of the wireless communication system and mobile video devices, the integrated chip with low power consuming and high conversion efficiency is widely needed. ADC and DAC are playing an important role in these applications.

    The aim of this thesis is to verify a post-correction method which is used for improving the performance of ADC. First of all, this report introduces the development and present status of ADC, and expatiate its important parameters from two different classes (static performance and dynamic performance). Based on the fundamental principle, the report then focuses on the dynamic integral non-linearity modeling of ADC. Refer to this model, one post-correction method is described and verified.

    Upon the face of post-correction, this method is to modify the output signals which have been converted from analog to digital format by adding a correction term. Improvement made by the post-correction needs to be checked out. Thus the performance analysis mainly relay on the measures of total harmonic distortion and signal to noise and distortion ratio is also included in this thesis.

  • 189.
    Gonzales Fuentes, Lee
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    HELPING COGNITIVE RADIO IN THE SEARCH FOR FREE SPACE2012Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    Spectrum sensing is an essential pre-processing step of cognitive radio technology for dynamic radio spectrum management. One of the main functions of Cognitive radios is to detect the unused spectrum and share it without harmful interference with other users. The detection of signal components present within a determined frequency band is an important requirement of any sensing technique. Most methods are restricted to the detection of the spectral lines. However, these methods may not comply with the needs imposed by practical applications. 

    This master thesis work presents a novel method to detect significant spectral components in measured non-flat spectra by classifying them in two groups: signal and noise frequency lines. The algorithm based on Fisher’s discriminant analysis, aside from the detection of spectral lines, estimates the magnitude of the spectral lines and provides a measure of the quality of classification to determine if a spectral line was incorrectly classified. Furthermore, the frequency lines with higher probability of misclassification are regrouped and the validation process recomputed, which results in lower probabilities of misclassification.

    The proposed automatic detection algorithm requires no user interaction since any prior knowledge about the measured signal and the noise power is needed. The presence or absence of a signal regardless of the shape of the spectrum can be detected. Hence, this method becomes a strong basis for high-quality operation mode of cognitive radios.

    Simulation and measurement results prove the advantages of the presented technique. The performance of the technique is evaluated for different signal-to-noise ratios (SNR) ranging from 0 to -21dB as required by the IEEE standard for smart radios. The method is compared with previous signal detection methods.

  • 190.
    Gonzales Fuentes, Lee
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap. Vrije Universiteit Brussel.
    Barbe, Kurt
    Vrije Universiteit Brussel.
    Van Moer, Wendy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. Vrije Universiteit Brussel.
    Björsell, Niclas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Cognitive radios: discriminant analysis finds the free space2012Inngår i: 2012 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), New York: IEEE conference proceedings, 2012, s. 2242-2247Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Spectrum sensing is an essential pre-processing step for cognitive radio technology. This paper presents a novel method to detect the significant spectral components in measured nonflat spectra, and to estimate the magnitude of the spectral components. Furthermore, the probability that the spectral component was incorrectly classified is available. The algorithm is able to detect the presence or absence of signals in any kind of spectrum since no prior knowledge about the measured signal is needed. Hence, this method becomes a strong basis for a high-quality operation mode of cognitive radios. Simulation results prove the advantages of the presented technique.

  • 191. Gonzales-Fuentes, L.
    et al.
    Barbé, K.
    Van Moer, Wendy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Adaptive noise tracking for Cognitive Radios under more realistic operation conditions2014Inngår i: IEEE Instrumentation and Measurement Technology Conference, 2014, s. 1339-1344Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Normal operation conditions of cognitive radio applications require signal processing techniques that can be executed in real time. One of the first steps is to sense the occupied or free frequency channels. Two major drawbacks in the current techniques are that they assume (i) the noise as white and (ii) the measured spectrum as time-invariant. In real world, the noise is (i) colored so it disturbs the signal unevenly and (ii) its spectrum changes over time. Hence, tracking the time-varying noise spectrum can become crucial to remove the noise contributions and enhance the estimate of the received signal. In this paper, we study an auto-regressive model to develop an adaptive noise tracking technique using a Kalman filter such that an extension of Boll's noise subtraction technique, designed for audio noise cancellation, becomes feasible when adjusted to cognitive radio scenarios. Simulation results show the performance of this technique. 

