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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design of control system for metal dosing and transfer

Haichun, Cao January 2009 (has links)
<p>Developing an automatic control system from original stage is quite time consuming, a lot of works must be done before the final result, in order to save designing time and money, a systematic way to carry through development is necessary. This project will give an experience about using a systemic method to develop an automatic control system for metal dosing and transfer from original stage. The project will be divided into several different phases, and each phase focuses on some different important tasks. In this project a research of PLCs and stepper motors and then give suitable suggestions of selection of them have been done. One of important roles for this project is to develop a prototype machine and use computer to model and simulate prototype and whole machine, therefore, in this project, using SDL assistant with Matlab to model and simulate both prototype and whole machine have been processed. Because of some unexpected condition, this project doesn’t include real PLC programming.</p>
2

Enabling autonomous envionmental measurement systems with low-power wireless sensor networks

Bader, Sebastian January 2011 (has links)
Wireless Sensor Networks appear as a technology, which provides the basisfor a broad field of applications, drawing interest in various areas. On theone hand, they appear to allow the next step in computer networks, buildinglarge collections of simple objects, exchanging information with respect totheir environment or their own state. On the other hand, their ability tosense and communicate without a fixed physical infrastructure makes theman attractive technology to be used for measurement systems.Although the interest inWireless Sensor Network research is increasing,and new concepts and applications are being demonstrated, several fundamentalissues remain unsolved. While many of these issues do not requireto be solved for proof-of-concept designs, they are important issues to beaddressed when referring to the long-term operation of these systems. Oneof these issues is the system’s lifetime, which relates to the lifetime of thenodes, upon which the system is composed.This thesis focuses on node lifetime extension based on energy management.While some constraints and results might hold true from a moregeneral perspective, the main application target involves environmental measurementsystems based onWireless Sensor Networks. Lifetime extensionpossibilities, which are the result of application characteristics, by (i) reducingenergy consumption and (ii) utilizing energy harvesting are to be presented.For energy consumption, we show howprecise task scheduling due to nodesynchronization, combined with methods such as duty cycling and powerdomains, can optimize the overall energy use. With reference to the energysupply, the focus lies on solar-based solutions with special attentionplaced on their feasibility at locations with limited solar radiation. Furtherdimensioning of these systems is addressed.It will be shown, that for the presented application scenarios, near-perpetualnode lifetime can be obtained. This is achieved by focusing on efficient resourceusage and by means of a carefully designed energy supply.
3

Development of equipment for measuring Ocular Micro-Tremor

Muqdisi, Menhal January 2009 (has links)
No description available.
4

Characterization of Low Cost Printed Sensors for Smart Packaging

Unander, Tomas January 2008 (has links)
<p>Currently there are very significant interests in printed electronics in the world. The possibility to produce electronics in a roll to roll printing process will considerably reduce the cost of the electronic devices. However, these new devices will most probably not replace the traditional silicon based electronics, but will be a complement in low cost applications such as in intelligent packages and other printable media. One interesting area is printable low cost sensors that add value to packages. In this thesis a study of the performance of low cost sensors is presented. The sensors were fabricated using commercial printing processes used in the graphical printing business. The sensors were characterized and evaluated for the intended application. The evaluated sensors were moisture sensing sensor solutions and touch sensitive sensor solutions.</p><p>A printable touch sensitive sensor solution is presented where the sensor is incorporated into a high quality image such as in point of sales displays. The sensor solution showed good touch sensitivity at a variety of humidity levels. Four printed moisture sensor concepts are presented and characterized. Firstly, a moisture sensor that shows good correlation to the moisture content of cellulose based substrates. Secondly, a sensor that measures the relative humidity in the air, the sensor has a measuring accuracy of 0.22% at high relative humidity levels. Thirdly, a moisture sensor that utilizes unsintered silver nano-particles to measure the relative humidity in the air, the sensor has a linear response at very low relative humidity levels. And fourth, an action activated energy cell that provides power when activated by moisture. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized. The remote sensor solution works both with passive and semi-passive RFID systems. The study shows that it is possible to manufacture low cost sensors in commercial printing processes.</p> / <p>Det är för närvarande ett stort intresse för tryckt elektronik. Att kunna tillverka elektroniska komponenter i en rulle till rulle process möjliggör en reducering av tillverkningskostnaden. Dessa nya komponenter kommer sannolikt inte konkurrera ut den traditionella kiselbaserade elektroniken utan kommer att kunna komplimentera kiselelektronik i segment där kostnaden är väldigt viktig som i intelligenta förpackningar och andra tryckta medier. Ett intressant område är tryckta sensorer som kan addera värde till förpackningar. I denna avhandling presenteras en studie kring tryckta sensorer som kan tillverkas till låg kostnad. Sensorerna är tillverkade i kommersiella grafiska tryckpressar. Sensorerna karakteriseras och utvärderas för de applikationer som de är tänkta för. I denna avhandling har fuktsensorer och beröringskänsliga sensorer undersökts.</p><p>Det presenteras en tryckt beröringskänslig sensor som integreras i ett högkvalitativt grafiskt tryck. Denna sensor är tänkt att användas i reklamskyltar för att skapa interaktivitet. Sensorn har en bra känslighet vid varierande fukthalter. Även fyra fuktsensorer presenteras och utvärderas. Den första sensorn mäter fukthalten i cellulosabaserade substrat och visar en bra korrelation till fukthalten i substratet. Den andra sensorn mäter den relativa fukten i luften, denna sensor har en mätnoggrannhet på 0.22% för höga fukthalter. Den tredje sensorn använder partiklar i nanostorlek för att mäta fukthalten i luften. Denna sensor fungerar väldigt bra vid låga fukthalter. Den fjärde sensorn är en energicell som producerar el när den blir fuktig. Även en fuktsensor som kan läsas av på håll utvärderas. Detta sensorkoncept är baserad på vanliga RFID taggar och kan användas med både passiva och semi-passiva taggar. Denna avhandling visar att det är möjligt att tillverka sensorer till en låg kostnad in en traditionell grafisk tryckpress.</p>
5

