liu.seSearch for publications in DiVA
Endre søk
Begrens søket
1234567 101 - 150 of 7492
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 101.
    Alam, Syed Asad
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten.
    On the implementation of time-multiplexed frequency-response masking filters2016Inngår i: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 64, nr 15, s. 3933-3944Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The complexity of narrow transition band finite-length impulse response (FIR) filters is high and can be reduced by using frequency-response masking (FRM) techniques. These techniques use a combination of periodic model and, possibly periodic, masking filters. Time-multiplexing is in general beneficial since only rarely does the technology bound maximum obtainable clock frequency and the application determined required sample rate correspond. Therefore, architectures for time-multiplexed FRM filters that benefit from the inherent sparsity of theperiodic filters are introduced in this work.

    We show that FRM filters not only reduces the number of multipliers needed, but also have benefits in terms of memory usage. Despite the total amount of samples to be stored is larger for FRM, it results in fewer memory resources needed in FPGAs and more energy efficient memory schemes in ASICs. In total, the power consumption is significantly reduced compared to a single stage implementation. Furthermore, we show that the choice of the interpolation factor which gives the least complexity for the periodic model filter and subsequent masking filter(s) is a function of the time-multiplexing factor, meaning that the minimum number of multipliers not always correspond to the minimum number of multiplications. Both single-port and dual-port memories are considered and the involved trade-off in number of multipliers and memory complexity is illustrated. The results show that for FPGA implementation, the power reduction ranges from 23% to 68% for the considered examples.

  • 102.
    Alami, Mohsen
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Interval Based Parameter Identification for System Biology2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis studies the problem of parameter identification for system biology. Two methods have been studied. The method of interval analysis uses subpaving as a class of objects to manipulate and store inner and outer approximations of compact sets. This method works well with the model given as a system of differential equations, but has its limitations, since the analytical expression for the solution to the ODE is not always obtainable, which is needed for constructing the inclusion function. The other method, studied, is SDP-relaxation of a nonlinear and non-convex feasibility problem. This method, implemented in the toolbox bio.SDP, works with system of difference equations, obtained using the Euler discretization method. The discretization method is not exact, raising the need of bounding this discretization error. Several methods for bounding this error has been studied. The method of ∞-norm optimization, also called worst-case-∞-norm is applied on the one-step error estimation method.

    The methods have been illustrated solving two system biological problems and the resulting SCP have been compared.

  • 103.
    Albani, Giorgia
    et al.
    University of Milano Bicocca, Italy; Ist Nazl Fis Nucl, Italy.
    Perelli Cippo, Enrico
    CNR, Italy.
    Croci, Gabriele
    University of Milano Bicocca, Italy; Ist Nazl Fis Nucl, Italy.
    Muraro, Andrea
    CNR, Italy.
    Schooneveld, Erik
    Rutherford Appleton Lab, England.
    Scherillo, Antonella
    Rutherford Appleton Lab, England.
    Hall-Wilton, Richard
    European Spallat Source ERIC, Sweden; Mittuniversitetet, Sweden.
    Kanaki, Kalliopi
    European Spallat Source ERIC, Sweden.
    Höglund, Carina
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. European Spallat Source ERIC, Sweden.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Claps, Gerardo
    Ist Nazl Fis Nucl, Italy.
    Murtas, Fabrizio
    Ist Nazl Fis Nucl, Italy.
    Rebai, Marica
    University of Milano Bicocca, Italy; Ist Nazl Fis Nucl, Italy.
    Tardocchi, Marco
    CNR, Italy.
    Gorini, Giuseppe
    University of Milano Bicocca, Italy; CNR, Italy; Ist Nazl Fis Nucl, Italy.
    Evolution in boron-based GEM detectors for diffraction measurements: from planar to 3D converters2016Inngår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 27, nr 11, artikkel-id 115902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The so-called He-3-crisis has motivated the neutron detector community to undertake an intense Ramp;D programme in order to develop technologies alternative to standard He-3 tubes and suitable for neutron detection systems in future spallation sources such as the European spallation source (ESS). Boron-based GEM (gas electron multiplier) detectors are a promising He-3-free technology for thermal neutron detection in neutron scattering experiments. In this paper the evolution of boron-based GEM detectors from planar to 3D converters with an application in diffraction measurements is presented. The use of 3D converters coupled with GEMs allows for an optimization of the detector performances. Three different detectors were used for diffraction measurements on the INES instrument at the ISIS spallation source. The performances of the GEM-detectors are compared with those of conventional He-3 tubes installed on the INES instrument. The conceptual detector with the 3D converter used in this paper reached a count rate per unit area of about 25% relative to the currently installed He-3 tube. Its timing resolution is similar and the signal-to-background ratio (S/B) is 2 times lower.

  • 104.
    Albertos, Pedro
    et al.
    Polytechnical University of Valencia, Spain.
    Goodwin, Graham C.
    University of Newcastle, Australia.
    Isaksson, Alf
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    A Pseudo Linear Regression Algorithm for On-Line Parameter Estimation with Missing Data1992Rapport (Annet vitenskapelig)
  • 105.
    Albrektsson, Jörgen
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Optimisation of Off-Road Transport Missions2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Mines, construction sites, road construction and quarries are examples of applications where construction equipment are used. In a production chain consisting of several construction machines working together, the work needs to be optimised and coordinated to achieve an environmental friendly, energy efficient and productive production. Recent rapid development within positioning services, telematics and human machine interfaces (HMI) opens up for control of individual machines and optimisation of transport missions where several construction machines co-operate.

    The production chain on a work site can be split up in different sub-tasks of which some can be transport missions. Taking off in a transport mission where one wheel loader ("loader" hereinafter) and two articulated haulers ("haulers" hereinafter) co-operate to transport material at a set production rate [ton/h], a method for fuel optimal control is developed. On the mission level, optimal cycle times for individual sub-tasks such as wheel loader loading, hauler transport and hauler return, are established through the usage of Pareto fronts.

    The haulers Pareto fronts are built through the development of a Dynamic Programming (DP) algorithm that trades fuel consumption versus cycle time for a road stretch by means of a time penalty constant. Through varying the time penalty constant n number of times, discrete fuel consumption - cycle time values can be achieved, forming the Pareto front. At a later stage, the same DP algorithm is used to generate fuel optimal vehicle speed and gear trajectories that are used as control signals for the haulers. Input to the DP algorithm is the distance to be travelled, road inclination, rolling resistance coefficient and a max speed limit to avoid unrealistic optimisation results.

    Thus, a method to describe the road and detect the road related data is needed to enable the optimisation. A map module is built utilising an extended Kalman Filter, Rauch-Tung-Striebel smoother and sensor fusion to merge data and estimate parameters not observable by sensors. The map module uses a model of the vehicle, sensor signals from a GPS or GNSS sensor and machine sensors to establish a map of the road.

    The wheel loader Pareto front is based on data developed in previous research combined with Volvo in-house data. The developed optimisation algorithms are implemented on a PC and in an interactive computer tablet based system. A human machine interface is created for the tablet, guiding the operators to follow the optimal control signals, which is speed for the haulers and cycle time for the loader. To evaluate the performance of the system it is tested in real working conditions.

    The contributions develop algorithms, set up a demo mission control system and carry out experiments. Altogether rendering in a platform that can be used as a base for a future design of an off-road transport mission control system.

    Delarbeid
    1. Road estimation and fuel optimal control of an off-road vehicle
    Åpne denne publikasjonen i ny fane eller vindu >>Road estimation and fuel optimal control of an off-road vehicle
    2017 (engelsk)Inngår i: Proceedings of the 3rd International Conference on Vehicle Technology and Intelligent Transport Systems, SciTePress, 2017, s. 58-67Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    SciTePress, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-142731 (URN)10.5220/0006247200580067 (DOI)978-989-758-242-4 (ISBN)
    Konferanse
    3rd International Conference on Vehicle Technology and Intelligent Transport Systems, VEHITS 2017, April 22-24, 2017, in Porto, Portugal
    Tilgjengelig fra: 2018-04-03 Laget: 2018-04-03 Sist oppdatert: 2018-11-22
    2. Fuel Optimal Control of an Articulated Hauler Utilising a Human Machine Interface
    Åpne denne publikasjonen i ny fane eller vindu >>Fuel Optimal Control of an Articulated Hauler Utilising a Human Machine Interface
    2019 (engelsk)Inngår i: Smart Cities, Green Technologies, and Intelligent Transport Systems / [ed] Donnellan, Brian; Klein, Cornel; Helfert, Markus; Gusikhin, Oleg; Pascoal, António, Springer International Publishing , 2019, s. 190-208Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Utilising optimal control presents an opportunity to increase the fuel efficiency in an off-road transport mission conducted by an articulated hauler. A human machine interface (HMI) instructing the hauler operator to follow the fuel optimal vehicle speed trajectory has been developed and tested in real working conditions. The HMI implementation includes a Dynamic Programming based method to calculate the optimal vehicle speed and gear shift trajectories. Input to the optimisation algorithm is road related data such as distance, road inclination and rolling resistance. The road related data is estimated in a map module utilising an Extended Kalman Filter (EKF), a Rauch-Tung-Striebel smoother and a data fusion algorithm. Two test modes were compared: (1) The hauler operator tried to follow the optimal vehicle speed trajectory as presented in the HMI and (2) the operator was given a constant target speed to follow. The objective of the second test mode is to achieve an approximately equal cycle time as for the optimally controlled transport mission, hence, with similar productivity. A small fuel efficiency improvement was found when the human machine interface was used.

