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1
Odom, Craig Allen. "Navigation solution for the Texas A&M autonomous ground vehicle." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4244.
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The need addressed in this thesis is to provide an Autonomous Ground Vehicle (AGV)
with accurate information regarding its position, velocity, and orientation. The system chosen to
meet these needs incorporates (1) a differential Global Positioning System, (2) an Inertial
Measurement Unit consisting of accelerometers and angular-rate sensors, and (3) a Kalman
Filter (KF) to fuse the sensor data. The obstacle avoidance software requires position and
orientation to build a global map of obstacles based on the returns of a scanning laser
rangefinder. The path control software requires position and velocity.
The development of the KF is the major contribution of this thesis. This technology can
either be purchased or developed, and, for educational and financial reasons, it was decided to
develop instead of purchasing the KF software. This thesis analyzes three different cases of
navigation: one-dimensional, two dimensional and three-dimensional (general). Each becomes
more complex, and separating them allows a three step progression to reach the general motion
solution.
Three tests were conducted at the Texas A&M University Riverside campus that
demonstrated the accuracy of the solution. Starting from a designated origin, the AGV traveled
along the runway and then returned to the same origin within 11 cm along the North axis, 19 cm
along the East axis and 8 cm along the Down axis. Also, the vehicle traveled along runway 35R
which runs North-South within 0.1ð, with the yaw solution consistently within 1ð of North or
South. The final test was mapping a box onto the origin of the global map, which requires
accurate linear and angular position estimates and a correct mapping transformation.
2
Stylianides, Theodoros. "Highway filter drains maintenance management." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/27533.
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Across a large part of the UK highways network the carriageway and pavement foundations are drained by Highway Filter Drains (HFDs). A HFD is a linear trench constructed either at the pavement edge or central reserve, fitted with a porous carrier pipe at the base and backfilled with an initially highly porous aggregate material. This arrangement enables the swift removal of surface runoff and subsurface water from the pavement system minimising road user hazards and eliminating risk of structural damage to the pavement sub-base. The highly porous backfill filters throughout its operational life fines washed from the pavement wearing course or adjacent land. HFDs have been found to be prone to collecting near the basal sections (pipe) or surface layers contaminants or detritus that causes the filter media to gradually block. The process has been defined as HFD clogging and it has been found to lead to reduced drainage capacity and potentially severe drop of serviceability. O&M contractual agreements for DBFO projects usually propose in-service and handback requirements for all assets included in the concession portfolio. Different performance thresholds are thus prescribed for pavements, structures, ancillary assets or street lighting. Similar definitions can be retrieved for drainage assets in such agreements, and these include HFDs. Performance metrics are defined though in a generic language and residual life (a key indicator for major assets that usually drives long-term maintenance planning) is prescribed without indicative means to evaluate such a parameter. Most of pavement maintenance is carried out nowadays using proactive management thinking and engineered assessment of benefits and costs of alternative strategies (what-if scenarios). Such a proactive regime is founded upon data driven processes and asset specific ageing / renewal understanding. Within the spectrum of road management, maintenance Life Cycle Costs are usually generated and updated on an annual basis using inventory and condition data linked to a Decision Support Tool (DST). This enables the assessment and optimisation of investment requirements and projection of deterioration and of treatment impacts aligned to continuous monitoring of asset performance. Following this paradigm shift in infrastructure management, a similar structured methodology to optimise HFD maintenance planning is desired and is introduced in this thesis. The work presented enables the identification of proactive maintenance drivers and potential routes in applying a systemised HFD appraisal and monitoring system. An evaluation of Asset Management prerequisites is thus discussed linked to an overview of strategic requirements to establish such a proactive approach. The thesis identifies condition assessment protocols and focuses on developing the means to evaluate deteriorated characteristics of in service drains using destructive and non-destructive techniques. A probabilistic HFD ageing / renewal model is also proposed using Markov chains. This builds upon existing deterioration understanding and links back to current treatment options and impacts. A filter drain decision support toolkit is lastly developed to support maintenance planning and strategy generation.
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Fakoorian, Seyed Abolfazl. "Ground Reaction Force Estimation in Prosthestic Legs with an Extended Kalman Filter." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu148227120124386.
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Sun, Yanshen. "Evaluating the quality of ground surfaces generated from Terrestrial Laser Scanning (TLS) data." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90577.
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Researchers and GIS analysts have used Aerial Laser Scanning (ALS) data to generate Digital Terrain Models (DTM) since the 1990s, and various algorithms developed for ground point extraction have been proposed based on the characteristics of ALS data. However, Terrestrial Laser Scanning (TLS) data, which might be a better indicator of ground morphological features under dense tree canopies and more accessible for small areas, have been long ignored. In this research, the aim was to evaluate if TLS data were as qualified as ALS to serve as a source of a DTM. To achieve this goal, there were three steps: acquiring and aligning ALS and TLS of the same region, applying ground filters on both of the data sets, and comparing the results.
Our research area was a 100m by 140m region of grass, weeds and small trees along Strouble's Creek on the Virginia Tech campus. Four popular ground filter tools (ArcGIS, LASTools, PDAL, MCC) were applied to both ALS and TLS data. The output ground point clouds were then compared with a DTM generated from ALS data of the same region. Among the four ground filter tools employed in this research, the distances from TLS ground points to the ALS ground surface were no more than 0.06m with standard deviations less than 0.3m. The results indicated that the differences between the ground extracted from TLS and that extracted from ALS were subtle. The conclusion is that Digital Terrain Models (DTM) generated from TLS data are valid.<br>Master of Science<br>Elevation is one of the most basic data for researches such as flood prediction and land planning in the field of geography, agriculture, forestry, etc. The most common elevation data that could be downloaded from the internet were acquired from field measurements or satellites. However, the finest grained of that kind of data is 1/3m and errors can be introduced by ground objects such as trees and buildings. To acquire more accurate and pure-ground elevation data (also called Digital Terrain Models (DTM)), Researchers and GIS analysts introduced laser scanners for small area geographical research. For land surface data collection, researchers usually fly a drone with laser scanner (ALS) to derive the data underneath, which could be blocked by ground objects. An alternative way is to place the laser scanner on a tripod on the ground (TLS), which provides more data for ground morphological features under dense tree canopies and better precision. As ALS and TLS collect data from different perspectives, the coverage of a ground area can be different. As most of the ground extraction algorithm were designed for ALS data, their performance on TLS data hasn’t been fully tested yet. Our research area was a 100m by 140m region of grass, weeds and small trees along Strouble’s Creek on the Virginia Tech campus. Four popular ground filter tools (ArcGIS, LASTools, PDAL, MCC) were applied to both ALS and TLS data. The output ground point clouds were then compared with a ground surface generated from ALS data of the same region. Among the four ground filter tools employed in this research, the distances from TLS ground points to the ALS ground surface were no more than 0.06m with standard deviations less than 0.3m. The results indicated that the differences between the ground extracted from TLS and that extracted from ALS were subtle. The conclusion is that Digital Terrain Models (DTM) generated from TLS data are valid.