Analys av för- och nackdelar vid användning av skärmade eller oskärmade kablar för strömförsörjning av flygplatsbelysning

Malki, Antoinette January 2007 (has links)
<p>Under examensarbetet på Luftfartsverket i Norrköping har beräkningar, mätningar och teoretiska analyser gjorts på parallella seriesystem. Detta har givit kunskap om kablarnas uppbyggnad och användning samt induktiva kopplingen mellan de parallella kablarna. All nödvändiga fakta bygger på mina observationer och anteckningar från dessa beräkningar och teoretiska analyser. Utifrån teoretiska analyser och Maxwellsekvationer skall flera frågeställningar besvaras under förutsättningen att undersöka de för- och nackdelar som skärmade kablar ger gentemot oskärmade kablar i ett personsäkerhetsperspektiv och med avseende på störningskänslighet. Kalkyler har tagits ifrån olika litteratur, vilket har resulterat till olika uträkningar på skärmade kablar och oskärmade kablar. Sedan har de olika beräkningarna jämförts med praktiska mätningar som utfördes ute på två flygplatser, nämligen Norrköpings flygplats (med typen oskärmade kablar) och Jönköpings flygplats (med typen skärmade kablar). Personsäkerheten kunde sedan klarläggas utifrån resultaten av såväl beräkningar som mätningar. Resultaten och slutsatser har tagits fram enligt olika matematiska presentationer och teoretiska analyser, då jämförandet mellan skärmade och oskärmade kablar har gjords. Reduktionsfaktor ger en storlek på hur effektivt skärmen är, dvs. för en kabel utan metallmantel är reduktionsfaktorn k=1. Om kabel däremot omsluts av en metallskärm, är reduktionsfaktorn kə. Reduktionsfaktor: 0.9995 (Utan jordade brunnar) Reduktionsfaktor: 0.91 (Med jordade brunnar) Reduktionsfaktor: 0.82 (Mätningar) Med hänsyn till resultaten ser man att reduktionsfaktorn är mindre än 1 för alla tre ovan nämnda, vilket innebär att kabeln är en ganska bra skärm. Samtidigt är reduktionsfaktorn ganska nära 1, vilket indikerar att skillnaden mellan skärmade och oskärmade kablar inte är stort. Detta leder till att man i praktiken inte bör räkna med någon reduktion. Beräkningarna och mätningar som har gjords på inducerad spänning och inducerad ström indikerar att den induktiva kopplingen mellan de parallella kablarna är låg. Den inducerade spänningen blev 14V och inducerade strömmen 156mA för oskärmad kabel och 12V samt 80mA för skärmad kabel.</p>
6

Characterization of Low Cost Printed Sensors for Smart Packaging

Unander, Tomas January 2008 (has links)
Currently there are very significant interests in printed electronics in the world. The possibility to produce electronics in a roll to roll printing process will considerably reduce the cost of the electronic devices. However, these new devices will most probably not replace the traditional silicon based electronics, but will be a complement in low cost applications such as in intelligent packages and other printable media. One interesting area is printable low cost sensors that add value to packages. In this thesis a study of the performance of low cost sensors is presented. The sensors were fabricated using commercial printing processes used in the graphical printing business. The sensors were characterized and evaluated for the intended application. The evaluated sensors were moisture sensing sensor solutions and touch sensitive sensor solutions. A printable touch sensitive sensor solution is presented where the sensor is incorporated into a high quality image such as in point of sales displays. The sensor solution showed good touch sensitivity at a variety of humidity levels. Four printed moisture sensor concepts are presented and characterized. Firstly, a moisture sensor that shows good correlation to the moisture content of cellulose based substrates. Secondly, a sensor that measures the relative humidity in the air, the sensor has a measuring accuracy of 0.22% at high relative humidity levels. Thirdly, a moisture sensor that utilizes unsintered silver nano-particles to measure the relative humidity in the air, the sensor has a linear response at very low relative humidity levels. And fourth, an action activated energy cell that provides power when activated by moisture. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized. The remote sensor solution works both with passive and semi-passive RFID systems. The study shows that it is possible to manufacture low cost sensors in commercial printing processes. / Det är för närvarande ett stort intresse för tryckt elektronik. Att kunna tillverka elektroniska komponenter i en rulle till rulle process möjliggör en reducering av tillverkningskostnaden. Dessa nya komponenter kommer sannolikt inte konkurrera ut den traditionella kiselbaserade elektroniken utan kommer att kunna komplimentera kiselelektronik i segment där kostnaden är väldigt viktig som i intelligenta förpackningar och andra tryckta medier. Ett intressant område är tryckta sensorer som kan addera värde till förpackningar. I denna avhandling presenteras en studie kring tryckta sensorer som kan tillverkas till låg kostnad. Sensorerna är tillverkade i kommersiella grafiska tryckpressar. Sensorerna karakteriseras och utvärderas för de applikationer som de är tänkta för. I denna avhandling har fuktsensorer och beröringskänsliga sensorer undersökts. Det presenteras en tryckt beröringskänslig sensor som integreras i ett högkvalitativt grafiskt tryck. Denna sensor är tänkt att användas i reklamskyltar för att skapa interaktivitet. Sensorn har en bra känslighet vid varierande fukthalter. Även fyra fuktsensorer presenteras och utvärderas. Den första sensorn mäter fukthalten i cellulosabaserade substrat och visar en bra korrelation till fukthalten i substratet. Den andra sensorn mäter den relativa fukten i luften, denna sensor har en mätnoggrannhet på 0.22% för höga fukthalter. Den tredje sensorn använder partiklar i nanostorlek för att mäta fukthalten i luften. Denna sensor fungerar väldigt bra vid låga fukthalter. Den fjärde sensorn är en energicell som producerar el när den blir fuktig. Även en fuktsensor som kan läsas av på håll utvärderas. Detta sensorkoncept är baserad på vanliga RFID taggar och kan användas med både passiva och semi-passiva taggar. Denna avhandling visar att det är möjligt att tillverka sensorer till en låg kostnad in en traditionell grafisk tryckpress.
7

Photonic Devices and Applications based on Intersubband Transitions and Electromagnetically Induced Transparency

Jänes, Peter January 2006 (has links)
Although photonic devices have experienced a rapid development lately, there is still room for substantial improvements in performance. From a telecommunications perspective, improvements in speed, size, integration and power consumption are desired. There is also a general interest in photonic devices with new functionalities. Being a key component in fiber-optic systems, high-speed optical modulators often initiate the development towards higher bit-rates. The technology of current state-of-the-art modulators has matured suggesting new paths of development. In this thesis we investigate the potential of modulators based on intersubband (IS) transitions in quantum wells (QWs). Specific QW designs are suggested and complete modulator structures are simulated. IS absorption is also experimentally characterized. Absorption linewidth is critical for IS modulator performance since narrow linewidth implies high bandwidth and/or small driving voltage. High material quality is important, since linewidth is typically limited by well-width fluctuations and interface roughness. A mid-IR AlGaAs/GaAs-modulator is proposed having a RC-limited bandwidth of 130 GHz and a peak-to-peak voltage of 0.9 V. Experimentally, Stark shift is measured in InAlAs/InAlGaAs/InGaAs step QWs at λ ~ 6 μm predicting that an IS modulator based on this material would have a bandwidth of 90 GHz and a peak-to-peak voltage of 0.9 V. IS absorption at 1.55 μm requires material combinations with high conduction-band offset. Simulations of an InGaAs/InAlAs/AlAsSb-modulator predict a bandwidth of 90 GHz and a peak-to-peak voltage of 2.0 V. Experimental studies of IS absorption in AlN/GaN QWs are presented. IS absorption at 1.5-3.4 μm with linewidth below 100 meV is measured for well widths between 15-54 Å. Subpeaks corresponding to well-width fluctuations on the monolayer scale are identified with linewidths of ~60 meV. Agreement between theoretical calculations and measured spectra is encouraging. Theoretical simulations together with measured absorption linewidths suggest that high performance IS modulators operating at 1.55 μm are realizable. Photonic devices with new functionalities are addressed by investigating electromagnetically induced transparency (EIT) theoretically and considering potential applications based on EIT. Simulations of two-dimensional pulse-propagation based on the Maxwell-Bloch equations are performed with a focus on storing and reading out optical pulses. We explicitly formulate the phase-matching conditions for reading out stored pulses in a new direction and propose a serial-to-parallel converter based on this. For slow-light devices, e.g. optical buffers, we identify and analyze two main limitations on the medium bandwidth; the frequency dependent absorption and the group velocity dispersion. Since large bandwidth and large delay are contradictory requirements, the delay bandwidth product is considered. Analytical expressions are derived and analyzed and verified by simulations on pulse propagation. Insertion of parameters relevant for semiconductors indicates that development of materials with long coherence times are necessary for realizing optical buffers based on EIT. / QC 20100903
8

Integrated Logic Synthesis Using Simulated Annealing

Färm, Petra January 2007 (has links)
A conventional logic synthesis flow is composed of three separate phases: technologyindependent optimization, technology mapping, and technology dependentoptimization. A fundamental problem with such a three-phased approach is thatthe global logic structure is decided during the first phase without any knowledge ofthe actual technology parameters considered during later phases. Although technologydependent optimization algorithms perform some limited logic restructuring,they cannot recover from fundamental mistakes made during the first phase, whichoften results in non-satisfiable solutions.We present a global optimization approach combining technology independentoptimization steps with technology dependent objectives in an annealing-basedframework. We prove that, for the presented move set and selection distribution, detailedbalance is satisfied and thus the annealing process asymptotically convergesto an optimal solution. Furthermore, we show that the presented approach cansmoothly trade-off complex, multiple-dimensional objective functions and achievecompetitive results. The combination of technology independent and technologydependent objectives is handled through dynamic weighting. Dynamic weightingreflects the sensitivity of the local graph structures with respect to the actual technologyparameters such as gate sizes, delays, and power levels. The results showthat, on average, the presented advanced annealing approach can improve the areaand delay of circuits optimized using the Boolean optimization technique providedby SIS with 11.2% and 32.5% respectively.Furthermore, we demonstrate how the developed logic synthesis framework canbe applied to two emerging technologies, chemically assembled nanotechnology andmolecule cascades. New technologies are emerging because a number of physicaland economic factors threaten the continued scaling of CMOS devices. Alternativesto silicon VLSI have been proposed, including techniques based on molecularelectronics, quantum mechanics, and biological processes. We are hoping that ourresearch in how to apply our developed logic synthesis framework to two of theemerging technologies might provide useful information for other designers movingin this direction. / QC 20100709
9

Design of control system for metal dosing and transfer

Haichun, Cao January 2009 (has links)
Developing an automatic control system from original stage is quite time consuming, a lot of works must be done before the final result, in order to save designing time and money, a systematic way to carry through development is necessary. This project will give an experience about using a systemic method to develop an automatic control system for metal dosing and transfer from original stage. The project will be divided into several different phases, and each phase focuses on some different important tasks. In this project a research of PLCs and stepper motors and then give suitable suggestions of selection of them have been done. One of important roles for this project is to develop a prototype machine and use computer to model and simulate prototype and whole machine, therefore, in this project, using SDL assistant with Matlab to model and simulate both prototype and whole machine have been processed. Because of some unexpected condition, this project doesn’t include real PLC programming.
10

Development of equipment for measuring Ocular Micro-Tremor

Muqdisi, Menhal January 2009 (has links)
No description available.

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