    sted, utgiver, år, opplag, sider
    Springer International Publishing, 2019
    Serie
    Communications in Computer and Information Science book series (CCIS), ISSN 1865-0929, E-ISSN 1865-0937 ; 921
    Emneord
    Off-road, Construction equipment, Human machine interface, Optimal control, Dynamic programming, Kalman filters
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-153311 (URN)10.1007/978-3-030-02907-4_10 (DOI)978-3-030-02906-7 (ISBN)978-3-030-02907-4 (ISBN)
    Konferanse
    6th International Conference, SMARTGREENS 2017 and Third International Conference, VEHITS 2017, Porto, Portugal, April 22–24, 2017
    Tilgjengelig fra: 2018-12-12 Laget: 2018-12-12 Sist oppdatert: 2018-12-12
    3. Fuel optimal control of an off-road transport mission
    Åpne denne publikasjonen i ny fane eller vindu >>Fuel optimal control of an off-road transport mission
    2018 (engelsk)Inngår i: 2018 IEEE International Conference on Industrial Technology (ICIT), 2018, s. 175-180Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-151856 (URN)10.1109/ICIT.2018.8352172 (DOI)978-1-5090-5949-2 (ISBN)
    Konferanse
    2018 IEEE International Conference on Industrial Technology (ICIT), 19-22 Feb.,Lyon, France
    Tilgjengelig fra: 2018-10-06 Laget: 2018-10-06 Sist oppdatert: 2018-11-22
  • 106.
    Albrektsson, Jörgen
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Åslund, Jan
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Fuel optimal control of an off-road transport mission2018Inngår i: 2018 IEEE International Conference on Industrial Technology (ICIT), 2018, s. 175-180Konferansepaper (Fagfellevurdert)
  • 107.
    Albrektsson, Jörgen
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Åslund, Jan
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Road estimation and fuel optimal control of an off-road vehicle2017Inngår i: Proceedings of the 3rd International Conference on Vehicle Technology and Intelligent Transport Systems, SciTePress, 2017, s. 58-67Konferansepaper (Fagfellevurdert)
  • 108.
    Al-Egli, Fares
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System.
    Mohamed Moumin, Hassan
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System.
    Control, Design, and Implementation of Quasi Z-source Cascaded H-Bridge Inverter2018Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report is about control, design and implementation of a low voltage-fed quasi Z-source three-level inverter. The topology has been interesting for photovoltaic-systems due to its ability to boost the incoming voltage without needing an extra switching control. The topology was first simulated in Simulink and later implemented on a full-bridge module to measure the harmonic distortion and estimating the power losses of the inverter. An appropriate control scheme was used to set up a shootthrough and design a three-level inverter. The conclusion for the report is that the quasi Z-source inverter could boost the DC-link voltage in the simulation. But there should be more consideration to the internal resistance of the components for the implementation stage as it gave out a lower output voltage than expected. 

  • 109.
    Al-egli, Muntaher
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Zeidan Nasser, Adham
    Linköpings universitet, Institutionen för datavetenskap.
    Identifiering av anomalier i COSMIC genom analys av loggar2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Loggar är en viktig del av alla system, det ger en inblick i vad som sker. Att analysera loggar och extrahera väsentlig information är en av de största trenderna nu inom IT-branchen. Informationen i loggar är värdefulla resurser som kan användas för att upptäcka anomalier och hantera dessa innan det drabbar användaren.

    I detta examensarbete dyker vi in i grunderna för informationssökning och analysera undantagsutskrifter i loggar från COSMIC för att undersöka om det är möjligt att upptäcka anomalier med hjälp av retrospektivdata. Detta examensarbete ger även en inblick i möjligheten att visualisera data från loggar och erbjuda en kraftfull sökmotor. Därför kommer vi att fördjupa oss i de tre välkända program som adresserar frågorna i centraliserad loggning: Elasticsearch, Logstash och Kibana.

    Sammanfattningsvis visar resultatet att det är möjligt att upptäckta anomalier genom att tillämpa statistiska metoder både på retrospektiv- och realtidsdata.

  • 110.
    Alegret, Guillem
    et al.
    MAN Diesel & Turbo, Copenhagen, Denmark.
    Llamas, Xavier
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Vejlgaard-Laursen, Morten
    MAN Diesel & Turbo, Copenhagen, Denmark.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Modeling of a Large Marine Two-Stroke Diesel Engine with Cylinder Bypass Valve and EGR System2015Inngår i: 10th IFAC Conference on Manoeuvring and Control of Marine Craft MCMC 2015: Copenhagen, 24–26 August 2015 / [ed] Roberto Galeazzi and Mogens Blanke, IFAC Papers Online, 2015, Vol. 48, s. 273-278Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A nonlinear mean value engine model (MVEM) of a two-stroke turbocharged marine diesel engine is developed, parameterized and validated against measurement data. The goal is to have a computationally fast and accurate engine model that captures the main dynamics and can be used in the development of control systems for the newly introduced EGR system. The tuning procedure used is explained, and the result is a six-state MVEM with seven control inputs that capture the main system dynamics.

  • 111.
    Alene Asres, Georgies
    et al.
    University of Oulu, Finland.
    Dombovari, Aron
    University of Oulu, Finland.
    Sipola, Teemu
    University of Oulu, Finland.
    Puskas, Robert
    University of Szeged, Hungary.
    Kukovecz, Akos
    University of Szeged, Hungary; MTA SZTE Lendulet Porous Nanocomposites Research Grp, Hungary.
    Konya, Zoltan
    University of Szeged, Hungary; MTA SZTE React Kinet and Surface Chemistry Research Grp, Hungary.
    Popov, Alexey
    University of Oulu, Finland.
    Lin, Jhih-Fong
    University of Oulu, Finland.
    Lorite, Gabriela S.
    University of Oulu, Finland.
    Mohl, Melinda
    University of Oulu, Finland.
    Toth, Geza
    University of Oulu, Finland.
    Lloyd Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten. University of Oulu, Finland.
    Kordas, Krisztian
    University of Oulu, Finland.
    A novel WS2 nanowire-nanoflake hybrid material synthesized from WO3 nanowires in sulfur vapor2016Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, nr 25610Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, WS2 nanowire-nanoflake hybrids are synthesized by the sulfurization of hydrothermally grown WO3 nanowires. The influence of temperature on the formation of products is optimized to grow WS2 nanowires covered with nanoflakes. Current-voltage and resistance-temperature measurements carried out on random networks of the nanostructures show nonlinear characteristics and negative temperature coefficient of resistance indicating that the hybrids are of semiconducting nature. Bottom gated field effect transistor structures based on random networks of the hybrids show only minor modulation of the channel conductance upon applied gate voltage, which indicates poor electrical transport between the nanowires in the random films. On the other hand, the photo response of channel current holds promise for cost-efficient solution process fabrication of photodetector devices working in the visible spectral range.

  • 112.
    Alesand, Elias
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    Identification of Flying Drones in Mobile Networks using Machine Learning2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Drone usage is increasing, both in recreational use and in the industry. With it comes a number of problems to tackle. Primarily, there are certain areas in which flying drones pose a security threat, e.g., around airports or other no-fly zones. Other problems can appear when there are drones in mobile networks which can cause interference. Such interference comes from the fact that radio transmissions emitted from drones can travel more freely than those from regular UEs (User Equipment) on the ground since there are few obstructions in the air. Additionally, the data traffic sent from drones is often high volume in the form of video streams. The goal of this thesis is to identify so-called "rogue drones" connected to an LTE network. Rogue drones are flying drones that appear to be regular UEs in the network. Drone identification is a binary classification problem where UEs in a network are classified as either a drone or a regular UE and this thesis proposes machine learning methods that can be used to solve it. Classifications are based on radio measurements and statistics reported by UEs in the network. The data for the work in this thesis is gathered through simulations of a heterogenous LTE network in an urban scenario. The primary idea of this thesis is to use a type of cascading classifier, meaning that classifications are made in a series of stages with increasingly complex models where only a subset of examples are passed forward to subsequent stages. The motivation for such a structure is to minimize the computational requirements at the entity making the classifications while still being complex enough to achieve high accuracy. The models explored in this thesis are two-stage cascading classifiers using decision trees and ensemble learning techniques. It is found that close to 60% of the UEs in the dataset can be classified without errors in the first of the two stages. The rest is forwarded to a more complex model which requires more data from the UEs and can achieve up to 98% accuracy. 

  • 113.
    Alexandersson, Johan
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten.
    Nordin, Olle
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten.
    Implementation of CAN Communication Stack in AUTOSAR2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In the automotive industry today, embedded systems have reached a level of complexity which is not maintainable with the traditional approach of design- ing automotive embedded systems. For this purpose, many of the worlds leading automotive manufacturers have formed an alliance to apprehend this problem. This has resulted in AUTOSAR, an open standardized architecture for automotive embedded systems, which strives for increased flexibility and safety regulations. This thesis will explore the possibilities of implementing a CAN Communication stack using the AUTOSAR architecture and its corresponding methodology. As a result of this thesis, a complete AUTOSAR CAN communication stack has been implemented, as well has a simulator application with the purpose of testing its functionality. 