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Burusa, Akshay Kumar. "Visual-Inertial Odometry for Autonomous Ground Vehicles." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217284.
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Monocular cameras are prominently used for estimating motion of Unmanned Aerial Vehicles. With growing interest in autonomous vehicle technology, the use of monocular cameras in ground vehicles is on the rise. This is especially favorable for localization in situations where Global Navigation Satellite System (GNSS) is unreliable, such as open-pit mining environments. However, most monocular camera based approaches suffer due to obscure scale information. Ground vehicles impose a greater difficulty due to high speeds and fast movements. This thesis aims to estimate the scale of monocular vision data by using an inertial sensor in addition to the camera. It is shown that the simultaneous estimation of pose and scale in autonomous ground vehicles is possible by the fusion of visual and inertial sensors in an Extended Kalman Filter (EKF) framework. However, the convergence of scale is sensitive to several factors including the initialization error. An accurate estimation of scale allows the accurate estimation of pose. This facilitates the localization of ground vehicles in the absence of GNSS, providing a reliable fall-back option.<br>Monokulära kameror används ofta vid rörelseestimering av obemannade flygande farkoster. Med det ökade intresset för autonoma fordon har även användningen av monokulära kameror i fordon ökat. Detta är fram för allt fördelaktigt i situationer där satellitnavigering (Global Navigation Satellite System (GNSS)) äropålitlig, exempelvis i dagbrott. De flesta system som använder sig av monokulära kameror har problem med att estimera skalan. Denna estimering blir ännu svårare på grund av ett fordons större hastigheter och snabbare rörelser. Syftet med detta exjobb är att försöka estimera skalan baserat på bild data från en monokulär kamera, genom att komplettera med data från tröghetssensorer. Det visas att simultan estimering av position och skala för ett fordon är möjligt genom fusion av bild- och tröghetsdata från sensorer med hjälp av ett utökat Kalmanfilter (EKF). Estimeringens konvergens beror på flera faktorer, inklusive initialiseringsfel. En noggrann estimering av skalan möjliggör också en noggrann estimering av positionen. Detta möjliggör lokalisering av fordon vid avsaknad av GNSS och erbjuder därmed en ökad redundans.
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Johnson, Hyrum David 1972. "Real-time identification for ground vehicle trajectory estimation using extended Kalman filter residual analysis." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80015.
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Green, Mark P. (Mark Peter) 1958. "Extended Kalman filter for integrating tracking data from ground-based radar and airborne global positioning system." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49627.
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Kirchhoff, Allan Richard. "Text Localization for Unmanned Ground Vehicles." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/52569.
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Unmanned ground vehicles (UGVs) are increasingly being used for civilian and military
applications. Passive sensing, such as visible cameras, are being used for navigation and object
detection. An additional object of interest in many environments is text. Text information can
supplement the autonomy of unmanned ground vehicles. Text most often appears in the
environment in the form of road signs and storefront signs. Road hazard information, unmapped
route detours and traffic information are available to human drivers through road signs. Premade
road maps lack these traffic details, but with text localization the vehicle could fill the
information gaps. Leading text localization algorithms achieve ~60% accuracy; however,
practical applications are cited to require at least 80% accuracy [49].
The goal of this thesis is to test existing text localization algorithms against challenging scenes,
identify the best candidate and optimize it for scenes a UGV would encounter. Promising text
localization methods were tested against a custom dataset created to best represent scenes a UGV
would encounter. The dataset includes road signs and storefront signs against complex
background. The methods tested were adaptive thresholding, the stroke filter and the stroke
width transform. A temporal tracking proof of concept was also tested. It tracked text through a
series of frames in order to reduce false positives.
Best results were obtained using the stroke width transform with temporal tracking which
achieved an accuracy of 79%. That level of performance approaches requirements for use in
practical applications. Without temporal tracking the stroke width transform yielded an accuracy
of 46%. The runtime was 8.9 seconds per image, which is 44.5 times slower than necessary for
real-time object tracking. Converting the MATLAB code to C++ and running the text
localization on a GPU could provide the necessary speedup<br>Master of Science
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Winkler, Joseph W. "An Investigation into Ground Moving Target Indication (GMTI) Using a Single-Channel Synthetic Aperture Radar (SAR)." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3555.
