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  • 1.
    Abbas, Syed Haider
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Enhancement of Viterbi Decoder2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 2.
    Abou Raas, Mhd Jihad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Wall Compensation Algorithms for M-sequence UWB Radar2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A technique for wall compensation in the ultra-wideband (UWB) through-wall imaging radar is presented. The UWB system can be utilize in high precision measurements, but due to phase distortion and amplitude attenuation caused by the wall the precision is limited, the target is displaced, and the image is defocused. 

    In order to mitigate the wall effects, two methods are applied in this project. First, the unknown wall transfer function is estimated using real data measurements to design the inverse filter. Secondly, FIR Wiener filter is designed to improve the received m-sequence. After all, each method is tested using three parameters, the signal to noise ratio (SNR), the signal to clutter ratio (SCR), and the relative position error (RPE). 

    The inverse filter can eliminate the wall effects very well; it could correct not only the position of the target but also the image defocus. The new method can give improve the image quality and that can extend the use of UWB radar in many applications. 

  • 3. Aboul-Ata, Aboul-Ata E.
    et al.
    Vitti, Antonella
    Nuzzaci, Maria
    El-Attar, Ahmad K.
    Piazzolla, Giuseppina
    Tortorella, Cosimo
    Harandi, Ali M.
    Olson, Olof
    Wright, Sandra A. I.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Piazzolla, Pasquale
    Plant-Based Vaccines: Novel and Low-Cost Possible Route for Mediterranean Innovative Vaccination Strategies2014In: Advances in Virus Research / [ed] Maramorosch, K; Murphy, F A, Elsevier, 2014, Vol. 89, 1-37 p.Chapter in book (Refereed)
    Abstract [en]

    A plant bioreactor has enormous capability as a system that supports many biological activities, that is, production of plant bodies, virus-like particles (VLPs), and vaccines. Foreign gene expression is an efficient mechanism for getting protein vaccines against different human viral and nonviral diseases. Plants make it easy to deal with safe, inexpensive, and provide trouble-free storage. The broad spectrum of safe gene promoters is being used to avoid risk assessments. Engineered virus-based vectors have no side effect. The process can be manipulated as follows: (a) retrieve and select gene encoding, use an antigenic protein from GenBank and/or from a viral-genome sequence, (b) design and construct hybrid-virus vectors (viral vector with a gene of interest) eventually flanked by plant-specific genetic regulatory elements for constitutive expression for obtaining chimeric virus, (c) gene transformation and/or transfection, for transient expression, into a plant host model, that is, tobacco, to get protocols processed positively, and then moving into edible host plants, (d) confirmation of protein expression by bioassay, PCR-associated tests (RT-PCR), Northern and Western blotting analysis, and serological assay (ELISA), (e) expression for adjuvant recombinant protein seeking better antigenicity, (f) extraction and purification of expressed protein for identification and dosing, (g) antigenicity capability evaluated using parental or oral delivery in animal models (mice and/or rabbit immunization), and (h) growing of construct-treated edible crops in protective green houses. Some successful cases of heterologous gene-expressed protein, as edible vaccine, are being discussed, that is, hepatitis C virus (HCV). R9 mimotope, also named hypervariable region 1 (HVR1), was derived from the HVR1 of HCV. It was used as a potential neutralizing epitope of HCV. The mimotope was expressed using cucumber mosaic virus coat protein (CP), alfalfa mosaic virus CP P3/RNA3, and tobacco mosaic virus (TMV) CP tobacco mild green mosaic virus (TMGMV) CP as expression vectors into tobacco plants. Expressed recombinant protein has not only been confirmed as a therapeutic but also as a diagnostic tool. Herpes simplex virus 2 (HSV-2), HSV-2 gD, and HSV-2 VP16 subunits were transfected into tobacco plants, using TMV CP TMGMV CP expression vectors.

  • 4.
    Abrego peris, Iñaki
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Antenna with medical applications for tumour cancer: hyperthermia function2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The idea is to improve or help the treatments that exist in the market in the medical field. Treatments such as mammography or radiotherapy make use of X-rays. X-rays are electromagnetic radiation in a high frequency band, this type of electromagnetic is dangerous to health because ionizing radiation is used, ionized atoms interact with matter. For this reason, in our work we give alternative solution to these treatments without any risk to health. This project consists in the use of non-harmful frequencies such as microwave. In this way, we will make an antenna with medical applications whose frequency range will be between 300 MHz and 30 GHz, specifically between 950MHz and 2.45GHz (medical range). The first step will be the detection of the tumour and classification of this, but our work is about another technique called hyperthermia. This technique consists in increase the temperature with a value of 40-43 degrees in the tumour area. Tumour resistance decreases when heat is applied to this. When combining a treatment with oncologic hyperthermia, the effect of radiotherapy is most effective (between 1.5-5 times). The most important part is study antenna in body tissues characteristics as SAR, depth penetration and antenna size; this theory part is essential to know the best parameters and what case use this. In work development we will choose and design antennas for the different parts of the body in some specific frequencies and choose circular antennas in frequencies of 915 MHz and 1.8 GHz. Finally, we will take measurements about temperature increase with meat and say some conclusions.

  • 5.
    Adis, Kurtalic
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Linkfire2011Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Planen var att konstruera en PCI-Express-till-PCI brygga för fyra MoCA radiokort. Problem uppstod då det visade sig att PLC8112 inte kunde hantera fyra PCI samtidigt som var utlovat från tillverkaren av bryggan. För att lösa problemet fick PCI6152 läggas till i designen. Det är en PCI-till-PCI brygga som också ska klara att hantera upp till fyra PCI enligt tillverkaren. Fyra MoCA radiokort förbrukar mycket ström. Två spänningsregulatorer lades till i designen för att kunna leverera de strömmar som krävs. För att säkerställa att radiokorten som ansluts till Linkfire inte blir för varma så placeras en temperatursensor under ett radiokort. Temperatursensorn har endast av/på lägen och till den ansluts två fläktar, därmed så betraktas dem som en fläkt då de inte är individuellt styrda.

  • 6.
    Afzal, Nauman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10nal@student.hig.se.
    Udata, Ramakrishna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10rua@student.hig.se.
    Designing and measurement of routing module for transceiver system at 3.125GHz2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This report intends to impart a good understanding of routing modules used in modern transceiver systems. The radar system at RadarBolaget AB needed to have a good routing module for its newly designed transceiver antenna. In this report, studies have been done related to two majorly used routing modules in modern electronics industry; Microwave Circulator and RF/Microwave Switch. First off, different characteristics of routing modules are discussed. After having discussed important design parameters, practical design considerations for two routing modules are presented in a profound way. Theoretical knowledge for both of these two devices is presented in the beginning, followed by their practical designs using standard simulation software like HFSS and ADS. The report concludes its findings in a way that at the end of this report, reader becomes acquainted with ample information to be able to choose the best option available among all of the discussed designs. An FET RF Switch is chosen at the end of this project to be used for transceiver system which should be able to satisfy specifications specified by RadarBolaget AB. This project was carried out by two students of Master Program in Electronics/Telecommunications at Högskolan i Gävle in collaboration with RadarBolaget AB, Gävle, Sweden.    