  • 114.
    Alexandersson, Johan
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorteknik.
    Nordin, Olle
    Linköpings universitet, Institutionen för systemteknik, Datorteknik.
    Implementation of SLAM Algorithms in a Small-Scale Vehicle Using Model-Based Development2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    As autonomous driving is rapidly becoming the next major challenge in the auto- motive industry, the problem of Simultaneous Localization And Mapping (SLAM) has never been more relevant than it is today. This thesis presents the idea of examining SLAM algorithms by implementing such an algorithm on a radio con- trolled car which has been fitted with sensors and microcontrollers. The software architecture of this small-scale vehicle is based on the Robot Operating System (ROS), an open-source framework designed to be used in robotic applications.

    This thesis covers Extended Kalman Filter (EKF)-based SLAM, FastSLAM, and GraphSLAM, examining these algorithms in both theoretical investigations, simulations, and real-world experiments. The method used in this thesis is model- based development, meaning that a model of the vehicle is first implemented in order to be able to perform simulations using each algorithm. A decision of which algorithm to be implemented on the physical vehicle is then made backed up by these simulation results, as well as a theoretical investigation of each algorithm.

    This thesis has resulted in a dynamic model of a small-scale vehicle which can be used for simulation of any ROS-compliant SLAM-algorithm, and this model has been simulated extensively in order to provide empirical evidence to define which SLAM algorithm is most suitable for this application. Out of the algo- rithms examined, FastSLAM was proven to the best candidate, and was in the final stage, through usage of the ROS package gMapping, successfully imple- mented on the small-scale vehicle.

  • 115.
    Alfredsson, Jon
    Linköpings universitet, Institutionen för systemteknik.
    Design of a parallel A/D converter system on PCB: For high-speed sampling and timing error correction2002Independent thesis Basic level (professional degree)Oppgave
    Abstract [en]

    The goals for most of today’s receiver system are sampling at high-speed, with high resolution and with as few errors as possible. This master thesis describes the design of a high-speed sampling system with"state-of-the-art"components available on the market. The system is designed with a parallel Analog-to-digital converter (ADC) architecture, also called time interleaving. It aims to increase the sampling speed of the system. The system described in this report uses four 12-bits ADCs in parallel. Each ADC can sample at 125 MHz and the total sampling speed will then theoretically become 500 Ms/s. The system has been implemented and manufactured on a printed circuit board (PCB). Up to four boards can be connected in parallel to get 2 Gs/s theoretically.

    In an approach to increase the systems performance even further, a timing error estimation algorithm will be used on the sampled data. This algorithm estimates the timing errors that occur when sampling with non-uniform time interval between samples. After the estimations, the sampling clocks can be adjusted to correct the errors.

    This thesis is concerning some ADC theory, system design and PCB implementation. It also describes how to test and measure the system’s performance. No measurement results are presented in this thesis because measurements will be done after this project. The last part of the thesis discusses future improvementsto achieve even higher performance.

  • 116.
    Alfredsson, Sandra
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Model Based Diagnosis of an Air Source Heat Pump2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of a heat pump is to control the temperature of an enclosed space. This is done by using heat exchange with a heat source, for example water, air, or ground. In the air source heat pump that has been studied during this master thesis, a refrigerant exchanges heat with the outdoor air and with a water distribution system.

    The heat pump is controlled through the circuit containing the refrigerant and it is therefore crucial that this circuit is functional. To ensure this, a diagnosis system has been created, to be able to detect and isolate sensor errors. The diagnosis system is based on mathematical models of the refrigerant circuit with its main components: a compressor, an expansion valve, a plate heat exchanger, an air heat exchanger, and a four-way valve. Data has been collected from temperature- and pressure sensors on an air source heat pump. The data has then been divided into data for model estimation and data for model validation. The models are used to create test quantities, which in turn are used by a diagnosis algorithm to determine whether an error has occurred or not.

    There are nine temperature sensors and two pressure sensors on the studied air source heat pump. Four fault modes have been investigated for each sensor: Stuck, Offset, Short circuit and Open circuit. The designed diagnosis system is able to detect all of the investigated error modes and isolate 40 out of 44 single errors. However, there is room for improvement by constructing more test quantities to detect errors and decouple more fault modes. To further develop the diagnosis system, the existing models can be improved and new models can be created.

  • 117.
    Alhowaidi, Mohammad
    Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Tekniska högskolan.
    Real-Time Systems with Radiation-Hardened Processors: A GPU-based Framework to Explore Tradeoffs2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Radiation-hardened processors are designed to be resilient against soft errorsbut such processors are slower than Commercial Off-The-Shelf (COTS)processors as well significantly costlier. In order to mitigate the high costs,software techniques such as task re-executions must be deployed together withadequately hardened processors to provide reliability. This leads to a huge designspace comprising of the hardening level of the processors and the numberof re-executions of each task in the system. Each configuration in this designspace represents a tradeoff between processor load, reliability and costs.

    The reliability comes at the price of higher costs due to higher levels of hardeningand performance degradation due to hardening or due to re-executions.Thus, the tradeoffs between performance, reliability and costs must be carefullystudied. Pertinent questions that arise in such a design scenario are — (i)how many times a task must be re-executed and (ii) what should be hardeninglevel? — such that the system reliability is satisfied.

    In order to evaluate such tradeoffs efficiently, in this thesis, we proposenovel framework that harnesses the computational power of Graphics ProcessingUnits (GPUs). Our framework is based on a system failure probabilityanalysis that connects the probability of failure of tasks to the overall systemreliability. Based on characteristics of this probabilistic analysis as well asreal-time deadlines, we derive bounds on the design space to prune infeasiblesolutions. Finally, we illustrate the benefits of our proposed framework withseveral experiments

  • 118.
    Ali, A.
    et al.
    Riphah Int University, Pakistan.
    Israr-Qadir, Muhammad
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Wazir, Z.
    Riphah Int University, Pakistan.
    Tufail, M.
    Riphah Int University, Pakistan.
    Ibupoto, Zafar Hussain
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Jamil-Rana, Sadaf
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Lasers and Optron, Pakistan.
    Khan, S. A.
    National Centre Phys, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor2015Inngår i: Indian Journal of Physics, ISSN 0973-1458, E-ISSN 0974-9845, Vol. 89, nr 4, s. 331-336Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 mu m is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 x 10(-4) and 8 x 10(-2) M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of similar to 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of similar to 12 s.

  • 119.
    Ali Abdul-Amir, Ahmed
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik.
    Att lösa reglertekniska problem med Modelica2008Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Modelica is a multi-domain and equation-based modeling language. Modelica is based on object-oriented principles and non-causal modeling. The language is constructed to facilitate reuse and decompose models. The models and the modellibrary can modified to design a new nonlinear components.

    Object-oriented modeling is an excellent way to analyze and study large complex heterogeneous physical systems. The object-oriented modeling approach build on reusing and decomposition of models and non-causal modeling.

    Modeling physical systems often leads to a DAE system with index 2 or 3. It is required to use automated symbolic manipulation of the DAE system to do the simulation.

    Modelica need a compiler tool to run the simulation. Dymola is the dominating tool on the market. Through a graphic editor the user can easily model and simulate the physical system.

  • 120.
    Ali, Ahmed
    Linköpings universitet, Institutionen för systemteknik.
    A study of security in wireless and mobile payments2010Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Mobile payments are increasing in popularity in recent years. New mobile solutions are being developed in the form of new Internet capable mobile devices such as the IPhone and new wireless networks such as the LTE and WiMAX networks.

    This report will present, explain and compare some of the most popular wireless networks that enable mobile payments, from a security point of view. The chosen networks are 3G with connection to GSM, and WLAN networks. The main security mechanisms involved in each network, and how they work will be studied. Security requirements and some of the most important threats each network faces will be presented and discussed. The main purpose of the report is to examine if mobile payments offer an acceptable level of security to the average user.

  • 121.
    Ali, Akbar
    et al.
    Riphah Int University, Pakistan.
    Fakhar-E-Alam, Muhammad
    GC University, Pakistan.
    Abbas, Najeeb
    GC University, Pakistan.
    Wazir, Zafar
    Riphah Int University, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Tufail, Muhammad
    Riphah Int University, Pakistan.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Laser and Optron, Pakistan.
    Silver-chitosan nanobiocomposite as urea biosensor2014Inngår i: Optoelectronics and Advanced Materials Rapid Communications, ISSN 1842-6573, E-ISSN 2065-3824, Vol. 8, nr 11-12, s. 1238-1242Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silver nanoparticles (Ag NPs) were synthesized by aqueous chemical growth technique. The above mentioned synthesized materials were characterized by applying scanning electron microscope (SEM) and X-ray diffraction for confirmation of morphological analysis, compositional purity, and crystalline property and emission characteristics as well. In order to fabricate the urea biosensor (potentiometric), a solution of deionized water and chitosan was prepared having Ag NPs. The said solution was dropped on the glass fiber filter having diameter of 2 cm. A wire of copper having thickness of approximately 500 pm was used for the voltage signal to pull out from the said working nanoparticles (NPs). To improve the strength, sensitivity and the quality of the potentiometric urea biosensor, a specific functional surface of Ag NPs was attained by electrostatic restrained of an enzyme (urease) onto the chitosan-Ag (a nanobiocomposite). The potentiometric reaction was measured via electrochemical detection technique. The potentiometric urea biosensor illustrates significant sensibility at room temperature with approximate to 42 mV as per span. Furthermore, the said biosensor showed an appropriate stable response within 7 sec.