  • 192.
    Gonzales-Fuentes, Lee
    et al.
    Vrije Universiteit Brussel.
    Barbe, Kurt
    Vrije Universiteit Brussel.
    Van Moer, Wendy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. Vrije Universiteit Brussel.
    Björsell, Niclas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Cognitive Radios: Discriminant Analysis for Automatic Signal Detection in Measured Power Spectra2013Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 62, nr 12, s. 3351-3360Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Signal detection of primary users for cognitive radios enables spectrum use agility. In normal operation conditions, the sensed spectrum is nonflat, i.e., the power spectrum is not constant. A novel method proposes the segmentation of the measured spectra into regions where the flatness condition is approximately valid. As a result, an automatic detection of the significant spectral components together with an estimate of the magnitude of the spectral component and a measure of the quality of classification becomes available. In this paper, we optimize the methodology for signal detection in cognitive radios such that the probability that a spectral component was incorrectly classified is iteratively reduced. Simulation and measurement results show the advantages of the presented technique in different types of spectra.

  • 193.
    Granqvist, C. G.
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Azens, A.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Kullman, L.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Progress in Smart Windows Research: Improved Electrochromic W Oxide Films and Transparent Ti-Ce Oxide Counter Electrodes1996Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 8, nr 1-4, s. 97-106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We review recent work on sputter deposited W-oxide-based films. Improved electrochemical durability was obtained by electron bombardment during deposition, and enhanced coloration/bleaching dynamics was obtained by fluorination. Spectrally resolved scattering measurements indicated that haze levels ≪ 1 % could be reached. Oblique angle deposition could yield angular selectivity. New results are given for sputtered Ti-Ce oxide films, showing their capacity as counter electrodes in transparent electrochromic devices.

  • 194.
    Granqvist, C.-G.
    et al.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Azens, A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Hjelm, A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Kullman, Lisen
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Niklasson, Gunnar A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Strömme, Maria
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Veszelei, M.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Vaivars, G.
    Institute of Solid State Physics, University of Latvia, Riga, Latvia.
    Recent advances in electrochromics for smart windows applications1998Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 63, nr 4, s. 199-216Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Electrochromic smart windows are able to vary their throughput of radiant energy by low-voltage electrical pulses. This function is caused by reversible shuttling of electrons and charge balancing ions between an electrochromic thin film and a transparent counter electrode. The ion transport takes place via a solid electrolyte. Charge transport is evoked by a voltage applied between transparent electrical conductors surrounding the electrochromic film/electrolyte/counter electrode stack. This review summarizes recent progress concerning: (i) calculated optical properties of crystalline WO3, (ii) electrochromic properties of heavily disordered W oxide and oxyfluoride films produced by reactive magnetron bias sputtering, (iii) novel transparent reactively sputter-deposited Zr-Ce oxide counter electrodes and (iv) a new proton-conducting antimonic-acid-based polymer electrolyte. Special in depth presentations are given on elastic light scattering from W-oxide-based films and of electronic band structure effects affecting opto-chronopotentiometry data in Zr-Ce oxide. The review also contains some new device data for an electrochromic smart window capable of very high optical transmittance.

    Electrochromic smart windows are able to vary their throughput of radiant energy by low-voltage electrical pulses. This function is caused by reversible shuttling of electrons and charge balancing ions between an electrochromic thin film and a transparent counter electrode. The ion transport takes place via a solid electrolyte. Charge transport is evoked by a voltage applied between transparent electrical conductors surrounding the electrochromic film/electrolyte/counter electrode stack. This review summarizes recent progress concerning: (i) calculated optical properties of crystalline WO3, (ii) electrochromic properties of heavily disordered W oxide and oxyfluoride films produced by reactive magnetron bias sputtering, (iii) novel transparent reactively sputter-deposited Zr-Ce oxide counter electrodes and (iv) a new proton-conducting antimonic-acid-based polymer electrolyte. Special in depth presentations are given on elastic light scattering from W-oxide-based films and of electronic band structure effects affecting opto-chronopotentiometry data in Zr-Ce oxide. The review also contains some new device data for an electrochromic smart window capable of very high optical transmittance.

