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1
Lee, Byung K. "Tracking of truck flows for drayage efficiency analysis." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1603103.
Abstract:
Inefficient port drayage causes high costs in addition to congestion and pollution. To identify the causes of inefficiency in port drayage, we developed a mobile application, which utilizes a Global Point System (GPS), Bluetooth and some driver inputs to track the manner in which the drays move, such as picking up a loaded container or delivering an empty one. A web application is used to receive data from the mobile devices, interprets the data to determine whether or not the data points are in or out of range of port terminals, stores the data in a database and provides visualization of point locations on Google Maps. The collected data are then analyzed in order to pinpoint any trouble areas, find the cause, and recommend solutions where appropriate. In this work, we describe the software development process in both the mobile and the web applications and report results of our analysis based on the collected data.
2
Aleman, Adriana. "Efficiency of Internal Capital Markets: Evidence from Tracking Stocks." Honors in the Major Thesis, University of Central Florida, 2003. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/408.
Abstract:
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Arts and Sciences
Finance
3
Morfeldt, Johannes. "Tracking Emissions Reductions and Energy Efficiency in the Steel Industry." Doctoral thesis, KTH, Energi och klimatstudier, ECS, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-205882.
Abstract:
The iron and steel industry has become increasingly globalised. Market conditions are also changing and de-carbonisation of production is challenging. The objective of this thesis is to assess how energy efficiency and greenhouse gas emissions reductions can be promoted and effectively monitored in the steel industry. The thesis contributes with analyses based on the Malmquist Productivity Index for a top-down analysis of the energy efficiency of EU Member States’ iron and steel production, and Partial Least Squares regression for bottom-up assessments of different monitoring tools. The thesis also contributes with a scrap availability assessment module to enhance the energy system model ETSAP-TIAM. The first phase of the research showed that future production needs to shift towards innovative low-CO2 technologies even when all available recycled material is fully used. Techniques using carbon capture and storage (CCS) as well as hydrogen-based technologies can be expected to become economically viable under tightened climate policies. The second phase of the research showed that current indicators are insufficient. System boundaries of energy use and emissions data do not align with production statistics. Indicators based on energy use or emissions in relation to production in physical terms may be useful to track specific processes. However, current indicators fail to reflect the companies’ product mix. Enhanced energy and climate indicators that adjust for the product mix provide better estimates while failing to reflect the increasing globalisation. Effective monitoring of industrial transformation will be increasingly important as pressure from climate policy via global CO2-pricing is unlikely in the short term. Current or enhanced indicators do not fully capture industrial transformation and are not recommended. Future research should focus on defining indicators to estimate energy use and emissions along industrial value chains in climate policy contexts.Järn- och stålindustrin har blivit alltmer globaliserad. Marknadsvillkoren förändras samtidigt som utfasningen av fossila bränslen är utmanande. Målet med den här avhandlingen är att bedöma hur energieffektivitet och växthusgasutsläppsminskningar kan främjas och effektivt utvärderas inom stålindustrin. Avhandlingen bidrar med analyser baserade Malmquists produktivitetsindex för att analysera energieffektivitet av EU:s medlemsstaters järn- och stålproduktion, och partiell minsta- kvadrat-regression för att bedöma olika utvärderingsmått. Avhandlingen bidrar även med en modul som bedömer skrottillgång för att förbättra energisystemmodellen ETSAP-TIAM. I en första fas visade forskningen att framtida produktion behöver ställas om mot innovativa teknologier med låga CO2-utsläpp även när allt tillgängligt återvunnet material används fullt ut. Tekniker som använder koldioxidinfångning och -lagring (CCS) samt vätebaserade teknologier kan förväntas bli ekonomiskt försvarbara under åtstramade klimatpolitiska styrmedel. I en andra fas visade forskningen att nuvarande indikatorer är otillräckliga. Systemgränser för energianvändnings- och växthusgasutsläppsdata stämmer inte överens med produktionsstatistik. Indikatorer utifrån energianvändning eller utsläpp i relation till fysisk produktion kan vara användbara för att följa upp specifika processer. Nuvarande indikatorer lyckas dock inte spegla företagens produktmix. Förbättrade energi- och klimatindikatorer som justerar för produktmixen ger bättre uppskattningar, men speglar inte branschens ökande globalisering. Effektiv utvärdering av industriell transformation blir alltmer viktig då påtryckning från klimatpolitiska styrmedel via global CO2-prissättning är kortsiktigt osannolik. Nuvarande eller förbättrade indikatorer fångar inte industriell transformation fullt ut och rekommenderas inte. Framtida forskning bör fokusera på att definiera indikatorer som uppskattar energianvändning och växthusgasutsläpp längs industriella värdekedjor.
QC 20170428
4
A, Mokhti Zulhazmi Bin. "Development of a high-efficiency power amplifier for envelope tracking applications." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/98635/.
Abstract:
Complex and spectrally efficient modulation schemes present a power-efficiency challenge to base station power amplifiers due to the time-varying envelope and high peak-to-average power ratios involved. The envelope tracking architecture is one way to address this issue, where an envelope amplifier provides a dynamic, modulated supply to the power amplifier to reduce power consumption. While most research into envelope tracking focuses on the envelope amplifier, this work focuses on optimising the power amplifier design for envelope tracking using the waveform engineering approach. It studies the behaviour of a highly-efficient power amplifier mode of operation (class-F) using a relatively low-cost high voltage laterally diffused metal oxide semiconductor (HVLDMOS) technology in an envelope tracking environment. A systematic design process is formulated based on identifying the optimum amplifier load and the envelope shaping function, and then applied in the development of an actual class-F power amplifier. The fabricated power amplifier is integrated into an envelope tracking system and is able to produce one of the highest recorded efficiencies compared to current state-of-the-art envelope tracking amplifiers, which are mostly based on Gallium Nitride technology. The limitation of this design is its linearity performance, and the efficiency-linearity trade-off is analysed in detail in this work. The use of continuous mode power amplifiers in envelope tracking is also explored for high-bandwidth operation. The limitation of such a technique is posed by the device nonlinear output capacitance, and this is analysed through the use of a novel characterisation approach called voltage-pull, which is derived from an active load-pull system but uses voltage waveforms as the target instead of loads. This method is also used to investigate the possibility of exploiting the device nonlinear output capacitance as a 2nd harmonic injection source to improve power amplifier efficiency, as predicted in a novel mathematical analysis presented in this work.
5
Richard, Gaetan C. "A NEW HIGH EFFICIENCY, AGILE BEAM SCANNING, BROADBAND TRACKING ANTENNA FEED." International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/608863.
Abstract:
International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, NevadaTwo different types of tracking feeds are currently used in the majority of telemetry tracking antenna systems when autotrack operation is required. They are of the conical scanner or of the single channel monopulse family and they employ well known technologies. In broadband applications, these feeds all suffer from the same inherent degradation in efficiency caused by their inability to maintain a constant crossover loss value and by their failure to properly illuminate the reflector. In high dynamics situations they can also generate unwanted and sometimes detrimental modulation whenever on-axis tracking is not maintained. In addition, currently available versions of the conical scanner are not capable of high scan rates or of scan rate agility and they are ill-suited for use in tracking systems based on non-orthogonal axes positioners. This paper describes a new high efficiency tracking feed system based on proven conical scanner technology. Its design incorporates features such as variable crossover, steerable beam, high scan rates, scan rate agility as well as stable reference coordinate system. In addition to these features, this new feed is also capable of delivering, in all but one operational category, levels of performance superior to that achievable to date by any other implementation of the conical scanner or of the single channel monopulse technology.
6
Mahon, John P. "THE S-BAND COAXIAL WAVEGUIDE TRACKING FEED FOR ARIA." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/607612.
Abstract:
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThis paper contains a description of a new technology tracking feed and a discussion of the features which make this feed unique and allow it to perform better than any other comparable feed. Also included in this report are measured primary antenna patterns, measured and estimated phase tracking performance and estimated aperture efficiency. The latter two items were calculated by integrating the measured primary patterns.
7
Kauffman, Kyle J. "Fast target tracking technique for synthetic aperture radars." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1250263416.
8
Krishnamurthy, Balasubramanya. "A comparison of the relative efficiency of tracking signals in forecast control." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4942.
Abstract:
Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains ix, 94 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 91-94).
9
Alqarni, Mohammed. "A high efficiency photovoltaic inverter system configuration with maximum power point tracking." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12767.
Abstract:
The increase in demand for renewable energy sources has been exponential in recent years and is mainly driven by factors that include the growth of greenhouse emissions and the decline in fossil fuel reservoirs. Photovoltaic (PV) energy, one of the more prominent renewable energy sources, produces electricity directly from sunlight, noiselessly and harmlessly to the environment. Additionally, PV energy systems are easy to install and financially supported by many governments, which has helped disseminate PV technology worldwide. The total generated power from PV installations (and the number of installations) has increased more than two-fold during the past 3 years, so that now more than 177 GW of PV-generated power is delivered per year. Researchers have been led to work on the obstacles facing PV systems from different perspectives, including: installation cost, inconsistency, and conversion and interface efficiency. The aim of this thesis is to design a high-efficiency PV inverter system configuration. The contribution to the knowledge in this thesis can be divided into two parts. The first part contains a critical analysis of different maximum power point tracking (MPPT) techniques. The second part provides a detailed design of the inverter system, which consists of a boost converter and a low-frequency H-bridge. Together, the three parts in this contribution present a complete high efficiency PV inverter system. The proposed system maintains high-efficiency energy delivery by reducing the number of high-frequency switches, which waste a significant amount of energy and reduce system efficiency. In order to show the superiority of the proposed configuration, a power loss analysis comparison with the other existing configurations is presented. In addition, different scenarios have been simulated with Matlab/Simulink. The results of these simulations confirm the distinction of the proposed configuration as well as its low-loss, high-efficiency characteristics which is rated at 98.8%.
