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  • 1.
    A Atlasov, Kirill
    et al.
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Felici, Marco
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Karlsson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gallo, Pascal
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Rudra, Alok
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Dwir, Benjamin
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    Kapon, Eli
    Ecole Polytech Fed Lausanne, Lab Phys Nanostruct, CH-1015 Lausanne, Switzerland .
    1D photonic band formation and photon localization in finite-size photonic-crystal waveguides2010Inngår i: OPTICS EXPRESS, ISSN 1094-4087, Vol. 18, nr 1, s. 117-122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A transition from discrete optical modes to 1D photonic bands is experimentally observed and numerically studied in planar photonic-crystal (PhC) L-N microcavities of length N. For increasing N the confined modes progressively acquire a well-defined momentum, eventually reconstructing the band dispersion of the corresponding waveguide. Furthermore, photon localization due to disorder is observed experimentally in the membrane PhCs using spatially resolved photoluminescence spectroscopy. Implications on single-photon sources and transfer lines based on quasi-1D PhC structures are discussed.

  • 2.
    A Herrera, I
    et al.
    Norwegian University Science and Technology NTNU.
    Woltjer, Rogier
    Linköpings universitet, Institutionen för datavetenskap, CSELAB - Cognitive Systems Engineering Laboratory. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Interaktiva och kognitiva system.
    Comparing a multi-linear (STEP) and systemic (FRAM) method for accident analysis2010Inngår i: RELIABILITY ENGINEERING and SYSTEM SAFETY, ISSN 0951-8320, Vol. 95, nr 12, s. 1269-1275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accident models and analysis methods affect what accident investigators look for, which contributory factors are found, and which recommendations are issued. This paper contrasts the Sequentially Timed Events Plotting (STEP) method and the Functional Resonance Analysis Method (FRAM) for accident analysis and modelling. The main issue addressed in this paper is the comparison of the established multi-linear method STEP with the new systemic method FRAM and which new insights the latter provides for accident analysis in comparison to the former established multi-linear method. Since STEP and FRAM are based on a different understandings of the nature of accidents, the comparison of the methods focuses on what we can learn from both methods, how, when, and why to apply them. The main finding is that STEP helps to illustrate what happened, involving which actors at what time, whereas FRAM illustrates the dynamic interactions within socio-technical systems and lets the analyst understand the how and why by describing non-linear dependencies, performance conditions, variability, and their resonance across functions.

  • 3.
    A. Sani, Negar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik.
    M-PSK and M-QAM Modulation/Demodulation of UWB Signal Using Six-Port Correlator2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays high speed and high data rate communication are highly demanded. Consequently, wideband and high frequency transmitter and receivers should be designed. New transmitters and receivers should also have low power consumption, simple design and low manufacturing price in order to fulfill manufacturers’ requests for mass production. Having all above specifications, six-port correlator is a proper choice to be used as modulator and demodulator in transmitters and receivers.

    In this thesis the six-port correlator is introduced, modeled and simulated using Advanced Design System (ADS) software. A simple six-port transmitter/receiver system with a line of sight link is modeled and analyzed in BER, path length and noise terms. The modulation in this system is QAM, frequency is 7.5 GHz and symbol rate is 500 Msymbol/s.

    Furthermore two methods are proposed for high frequency and high symbol rate M-PSK and M-QAM modulation using six-port correlator. The 7.5 GHz modulators are modeled and simulated in ADS. Data streams generated by pseudo random bit generator with 1 GHz bandwidth are applied to modulators. Common source field effect transistors (FETs) with zero bias are used as controllable impedance termination to apply baseband data to modulator. Both modulators show good performance in M-PSK and M-QAM modulation.

    Fulltekst (pdf)
    FULLTEXT01
  • 4.
    Aaboen, Lise
    NTNU, Trondheim.
    BATON-CHANGING ON EGGSHELLS – TRANSFERRING SUPPLIER RELATIONSHIPS WHEN MOVING PRODUCTION2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Production transfers are a result of outsourcing and offshoring decisions. Though, because of

    the strategic focus of the outsourcing literature have not the operational issues of how

    relationship development between sender, receiver and raw material been fully depicted. The

    purpose of the present paper is to explore relationship development connected to transfer of

    raw material supplies responsibility during transfer of production. To fulfil the purpose, four

    different production transfers were studied: three from Sweden to China, Romania and

    Hungary respectively and one transfer from Holland to Sweden. We can see that the

    dependence and power shifts gradually between the sender and the receiver and the

    relationship between them sets the arena for what relationship is developed between the

    receiver and the raw material suppliers. Furthermore, short social distances can over bridge

    cultural and technological distances to some extent, because it motivates to take the

    relationship into a more developed state.

  • 5.
    Aaboen, Lise
    et al.
    Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Fredriksson, Anna
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    The relationship development aspect of production transfer2016Inngår i: Journal of Purchasing and Supply Management, ISSN 1478-4092, E-ISSN 1873-6505, Vol. 22, nr 1, s. 53-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Production transfers are a result of outsourcing and offshoring decisions. Because of the strategic focus of the outsourcing literature, the operational issues of relationship development between sender and receiver and its impact on the transfer progress have not been fully depicted. The purpose of the present paper is to explore relationship development during production transfer. To fulfil this purpose, we studied three different production transfers and derived four propositions for further testing. Our main conclusions included that dependence and power gradually shift between the sender and the receiver and that the relationship between them sets the arena for what types of relationships can be developed between the receiver and the suppliers. Furthermore, short social distances can bridge cultural and technological distances to some extent, because it motivates the actors to bring their relationship into a more developed state. Finally, we noticed that the headquarters’ involvement can work both as an inhibitor as well as a converter.

    Fulltekst (pdf)
    fulltext
  • 6.
    Aalberg, L
    et al.
    National Bureau of Investigation, Finland.
    Andersson, K
    Swedish National Laboratory of Forensic Science.
    Bertler, C
    Swedish National Laboratory of Forensic Science.
    Cole, MD
    University of Strathclyde, Glasgow.
    Finnon, Y
    University of Strathclyde, Glasgow.
    Huizer, H
    Netherlands Forensic Institute.
    Jalava, K
    National Bureau of Investigation, Finland.
    Kaa, E
    Aarhus Universitet.
    Lock, E
    Université de Lausanne.
    Lopes, A
    Laboratorio Policia Cientifica, Lisbon, Portugal.
    Poortman-van der Maar, A
    Netherlands Forensic Institute.
    Sippola, E
    National Bureau of Investigation, Finland.
    Dahlén, Johan
    Swedish National Laboratory of Forensic Science.
    Development of a harmonised method for the profiling of amphetamines: II. Stability of impurities in organic solvents2005Inngår i: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 149, nr 03-Feb, s. 231-241Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study focused on the stability of 22 amphetamine impurities dissolved in six organic solvents: isooctane, toluene, ethanol, dichloromethane, ethyl acetate, and diethyl ether. The aim was to find the most inert, and thereby most suitable, solvent for amphetamine profiling. Mixtures of the impurities were prepared in the different solvents, and changes in the concentrations of the individual compounds over-time were monitored by gas chromatographic analysis after 0, 4, 12, 24, 48, and 96 h. Isooctane and toluene provided the most inert conditions, although, a few of the impurities were insufficiently stable in these two solvents. The present experiments were performed as a part of the development of a harmonised method for profiling of amphetamine. The results can be used to support the choice of organic solvents for sample preparation. They also provide information about the stability of the impurities that are found in profiles of illicit amphetamine. This is essential due to the fact, that unstable compounds can have a negative influence on the comparison of profiles.

  • 7.
    Aaltio, Iiris
    et al.
    School of Economics and Business University of Jyväskylä, Finland.
    Kyrö, PaulaHelsinki School of Economics, Finland.Sundin, ElisabethLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Företagsekonomi. Linköpings universitet, Filosofiska fakulteten.
    Women, Entrepreneurship and Social Capital: A Dialogue and Construction2008Collection/Antologi (Annet vitenskapelig)
    Abstract [en]

    This book explores social capital as the multiple relationships between gender, management and entrepreneurship. Human resources are the social capital of a firm and business life, based on trust as well as on expertise, values and cultural diversity. This calls for cross-cultural knowledge and an understanding of gender issues and individual differences in the social capital of the firm and society. The dialogue between women entrepreneurship and social capital theory and research has its special place among other women entrepreneurship books, the number of which has lately increased. It strengthens still in some respect the fragmented voice of women entrepreneurship research by providing a landscape of women entrepreneurs as creators of, and created by, social capital. It indicates how women entrepreneurs appear to have a special position in forming, developing and reorganizing the social capital in the business world. In its eleven chapters, twenty-six researchers representing a variety of disciplines from different parts of the world are presenting findings on diverse aspects of the dialogue between women entrepreneurship and social capital. As a consequence the central concepts, social capital, entrepreneurship and gender, are given a variety of meanings. Women entrepreneurs and business owners regardless of their cultural context, branch and education provide interesting ideas to the global debate on equality and social capital.

  • 8.
    Aamir, Syed Ahmed
    Linköpings universitet. Linköpings universitet, Institutionen för systemteknik.
    A 65nm, Low Voltage, Fully Differential, SC Programmable Gain Amplifier for Video AFE2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Due to rapid growth of home entertainment consumer market, video technology has been continuously pushed to deliver sharper pictures with higher resolution. This has brought about stringent requirements on the video analog front end, which often coupled with the low power and low voltage regulations had to deal with short channel effects of the deep submicron CMOS processes.

    This thesis presents the design of a fully differential programmable gain amplifier, as a subcircuit of a larger video digitizing IC designed at division of Electronic Systems. The switched capacitor architecture of the PGA does not only buffer the signal, but performs compensation for the sync-tip of analog video signal.

    The pseudo differential OTA eliminates tail current source and maintains high signal swing and has efficient common mode feedforward mechanism. When coupled with a similar stage provides inherent common moode feedback without using an additional SC-CMFB block.

    The PGA has been implemented using a 65 nm digital CMOS process. Expected difficulties in a 1.2 V OTA design make themselves evident in 65 nm, which is why cascaded OTA structures were inevitable for attaining gain specification of 60 dB. Nested Miller compensation with a pole shifting source follower, stabilizes the multipole system. The final circuit attains up to 200 MHz bandwidth and maintains high output swing of 0.85 V. High slew rate and good common mode and power supply rejection are observed. Noise requirements require careful design of input differential stage. Although output source follower stabilized the system, it reduces significant bandwidth and adds to second order non-linearity.

    Fulltekst (pdf)
    FULLTEXT01
  • 9.
    Aamir, Syed Ahmed
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, J Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A 1.2-V pseudo-differential OTA with common-mode feedforward in 65-nm CMOS2010Inngår i: Proceedings of the 17th IEEE International Conference on Electronics, Circuits, and Systems, Institute of Electrical and Electronics Engineers (IEEE), 2010, s. 29-32Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, we describe the implementation of a 1. 2-V pseudo-differential operational transconductance amplifier (OTA) with common-mode feedforward (CMFF) and inher­ent common-mode feedback (CMFB) in a 65-nm, digital CMOS process. The OTA architecture provides an inher­ent CMFB when cascaded OTA structures are utilized andthis work has studied a cascaded amplifier consisting of fourstages. Due to the low-gain using core 65-nm circuit de­vices, the overall gain must be distributed on all four stages to acquire a gain of more than 60 dB, while maintaining a-3-dB bandwidth of 200 MHz. To achieve high gain, we propose using a modified, positive-feedback, cross-coupled input differential stage. The modified OTA achieves a high output swing of ± 0.85 V due to only two stacked transistors, 88 dB DC gain and a third-order harmonic of -60 dB for 800 mVpp at 30 MHz. Further on, in a capacitive buffer configuration, we achieve a high slew rate of 1240 V/µS, -3-dB bandwidth of 509 MHz, signal-to-noise ratio of 63 dB while consuming 10.4 mW power.

  • 10.
    Aamir, Syed Ahmed
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, J Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A 500-MHz low-voltage programmable gain amplifier for HD video in 65-nm CMOS2010Inngår i: Proceedings of 28th IEEE Norchip Conference., NORCHIP'10, Tampere: www.ieee.org , 2010, s. 1-4Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work describes the implementation of a 1.2-V programmable gain amplifier (PGA) for high-definition (HD) video digitizers in a 65-nm digital CMOS process. The “pseudo” switched-capacitor (SC) PGA architecture buffers the video signal, without switching, during the active video. The SC circuitry is used for setup of DC operating point during horizontal and vertical blanking periods. Additionally, it compensates for the `sync-tip' of analog video signals to an equal blanking level for increased dynamic range to the digitizer following the PGA. The operational transconductance amplifier (OTA) employed as main amplifier in the PGA is a pseudo-differential, positive-feedback input stage architecture with a common-mode feedforward (CMFF) technique. The common-mode feedback (CMFB) is provided once two OTAs are cascaded. Schematic-level simulation results show that the OTA maintains a -3-dB bandwidth of 550 MHz, while keeping the distortion HD3 at -60 dB for a 30-MHz, 850 mVpp high definition video signal. The 88 dB DC gain is distributed among four OTA stages and the overall, combined PGA achieves a signal-to-noise ratio of 63 dB. Due to only two stacked transistors, it achieves high output swing of ±0.85 V, 1240 V/μs slew rate while consuming 10.4 mW power.

  • 11.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ward, D A
    University of South Australia.
    Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains2011Inngår i: JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS, ISSN 0377-0427, Vol. 235, nr 5, s. 1342-1353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a recent paper by the current authors a new methodology called the Extended-Domain-Eigenfunction-Method (EDEM) was proposed for solving elliptic boundary value problems on annular-like domains. In this paper we present and investigate one possible numerical algorithm to implement the EDEM. This algorithm is used to solve modified Helmholtz BVPs on annular-like domains. Two examples of annular-like domains are studied. The results and performance are compared with those of the well-known boundary element method (BEM). The high accuracy of the EDEM solutions and the superior efficiency of the EDEM over the BEM, make EDEM an excellent alternate candidate to use in the animation industry, where speed is a predominant requirement, and by the scientific community where accuracy is the paramount objective.

  • 12.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ward, D A
    University of South Australia.
    The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains2010Inngår i: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, ISSN 1751-8113, Vol. 43, nr 18, s. 185202-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.

  • 13.
    Aarnio, Harri
    et al.
    Abo Akad University.
    Sehati, Parisa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi.
    Braun, Slawomir
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Nyman, Mathias
    Abo Akad University.
    de Jong, Michel P
    University of Twente.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Osterbacka, Ronald
    Abo Akad University.
    Spontaneous Charge Transfer and Dipole Formation at the Interface Between P3HT and PCBM2011Inngår i: Advanced Energy Materials, ISSN 1614-6832, E-ISSN 1614-6840, Vol. 1, nr 5, s. 792-797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the pursuit of developing new materials for more efficient bulk-heterojunction solar cells, the blend poly (3-hexylthiophene):[ 6,6]-phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) serves as an important model system. The success of the P3HT: PCBM blend comes from efficient charge generation and transport with low recombination. There is not, however, a good microscopic picture of what causes these, hindering the development of new material systems. In this report UV photoelectron spectroscopy measurements on both regiorandom-(rra) and regioregular-(rr) P3HT are presented, and the results are interpreted using the Integer Charge Transfer model. The results suggest that spontaneous charge transfer from P3HT to PCBM occurs after heat treatment of P3HT: PCBM blends. The resulting formation of an interfacial dipole creates an extra barrier at the interface explaining the reduced (non-)geminate recombination with increased charge generation in heat treated rr-P3HT: PCBM blends. Extensive photoinduced absorption measurements using both above-and below-bandgap excitation light are presented, in good agreement with the suggested dipole formation.

  • 14.
    Aaro, Gustav
    Linköpings universitet, Institutionen för datavetenskap.
    Smartphone Based Indoor Positioning Using Wi-Fi Round Trip Time and IMU Sensors2020Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    While GPS long has been an industry standard for localization of an entity or person anywhere in the world, it loses much of its accuracy and value when used indoors. To enable services such as indoor navigation, other methods must be used. A new standard of the Wi-Fi protocol, IEEE 802.11mc (Wi-Fi RTT), enables distance estimation between the transmitter and the receiver based on the Round-Trip Time (RTT) delay of the signal. Using these distance estimations and the known locations of the transmitting Access Points (APs), an estimation of the receiver’s location can be determined. In this thesis, a smartphone Wi-Fi RTT based Indoor Positioning System (IPS) is presented using an Unscented Kalman Filter (UKF). The UKF using only RTT based distance estimations as input, is established as a baseline implementation. Two extensions are then presented to improve the positioning performance; 1) a dead reckoning algorithm using smartphone sensors part of the Inertial Measurement Unit (IMU) as an additional input to the UKF, and 2) a method to detect and adjust distance measurements that have been made in Non-Line-of-Sight (NLoS) conditions. The implemented IPS is evaluated in an office environment in both favorable situations (plenty of Line-of-Sight conditions) and sub-optimal situations (dominant NLoS conditions). Using both extensions, meter level accuracy is achieved in both cases as well as a 90th percentile error of less than 2 meters.

    Fulltekst (pdf)
    fulltext
  • 15.
    Aasa, Amanda
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System.
    Svennblad, Amanda
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System.
    Design of an Automated Test Setup for Power-Controlled Nerve Stimulator Using NFC for Implantable Sensors2021Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Electrical stimulation on nerves is a relatively new area of research and has been proved to speed up recoveryfrom nerve damage. In this work, the efficiency and stability of antennas integrated on printed circuit boards provided by the department of electrical engineering are examined. An automated test bench containing a stepmotor with a slider and an Arduino is created. Different setups were used when measuring on the boards, which resulted in that the largest antenna gave the most stable output despite the distance between transmitterand receiver. The conclusion was that the second best antenna and the smallest one would be suitable as well,and the better choice if it is to be implemented under the skin. A physical setup consisting of LEDs, an Arduino, a computer, and a function generator was created to examinethe voltage control functionality, where colored LEDs were lit depending on the voltage level. The functionality was then implemented in a circuit that in the future shall be integrated on the printed circuit board. To control high voltages a limiter circuit was examined and implemented. The circuit was simulated and tested, with a realization that a feature covering voltage enlargement is needed for the future. 

    Fulltekst (pdf)
    fulltext
  • 16.
    Aasmundtveit, K.E.
    et al.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Samuelsen, E.J.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Guldstein, M.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Steinsland, C.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Flornes, O.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Fagermo, C.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Seeberg, T.M.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., N-7491 Trondheim, Norway.
    Pettersson, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Feidenhans'l, R.
    Forskningscenter Risø, DK-4000 Roskilde, Denmark.
    Ferrer, S.
    Europ. Synchrt. Radiation Facility, BP 220, F-38043 Grenoble Cedex, France.
    Structural anisotropy of poly(alkylthiophene) films2000Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 33, nr 8, s. 3120-3127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structural anisotropy of various poly(alkylthiophene) films have been studied by X-ray diffraction, using both conventional methods and synchrotron radiation at grazing incidence. Solution-cast films orient with the side chains preferably normal to the film surface, whereas spin-cast films of nonstereoregular material orient with both the main and the side chains in the film plane. For thick (10-50 µm) solution-cast films, the degree of orientation depends strongly on the solvent used for casting, and on the stereoregularity of the polymer, films of stereoregular materials being more oriented than those of nonregular materials. The most oriented nonregular films are those cast from mixtures of chloroform and tetrahydrofuran. Thin (50-500 nm) solution-cast films are more oriented than the thicker ones, and the effects of different stereoregularity or different casting solvents are small. For spin-cast films, the degree of orientation is independent of substrate and solvent. Spin-cast films of stereoregular material have two different phases: One with the side chains normal to the substrate, and another where they are parallel to the substrate. The diffraction peaks of spin-cast poly(octylthiophene) narrow considerably upon heating.

  • 17.
    Aasmundtveit, K.E.
    et al.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., Trondheim, Norway.
    Samuelsen, E.J.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskapelige U., Trondheim, Norway.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Pettersson, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Johansson, Tomas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Ferrer, S.
    Europ. Synchrt. Radiat. Facil. (E., F-38043, Grenoble, France.
    Structural aspects of electrochemical doping and dedoping of poly(3,4-ethylenedioxythiophene)2000Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 113, nr 1, s. 93-97Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical dedoping and redoping of p-toluene sulfonate doped poly(3,4-ethylenedioxythiophene) (PEDOT) has been studied with in situ grazing incidence diffraction with water used as an electrolyte. The diffraction peak positions and integrated intensities do not change significantly during doping and dedoping, while the peak widths increase upon dedoping and decrease upon doping. This implies that the lattice parameters and the relative positions of the polymer chains and the p-toluene sulfonate ions remain unchanged, the redox processes being carried out by the motion of smaller ions between the polymer and the electrolyte, and that the structural order decreases upon dedoping and increases upon doping in a reversible manner.

  • 18.
    Aasmundtveit, K.E.
    et al.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskaplige U., N-7491 Trondheim, Norway.
    Samuelsen, E.J.
    Institutt for Fysikk, Norges Tekn.-Naturvitenskaplige U., N-7491 Trondheim, Norway.
    Mammo, W.
    Institutionen för Organisk Kemi, Chalmers Tekniska Hôgskola, S-412 96 Göteborg, Sweden.
    Svensson, M.
    Institutionen för Organisk Kemi, Chalmers Tekniska Hôgskola, S-412 96 Göteborg, Sweden.
    Andersson, M.R.
    Institutionen för Polymerteknik, Chalmers Tekniska Hôgskola, S-412 96 Göteborg, Sweden.
    Pettersson, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Structural ordering in phenyl-substituted polythiophenes2000Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 33, nr 15, s. 5481-5489Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Various substituted poly(phenylthiophene)s have been studied by X-ray diffraction. They are semicrystalline, with very different degrees of crystallinity. Those with para-substituted phenyl groups have a low degree of crystallinity, whereas those with ortho-substituted phenyl groups are more crystalline. The most crystalline materials in this study have two equally long substituents on the phenyl ring, one at the ortho position and the other at the ortho or meta position on the opposite side of the phenyl ring. Poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) was most thoroughly studied, and a structural model is proposed. The structure of PDOPT is quite different from previously studied substituted polythiophenes in that the octyl side chains are directed normal to the thiophene planes. In this way, the conjugated polymer chains are kept separated from each other. Solution-cast and spin-cast PDOPT films are anisotropic, with the octyl side chains oriented normal to the film surface in both cases. This is contrary to the situation for poly(3-alkylthiophene)s, where solution-cast and spin-cast films orient in different ways.

  • 19. Aavikko, R
    et al.
    Saarinen, K
    Magnusson, Björn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Observation of vacancy clusters in HTCVD grown SiC2005Inngår i: Materials Science Forum, Vols. 483-485, 2005, Vol. 483, s. 469-472Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Positron lifetime spectroscopy was used to study defects in semi-insulating (SI) silicon carbide (SiC) substrates grown by high-temperature chemical vapor deposition (HTCVD). The measured positron lifetime spectra can be decomposed into two components, of which the longer corresponds to vacancy clusters. We have carried out atomic superposition calculations to estimate the size of these clusters.

  • 20.
    Aazh, H
    et al.
    Ealing General Hospital.
    Moore, B
    Cambridge University.
    Peyvandi, AA
    Ealing General Hospital.
    Stenfelt, Stefan
    Chalmers University of Technology.
    Influence of ear canal occlusion and static pressure difference on bone conduction thresholds: Implications for mechanisms of bone conduction2005Inngår i: International Journal of Audiology, ISSN 1499-2027, E-ISSN 1708-8186, Vol. 44, nr 5, s. 302-306Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of air pressure change on bone conduction (BC) hearing thresholds in the occluded ear was investigated. The pump manometer system of an impedance bridge was used to change the air pressure in the ear canal of twenty-two normally hearing subjects. BC thresholds were measured with: (1) open ear; (2) the ear canal occluded with a probe tube and application of 0 daPa air pressure; and (3) the ear canal occluded with a probe tube and application of -350 daPa air pressure. Thresholds were lower in condition 2 than in condition 1, the difference decreasing from 27 dB at 2500 Hz to 4.5 dB at 2000 Hz. Thresholds were higher in condition 3 than in condition 2. The results are interpreted in terms of changes in the relative contribution of the three routes of transmission for BC sound produced by occlusion and by a static pressure difference.

  • 21.
    Abadei, S.
    et al.
    Department of Microelectronics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Gevorgian, S.
    Department of Microelectronics, Chalmers University of Technology, 412 96 Göteborg, Sweden, Core Unit Research Center, Ericsson Microwave Systems, SE-431 84, Mölnda, Sweden.
    Kugler, Veronika Mozhdeh
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Helmersson, Ulf
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik.
    Andreasson, J.
    Department of Materials and Manufacturing Engineering, Luleå University of Technology, 971 87, Luleå, Sweden.
    Microwave properties of tunable capacitors basee on magnetron sputtered ferroelectric Na0.5K0.5NbO3 film on low and high resistivity silicon substrates2001Inngår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 39, nr 1-4, s. 359-366Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this work, small signal DC voltage dependent dielectric permittivity, loss tangent, and tuneability of magnetron sputtered epitaxial Na0.5K0.5NO3 films are studied experimentally. (100)-oriented Na0.5K0.5NbO3 films are deposited onto SiO2-buffered CMOS grade low resistivity (p = 10-20 cm) and high resistivity (p = 15-45 kcm) silicon substrates. Planar capacitors with 2 or 4 m gaps between electrodes have been fabricated on top of ferroelectric films. These devices have been characterized in the frequency range 1.0 MHz to 50 GHz at temperatures 30 - 300K. Na0.5K0.5NbO3/SiO2/Si structures on high resistivity silicon substrate exhibit C-V performances typical for Metal-Insulator- Semiconductor (MIS) capacitors. At low frequencies, f 1.0 GHz, the large tuneability and large losses are associated with the MIS structure, while at higher microwave frequencies the tuneability is mainly associated with the ferroelectric, film. At 1.0 MHz and room temperature, the tuneability of Na0.5K0.5NbO3/SiO2/Si structures more than 90%, reducing to 10-15 % at 50 GHz. The losses decrease with increasing the DC bias and frequency. A Q-factor more than 15 at 50 GHz is observed. The dielectric permittivity of the Na0.5K0.5NbO3 film is in the range 50-150 at frequencies 0.045-50 GHz. On low resistivity substrate the performance of Na0.5K0.5NbO3 films is completely screened by the high losses in silicon, and the tuneability is negligible. © 2001 Taylor and Francis.

  • 22.
    Aban, Kevin
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Göst, Jens
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Analysis of transports with pharmaceuticals on Arlanda airport2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Rapporten syftar till att kartlägga och analysera dagens transportflöde av läkemedel på fraktområdet Cargo City på Arlanda. Cargo Center och APH Logistics är två fraktagenter som har sin verksamhet på Cargo City. Observera att Cargo City och Cargo Center inte har samma innebörd. Cargo Center och APH Logistics erbjuder genom nära samarbete transport och hantering av temperaturkänsligt gods, som till exempel läkemedel. Läkemedel är värdefullt gods som kräver särskild skötsel vid transport, hantering och förvaring. Det ställer stränga krav på samtliga aktörer i försörjningskedjan. Genom studiebesök och intervjuer har författarna kartlagt det befintliga flödet av läkemedel. SACT, ett åkeri och dotterbolag till Cargo Center, utför transporten av godset till Cargo City med nerkylda lastbilar. APH Logistics omlastningsterminal på Cargo City är temperaturkontrollerad, vilket innebär att läkemedelsgodset förvaras och lastats i flygcontainrar där. Det färdiglastade godset forslas sedan vidare till Cargo Centers terminal. Där sker vikt- och volymkontroll av godset, det registreras i olika datasystem och slutligen märks det med etiketter, så som flygfraktsedeln. Mycket av godset som hanteras på Arlanda körs med lastbil till andra flygplatser och destinationer runt om i Europa istället för att flygfraktas direkt från flygplatsen. Dessutom hanteras och förvaras inte allt läkemedelsgods under temperaturkontrollerade former. En totalkostnadsanalys har gjorts för att jämföra olika transportflödesscenarion. Dessutom har författarna identifierat den kundservice Cargo Center och APH Logistics bör erbjuda kunden. Den bygger på kvalitativa resonemang. Resultatet av rapporten är författarnas rekommendation till företagen av hur de bör gå tillväga i framtiden. Den ger både kortsiktiga och långsiktiga tips.

    Fulltekst (pdf)
    fulltext
  • 23.
    Abara, Precious Ugo
    et al.
    Univ Padua, Italy; Tech Univ Munich, Germany.
    Ticozzi, Francesco
    Univ Padua, Italy; Dartmouth Coll, NH 03755 USA.
    Altafini, Claudio
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Spectral Conditions for Stability and Stabilization of Positive Equilibria for a Class of Nonlinear Cooperative Systems2018Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 63, nr 2, s. 402-417Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nonlinear cooperative systems associated to vector fields that are concave or subhomogeneous describe well interconnected dynamics that are of key interest for communication, biological, economical, and neural network applications. For this class of positive systems, we provide conditions that guarantee existence, uniqueness and stability of strictly positive equilibria. These conditions can be formulated directly in terms of the spectral radius of the Jacobian of the system. If control inputs are available, then it is shown how to use state feedback to stabilize an equilibrium point in the interior of the positive orthant.

    Fulltekst (pdf)
    fulltext
  • 24.
    Abarghouyi, Hadis
    et al.
    IUST, Iran; MTNi Co, Iran.
    Razavizadeh, S. Mohammad
    IUST, Iran.
    Björnson, Emil
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska fakulteten.
    QoE-Aware Beamforming Design for Massive MIMO Heterogeneous Networks2018Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 67, nr 9, s. 8315-8323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the main goals of the future wireless networks is improving the users quality of experience (QoE). In this paper, we consider the problem of the QoE-based resource allocation in the downlink of a massive multiple-input multiple-output heterogeneous network. The network consists of a macrocell with a number of small cells embedded in it. The small cells base stations (BSs) are equipped with a few antennas, while the macro BS is equipped with a massive number of antennas. We consider the two services Video and Web Browsing and design the beamforming vectors at the BSs. The objective is to maximize the aggregated mean opinion score (MOS) of the users under constraints on the BSs powers and the required quality of service of the users. We also consider extra constraints on the QoE of users to more strongly enforce the QoE in the beamforming design. To reduce the complexity of the optimization problem, we suggest suboptimal and computationally efficient solutions. Our results illustrate that increasing the number of antennas at the BSs and also increasing the number of small cells antennas in the network leads to a higher user satisfaction.

  • 25.
    Abarkan, Myriam
    et al.
    Univ Bordeaux, France.
    Pirog, Antoine
    Univ Bordeaux, France.
    Mafilaza, Donnie
    Univ Bordeaux, France.
    Pathak, Gaurav
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. MOC, France.
    NKaoua, Gilles
    Univ Bordeaux, France.
    Puginier, Emilie
    Univ Bordeaux, France.
    OConnor, Rodney
    MOC, France.
    Raoux, Matthieu
    Univ Bordeaux, France.
    Donahue, Mary
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. MOC, France.
    Renaud, Sylvie
    Univ Bordeaux, France.
    Lang, Jochen
    Univ Bordeaux, France.
    Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro-Organ Signals2022Inngår i: Advanced Science, E-ISSN 2198-3844, Vol. 9, nr 8, artikkel-id 2105211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS-based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro-organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single-cell action potentials and multicellular slow potentials reflecting micro-organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.

    Fulltekst (pdf)
    fulltext
  • 26.
    Abbas, Malik Waseem
    et al.
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Soomro, Razium Ali
    Natl Inst Biotechnol and Genet Engn, Pakistan; Univ Sindh, Pakistan; Univ Bristol, England.
    Kalwar, Nazar Hussain
    Shah Abdul Latif Univ, Pakistan.
    Zahoor, Mehvish
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Avci, Ahmet
    Selcuk Univ, Turkey.
    Pehlivan, Erol
    Selcuk Univ, Turkey.
    Hallam, Keith Richard
    Univ Bristol, England.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Carbon quantum dot coated Fe3O4 hybrid composites for sensitive electrochemical detection of uric acid2019Inngår i: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 146, s. 517-524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe3O4 nanoparticles (Fe3O4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe3O4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe3O4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe3O4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 mu M and signal sensitivity measurable up to 6.0 x 10(-9) M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe3O4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

  • 27. Bestill onlineKjøp publikasjonen >>
    Abbas, Muhammad
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    On the Implementation of Integer and Non-Integer Sampling Rate Conversion2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The main focus in this thesis is on the aspects related to the implementation of integer and non-integer sampling rate conversion (SRC). SRC is used in many communication and signal processing applications where two signals or systems having different sampling rates need to be interconnected. There are two basic approaches to deal with this problem. The first is to convert the signal to analog and then re-sample it at the desired rate. In the second approach, digital signal processing techniques are utilized to compute values of the new samples from the existing ones. The former approach is hardly used since the latter one introduces less noise and distortion. However, the implementation complexity for the second approach varies for different types of conversion factors. In this work, the second approach for SRC is considered and its implementation details are explored. The conversion factor in general can be an integer, a ratio of two integers, or an irrational number. The SRC by an irrational numbers is impractical and is generally stated for the completeness. They are usually approximated by some rational factor.

    The performance of decimators and interpolators is mainly determined by the filters, which are there to suppress aliasing effects or removing unwanted images. There are many approaches for the implementation of decimation and interpolation filters, and cascaded integrator comb (CIC) filters are one of them. CIC filters are most commonly used in the case of integer sampling rate conversions and often preferred due to their simplicity, hardware efficiency, and relatively good anti-aliasing (anti-imaging) characteristics for the first (last) stage of a decimation (interpolation). The multiplierless nature, which generally yields to low power consumption, makes CIC filters well suited for performing conversion at higher rate. Since these filters operate at the maximum sampling frequency, therefore, are critical with respect to power consumption. It is therefore necessary to have an accurate and efficient ways and approaches that could be utilized to estimate the power consumption and the important factors that are contributing to it. Switching activity is one such factor. To have a high-level estimate of dynamic power consumption, switching activity equations in CIC filters are derived, which may then be used to have an estimate of the dynamic power consumption. The modeling of leakage power is also included, which is an important parameter to consider since the input sampling rate may differ several orders of magnitude. These power estimates at higher level can then be used as a feed-back while exploring multiple alternatives.

    Sampling rate conversion is a typical example where it is required to determine the values between existing samples. The computation of a value between existing samples can alternatively be regarded as delaying the underlying signal by a fractional sampling period. The fractional-delay filters are used in this context to provide a fractional-delay adjustable to any desired value and are therefore suitable for both integer and non-integer factors. The structure that is used in the efficient implementation of a fractional-delay filter is know as Farrow structure or its modifications. The main advantage of the Farrow structure lies in the fact that it consists of fixed finite-impulse response (FIR) filters and there is only one adjustable fractional-delay parameter, used to evaluate a polynomial with the filter outputs as coefficients. This characteristic of the Farrow structure makes it a very attractive structure for the implementation. In the considered fixed-point implementation of the Farrow structure, closed-form expressions for suitable word lengths are derived based on scaling and round-off noise. Since multipliers share major portion of the total power consumption, a matrix-vector multiple constant multiplication approach is proposed to improve the multiplierless implementation of FIR sub-filters.

    The implementation of the polynomial part of the Farrow structure is investigated by considering the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained and used to short list the suitable candidates. Most of these evaluation schemes require the explicit computation of higher order power terms. In the parallel evaluation of powers, redundancy in computations is removed by exploiting any possible sharing at word level and also at bit level. As a part of this, since exponents are additive under multiplication, an ILP formulation for the minimum addition sequence problem is proposed.

    Delarbeid
    1. Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology
    Åpne denne publikasjonen i ny fane eller vindu >>Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology
    2010 (engelsk)Inngår i: Proceedings of International Conference on Green Circuits and Systems (ICGCS), 2010, Date: 21-23 June, 2010, IEEE , 2010, s. 221-225Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    The power modeling of different realizations of cascaded integrator-comb (CIC) decimation filters has been a subject of several recent works. In this work we have extended these with modeling of leakage power, which is an important factor since the input sample rate may differ several orders of magnitude. Furthermore, we have pointed out the importance of the input wordlength on the comparison of recursive and nonrecursive implementations.

    sted, utgiver, år, opplag, sider
    IEEE, 2010
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-70451 (URN)10.1109/ICGCS.2010.5543063 (DOI)978-1-4244-6877-5 (ISBN)978-1-4244-6876-8 (ISBN)
    Konferanse
    International Conference on Green Circuits and Systems (ICGCS), June 21–23, Shanghai, China
    Tilgjengelig fra: 2011-09-20 Laget: 2011-09-08 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    2. Switching Activity Estimation of CIC Filter Integrators
    Åpne denne publikasjonen i ny fane eller vindu >>Switching Activity Estimation of CIC Filter Integrators
    2010 (engelsk)Inngår i: Proceedings of Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), 2010, Date:22-24 Sept. 2010, IEEE , 2010, s. 21-24Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters.

    sted, utgiver, år, opplag, sider
    IEEE, 2010
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-70452 (URN)10.1109/PRIMEASIA.2010.5604971 (DOI)978-1-4244-6736-5 (ISBN)978-1-4244-6735-8 (ISBN)
    Konferanse
    Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), 22-24 September, Shanghai, China
    Merknad
    ©2010 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. MUHAMMAD ABBAS and Oscar Gustafsson, Switching Activity Estimation of CIC Filter Integrators, 2010, Asia Pacific Conf. on Postgraduate Research in Microelectronics and Electronics, Shanghai, China. http://dx.doi.org/10.1109/PRIMEASIA.2010.5604971 Tilgjengelig fra: 2011-09-20 Laget: 2011-09-08 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    3. Scaling of fractional delay filters based on the Farrow structure
    Åpne denne publikasjonen i ny fane eller vindu >>Scaling of fractional delay filters based on the Farrow structure
    2009 (engelsk)Inngår i: Proceedings of IEEE International Symposium on Circuits and Systems, 2009. ISCAS 2009, Piscataway: IEEE , 2009, s. 489-492Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work we consider scaling of fractional delay filters using the Farrow structure. Based on the observation that the subfilters approximate the Taylor expansion of a differentiator, we derive estimates of the L2-norm scaling values at the outputs of each subfilter as well as at the inputs of each delay multiplier. The scaling values can then be used to derive suitable wordlengths in a fixed-point implementation.

    sted, utgiver, år, opplag, sider
    Piscataway: IEEE, 2009
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-51070 (URN)10.1109/ISCAS.2009.5117792 (DOI)000275929800123 ()978-1-4244-3827-3 (ISBN)
    Konferanse
    IEEE International Symposium on Circuits and Systems, 24-27 May 2009, Taipei,Taiwan
    Tilgjengelig fra: 2009-10-15 Laget: 2009-10-15 Sist oppdatert: 2018-09-01bibliografisk kontrollert
    4. Computational and Implementation Complexity of Polynomial Evaluation Schemes
    Åpne denne publikasjonen i ny fane eller vindu >>Computational and Implementation Complexity of Polynomial Evaluation Schemes
    2011 (engelsk)Inngår i: Proceedings of NORCHIP, 2011 Date:14-15 Nov. 2011, IEEE conference proceedings, 2011, s. 1-6Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work, we consider the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained. These can then be used to short list suitable candidates for an implementation given the specifications. Not only multiplications are considered, but they are divided into data-data multiplications, squarers, and data-coefficient multiplications, as the latter can be optimized depending on implementation architecture and application.

    sted, utgiver, år, opplag, sider
    IEEE conference proceedings, 2011
    Emneord
    Adders, Computer architecture, Delay, Filtering algorithms, ISO, Pipeline processing, Polynomials
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73935 (URN)10.1109/NORCHP.2011.6126735 (DOI)978-1-4577-0515-1 (ISBN)978-1-4577-0514-4 (ISBN)
    Konferanse
    NORCHIP 2011. The Nordic Microelectronics event, 29th Norchip Conference 14-15 November 2011, Lund, Sweden
    Tilgjengelig fra: 2012-01-17 Laget: 2012-01-17 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    5. Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy
    Åpne denne publikasjonen i ny fane eller vindu >>Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy
    2010 (engelsk)Inngår i: Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010 / [ed] Michael B. Matthews, Washington, DC, USA: IEEE Computer Society , 2010, s. 1168-1172Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work, we investigate the problem of computing any requested set of power terms in parallel using summations trees. This problem occurs in applications like polynomial approximation, Farrow filters (polynomial evaluation part) etc. In the proposed technique, the partial product of each power term is initially computed independently. A redundancy check is then made in each and among all partial products matrices at bit level. The redundancy here relates to the fact that same three partial products may be present in more than one columns, and, hence, can be mapped to the same full adder. The proposed algorithm is tested for different sets of powers and wordlengths to exploit the sharing potential.

    sted, utgiver, år, opplag, sider
    Washington, DC, USA: IEEE Computer Society, 2010
    Serie
    Asilomar Conference on Signals, Systems and Computers. Conference Record, ISSN 1058-6393
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-70453 (URN)10.1109/ACSSC.2010.5757714 (DOI)978-1-4244-9722-5 (ISBN)
    Konferanse
    Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010 , Pacific Grove, CA, USA
    Tilgjengelig fra: 2011-09-20 Laget: 2011-09-08 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    6. Integer Linear Programming Modeling of Addition Sequences With Additional Constraints for Evaluation of Power Terms
    Åpne denne publikasjonen i ny fane eller vindu >>Integer Linear Programming Modeling of Addition Sequences With Additional Constraints for Evaluation of Power Terms
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this work, an integer linear programming (ILP) based model is proposed for the computation of a minimal cost addition sequence for a given set of integers. Since exponents are additive under multiplication, the minimal length addition sequence will provide an optimal solution for the evaluation of a requested set of power terms. This in turn finds application in, e.g., window-based exponentiation for cryptography and polynomial evaluation. Not only is an optimal model proposed, the model is extended to consider different costs for multipliers and squarers as well as controlling the depth of the resulting addition sequence.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73936 (URN)
    Tilgjengelig fra: 2012-01-17 Laget: 2012-01-17 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    7. Switching Activity Estimation of DDFS Phase Accumulators
    Åpne denne publikasjonen i ny fane eller vindu >>Switching Activity Estimation of DDFS Phase Accumulators
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this letter, equations for the one’s probability and switching activities for direct digital frequency synthesis (DDFS) phase accumulators are derived. These results are useful for obtaining good accuracy estimated of both leakage and dynamic power consumption for the phase accumulator and the phase-to-magnitude converter.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73937 (URN)
    Tilgjengelig fra: 2012-01-17 Laget: 2012-01-17 Sist oppdatert: 2015-03-11bibliografisk kontrollert
    Fulltekst (pdf)
    On the Implementation of Integer and Non-Integer Sampling Rate Conversion
    Download (pdf)
    omslag
  • 28.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Computational and Implementation Complexity of Polynomial Evaluation Schemes2011Inngår i: Proceedings of NORCHIP, 2011 Date:14-15 Nov. 2011, IEEE conference proceedings, 2011, s. 1-6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, we consider the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained. These can then be used to short list suitable candidates for an implementation given the specifications. Not only multiplications are considered, but they are divided into data-data multiplications, squarers, and data-coefficient multiplications, as the latter can be optimized depending on implementation architecture and application.

  • 29.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Integer Linear Programming Modeling of Addition Sequences With Additional Constraints for Evaluation of Power TermsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this work, an integer linear programming (ILP) based model is proposed for the computation of a minimal cost addition sequence for a given set of integers. Since exponents are additive under multiplication, the minimal length addition sequence will provide an optimal solution for the evaluation of a requested set of power terms. This in turn finds application in, e.g., window-based exponentiation for cryptography and polynomial evaluation. Not only is an optimal model proposed, the model is extended to consider different costs for multipliers and squarers as well as controlling the depth of the resulting addition sequence.

  • 30.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Switching Activity Estimation of CIC Filter Integrators2010Inngår i: Proceedings of Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), 2010, Date:22-24 Sept. 2010, IEEE , 2010, s. 21-24Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters.

    Fulltekst (pdf)
    fulltext
  • 31.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Switching Activity Estimation of DDFS Phase AccumulatorsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this letter, equations for the one’s probability and switching activities for direct digital frequency synthesis (DDFS) phase accumulators are derived. These results are useful for obtaining good accuracy estimated of both leakage and dynamic power consumption for the phase accumulator and the phase-to-magnitude converter.

  • 32.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Blad, Anton
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy2010Inngår i: Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010 / [ed] Michael B. Matthews, Washington, DC, USA: IEEE Computer Society , 2010, s. 1168-1172Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, we investigate the problem of computing any requested set of power terms in parallel using summations trees. This problem occurs in applications like polynomial approximation, Farrow filters (polynomial evaluation part) etc. In the proposed technique, the partial product of each power term is initially computed independently. A redundancy check is then made in each and among all partial products matrices at bit level. The redundancy here relates to the fact that same three partial products may be present in more than one columns, and, hence, can be mapped to the same full adder. The proposed algorithm is tested for different sets of powers and wordlengths to exploit the sharing potential.

  • 33.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Johansson, Håkan
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    On the Fixed-Point Implementation of Fractional-Delay Filters Based on the Farrow Structure2013Inngår i: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 60, nr 4, s. 926-937Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, the fixed-point implementation of adjustable fractional-delay filters using the Farrow structure is considered. Based on the observation that the sub-filters approximate differentiators, closed-form expressions for the L-2-norm scaling values at the outputs of each sub-filter as well as at the inputs of each delay multiplier are derived. The scaling values can then be used to derive suitable word lengths by also considering the round-off noise analysis and optimization. Different approaches are proposed to derive suitable word lengths including one based on integer linear programming, which always gives an optimal allocation. Finally, a new approach for multiplierless implementation of the sub-filters in the Farrow structure is suggested. This is shown to reduce register complexity and, for most word lengths, require less number of adders and subtracters when compared to existing approaches.

  • 34.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Johansson, Håkan
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Scaling of fractional delay filters based on the Farrow structure2009Inngår i: Proceedings of IEEE International Symposium on Circuits and Systems, 2009. ISCAS 2009, Piscataway: IEEE , 2009, s. 489-492Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work we consider scaling of fractional delay filters using the Farrow structure. Based on the observation that the subfilters approximate the Taylor expansion of a differentiator, we derive estimates of the L2-norm scaling values at the outputs of each subfilter as well as at the inputs of each delay multiplier. The scaling values can then be used to derive suitable wordlengths in a fixed-point implementation.

  • 35.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wanhammar, Lars
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology2010Inngår i: Proceedings of International Conference on Green Circuits and Systems (ICGCS), 2010, Date: 21-23 June, 2010, IEEE , 2010, s. 221-225Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The power modeling of different realizations of cascaded integrator-comb (CIC) decimation filters has been a subject of several recent works. In this work we have extended these with modeling of leakage power, which is an important factor since the input sample rate may differ several orders of magnitude. Furthermore, we have pointed out the importance of the input wordlength on the comparison of recursive and nonrecursive implementations.

  • 36.
    Abbas, Muhammad
    et al.
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska högskolan.
    Qureshi, Fahad
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska högskolan.
    Ullah Sheikh, Zaka
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Johansson, Håkan
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Johansson, Kenny
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Comparison of Multiplierless Implementation of Nonlinear-Phase Versus Linear-Phase FIR filters2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    FIR filters are often used because of their linear-phase response. However, there are certain applications where the linear-phase property is not required, such as signal energy estimation, but IIR filters can not be used due to the limitation of sample rate imposed by the recursive algorithm. In this work, we discuss multiplierless implementation of minimum order, and therefore nonlinear-phase, FIR filters and compare it to the linear-phase counterpart.

  • 37.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fabrication of UV photo-detector based on coral reef like p-NiO/n-ZnO nanocomposite structures2013Inngår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 108, s. 149-152Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this research work, a UV photo-detector is fabricated on fluorine doped tin oxide (FTO) glass substrate by exploiting the advantageous features of p-n heterojunctions based on p-NiO and n-ZnO composite nanostructures forming a coral-reef like structures. Scanning electron microscopy (SEM) and X-ray diffraction results showed uniform morphology and good crystal quality of the synthesised nanostructures respectively. I-V measurements have shown nonlinear and rectifying response of the p-NiO/n-ZnO heterojunction. The proposed photodiode exhibited excellent UV response with acceptable photocurrent generation of about 3.4 mA and the responsivity of 2.27 A/W at -3 biasing voltage.

  • 38.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    National Centre for Physics, Islamabad, Pakistan .
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Iron (III) Ion Sensor Based on the Seedless Grown ZnO Nanorods in 3 Dimensions Using Nickel Foam Substrate2013Inngår i: Journal of Sensors, ISSN 1687-725X, E-ISSN 1687-7268, nr 382726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, the seedless, highly aligned and vertical ZnO nanorods in 3 dimensions (3D) were grown on the nickel foam substrate. The seedless grown ZnO nanorods were characterised by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) techniques. The characterised seedless ZnO nanorods in 3D on nickel foam were highly dense, perpendicular to substrate, grown along the (002) crystal plane, and also composed of single crystal. In addition to this, these seedless ZnO nanorods were functionalized with trans-dinitro-dibenzo-18-6 crown ether, a selective iron (III) ion ionophore, along with other components of membrane composition such as polyvinyl chloride (PVC), 2-nitopentylphenyl ether as plasticizer (NPPE), and tetrabutyl ammonium tetraphenylborate (TBATPB) as conductivity increaser. The sensor electrode has shown high linearity with a wide range of detection of iron (III) ion concentrations from 0.005 mM to 100 mM. The low limit of detection of the proposed ion selective electrode was found to be 0.001 mM. The proposed sensor also described high storage stability, selectivity, reproducibility, and repeatability and a quick response time of less than 10 s.

    Fulltekst (pdf)
    fulltext
  • 39.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ibupoto, Zafar Hussain
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain, Mushtaque
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    Quaid-e-Azam University Campus, Islamabad, Pakistan.
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures2012Inngår i: Sensors, E-ISSN 1424-8220, Vol. 12, nr 11, s. 15424-15437Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

    Fulltekst (pdf)
    fulltext
  • 40.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    National Centre for Physics, Quaid-e-Azam University Campus, Islamabad, Pakistan .
    Hussain, Sajjad
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Anions effect on the low temperature growth of ZnO nanostructures2012Inngår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, nr 12, s. 1998-2001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seed mediated aqueous chemical growth (ACG) route was used for the growth of ZnO nanostructures on Si substrate in four different growth mediums. The growth medium has shown to affect the morphology and the size of the different nanostructures. We observed that the medium containing zinc nitrate anions yields the nanorods, in a medium containing zinc acetate anions nano-candles are obtained. While in a medium containing zinc chloride anions ZnO nano-discs were obtained and in a medium containing zinc sulfate anions nano-flakes are achieved. Growth in these different mediums has also shown effect on the optical emission characteristics of the different ZnO nanostructures.

    Fulltekst (pdf)
    fulltext
  • 41.
    Abbasi, Muneeb Mehmood
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Jabbar, Mohammad Abdul
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Design and Performance Analysis of Low-Noise Amplifier with Band-Pass Filter for 2.4-2.5 GHz2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Low power wireless electronics is becoming more popular due to durability, portability and small dimension. Especially, electronic devices in instruments, scientific and medical (ISM) band is convenient from the spectrum regulations and technology availability point of view. In the communication engineering society, to make a robust transceiver is always a matter of challenges for the better performance.

    However, in this thesis work, a new approach of design and performance analysis of Low-Noise Amplifier with Band-Pass filter is performed at 2.45 GHz under the communication electronics research group of Institute of Science and Technology (ITN). Band-Pass Filtered Low-Noise Amplifier is designed with lumped components and transmission lines. Performances of different designs are compared with respect to noise figure, gain, input and output reflection coefficient. In the design process, a single stage LNA is designed with amplifier, ATF-58143. Maximally flat band-pass (BPF) filters were designed with lumped components and distributed elements. Afterwards, BPF is integrated with the LNA at the front side of LNA to get a compact Band-Pass Filtered Low-Noise Amplifier with good performance.

    Advanced Design System (ADS) tool was used for design and simulation, and each design was tuned to get the optimum value for noise figure, gain and input reflection coefficient. LNA stand-alone gives acceptable value of noise figure and gain but the bandwidth was too wide compared to specification. Band-Pass Filtered Low-Noise Amplifier with lumped components gives also considerable values of noise and gain. But the gain was not so flat and the bandwidth was also wide. Then, Band-Pass Filtered Low-Noise Amplifier was designed with transmission lines where the optimum value of noise figure and gain was found. The gain was almost flat over the whole band, i.e., 2.4-2.5 GHz compared to LNA stand-alone and Band-Pass Filtered Low-Noise Amplifier designed with lumped components. It is observed that deviations of results from schematic to layout level are considerable, i.e., electromagnetic simulation is needed to predict the Band-Pass Filtered Low-Noise Amplifier performance.

    Prototype of LNA, Band-Pass Filtered Low-Noise Amplifier with lumped and transmission lines are made at ITN’s PCB laboratory. Due to unavailability of exact values of Murata components and for some other technical reasons, the measured values of Band-Pass Filtered Low-Noise Amplifier with lumped components and transmission lines are deviated compared to predicted values from simulation.

    Fulltekst (pdf)
    fulltext
  • 42.
    Abbasi, Rizwan
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    A Framework For Interacting With Parameterized and Infinite State Verification Tools2013Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    We develop a tool to explore the behavior of parameterized systems (i.e., systems consisting of an arbitrary number of identical processes that synchronize using shared variables or global communications) and to ease user interaction with tools that verify them. The tool includes a user friendly GUI that allows the user to describe a parameterized system and to perform guided, interactive or random simulation. This tool empowers the user to plug in several independent verifiers to perform verification. A mockup verifier is developed in order to facilitate the development of the tool and testing the required functionalities. The mockup verifier involves parsing descriptions of the parameterized systems to be analyzed. In order to interact with the verifier, the tool is user friendly and flexible in the sense that the user can plug in a verifier developed in any language as long as it allows to perform a number of basic computations on the parameterized system (such as the set of enabled transitions or the set of successor configurations). In order to plug in a new tool, our tool needs to be able to make use of these operations, for instance using a wrapper written for a verifier particular to a class of parameterized systems. Given these operations, our tool enables the user to carry out various types of simulations like random, interactive or guided simulations. Moreover, our tool can submit verification queries to the underlying verifier and walk the user through the generated counter examples as if it was a simulation session.

    Fulltekst (pdf)
    Thesis Report Rizwan_final - ep
  • 43.
    Abbasi, Saad Zeb
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Automatic Test Builder2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In Ericsson, the Automation Team automates test cases that are frequently rerun. This process involves copying data related to a particular Configured Test Case from a database and then pasting it into a java file created to run a test case. In one java file, there can be more than one Configured Test Cases. So information can vary. Then the tester has to add package name, necessary imports, member variables, preamble and post amble methods, help methods and main execution methods. A lot of time and effort are consumed in writing the whole code. The Automation Team came up with a proposal of having a tool that can generate this whole information and the tester just has to add or remove minor changes. This will save time and resources. So the development of tool started and finally a tool named Automatic Test Builder developed in java was created to help automation teams in Ottawa, Kista and Linkoping.

    This document elaborates problem statement, opted approach, tools used in development process, a detailed overview of all development stages of Automatic Test Builder. This document also explains issues what came during the development, evaluation and usability analysis of Automatic Test Builder.

    Fulltekst (pdf)
    Thesis Report
  • 44.
    Abbatelli, Daniele
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Material flows in the waterjet industry: an environmental perspective2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Abrasive Waterjet cutting (AWJ) presents many advantages over competing machining techniques, but several issues are related to the high volume of materials (and in particular of abrasive) used in the process.

    In this study, the environmental impact of the material flows in the abrasive waterjet industry has been analyzed adopting a life cycle perspective in order to individuate which phases place the largest burden on the environment. Moreover, three alternative abrasives (crushed rock, recycled glass and synthetic abrasive) and three disposal practices (in-site recycling, off-site recycling and recycling as construction material) have been also evaluated to estimate the benefits that can be achieved if these could be used in place of garnet abrasives and landfilling.

    The transportation of the abrasive resulted to be the phase that has the largest influence in every case and thus should be reduced as much as possible. For what concerns the alternative options, the usage of recycled glass and the in-site recycling of the abrasive were the two alternatives with the best environmental performances. However, crushed rock could be the best option for what concerns the global warming potential if carbon sequestration due to carbonation of silicate rocks is taken into account. Off-site recycling and recycling as construction material are good options only if the transportation to the recycling site can be reduced. Synthetic abrasive are instead found to have a much larger impact compared to every other alternative examined.