  • 7.
    Ahlbom, Håkan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Nordlander, Edvard
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Why choose a technical career?2010In: Socio-cultural and Human Values in Science and Technology Education / [ed] Slavko Dolinšek, Terry Lyons, Ljubljana, Slovenia: IRI UL , 2010Conference paper (Refereed)
    Abstract [en]

     

    Technology is a neglected mandatory subject in the Swedish compulsory school. The subject is supposed to inspire young people to consider a technical career, due to an increasing need for engineers and a declining recruitment to engineering education.

    An investigation of influential factors for choosing a technical career is presented. The factors are well-known, but the relative impact of the factors is investigated using questionnaires and semi-structured interviews with engineering students. Special focus is put on the effect of previous technical schooling. The most important factors for choosing technical education are personal technical interest, future salary expectations, and personal qualities.

  • 8.
    AHMAD, FAHEEM
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    KAKKERLA, PRAMOD
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    FOCUSING OF UWB RADAR SIGNALS USING TIME REVERSAL2013Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Focusing techniques and detection of targets is usually associated to defense and military use. However in recent past things have moved ahead. Now target detection using UWB radars is being done in many industries and corporations. Radarbolaget AB is one of them; one of their projects uses UWB radars to detect steel strips inside a furnace. This research solves a potential problem of detecting middle steel strip out of total three strip edges which can be seen by radar placed on the front. For better understanding of the reader, existing system and introductory UWB radar principles are discussed. As there can be many solutions to focusing of targets here (steel strip edge detection). Available focusing techniques have been discussed in detail along with the possible physical and simulation setups. Later in the document, detection methods have been proposed. UWB time reversed signal detection is a fairly new method and a very limited research has been done so far. PRBS sequence has been focused on in detection mechanism. Results section show that the pulse of the PRBS works better and produces more promising results rather than a repetitive signal. Time reversal methods for locating the target have been used to find the approximate location of the target. Manual distance calculations from target to the transmitter and receiver have been done. Comparison of actual distance from target to the transmitter is compared with simulation results. Different model simulation setups and their results have proved that using UWB Time reversed signals; a still or moving target can be detected with centimeter window precision.

  • 9.
    Ahmed Mohamed Ahmed, Mazz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Traffic Model Based Energy Efficient Radio Access Network2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As the concerns about global energy consumption increased the matter of energy consumption in Radio Access Networks (RANs) became an important issue especially with the exponential growth in demanded traffic. This interest of developing innovative technologies to reduce the expected energy consumption by the mobile communication sector was driven by environmental concerns and cost reduction.

    The aim of this thesis is to introduce a new methodology to make the Radio Access Network (RAN) more energy efficient based on jointly the demanded throughput and a realistic traffic profile. Furthermore, to find a metric that quantifies the relation between the Energy Efficiency (EE), Spectrum Efficiency (SE) and demanded throughput.

    The proposed methodology for reducing the energy consumption in the RAN characterizes the offered throughput in order to determine the sufficient energy needed. The manner for reducing the energy consumed by the RAN is simply by switching (OFF/ON) Base Stations (BSs) based on the demanded throughput which introduces an energy efficient RAN.

    The results show a significant reduction in the energy consumption with regard to the demanded traffic. Moreover, it gives a measure of the EE with consideration to the SE which enhances the performance evaluation from an EE point of view during the RAN planning phase.

  • 10.
    Ahmed, Motasim
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Radarbolaget AB.
    Single-Layer Metamaterial Absorber for Radar Application2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the radar systems, the crosstalk or antenna-to-antenna interference between the radar antennas is useful in some cases. However in some application the received signal is too weak such as wall crack detection and it might affect the accuracy of the radar system. The aim of this thesis is to design, fabricate and test a single layer metamaterial absorber operates from 1 GHz to 4 GHz. The metamaterial absorber can be used as a barrier between the antennas or even in the antenna housing in order to reduce or prevent the antenna-to-antenna interference.

    The method used to fulfill the goal is to shift the frequency response of a known structure by changing the dimension to the wanted band. The software HFSS used to design and simulate the proposed structure which made of L-shaped copper placed diagonally over a substrate separating it from a continuous copper plane. The simulation results exhibit a wideband absorption response of 2.42 GHz ranging from 1.9 GHz to 4.32 GHz. The structure has been simulated over the dimension variation to investigate the flexibility and sensitivity of the designed single layer structure.

    The fabricated metamaterial absorber measured over the direct incident waves. The structure reveals a wideband absorption response of 1.69 GHz ranging from 2.23 GHz up to 3.92 GHz with more than 90% absorptivity. The structure also exposed that the response of the structure starts to create two bands within the wanted band by increasing the angle of the incident waves. 10° polarization angle gives more than 80% absorptivity response. 

  • 11.
    Al Amin, A.
    et al.
    Department of EEE, Uttara University, Dhaka, Bangladesh.
    Islam, M.
    Department of EEE, Uttara University, Dhaka, Bangladesh.
    Masud, M. A.
    Department of EEE, Uttara University, Dhaka, Bangladesh.
    Khan, N. H.
    Department of EEE, Uttara University, Dhaka, Bangladesh.
    Zavala, J. W. A.
    Characterization Engineer, Radio Semiconductor Corporation, Netherlands.
    Islam, M. M. U.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Design and performance analysis of 3.4 ghz rectangular microstrip patch antenna for wireless communication systems2017In: International Journal on Communications Antenna and Propagation, ISSN 2039-5086, E-ISSN 2039-5094, Vol. 7, no 1, 80-86 p.Article in journal (Refereed)
    Abstract [en]

    Wireless communication provides low-cost, high-speed and flexible communication in present days. Hence antenna plays a vital role in the wireless communication sector. The main concern of this paper is therefore to design a 3.4 GHz rectangular Microstrip patch antenna. Moreover, the feed probe based rectangular patch antenna will be designed. The performance of the designed rectangular patch antenna will be evaluated by analysing the major parameters of the simulation results. Hence the radiation pattern, gain, impedance matching and reflection coefficient or return loss calculation will be executed by the HFSS software to evaluate the performance of the antenna. 