  • 122.
    Ali, Akhtar
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Dastgeer, Usman
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Kessler, Christoph
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    OpenCL for programming shared memory multicore CPUs2011Inngår i: Fourth Swedish Workshop on Multi-Core Computing MCC-2011: November 23-25, 2011, Linköping University, Linköping, Sweden / [ed] Christoph Kessler, Linköping: Linköping University , 2011, Vol. S. 65-70, s. 65-70Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this work, we evaluate the effectiveness of OpenCL for programming multicore CPUs in a comparative case study with OpenMP and Intel TBB for five benchmark applications: matrix multiply, LU decomposition, 2D image convolution, Pi value approximation and image histogram generation.

  • 123.
    Ali, Rahman
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Design of Building Blocks in Digital Baseband Transceivers for Body-Coupled Communication2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Advances in communication technologies continue to increase information sharing among the people.~Short-range wireless networking technologies such as Bluetooth or ZigBee, which are mainly used for data transfer over short range, will, however, suffer from network congestion, high power consumption and security issues in the future.

    The body-coupled communication (BCC), a futuristic short-range wireless technology, uses the human body as a transmission medium. In BBC channel, a small electric field is induced onto the human body which enables the propagation of a signal between communication devices that are in the proximity or direct contact with the human body. The direct baseband transmission and simple architecture make BCC an attractive candidate for a future short-range wireless communication technology in particular applications such as body area network.

    The main focus of this thesis is on the design and implementation of digital baseband transmitter and receiver for the body-coupled communication. The physical layer (PHY) implementation of the digital baseband transmitter and receiver is inspired from the IEEE 802.3 Ethernet transmission protocol. The digital design is implemented at RTL level using hardware description language (VHDL). The functionality of the digital baseband transmitter and receiver is demonstrated by developing data transfer application layers.

  • 124.
    Ali Shah, Syed Asmat
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Qazi, Sohaib Ayaz
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Design of an all-digital, reconfigurable sigma-deltamodulator2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis presents a model of reconfigurable sigma-delta modulator. These modulators areintended for high speed digital Digital to Analog Converters. The modulators are intendedto reduce complexity of current steering DACs and also considered as a front end of dataconverters. Quantization noise present in digital signal is pushed to higher frequencies bysigma-delta modulators. Noise in high band frequencies can be removed by a low pass filter.

    A test methodology involving generation of baseband signal, interpolation and digitizationis opted. Topologies tested in MATLAB® include signal feedback and error feedback modelsof first-order and second-order sigma-delta modulators. Error feedback and signal feedbackfirst-order modulators’ performance is quite similar. The SNR of a first-order error feedbackmodel is 52.3 dB and 55.9 dB for 1 and 2 quantization bits, respectively. In second-orderSDM, signal feedback provides best performance with 80 dB SNR.

    The other part of the thesis focuses on the implementation of the sigma-delta modulator(SDM) using faster time to market approach. SoC Encounter, a tool from Cadence, is theeasiest way to do this job. The modulators are implemented in 65-nm technology. The reconfigurablesigma-delta modulator is designed using Verilog-HDL language. Switches areintroduced to control the reconfigurable SDM for different input word lengths. Word-lengthcan vary from 0 to 4 bits. Modulator is designed to work for frequencies of 2 GHz. To netlistthe design, Design Compiler is used which is a tool from Synopsys®.

    The area of the chip reported by design compiler is 563.68 um. When the design is implementedin SoC Encounter, area of the chip is increased, because the core utilization, whiledesigning, is only 60%, which is 556.8 um. Remaining 40% area is used by buffers, inverterand filler cells during clock tree synthesis. The buffers and inverters are added to removethe clock phase delay between different registers. Power consumption of the chip is 319mW.Internal power of the modulators is 219.1 mW. Switching power of output capacitances is99.9 mW, which is 31% of the total power consumed. Main concern of the power loss isconsidered to be power leakage. To reduce the leakage power and achieve high speed designCORE65GPHVT libraries are used. Leakage power of the design is 2.825 uW which is0.00088% of the total power.

  • 125.
    Ali Soomro, Razium
    et al.
    University of Sindh, Pakistan.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Sirajuddin,
    University of Sindh, Pakistan.
    Ishaq Abro, Muhammad
    Mehran University of Engineering & Technology, Pakistan .
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Controlled synthesis and electrochemical application of skein-shaped NiO nanostructures2015Inngår i: Journal of Solid State Electrochemistry, ISSN 1432-8488, E-ISSN 1433-0768, Vol. 19, nr 3, s. 913-922Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A simple, economical and mild solution chemistry method was used to synthesize diverse nickel oxide (NiO) nanostructures employing methionine as a growth-directing agent. The as-synthesized NiO nanostructures were observed to possess a unique skein-shape morphology with uniform spherical distribution. The NiO nanoskein (NiO NSk) formation was extensively studied using X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) techniques, respectively. The unique NiO NSks exhibited better electrocatalytic activity towards glucose oxidation in alkaline media, enabling the development of a highly sensitive non-enzymatic glucose sensor. The observed analytical properties included high sensitivity (1915 mu A mM(-1) cm(-2)), wide linear range (0.1-5.0 mM), low detection limit (0.7 mu M), higher stability and reproducibility. Moreover, the sensor is selective in the presence of interfering species such as ascorbic acid (AA), uric acid (UA) and dopamine (DP) during the non-enzymatic glucose sensing. The worthy-of-notice electrocatalytic activity and economical feasible preparation of NiO NSk-shaped electroactive material for direct glucose-sensing applications make the present study of high interest for the fabrication of low-cost devices. A NiO NSk-based glucose sensor has also been employed for glucose determination in human serum with adequate results, suggesting high potential for the routine monitoring of glucose from biotechnology, clinical and food industry samples.

  • 126.
    Ali Soomro, Razium
    et al.
    University of Bristol, England; University of Sindh, Pakistan.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Tufail Hussain Sirajuddin; Sherazi, Syed
    Univ Sindh, Natl Ctr Excellence Analyt Chem, Jamshoro 76080, Pakistan.
    Ishaq Abro, Muhammad
    Mehran University of Engn and Technology, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Ahmed Mahesar, Sarfaraz
    University of Sindh, Pakistan.
    Hussain Kalwar, Nazar
    University of Sindh, Pakistan.
    Glycine-assisted preparation of Co3O4 nanoflakes with enhanced performance for non-enzymatic glucose sensing2015Inngår i: MATERIALS EXPRESS, ISSN 2158-5849, Vol. 5, nr 5, s. 437-444Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study a simple, inexpensive and efficient route is proposed to synthesise attractive cobalt oxide (Co3O4) nanostructures using glycine as an effective growth controller and regulator. The as-synthesised Co3O4 nanostructures were observed to possess unique nanoflake shape morphological features with highly dense distribution. The formation of Co3O4 nanoflakes (Co3O4 NFKs) was elaborately explored using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Scanning electron microscopy (SEM) respectively. The unique Co3O4 nanoflakes were known to possess excellent electro-catalytic potential for the oxidation of glucose in alkaline medium. This potential property allowed successful development of highly sensitive (1180 mu A mM(-1) cm(-2)), selective and stable non-enzymatic glucose sensor. In addition, the developed sensor had a wide working range (0.1-5.0 mM), low limit of detection (0.7 mu M), and excellent reproducibility, besides the capability of analysing real blood glucose samples.

  • 127.
    Ali Soomro, Razium
    et al.
    University of Sindh, Pakistan; University of Bristol, England.
    Nafady, Aynam
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Tufail Hussain Sirajuddin; Sherazi, Syed
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Ishaq Abro, Muhammad
    Mehran University of Engn and Technology, Pakistan.
    Development of sensitive non-enzymatic glucose sensor using complex nanostructures of cobalt oxide2015Inngår i: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 34, s. 373-381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study reports the synthesis of cobalt oxide (Co3O4) nanostructures and their application in enzyme free electrochemical sensing of glucose. The synthesized nanostructures were elaborately characterized via number of analytical techniques including scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The as-synthesized nanostructures of Co3O4 were found to exhibited nanodisc like morphology with the size dimension in range of 300-500 nm. The obtained morphological features were evaluated for their electrochemical potential towards oxidation of glucose which enabled development of sensitive (27.33 mu A mM(-1) cm(-2)), and stable enzyme free glucose sensor. In addition, the developed sensor showed excellent linearity (r(2)=0.9995), wide detection range (0.5-5.0 mM), lower detection limit (0.8 mu M) and extreme selectivity towards glucose in the presence of common interferents like dopamine (DP), ascorbic acid (AA) and uric acid (UA). The successfully application of developed sensor for real blood glucose analysis further reflects its capability for routine glucose measurement.

  • 128.
    Ali Soomro, Razium
    et al.
    University of Bristol, England; University of Sindh, Pakistan.
    Richard Hallam, Keith
    University of Bristol, England.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Tufail Hussain Sherazi, Syed
    University of Sindh, Pakistan.
    Sanam Sirajjuddin; Memon, Safia
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Amino acid assisted growth of CuO nanostructures and their potential application in electrochemical sensing of organophosphate pesticide2016Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 190, s. 972-979Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work reports a highly sensitive electrochemical sensor for organophosphate pesticide (malathion) based on unique and attractive CuO nanostructures. The discussed nanostructures were synthesized using low temperature hydrothermal growth method utilizing green amino acids such as glycine, serine, threonine and histidine as effective bio-compatible templates. The morphological evaluation demonstrated formation of unique and attractive 1-D nanostructures reflecting the effective growth controlling and directing capabilities of the utilized amino acids. The as-synthesized CuO nanostructures were noted to possess high affinity towards malathion which enabled their application as electrode material for the development of affinity based electrochemical sensor. Although, the as-synthesized morphologies were all sensitive towards malathion but the glycine directed triangular flake-like nanostructures exhibited greater sensitivity compared to other competitors. The electrochemical behaviour of the modified electrodes was studied using cyclic voltammetry (CV) whereas, differential pulse voltammetry (DPV) was utilized for the analytical evaluation of the sensor. The developed sensor demonstrated high reproducibility, stability, wide detection window (1-12 nM), and sensitivity to detect malathion up to 0.1 nM based on suppressive signal measurement. In addition, the sensor system exhibited high anti-interference capability in the presence of common co-existing pesticides like lindane, carbendazim, and trichlorfon. The developed sensor provides an effective measure for detecting extremely low concentration of malathion with wide applicability in various fields. (C) 2015 Elsevier Ltd. All rights reserved.