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  • 45.
    Abdella, Juhar Ahmed
    et al.
    UAEU, U Arab Emirates.
    Zaki, N. M.
    UAEU, U Arab Emirates.
    Shuaib, Khaled
    UAEU, U Arab Emirates.
    Khan, Fahad
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Airline ticket price and demand prediction: A survey2021Inngår i: Journal of King Saud University - Computer and Information Sciences, ISSN 1319-1578, Vol. 33, nr 4, s. 375-391Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nowadays, airline ticket prices can vary dynamically and significantly for the same flight, even for nearby seats within the same cabin. Customers are seeking to get the lowest price while airlines are trying to keep their overall revenue as high as possible and maximize their profit. Airlines use various kinds of computational techniques to increase their revenue such as demand prediction and price discrimination. From the customer side, two kinds of models are proposed by different researchers to save money for customers: models that predict the optimal time to buy a ticket and models that predict the minimum ticket price. In this paper, we present a review of customer side and airlines side prediction models. Our review analysis shows that models on both sides rely on limited set of features such as historical ticket price data, ticket purchase date and departure date. Features extracted from external factors such as social media data and search engine query are not considered. Therefore, we introduce and discuss the concept of using social media data for ticket/demand prediction. (c) 2019 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

    Fulltekst (pdf)
    fulltext
  • 46.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    A Reinforcement Learning Framework for Optimizing Age of Information in RF-Powered Communication Systems2020Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 68, nr 8, s. 4747-4760Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we study a real-time monitoring system in which multiple source nodes are responsible for sending update packets to a common destination node in order to maintain the freshness of information at the destination. Since it may not always be feasible to replace or recharge batteries in all source nodes, we consider that the nodes are powered through wireless energy transfer (WET) by the destination. For this system setup, we investigate the optimal online sampling policy (referred to as the age-optimal policy) that jointly optimizes WET and scheduling of update packet transmissions with the objective of minimizing the long-term average weighted sum of Age of Information (AoI) values for different physical processes (observed by the source nodes) at the destination node, referred to as the sum-AoI. To solve this optimization problem, we first model this setup as an average cost Markov decision process (MDP) with finite state and action spaces. Due to the extreme curse of dimensionality in the state space of the formulated MDP, classical reinforcement learning algorithms are no longer applicable to our problem even for reasonable-scale settings. Motivated by this, we propose a deep reinforcement learning (DRL) algorithm that can learn the age-optimal policy in a computationally-efficient manner. We further characterize the structural properties of the age-optimal policy analytically, and demonstrate that it has a threshold-based structure with respect to the AoI values for different processes. We extend our analysis to characterize the structural properties of the policy that maximizes average throughput for our system setup, referred to as the throughput-optimal policy. Afterwards, we analytically demonstrate that the structures of the age-optimal and throughput-optimal policies are different. We also numerically demonstrate these structures as well as the impact of system design parameters on the optimal achievable average weighted sum-AoI.

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    fulltext
  • 47.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    AoI-Optimal Joint Sampling and Updating for Wireless Powered Communication Systems2020Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 69, nr 11, s. 14110-14115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper characterizes the structure of the Age of Information (AoI)-optimal policy in wireless powered communication systems while accounting for the time and energy costs of generating status updates at the source nodes. In particular, for a single source-destination pair in which a radio frequency (RF)-powered source sends status updates about some physical process to a destination node, we minimize the long-term average AoI at the destination node. The problem is modeled as an average cost Markov Decision Process (MDP) in which, the generation times of status updates at the source, the transmissions of status updates from the source to the destination, and the wireless energy transfer (WET) are jointly optimized. After proving the monotonicity property of the value function associated with the MDP, we analytically demonstrate that the AoI-optimal policy has a threshold-based structure w.r.t. the state variables. Our numerical results verify the analytical findings and reveal the impact of state variables on the structure of the AoI-optimal policy. Our results also demonstrate the impact of system design parameters on the optimal achievable average AoI as well as the superiority of our proposed joint sampling and updating policy w.r.t. the generate-at-will policy.

    Fulltekst (pdf)
    fulltext
  • 48.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Online Age-minimal Sampling Policy for RF-powered IoT Networks2019Inngår i: 2019 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we study a real-time Internet of Things (IoT)-enabled monitoring system in which a source node (e.g., IoT device or an aggregator located near a group of IoT devices) is responsible for maintaining the freshness of information status at a destination node by sending update packets. Since it may not always be feasible to replace or recharge batteries in all IoT devices, we consider that the source node is powered by wireless energy transfer (WET) by the destination. For this system setup, we investigate the optimal online sampling policy that minimizes the long-term average Age-of-Information (AoI), referred to as the age-optimal policy. The age-optimal policy determines whether each slot should be allocated for WET or update packet transmission while considering the dynamics of battery level, AoI, and channel state information (CSI). To solve this optimization problem, we model this setup as an average cost Markov Decision Process (MDP). After analytically establishing the monotonicity property of the value function associated with the MDP, the age-optimal policy is proven to be a threshold based policy with respect to each of the system state variables. We extend our analysis to characterize the structural properties of the policy that maximizes average throughput for our system setup, referred to as the throughput-optimal policy. Afterwards, we analytically demonstrate that the structures of the age optimal and throughput-optimal policies are different. We also numerically demonstrate these structures as well as the impact of system design parameters on the optimal achievable average AoI.

  • 49.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Dhillon, Arpreet S.
    Virginia Tech, VA 24061 USA.
    On the Role of Age of Information in the Internet of Things2019Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 57, nr 12, s. 72-77Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we provide an accessible introduction to the emerging idea of Age of Information (AoI) that quantifies freshness of information and explore its possible role in the efficient design of freshness-aware Internet of Things (IoT). We start by summarizing the concept of AoI and its variants with emphasis on the differences between AoI and other well-known performance metrics in the literature, such as throughput and delay. Building on this, we explore freshness-aware IoT design for a network in which IoT devices sense potentially different physical processes and are supposed to frequently update the status of these processes at a destination node (e.g., a cellular base station). Inspired by recent interest, we also assume that these IoT devices are powered by wireless energy transfer by the destination node. For this setting, we investigate the optimal sampling policy that jointly optimizes wireless energy transfer and scheduling of update packet transmissions from IoT devices with the goal of minimizing long-term weighted sum-AoI. Using this, we characterize the achievable AoI region. We also compare this AoI-optimal policy with the one that maximizes average throughput (throughput-optimal policy), and demonstrate the impact of system state on their structures. Several promising directions for future research are also presented.

    Fulltekst (pdf)
    fulltext
  • 50.
    Abdollahi Sani, Negar
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Mirbel, Deborah
    Univ Bordeaux, France.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Simon, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Brochon, Cyril
    Univ Bordeaux, France.
    Cloutet, Eric
    Univ Bordeaux, France.
    Hadziioannou, Georges
    Univ Bordeaux, France.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    A ferroelectric polymer introduces addressability in electrophoretic display cells2019Inngår i: FLEXIBLE AND PRINTED ELECTRONICS, ISSN 2058-8585, Vol. 4, nr 3, artikkel-id 035004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During the last decades, tremendous efforts have been carried out to develop flexible electronics for a vast array of applications. Among all different applications investigated in this area, flexible displays have gained significant attention, being a vital part of large-area devices, portable systems and electronic labels etc electrophoretic (EP) ink displays have outstanding properties such as a superior optical switch contrast and low power consumption, besides being compatible with flexible electronics. However, the EP ink technology requires an active matrix-addressing scheme to enable exclusive addressing of individual pixels. EP ink pixels cannot be incorporated in low cost and easily manufactured passive matrix circuits due to the lack of threshold voltage and nonlinearity, necessities to provide addressability. Here, we suggest a simple method to introduce nonlinearity and threshold voltage in EP ink display cells in order to make them passively addressable. Our method exploits the nonlinearity of an organic ferroelectric capacitor that introduces passive addressability in display cells. The organic ferroelectric material poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) is here chosen because of its simple manufacturing protocol and good polarizability. We demonstrate that a nonlinear EP cell with bistable states can be produced by depositing a P(VDF-TrFE) film on the bottom electrode of the display cell. The P(VDF-TrFE) capacitor and the EP ink cell are separately characterized in order to match the surface charge at their respective interfaces and to achieve and optimize bistable operation of display pixels.

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