10
Gedamke, Todd. "Estimating Commercial Scallop Dredge Efficiency through Vessel Tracking, Catch Data, and Depletion Models." W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539617795.
11
Sood, Sumit. "Multiphysics modelling for online diagnosis and efficiency tracking : application to green H2 production." Thesis, Université de Lille (2018-2021), 2021. https://pepite-depot.univ-lille.fr/LIBRE/EDMADIS/2021/2021LILUB028.pdf.
Abstract:
L’hydrogène vert est le vecteur d’énergie du futur le plus prometteur car il est d’une part capté par des sources renouvelables et inépuisables qui sont les énergies éolienne et/ou solaire et d’autre part permet de meilleurs transport et stockage de l’énergie sur le long terme en bouteilles haute pression par un électrolyseur pour produire ensuite de l’électricité par des piles à combustible sans émission d’aucun polluant. La nature intermittente des SER dégrade la performance et le fonctionnement dynamique des électrolyseurs PEM et leur couplage doit être étudié afin d’assurer la disponibilité opérationnelle et la pérennité du fonctionnement des équipements par une détection précoce des défauts et l’estimation de leurs durées de vie mais aussi le suivi en ligne des performances technico économiques.L’objectif de la thèse réalisé dans le cadre du projet Européen Interreg-2 Mers E2C est de développer un modèle dynamique multi-physique d’un électrolyseur PEM, basé sur une approche Bond-Graph pour une utilisation générique pour d’autres types d’électrolyseur non seulement pour l’analyse mais aussi pour la conception de systèmes de supervision en ligne pour la détection et localisation de défauts. La modélisation des divers composants de l’électrolyseur a été réalisée sous forme de capsules Bond-Graph. Ces capsules peuvent être connectées en tenant compte de la structure du diagramme d’instrumentation pour obtenir un modèle dynamique global. Ce modèle est capable de représenter différentes configurations, du pilote de laboratoire jusqu’à l’échelle industrielle, et également de suivre l’efficacité en temps réel. Le modèle a été converti en MATLAB® Simulink pour implémentation, puis validé expérimentalement sur une cellule alimentée par une Plateforme Multi-Source Hybride comprenant des sources d’énergie solaire et éolienne. Le modèle a été adapté pour représenter et étudier la performance d’un électrolyseur à Membrane Echangeuse d’Anions, dont la configuration et l’architecture sont similaires, en collaboration avec l’Université d’Exeter. Le modèle permet également de développer des algorithmes de commande, diagnostic et pronostic ; ainsi, un diagnostic robuste des défauts est présenté dans ce travail. Une Interface Utilisateur Graphique pour la supervision en ligne incorpore le modèle et les algorithmes de diagnosticRenewable Energy Sources (RES) have emerged as a sustainable alternative to carbon-based energy sources as the world is struggling in limiting the greenhouse effect in the coming years. The use of RES, such as solar and wind, alone is non-reliable due to their intermittent nature. The surplus electricity generated during off-peak hours must be stored to tackle the problem of the unavailability of energy. Green Hydrogen (GH$_2$) generation using electrolyser running on RES has seen an increase in recent years for the storage of this surplus energy due to its advantages over conventional methods (such as batteries and ultra-capacitors) for long term storage and transport. Proton Exchange Membrane (PEM) based electrolysers are better suited for the coupling with RES as compared to the alkaline electrolysers due to their faster start-up times and fast dynamic load changing capability. The intermittent nature of RES affects the performance and operation dynamics of the PEM electrolyser and must be analysed and studied in order to make these systems more reliable and safer to use. Mathematical modelling is one of the possible solutions for studying their behavior and developing supervision algorithms.Under the framework of the E2C project of the European Interreg 2-Seas program, a generic dynamic multi-physics model of a PEM electrolyser has been proposed in this work based on Bond Graph (BG) approach. Various components of the PEM electrolyser have been modelled in the form of BG capsules. These capsules can be connected based on the piping and instrumentation diagram of the PEM electrolyser system to have a global model of the system. The developed model is capable of representing different configurations of PEM electrolysers ranging from laboratory scale to industrial scale. The model is also capable of facilitating efficiency tracking in real-time. The developed model in the BG form has been converted into MATLAB® Simulink block diagram from the implementation point of view.The model was then validated using a single cell PEM electrolyser powered by a Hybrid Multi-source Platform (HMP) running on solar and wind energy at the University of Lille. The proposed model was also extended for the modelling and performance study of Anion Exchange Membrane (AEM) electrolysis cell, in collaboration with the University of Exeter of England, which shares a similar configuration and architecture.The developed model for the PEM electrolysis system is also suitable for the development of control, diagnosis, and prognosis algorithms. Therefore, a model-based robust fault diagnosis for PEM water electrolyser has been proposed in this work. The proposed diagnosis algorithms and model have been then utilized for developing the graphical user interface for online supervision
12
Nghe, Brandon K. "Cascaded Linear Regulator with Positive Voltage Tracking Switching Regulator." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2173.
Abstract:
This thesis presents the design, simulation, and hardware implementation of a proposed method for improving efficiency of voltage regulator. Typically, voltage regulator used for noise-sensitive and low-power applications involves the use of a linear regulator due to its high power-supply rejection ratio properties. However, the efficiency of a linear regulator depends heavily on the difference between its input voltage and output voltage. A larger voltage difference across the linear regulator results in higher losses. Therefore, reducing the voltage difference is the key in increasing regulator’s efficiency. In this thesis, a pre switching regulator stage with positive voltage tracking cascaded to a linear regulator is proposed to provide an input voltage to a linear regulator that is slightly above the output of the linear regulator. The tracking capability is needed to provide the flexibility in having different positive output voltage levels while maintaining high overall regulator’s efficiency. Results from simulation and hardware implementation of the proposed system showed efficiency improvement of up to 23% in cases where an adjustable output voltage is necessary. Load regulation performance of the proposed method was also overall better compared to the case without the output voltage tracking method.
13
Redgate, John. "Dynamic tracking of a cage induction motor operating at maximum efficiency in an electric vehicle." Thesis, Nottingham Trent University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436676.
14
Almgren, Björn. "Dynamic load modulation." Thesis, University of Gävle, Department of Technology and Built Environment, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-702.
Abstract:
The purpose of this master thesis was to study if the drain efficiency of power amplifiers can be maintained at power back off using a technique called load modulation.
The amplifier classes studied are E, F and D-1. The target figure was to obtain a 10 to 12 dB dynamic range of amplitude with reasonable efficiency. Studies of power amplifiers have been made to understand how power is generated. Several different load modulation networks have been evaluated. Attempts to derive design equations for the modulation networks have also been done.
The thesis work was carried out with simulations in ADS 2006. As active devices commercially available bare-die transistor models have been used. The power rating of the dies are 15 W.
A dynamic range of amplitude of over 15 dB has been achieved with drain efficiency greater than 60 percent. The peak output power is in the 40 – 45 dBm range.
15
Wang, Feipeng. "High efficiency linear envelope tracking and envelope elimination and restoration power amplifier for WLAN OFDM applications." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3238429.
Abstract:
Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed January 4, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 126-131).
16
Daswa, Khumbudzo Ashley. "Perfomance evaluation of the tracking ability and pricing efficiency of Exchange Traded Funds (ETFS) in South Africa." University of the Western cape, 2016. http://hdl.handle.net/11394/5562.
Abstract:
Magister Commercii - MComSince the listing of the Satrix 40 in November 2000, Exchange Traded Fund (ETFs) have grown to become an investment vehicle of choice amongst retail and institutional investors of the Johannesburg Securities Exchange (JSE). Albeit gaining such an enormous traction, investors' remains curious about ETFs ability to successfully replicate the movements of their target benchmark indices and also their capability to yield arbitrage profit opportunity through mispricing. In addition to that, investors are also interested to know whether ETFs as an index tracking investment vehicle are resilient in variously cycles of the economy. Motivated by this gap in the body of knowledge, this research undertakes to evaluate the tracking ability and pricing efficiency of 19 ETFs listed on the JSE over various cycles of the economy. According to Faulkner, Loewald and Makrelov (2013) South African economy experienced the effect of the 2008 global financial crisis between 1 September 2008 and 30 June 2009. For that reason, the examination period of this research is segmented into four main categories namely: full examination period which spans from the launch date of each of the ETF under review until 30 September 2015, pre-crisis period that is between the launch date and 29August 2008, crisis-period dated 1 September 2008 and 30 June 2009 and the post-crisis or the recovery phase being 1 July 2009 through 30 September 2015. The tracking ability results across all the sub-periods suggested that, on average, ETFs yields daily returns which closely resemble that of their target benchmark indices but with relatively high level of volatility. With regard to the tracking error as another tracking ability measurement, it was discovered that the ETFs under review were inadequately replicating the movements of their target benchmark indices irrespective of the economic cycle. In tandem with the evidence documented by Mateus and Rahmani (2014) from the London Stock Exchange (LSE), tracking errors were substantially high during the 2008 global financial crisis as opposed to the prior and the post crisis period. Across all the examination periods, sizeable amount of tracking error was found to be associated to the ETFs which mimics the international broad-market access underlying indices. Amongst other things, the diversity of these indices as well as the trading hours overlap between the JSE and their host market were found to be the key attributing factors. On the contrary, ETFs which replicates most liquid target benchmark indices such as the FTSE/JSE Top 40 index appeared to have lower tracking error on relative basis. In this regard, the liquidity of the FTSE/JSE Top 40 index proved to be the main attribute. Apart from the diversity or the liquidity of indices, the length of the examination period also had a significant influence towards the magnitude of tracking errors. In this instance, shorter examination period were found to be characterised by noise or volatility in the market which makes it difficult for the ETFs providers to promptly rebalance their portfolios and align them to their target benchmark indices. Over and above these factors, this research discovered that tracking errors across all the sub-periods were largely driven by management fees and daily volatility of the ETFs market prices, more especially during the crisis period. On the one hand, trading volume and the effect of dividends distribution had a negative influence towards the magnitude of tracking errors. On the question of how efficient these 19 ETFs are, the empirical findings revealed that significant deviation between the ETFs closing price and the Net Asset Value (NAV) does exist either being a discount or premium. In line with the prior work on the JSE by Charteris (2013), ETFs which mimics local based indices were found to be trading mostly on a discount to the NAV whilst the opposite was true in the case of the international broad-market access ETFs. At the same token, international broad-market access ETFs portrayed sizeable amount of premiums across all the cycles of the economy. In line with the analysis of tracking errors, such enormous premiums were mainly driven by lack of synchronicity in the trading hours between the JSE and host market wherein these ETFs target benchmark indices are listed. Empirical literature suggests that ETFs that exhibit discount and premium which fails to persist for more than one trading day are deemed to be efficiently priced since there is limited opportunity to arbitrage. On that note, this research found that mispricing of ETFs which mimics most liquid indices such as the domestic broad-market access and sectorial indices disappears within a period of one trading day. For that reason, majority of these ETFs were considered to be efficiently priced against their NAV. Contrarily, discounts and premiums exhibited by ETFs which mostly replicate style based and the international broad-market access indices appeared to be persistent even to the fifth trading day. From the attribution point of view, the complexity of these ETFs underlying indices as well as the trading hours overlap between the JSE and the host market of these indices were found to be the main drivers of such level of mispricing. In addition to that, attribution analysis through linear regression proved that transaction cost (bid-ask spread), daily volatility of the ETFs market prices as well as the impact of trading volume had a positive influence towards the existence of discounts and premiums observed across all sub-periods.