  • 129.
    Ali, Syed M. Usman
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fabrication and characterization of ZnO nanostructures for sensing and photonic device applications2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Nanotechnology is an emerging inter-disciplinary paradigm which encompasses diverse fields of science and engineering converge at the nanoscale. This nanoscale science and nanostructure engineering have well demonstrated in the fabrication of sensors/transducers devices with faster response time and better sensitivity then the planer version of the sensor’s configurations. Nanotechnology is not just to grow/fabricate nanostructures by just mixing nanoscale materials together but it requires the ability to understand and to precisely manipulate and control of the developed nanomaterials in a useful way. Nanotechnology is aiding to substantially improve, even revolutionize, many technology and industry sectors like information technology, energy, environmental science, medicine/medical instrumentation, homeland security, food safety, and transportation, among many others. Such applications of nanotechnology are delivering in both expected and unexpected ways on nanotechnology’s promise to benefit the society.

    The semiconductor ZnO with wide band gap (~ 3.37 eV) is a distinguish and unique material and its nanostructures have attracted great attention among the researchers due to its peculiar properties such as large exciton binding energy (60 meV) at room temperature, the high electron mobility, high thermal conductivity, good transparency and easiness of fabricating it in the different type of nanostructures. Based on all these fascinating properties, ZnO have been chosen as a suitable material for the fabrication of photonic, transducers/sensors, piezoelectric, transparent and spin electronics devices etc. The objective of the current study is to highlight the recent developments in materials and techniques for electrochemical sensing and hetrostructure light emitting diodes (LEDs) luminescence properties based on the different ZnO nanostructures. The sensor devices fabricated and characterized in the work were applied to determine and monitor the real changes of the chemical or biochemical species. We have successfully demonstrated the application of our fabricated devices as primary transducers/sensors for the determination of extracellular glucose and the glucose inside the human fat cells and frog cells using the potentiometric technique. Moreover, the fabricated ZnO based nanosensors have also been applied for the selective determination of uric acid, urea and metal ions successfully. This thesis relates specifically to zinc oxide nanostructure based electrochemical sensors and photonic device (LED) applications.

    Delarbeid
    1. A fast and sensitive potentiometric glucose microsensor based on glucose oxidase coated ZnO nanowires grown on a thin silver wire
    Åpne denne publikasjonen i ny fane eller vindu >>A fast and sensitive potentiometric glucose microsensor based on glucose oxidase coated ZnO nanowires grown on a thin silver wire
    2010 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 145, nr 2, s. 869-874Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this study, a potentiometric glucose biosensor was fabricated by immobilization of glucose oxidase on to zinc oxide nanowires. Zinc oxide nanowires with 250-300 nm diameters and approximately 1.2 mu m lengths were grown on the surface of silver wires with a diameter of 250 mu m. Glucose oxidase (GOD) was electrostatically immobilized on the surface of the well aligned zinc oxide nanowires resulting in sensitive, selective, stable and reproducible glucose biosensors. The potentiometric response vs. Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (0.5-1000 mu M) suitable for intracellular glucose detection. By applying a membrane on the sensor the linear range could be extended to 0.5 mu M to 10 mM, which increased the response time from less than 1 to 4s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents with glucose sensing such as uric acid and ascorbic acid.

    sted, utgiver, år, opplag, sider
    Elsevier Science B.V., Amsterdam., 2010
    Emneord
    Glucose oxidase (GOD), Nafion membrane, Potentiometric biosensor, Electrochemical nanodevices, ZnO nanowires, Fast response
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-55508 (URN)10.1016/j.snb.2009.12.072 (DOI)000276589900039 ()
    Tilgjengelig fra: 2010-04-30 Laget: 2010-04-30 Sist oppdatert: 2017-12-12bibliografisk kontrollert
    2. Glocuse detection with a commercial MOSFET using ZnO nanowires extended gate
    Åpne denne publikasjonen i ny fane eller vindu >>Glocuse detection with a commercial MOSFET using ZnO nanowires extended gate
    2009 (engelsk)Inngår i: IEEE Transaction on Nanotechnology, Vol. 8, nr 6, s. 678-683Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Zinc oxide (ZnO) nanowires were grown on a silver (Ag) wire with a diameter of approximately 250 $mu$m and used in an electrochemical sensor. The enzyme glucose oxidase (GOD) was immobilized on the ZnO nanowires and the silver wire was connected directly to the gate of a MOSFET. Upon exposure to glucose (1-100 $mu$M) the electrochemical response from the glucose oxidase induced a stable measurable voltage change on the gate leading to a strong modulation of the current through the MOSFET. For a sensor with uniform ZnO nanowires functionalized with GOD a fast response time of less than 100 ms, was demonstrated. The effect of the uniformity of the ZnO nanowires on the sensing property was also investigated. The extended gate arrangement facilitated glucose detection in small sample volumes and made it possible to demonstrate the present sensor concept using a standard low threshold MOSFET. The extended gate MOSFET sensor approach demonstrates the possibility and potential of the use of nano-structures coupled to standard electronic components for biosensing applications.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-50566 (URN)10.1109/TNANO.2009.2019958 (DOI)
    Merknad
    ©2009 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. Syed M. Usman Ali, Omer Nour, Magnus Willander and Bengt Danielsson, Glocuse detection with a commercial MOSFET using ZnO nanowires extended gate, 2009, IEEE Transaction on Nanotechnology, (8), 6, 678-683. http://dx.doi.org/10.1109/TNANO.2009.2019958 Tilgjengelig fra: 2009-10-12 Laget: 2009-10-12 Sist oppdatert: 2014-01-15
    3. Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose
    Åpne denne publikasjonen i ny fane eller vindu >>Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose
    Vise andre…
    2010 (engelsk)Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 25, nr 10, s. 2205-2211Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this article, we report a functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose. To adjust the sensor for intracellular glucose measurements, we grew hexagonal ZnO nanorods on the tip of a silver-covered borosilicate glass capillary (0.7 mu m diameter) and coated them with the enzyme glucose oxidase. The enzyme-coated ZnO nanorods exhibited a glucose-dependent electrochemical potential difference versus an Ag/AgCl reference microelectrode. The potential difference was linear over the concentration range of interest (0.5-1000 mu M). The measured glucose concentration in human adipocytes or frog oocytes using our ZnO-nanorod sensor was consistent with values of glucose concentration reported in the literature; furthermore, the sensor was able to show that insulin increased the intracellular glucose concentration. This nanoelectrode device demonstrates a simple technique to measure intracellular glucose concentration.

    sted, utgiver, år, opplag, sider
    Elsevier Science B.V., Amsterdam., 2010
    Emneord
    ZnO nanorods; Functionalisation; Intracellular glucose; Electrochemical sensor
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-58381 (URN)10.1016/j.bios.2010.02.025 (DOI)000278702600004 ()
    Merknad
    Original Publication: Muhammad Asif, Syed Usman Ali, Omer Nour, Magnus Willander, Cecilia Brännmark, Peter Strålfors, Ulrika Englund, Fredrik Elinder and Bengt Danielsson, Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose, 2010, Biosensors & bioelectronics, (25), 10, 2205-2211. http://dx.doi.org/10.1016/j.bios.2010.02.025 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Tilgjengelig fra: 2010-08-13 Laget: 2010-08-11 Sist oppdatert: 2018-01-25
    4. Wireless Remote Monitoring of Glucose Using a Functionalized ZnO Nanowire Arrays Based Sensor
    Åpne denne publikasjonen i ny fane eller vindu >>Wireless Remote Monitoring of Glucose Using a Functionalized ZnO Nanowire Arrays Based Sensor
    Vise andre…
    2011 (engelsk)Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 11, nr 9, s. 8485-8496Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents a prototype wireless remote glucose monitoring system interfaced with a ZnO nanowire arrays-based glucose sensor, glucose oxidase enzyme immobilized onto ZnO nanowires in conjunction with a Nafion (R) membrane coating, which can be effectively applied for the monitoring of glucose levels in diabetics. Global System for Mobile Communications (GSM) services like General Packet Radio Service (GPRS) and Short Message Service (SMS) have been proven to be logical and cost effective methods for gathering data from remote locations. A communication protocol that facilitates remote data collection using SMS has been utilized for monitoring a patients sugar levels. In this study, we demonstrate the remote monitoring of the glucose levels with existing GPRS/GSM network infra-structures using our proposed functionalized ZnO nanowire arrays sensors integrated with standard readily available mobile phones. The data can be used for centralized monitoring and other purposes. Such applications can reduce health care costs and allow caregivers to monitor and support to their patients remotely, especially those located in rural areas.