  • 12.
    Alayón Glazunov, Andrés
    et al.
    Division of Electromagnetic Engineering, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Prasad, Sathyaveer
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Signal Processing Lab, KTH Royal Institute of Technology, Stockholm, Sweden.
    Händel, Peter
    ACCESS Linnaeus Centre; Signal Processing Lab, KTH Royal Institute of Technology, Stockholm, Sweden.
    Experimental Characterization of the Propagation Channel along aVery Large Virtual Array in a Reverberation Chamber2014In: Progress in Electromagnetics Research B, ISSN 1937-6472, E-ISSN 1937-6472, Vol. 59, 205-217 p.Article in journal (Refereed)
    Abstract [en]

    We show that the combined use of radio frequency absorbers and directive antennas can produce significant changes of the radio propagation channel properties along the positions of a virtual array inside a reverberation chamber. A multidimensional characterization of the channel was performed at 40 antenna positions with spacing of 0:233λ at 1 GHz. The average power, the Ricean K-factor, the coherence bandwidth, the r.m.s. delay spread, the mean delay, the beamforming power angle spectrum and array antenna correlation have been studied for different arrangements in the reverberation chamber. The analysis shows that the joint average over time and frequency channel behavior is, as expected, rather homogeneous along the very large array. However, individual realizations of the channel present a pronounced selective behavior in space, time and frequency with parameters varying along the positions of the virtual array suggesting that a heterogeneous behavior of the radio channels can be emulated in reverberation chambers. An important application of the presented study comprises testing of antenna array designs and algorithms in multipath environments. Further development may lead to Over The Air testing of Multiple Input Multiple Output antenna systems of various sizes, i.e., from small to very large arrays.

  • 13.
    Alfaro Zavala, Juan Wilfredo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Improving Error Performance in Bandwidth-Limited Baseband Channels2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Channel coding has been largely used for the purpose of improving error performance on a communications system. Typical methods based on added redundancy allow for error detection and correction, this improvement however comes at a cost of bandwidth. This thesis focuses on channel coding for the bandwidth-limited channel where no bandwidth expansion is allowed.

    We first discuss the idea of coding for the bandwidth-limited channel as seen from the signal space point of view where the purpose of coding is to maximize the Euclidian distance between constellation points without increasing the total signal power and under the condition that no extra bits can be added. We then see the problem from another angle and identify the tradeoffs related to bandwidth and error performance.

    This thesis intends to find a simple way of achieving an improvement in error performance for the bandwidth-limited channel without the use of lattice codes or trellis-coded modulation.

    The proposed system is based on convolutional coding followed by multilevel transmission. It achieved a coding gain of 2 dB on Eb/No or equivalently, a coding gain of approximately 2.7 dB on SNRnorm without increase in bandwidth. This coding gain is better than that obtained by a more sophisticated lattice code Gosset E8 at the same error rate.

  • 14.
    Alizadeh, Mahmoud
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Royal Institute of Technology, Stockholm, Sweden.
    Amin, Shoaib
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Royal Institute of Technology, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Measurement and analysis of frequency-domain Volterra kernels of nonlinear dynamic 3x3 MIMO systems2017In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 66, no 7, 1893-1905 p.Article in journal (Refereed)
    Abstract [en]

    Multiple-input multiple-output (MIMO) frequency-domain Volterra kernels of nonlinear order 3 are experimentally determined in bandwidth-limited frequency regions. How the effect of higher nonlinear orders can be reduced and how this affects the estimated errors are discussed. The magnitude and phase of the kernels areKramers-Kronig consistent. The self- and cross-kernels have different symmetries and the kernels are therefore determined and analyzed in different regions in the 3D frequency space. By analyzing the properties along certain paths in the 3D frequency space, the block structures for the respective kernels are determined. These block structures contain the significant blocks of the general block structures for third-order kernels. The device under test is a MIMO transmitter for radio frequency signals.

  • 15.
    Alizadeh, Mahmoud
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Department of Signal Processing, ACCESS Linnaeus Center, The Royal Institute of Technology (KTH), Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    A two-tone test for characterizing nonlinear dynamic effects of radio frequency amplifiers in different amplitude regions2016In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 89, 273-279 p.Article in journal (Refereed)
    Abstract [en]

    A new two-tone test method for radio frequency power amplifiers is presented. The test signal is a two-tone probing-signal superimposed on large-signals of different amplitude. The amplifier is, thus, excited in different amplitude regions. The amplitude and phase of the 3rd order intermodulation (IM) products are measured vs. frequency spacing and probing-signal amplitude in each region. The IM magnitude is a measure of the nonlinearity, while the frequency dependence and asymmetry are measures of the memory effects in the different regions. A Doherty and a class-AB amplifier were tested. For both amplifiers the IM magnitude increased by ∼15 dB from the lowest to the highest amplitude region. For the Doherty amplifier the behavior of the IM products vs. frequency spacing was similar in all regions, indicating similar memory effects. For the class-AB amplifier the IM vs. frequency spacing was significantly different in the different regions, which indicates different memory effects.

  • 16.
    Almingol, Oscar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Construction of a C-PV prototype2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The following Master Thesis will talk about a C-PV prototype using bifacial PV technology, based on the Solarus Collector. The Solarus Collector consists in two PV cells built on a metallic receiver, where there are some water channels flowing through it, allowing to cool down the PV cells, thus increasing their efficiency. The collector also presents a reflector to provide irradiance to the back part of the receiver, where the other PV cells are located. The new prototype will present bifacial PV cells but not a metallic receiver. This construction aims to reduce the price of the receiver, but will not have a system to cool down the solar cells. This Master Thesis will be developed in the Solarus facilities, in collaboration with the Solarus members.

    In order to grasp an idea of this prototype, two main procedures will be done. Regarding the bifacial technology, a bifacial PV module will be measured under different conditions, depending on which sides can be illuminated or shaded. On the other hand, a thermodynamic simulation will be carried out on different geometries of the reflector and receiver, in order to figure out the evolution of the temperatures on the new prototype. This simulation will be done with a finite element method, widely known in this applications.

    The results will show several problems concerning this prototype. Although the measurements of the bifacial PV module will result beneficial and informative, the problem with the temperature will tend to back down this prototype. The lack of some system to cool down the bifacial cells will imply that the receiver could reach unacceptable temperatures. This hypothesis will be drawn under some specific conditions, so they will not be completely devastating to the idea of using bifacial cells, but perhaps a different approach should be used in case it is desired to continue this work. 

  • 17.
    Almström, Erica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Att förstå evolution genom laboration2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Undersökningar visar att elever har svårt att ta till sig evolutionsteorin och i stället väljer att förklara evolutionen med icke vetenskapliga argument. Till exempel väljer de att förklara fjällharens vita vinterpäls med att en vit päls gör att den syns sämre. Det här är ett exempel på att eleverna gärna förklarar evolutionen som behovsstyrd. En laboration utformades för att illustrera hur variation och urval ger evolution i en plantpopulation. Laborationen går ut på att eleverna under en tid studerar en population med plantor som utsätts för torka. Plantorna har olika simulerade genotyper och kommer därför att reagera olika på torkstressen. Tanken med laborationen var att få elever att använda sig av mer vetenskapliga förklaringar till evolutionen istället för icke veteskapliga. Resultaten visar att eleverna ändrat uppfattning, men inte riktigt till en mer vetenskaplig förklaring utan de har gått från sin tidigare förklaringsmodell till att inte riktigt kunna förklara vad som händer vid evolution.

  • 18.
    Amaya, Jorge
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Pedalkraft system: Stödsystem för elproduktion i småskalighet2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is aimed at people who are interested in using the new environmentally friendlymethods of electricity generation or people who already use small wind turbines and solarpanels with the need for an additional energy source in small cabins or remote locations whereaccess to electricity networks is impossible. Aims of this work is first to build a system forgenerating electricity using a bicycle. Second is determining the amount of electrical energy aperson can generate with the system. Finally answer if this system could be used as a supportsystem for electricity generation in small scale.