  • 195.
    Gupta, Ashta
    et al.
    Department of Electronics and Communication, ASET, Amity University Uttar Pradesh Noida, India.
    Tripathy, Malay Ranjan
    Department of Electronics and Communication, ASET, Amity University Uttar Pradesh Noida, India.
    Choudhary, Vipin
    Department of Electronics and Communication, ASET, Amity University Uttar Pradesh Noida, India.
    Rönnow, Daniel
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    A compact four-element MIMO antenna for WLAN/WiMAX and HiperLAN applications2016Inngår i: 2016 IEEE Annual India Conference (INDICON), 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A compact four-element multi-input-multi-output (MIMO) antenna useful for wireless ultra-wide band (UWB) applications and systems is introduced in this paper. The frequency bandwidth obtained with the proposed UWB antennas is 1.5 to 12.5 GHz. The substrate material used is FR4 with dielectric coefficient of 4.4. The dimension of the substrate is 30×60×1.5 mm3 and the dielectric loss tangent is 0.02. The Envelope Correlation Coefficient (ECC) and Diversity gain are calculated in this paper with values within their acceptable limits.

  • 196.
    Gutierrez Saenz, Juan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy analysis and cost estimation of a potential On-shore Power Supply system in the Port of Gävle2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The Port of Gävle is one of the most important harbours in Sweden as far as size and freight capacity is concerned. Marine traffic is increasing greatly, thus environmental pollution as well as noise and vibrations are of major concern in port cities. Shore to ship power supply systems might be a feasible solution to curtail emissions because the Auxiliary Engines are instead shut down while the ship stays alongside the quay. The literature review shows they are reliable and very appealing in all respects, thereby contributing to sustainable development. Taking into account the kind of vessels that call at the Port of Gävle, a High Voltage Shore Connection is recommendable, in compliance with the International Standards. An own technical survey is developed to gather all the information, as well as personal interviews to collect first-hand data. Technical issues such as the synchronisation procedure and the ground system with regard to safety are briefly discussed. Due to the lack of data, calculations consist of average values: peak and average demand, and fuel consumption during a typical call. Considering updated energy prices for both electricity and fuel, results show that an on‑shore power supply system make energy costs decrease by 71% at berth in comparison with burning marine fuel, which is saved by around 4 tonnes per call. Additionally, up to 5126 tonnes of CO2 are avoided per year, among other pollutants. Shore‑side power has proven to be profitable and appealing to the Port of Gävle; however, vessels need to be retrofitted, which implies relatively high investments. Collaboration agreements and shipping companies’ willingness to undergo changes are key issues that still need to be solved.

  • 197.
    Guttke, Dennis
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Design och konstruktion av trådlöst sensornätverk för mätning av inomhusmiljö2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Tillfredsställande inomhusmiljö är idag mycket viktigt eftersom människor spenderar majoriteten av sin tid inomhus. För att fastställa och reglera inomhusmiljön måste denna mätas. Detta sker med olika sensorer och de vanligaste är koldioxid-, kolmonoxid-, temperatur- och luftfuktighetssensorer. Mätsystem som idag mäter inomhusmiljö är dyra att köpa in och att installera. Dessutom varierar de i svårighetgrad att konfigurera. Med hjälp av billig elektronik och trådlösa sensornätverk kan den totala kostnaden, inte minst installationskostnader, reduceras eftersom radiolänkar utnyttjas istället för kabelbunden kommunikation. Trådlösa sensornätverk kan även underlätta konfigurering av mätsystemet om ändringar behöver göras. Denna studie beskriver design och konstruktion av ett trådlöst sensornätverk för mätning av infraljud, koldioxidhalt, temperatur och relativ luftfuktighet. Bristen på mätsystem som mäter inomhusmiljö där infraljud är en av mätparametrarna gör det önskvärt att mäta infraljud istället för en av de andra vanliga mätparametrarna. I studien konstrueras en sensornod, en gateway och PC programvara. Utvärdering och test av konstruerat system utförs och resultaten jämförs mot ett referenssystem. Resultaten visar att mätsystemet i jämförelse med ett referenssystem ger tillfredsställande resultat. Avvikelserna mellan systemen är liten. Resultat från infraljudsmätningarna visar att mätsystemet kan mäta infraljudnivå men behöver filtreras för att återge korrekta signalnivåer.

  • 198.
    Haider, Ammar
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Design of a metal detector2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Electromagnetic wave propagation is a well-known phenomenon in the scientific world and when the first telescope was built method of sensing objects excelled afterwords. Research in optical system and infrared is growing day by day but radar system still dominates the world in object sensing. One of the benefits of using electromagnetic waves in a Radar system is that they can create images of areas which cannot be observed with optical light. Radars work on the basic phenomena of an extremely short burst of radio energy which transmit energy that reflects from the object as an echo. This principle is also known as ECHO Principal [13].

    This thesis presents a Coffee Can radar system which gives detection of a stationary and moving object. Objects detection is performed on the oscilloscope using a triangular wave transmitted from an antenna, that gets reflected from an object and received on the second antenna. The prototype consists of two antennas one of which is used for transmitting signal and other is used for receiving signal. Voltage control oscillator is used to generate the RF frequency signal and power amplifiers are used before transmitting and receiving the RF signal. The signals are down-converted using a mixer the output of which is observed on an oscilloscope. Detection of the reflected signal can be performed using Doppler shift which can be determined from the velocity of electromagnetic radiation and angular displacement of the reflected waves. The wavelength of the Doppler shift is then used to indicate the detection and ranging of the object.

    Coffee Can radar operates at 2.4GHz with the output power of 10mW. Triangular wave signal is generated with the help of a wave generator. The radar prototype built in this thesis is used for detection and ranging of two different types of materials. First, is a metal sheet and secondly an aluminum foil.  The detection process is completed by noting the Vpp values reflected from these sheets. Vpp values are measured on the oscilloscope when the signal reflected from aluminum sheet. With the help of a commercial software, aluminum foil presence is detected under the snow.

    For the future work if the video amplifier is built then the aluminum foil presence can be detected on MATLAB without the help of any commercial software. In future Coffee Can Radar can also be used for surveillance purposes like smart homes, autonomous vehicles and as a jammer. This Radar system can also be used as a data logging system.   

  • 199.
    Haider, Usama
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektroteknik, matematik och naturvetenskap.
    Smart Maintenance using System Identification2019Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This project discusses the use of System Identification for Smart Maintenance. System Identification is the process of finding a mathematical model of a system using empirical data. The mathematical model can then be used to detect and predict the maintenance needs, which is considered as Smart Maintenance. Smart maintenance strategies have gained pretty much importance recently, since it contributes to economically sustainable production. This project uses the LAVA-framework, proposed in [1] for non-linear system identification, which has the capability of explaining the dynamics of the system very well, and at the same time follows the principle of parsimony. A nominal model is first identified using data from a system that operates under normal operating conditions, then the identified nominal model is used to detect when the system starts to deviate from normal behavior, and these deviations indicate the deteriorations in the system. Furthermore, a new Multiple Model Method which is developed in [2] using the similar idea from LAVA, is applied on the large data set of a system that operates on separate batches and units, which identifies individual model for each batch and unit, which is then used to detect the deficient units or batches and changes in the system behavior. Finally, the proposed methods are applied to two different real world industrial cases; a Heat exchanger and a Wood Moulder Machine. In the first, the purpose is to detect the dirt in a Heat Exchanger, and in the second, the goal is to detect when the tool in a Wood Moulder Machine needs to be changed.

  • 200.
    Haider, Usman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. University Polytechnic Cartagena, Spain.
    Nyoman, Indrawibawa I.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. University Polytechnic Cartagena, Spain.
    Coronado, Juan Lopez
    University Polytechnic Cartagena, Spain.
    Kim, Chanki
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    Virk, Gurvinder S.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik.
    User-centric Harmonized Control for Single Joint Assistive Exoskeletons2016Inngår i: International Journal of Advanced Robotic Systems, ISSN 1729-8806, E-ISSN 1729-8814, Vol. 13, nr 3, artikkel-id 115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The world is ageing and this poses a challenge to produce cost-effective solutions that can keep elderly people independent and active by assisting them in daily living activities. In this regard, this paper presents a new control method to provide physical assistance for any of the user joints (e.g., hip, knee, elbow, etc.) as needed by the wearer, by means of an assistive non-medical single joint exoskeleton with a "harmonized controller" capable of providing assistance in a natural way, and varying the assistance as needed by the user performing some activity. The control method is aimed at exoskeletons to provide assistance to users facing difficulty in any activity such as walking, sit-to-stand, etc., and, other than providing assistance as needed, it can also reduce the muscular effort for a completely healthy user. Harmonized control uses exoskeleton-integrated force sensors and motion sensors to identify the user's intentions and the assistance level required, generating appropriate control signals for the actuators by implementing a simple PID controller. To verify the proposed harmonized-control technique, simulations using MATLAB/SIMULINK were performed for a single joint system. An experimental test rig for a single joint was also developed using MATLAB Xpc Target for real-time control. User tests were also carried out for the knee joint and the results obtained from simulations, experimentation and user tests are reported and discussed here. The results achieved to date and reported here show harmonized control to be a promising user-centric solution for the development of single joint assistive exoskeletons for support as needed by the user in daily living activities.

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