17
Choi, Sung In. "Smart Localized Heating Control System With Human Movement Tracking." Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/407171.
Abstract:
Electrical EngineeringM.S.E.E.
According to the U.S. energy consumption survey in 2012, about 25% of the commercial and 42% of the residential building energy were used for heating. Despite the development of new and more efficient Heating, Ventilation, and Air Conditioning (HVAC) systems over the years, the high energy consumption in heating is still one of the major energy efficiency issues. Studies showed that decreasing HVAC operating temperature set points by 4°F will result in energy savings of 15% or more. Thus, the smart localized heating control (SLHC) system was designed and prototyped to provide localized heat directly to a person so that HVAC can run at a lower temperature set point. SLHC detects human movement and delivers the heat based on the result of the target location estimation and temperature measurement feedback. To detect the human movement, image processing techniques were used; image segmentation, mass center detection, background subtraction using the Mixture of Gaussian model, and human feature detection. In SLHC, a near-infrared heater and a tracking function were used to provide an instant and a direct heat to the person in order to minimize wasting energy. The SLHC system is divided into the sensing and processing (SP) and the heating and regulating (HR) subsystem. The SP’s primary function is to process captured video images and measured temperature data. SP also generates and sends the heater operating signal to HR. HR purposes to control the heater’s direction and power based on the signal. The communication between SP and HR was established through Wi-Fi enabled development platform. The SLHC prototype successfully processed the sensing data and transmitted the control signal. The result shows that it detected human movement and estimated the person’s location in 3D space within 10% margin of error. Also, it delivered the focused heat to the surface of the human body and increased the temperature by 10.0°F in 3 minutes at the distance of 1.5m away from the heater. This cost-effective, wireless, and localized heating system demonstrates the potential to improve energy efficiency in buildings.
Temple University--Theses
18
Akhtar, Kareem. "A Numerical Study of Supersonic Rectangular Jet Impingement and Applications to Cold Spray Technology." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/71711.
Abstract:
Particle-laden supersonic jets impinging on a flat surface are of interest to cold gas-dynamic spray technology. Solid particles are propelled to a high velocity through a convergent-divergent nozzle, and upon impact on a substrate surface, they undergo plastic deformation and adhere to the surface. For given particle and substrate materials, particle velocity and temperature at impact are the primary parameters that determine the success of particle deposition. Depending on the particle diameter and density, interactions of particles with the turbulent supersonic jet and the compressed gas region near the substrate surface can have significant effects on particle velocity and temperature. Unlike previous numerical simulations of cold spray, in this dissertation we track solid particles in the instantaneous turbulent fluctuating flow field from the nozzle exit to the substrate surface. Thus, we capture the effects of particle-turbulence interactions on particle velocity and temperature at impact.
The flow field is obtained by direct numerical simulations of a supersonic rectangular particle-laden air jet impinging on a flat substrate. An Eulerian-Lagrangian approach with two-way coupling between solid particles and gas phase is used. Unsteady three-dimensional Navier-Stokes equations are solved using a six-order compact scheme with a tenth-order compact filter combined with WENO dissipation, almost everywhere except in a region around the bow shock where a fifth-order WENO scheme is used. A fourth-order low-storage Runge-Kutta scheme is used for time integration of gas dynamics equations simultaneously with solid particles equations of motion and energy equation for particle temperature. Particles are tracked in instantaneous turbulent jet flow rather than in a mean flow that is commonly used in the previous studies. Supersonic jets for air and helium at Mach number 2.5 and 2.8, respectively, are simulated for two cases for the standoff distance between the nozzle exit and the substrate. Flow structures, mean flow properties, particles impact velocity and particles deposition efficiency on a flat substrate surface are presented. Different grid resolutions are tested using 2, 4 and 8 million points. Good agreement between DNS results and experimental data is obtained for the pressure distribution on the wall and the maximum Mach number profile in wall jet. Probability density functions for particle velocity and temperature at impact are presented. Deposition efficiency for aluminum and copper particles of diameter in the range 1 micron to 40 microns is calculated.
Instantaneous flow fields for the two standoff distances considered exhibit different flow characteristics. For large standoff distance, the jet is unsteady and flaps both for air (Mach number 2.5) and for helium (Mach number 2.8), in the direction normal to the large cross-section of the jet. Linear stability analysis of the mean jet profile validates the oscillation frequency observed in the present numerical study. Available experimental data also validate oscillation frequency. After impingement, the flow re-expands from the compressed gas region into a supersonic wall jet. The pressure on the wall in the expansion region is locally lower than ambient pressure. Strong bow shock only occurs for small standoff distance. For large standoff distance multiple/oblique shocks are observed due to the flapping of the jet.
The one-dimensional model based on isentropic flow calculations produces reliable results for particle velocity and temperature. It is found that the low efficiency in the low-pressure cold spray (LPCS) compared to high-pressure cold spray (HPCS) is mainly due to low temperature of the particles at the exit of the nozzle. Three-dimensional simulations show that small particles are readily influenced by the large-scale turbulent structures developing on jet shear layers, and they drift sideways. However, large particles are less influenced by the turbulent flow. Particles velocity and temperature are affected by the compressed gas layer and remain fairly constant in the jet region. With a small increase in the particles initial temperature, the deposition efficiency in LPCS can be maximized. There is an optimum particle diameter range for maximum deposition efficiency.Ph. D.
19
Jiang, Bo. "Energy Efficient Target Tracking in Wireless Sensor Networks: Sleep Scheduling, Particle Filtering, and Constrained Flooding." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29963.
Abstract:
Energy efficiency is a critical feature of wireless sensor networks (WSNs), because sensor nodes run on batteries that are generally difficult to recharge once deployed. For target tracking---one of the most important WSN application types---energy efficiency needs to be considered in various forms and shapes, such as idle listening, trajectory estimation, and data propagation. In this dissertation, we study three correlated problems on energy efficient target tracking in WSNs: sleep scheduling, particle filtering, and constrained flooding.
We develop a Target Prediction and Sleep Scheduling protocol (TPSS) to improve energy efficiency for idle listening. We start with designing a target prediction method based on both kinematics and probability. Based on target prediction and proactive wake-up, TPSS precisely selects the nodes to awaken and reduces their active time, so as to enhance energy efficiency with limited tracking performance loss. In addition, we expand Sleep Scheduling to Multiple Target Tracking (SSMTT), and further reduce the energy consumption by leveraging the redundant alarm messages of interfering targets. Our simulation-based experimental studies show that compared to existing protocols such as Circle scheme and MCTA, TPSS and SSMTT introduce an improvement of 25% ~ 45% on energy efficiency, at the expense of only 5% ~ 15% increase on the detection delay.
Particle Filtering is one of the most widely used Bayesian estimation methods, when target tracking is considered as a dynamic state estimation problem for trajectory estimation. However, the significant computational and communication complexity prohibits its application in WSNs. We design two particle filters (PFs)---Vector space based Particle Filter (VPF) and Completely Distributed Particle Filter (CDPF)---to improve energy efficiency of PFs by reducing the number of particles and the communication cost. Our experimental evaluations show that even though VPF incurs 34% more estimation error than RPF, and CDPF incurs a similar estimation error to SDPF, they significantly improve the energy efficiency by as much as 68% and 90% respectively.
For data propagation, we present a Constrained Flooding protocol (CFlood) to enhance energy efficiency by increasing the deadline satisfaction ratio per unit energy consumption of time-sensitive packets. CFlood improves real-time performance by flooding, but effectively constrains energy consumption by controlling the scale of flooding---i.e., flooding only when necessary. If unicasting meets the distributed sub-deadline at a hop, CFlood aborts further flooding even after flooding has occurred in the current hop. Our simulation-based experimental studies show that CFlood achieves higher deadline satisfaction ratio per unit energy consumption by as much as 197%, 346%, and 20% than existing multipath forwarding protocols, namely, Mint Routing, MCMP and DFP respectively, especially in sparsely deployed or unreliable sensor network environments.
To verify the performance and efficiency of the dissertation's solutions, we developed a prototype implementation based on TelosB motes and TinyOS version 2.1.1. In the field experiments, we compared TPSS, VPF, CDPF, and CFlood algorithms/protocols to their respective competing efforts. Our implementation measurements not only verified the rationality and feasibility of the proposed solutions for target tracking in WSNs, but also strengthened the observations on their efficiency from the simulation.Ph. D.
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Haelssig, Jan B. "Improving the Energy Efficiency of Ethanol Separation through Process Synthesis and Simulation." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20100.
Abstract:
Worldwide demand for energy is increasing rapidly, partly driven by dramatic economic growth in developing countries. This growth has sparked concerns over the finite availability of fossil fuels and the impact of their combustion on climate change. Consequently, many recent research efforts have been devoted to the development of renewable fuels and sustainable energy systems. Interest in liquid biofuels, such as ethanol, has been particularly high because these fuels fit into the conventional infrastructure for the transportation sector.
Ethanol is a renewable fuel produced through the anaerobic fermentation of sugars obtained from biomass. However, the relatively high energy demand of its production process is a major factor limiting the usefulness of ethanol as a fuel. Due to the dilute nature of the fermentation product stream and the presence of the ethanol-water azeotrope, the separation processes currently used to recover anhydrous ethanol are particularly inefficient. In fact, the ethanol separation processes account for a large fraction of the total process energy demand.
In the conventional ethanol separation process, ethanol is recovered using several distillation steps combined with a dehydration process. In this dissertation, a new hybrid pervaporation-distillation system, named Membrane Dephlegmation, was proposed and investigated for use in ethanol recovery. In this process, countercurrent vapour-liquid contacting is carried out on the surface of a pervaporation membrane, leading to a combination of distillation and pervaporation effects. It was intended that this new process would lead to improved economics and energy efficiency for the entire ethanol production process.
The Membrane Dephlegmation process was investigated using both numerical and experimental techniques. Multiphase Computational Fluid Dynamics (CFD) was used to study vapour-liquid contacting behaviour in narrow channels and to estimate heat and mass transfer rates. Results from the CFD studies were incorporated into a simplified design model and the Membrane Dephlegmation process was studied numerically. The results indicated that the Membrane Dephlegmation process was more efficient than simple distillation and that the ethanol-water azeotrope could be broken. Subsequently, a pilot-scale experimental system was constructed using commercially available, hydrophilic NaA zeolite membranes. Results obtained from the experimental system confirmed the accuracy of the simulations.
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Joerger, Guillaume. "Multiscale modeling and event tracking wireless technologies to improve efficiency and safety of the surgical flow in an OR suite." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS009/document.
Abstract:
Améliorer la gestion et l’organisation des blocs opératoires est une tâche critique dans les hôpitaux modernes, principalement à cause de la diversité et l’urgence des activités impliquées. Contrairement à l’aviation civile, qui a su optimiser organisation et sécurité, le management de bloc opératoire est plus délicat. Le travail ici présenté abouti au développement et à l’installation de nouvelles technologies assistées par ordinateur résolvant les problèmes quotidiens des blocs opératoires. La plupart des systèmes existants modélisent le flux chirurgical et sont utilisés seulement pour planifier. Ils sont basés sur des procédés stochastiques, n’ayant pas accès à des données sûres. Nous proposons une structure utilisant un modèle multi-agent qui comprend tous les éléments indispensables à une gestion efficace et au maintien de la sécurité dans les blocs opératoires, allant des compétences communicationnelles du staff, au temps nécessaire à la mise en place du service de nettoyage. Nous pensons que la multiplicité des ressources humaines engagées dans cette structure cause des difficultés dans les blocs opératoires et doit être prise en compte dans le modèle. En parallèle, nous avons construit un modèle mathématique de flux d’air entre les blocs opératoires pour suivre et simuler la qualité de l’environnement de travail. Trois points sont nécessaires pour la construction et le bon fonctionnement d’un ensemble de bloc opératoire : 1) avoir accès au statut du système en temps réel grâce au placement de capteurs 2) la construction de modèles multi-échelles qui lient tous les éléments impliqués et leurs infrastructures 3) une analyse minutieuse de la population de patients, du comportement des employés et des conditions environnementales. Nous avons développé un système robuste et invisible qui permet le suivi et la détection automatique d’événements dans les blocs. Avec ce système nous pouvons suivre l’activité à la porte d’entrée des blocs, puis l’avancement en temps réel de la chirurgie et enfin l’état général du bloc. Un modèle de simulation numérique de mécanique des fluides de plusieurs blocs opératoires est utilisé pour suivre la dispersion de fumée chirurgicale toxique, ainsi qu’un modèle multi-domaine qui évalue les risques de propagation de maladie nosocomiale entre les blocs. La combinaison de ces trois aspects amène une nouvelle dimension de sensibilisation à l’environnent des blocs opératoires et donne au staff un système cyber-physique capable de prédire des événements rares impactant la qualité, l’efficacité, la rentabilité et la sécurité dans l’hôpitalImproving operating room management is a constant issue for modern large hospital systems who have to deal with the reality of day to day clinical activity. As opposed to other industrial sectors such as air civil aviation that have mastered the topic of industry organization and safety, progress in surgical flow management has been slower. The goal of the work presented here is to develop and implement technologies that leverage the principles of computational science to the application of OR suite problems. Most of the currently available models of surgical flow are used for planning purposes and are essentially stochastic processes due to uncertainties in the available data. We propose an agent-based model framework that can incorporate all the elements, from communication skills of the staff to the time it takes for the janitorial team to go clean an OR. We believe that human factor is at the center of the difficulty of OR suite management and should be incorporated in the model. In parallel, we use a numerical model of airflow at the OR suite level to monitor and simulate environment conditions inside the OR. We hypothesize that the following three key ingredients will provide the level of accuracy needed to improve OR management : 1) Real time updates of the model with ad hoc sensors of tasks/stages 2) Construction of a multi-scale model that links all key elements of the complex surgical infrastructure 3) Careful analysis of patient population factors, staff behavior, and environment conditions. We have developed a robust and non-obtrusive automatic event tracking system to make our model realistic to clinical conditions. Not only we track traffic through the door and the air quality inside the OR, we can also detect standard events in the surgical process. We propose a computational fluid dynamics model of a part of an OR suite to track dispersion of toxic surgical smoke and build in parallel a multidomain model of potential nosocomial contaminant particles flow in an OR suite. Combining the three models will raise the awareness of the OR suite by bringing to the surgical staff a cyber-physical system capable of prediction of rare events in the workflow and the safety conditions
22
Valenta, Artūras. "Vartotojo sąsajos efektyvumo įvertinimų tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130826_110233-41131.
Abstract:
Šiuo tyrimu siekiama išanalizuoti populiariausių vartotojo sąsajos tyrimų metodus ir įvertinti juos įvairiais aspektais bei nustatyti jų taikymo atvejus. Taip pat suprojektuoti eksperimentinę erdvę ir atlikti tyrimą su vienu iš vartotojo sąsajos tyrimo metodu. Išanalizuoti rezultatus ir juos palyginti su panašiu vartotojo sąsajos tyrimo metodu. Galiausiai ieškosime būdų pagerinti šio metodo tikslumui. Analizės metu buvo įvertinta 15 vartotojo sąsajos metodų. Remiantis žiniomis įgautomis atliekant literatūros analizę apie vartotojo sąsajos tyrimų atlikimo eigą ir vertinimo parametrus buvo atliktas eksperimentas, kurio tikslas ištirti pelės sekimo tikslumą lyginant su akių sekimo metodo tikslumu. Išaiškinus priežastis lemiančias pelės sekimo metodo tikslumą, jas pašalinome ir pakartojome eksperimentą. Atlikus eksperimentus paaiškėjo, kad pagrindinis veiksnys lemiantis pelės sekimo metodo tikslumą yra dalyvių pasyvumas, o dalyvius informavus apie pelės judinimo būtinybę kartu su akių judesiais, užfiksuotas šio metodo tikslumo padidėjimas iki 47% - 77%.In this research we are going to analyze most popular user interface research methods and evaluate them in different aspects and determinate their use of cases. In addition, create experimental space for one of the user interface methods research. Analyze results and compare with similar method. Lastly, we will look for solutions to increase its accuracy. 15 user interface research methods were evaluated in analyze stage. From gathered knowledge about user interface research methods and evaluation parameters, experiment was performed. His purpose was to evaluate mouse tracking accuracy as user interface method and compare it with eye tracking method. After causes for its accuracy were found, they were removed and repeated the experiment. After conducting the experiment we found out that the main factor in mouse tracking accuracy is user's inability to move mouse actively. After asking experiment participants to sync their eyes movement with mouse movements we witnessed 47% - 77% accuracy comparing with eye tracking method.
23
Brandon, Mathilde. "Optimisation conjointe de méthodes de linéarisation de l'émetteur pour des modulations multi-porteuses." Phd thesis, Université de Cergy Pontoise, 2012. http://tel.archives-ouvertes.fr/tel-00762747.
Abstract:
Les modulations multiporteuses apparaissent aujourd'hui comme une technologie éprouvée pour la transmission de données à haut-débits sur des canaux pouvant être très perturbés. L'OFDM (Orthogonal Frequency Division Multiplexing) a d'ailleurs été choisie dans plusieurs normes de télécommunications (ADSL, Wi-Max, IEEE 802.11a/g/n, LTE, DVB,...). Cependant un des inconvénients de ce type de modulation est la forte variation de la puissance instantanée à transmettre. Cette propriété rend ces modulations très sensibles aux non-linéarités des composants analogiques, en particulier celles de l'amplificateur de puissance à l'émission. Or l'amplificateur de puissance est un élément déterminant dans une chaîne de communication dans la mesure où il a une influence prépondérante sur le bilan global de la transmission en termes de puissance, de rendement et de distorsion. Plus l'on souhaite que l'impact de ses non linéarités soit faible et plus son rendement est faible, et inversement. Il est donc nécessaire d'effectuer un compromis linéarité/rendement.L'objectif de la thèse est d'éviter cette détérioration du rendement tout en conservant de bonnes performances de linéarité, de surcroit pour des signaux OFDM. Pour ce faire nous proposons d'utiliser conjointement des méthodes de linéarisation (prédistorsion numérique en bande de base) et d'amélioration du rendement (envelope tracking) de l'amplificateur de puissance ainsi qu'une méthode de réduction de la dynamique du signal (active constellation extension). La prédistorsion numérique classique échouant aux fortes puissances, nous proposons une méthode d'amélioration de cette technique à ces puissances. Nos résultats sont validés par des mesures sur un amplificateur de puissance 50W. Nous proposons également une association des méthodes permettant d'améliorer simultanément les performances en terme de linéarité hors bande et de rendement en minimisant les dégradations des performances de taux d'erreur binaire.
24
Cardoso, Pedro Miguel Martins. "Exchange-traded funds as an alternative investment option : evidence from the portuguese fund industry." Master's thesis, Instituto Superior de Economia e Gestão, 2017. http://hdl.handle.net/10400.5/14324.
Abstract:
Mestrado em Economia Monetária e FinanceiraUma análise comparativa da rentabilidade através de estatística descritiva, regressões e capacidade replicação do benchmark foi realizada para Exchange-traded Funds (ETFs), fundos de investimento de índices e de ações e o respetivo benchmark (PSI 20) para o período compreendido entre 2010 e 2015 para a indústria portuguesa de fundos de investimento. Para um horizonte temporal mais alargado (2010 - 2017), foi analisada a existência de diferenças (e a sua persistência) entre o preço do ETFs e o seu respetivo valor de unidade de participação (VUP). Concluiu-se que o ETF analisado não apresenta sempre uma melhor rentabilidade relativa (diferença entre a rentabilidade do fundo e do benchmark) por comparação com fundos de investimento de índice. Não obstante, o ETF exibe uma maior capacidade não só de replicar o benchmark quando este varia negativamente, como também de diminuir a volatilidade das diferenças entre a sua rentabilidade e a do benchmark. Ainda relativamente ao ETF, verifica-se que o mesmo se encontra, em termos médios, a negociar a um valor baixo de desconto (0,00007 €), existindo evidência de persistência destes desvios para pelos menos dois dias de negociação.
A comparative descriptive statistics, regression and index tracking return investigation between Exchange-traded Funds (ETFs), Index and Equity mutual funds and their respective benchmark during the 2010-2015 period is conducted for the Portuguese fund industry. For a larger interval (2010 - 2017), ETFs are tested for price inefficiency (existence of deviations between prices and the Net Asset Value) and its persistence. It is found that ETF do not always outperform index funds in replicating the variations of the PSI 20 index, despite exhibiting better tracking ability when facing downside deviations of the benchmark and a better capacity of smoothing tracking deviations. Regarding ETFs price efficiency and its persistence, the study reveals that the analyzed ETF is priced at a low average discount of €0.00007 with evidence of deviations persistence of at least two days.
info:eu-repo/semantics/publishedVersion
25
Ramírez, Eduardo Díaz. "A MORE EFFICIENT TRACKING SYSTEM FOR THE SANTIAGO SATELLITE TRACKING STATION." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604559.
Abstract:
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaA digital antenna control system has been designed and installed on a pedestal that was formerly used to drive a VHF array and that has now been replaced with an 11 meter S-Band parabolic reflector. In this Paper, the former analog tracking system will be described, showing all the drawbacks that made it unusable for S-Band. Subsequently, the development and implementation of the digital S-Band tracking system, using Labview, C++ & digital control theory will be discussed. Finally, there will be a comparison between the digital and analog system, too.
26
Ramos, Lucas Feksa. "Metodologia detalhada para rastreadores solares automatizados de dois eixos em sistemas fotovoltaicos." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/8593.
Abstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe search for diversity of energy sources in the world is one of the challenges that are driving research to fill this demand with alternative energy sources. So we have the need to explore alternative and renewable resources that bring flexibility and sustainability in its use. Presented before the panorama, the generation of electricity with solar photovoltaic systems is a trend, and has its technology constantly advancing, presenting itself as an immediate solution to this pursuit of diversity. The energy extracted from the Sun in photovoltaic generation systems depends on the flow of energy from the solar radiation in a plane perpendicular to the rays. Therefore, the average solar energy obtained by conventional solar panels during the course of the day, is not always maximized. One reason is that the fixed panels are not at an angle of zero degree zenith in relation to the Sun position. Thus, the movement East (E) to the West (W) daily, with the Earth's seasonal, directly affects the radiation intensity received by the photovoltaic panels. In this context, solar trackers can be used as devices that improve substantially the efficiency of photovoltaic panels, by letting them always perpendicular to the incident radiation received from the sun. In this dissertation demonstrates a methodology for automated solar tracking two axes for photovoltaic panels. The qualitative and quantitative results presented here show the real gain in power generation through the development of a real-time control algorithm for solar tracking systems of two axes, with their simulations and testing a low-cost prototype, developed in laboratory Center of Excellence in Energy and Power Systems (CEESP). Moreover, the results show that this methodology adapts successfully to the different conditions of use to track the sun's position, both in the laboratory and in the field.
A busca pela diversidade da matriz energética no mundo é um dos desafios que estão impulsionando pesquisas para preencher essa demanda com fontes de energia alternativa. Assim temos à necessidade de explorar recursos alternativos e renováveis que tragam flexibilidade e sustentabilidade quanto à sua utilização. Diante do panorama apresentado, a geração de energia elétrica com sistemas fotovoltaicos solares é uma tendência, e tem sua tecnologia em constante avanço, apresentando-se como uma solução imediata para essa busca da diversidade. A energia extraída do Sol em sistemas de geração fotovoltaicos depende do fluxo energético proveniente da radiação solar num plano perpendicular aos raios. Por isto, a energia solar média obtida pelos painéis solares convencionais durante o decorrer do dia, nem sempre é maximizada. Uma das causas é que os painéis fixos não estão com um ângulo de zênite de zero grau em relação à posição do Sol. Assim sendo, o movimento Leste (L) à Oeste (O) diário, junto ao sazonal da Terra, afeta diretamente a intensidade de radiação recebida pelos painéis fotovoltaicos. Neste contexto, os rastreadores solares podem ser usados como dispositivos que melhoram substancialmente à eficiência dos painéis fotovoltaicos, por deixálos sempre numa posição perpendicular à radiação incidente recebida do Sol. Nesta dissertação demonstra-se uma metodologia para rastreamento solar automatizado de dois eixos para painéis fotovoltaicos. Os resultados qualitativos e quantitativos aqui apresentados evidenciam o real ganho na geração de energia por meio do desenvolvimento de um algoritmo de controle em tempo real para sistemas de rastreamento solar de dois eixos, com as respectivas simulações e testes num protótipo de baixo custo, desenvolvido no laboratório do Centro de Excelência em Energia e Sistemas de Potência (CEESP). Além disso, os resultados evidenciam que esta metodologia se adapta com êxito às diferentes condições de uso para rastrear posições do sol, tanto em laboratório como no campo.
27
Chen, Zhexu (Zhexu Michael). "Efficient Multi-Target Tracking using graphical models." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45632.
Abstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 103-104).
The objective of this thesis is to develop a new framework for Multi-Target Tracking (MTT) algorithms that are distinguished by the use of statistical machine learning techniques. MTT is a crucial problem for many important practical applications such as military surveillance. Despite being a well-studied research problem, MTT remains challenging, mostly because of the challenges of computational complexity faced by current algorithms. Taking a very di®erent approach from any existing MTT algorithms, we use the formalism of graphical models to model the MTT problem according to its probabilistic structure, and subsequently develop e±cient, approximate message passing algorithms to solve the MTT problem. Our modeling approach is able to take into account issues such as false alarms and missed detections. Although exact inference is intractable in graphs with a mix of both discrete and continuous random variables, such as the ones for MTT, our message passing algorithms utilize e±cient particle reduction techniques to make approximate inference tractable on these graphs. Experimental results show that our approach, while maintaining acceptable tracking quality, leads to linear running time complexity with respect to the duration of the tracking window. Moreover, our results demonstrate that, with the graphical model structure, our approach can easily handle special situations, such as out-of-sequence observations and track stitching.
by Zhexu (Michael) Chen.
M.Eng.
28
Khairat, Saif. "Clinical content tracking system an efficient request tracking via a graphical user interface /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4892.
Abstract:
Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 28, 2008) Vita Includes bibliographical references.
29
Lee, Eun Ho. "Illumination, optics, and retroreflectors for efficient landmark tracking." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/15987.
30
Moutzouris, Alexandros. "Accurate human pose tracking using efficient manifold searching." Thesis, Kingston University, 2013. http://eprints.kingston.ac.uk/26599/.
Abstract:
In this thesis we propose novel methods for accurate markerless 3D pose tracking. Training data are used to represent specific activities, using dimensionality reduction methods. The proposed methods attempt to keep the computational cost low, without sacrificing the accuracy of the final result. Also, we deal with the problem of stylistic variation between the motions seen in the training and the testing dataset. Solutions to address both single and multiple action scenarios are presented. Specifically, appropriate temporal non-linear dimensionality reduction methods are applied to learn compact manifolds that are suitable for fast exploration. Such manifolds are efficiently searched by a deterministic gradient-based method. In order to deal with stylistic differences of human actions, we represent human poses using multiple levels. Searching through multiple levels reduces the effect of being trapped in a local optimal and therefore leads to higher accuracy. An observation function controls the process to minimise the computational cost of the method. Finally, we propose a multi-activity pose tracking methods, which combines action recognition with single-action pose tracking. To achieve reliable online action recognition, the system is equipped with short memory. All methods are tested in publicly available datasets. Results demonstrate their high accuracy and relative low computational cost, in comparison to state-of-the-art methods.
31
Hamilton, Christopher. "Digital control algorithms : low power wind turbine energy maximizer for charging lead acid batteries." Honors in the Major Thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1280.
Abstract:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Engineering and Computer Science
Electrical Engineering and Computer Science
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Yagoob, Muhammad Moeen. "Computationally efficient algorithms for non-linear target tracking problems." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499109.
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Zhao, Chuan. "Towards efficient surveillance using visual tracking and camera control." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526134.
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Rius, Ferrer Ignasi. "Motion Priors for Efficient Bayesian Tracking In Iluman Sequence Evaluation." Doctoral thesis, Universitat Autònoma de Barcelona, 2010. http://hdl.handle.net/10803/5798.
Abstract:
La reconstrucció del moviment huma mitjançant l'analisi visual és una area de recerca de la visió per computador plena de reptes amb moltes aplicacions potencials. Els enfocs de seguiment basat en models, i en particular els fltres de partícules, formulen el problema com una tasca d'inferencia Bayesiana l'objectiu de la qual és estimar seqüencialment la distribució sobre els parametres d'un model del cos huma al llarg del temps. Aquests enfocs depenen en gran mesuta d'emprar bons models dinamics i d'observació per tal de predir i actualitzar les confguracions del cos huma en base a mesures extretes de les dades d'imatge. No obstant, resulta molt difícil dissenyar models d'observació, i en especial pel cas de seguiment a partir d'una sola vista, que siguin capaços d'extreure informació útil de les seqüencies d'imatges de manera robusta. Per tant, per tal de superar aquestes limitacions és necessari emprar un fort coneixement a priori sobre el moviment huma i guiar així l'exploració de l'espai d'estats. El treball presentat en aquesta Tesis esta enfocat a recuperar els parametres de moviment 3D d'un model del cos huma a partir de mesures incompletes i sorolloses d'una seqüencia d'imatges monocular. Aquestes mesures consisteixen en les posicions 2D d'un conjunt redult d'articulacions en el pla d'imatge. Amb aquesta fnalitat, proposem un nou model de moviment huma específc per cada acció, que és entrenat a partir de bases de dades de captures de moviment que contenen varies execucions d'una acció en particular, i que és utilitzat com a coneixement a priori en un esquema de fltratge de partícules.
Les postures del cos es representen emprant un model articulat simple i compacte que fa ús dels cosinus directors per tal de representar la direcció de les parts del cos en l'espai Cartesia 3D. Llavors, donada una acció, s'aplica l'Analisis de Components Principals (PCA) sobre les dades d'entrenament per tal d'aplicar reducció de dimensionalitat sobre les dades d'entrada altament correlacionades. Previament al pas d'entrenament del model d'acció, les seqüencies de moviment d'entrada són sincronitzades mitjançant un nou algoritme d'adaptació dens basat en Programació Dinamica. L'algoritme sincronitza totes les seqüencies de moviment d'una mateixa classe d'acció i és capa¡ de trobar una solució óptima en temps real.
Aleshores, s'apren un model d'acció probabilístic a partir dels exemples de movi¬ment sincronitzats que captura la variabilitat i l'evolució temporal del moviment del cos sencer durant una acció concreta. En particular, per cada acció, els parametres apresos són: una varietat representativa de l'acció que consisteix en l'execució mitjana de la mateixa, la desviació estandard de l'execució mitjana, els vectors de direcció mitjans de cada subseqüencia de moviment d'una llargada donada i l'error esperat en un instant de temps donat.
A continuació, s'utilitza el model específc per cada acció com a coneixement a priori sobre moviment huma que millora l'efciencia i robustesa de tot l'enfoc de seguiment basat en fltratge de partícules. En primer lloc, el model dinamic guia les partícules segons situacions similars apreses previament. A continuació, es restringeix l'espai d'estats per tal que tan sols les postures humanes més factibles siguin acceptades com a solucions valides a cada instant de temps. En conseqüencia, l'espai d'estats és explorat de manera més efcient ja que el conjunt de partícules cobreix les postures del cos més probables.
Finalment, es duen a terme experiments emprant seqüencies de test de varies bases de dades. Els resultats assenyalen que el nostre esquema de seguiment és capa d'estimar la confguració 3D aproximada d'un model de cos sencer, a partir tan sols de les posicions 2D d'un conjunt redult d'articulacions. També s'inclouen proves separades sobre el metode de sincronització de seqüencies i de la tecnica de comparació probabilística de les subseqüencies de moviment.
Recovering human motion by visual analysis is a challenging computer vision research area with a lot of potential applications. Model based tracking approaches, and in particular particle flters, formulate the problem as a Bayesian inference task whose aim is to sequentially estimate the distribution of the parameters of a human body model over time. These approaches strongly rely on good dynamical and observation models to predict and update confgurations of the human body according to mea surements from the image data. However, it is very difcult to design observation models which extract useful and reliable information from image sequences robustly. This results specially challenging in monocular tracking given that only one viewpoint from the scene is available. Therefore, to overcome these limitations strong motion priors are needed to guide the exploration of the state space.
The work presented in this Thesis is aimed to retrieve the 3D motion parameters of a human body model from incomplete and noisy measurements of a monocular image sequence. These measurements consist of the 2D positions of a reduced set of joints in the image plane. Towards this end, we present a novel action specifc model of human motion which is trained from several databases of real motion captured performances of an action, and is used as a priori knowledge within a particle fltering scheme.
Body postures are represented by means of a simple and compact stick fgure model which uses direction cosines to represent the direction of body limbs in the 3D Cartesian space. Then, for a given action, Principal Component Analysis is applied to the training data to perform dimensionality reduction over the highly correlated input data. Before the learning stage of the action model, the input motion performances are synchronized by means of a novel dense matching algorithm based on Dynamic Programming. The algorithm synchronizes all the motion sequences of the same action class, fnding an optimal solution in real time.
Then, a probabilistic action model is learnt, based on the synchronized motion examples, which captures the variability and temporal evolution of full body motion within a specifc action. In particular, for each action, the parameters learnt are: a representative manifold for the action consisting of its mean performance, the stan dard deviation from the mean performance, the mean observed direction vectors from each motion subsequence of a given length and the expected error at a given time instant.
Subsequently, the action specifc model is used as a priori knowledge on human motion which improves the efciency and robustness of the overall particle fltering tracking framework. First, the dynamic model guides the particles according to similar situations previously learnt. Then, the state space is constrained so only feasible human postures are accepted as valid solutions at each time step. As a result, the state space is explored more efciently as the particle set covers the most probable body postures.
Finally, experiments are carried out using test sequences from several motion databases. Results point out that our tracker scheme is able to estimate the rough 3D confguration of a full body model providing only the 2D positions of a reduced set of joints. Separate tests on the sequence synchronization method and the subsequence probabilistic matching technique are also provided.
Keywords: Human Motion Modeling; Particle fltering; Monocular Full Body 3D Tracking.
Topics: Image Processing; Computer Vision; Scene Understanding; Machine Intelligence; Machine Vision Applications; Video-Sequence Evaluation
35
Zhou, Huiyu. "Efficient ego-motion tracking and obstacle detection using gait analysis." Thesis, Heriot-Watt University, 2006. http://hdl.handle.net/10399/141.
36
Han, Shin-Chan. "Efficient global gravity field determination from satellite-to-satellite tracking." Columbus, Ohio : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1061995200.
Abstract:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xvii, 198 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Christopher Jekeli, Dept. of Geodetic Science and Surveying. Includes bibliographical references (p. 192-198).
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Blasse, Corinna. "Towards Accurate and Efficient Cell Tracking During Fly Wing Development." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-214923.
Abstract:
Understanding the development, organization, and function of tissues is a central goal in developmental biology. With modern time-lapse microscopy, it is now possible to image entire tissues during development and thereby localize subcellular proteins. A particularly productive area of research is the study of single layer epithelial tissues, which can be simply described as a 2D manifold. For example, the apical band of cell adhesions in epithelial cell layers actually forms a 2D manifold within the tissue and provides a 2D outline of each cell. The Drosophila melanogaster wing has become an important model system, because its 2D cell organization has the potential to reveal mechanisms that create the final fly wing shape. Other examples include structures that naturally localize at the surface of the tissue, such as the ciliary components of planarians.
Data from these time-lapse movies typically consists of mosaics of overlapping 3D stacks. This is necessary because the surface of interest exceeds the field of view of todays microscopes. To quantify cellular tissue dynamics, these mosaics need to be processed in three main steps: (a) Extracting, correcting, and stitching individ- ual stacks into a single, seamless 2D projection per time point, (b) obtaining cell characteristics that occur at individual time points, and (c) determine cell dynamics over time. It is therefore necessary that the applied methods are capable of handling large amounts of data efficiently, while still producing accurate results. This task is made especially difficult by the low signal to noise ratios that are typical in live-cell imaging.