    sted, utgiver, år, opplag, sider
    MDPI, 2011
    Emneord
    electrochemical nanosensor, ZnO nanowires, glucose oxidase, Nafion (R) membrane, remote monitoring, data acquisition, Global System for Mobile Communications (GSM)
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-71798 (URN)10.3390/s110908485 (DOI)000295211700017 ()
    Tilgjengelig fra: 2011-11-04 Laget: 2011-11-04 Sist oppdatert: 2017-12-08
    5. Selective potentiometric determination of uric acid with uricase immobilized on ZnO nanowires
    Åpne denne publikasjonen i ny fane eller vindu >>Selective potentiometric determination of uric acid with uricase immobilized on ZnO nanowires
    Vise andre…
    2011 (engelsk)Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 152, nr 2, s. 241-247Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this study, a potentiometric uric acid biosensor was fabricated by immobilization of uricase onto zinc oxide (ZnO) nanowires. Zinc oxide nanowires with 80-150 nm in diameter and 900 nm to 1.5 mu m in lengths were grown on the surface of a gold coated flexible plastic substrate. Uricase was electrostatically immobilized on the surface of well aligned ZnO nanowires resulting in a sensitive, selective, stable and reproducible uric acid biosensor. The potentiometric response of the ZnO sensor vs Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (1-650 mu M) suitable for human blood serum. By applying a Nafion (R) membrane on the sensor the linear range could be extended to 1-1000 mu M at the expense of an increased response time from 6.25 s to less than 9 s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.

    sted, utgiver, år, opplag, sider
    Elsevier Science B.V., Amsterdam., 2011
    Emneord
    ZnO nanowires, Potentiometric nanosensor, Uricase, Uric acid, Nafion (R), Membrane, Electrochemical nanodevices
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-67542 (URN)10.1016/j.snb.2010.12.015 (DOI)000288877700015 ()
    Merknad
    Original Publication: Syed Usman Ali, Naveed Ul Hassan Alvi, Zafar Hussain Ibupoto, Omer Nur, Magnus Willander and Bengt Danielsson, Selective potentiometric determination of uric acid with uricase immobilized on ZnO nanowires, 2011, SENSORS AND ACTUATORS B-CHEMICAL, (152), 2, 241-247. http://dx.doi.org/10.1016/j.snb.2010.12.015 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Tilgjengelig fra: 2011-04-18 Laget: 2011-04-18 Sist oppdatert: 2017-12-11bibliografisk kontrollert
    6. Fabrication and comparative optical characterization of n-ZnO nanostructures (nanowalls, nanorods, nanoflowers and nanotubes)/p-GaN white-light-emitting diodes
    Åpne denne publikasjonen i ny fane eller vindu >>Fabrication and comparative optical characterization of n-ZnO nanostructures (nanowalls, nanorods, nanoflowers and nanotubes)/p-GaN white-light-emitting diodes
    Vise andre…
    2011 (engelsk)Inngår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 64, nr 8, s. 697-700Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    White light-emitting diodes (LED) based on ZnO (nanowalls, nanorods, nanoflowers and nanotubes)/p-GaN were fabricated and their electrical, optical and electro-optical characteristics were comparatively characterized. All the LED showed rectifying behavior. The nanowalls and nanorods structures have the highest photoluminescence emission intensity in the visible and UV (at 3.29 eV) regions, respectively. The nanowalls have the highest color rendering index, with a value of 95, and the highest electroluminescence intensity with peaks approximately centered at 420, 450 nm and broad peak covering the visible region.

    sted, utgiver, år, opplag, sider
    Elsevier Science B.V., Amsterdam., 2011
    Emneord
    Zinc oxide, Nanostructure, Aqueous chemical growth, Optical properties, Heterojunctions
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-66849 (URN)10.1016/j.scriptamat.2010.11.046 (DOI)000287908300002 ()
    Tilgjengelig fra: 2011-03-22 Laget: 2011-03-21 Sist oppdatert: 2017-12-11bibliografisk kontrollert
  • 130.
    Alickovic, Emina
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Kevric, Jasmin
    Int Burch University, Bosnia and Herceg.
    Subasi, Abdulhamit
    Effat University, Saudi Arabia.
    Performance evaluation of empirical mode decomposition, discrete wavelet transform, and wavelet packed decomposition for automated epileptic seizure detection and prediction2018Inngår i: Biomedical Signal Processing and Control, ISSN 1746-8094, E-ISSN 1746-8108, Vol. 39, s. 94-102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study proposes a new model which is fully specified for automated seizure onset detection and seizure onset prediction based on electroencephalography (EEG) measurements. We processed two archetypal EEG databases, Freiburg (intracranial EEG) and CHB-MIT (scalp EEG), to find if our model could outperform the state-of-the art models. Four key components define our model: (1) multiscale principal component analysis for EEG de-noising, (2) EEG signal decomposition using either empirical mode decomposition, discrete wavelet transform or wavelet packet decomposition, (3) statistical measures to extract relevant features, (4) machine learning algorithms. Our model achieved overall accuracy of 100% in ictal vs. inter-ictal EEG for both databases. In seizure onset prediction, it could discriminate between inter-ictal, pre-ictal, and ictal EEG with the accuracy of 99.77%, and between inter-ictal and pre-ictal EEG states with the accuracy of 99.70%. The proposed model is general and should prove applicable to other classification tasks including detection and prediction regarding bio-signals such as EMG and ECG. (C) 2017 Elsevier Ltd. All rights reserved.

  • 131.
    Alickovic, Emina
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Lunner, Thomas
    Linköpings universitet, Institutet för handikappvetenskap (IHV). Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten. Eriksholm Research Centre, Oticon A/S, 20 Rortangvej, Snekkersten, Denmark.
    Gustafsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    A System Identification Approach to Determining Listening Attention from EEG Signals2016Inngår i: 2016 24TH EUROPEAN SIGNAL PROCESSING CONFERENCE (EUSIPCO), IEEE , 2016, s. 31-35Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We still have very little knowledge about how ourbrains decouple different sound sources, which is known assolving the cocktail party problem. Several approaches; includingERP, time-frequency analysis and, more recently, regression andstimulus reconstruction approaches; have been suggested forsolving this problem. In this work, we study the problem ofcorrelating of EEG signals to different sets of sound sources withthe goal of identifying the single source to which the listener isattending. Here, we propose a method for finding the number ofparameters needed in a regression model to avoid overlearning,which is necessary for determining the attended sound sourcewith high confidence in order to solve the cocktail party problem.

  • 132.
    Alickovic, Emina
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Subasi, Abdulhamit
    Effat Univ, Saudi Arabia.
    Ensemble SVM Method for Automatic Sleep Stage Classification2018Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 67, nr 6, s. 1258-1265Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sleep scoring is used as a diagnostic technique in the diagnosis and treatment of sleep disorders. Automated sleep scoring is crucial, since the large volume of data should be analyzed visually by the sleep specialists which is burdensome, time-consuming tedious, subjective, and error prone. Therefore, automated sleep stage classification is a crucial step in sleep research and sleep disorder diagnosis. In this paper, a robust system, consisting of three modules, is proposed for automated classification of sleep stages from the single-channel electroencephalogram (EEG). In the first module, signals taken from Pz-Oz electrode were denoised using multiscale principal component analysis. In the second module, the most informative features are extracted using discrete wavelet transform (DWT), and then, statistical values of DWT subbands are calculated. In the third module, extracted features were fed into an ensemble classifier, which can be called as rotational support vector machine (RotSVM). The proposed classifier combines advantages of the principal component analysis and SVM to improve classification performances of the traditional SVM. The sensitivity and accuracy values across all subjects were 84.46% and 91.1%, respectively, for the five-stage sleep classification with Cohens kappa coefficient of 0.88. Obtained classification performance results indicate that, it is possible to have an efficient sleep monitoring system with a single-channel EEG, and can be used effectively in medical and home-care applications.

  • 133.
    Alickovic, Emina
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Subasi, Abdulhamit
    Effat University, Saudi Arabia.
    Medical Decision Support System for Diagnosis of Heart Arrhythmia using DWT and Random Forests Classifier2016Inngår i: Journal of medical systems, ISSN 0148-5598, E-ISSN 1573-689X, Vol. 40, nr 4, s. 108-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, Random Forests (RF) classifier is proposed for ECG heartbeat signal classification in diagnosis of heart arrhythmia. Discrete wavelet transform (DWT) is used to decompose ECG signals into different successive frequency bands. A set of different statistical features were extracted from the obtained frequency bands to denote the distribution of wavelet coefficients. This study shows that RF classifier achieves superior performances compared to other decision tree methods using 10-fold cross-validation for the ECG datasets and the obtained results suggest that further significant improvements in terms of classification accuracy can be accomplished by the proposed classification system. Accurate ECG signal classification is the major requirement for detection of all arrhythmia types. Performances of the proposed system have been evaluated on two different databases, namely MIT-BIH database and St. -Petersburg Institute of Cardiological Technics 12-lead Arrhythmia Database. For MIT-BIH database, RF classifier yielded an overall accuracy 99.33 % against 98.44 and 98.67 % for the C4.5 and CART classifiers, respectively. For St. -Petersburg Institute of Cardiological Technics 12-lead Arrhythmia Database, RF classifier yielded an overall accuracy 99.95 % against 99.80 % for both C4.5 and CART classifiers, respectively. The combined model with multiscale principal component analysis (MSPCA) de-noising, discrete wavelet transform (DWT) and RF classifier also achieves better performance with the area under the receiver operating characteristic (ROC) curve (AUC) and F- measure equal to 0.999 and 0.993 for MIT-BIH database and 1 and 0.999 for and St. Petersburg Institute of Cardiological Technics 12-lead Arrhythmia Database, respectively. Obtained results demonstrate that the proposed system has capacity for reliable classification of ECG signals, and to assist the clinicians for making an accurate diagnosis of cardiovascular disorders (CVDs).