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Synthetic aperture radar (SAR) was originally designed as an airborne ground-imaging radar technology. But it has long been desired to also be able to use SAR imaging systems to detect, locate, and track moving ground targets, a process called Ground Moving Target Indication (GMTI). Unfortunately, due to the nature of how SAR works, it is inherently poorly suited to the task of GMTI. SAR only focuses targets and image features that remain stationary during the data collection. A moving ground target therefore does not focus in a conventional SAR image, which complicates the process of performing GMTI with SAR systems. This thesis investigates the feasibility of performing GMTI with single-channel, unsquinted, broadside stripmap SAR despite this inherent limitation. This study focuses solely on the idealized case of direct energy returns from point targets on flat ground, where they and the airborne radar platform all move rectilinearly with constant speed. First, the various aspects of how SAR works, the signal processing used to collect the SAR data, and the backprojection image formation algorithm are explained. The effects of target motion are described and illustrated in actual and simulated SAR images. It is shown how the backprojection (BPJ) algorithm, typically used to image a stationary landscape scene, can also focus on moving targets when the target motion is known a priori. A SAR BPJ ambiguity function is also derived and presented. Next, the time-changing geometry between the airborne radar and a ground target is mathematically analyzed, and it is shown that the slant range between the radar and any ground target, moving or stationary, is a hyperbolic function of time. It is then shown that this hyperbolic range history causes the single-channel SAR GMTI problem to be underdetermined. Finally, a method is then presented for resolving the underdetermined nature of the problem. This is done by constraining a target's GMTI solution using contextual information in the SAR image. Using constraining information, a theoretical way is presented to perform limited GMTI with a single-channel SAR system by using a modified form of the BPJ imaging algorithm, and practical considerations are addressed that complicate the process. Instead of focusing on stationary pixels, this GMTI method uses the BPJ ambiguity function to search for moving targets on a straight path, such as a road, by performing matched filtering on a collection of moving pixels in a position-velocity image space. Nevertheless, it is concluded that for moving point targets, general GMTI with no path constraints is infeasible in practice with a single-channel SAR.
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Himstedt, Marian. "Localization of autonomous ground vehicles in dense urban environments." Master's thesis, HTW Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:520-qucosa-126122.
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The localization of autonomous ground vehicles in dense urban environments poses a challenge.
Applications in classical outdoor robotics rely on the availability of GPS
systems in order to estimate the position. However, the presence of complex building structures in dense urban environments hampers a reliable localization based on GPS. Alternative approaches have to be applied In order to tackle this problem.
This thesis proposes an approach which combines observations of a single perspective camera and odometry in a probabilistic framework. In particular, the localization in the space of appearance is addressed. First, a topological map of reference places in the environment is built. Each reference place is associated with a set of visual features.
A feature selection is carried out in order to obtain distinctive reference
places. The topological map is extended to a hybrid representation by the use of metric information from Geographic Information Systems (GIS) and satellite images.
The localization is solved in terms of the recognition of reference places. A particle lter implementation incorporating this and the vehicle's odometry is presented.
The proposed system is evaluated based on multiple experiments in exemplary urban environments characterized by high building structures and a multitude of dynamic objects.
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Kolansky, Jeremy Joseph. "Real-Time Ground Vehicle Parameter Estimation and System Identification for Improved Stability Controllers." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/47351.
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Vehicle characteristics have a significant impact on handling, stability, and rollover propensity. This research is dedicated to furthering the research in and modeling of vehicle dynamics and parameter estimation.
Parameter estimation is a challenging problem. Many different elements play into the stability of a parameter estimation algorithm. The primary trade-off is robustness for accuracy. Lyapunov estimation techniques, for instance, guarantee stability but do not guarantee parameter accuracy. The ability to observe the states of the system, whether by sensors or observers is a key problem. This research significantly improves the Generalized Polynomial Chaos Extended Kalman Filter (gPC-EKF) for state-space systems. Here it is also expanded to parameter regression, where it shows excellent capabilities for estimating parameters in linear regression problems.
The modeling of ground vehicles has many challenges. Compounding the problems in the parameter estimation methods, the modeling of ground vehicles is very complex and contains many difficulties. Full multibody dynamics models may be able to accurately represent most of the dynamics of the suspension and vehicle body, but the computational time and required knowledge is too significant for real-time and realistic implementation. The literature is filled with different models to represent the dynamics of the ground vehicle, but these models were primarily designed for controller use or to simplify the understanding of the vehicle’s dynamics, and are not suitable for parameter estimation.
A model is devised that can be utilized for the parameter estimation. The parameters in the model are updated through the aforementioned gPC-EKF method as applies to polynomial systems. The mass and the horizontal center of gravity (CG) position of the vehicle are estimated to high accuracy.
The culmination of this work is the estimation of the normal forces at the tire contact patch. These forces are estimated through a mapping of the suspension kinematics in conjunction with the previously estimated vehicle parameters. A proof of concept study is shown, where the system is mapped and the forces are recreated and verified for several different scenarios and for changing vehicle mass.<br>Ph. D.
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Strange, Andrew Darren. "Robust thin layer coal thickness estimation using ground penetrating radar." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16356/.
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One of the most significant goals in coal mining technology research is the automation of underground coal mining machinery. A current challenge with automating underground coal mining machinery is measuring and maintaining a coal mining horizon. The coal mining horizon is the horizontal path the machinery follows through the undulating coal seam during the mining operation. A typical mining practice is to leave a thin remnant of coal unmined in order to maintain geological stability of the cutting face. If the remnant layer is too thick, resources are wasted as the unmined coal is permanently unrecoverable. If the remnant layer is too thin, the product is diluted by mining into the overburden and there is an increased risk of premature roof fall which increases danger. The main challenge therefore is to develop a robust sensing method to estimate the thickness of thin remant coal layers. This dissertation addresses this challenge by presenting a pattern recognition methodology to estimate thin remnant coal layer thickness using ground penetrating radar (GPR). The approach is based upon a novel feature vector, derived from the bispectrum, that is used to characterise the early-time segment of 1D GPR data. The early-time segment is dominated by clutter inherent in GPR systems such as antenna crosstalk, ringdown and ground-bounce. It is common practice to either time-gate the signal, disregard the clutter by rendering the early-time segment unusable, or configure the GPR equipment to minimise the clutter effects which in turn reduces probing range. Disregarding the early-time signal essentially imposes a lower thickness limit on traditional GPR layer thickness estimators. The challenges of estimating thin layer thickness is primarily due to these inherent clutter components. Traditional processing strategies attempt to minimise the clutter using pre-processing techniques such as the subtraction of a calibration signal. The proposed method, however, treats the clutter as a deterministic but unknown signal with additive noise. Hence the proposed approach utilises the energy from the clutter and monitors change in media from subtle changes in the signal shape. Two complementary processing methods important to horizon sensing have been also proposed. These methods, near-surface interface detection and antenna height estimation, may be used as pre-validation tools to increase the robustness of the thickness estimation technique. The proposed methods have been tested with synthetic data and validated with real data obtained using a low power 1.4 GHz GPR system and a testbed with known conditions. With the given test system, it is shown that the proposed thin layer thickness estimator and near-surface interface detector outperform the traditional matched filter based processing methods for layers less than 5 cm in thickness. It is also shown that the proposed antenna height estimator outperforms the traditional height estimator for heights less than 7 cm. These new methods provide a means for reliably extending layer thickness estimation to the thin layer case where traditional approaches are known to fail.
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Wyffels, Kevin L. "Development of a ground truth simulator and application of a generalized multiple-model adaptive estimation approach to tune a state estimation filter /." Online version of thesis, 2007. http://hdl.handle.net/1850/5280.
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Sharma, Rajnikant. "Bearing-Only Cooperative-Localization and Path-Planning of Ground and Aerial Robots." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2884.
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In this dissertation, we focus on two fundamental problems related to the navigation of ground robots and small Unmanned Aerial Vehicle (UAVs): cooperative localization and path planning. The theme running through in all of the work is the use of bearing only sensors, with a focus on monocular video cameras mounted on ground robots and UAVs. To begin with, we derive the conditions for the complete observability of the bearing-only cooperative localization problem. The key element of this analysis is the Relative Position Measurement Graph (RPMG). The nodes of an RPMG represent vehicle states and the edges represent bearing measurements between nodes. We show that graph theoretic properties like the connectivity and the existence of a path between two nodes can be used to explain the observability of the system. We obtain the maximum rank of the observability matrix without global information and derive conditions under which the maximum rank can be achieved. Furthermore, we show that for the complete observability, all of the nodes in the graph must have a path to at least two different landmarks of known location. The complete observability can also be obtained without landmarks if the RPMG is connected and at least one of the robots has a sensor which can measure its global pose, for example a GPS receiver. We validate these conditions by simulation and experimental results. The theoretical conditions to attain complete observability in a localization system is an important step towards reliable and efficient design of localization and path planning algorithms. With such conditions, a designer does not need to resort to exhaustive simulations and/or experimentation to verify whether a given selection of a control strategy, topology of the sensor network, and sensor measurements meets the observability requirements of the system. In turn, this leads to decreased requirements of time, cost, and effort for designing a localization algorithms. We use these observability conditions to develop a technique, for camera equipped UAVs, to cooperatively geo-localize a ground target in an urban terrain. We show that the bearing-only cooperative geo-localization technique overcomes the limitation of requiring a low-flying UAV to maintain line-of-sight while flying high enough to maintain GPS lock. We design a distributed path planning algorithm using receding horizon control that improves the localization accuracy of the target and of all of the UAVs while satisfying the observability conditions. Next, we use the observability analysis to explicitly design an active local path planning algorithm for UAVs. The algorithm minimizes the uncertainties in the time-to-collision (TTC) and bearing estimates while simultaneously avoiding obstacles. Using observability analysis we show that maximizing the observability and collision avoidance are complementary tasks. We provide sufficient conditions of the environment which maximizes the chances obstacle avoidance and UAV reaching the goal. Finally, we develop a reactive path planner for UAVs using sliding mode control such that it does not require range from the obstacle, and uses bearing to obstacle to avoid cylindrical obstacles and follow straight and curved walls. The reactive guidance strategy is fast, computationally inexpensive, and guarantees collision avoidance.
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Kufa, Martin. "Planární fraktální filtr na substrátu s porušenou zemí." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219832.
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The diploma thesis is focused on the design of planar filters combining fractal layouts and defected ground substrates. The diploma thesis can be divided into three main parts. First, basic knowledge about fractals is presented (creation of Minkowski Island and Koch loop, e.g.). Then, the principle of defected ground structure is described, and a combination of fractal motives with a defected ground structure is briefly introduced. Properties of investigated structures are verified by CST Microwave Studio and Ansoft HFSS. Second, different defected ground structures under the 50 transmission line are designed, and conventional equivalent filters are created. Filters are simulated and compared. In final, the investigated filters are recalculated for the substrate Arlon 25N, simulated, manufactured, measured and confronted with a conventional filter on the defected ground substrate.
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Vágner, Petr. "MIKROPÁSKOVÉ FILTRY S VYUŽITÍM NARUŠENÉ ZEMNÍ PLOCHY." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233479.
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The thesis deals with the microstrip filter design using defected ground structure (DGS). The difference between standard asymmetric microstrip technique and DGS is in using the structures etched in the microwave substrate ground plane. The DGS resonant characteristics are then used in filter design. The thesis consists of three factual parts. The first one (chapter 4) introduces the use of the DGS resonators in the lowpass filter design. It involves experimental analysis of one type of the lowpass filter. The second part (chapter 5) deals with a novel microstrip lowpass filter design method using DGS. The proposed method is verified by simulations and several samples are realized and measured. Finally, the third part (chapters 7 and 8) deals with the bandpass filter design using specific defected ground structure as a resonator. The resonators are used in a coupled resonator structure. Filters of various orders and resonator configurations are designed and simulated. A combination of the DGS resonators and half-wavelength microstrip resonators is introduced as well. Selected samples are realized and measurement results are compared with simulations.
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Frank, Ivo. "Čistírny odpadních vod v horských oblastech." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226904.
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Objectives of this master's thesis are to process review of technologies used to treat wastewater in alpine environment in Slovakia and in foreign countries. Thesis also includes mapping of situation of chosen alpine cottages in High Tatras. For cottages with unsuitable technology will be suggested more suitable solution.
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Bhattacharyya, Tumpa. "Filters on positive cones of lattice-ordered groups." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1304540043.
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Wei, Xiangmin. "GPR data processing for reinforced concrete bridge decks." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53066.