In this PhD thesis, I develop algorithms that cover all three processing tasks men- tioned above and apply them in the analysis of polarity and tissue dynamics in large epithelial cell layers, namely the Drosophila wing and the planarian epithelium. First, I introduce an efficient pipeline that preprocesses raw image mosaics. This pipeline accurately extracts the stained surface of interest from each raw image stack and projects it onto a single 2D plane. It then corrects uneven illumination, aligns all mosaic planes, and adjusts brightness and contrast before finally stitching the processed images together. This preprocessing does not only significantly reduce the data quantity, but also simplifies downstream data analyses. Here, I apply this pipeline to datasets of the developing fly wing as well as a planarian epithelium.
I additionally address the problem of determining cell polarities in chemically fixed samples of planarians. Here, I introduce a method that automatically estimates cell polarities by computing the orientation of rootlets in motile cilia. With this technique one can for the first time routinely measure and visualize how tissue polarities are established and maintained in entire planarian epithelia.
Finally, I analyze cell migration patterns in the entire developing wing tissue in Drosophila. At each time point, cells are segmented using a progressive merging ap- proach with merging criteria that take typical cell shape characteristics into account. The method enforces biologically relevant constraints to improve the quality of the resulting segmentations. For cases where a full cell tracking is desired, I introduce a pipeline using a tracking-by-assignment approach. This allows me to link cells over time while considering critical events such as cell divisions or cell death. This work presents a very accurate large-scale cell tracking pipeline and opens up many avenues for further study including several in-vivo perturbation experiments as well as biophysical modeling.
The methods introduced in this thesis are examples for computational pipelines that catalyze biological insights by enabling the quantification of tissue scale phenomena and dynamics. I provide not only detailed descriptions of the methods, but also show how they perform on concrete biological research projects.
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Mohammad, Shafiei Adel. "An Energy-Efficient Target Tracking Protocol Using Wireless Sensor Networks." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32384.
Abstract:
Target tracking using Wireless Sensor Networks (WSNs) has drawn lots of attentions
after the recent advances of wireless technologies. Target tracking aims at locating
one or several mobile objects and depicting their trajectories over time. The applications
of Object Tracking Sensor Networks (OSTNs) include but not limited to environmental
and wildlife monitoring, industrial sensing, intrusion detection, access control, traffic
monitoring, patient monitoring in the health-related studies and location awareness in
the battle eld. One of the most rewarding applications of target tracking is wildlife
monitoring. Wildlife monitoring is used to protect the animals which are endangered
to extinction. Road safety applications are another popular usage of wildlife monitoring
using WSNs.
In this thesis, the issues and challenges of energy-efficient wildlife monitoring and
target tracking using WSNs are discussed. This study provides a survey of the proposed
tracking algorithms and analyzes the advantages and disadvantages of these algorithms. Some of the tracking algorithms are proposed to increase the energy e ciency of the tracking algorithm and to prolong the network lifetime; while, other algorithms aim at improving the localization accuracy or decreasing the missing rate. Since improving the energy efficiency of the system provides more alive sensors over time to locate the target; it helps to decrease the missing rate as the network ages. Thus, this study proposes to adjust the sensing radius of the sensor nodes in real-time to decrease the sensing energy consumption and prolong the network lifetime.
The proposed VAriable Radius Sensor Activation (VARSA) mechanism for target
tracking using wireless sensor networks tackles the energy consumption issues due to
resource constraints of the WSNs. VARSA reduces the radio covered area of each sensor node to only cover the Area of Interest (AoI) which is the location of the target in tracking applications. Thus, VARSA aims at decreasing the sensing energy consumption which leads to encreasing the network life time. In addition, VARSA decreases the missing rate over time as it provides more alive sensors to detect the target compared to previous activation algorithms as the network ages. VARSA is compared to PRediction-based Activation (PRA) and Periodic PRediction-based Activation (PPRA) algorithms which are two of the most promising algorithms proposed for sensor activation. The simulation results show that VARSA outperforms PRA and PPRA. VARSA prolongs the lifetime of the network and decreases the missing rate of the target over time.
39
Solis, Montero Andres. "Efficient Feature Extraction for Shape Analysis, Object Detection and Tracking." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34830.
Abstract:
During the course of this thesis, two scenarios are considered. In the first one, we contribute to feature extraction algorithms. In the second one, we use features to improve object detection solutions and localization. The two scenarios give rise to into four thesis sub-goals. First, we present a new shape skeleton pruning algorithm based on contour approximation and the integer medial axis. The algorithm effectively removes unwanted branches, conserves the connectivity of the skeleton and respects the topological properties of the shape. The algorithm is robust to significant boundary noise and to rigid shape transformations. It is fast and easy to implement. While shape-based solutions via boundary and skeleton analysis are viable solutions to object detection, keypoint features are important for textured object detection. Therefore, we present a keypoint featurebased planar object detection framework for vision-based localization. We demonstrate that our framework is robust against illumination changes, perspective distortion, motion
blur, and occlusions. We increase robustness of the localization scheme in cluttered environments and decrease false detection of targets. We present an off-line target evaluation strategy and a scheme to improve pose. Third, we extend planar object detection to a real-time approach for 3D object detection using a mobile and uncalibrated camera. We develop our algorithm based on two novel naive Bayes classifiers for viewpoint and feature matching that improve performance and decrease memory usage. Our algorithm exploits the specific structure of various binary descriptors in order to boost feature matching by conserving descriptor properties. Our novel naive classifiers require a database with a small memory footprint because we only store efficiently encoded features. We improve the feature-indexing scheme to speed up the matching process creating a highly efficient database for objects. Finally, we present a model-free long-term tracking algorithm based on the Kernelized Correlation Filter. The proposed solution improves the correlation tracker based on precision, success, accuracy and robustness while increasing frame rates. We integrate adjustable Gaussian window and sparse features for robust scale estimation creating a better separation of the target and the background. Furthermore, we include fast descriptors and Fourier spectrum packed format to boost performance while decreasing the memory footprint. We compare our algorithm with state-of-the-art techniques to validate the results.
40
Guo, Jing-Ming, Cheng-Hsin Chang, Hua Lee, and Vincent Radzicki. "EFFICIENT ARTIFACT-FREE VIDEO SYNOPSIS FOR TARGET DETECTION AND TRACKING." International Foundation for Telemetering, 2017. http://hdl.handle.net/10150/626981.
Abstract:
Target detection and tracking is one of the most common applications of video systems. The requirement of processing time due to the computation complexity has been the most challenging element for these operations. To achieve computation efficiency, video synopsis is one of the most promising approaches. Video synopsis is a technique that focuses on the removal or reduction of spatial and temporal redundancies, while maintaining important activities in the original video. In this paper, a new video synopsis scheme is introduced. Major characteristics of this technique include efficient background subtraction, superior processing speed, and effective object comparison.
41
Ambardekar, Amol A. "Efficient vehicle tracking and classification for an automated traffic surveillance system." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1451111.
42
Kravaritis, Giorgos. "Stochastic Bayesian estimation using efficient particle filters for vehicle tracking applications." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/12112.
Abstract:
The central focus of our work is on designing particle filters which use more efficiently their particles by seeding them instate space areas with greater significance and/or by varying their number. We begin by introducing the auxiliary local linearization particle filter (ALLPF) whose importance sampling density brings together the auxiliary sequential importance resampling technique and the local linearization particle filter (LLPF). A simulation study assesses it suitability for tracking manoeuvring targets. We next incorporate the prediction mechanism of the LLPF within a multi-target algorithm. The proposed particle filter (A-MLLPF) performs simultaneously the functions of measurement-to-track assignment and particle prediction while employing an adaptive number of prediction particles. Compared to the equivalent standard multi-target particle filter, we show that the A-MLLPF performs better both in terms of tracking accuracy and measurement association. The remaining of the thesis is devoted to vehicle tracking which exploits information from the road map. We first focus on the variable-structure multiple model particle filter (VSMMPF) from the literature and we enhance it with a varying particle scheme for using adaptively fewer particles when the vehicle travels on the road. Simulation results show that the proposed variation results in a similar performance but with a significant decrease of the particle usage. We then incorporate a gating and a joint probabilistic data association logic into the VSMMPE and use the resulting algorithm (MGTPF) to track multiple vehicles. Simulations demonstrate the suitability of the MGTPF in the multiple vehicle environment and quantify the performance improvement compared to a standard particle filter with an analogous association logic. Returning to the single-vehicle tracking problem, we introduce lastly the variable mass particle filter (VMPF). The VMPF uses a varying number of particles which allocates efficiently to its propagation modes according to the modes’ likelihood and difficulty. For compensating for the resulting statistical irregularities, it assigns to the particles appropriate masses which scale their weights. Other novel features of the proposed algorithm include an on-road propagation mechanism which uses just one particle and a technique for dealing with random road departure angles. Simulation results demonstrate the improved efficiency of the VMPF, since it requires in general fewer particles than the VSMMPF for achieving a better estimation accuracy.
43
Saeed, Muhammad Jasim. "A novel energy efficient wireless sensor network framework for object tracking." Thesis, Manchester Metropolitan University, 2017. http://e-space.mmu.ac.uk/622094/.
Abstract:
Object tracking is a typical application of Wireless Sensor Networks (WSNs), which refers to the process of locating a moving object (or multiple objects) over time using a sensor network. Object tracking in WSNs can be a time consuming and resource hungry process due to factors, such as the amount of data generated or limited resources available to the sensor network. The traditional centralised approaches where a number of sensors transmit all information to a base station or a sink node, increase computation burden. More recently static or dynamic clustering approaches have been explored. Both clustering approaches suffer from certain problems, such as, large clusters, redundant data collection and excessive energy consumption. In addition, most existing object tracking algorithms mainly focus on tracking an object instead of predicting the destination of an object. To address the limitations of existing approaches, this thesis presents a novel framework for efficient object tracking using sensor networks. It consists of a Hierarchical Hybrid Clustering Mechanism (HHCM) with a Prediction-based Algorithm for Destinationestimation (PAD). The proposed framework can track the destination of the object without prior information of the objects movement, while providing significant reduction in energy consumption. The costs of computation and communication are also reduced by collecting the most relevant information and discarding irrelevant information at the initial stages of communication. The contributions of this thesis are: Firstly, a novel Prediction-based Algorithm for Destination-estimation (PAD) has been presented, that predicts the final destination of the object and the path that particular object will take to that destination. The principles of origin destination (OD) estimation have been adopted to create a set of trajectories that a particular object could follow. These paths are made up of a number of mini-clusters, formed for tracking the object, combined together. PAD also contains a Multi-level Recovery Mechanism (MRM) that recovers tracking if the object is lost. MRM minimises the number of nodes involved in the recovery process by initiating the process at local level and then expanding to add more nodes till the object is recovered. Secondly, a network architecture called Hierarchical Hybrid Clustering Mechanism (HHCM) has been developed, that forms dynamic mini-clusters within and across static clusters to reduce the number of nodes involved in the tracking process and to distribute the initial computational tasks amoung a larger number of mini-cluster heads. Lastly, building upon the HHCM to create a novel multi-hierarchy aggregation and next-step prediction mechanism to gather the most relevant data about the movement of the tracked object and its next-step location, a Kalman-filter based approach for prediction of next state of an object in order to increase accuracy has been proposed. In addition, a dynamic sampling mechanism has been devised to collect the most relevant data. Extensive simulations were carried out and results were compared with the existing approaches to prove that HHCM and PAD make significant improvements in energy conservation. To the best of my knowledge the framework developed in unique and novel, which can predicts the destination of the moving object without any prior historic knowledge of the moving object.
44
Krishnaswamy, Sriram. "On Computationally Efficient Frameworks For Data Association In Multi-Target Tracking." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574672274983947.
45
Zuo, Tianyu. "An Efficient Vision-Based Pedestrian Detection and Tracking System for ITS Applications." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31778.
Abstract:
In this thesis, a novel Pedestrian Protection System (PPS), composed of the Pedestrian Detection System (PDS) and the Pedestrian Tracking System (PTS), was proposed. The PPS is a supplementary application for the Advanced Driver Assistance System, which is used to avoid collisions between vehicles and pedestrians.
The Pedestrian Detection System (PDS) is used to detect pedestrians from near to
far ranges with the feature-classi er-based detection method (HOG + SVM). To achieve pedestrian detection from near to far ranges, a novel structure was proposed. The structure of our PDS consists of two cameras (called CS and CL separately). The CS is equipped with a short focal length lens to detect pedestrians in near-to-mid range; and, the CL is equipped with a long focal length lens to detect pedestrians in mid-to-far range. To accelerate the processing speed of pedestrian detection, the parallel computing capacity of GPU was utilized in the PDS. The synchronization algorithm is also introduced to synchronize the detection results of CS and CL. Based on the novel pedestrian detection structure, the detection process can reach a distance which is more than 130 meters away without decreasing detection accuracy. The detection range can be extended more than
100 meters without decreasing the processing speed of pedestrian detection. Afterwards, an algorithm to eliminate duplicate detection results is proposed to improve the detection accuracy.
The Pedestrian Tracking System (PTS) is applied following the Pedestrian Detection
System. The PTS is used to track the movement trajectory of pedestrians and to predict the future motion and movement direction. A C + + class (called pedestrianTracking class, which is short for PTC) was generated to operate the tracking process for every detected pedestrian. The Kalman lter is the main algorithm inside the PTC. During the operation of PPS, the nal detection results of each frame from PDS will be transmitted to the PTS to enable the tracking process. The new detection results will be used to update the existing tracking results in the PTS. Moreover, if there is a newly detected pedestrian, a new process will be generated to track the pedestrian in the PTS. Based on the tracking results in PTS, the movement trajectory of pedestrians can be obtained and their future motion and movement direction can be predicted. Two kinds of alerts are generated based on the predictions: warning alert and dangerous alert. These two alerts represent di erent situations; and, they will alert drivers to the upcoming situations. Based on the predictions and alerts, the collisions can be prevented e ectively. The safety
of pedestrians can be guaranteed.
46
Serhat, Gulhan. "Efficient Detection And Tracking Of Salient Regions For Visual Processing On Mobile Platforms." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611036/index.pdf.
Abstract:
Visual Attention is an interesting concept that constantly widens its application areas in the field of image processing and computer vision. The main idea of visual attention is to find the locations on the image that are visually attractive. In this thesis, the visually attractive regions are extracted and tracked in video sequences coming from the vision systems of mobile platforms. First, the salient regions are extracted in each frame and a feature vector is constructed for each one. Then Scale Invariant Feature Transform (SIFT) is applied only to the salient regions to extract more stable features. The tracking is achieved by matching the salient regions of consecutive frames by comparing their feature vectors. Then the SIFT points of salient regions are matched to calculate the shift values for the matched pairs. Limiting the SIFT application to only the salient regions results in significantly reduced computational cost. Moreover, the salient region detection procedure is also limited to the predetermined regions throughout the video sequence in order to increase the efficiency. In addition, the visual attention channels are limited to the most dominant features of the regions. Experimental results that compare the algorithm outputs with ground-truth data reveal that, the proposed algorithm has fine tracking performance together with acceptable computational cost. Promising results are obtained even with blurred video sequences typical of ground vehicles and robots and in an uncontrolled environment.
47
Driessen, Brian J. "Efficient numerical methods for obtaining and tracking minimum time trajectories of dynamical systems." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/17392.
48
Walpola, Malaka J. "Energy-Efficient Self-Organization of Wireless Acoustic Sensor Networks for Ground Target Tracking." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/129.
Abstract:
With the developments in computing and communication technologies, wireless sensor networks have become popular in wide range of application areas such as health, military, environment and habitant monitoring. Moreover, wireless acoustic sensor networks have been widely used for target tracking applications due to their passive nature, reliability and low cost. Traditionally, acoustic sensor arrays built in linear, circular or other regular shapes are used for tracking acoustic sources. The maintaining of relative geometry of the acoustic sensors in the array is vital for accurate target tracking, which greatly reduces the flexibility of the sensor network. To overcome this limitation, we propose using only a single acoustic sensor at each sensor node. This design greatly improves the flexibility of the sensor network and makes it possible to deploy the sensor network in remote or hostile regions through air-drop or other stealth approaches. Acoustic arrays are capable of performing the target localization or generating the bearing estimations on their own. However, with only a single acoustic sensor, the sensor nodes will not be able to generate such measurements. Thus, self-organization of sensor nodes into virtual arrays to perform the target localization is essential. We developed an energy-efficient and distributed self-organization algorithm for target tracking using wireless acoustic sensor networks. The major error sources of the localization process were studied, and an energy-aware node selection criterion was developed to minimize the target localization errors. Using this node selection criterion, the self-organization algorithm selects a near-optimal localization sensor group to minimize the target tracking errors. In addition, a message passing protocol was developed to implement the self-organization algorithm in a distributed manner. In order to achieve extended sensor network lifetime, energy conservation was incorporated into the self-organization algorithm by incorporating a sleep-wakeup management mechanism with a novel cross layer adaptive wakeup probability adjustment scheme. The simulation results confirm that the developed self-organization algorithm provides satisfactory target tracking performance. Moreover, the energy saving analysis confirms the effectiveness of the cross layer power management scheme in achieving extended sensor network lifetime without degrading the target tracking performance.
49
Al-Hajri, Muhannad Khaled. "Object Tracking Sensor Networks using Sequential Patterns in an Energy Efficient Prediction Technique." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28880.
Abstract:
Wireless Sensor Networks applications are attracting more and more research, especially in energy saving techniques/architectures which is the focal point of most researchers in this area. One of the most interesting applications of Wireless Sensor Networks is the Object Tracking Sensor Networks which are used mainly to track certain objects in a monitored area and to report its location to the application's users. This application is a major energy consumer among other Wireless Sensor Networks applications. There have been many techniques that assist in delivering the required data while maintaining a lower energy consumption than the early approaches. Our approach revolves around the ability to predict the objects' future movements in order to track it with the minimum number of sensor nodes, while keeping the other sensor nodes in the network in a sleep mode. Thus, achieving our goals while reducing significantly the network's energy consumption. The prediction technique used in our proposed solution is based on the inherited patterns of the objects' movements in the network and how to utilize data mining techniques, such as Sequential Patterns, in order to predict which sensor node the moving object will be heading next. We propose the Prediction-based Tracking technique using Sequential Patterns (PTSP), which is designed to achieve significant reductions in the energy dissipated by the OTSN network, while maintaining an acceptable missing rate levels. PTSP is tested against basic tracking techniques in order to determine the appropriateness of PTSP in various circumstances. We also test PTSP against some OTSN impacting factors, such as number of tracked objects, object speed, sampling duration and sampling frequency. We also test 3 different missing object recovery mechanisms implemented in PTSP to determine which is the most energy conservative. The experimental results had shown that PTSP outperformed all the other basic tracking techniques and contributed remarkable amounts of savings in terms of energy consumption of the entire network even through different circumstances.
50
Zhang, Minjia. "Efficient Runtime Support for Reliable and Scalable Parallelism." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469557197.