  • 134.
    Alkeryd, Martin
    Linköpings universitet, Institutionen för systemteknik.
    Evaluation of Position Sensing Techniques for an Unmanned Aerial Vehicle2006Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use of Unmanned Aerial Vehicles (UAVs) has rapidly increased over the last years. This has been possible mainly due to the increased computing power of microcontrollers and computers. An UAV can be used in both civilian and military areas, for example surveillance and intelligence. The UAV concerned in this master's thesis is a prototype and is currently being developed at DST Control AB in Linköping.

    With the use of UAVs, the need for a positioning and navigation system arises. Inertial sensors can often give a good position estimation, however, they need continuous calibration due to error build-up and drift in gyros. An external reference is needed to correct for this drift and other errors. The positioning system investigated in this master's thesis is supposed to work in an area defined by an inverted cone with the height of 25m and a diameter of 10m.

    A comparison of different techniques suitable for position sensing has been performed. These techniques include the following: a radio method based on the Instrument Landing System (ILS), an optical method using a Position Sensing Detector (PSD), an optical method using the Indoor GPS system, a distance measurement method with ultrasound and also a discussion of the Global Positioning System (GPS).

    An evaluation system has been built using the PSD sensor and tests have been performed to evaluate its possibilities for positioning. Accuracy in the order of a few millimetres has been achieved in position estimation with the evaluation system.

  • 135.
    Allström, Andreas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Highway Traffic State Estimation and Short-term Prediction2016Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Traffic congestion is increasing in almost all large cities, leading to a number of negative effects such as pollution and delays. However, building new roads is not a feasible solution. Instead, the use of the existing road network has to be optimized, together with a shift towards more sustainable transport modes. In order to achieve this there are several challenges that needs to be addressed. One challenge is the ability to provide accurate information about the current and future traffic state. This information is an essential input to the traffic management center and can be used to influence the choices made by the travelers. Accurate information about the traffic state on highways, where the potential to manage and control the traffic in general is very high, would be of great significance for the traffic managers. It would help the traffic managers to take action before the system reaches congestion and limit the effects of it. At the same time, the collection of traffic data is slowly shifting from fixed sensors to more probe based data collection. This requires an adaptation and further development of the traditional traffic models in order for them to handle and take advantage of the characteristics of all types of data, not just data from the traditionally used fixed sensors.

    The objective of this thesis is to contribute to the development and implementation of a model for estimation and prediction of the current and future traffic state and to facilitate an adaptation of the model to the conditions of the highway in Stockholm. The model used is a version of the Cell Transmission Model (CTM-v) where the velocity is used as the state variable. Thus, together with an Ensemble Kalman Filter (EnKF) it can be used to fuse different types of point speed measurements. The model is developed to run in real-time for a large network. Furthermore, a two-stage process used to calibrate the model is implemented. The results from the calibration and validation show that once the model is calibrated, the estimated travel times corresponds well with the ground truth travel times collected from Bluetooth sensors.

    In order to produce accurate short-term predictions for various networks and conditions it is vital to combine different methods. We have implemented and evaluated a hybrid prediction approach that assimilates parametric and non-parametric short-term traffic state prediction. To predict mainline sensor data we use a neural network, while the CTM-v is ran forward in time in order to predict future traffic states. The results show that both the hybrid approach and the CTM-v prediction without the additional predicted mainline sensor data is superior to a naïve prediction method for longer prediction horizons.

  • 136.
    Almfors, Johan
    Linköpings universitet, Institutionen för systemteknik.
    A Pre-study in Programmable Logic for use in fast Trigger Based Data Communication2005Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This Bachelor thesis is a pre-study of the possibilities of using programmable logic in the purpose to enable fast trigger based data communication. Triggerbased data communication is in this case referred to a context where the processed data is stored and examined so when the trig situation appears the data should be able read out to a computer for evaluating. The purpose of this thesis is to find difficult and time consuming elements but also to find elements that is well suited for implementation in programmable logic. The work should also support further development and verification of trig functionalities and additional hardware. This with the intent of constructing an Ethernet based oscilloscope.

    The result of this thesis is a conclusion that programmable logic is well suited for many of the implemented logic function

  • 137.
    Almgren, Erik
    Linköpings universitet, Institutionen för systemteknik.
    Sensor Fusion for Enhanced Lane Departure Warning2006Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    A lane departure warning system relying exclusively on a camera has several shortcomings and tends to be sensitive to, e.g., bad weather and abrupt manoeuvres. To handle these situations, the system proposed in this thesis uses a dynamic model of the vehicle and integration of relative motion sensors to estimate the vehicle’s position on the road. The relative motion is measured using vision, inertial, and vehicle sensors. All these sensors types are affected by errors such as offset, drift and quantization. However the different sensors are sensitive to different types of errors, e.g., the camera system is rather poor at detecting rapid lateral movements, a type of situation which an inertial sensor practically never fails to detect. These kinds of complementary properties make sensor fusion interesting. The approach of this Master’s thesis is to use an already existing lane departure warning system as vision sensor in combination with an inertial measurement unit to produce a system that is robust and can achieve good warnings if an unintentional lane departure is about to occur. For the combination of sensor data, different sensor fusion models have been proposed and evaluated on experimental data. The models are based on a nonlinear model that is linearized so that a Kalman filter can be applied. Experiments show that the proposed solutions succeed at handling situations where a system relying solely on a camera would have problems. The results from the testing show that the original lane departure warning system, which is a single camera system, is outperformed by the suggested system.

  • 138.
    Almgren, Johan
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Elingsbo, Gustav
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Route Based Optimal Control Strategy for Plug-In Hybrid Electric Vehicles2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    More restrictive emission legislations, rising fuel prices and the realisation that oil is a limited resource have lead to the emergence of the hybrid electric vehicles.To fully utilise the potential of the hybrid electric vehicles, energy management strategies are needed. The main objective of the strategy is to ensure that the limited electric energy is utilised in an efficient manner.This thesis develops and evaluates an optimisation based energy management strategy for plug-in hybrid electric vehicles. The optimisation methods used are based on a dynamic programming and ECMS approach. The strategy is validated against Vsim, Volvo Cars' performance and fuel consumption analysis tool as well as against strategies where parts of the optimisation is replaced by logic. The results show that the developed strategy consumes less fuel both compared to the corresponding Vsim strategy and the logic strategies.

  • 139.
    Almgren, Magnus
    et al.
    Department of computer science and engineering, Chalmers university of technology, Gothenburg.
    Andersson, Peter
    FOI, Swedish Defence Research Agency, Linköping, Sweden.
    Björkman, Gunnar
    Stockholms stad / Kungliga Tekniska Högskolan, KTH, Stockholm.
    Ekstedt, Mathias
    Industrial Information and Control Systems, Royal Institute of Technology, KTH, Stockholm.
    Hallberg, Jonas
    FOI, Swedish Defence Research Agency, Linköping, Sweden.
    Nadjm-Tehrani, Simin
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Westring, Eric
    FOI, Swedish Defence Research Agency, Linköping, Sweden.
    RICS-el: Building a National Testbed for Research and Training on SCADA Security2019Inngår i: Critical Information Infrastructures Security: 13th International Conference, CRITIS 2018, Kaunas, Lithuania, September 24-26, 2018, Revised Selected Papers / [ed] Eric Luiijf, Inga Žutautaitė and Bernhard Hämmerli, Springer, 2019, s. 219-225Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Trends show that cyber attacks targeting critical infrastructures are increasing, but security research for protecting such systems are challenging. There is a gap between the somewhat simplified models researchers at universities can sustain contra the complex systems at infrastructure owners that seldom can be used for direct research. There is also a lack of common datasets for research benchmarking. This paper presents a national experimental testbed for security research within supervisory control and data acquisition systems (SCADA), accessible for both research training and experiments. The virtualized testbed has been designed and implemented with both vendor experts and security researchers to balance the goals of realism with specific research needs. It includes a real SCADA product for energy management, a number of network zones, substation nodes, and a simulated power system. This environment enables creation of scenarios similar to real world utility scenarios, attack generation, development of defence mechanisms, and perhaps just as important: generating open datasets for comparative research evaluation.

  • 140.
    Almquist, Mathias
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Almquist, Viktor
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    A study on Android games: 3G energy consumption, CPU-utilization and system calls2015Independent thesis Basic level (university diploma), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    The popularity of mobile games has increased drastically during the recent years andmany people use them as their main source of entertainment. Mobile gamescommunicate with other devices over the network which consumes a lot of energy,especially when connected to cellular networks (e.g., 3G). This high energy expensecan feel unjustified to the player since always-on network connectivity is not requiredin order to play most games.Furthermore, the number of malware-infected applications in offical applicationstores has increased significantly in the recent years. These malware-infectedapplications can gain unrestricted access and control of users phones which can be athreat to security. Information about the behaviour characteristics of games can beused to develop or improve systems for detecting malware applications.In this thesis, 20 popular Android games are analysed with a focus on the datacommunication, CPU utilization and system call behaviour. The main subject of thedata communication study is the 3G communication energy consumed by games. Thesystem call study aims at quantifying the number and type of calls used by games.This may be useful in a further study of harmful behaviour by apps.The profiling results presented in this report show that the communication energyvaries drastically among games. Games with a very similar gameplay can consumevery different amounts of energy which indicates that there is room for improvementsin many of the games. Ad-free games consume significantly less energy than gamesthat use in-app advertisements. The results show that improving the advertisementfetching policy could reduce the energy consumption of these games. The majority ofthe games can be played without network connectivity and therefore thecommunication energy consumed could be completely avoided. The thesis alsoshows that games use a wide variety of system calls and that many of the system callsare common among the games.