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In this thesis, several aspects of GPR data processing for RC bridge decks are studied. First, autofocusing techniques are proposed to replace the previous expensive and unreliable human visual inspections during the iterative migration process for the estimation of the velocity/dielectric permittivity distribution from GPR data. Second, F-K filtering with dip relaxation is proposed for interference removal that is important for both imaging and the performance of post-processing techniques including autofocusing techniques and CS-based migration studied in this thesis. The targeted interferes here are direct waves and cross rebar reflections. The introduced dip relaxation is for accommodating surface roughness and medium inhomogeneity. Third, the newly developed CS-based migration is modified and evaluated on GPR data from RC bridge decks. A more accurate model by accounting for impulse waveform distortion that leads to less modeling errors is proposed. The impact of the selection of the regularization parameter on the comparative amplitude reservation and the imaging performance is also investigated, and an approach to preserve the comparative amplitude information while still maintaining a clear image is proposed. Moreover, the potential of initially sampling the time-spatial data with uniform sampling rates lower than that required by traditional migration methods is evaluated.
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Annam, Kaushik. "Design of Bandstop Filters Using Defected Ground Structures." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1438420662.
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Hoff, Amanda. "High fidelity musician's filters and auditory figure-ground performance in children." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/a%5Fhoff%5F071906.pdf.
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Singh, Sachin. "Analysis of microstrip defected ground structure filters on anisotropic substrates using HFSS /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3209134.
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Thesis (Ph. D.)--University of Nevada, Reno, 2005.<br>"December 2005." Includes bibliographical references (leaves 213-220). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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Ting, Sio Weng. "Multiple-bandgap defected ground structure and its applications to highly selective microwave bandpass filters." Thesis, University of Macau, 2008. http://umaclib3.umac.mo/record=b2182957.
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Edman, Viktor. "Tracking Groups of People in Video Surveillance." Thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93996.
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In this master thesis, the problem of tracking groups using an image sequence dataset is examined. Target tracking can be defined as the problem of estimating a target's state given prior knowledge about its motion and some sensor measurements related to the target's state. A popular method for target tracking is e.g. the Kalman filter. However, the Kalman filter is insufficient when there are multiple targets in the scene. Consequently, alternative multitarget tracking methods must be applied along with methods for estimating the number of targets in the scene. Multitarget tracking can however be difficult when there are many unresolved targets, e.g. associating observations with targets in dense crowds. A viable simplification is group target tracking, keeping track of groups rather than individual targets. Furthermore, group target tracking is preferred when the user wants to know the motion and extension of a group in e.g. evacuation scenarios. To solve the problem of group target tracking in video surveillance, a combination of GM-PHD filtering and mean shift clustering is proposed. The GM-PHD filter is an approximation of Bayes multitarget filter. Pedestrian detections converted into flat world coordinates from the image dataset are used as input to the filter. The output of the GM-PHD filter consists of Gaussian mixture components with corresponding mean state vectors. The components are divided into groups by using mean shift clustering. An estimate of the number of members and group shape is presented for each group. The method is evaluated using both single camera measurements and two cameras partly surveilling the same area. The results are promising and present a nice visual representation of the groups' characteristics. However, using two cameras gives no improvement in performance, probably due to differences in detections between the two cameras, e.g. a single pedestrian can be observed being at two positions several meters apart making it difficult to determine if it is a single pedestrian or multiple pedestrians.
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Emilsson, Rasmus. "The influence of the Internet on Identity Creation and Extreme groups." Thesis, Blekinge Tekniska Högskola, Institutionen för teknik och estetik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-10372.
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In the age of the Internet, extreme groups have seen resurgence in the way they can communicate and recruit through the new medium whether they are white supremacists or hacktivists. Examining the history and modern behaviors of both white supremacy groups and Anonymous, this paper aims to research and answer how the different groups use the Internet to influence identities and if the methods to do so differ from the old ones and through the use of several concepts, mainly the Echo Chamber and the Filter Bubble, narrow down the effects that leads to a person joining an extreme group.
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Colgan, Gary A. "Estimating surface/ground-water mixing using stable environmental isotopes." Thesis, The University of Arizona, 1989. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0042_m_sip1_w.pdf&type=application/pdf.
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Vyskočil, Jiří. "Filtr na bázi vlnovodu integrovaného do substrátu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218850.
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In this thesis is discussed a filter design of a band-pass substrate integrated waveguide filter on the frequency of 5 GHz. It also includes design theory, filter synthesis, filter analysis in the program CST Microwave Studio® and the results of measurement on a vector network analyzer. The analysis results are compared with the measured results. Good agreement between simulated and measured results is observed.
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Yatheendradas, Soni. "Calibration of a distributed land surface model for a semi-arid basin using remotely sensed data." Thesis, The University of Arizona, 2003. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0052_m_sip1_w.pdf&type=application/pdf.
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Ptáček, Martin. "Studium ovlivnění hydratace portlandského cementu působením zinku." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401945.
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The topic of this work is the monitoring of the effect of zinc on the hydration process in Portland mixed cement (specifically with the addition of finely ground granulated blast-furnace slag, high temperature fly ash and fluidized bed combustion filter ash). How much zinc and at what time it remains in the pore solution during hydration. Activation energy of a mixture of cement with zinc in the form of soluble salts (Zn(NO3)2.6H2O and ZnCl2) and insoluble oxide (ZnO) by isothermal calorimetry was also investigated. The XRF method has shown composition during hydration. The zinc retardation effect was investigated by isothermal calorimetry and activation energy was calculated using this method. The XRF and ICP-OES methods were used to measure the zinc content of the pore solution. And the amount of portlandite was monitored by the DTA and XRF method.
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Chametzky, Barry. "Offsetting the Affective Filter| A Classic Grounded Theory Study of Post-Secondary Online Foreign Language Learners." Thesis, Northcentral University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3570240.
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<p>With the Internet, foreign language learners can interact more easily with native speakers from other countries than in previous generations. For learners to develop the ability to function in foreign environments, it is vital to understand their experiences in postsecondary online foreign language classes. If educators and educational theorists are not cognizant of the possible effects caused by using or not using technological tools, severe limitations will happen to relevant, cognitive connections. Because of the current lack of understanding, learners are at a sociological, cultural, cognitive, and psychological disadvantage. The purpose of this qualitative study using a classic grounded theory method was to discover a theory that described patterns of behaviors by 15 adult learners who took at least one post-secondary, online foreign language class from schools in the United States. This study revealed the concerns that learners had regarding their experiences and how they dealt with those issues. When learners struggled, they became frustrated thereby causing an imbalance that prevented them from accomplishing their desired objectives. Offsetting the affective filter, the theory developed in this study, is about (a) comprehending the causes for and consequences of learners' frustration and their elevated affective filters and (b) discovering various elements that helped learners restore balance and acquire the necessary knowledge. By taking online foreign language classes, learners stepped outside their comfort zones thus setting into motion an imbalance that needed to be offset. Because offsetting the affective filter has important ramifications with respect to cognition, more research is necessary to develop tools to help learners reduce their anxiety in online classes. By expanding the field of study to other online and hybrid subject areas, researchers could develop of a broader, formal grounded theory. Such research might lead to the redesigning of online classes to be more andragogic and more transformative while addressing the cognitive and affective needs of the learners. A redesigning of a course might be advanced due to the need for (a) increased synchronous interaction between course members, (b) increased humor to lower learners' anxiety levels, and (c) learning styles to be addressed via all four learning modalities. </p>
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Holden, Patrick W. "Pesticides and ground-water quality in four states issues and problems /." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_363_sip1_w.pdf&type=application/pdf.
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Colarullo, Susan J. "Identification of an optimal ground water management strategy in a contaminated aquifer." Thesis, The University of Arizona, 1988. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1988_602_sip1_w.pdf&type=application/pdf.
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Barlow, Paul M. "The use of temperature as a ground-water tracer in glacial outwash." Thesis, The University of Arizona, 1987. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1987_522_sip1_w.pdf&type=application/pdf.
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Korich, Dee Ann. "Ground Water Pollution Assessment of Landfills in the Rio Nuevo Area, Tucson, Arizona." Thesis, The University of Arizona, 2001. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0000_m_sip1_w.pdf&type=application/pdf.
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Lo, Haw-Jing. "Design of a reusable distributed arithmetic filter and its application to the affine projection algorithm." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28199.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Anderson, Dr. David V.; Committee Member: Hasler, Dr. Paul E.; Committee Member: Mooney, Dr. Vincent J.; Committee Member: Taylor, Dr. David G.; Committee Member: Vuduc, Dr. Richard.
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Herencsár, Norbert. "Nové aktivní funkční bloky a jejich aplikace v kmitočtových filtrech a kvadraturních oscilátorech." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-233510.
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Kmitočtové filtry a sinusoidní oscilátory jsou lineární elektronické obvody, které jsou používány v široké oblasti elektroniky a jsou základními stavebními bloky v analogovém zpracování signálu. V poslední dekádě pro tento účel bylo prezentováno velké množství stavebních funkčních bloků. V letech 2000 a 2006 na Ústavu telekomunikací, VUT v Brně byly definovány univerzální proudový konvejor (UCC) a univerzální napět'ový konvejor (UVC) a vyrobeny ve spolupráci s firmou AMI Semiconductor Czech, Ltd. Ovšem, stále existuje požadavek na vývoj nových aktivních prvků, které nabízejí nové výhody. Hlavní přínos práce proto spočívá v definici dalších původních aktivních stavebních bloků jako jsou differential-input buffered and transconductance amplifier (DBTA), current follower transconductance amplifier (CFTA), z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), generalized current follower differential input transconductance amplifier (GCFDITA), voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), a minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). Pomocí navržených aktivních stavebních bloků byly prezentovány původní zapojení fázovacích článků prvního řádu, univerzální filtry druhého řádu, ekvivalenty obvodu typu KHN, inverzní filtry, aktivní simulátory uzemněného induktoru a kvadraturní sinusoidní oscilátory pracující v proudovém, napět'ovém a smíšeném módu. Chování navržených obvodů byla ověřena simulací v prostředí SPICE a ve vybraných případech experimentálním měřením.
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Herndon, Roy Lee. "Hydrogeology of Butler Valley, Arizona an artificial recharge and ground-water storage prefeasibility study /." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_316_sip1_w.pdf&type=application/pdf.
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Boutejdar, Ahmed [Verfasser], Abbas [Akademischer Betreuer] Omar, and Edmund [Akademischer Betreuer] Burte. "Entwurf, Entwicklung und Optimierung von kompakten HF-Mikrostreifen-Filtern mittels "Defected Ground Structure"-Technik (DGS) / Ahmed Boutejdar. Betreuer: Abbas Omar ; Edmund Burte." Magdeburg : Universitätsbibliothek, 2011. http://d-nb.info/1047203006/34.
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Boutejdar, Ahmed Verfasser], Abbas [Akademischer Betreuer] [Omar, and Edmund [Akademischer Betreuer] Burte. "Entwurf, Entwicklung und Optimierung von kompakten HF-Mikrostreifen-Filtern mittels "Defected Ground Structure"-Technik (DGS) / Ahmed Boutejdar. Betreuer: Abbas Omar ; Edmund Burte." Magdeburg : Universitätsbibliothek, 2011. http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-122.
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Parmentier, Jean-Francois. "Extension du formalisme Euler/Euler pour la simulation des lits fluidisés de particules du groupe A dans la classification de Geldart." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0121/document.
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Ce travail a pour objectif d'améliorer la prédictivité des modèles à deux fluides pour la description des lits fluidisés gaz-solide pour les particules du groupe A dans la classification de Geldart. La première partie traite de l'incorporation de nouveaux phénomènes physiques dans le formalisme statistique utilisé : collisions induites par le cisaillement, phénomènes de lubrification lors des chocs et forces inter-particulaires. La deuxième partie traite de la résolution numérique du modèle. Il est montré que la simulation des lits de particules de type A présente une très forte sensibilité au maillage, conduisant à une surestimation de la hauteur du lit. L'introduction du formalisme filtré permet d'identifier la traînée filtrée comme étant l'origine principale du problème. Deux modèles de sous-maille sont proposés pour la prédiction de celle-ci et sont testés à la fois sur une configuration académique et sur une expérience de laboratoire<br>This work aims to increase the predictivity of the two-fluid model in gas-solid fluidized beds of Geldart A particles. The first part deals with the integration of physical phenomena into the two-fluid model: shear-induced collisions, lubrication between particles and inter-particular forces. The second part deals with the practical resolution of the two-fluid model using numerical codes. It is shown that bed expansion for Geldart A particles have a strong dependance on the mesh size used to compute the flow, leading to a major overestimation. The filtered approach is used and points up the filtered drag as the key of the problem. Two subgrid drag models are proposed and tested on both academic and laboratory configurations
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Le, Normand Jean-Pierre. "Les filtres actifs passe-tout micro-ondes en technologie MMIC : applications aux fonctions déphaseur et correcteur de temps de propagation de groupe." Brest, 1995. http://www.theses.fr/1995BRES2034.
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L'objet de notre travail consiste en l'etude, la conception et la realisation de structures actives passe-tout en hyperfrequences. Cette etude appartient au theme du filtrage et concerne la classe des filtres continus. Le developpement des filtres actifs hyperfrequences en technologie mmic a pour objectifs particuliers de reduire les dimensions, le poids et aussi le cout des filtres. L'ensemble de notre recherche sur les structures de fonction de transfert de type passe-tout et de leurs applications, est decompose en cinq grandes parties et rentre dans le cadre de l'action recherche et technologie du cnes concernant une etude prospective sur le filtrage actif micro-ondes, mettant a contribution cinq equipes de recherches. Dans un premier temps, nous rappelons rapidement dans le chapitre i quelques generalites sur les fonctions de transfert de filtrage et resumons le travail deja effectue dans le domaine du filtrage actif micro-ondes. Cette presentation nous permet en conclusion de situer notre travail et son contexte. Une theorie simplifiee detaillee dans le chapitre ii, n'utilisant que des elements ideaux, facilite l'analyse d'une structure active passe-tout realisee a l'aide de mesfet. La structure passe-tout peut etre configuree pour presenter une fonction de transfert bilineaire (premier ordre) ou biquadratique (second ordre). Nous developpons, a l'aide de ces deux configurations passe-tout, des applications en dephaseur commandable electroniquement et des applications en correcteur de temps de propagation de groupe. La conception de ces circuits nous conduit a presenter, au chapitre iii, la technologie mmic utilisee et a passer en revue les differents problemes lies a la conception de ces structures actives. Ensuite, une attention particuliere est portee au probleme de l'adaptation, probleme inherent au domaine micro-ondes. Nous presentons dans le chapitre iv la topologie electrique des trois circuits passe-tout. Les resultats de la simulation electrique sont ensuite donnes et suivis d'une analyse de sensibilite et de rendement. Puis, le dossier des masques est presente. Les resultats de simulation des circuits finaux, a partir des masques, sont directement compares aux mesures sous pointes effectuees sur les circuits realises. Le chapitre v est consacre aux resultats de mesures obtenus sur differentes maquettes fabriquees en technologie mic, qui utilisent les divers circuits mmic realises, afin de demontrer la possibilite de cascader les circuits dephaseurs et de demontrer la faisabilite de la fonction correcteur de temps de propagation de groupe
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Rucker, Dale Franklin. "Improved analysis of borehole ground penetrating radar to monitor transient water flow in the vadose zone." Diss., The University of Arizona, 2003. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2003_320_sip1_w.pdf&type=application/pdf.
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Župka, Jiří. "Orientace kamery v reálném čase." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237112.
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This work deals with the orientation of the camera in real-time with a single camera. Offline methods are described and used as a reference for comparison of a real-time metods. Metods work in real-time Monocular SLAM and PTAM methods are there described and compared. Further, paper shows hints of advanced methods whereas future work is possible.
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Chang, Yi-hau, and 張羿皓. "Defect Ground Structure (DGS) Bandstop Filter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/28403526066731914134.
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碩士<br>逢甲大學<br>電機工程所<br>95<br>A novel bandstop filter which utilized traditional defect ground structure filter and ring or loop patches is presented in this thesis.
The proposed filter can provide bandgap characteristic in some selective frequency band.
The proposed filter using a microstrip 50Ω fed line, and a slot defect on the ground plane. Then, utilizing either loop､ring､square or circle patches and changing the dimension of the patch to decrease the fundamental frequency, reduce the bandwidth and enhance the skirt effect.
Through the procedure, we have demonstrated the improved performance the proposed novel filter. Finally, a dumbbell patch isalso being implemented to change the fundamental frequency and harmonic frequency. A folder slot on the ground plane is also proposed and implemented successfully to achieve both performance enhancement miniaturization the filter.
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張祐誠. "Defected Ground Stucture Application for Micro-wave Filter Design." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/36995176682985118365.
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碩士<br>明新科技大學<br>電子工程研究所<br>94<br>Filter plays an important role in radio frequency front-end circuit of communication system. Regarding the communicatory receiver or transmitter for different frequency channel. We must insure that the integral data and there will not be influenced by other signals. For this reason, we have adopted different kind of filters to insulate the signals from other frequency channel. In the recent years, the mobile communications have developed rapidly, the trend of every devices of communicatory product are also more and more small. In order to be small frame, low cost, and easy to integrate with integrated circuit. In this thesis, we choose plane dual-mode band-pass filter to as be a basic structure. Its characteristic is to produce two transmission zeros, they could let stop-band attenuation faster on either side of the passband. But this structure also will produce harmonic. In order to reject harmonic, we introduced into defected ground structure（DGS）. Using the eliminated frequency characteristic to reject harmonic without increasing circuit size to become stop-band. Furthermore, we try to design a resonator structure on this circuit. Using this resonator structure to become another width passband to make a dual-band filter with defected ground structure.
We simulated best circuit design by simulation software IE3D and FR-4 substructure to complete the results between simulator and measurement. We can get a better performance such as simulator. This method is suitable function to reduce the filter size.
Keywords：filter、dual-mode、transmission zero、harmonic、defected ground structure
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Liu, Wei-Tsung, and 劉威宗. "A Novel Broadband Common-mode Filter Using Defected Ground Structure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/62528207855038733710.
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碩士<br>臺灣大學<br>電信工程學研究所<br>96<br>A novel common mode filter using periodic defected ground structure (PDGS) is proposed in this thesis. Unlike raditional common mode choke using ferrite material, this kind of common mode filter with high frequency and broadband common-mode noise suppression capability is embedded in inside printed circuit board without increasing any cost.
We focus on the study of the physical size parameters and characteristic behavior of the defected ground structure. The equivalent circuit model which is also proposed and presents good agreement whit the measurement result. In time domain analys is and measurement of the PDGS, the common mode noise due to the differential signal skew can be suppressed more than 60% for the propose filter. In EMI measurement, it is demonstrated this common mode filter can suppress common mode signal more than 10 dB within the stopband.
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Chang, Chun-Wei, and 張峻瑋. "Adaptive Filter and Ground Penetrating Radar for River Cross-Section." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/g32qtj.
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碩士<br>國立臺北科技大學<br>土木與防災研究所<br>99<br>The river cross-section is water management and quality one of the analytical important parameters. Traditional river cross section measurement needed to expend a great deal of manpower and time , the accuracy wasn''t high and not continuous. GPR used in a large number of engineering and geological exploration on Earth, In water table depth, fault location mining, embankments and other test items in the hollowed out very fruitful results.
The study area is Beishih basin Du nan bridge.The study establishes the ground-penetrating radar measurement and data analysis process. Use of adaptive noise cancellation analysis electromagnetic wave, effective when the GPR test facilities and generate sustained horizontal of signal noise and interference filter, establishes a adaptive filter parameter. Adaptive algorithm which uses Least-Mean-Square (LMS) and Recursive Least- Square (RLS); Characteristics of the GPR electromagnetic wave to establish sub-release mechanism, use Empirical Mode Decomposition (EMD) to improve the situation seabed information up and down oscillation, Available continuously river cross-section. Compare the differences of river cross section area with the traditional method, the river cross section area differences about 15% that’s a compare result. It’s proved using ground-penetrating radar can application for river cross section measurement.
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Wu, Hui-Wen, and 吳惠雯. "A Double U - Shaped Common Mode Filter On Defected Ground Structures." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/80418449513121598433.
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碩士<br>淡江大學<br>電機工程學系碩士在職專班<br>99<br>The asymmetric differential signals arrive at different times at the end, It will result in the generation of common mode noise. The common mode noise might result which might then cause timing margins and electromagnetic interference (EMI) problems.
The defected ground structures (DGS) might be utilized in all kinds of filter design. A new double U - shaped common-mode filter on defected ground structures can degrade common mode current and attenuation common mode insertion loss (SC2C1), but will not influence the differential mode insertion loss (SD2D1). The simulated results indicate that
the differential mode insertion loss is less than -3 dB and the common mode insertion loss is less than -3.3 dB (form 0 to 10 GHz). Show in the relevant literature, the insertion loss close to 0 dB, meaning that the entire signals is transmitted the insertion loss the smaller.
This is the double U - shaped common-mode filter advantage. It cans attenuation common mode noise, but will not influence the asymmetric differential signals is transmitted and lower costs.
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Kuo, Yong-Zhi, and 郭勇志. "The Design of Microstrip Line Filter Using the Defected Ground Structures." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/ndwye9.
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碩士<br>義守大學<br>電機工程學系<br>102<br>This thesis presents a kind of band reject effects, etching back of defect ground structure (DGS) on FR4 substrate, used in parallel coupled bandpass filter. Improve on defect from the odd mode and even mode phase velocities are mismatch generate harmonic passband in the (2f0) and (3f0) . In addition, we found three DGS to change their size and find the effect of operating frequency in different shapes.
Then we use the software of HFSS(High Frequency Structure Simulator) to design a parallel coupled bandpass filter in 2.5GHz of center frequency. The (2f0)5.02GHz and (3f0)7.32GHz appear on harmonic passband, by add DGS in parallel coupled bandpass filter. Finally, we take the FR4 substrate with DGS used in measurement and confirm defect ground structure can harmonic suppressions effectively, when attenuation take off to below -30dB.
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Lee, Yi-Hsien, and 李奕賢. "A Wideband Common-mode Suppression Filter Using Enhanced Coupled Defected Ground Structrue." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/875g65.
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碩士<br>國立臺北科技大學<br>電子工程系碩士班（碩士在職專班）<br>105<br>In this paper, we propose a wideband common-mode suppression filter for high-speed differential signals. The proposed design is realized by using only two enhanced coupled C-shaped defected ground structures (DGSs) with a long bridge to achieve the wideband common-mode noise suppression. The equivalent circuit model of two coupled LC resonators is also established with good agreement to the full-wave simulation and measurement results. A sample board is designed and fabricated on a printed circuit board (PCB) with FR4 substrate. It is proved that the differential-mode insertion loss is within -3 dB from DC to 12 GHz. Common-mode noise can be reduced over 10 dB from 3.7 GHz to 10.8 GHz in the frequency domain, and approximately 42% of amplitude in the time domain. Moreover, the fractional bandwidth of the stopband can reach 98%, and the filter size is only 0.3 λg × 0.3 λg, where λg is the wavelength of the stopband central frequency. To our knowledge, this is the first common-mode filter using an enhanced coupled mechanism for the high-speed signals to extend the stopband, and it is also a simple geometric structure with the largest fractional bandwidth and the most compact size on a PCB.