    The first objective is to design a system using power control where the power generatedsupplied the loads. The mechanical part will be constructed as part of the energy source, thenwill be designed a control for controlling the power via electronic components, electrical loadssupplied by the system, will be simulated. To know the generated power to the control circuitwill install a meter and a serial communication device for communicating with a computer.

    It carries out a research on other systems and products in the Swedish market, to answer whetherthis system can be a backup system for electricity generation in small scale.

    The construction of a pedaling power system is achieved using a twelve volt direct currentmotor with permanent magnet as an energy source. System has the ability to show in an LCDdisplay and transmit through the serial ports, the value of the generated power. System canguide the power to the loads by using a microcontroller. Power generated by the system showedthat it is significant to be considered as an additional energy source, stand-alone or integratedwith other systems.

  • 19.
    Amin, A.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Teleconnect GmbH, Dresden, Germany; University of Applied Sciences Dresden, Dresden, Germany.
    Bluschke, A.
    Teleconnect GmbH, Dresden, Germany.
    Emery, S.
    Innodul AG, Zürich, Switzerland.
    Krüger, F.
    Teleconnect GmbH, Dresden, Germany; University of Applied Sciences Dresden, Dresden, Germany.
    Matthews, M.
    Teleconnect GmbH, Dresden, Germany.
    Rietzsch, P.
    Teleconnect GmbH, Dresden, Germany.
    Steglich, R.
    Contec Steuerungstechnik and Automation GmbH, Ebbs, Austria.
    Multi-carrier transmission over si-pof2011In: POF 2011: 20th International Conference on Plastic Optical Fibers - Conference Proceeding, 2011, 81-86 p.Conference paper (Refereed)
    Abstract [en]

    Multi-carrier modulation (MCM) is today’s method of choice for communication systems. This is also true for SI-POF. The basics of MCM and special characteristics for the optical transmission using SI-POF are explained within this paper. Current approaches for MCM over SI-POF are described: Teleconnect’s G.hn based solution for home networking and Innodul’s DMT-based Gigabit solution.

  • 20.
    AMIN, AHMED
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Implementation and Investigation of VDSL2 Signal Modulation/Demodulation Functions for FDM Solution via POF Channel2011Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    For higher data rate and attractive price level internet service Very High Data rate Subscriber Line 2 (VDSL2) is a perfect option. VDSL2 is a great achievement in Digital Subscriber Line (DSL) technology. It has a good impact in modern triple play (Voice, Data and Video) Internet service but for modern world applications required more data rate than the VDSL2 system can provide but it should be inexpensive and easy to install. So the desired goal of this thesis work is to achieve higher bitrates for VDSL2 system, by transmitting multiple VDSL2 signal using Plastic Optical Fiber (POF) channel instead of copper channel. POF channel is a suitable solution for high data rate application. Moreover POF is very rugged and suitable for high data rate application because of optical based transmission and it’s also very easy to implement into the interior networking. Moreover POF doesn’t have any impact of Electro Magnetic Interference because of optical transmission. So several VDSL2 signals are amplitude modulated to allocate specific frequency band and combined together which can be called as frequency division multiplexing and POF is used as channel to carry the combined signal which provide much higher bit rate than single signal and efficiently utilize the bandwidth of the channel. Then at the receiver end the combined signals are split and amplitude demodulate at the respective receiver to recover the expected frequency band for the receiver.       

  • 21.
    Amin, Shoaib
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. KTH Royal Institute of Technology, Stockholm, Sweden.
    Characterization and Linearization of Multi-band Multi-channel RF Power Amplifiers2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The World today is deeply transformed by the advancement in wireless technology. The envision of a smart society where interactions between physical and virtual dimensions of life are intertwined and where human interaction is mediated by machines, e.g., smart phones, demands increasingly more data traffic. This continual increase in data traffic requires re-designing of the wireless technologies for increased system capacity and flexibility. In this thesis, aspects related to behavioral modeling, characterization, and linearization of multi-channel/band power amplifiers (PAs) are discussed.

    When building a model of any system, it is advantageous to take into account the knowledge of the physics of the system and include into the model. This approach could help to improve the model performance. In this context, three novel behavioral models and DPD schemes for nonlinear MIMO transmitters are proposed.

    To model and compensate distortions in GaN based RF PAs in presence of long-term memory effects, novel models for SISO and concurrent dual-band PAs are proposed. These models are based on a fixed pole expansion technique and have infinite impulse response. They show substantial performance improvement. A behavioral model based on the physical knowledge of the concurrent dual-band PA is derived, and its performance is investigated both for behavioral modeling and compensation of nonlinear distortions.

    Two-tone characterization is a fingerprint method for the characterization of memory effects in dynamic nonlinear systems. In this context, two novel techniques are proposed. The first technique is a dual two-tone characterization technique to characterize the memory effects of self- and cross-modulation products in concurrent dual-band transmitter. The second technique is for the characterization and analysis of self- and cross-Volterra kernels of nonlinear 3x3 MIMO systems using three-tone signals.

  • 22.
    Amin, Shoaib
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Characterization and Linearization of Multi-channel RF Power Amplifiers2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The demands for high data rates and broadband wireless access requirethe development of wireless systems that can support wide and multi-bandsignals. To deploy these signals, new radio frequency (RF) front-ends are requiredwhich impose new challenges in terms of power consumption efficiencyand sources of distortion e.g., nonlinearity. These challenges are more pronouncedin power amplifiers (PAs) that degrade the overall performance ofthe RF transmitter.Since it is difficult to optimize the linearity and efficiency characteristicsof a PA simultaneously, a trade-off is needed. At high input power, a PAexhibits high efficiency at the expense of linearity. On the other hand, atlow input power, a PA is linear at the expense of the efficiency. To achievelinearity and efficiency at the same time, digital pre-distortion (DPD) is oftenused to compensate for the PA nonlinearity at high input power. In case ofmulti-channel PAs, input and output signals of different channels interactwith each other due to cross-talk. Therefore, these PAs exhibit differentnonlinear behavior than the single-input single-output (SISO) PAs. The DPDtechniques developed for SISO PAs do not result in adequate performancewhen used for multi-channel PAs. Hence, an accurate behavioral modeling isessential for the development of DPD for multi-channel RF PAs.In this thesis, we propose three novel behavioral models and DPD schemesfor nonlinear multiple-input multiple-output (MIMO) transmitters in presenceof cross-talk. A study of the source of cross-talk in MIMO transmittershave been investigated to derive simple and powerful modeling schemes.These models are extensions of a SISO generalized memory polynomial model.A comparative study with a previously published MIMO model is also presented.The effect of coherent and partially non-coherent signal generationon DPD performance is also highlighted. It is shown experimentally thatwith partially non-coherent signal generation, the performance of the DPDdegrades compared to coherent signal generation.In context of multi-channel RF transmitters, PA behavioral models andDPD schemes suffer from a large number of model parameters with the increasein nonlinear order and memory depth. This growth leads to highcomplexity model identification and implementation. We have designed aDPD scheme for MIMO PAs using a sparse estimation technique for reducingmodel complexity. This technique also increases the numerical stability whenlinear least square estimation model identification is used.A method to characterize the memory effects in a nonlinear concurrentdual-band PAs is also presented. Compared to the SISO PAs, concurrentdual-band PAs are not only affected by intermodulation distortions but alsoby cross-modulation distortions. The characterization of memory effects inconcurrent dual-band transmitter is performed by injecting a two-tone testsignal in each input channel of the transmitter. Asymmetric energy surfacesare introduced for the intermodulation and cross-modulation products, whichcan be used to identify the power and frequency regions where the memory effects are dominant.

  • 23.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Dept of Signal Processing, KTH Royal Institute of Technology, Stockholm, Sweden.
    Händel, Peter
    Dept of Signal Processing, KTH Royal Institute of Technology, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Characterization and modeling of RF amplifiers with multiple input signals2016Conference paper (Refereed)
    Abstract [en]

    A characterization technique for RF PAs excited with multiple signals is presented. The technique can be used for characterization of memory effects in IM/CM products. The extracted information can in return be of use for modifying behavioral models to better capture memory in IM/CM products.

  • 24.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Department of Signal Processing, School of Electrical Engineering, KTH.
    Händel, Peter
    Department of Signal Processing, School of Electrical Engineering, KTH.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Digital Predistortion of Single and Concurrent Dual Band Radio Frequency GaN Amplifiers with Strong Nonlinear Memory Effects2017In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 65, no 7, 2453-2464 p., 7855827Article in journal (Refereed)
    Abstract [en]

    Electrical anomalies due to trapping effects in Gallium Nitride (GaN) power amplifiers (PAs)give rise to long-term or strong memory effects. We propose novel models based on infinite impulse response (IIR) fixed pole expansion techniques for the behavioural modeling and digital pre-distortion of single-input-single-output (SISO) and concurrent dual-bandGaN PAs. Experimental results show that the proposed models outperform the corresponding finite impulse response (FIR) models by up to 17 dB for the same number of model parameters. For the linearization of a SISO GaN PA the proposed models give adjacent channel power ratios (ACPRs) that are 7 to 17 dBlower than the FIR models. For the concurrent dual-band case, the proposed models give ACPRs that are 9to 14 dB lower than the FIR models.

  • 25.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. ACCESS Linnaeus Centre, Department of Signal Processing, KTH Royal Institute of Technology, Stockholm.
    Khan, Zain Ahmed
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. ACCESS Linnaeus Centre, Department of Signal Processing, KTH Royal Institute of Technology, Stockholm.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Händel, Peter
    ACCESS Linnaeus Centre, Department of Signal Processing, KTH Royal Institute of Technology, Stockholm.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Concurrent dual-band power amplifier model modification using dual two-tone test2016In: 46th Europena Microwave Conference (EUMC) 2016, 2016, 186-189 p.Conference paper (Refereed)
    Abstract [en]

    A dual two-tone technique for the characterization of memory effects in concurrent dual-band transmitters is revisited to modify a 2D-DPD model for the linearization of concurrent dual-band transmitters. By taking into account the individual nonlinear memory effects of the self- and cross-kernels, a new2D modified digital pre-distortion (2D-MDPD) model is proposed,which not only supersedes the linearization performance but also reduces the computational complexity compared to the 2DDPDmodel in terms of a number of floating point operations(FLOPs). Experimental results show an improvement of 1.7 dBin normalized mean square error (NMSE) and a 58% reduction in the number of FLOPs.

  • 26.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. KTH.
    Landin, Per
    Chalmers University of Technology.
    Händel, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. ACCESS Linnaeus Centre, Signal Processing Lab, KTH Royal Institute of Technology.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Behavioral Modeling and Linearization of Crosstalk and Memory Effects in RF MIMO Transmitters2014In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 62, no 4, 810-823 p.Article in journal (Refereed)
    Abstract [en]

    This paper proposes three novel models for behavioral modeling and digital pre-distortion (DPD) of nonlinear 2$,times,$ 2 multiple-input multiple-output (MIMO) transmitters in the presence of crosstalk. The proposed models are extensions of the single-input single-output generalized memory polynomial model. Three types of crosstalk effects were studied and characterized as linear, nonlinear, and nonlinear & linear crosstalk. A comparative study was performed with previously published models for the linearization of crosstalk in a nonlinear 2 $,times,$2 MIMO transmitter. The experiments indicate that, depending on the type of crosstalk, the selection of the correct model in the transmitter is necessary for behavioral modeling and sufficient DPD performance. The effects of coherent and partially noncoherent signal generation on the performance of DPD were also studied. For crosstalk levels of ${-}{hbox{30}}$ dB, the difference in the normalized mean square error and adjacent channel power ratio was found to be 3–4 dB between coherent and partially noncoherent signal generation.

  • 27.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. KTH, Signalbehandling.
    Landin, Per N.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Händel, Peter
    KTH, Signalbehandling.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    2D Extended envelope memory polynomial model for concurrent dual-band RF transmitters2017In: International journal of microwave and wireless technologies, ISSN 1759-0795, E-ISSN 1759-0787Article in journal (Refereed)
    Abstract [en]

    The paper presents a 2D extended envelope memory polynomial (2D-EEMP) model for concurrent dual-band radio frequency (RF) power amplifiers (PAs). The model is derived based on the physical knowledge of a dual-band RF PA. The derived model contains cross-modulation terms not included in previously published models; these terms are found to be of importance for both behavioral modeling and digital pre-distortion (DPD). The performance of the derived model is evaluated both as the behavioral model and DPD, and the performance is compared with state-of-the-art2D-DPD and dual-band generalized memory polynomial (DB-GMP) models. Experimental result shows that the proposed model resulted in normalized mean square error (NMSE) of -51.7/-51.6dB and adjacent channel error power ratio (ACEPR) of -63.1/-63.4 dB, for channel 1/2, whereas the 2D-DPD resulted in the largest model error and DB-GMP resulted in model parameters that are 3 times more than those resulted with the proposed model with the same performance. As pre-distorter, the proposed model resulted in adjacent channel power ratio (ACPR) of -55.8/ -54.6 dB for channel 1/2 and is 7-10 dB lower than those resulted with the 2D-DPD model and2-4 dB lower compared to the DB-GMP model.

  • 28.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Mehmood, Imran
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    DETECTION OF MULTIPLE TARGETS USING ULTRA-WIDEBAND RADAR2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In recent years, ultra-wideband (UWB) radars are gaining popularity in the radar field mainly inindustrial and commercial areas. The UWB radar has the potential of dramatically improving thecontrol and surveillance of industrial processes in confined areas.The report provides an introduction to radar systems and detail working principle of M-sequenceUWB radar and methodology of how detection of targets is carried out. First two chapters of thereport describes the working of radar systems and M-sequence radar whereas in the later part ofthe report, different detection algorithms are discussed which has been implemented in thepresent radar simulations. In conventional radar the main detection algorithm is matched filteringwhere the transmitted signal is correlated with the received signal. Whereas UWB signal is nonsinusoidalthat is vulnerable to change in its shape during entire radar operation. This is thereason, the traditional signal processing methods like matched filtering or correlation process arenot advisable for UWB signals. Therefore, a different detection scheme known as Inter-periodcorrelation process (IPCP) has been studied.IPCP technique had been implemented and a comparison was made with the conventional targetdetection algorithm. On the basis of comparison made in this project, it has been observed thatthe conventional target detection methods are not effective in case of M-sequence UWB radar.The simulation results shows that by implementing IPCP method, performance close to 8-bitADC can be achievable with 1-bit comparator, also with IPCP implementation system resolutioncan be enhance effectively.Main focus was to analyze how close the system can detect two targets, therefore in all themeasurements i.e. practical and simulated measurements, only two targets were used.

  • 29.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. KTH, Signalbehandling.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    Department of Signal Processing, KTH Royal Institute of Technology, Stockholm, Sweden .
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Characterization of concurrent dual-band power amplifiers using a dual two-tone excitation signal2015In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 64, no 10, 2781-2791 p., 7104121Article in journal (Refereed)
    Abstract [en]

    A method to characterize the memory effects in a nonlinear concurrent dual-band transmitter is presented. It is an extension of the conventional two tone test for power amplifiers to concurrent dual band transmitters. The output signal of a concurrent dual-band transmitter is affected not only by intermodulation products but also by cross-modulation products. In one frequency band, the transmitter is excited by a two tone signal which frequency separation is swept. In the second band the transmitter is concurrently excited by an other two tone signal with slightly wider frequency separation. The frequency difference of the two signals is fixed during the frequency sweep. The two tone test is made at different power levels. The upper and lower third-order inter- and cross-modulation products are measured. The asymmetry between the upper and lower third-order inter- and cross-modulation products are measures of the transmitter's memory effects. The measurement results show that the memory effects are more dominant in the third-order intermodulation products than in the cross modulation products. An error analysis and system calibration was performed and measurement results for two different devices are presented.

  • 30.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Händel, Peter
    Department of Information Science and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Rebuttal to "On Dual-Band Amplifications Using Dual Two-Tones Clarifications and Discussions"2017In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 66, no 10, 2795-2797 p.Article in journal (Refereed)
    Abstract [en]

    This rebuttal is to "€œOn dual-band amplifications using dual two-tone: Clarifications and discussion". In the following, we provide our reply.

  • 31.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Zenteno, Efrain
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Landin, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    ACCESS Linnaeus Centre, Signal Processing Lab, KTH Royal Institute of Technology.
    Noise Impact on the Identification of DigitalPredistorter Parameters in the Indirect LearningArchitecture2012In: 2012 Swedish Communication Technologies Workshop (Swe-CTW), IEEE conference proceedings, 2012, 36-39 p.Conference paper (Refereed)
    Abstract [en]

    The indirect learning architecture (ILA) is the mostused methodology for the identification of Digital Pre-distorter(DPD) functions for nonlinear systems, particularly for highpower amplifiers. The ILA principle works in black box modelingrelying on the inversion of input and output signals of thenonlinear system, such that the inverse is estimated. This paperpresents the impact of disturbances, such as noise in the DPDidentification. Experiments were performed with a state-of-artDoherty power amplifier intended for base station operationin current telecommunication wireless networks. As expected,a degradation in the performance of the DPD (measured innormalized mean square error (NMSE)) is found in our experiments.However, adjacent channel power ratio (ACPR) canbe a misleading figure of merit showing improvement in theperformance for wrongly estimated DPD functions.

  • 32.
    Andersson, Daniel
    et al.
    Radarbolaget.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Ottoson, Patrik
    Radarbolaget.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Radar Images of Leaks in Building Elements2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 78, 1726-1731 p.Article in journal (Refereed)
    Abstract [en]

    Through leakage in the building envelope there is a penetration of air, water vapor and particles. The degree of leakage of air can be quantified by existing methods. However, the location of adventitious openings is often not known. In order to overcome the limitations in existing methods, a non-contact and non-destructive method based on ultra-wide bandwidth radar technology is suggested. A test-bed is designed that can measure with different polarization to be able to detect flaws in different directions. Initial measurements shows promising results for further development of the method of using radar images to find leaks in building elements.

  • 33.
    Andersson, Daniel
    et al.
    Radarbolaget, Gävle.
    Wallin, Kjell
    Radarbolaget, Gävle.
    Javashvili, Otar
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Beckman, Claes
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    M-Sequence UWB Radar for Industrial Applications2010In: Program of GigaHertz Symposium 2010, March 9-10, at Lund University, 2010Conference paper (Other academic)
    Abstract [en]

    Ultra Wideband Radar has the potential of dramatically improving the control and surveillance of industrial processes in confined areas. An example is the application of UWB radar for surveillance of furnaces for heath treatment of steel billets developed by Radarbolaget in Gävle.

    In our installation at AB Sandvik Materials Technology, we have shown that by using a non-destructive UWB Radar technique it is possible to visualize in real-time the ongoing process inside the furnace behind a 0.5 m thick ceramic wall. Since the operating temperature inside the furnace is 1200 °C, there is today no other known method capable of visualizing the process for the operator of the furnace. The system is therefore designed to sustain high temperatures and powerful electromagnetic disturbances while performing measurement with wide dynamics and high stability.

    The design of this radar is based on the idea of transmitting a continuous m-sequence and then detecting the correlated impulse response (see figure below). The wide bandwidth is a requirement for obtaining high spatial accuracy and resolution but puts further requirements on the design of the antennas and the electronics. Our results show that with this technique it is possible to determine the deformation of the steel billets inside the furnace with an accuracy of less than 5 mm. The radar system is also able to detect deformations in the furnace wall

    The m-sequence radar has many advantages over other UWB radar technologies since it e.g. does not require many analogue components. Its performance is a result of the choice of code length, sampling rate and averaging. However, the resolution is still limited by the impulse response of the analogue antenna (ringing).

    In this paper system parameters that affect the overall performance of an m-sequence radar are reviewed and means of enhancing its performance are discussed.

  • 34.
    Andersson, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    "It's funny that we don't see the similarities when that's what we're aiming for": Visualizing and challenging teachers' stereotypes of gender and science2012In: Research in science education, ISSN 0157-244X, E-ISSN 1573-1898, Vol. 42, no 2, 281-302 p.Article in journal (Refereed)
    Abstract [en]

    This study illuminates teachers’ conceptions of gender and science and possibilities to challenge these conceptions. Since 2005, a group of teachers (K-6) inSwedenhave met approximately once a month in two-hour seminars to discuss and develop their instruction in science and technology based on a gender perspective. The present data consist mainly of audio-recordings of the teacher seminars and video-recordings of science/technology activities with students. Analysis of the empirical data has been carried out in several stages and was inspired by thematic analysis, the theoretical framework of which is based on Hirdman’s and Beauvoir’s theories of gender. The results show that the teachers’ ideas about gender/equity and science exist on several levels, within which various conceptions are represented. On the one hand, “reasoning around similarity”, where teachers consider that both girls and boys should have the same prerequisites for working with science/technology. In contrast, stereotyped conceptions of girls and boys when the teachers evaluate their activities with students, where condescending attitudes toward girls are also observed. The girls’ ways of working with science/technology are not as highly valued as the boys’, and this outlook on children can ultimately have consequences for girls’ attitudes toward the subject. When teachers are allowed to read their own statements about the girls, they get “a glimpse of themselves”, and their condescending ideas about girls are made visible. In this way, the teachers can begin their active work toward change, which may lead to new outlooks on and attitudes toward students.

  • 35.
    Andersson, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Krönika: utbytta ord kan motverka fördomar2011In: Genus, ISSN 1403-8943, no 2, 25-25 p.Article in journal (Other (popular science, discussion, etc.))
  • 36.
    Andersson, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Lärare för förändring: att synliggöra och utmana föreställningar om naturvetenskap och genus2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main focus in this thesis is teachers’ gender awareness related to scientific practice. The thesis is based on two different empirical studies: a longitudinal action research study together with a group of teachers (K-6) and a study during an in-service development course where experienced teachers applied gender theory on a real classroom situation, a case. 

     

    The studies show that working with gender is complicated and comprises of many aspects of human life. An important part of gender awareness is to be able to relate to these aspects. A question of vital importance is to challenge conceptions of gender in such a way that the conceptions will be verbalized and thereby visualized. Moreover, the studies show that feminist pedagogy and theory of science can lead to a new approach to teaching and learning in science. For teachers without any background in science, there are other competences than just subject matter knowledge that are vital for teaching. Feminist perspectives in professional development reinforce teachers’ pedagogical competences and their pedagogical content knowledge and thereby make these teachers feel they participate in the scientific practice and contribute in developing both the stuff of knowledge and its culture.

     

    The thesis also contributes to new methodological knowledge about action research. One of the results is that time is an important factor to take into consideration depending on what kind of change you want to receive. The researcher engaged in action research as an "outsider" has an important function in order to monitor the process and pay attention and use critical events to drive the change process forward.        

     

  • 37.
    Andersson, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Vad har genus med naturvetenskap att göra?2013In: Den onaturliga naturen: Kunskapsmaterial om sexualitet och kön för lärare i naturkunskap och biologi på gymnasiet / [ed] Hans Olsson, Tommy Eriksson, RFSU , 2013Chapter in book (Other academic)
  • 38.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Danielsson, Anna
    Faculty of Education, University of Cambridge.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Acting for change: Challenging teachers through theatre, interventions and research2011Conference paper (Refereed)
  • 39.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Danielsson, Anna
    Institutionen för pedagogik, didaktik och utbildningsstudier, Uppsala universitet.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Chafing borderlands - pre-service teachers' meeting with different cultures in their education2012Conference paper (Refereed)
  • 40.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Centre for Gender Research, Uppsala University.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Centre for Gender Research, Uppsala University.
    What is science in preschool and what do teachers have to know to empower children?2014In: Cultural Studies of Science Education, ISSN 1871-1502, E-ISSN 1871-1510, Vol. 9, no 2, 275-296 p.Article in journal (Refereed)
    Abstract [en]

    In this article we problematize the purpose of teaching science in preschool and what competences preschool teachers need in order to conduct science activities in the classroom. The empirical data were collected through an action research project with five preschool and primary school teachers (K-6). In the first section we have used one situation, a floating-sinking experiment, as an illustration of how two different epistemological perspectives generate different foci on which kind of science teaching competences that are fruitful in preschool. In the first perspective, the central goal of science teaching is the development of the children’s conceptual understanding. With this perspective, we found that the science activities with the children were unsuccessful, because the children’s thoughts about concepts did not develop but even the situation enhanced a misconception concerning density. Moreover, the teacher was unsuccessful in supporting the children’s conceptual learning. The second perspective uses a feminist approach that scrutinizes science, where we investigate if the floating-sinking activity contributes to a feeling of participation in a scientific context for the children and if so how the teacher promotes this inclusion. This second perspective showed that the children’s scientific proficiency benefited from the situation; they had acquired a positive experience of the density concept that they could build upon which was reinforced by the teacher. The children discovered that they had power over their own learning by using an experimental approach. On the basis of these findings, we conclude that there are competences other than subject matter knowledge that are also important when preschool teachers engage children in scientific activities. Through process-oriented work with the teacher group, we identified four concrete skills: paying attention to and using children’s previous experiences; capturing unexpected things that happen at the moment they occur; asking questions that challenge the children and that stimulate further investigation; situated presence, that is, “remaining” in the situation and listening to the children and their explanations. We discuss possible ways to move preschool teachers away from their feelings of inadequacy and poor self-confidence in teaching science by reinforcing this kind of pedagogical content knowledge.

  • 41.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Scantlebury, Kathryn
    Department of Chemistry and Biochemistry, University of Delaware, USA.
    "We do science, we don't do gender!" Challenging science teaching education: Gender awareness in contructing knowledge of science and science teaching2015In: Feminist Pedagogy in Higher Education : Critical Theory and Practice / [ed] T. P. Light, J. Nicolas & R. Bondy, Waterloo, ON, Canada: Wilfrid Laurier University Press , 2015Chapter in book (Refereed)
  • 42.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Gustafsson, Christina
    University of Gävle, Faculty of Education and Business Studies, Department of Culture Studies, Religious Studies and Educational Sciences.
    Methodological dilemmas in action researchIn: Educational action research, ISSN 0965-0792, E-ISSN 1747-5074Article in journal (Refereed)
    Abstract [en]

    In this study we want to call attention to and discuss two aspects of importance for work toward change regarding fundamental values through action research. The first aspect is time, and taking it into account according to “the action research spiral”. The second aspect concerns the importance of critical events for making progress and challenging preconceived notions. We also stress that researchers as “outsiders” have the opportunity to overview the process in a way that the other participants (insiders) do not. The empirical data is collected from an action research project on science and gender conducted inSweden with teachers from preschool and K-6. The collaboration was proceeded during 2005 to 2010, a total of 57 months.   

  • 43.
    Andersson, Lina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Lärares tankar och idéer kring musik i idrottsundervisningen2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att undersöka hur och varför lärare i ämnet idrott och hälsa på gymnasiet använder sig utav musik som ett pedagogiskt verktyg samt varför de inte använder musik. Syftet är även att undersöka om gymnasielärarna i ämnet idrott och hälsa blir påverkade av några yttre faktorer som kan resultera i att de använder musiken i sin undervisning. Studien är baserad på kvalitativa intervjuer med åtta lärare i ämnet idrott och hälsa på gymnasiet. Resultatet visar att lärarnas tankar och idéer kring användandet av musik samt hur de upplever att eleverna agerar till musik stämmer bra överens med tidigare forskning som visar många fördelar med att arbeta till musik. Resultatet visar även att de yttre faktorer som påverkar lärarna mest, när det gäller hur det använder sig utav musik i deras undervisning, är eleverna och deras musikintresse. Slutsatsen av studien är att lärarna upplever att musik motiverar och inspirerar elever till rörelseglädje samt en högre prestationsnivå. Hur de använder musiken är antingen som bakgrundmusik eller som ett hjälpmedel.

  • 44.
    Andersson, Lorraine
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Pedagogisk verksamhet i botanisk trädgård- mer än växtkunskap2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I dag då allt fler människor bor i städer blir konsekvensen att kontakten med naturmiljöer minskar. Botaniska trädgårdar är då en betydelsefull plats för rekreation och välbefinnande i urban miljö. Allt sedan de första moderna botaniska trädgårdarna i mitten av 1500-talet anlades har undervisning varit en viktig del av trädgårdarnas verksamhet.

    Syftet med studien har varit att undersöka några botaniska trädgårdars pedagogiska verksamhet. Fokus har lagts på att ta reda på hur trädgårdarna arbetar med pedagogiska/sociala projekt. En central utgångspunkt i botaniska trädgårdarnas pedagogiska och sociala verksamhet är människans beroende av växter. För att inse växterna/naturens betydelse för människors vardagliga liv har det visat sig att tillämpad botanik är den metod som allmänheten har haft lättast att ta till sig.

    Tre svenska och tre utländska botaniska trädgårdar valdes ut för att ingå i studien. Metoden jag använt mig av är litteraturstudier kombinerat med kvalitativa intervjuer. Framgångsfaktorer avseende den pedagogiska verksamheten, som sker i de botaniska trädgårdarna, är bland annat samarbete med andra organisationer samt möjligheten till delaktighet i närområdets aktiviteter. Odlings- och trädgårdsprojekten genererar positiva effekter både för individen och lokalsamhället. Under studiens gång har mer och mer framkommit, att botaniska trädgårdar är en viktig resurs vad gäller att driva och utveckla en pedagogisk/social verksamhet.

     

  • 45.
    Andersson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Bergviksäpplet och dess fruktsättning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Trees of Bergvik apple (Bergviksäpple) planted between 2001 and 2007 have shown varying harvest. This study investigates why some trees gets low or no harvest while others get significantly higher harvest. The aim is to identify some reasons why fruiting differs between the trees and if possible suggest and/or enlighten the tree owners what can be done to improve fruiting. The study includes 25 trees, mostly located in Hälsingland, Sweden. The tree owners have answered two questionnaires, first in the spring with questions regarding flowering and the second in the autumn, regarding harvest. The answers to these questionnaires form the foundation for this work.

    The result of the study reveals differences in harvest. Older trees and/or trees with good vegetative growth have larger harvest while trees with poor growth in some cases didn’t even get flowers. Younger trees with good growth gave good harvest. This concludes that the single most important factor to get good harvest is good vegetative growth.

  • 46.
    Andersson, Maria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Bland mossa och småkryp -att stimulera barns intresse förnaturen med hjälp av uppdragskort2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 47.
    Andersson, Sara
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Måste vi räkna?: En (enkel) matematisk början för barn och pedagoger2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta examensarbete var att skapa ett matematiskt arbetsmaterial för pedagoger. Materialet ska underlätta för pedagoger som känner sig obekväma eller illa till mods vid tanken på att arbeta med matematik. Materialet, som består av handledning, arbetsmaterial och ett formulär togs fram efter att ha studerat litteratur och efter att förtester med fyra barn gjorts. Materialet är tänkt att hjälpa pedagoger att få syn på de fem grundläggande principerna hos barn som behövs för att bli bra på aritmetik. De fem principerna är ramsräkning, sifferkunskap, antalsräkning, ordinaltalsräkning och spontan antalsuppfattning. Materialet testades av tre pedagoger. Deras svar analyserades och bedömdes efter i förväg utvalda kriterier. Några kriterier uppfylldes medan andra kräver en omarbetning av materialet för att uppfyllas. Till sist togs nya kriterier fram för att kunna förbättra produkten i ett nästa skede. Examensarbetet visar att det inte behöver vara krångligt och svårt att arbeta med matematik i förskolan även om matematik kan upplevas som krångliga ekvationer, väcka obehags känslor eller upplevs kräva mycket förberdelser.

  • 48.
    Andersson, Tony
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Habitatval hos yngel av öring (Salmo trutta) i en undersökning i Nedre Dalälven2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project was to examine important parameters for juvenile brown trout habitat selection in their first months after hatching. The study was carried out after approximately 30 000 fry had been released by the County Administrative Board of Gävleborg. Data on habitat selection was collected from five different localities at the river Dalälven, near Gysinge, Sweden. The method of estimating preferred habitat was to determine remaining fry after a period of seven weeks by electrofishing.

    This study confirms that the optimal local habitat choice for juvenile trout is where the substrate size 60- 200 mm is present and a hypothesis is proposed that this substrate is of importance for juvenile trout survival as it gives shelter in the presence of predators. Based on previous research the study gives some suggestions to which important habitat characteristics that were missing where no trout were recaptured.

  • 49.
    Angermann, Lutz
    et al.
    Clausthal University of Technology, Clausthal, Germany..
    Shestopalov, Yury V.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Mathematics.
    Yatsyk, Vasyl
    O. Ya, Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine.
    Mathematical models for scattering and generation of plane wave packets on layered cubically polarisable structures2013In: Far East Journal of Applied Mathematics, ISSN 0972-0960, Vol. 81, no 1-2, 1-31 p.Article in journal (Refereed)
    Abstract [en]

    The paper deals with different formulations of mathematical models for the analysis of processes of resonance scattering and generation of plane wave packets on isotropic, nonmagnetic, linearly polarised media with a nonlinear, layered dielectric structure of cubic polarisability. For each formulation, sufficient conditions for the existence and, partially, uniqueness of the corresponding solution are derived.

  • 50.
    Angermann, Lutz
    et al.
    Technische Universität Clausthal, Institut für Mathematik, Clausthal-Zellerfeld, Germany .
    Shestopalov, Yury V.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Mathematics.
    Yatsyk, Vasyl V.
    O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine .
    Eigenmodes of linearised problems of scattering and generation of oscillations on cubically polarisable layers2015In: Inverse Problems and Applications / [ed] Larisa Beilina, Springer-Verlag New York, 2015, Vol. 120, 67-80 p.Conference paper (Refereed)
    Abstract [en]

    In the frequency domain, the resonant properties of nonlinear structures are determined by the proximity of the scattering/generation frequencies of the nonlinear structures to the complex eigenfrequencies of the corresponding homogeneous linear spectral problems with the induced nonlinear permeability of the medium. Here the case of cubically polarisable, canalising, and decanalising layers is considered.

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