  • 141.
    Almquist, Mathias
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Almquist, Viktor
    Linköpings universitet, Institutionen för datavetenskap.
    Analysis of 360° Video Viewing Behaviours2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis we study users' viewing motions when watching 360° videos in order to provide information that can be used to optimize future view-dependent streaming protocols. More specifically, we develop an application that plays a sequence of 360° videos on an Oculus Rift Head Mounted Display and records the orientation and rotation velocity of the headset during playback. The application is used during an extensive user study in order to collect more than 21 hours of viewing data which is then analysed to expose viewing patterns, useful for optimizing 360° streaming protocols. 

  • 142.
    Almquist, Mathias
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Almquist, Viktor
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Vergara Alonso, Ekhiotz Jon
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Nadjm-Tehrani, Simin
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Communication Energy Overhead of Mobiles Games2015Inngår i: MobiGames '15: Proceedings of the 2nd Workshop on Mobile Gaming, Association for Computing Machinery (ACM), 2015, s. 1-6Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Although a significant proportion of the mobile apps are games there has been little attention paid to their specific characteristics with respect to communication energy. In this paper we select 20 mobile games among the top 100 free Android games, and study their data patterns and communication energy use over a total of 25 hours of playing. The analysis of the energy for communication over 3G networks indicates that there is a wide variation among the games, the largest footprint being 8 times higher than the lowest one. The results also indicates both app-specific and category-specific relations between data pattern and energy use, as well as variations in CPU utilisation.

  • 143.
    Almquist, Tobias
    Linköpings universitet, Institutionen för systemteknik.
    Layout-generator för sifferseriell tvåportsadaptor2002Independent thesis Basic level (professional degree)Oppgave
    Abstract [sv]

    Vid sifferseriell aritmetik används ett antal parallella bitar för varje siffra. För att jämföra prestanda och effektförbrukning i förhållande till antalet bitar behövde Institutionen för systemteknik (ISY) en layout-generator för att enkelt kunna generera layout för en sifferseriell tvåportsadaptor. Layouten skulle göras i 0.18 mikrometer process. Antalet inkommande databitar och antalet koefficientbitar skulle vara variabelt. Stor vikt lades vid planeringen av layouten för att genereringen av adaptorn skulle fungera smidigt oberoende av de variabla parametrarna. Kod skrevs för att koppla samman layout-instanserna och för att förenkla adaptorn.

  • 144.
    Almqvist, Erik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik.
    Airborne mapping using LIDAR2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Mapping is a central and common task in robotics research. Building an accurate map without human assistance provides several applications such as space missions, search and rescue, surveillance and can be used in dangerous areas. One application for robotic mapping is to measure changes in terrain volume. In Sweden there are over a hundred landfills that are regulated by laws that says that the growth of the landfill has to be measured at least once a year.

    In this thesis, a preliminary study of methods for measuring terrain volume by the use of an Unmanned Aerial Vehicle (UAV) and a Light Detection And Ranging (LIDAR) sensor is done. Different techniques are tested, including data merging strategies and regression techniques by the use of Gaussian Processes. In the absence of real flight scenario data, an industrial robot has been used fordata acquisition. The result of the experiment was successful in measuring thevolume difference between scenarios in relation to the resolution of the LIDAR. However, for more accurate volume measurements and better evaluation of the algorithms, a better LIDAR is needed.

  • 145. Almqvist, Erik
    et al.
    Eriksson, Daniel
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Lundberg, Andreas
    Nilsson, Emil
    Wahlström, Niklas
    Frisk, Erik
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Krysander, Mattias
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Solving the ADAPT Benchmark Problem - A Student Project Study2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes a solution to the Advanced Diagnosis and Prognostics testbed (ADAPT) diagnosis benchmark problem. One main objective was to study and discuss how engineering students, with no diagnosis research background, would solve a challenging diagnosis problem. The study was performed within the framework of a final year project course for control engineering students. A main contribution of the work is the discussion on the development process used by the students. The solution is based on physical models of components and includes common techniques from control theory, like observers and parameter estimators, together with established algorithms for consistency based fault isolation. The system is fully implemented in C++ and evaluated, using the DXC software platform, with good diagnosis performance.

  • 146.
    Almqvist, Håkan
    Linköpings universitet, Institutionen för systemteknik.
    Automatic bucket fill2009Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report contains the first step towards a complete, fully autonomous, robust bucket fill regulator for a wheel loader working with gravel materials.

    The bucket fill procedure is the most critical part of the work cycle of a wheel loader. It is a task that has a long learning curve and also is weary, even for experienced drivers. The automation of it could therefore have a big impact on the cost effectiveness for wheel loaders and for the comfort of the drivers.

    In this report, a suggestion for the complete solution of an automatic bucket fill regulator is presented. A regulator prototype is also constructed with a Volvo L120F as the base. The scope for the prototype is limited to one type of gravel material and quite optimal conditions for the wheel loader, but the complete solution is kept in mind throughout the synthesis. The constructed regulator is prepared for expansion, but the implementation and field testing is limited to the scope.

  • 147.
    Almqvist, Tom
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Utvärdering av metoder för temporär lagring av data i en webbapplikation2018Independent thesis Basic level (university diploma), 10,5 poäng / 16 hpOppgave
    Abstract [sv]

    I databasapplikationer är det viktigt att kunna minska belastningen på en databas i syfte att minska responstiden. Detta kan exempelvis åstadkommas med hjälp av olika metoder för temporär lagring av data, något som studerats i detta arbete. De metoder som utvärderats och jämförts i detta arbete är Redis och memcached. Utvärderingen jämförde Redis och memcached med avseende på minnesanvändning, CPU-användning och tidsåtgång för hämtning av data i respektive cache. Dessa egenskaper beräknades med hjälp av verktygen SYSSTAT och valgrind. Det visade sig i slutändan att den interna fragmenteringen i memcached är dess största nackdel, medan Redis är något långsammare än memcached när det gäller att hämta stora mängder data. Utifrån de resultat som anskaffats var det tänkt att använda den metod som är mest lämpad för SysPartners ändamål, vilket ansågs vara Redis.

  • 148.
    Almén, Fredrik
    Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Band structure computations for dispersive photonic crystals2007Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    Photonic crystals are periodic structures that offers the possibility to control the propagation of light.

    The revised plane wave method has been implemented in order to compute band structures for photonic crystals. The main advantage of the revised plane wave method is that it can handle lossless dispersive materials. This can not be done with a conventional plane wave method. The computational challenge is comparable to the conventional plane wave method.

    Band structures have been calculated for a square lattice of cylinders with different parameters. Both dispersive and non-dispersive materials have been studied as well as the influence of a surface roughness.

    A small surface roughness does not affect the band structure, whereas larger inhomogeneities affect the higher bands by lowering their frequencies.

  • 149.
    Almén, Marcus
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Driver Model for Mission-Based Driving Cycles2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    When further demands are placed on emissions and performance of cars, trucks and busses, the vehicle manufacturers are looking to have cheap ways to evaluate their products for specific customers' needs. Using simulation tools to quickly compare use cases instead of manually recording data is a possible way forward. However, existing traffic simulation tools do not provide enough detail in each vehicle for the driving to represent real life driving patterns with regards to road features.

    For the purpose of this thesis data has been recorded by having different people drive a specific route featuring highway driving, traffic lights and many curves. Using this data, models have then been estimated that describe how human drivers adjust their speed through curves, how long braking distances typically are with respect to the driving speed, and the varying deceleration during braking sequences. An additional model has also been created that produces a speed variation when driving on highways. In the end all models are implemented in Matlab using a traffic control interface to interact with the traffic simulation tool SUMO.

    The results of this work are promising with the improved simulation being able to replicate the most significant characteristics seen from human drivers when approaching curves, traffic lights and intersections.

  • 150.
    Alner, Klas
    Linköpings universitet, Institutionen för systemteknik.
    Layoutgenerator för en multiplikator i "overturned stairs" trädstruktur2003Independent thesis Basic level (professional degree)Oppgave
    Abstract [sv]

    Multiplikatorer används ofta som ett byggblock vid konstruktion av kretsar som digitala filter, FFT-processorer och aritmetiska enheter. Olika trädstrukturer används i"höghastighet"applikationer för multiplikatorer. En typ av träd,"overturned-stairs"(OS) som är ett adderarträd av första ordningen har uppvisat lika optimal prestanda med avseende på hastighet som Wallace-träd, vid 18 eller färre ingångar. I moderna integrerade kretsar, ger ledningar och kopplingar upphov till fördröjningar och parasitiska laster. I en jämförelse mellan Wallace-träd, och OS1-träd har det sistnämda kortare och mindre komplicerad ledningsdragningar och är därför mer ändamålsenlig för VLSI implementationer.

1234567 101 - 150 of 7492
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf