Dissertations / Theses on the topic 'Distributed tracking'
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Katragadda, Sandeep. "Distributed target tracking in wireless camera networks." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25899.
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Distributed target tracking (DTT) is desirable in wireless camera networks to achieve scalability and robustness to node or link failures. DTT estimates the target state via information exchange and fusion among cameras. This thesis proposes new DTT algorithms to handle five major challenges of DTT in wireless camera networks, namely non-linearity in the camera measurement model, temporary lack of measurements (benightedness) due to limited field of view, redundant information in the network, limited connectivity of the network due to limited communication ranges and asynchronous information caused by varying and unknown frame processing delays. The algorithms consist of two phases, namely estimation and fusion. In the estimation phase, the cameras process their captured frames, detect the target, and estimate the target state (location and velocity) and its uncertainty using the Extended Information Filter (EIF) that handles non-linearity. In the fusion phase, the cameras exchange their local target information with their communicative neighbours and fuse the information. The contributions of this thesis are as follows. The target states estimated by the EIFs undergo weighted fusion. The weights are chosen based on the estimated uncertainty (error covariance) and the number of nodes with redundant information such that the information of benighted nodes and the redundant information get lower weights. At each time step, only the cameras having the view of the target and the cameras that might have the view of the target in the next time step participate in the fusion (tracking). This reduces the energy consumption of the network. The algorithm selects the cameras dynamically by using a threshold on their shortest distances (in the communication graph) from the cameras having the view of the target. Before fusion, each camera predicts the target information of other cameras to temporally align its information with the (asynchronous) information received from other cameras. The algorithm predicts the target state using the latest estimated velocity of the target. The experimental results show that the proposed algorithms achieve higher tracking accuracy than the state of the art under the five DTT challenges.
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Sitta, Alessandro. "Privacy-Preserving Distributed Optimization via Obfuscated Gradient Tracking." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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As the modern world becomes increasingly digitized and interconnected, distributed systems have proven to be effective in the processing of large volumes of data. In this context, optimization techniques have become essential in an extensive range of domains. However, a major concern, regarding the privacy issue in handling sensitive data, has recently emerged.
To address this privacy issue we propose a novel consensus-based privacy-preserving distributed optimization algorithm called Obfuscated Gradient Tracking. The algorithm is characterized by a balanced noise insertion method which protects private data from being revealed to others, while not affecting the result’s accuracy. Indeed, we theoretically prove that the introduced perturbations do not condition the convergence properties of the algorithm, which is proven to reach the optimal solution without compromises. Moreover, security against the widely-used honest-but-curious adversary model, is shown. Furthermore, numerical tests are performed to show the effectiveness of the novel algorithm, both in terms of privacy and convergence properties. Numerical results highlight the Obfuscated Gradient Tracking attractiveness, against standard distributed algorithms, when privacy issues are involved. Finally, we present a privacy-preserving distributed Deep Learning application developed using our novel algorithm, with the aim of demonstrating its general applicability.
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Ali, Andreas Mantik. "Distributed acoustic localization and tracking design and analysis." Diss., Restricted to subscribing institutions, 2010. http://proquest.umi.com/pqdweb?did=2023768071&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Ing, Garrick. "Distributed particle filters for object tracking in sensor networks." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98971.
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A particle filter (PF) is a simulation-based algorithm used to solve estimation problems, such as object tracking. The PF works by maintaining a set of "particles" as candidate state descriptions of an object's position. The filter determines how well the set of particles describe the observations and fit the dynamic model, in order to form an object state estimate. The drawback of the basic PF is that the algorithm functions by collecting all data at a fusion centre. This leads to high communication and energy costs in a resource-limited network such as the sensor network. In this thesis, we analyze the PF to determine how it can be modified for efficient use in a sensor network. Our main priority is to keep communication and energy costs low since this increases the network lifetime. We propose two innovative particle filtering algorithms which minimizes the associated costs.
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Hoefener, Carl E. "DISTRIBUTED INTERACTIVE SIMULATION PROVEN IN FLIGHT TEST AIRCRAFT TRACKING." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/608558.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaWith the decline in military budgets worldwide, the need for ever more effective training is becoming apparent. The size of the armed forces is being reduced, so the remaining members have to be trained to be more effective and efficient in doing their jobs. To improve effectiveness and efficiency of performance, military training needs will be increased. Our largest training costs will be in pilot training because of the high cost of keeping aircraft in the air. When we look at the cost of training a pilot to operate in a multiplayer scenario against a large number of unfriendly aircraft and a large number of ground threats, the cost of training is tremendous. It requires a large number of personnel, aircraft and ground equipment to train a limited number of pilots. Our current Red Flag exercises can require as many as 75 aircraft in the air simultaneously plus a large number of ground threats and a large number of support personnel. This can amount to a prohibitive cost to train a limited number of pilots.
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Dias, Stiven Schwanz. "Collaborative emitter tracking using distributed sequential Monte Carlo methods." Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3137.
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We introduce in this Thesis several particle filter (PF) solutions to the problem of collaborative emitter tracking. In the studied scenario, multiple agents with sensing, processing and communication capabilities passively collect received-signal-strength (RSS) measurements of the same signal originating from a non-cooperative emitter and collaborate to estimate its hidden state. Assuming unknown sensor noise variances, we derive an exact decentralized implementation of the optimal centralized PF solution for this problem in a fully connected network. Next, assuming local internode communication only, we derive two fully distributed consensus-based solutions to the problem using respectively average consensus iterations and a novel ordered minimum consensus approach which allow us to reproduce the exact centralized solution in a finite number of consensus iterations. In the sequel, to reduce the communication cost, we derive a suboptimal tracker which employs suitable parametric approximations to summarize messages that are broadcast over the network. Moreover, to further reduce communication and processing requirements, we introduce a non-iterative tracker based on random information dissemination which is suited for online applications. We derive the proposed random exchange diffusion PF (ReDif-PF) assuming both that observation model parameters are perfectly known and that the emitter is always present. We extend then the ReDif-PF tracker to operate in scenarios with unknown sensor noise variances and propose the Rao-Blackwellized (RB) ReDif-PF. Finally, we introduce the random exchange diffusion Bernoulli filter (RndEx-BF) which enables the network of collaborative RSS sensors to jointly detect and track the emitter within the surveillance space.
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Srinivasan, Sabeshan. "Object Tracking in Distributed Video Networks Using Multi-Dimentional Signatures." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/SrinivasanSX2006.pdf.
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Nguyen, Trang. "Comparison of Sampling-Based Algorithms for Multisensor Distributed Target Tracking." ScholarWorks@UNO, 2003. http://scholarworks.uno.edu/td/20.
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Nonlinear filtering is certainly very important in estimation since most real-world problems are nonlinear. Recently a considerable progress in the nonlinear filtering theory has been made in the area of the sampling-based methods, including both random (Monte Carlo) and deterministic (quasi-Monte Carlo) sampling, and their combination. This work considers the problem of tracking a maneuvering target in a multisensor environment. A novel scheme for distributed tracking is employed that utilizes a nonlinear target model and estimates from local (sensor-based) estimators. The resulting estimation problem is highly nonlinear and thus quite challenging. In order to evaluate the performance capabilities of the architecture considered, advanced sampling-based nonlinear filters are implemented: particle filter (PF), unscented Kalman filter (UKF), and unscented particle filter (UPF). Results from extensive Monte Carlo simulations using different configurations of these algorithms are obtained to compare their effectiveness for solving the distributed target tracking problem.
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Krout, David Wayne. "Intelligent ping sequencing for multiple target tracking in distributed sensor fields /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6045.
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Thull, Daniel [Verfasser]. "Tracking Control of Mechanical Distributed Parameter Systems with Applications / Daniel Thull." Aachen : Shaker, 2010. http://d-nb.info/112086397X/34.
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David, Radu Alin. "Improving Channel Estimation and Tracking Performance in Distributed MIMO Communication Systems." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/229.
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This dissertation develops and analyzes several techniques for improving channel estimation and tracking performance in distributed multi-input multi-output (D-MIMO) wireless communication systems. D-MIMO communication systems have been studied for the last decade and are known to offer the benefits of antenna arrays, e.g., improved range and data rates, to systems of single-antenna devices. D-MIMO communication systems are considered a promising technology for future wireless standards including advanced cellular communication systems. This dissertation considers problems related to channel estimation and tracking in D-MIMO communication systems and is focused on three related topics: (i) characterizing oscillator stability for nodes in D-MIMO systems, (ii) the development of an optimal unified tracking framework and a performance comparison to previously considered sub-optimal tracking approaches, and (iii) incorporating independent kinematics into dynamic channel models and using accelerometers to improve channel tracking performance. A key challenge of D-MIMO systems is estimating and tracking the time-varying channels present between each pair of nodes in the system. Even if the propagation channel between a pair of nodes is time-invariant, the independent local oscillators in each node cause the carrier phases and frequencies and the effective channels between the nodes to have random time-varying phase offsets. The first part of this dissertation considers the problem of characterizing the stability parameters of the oscillators used as references for the transmitted waveforms. Having good estimates of these parameters is critical to facilitate optimal tracking of the phase and frequency offsets. We develop a new method for estimating these oscillator stability parameters based on Allan deviation measurements and compare this method to several previously developed parameter estimation techniques based on innovation covariance whitening. The Allan deviation method is validated with both simulations and experimental data from low-precision and high-precision oscillators. The second part of this dissertation considers a D-MIMO scenario with $N_t$ transmitters and $N_r$ receivers. While there are $N_t imes N_r$ node-to-node pairwise channels in such a system, there are only $N_t + N_r$ independent oscillators. We develop a new unified tracking model where one Kalman filter jointly tracks all of the pairwise channels and compare the performance of unified tracking to previously developed suboptimal local tracking approaches where the channels are not jointly tracked. Numerical results show that unified tracking tends to provide similar beamforming performance to local tracking but can provide significantly better nullforming performance in some scenarios. The third part of this dissertation considers a scenario where the transmit nodes in a D-MIMO system have independent kinematics. In general, this makes the channel tracking problem more difficult since the independent kinematics make the D-MIMO channels less predictable. We develop dynamics models which incorporate the effects of acceleration on oscillator frequency and displacement on propagation time. The tracking performance of a system with conventional feedback is compared to a system with conventional feedback and local accelerometer measurements. Numerical results show that the tracking performance is significantly improved with local accelerometer measurements.
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Pham, Tien. "Distributed source localization and tracking algorithms for ad-hoc acoustic sensor networks." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3539.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Carnevale, Guido. "Control-based Design and Analysis of Gradient-Tracking Algorithms for Distributed Quadratic Optimization." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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In this work we design an iterative distributed optimization algorithm, based on the well-known distributed gradient tracking algorithm. We show the advantages of a system theoretical approach on a distributed optimization framework in which the cost function is
given by a sum of quadratic functions. In other words, the main idea of the work consists in seeing the update equation characterizing an iterative optimization algorithm as the dynamics equation of a discrete-time system in which the decision variable plays the state
variable role. The goal of the work is to show how system and control theory tools can be used to force this state variable to the optimum of the considered cost function even in presence of disturbances and/or uncertainties. So, the design of a distributed optimization algorithm is seen as the design of a controller able to solve the set point control problem in which the reference signal is given by the optimum of the considered cost function.
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Palaniappan, Ravishankar. "A SELF-ORGANIZING HYBRID SENSOR SYSTEM WITH DISTRIBUTED DATA FUSION FOR INTRUDER TRACKING AND SURVEILLANCE." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2407.
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A wireless sensor network is a network of distributed nodes each equipped with its own sensors, computational resources and transceivers. These sensors are designed to be able to sense specific phenomenon over a large geographic area and communicate this information to the user. Most sensor networks are designed to be stand-alone systems that can operate without user intervention for long periods of time. While the use of wireless sensor networks have been demonstrated in various military and commercial applications, their full potential has not been realized primarily due to the lack of efficient methods to self organize and cover the entire area of interest. Techniques currently available focus solely on homogeneous wireless sensor networks either in terms of static networks or mobile networks and suffers from device specific inadequacies such as lack of coverage, power and fault tolerance. Failing nodes result in coverage loss and breakage in communication connectivity and hence there is a pressing need for a fault tolerant system to allow replacing of the failed nodes. In this dissertation, a unique hybrid sensor network is demonstrated that includes a host of mobile sensor platforms. It is shown that the coverage area of the static sensor network can be improved by self-organizing the mobile sensor platforms to allow interaction with the static sensor nodes and thereby increase the coverage area. The performance of the hybrid sensor network is analyzed for a set of N mobile sensors to determine and optimize parameters such as the position of the mobile nodes for maximum coverage of the sensing area without loss of signal between the mobile sensors, static nodes and the central control station. A novel approach to tracking dynamic targets is also presented. Unlike other tracking methods that are based on computationally complex methods, the strategy adopted in this work is based on a computationally simple but effective technique of received signal strength indicator measurements. The algorithms developed in this dissertation are based on a number of reasonable assumptions that are easily verified in a densely distributed sensor network and require simple computations that efficiently tracks the target in the sensor field. False alarm rate, probability of detection and latency are computed and compared with other published techniques. The performance analysis of the tracking system is done on an experimental testbed and also through simulation and the improvement in accuracy over other methods is demonstrated.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Modeling and Simulation PhD
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Wang, Chaohui. "Distributed and Higher-Order Graphical Models : towards Segmentation, Tracking, Matching and 3D Model Inference." Phd thesis, Ecole Centrale Paris, 2011. http://tel.archives-ouvertes.fr/tel-00658765.
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This thesis is devoted to the development of graph-based methods that address several of the most fundamental computer vision problems, such as segmentation, tracking, shape matching and 3D model inference. The first contribution of this thesis is a unified, single-shot optimization framework for simultaneous segmentation, depth ordering and multi-object tracking from monocular video sequences using a pairwise Markov Random Field (MRF). This is achieved through a novel 2.5D layered model where object-level and pixel-level representations are seamlessly combined through local constraints. Towards introducing high-level knowledge, such as shape priors, we then studied the problem of non-rigid 3D surface matching. The second contribution of this thesis consists of a higher-order graph matching formulation that encodes various measurements of geometric/appearance similarities and intrinsic deformation errors. As the third contribution of this thesis, higher-order interactions were further considered to build pose-invariant statistical shape priors and were exploited for the development of a novel approach for knowledge-based 3D segmentation in medical imaging which is invariant to the global pose and the initialization of the shape model. The last contribution of this thesis aimed to partially address the influence of camera pose in visual perception. To this end, we introduced a unified paradigm for 3D landmark model inference from monocular 2D images to simultaneously determine both the optimal 3D model and the corresponding 2D projections without explicit estimation of the camera viewpoint, which is also able to deal with misdetections/occlusions
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Sandro, Manservisi. "Optimal Boundary and Distributed Controls for the Velocity Tracking Problem for Navier-Stokes Flows." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30608.
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The velocity tracking problem is motivated by the desire to match a desired target flow with a flow which can be controlled through time dependent distributed forces or time dependent boundary conditions.
The flow model is the Navier-Stokes equations for a viscous incompressible fluid and different kinds of controls are studied. Optimal distributed and boundary controls minimizing a quadratic functional and an optimal bounded distributed control are investigated. The distributed optimal and the bounded control are compared with a linear feedback control.
Here, a unified mathematical formulation, covering several specific classes of meaningful control problems in bounded domains, is presented with a complete and detailed analysis of all these time dependent optimal control velocity tracking problems. We concentrate not only on questions such as existence and necessary first order conditions but also on discretization and computational aspects.
The first order necessary conditions are derived in the continuous, in the semidiscrete time approximation and in the fully finite element discrete case. This derivation is needed to obtain an accurate meaningful numerical algorithm with a satisfactory convergence rate. The gradient algorithm is used and several numerical computations are performed to compare and understand the limits imposed by the theory. Some computational aspects are discussed without which problems of any realistic size would remain intractable.Ph. D.
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Conte, Armond S. II. "Censoring and Fusion in Non-linear Distributed Tracking Systems with Application to 2D Radar." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4068.
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The objective of this research is to study various methods for censoring state estimate updates generated from radar measurements. The generated 2-D radar data are sent to a fusion center using the J-Divergence metric as the means to assess the quality of the data. Three different distributed sensor network architectures are considered which include different levels of feedback. The Extended Kalman Filter (EKF) and the Gaussian Particle Filter (GPF) were used in order to test the censoring methods in scenarios which vary in their degrees of non-linearity. A derivation for the direct calculation of the J-Divergence using a particle filter is provided. Results show that state estimate updates can be censored using the J-Divergence as a metric controlled via feedback, with higher J-Divergence thresholds leading to a larger covariance at the fusion center.
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Munoz-Coreas, Edgard. "Stargrazer One: A New Architecture for Distributed Maximum Power Point Tracking of Solar Photovoltaic Sources." UKnowledge, 2015. http://uknowledge.uky.edu/ece_etds/76.
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The yield from a solar photovoltaic (PV) source is dependent on factors such as light and temperature. A control system called a maximum power point tracker (MPPT) ensures that the yield from a solar PV source is maximized in spite of these factors. This thesis presents a novel implementation of a perturb and observe (PO) MPPT.
The implementation uses a switched capacitor step down converter and a custom digital circuit implementation of the PO algorithm. Working in tandem, the switched capacitor step down converter and the custom digital circuit implementation were able to successfully track the maximum power point of a simulated solar PV source. This implementation is free of the overhead encountered with general purpose processor based MPPT implementations. This makes this MPPT system a valid candidate for applications where general purpose processors are undesirable.
This document will begin by discussing the current state of MPPT research. Afterward, this thesis will present studies done to be able to use the chosen switched capacitor step down converter. Then the digital circuit PO implementation will be discussed in detail. Simulations of the architecture will be presented. Finally, experimental validation using a hardware prototype will be shown.
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Hegazy, Tamir A. "A Distributed Approach to Dynamic Autonomous Agent Placement for Tracking Moving Targets with Application to Monitoring Urban Environments." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4901.
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The problem of dynamic autonomous agent placement for tracking moving targets arises in many real-life applications, such as rescue operations, security, surveillance, and reconnaissance. The objective of this thesis is to develop a distributed hierarchical approach to address this problem. After the approach is developed, it is tested on a number of urban surveillance scenarios. The proposed approach views the placement problem as a multi-tiered architecture entailing modules for low-level sensor data preprocessing and fusion, decentralized decision support, knowledge building, and centralized decision support. This thesis focuses upon the modules of decentralized decision support and knowledge building. The decentralized decision support module requires a great deal of coordination among agents to achieve the mission objectives. The module entails two classes of distributed algorithms: non-model-based algorithms and model-based algorithms. The first class is used as a place holder while a model is built to describe agents knowledge about target behaviors. After the model is built and evaluated, agents switch to the model-based algorithms. To apply the approach to urban environments, urban terrain zones are classified, and the problem is mathematically formulated for two different types of urban terrain, namely low-rise, widely spaced and high-rise, closely spaced zones. An instance of each class of algorithms is developed for each of the two types of urban terrain. The algorithms are designed to run in a distributed fashion to address scalability and fault tolerance issues. The class of model-based algorithms includes a distributed model-based algorithm for dealing with evasive targets. The algorithm is designed to improve its performance over time as it learns from past experience how to deal with evasive targets. Apart from the algorithms, a model estimation module is developed to build motion models online from sensor observations. The approach is evaluated through a set of simulation experiments inspired from real-life scenarios. Experimental results reveal the superiority of the developed algorithms over existing ones and the applicability of the online model-building method. Therefore, it is concluded that the overall distributed approach is capable of handling agent placement or surveillance applications in urban environments among other applications.
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Sodhi, Bir Apaar Singh. "DATA MINING: TRACKING SUSPICIOUS LOGGING ACTIVITY USING HADOOP." CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/271.
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In this modern rather interconnected era, an organization’s top priority is to protect itself from major security breaches occurring frequently within a communicational environment. But, it seems, as if they quite fail in doing so. Every week there are new headlines relating to information being forged, funds being stolen and corrupt usage of credit card and so on. Personal computers are turned into “zombie machines” by hackers to steal confidential and financial information from sources without disclosing hacker’s true identity. These identity thieves rob private data and ruin the very purpose of privacy. The purpose of this project is to identify suspicious user activity by analyzing a log file which then later can help an investigation agency like FBI to track and monitor anonymous user(s) who seek for weaknesses to attack vulnerable parts of a system to have access of it. The project also emphasizes the potential damage that a malicious activity could have on the system. This project uses Hadoop framework to search and store log files for logging activities and then performs a ‘Map Reduce’ programming code to finally compute and analyze the results.
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Wu, Jiande. "Parallel Computing of Particle Filtering Algorithms for Target Tracking Applications." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1953.
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Particle filtering has been a very popular method to solve nonlinear/non-Gaussian state estimation problems for more than twenty years. Particle filters (PFs) have found lots of applications in areas that include nonlinear filtering of noisy signals and data, especially in target tracking. However, implementation of high dimensional PFs in real-time for large-scale problems is a very challenging computational task.
Parallel & distributed (P&D) computing is a promising way to deal with the computational challenges of PF methods. The main goal of this dissertation is to develop, implement and evaluate computationally efficient PF algorithms for target tracking, and thereby bring them closer to practical applications. To reach this goal, a number of parallel PF algorithms is designed and implemented using different parallel hardware architectures such as Computer Cluster, Graphics Processing Unit (GPU), and Field-Programmable Gate Array (FPGA). Proposed is an improved PF implementation for computer cluster - the Particle Transfer Algorithm (PTA), which takes advantage of the cluster architecture and outperforms significantly existing algorithms. Also, a novel GPU PF algorithm implementation is designed which is highly efficient for GPU architectures. The proposed algorithm implementations on different parallel computing environments are applied and tested for target tracking problems, such as space object tracking, ground multitarget tracking using image sensor, UAV-multisensor tracking. Comprehensive performance evaluation and comparison of the algorithms for both tracking and computational capabilities is performed. It is demonstrated by the obtained simulation results that the proposed implementations help greatly overcome the computational issues of particle filtering for realistic practical problems.
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Paruchuri, Sai Tej. "Output Regulation of Systems Governed by Delay Differential Equations: Approximations and Robustness." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98409.
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This thesis considers the problem of robust geometric regulation for tracking and disturbance rejection of systems governed by delay differential equations. It is well known that geometric regulation can be highly sensitive to system parameters and hence such designs are not always robust. In particular, when employing numerical approximations to delay systems, the resulting finite dimensional models inherit natural approximation errors that can impact robustness. This demonstrates this lack of robustness and then addresses robustness by employing versions of robust regulation that have been developed for infinite dimensional systems. Numerical examples are given to illustrate the ideas and to test the robustness of the regulator.M.S.
Recent years have seen a surge in the everyday application of complex mechanical and electrical systems. These systems can perform complex tasks; however, the increased complexity makes it harder to control them. An example of such a system is a semi-autonomous car designed to stay within a designated lane. One of the most commonly used approaches for controlling such systems is called output regulation. In the above example, the output regulator regulates the output of the car (position of the car) to follow the reference output (the road lane). Traditionally, the design of output regulators assumes complete knowledge of the system. However, it is impossible to derive equations that govern complex systems like a car. This thesis analyzes the robustness of output regulators in the presence of errors in the system. In particular, the focus is on analyzing output regulators implemented to delay-differential equations. These are differential equations where the rate of change of states at the current time depends on the states at previous times. Furthermore, this thesis addresses this problem by employing the robust versions of the output regulators.
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Gallagher, Jonathan G. "Likelihood as a Method of Multi Sensor Data Fusion for Target Tracking." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244041862.
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Gonzalez, Ander. "Integration of photovoltaic sources and battery based storage systems – A DC analysis and distributed maximum power point tracking solution." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/282059/4/TOC_vf.pdf.
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In this thesis the integration of photovolatic (PV) generation and energy storage into the electrical grid is discussed. Although the studied system is for grid tied applications, here the integration of the PV generation and the energy storage system (ESS) on the DC-side of the system is addressed. The work contained in this thesis focuses on the integration of the DC-working parts before interfacing them with the grid through the use of an inverter and seeks an increasing in the energy that the system can deliver.First, a study of classical systems that present well-differentiated parts is presented: PV generation, a lithium-ion battery based ESS, the utility grid and a residential electricity consumer. PV installations of 3 and 10kWp are considered together with storage capacities ranging from 1 to 9kWh. This yields interesting insights on how the system works based on the timing of the generation and consumption of energy. The results are used to highlight the weaknesses of the selected converter arrangement for the interfacing of the PV source and the ESS. Results show that the system is rather stiff and lacks from conversion efficiency when it needs to work in a wide range of powers, mainly due to low consumer power demand during battery discharge. In this first part of the thesis, three solutions to workaround the efficiency problem are proposed: reducing the difference between the ESS and the DC-bus voltages, using isolated converters to interface the ESS, or adopting a new arrangement of the parts of the system. One of the first two proposed solutions should be adopted if the same system topology is to be kept. These two solutions address the efficiency problem when the ESS is involved in the energy conversion. The third solution is proposed as alternative to the classical systems that use a DC-bus to exchange power with the different parts of the system. The new proposed arrangement features a distributed maximum power point (DMPPT) type system that includes storage at module level. DMPPT systems are able to track the maximum power point (MPPT) of each panel separately by connecting a small power electronic converter (PEC) to each PV panel. They are specially useful when the PV installation receives uneven irradiance, i.e. shadows are present in some of the panels, increasing the annual yield of PV energy from 7 to 30% as reported in the literature. Unfortunately, this kind of systems cannot always handle high irradiance mismatches, and fail to track the maximum power point (MPP) throughout the whole installation in some cases. Including batteries at module level instead of connecting them to the DC-bus, allows for increasing the MPPT range of the system, virtually to any severity of irradiance mismatch (depending on the state of charge (SoC) of the battery pack), as well as adding storage capability to the system. The novel proposed system is able to workaround the problems of using non-isolated converters, achieving PV energy conversion efficiencies from 86% (for at least 10% of the peak power) to 90% and storage charge/discharge efficiencies ranging from 86% to 95%. Besides, it brings the opportunity to exploit the synergies of having storage at module level in systems that combine renewable energies and storage. Moreover, DMPPT systems achieve superior PV generation under partially shaded conditions when compared to classical PV arrays increasing the PV generation when compared to classical or centralized PV installations up to 45% in power as reported in the literature.In the second part of the thesis, the proposed novel DMPPT topology is presented. The whole system is fully designed from scratch, including PECs, sizing of the different parts of the modules, embedded control loops of the modules and supervisory control of the whole system. Finally, the results obtained from running the proposed system are shown and discussed, and suggestions given on how to operate and protect the system. Experimental results are obtained using a 1.5kWp PV power and 1.5kWh capacity test bench built for that purpose.The proposed system is able to generate PV energy, store the energy coming from PV generation and inject the generated and stored energy into the grid. The proposed system extends the MPPT capability of storage-less series-connected DMPPT systems. This is achieved by using the batteries not only to store energy when required, but also to compensate the power mismatch across DMPPT modules of the same string when the output voltage of the modules becomes a limit. It also presents a modular and upgradable approach to PV systems including storage. This modularity also brings fault tolerance, and an ability to continue working after failure of one or more of the DMPPT modules by partially or completely isolating the faulty module (depending on the nature of the fault). Moreover, the addition of the DC-DC converters allows for the use of different PV panels in the system, i.e. from different manufacturers or technologies.In conclusion, the presented system is very flexible, can be designed for a wide range of power levels and energy storage sizes, and presents improved reliability when compared to other series-connected DMPPT systems.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Jovanoska, Snezhana [Verfasser], Reiner [Akademischer Betreuer] Thomä, Wolfgang [Gutachter] Koch, and Dirk [Gutachter] Heberling. "Localisation and tracking of people using distributed UWB sensors / Snezhana Jovanoska ; Gutachter: Wolfgang Koch, Dirk Heberling ; Betreuer: Reiner Thomä." Ilmenau : TU Ilmenau, 2020. http://d-nb.info/1216038945/34.
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Moraes, Rodrigo Saar de. "A distributed cooperative multi-UAV coordination system for crowd monitoring applications." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180131.
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Ao observar a situação atual, na qual atos de vandalismo e terrorismo tornaram-se frequentes e cada vez mais presentes ao redor do mundo, principalmente em grandes cidades, torna-se clara a necessidade de equipar as forças policiais com tecnologias de observação e monitoramento inteligentes, capazes de identificar e monitorar indivíduos potencialmente perigosos que possam estar infiltrados nas multidões. Ao mesmo tempo, com sua recente popularização, veículos aéreos não tripulados, também chamados VANTs e conhecidos popularmente como "drones", acabaram por tornar-se ferramentas baratas e eficientes para diversas aplicações, incluindo observação, fornecendo a seus utilizadores a capacidade de monitorar alvos, áreas, ou prédios de forma segura e quase imperceptível. Unindo estas duas tendências, este trabalho apresenta o desenvolvimento de um sistema multi-VANT para observção de alvos móveis em multidões, demonstrando a possibilidade de utilização de pequenos VANTs comerciais comuns para o monitoramento de grupos de pedestres. O principal objetivo de tal sistema é monitorar continuamente indivíduos de interesse em um grupo de pessoas, visitando cada um destes indivíduos alternadamente, de forma a manter um registro geral do estado de cada um deles Um sistema deste tipo poderia, por exemplo, ser utilizado por autoridades no controle de manifestações e outras atividades em que grandes grupos de pessoas estejam envolvidos, ajudando a polícia e outros órgãos a identificar indivíduos com comportamento suspeito ou agressivo mais rapidamente, evitando ou minimizando os efeitos de atitudes de vandalismo e de ataques terroristas. Com o intuíto de abordar tal problema da forma mais completa e adequada possível, esta tese apresenta a concepção e o desenvolvimento de um sistema híbrido composto de três diferentes algoritmos: um algoritmo de distribuição de alvos; um de roteamento; e um de repasse de alvos. Primeiramente, neste sistema, um algoritmo de distribuição de alvos baseado em um paradigma de mercado que simula um leilão distribui os alvos entre os VANTs da melhor forma possível. Os VANTs, por sua vez, utilizam um algoritmo genético de roteamento para resolver uma instância do Problema do Caixeiro Viajante e decidir a melhor rota para visitar cada alvo sob sua responsabilidade. Ao mesmo tempo, o sistema analisa a necessidade de redistribuição dos alvos, ativando um algoritmo capaz de realizar esta ação ao perceber sua necessidade quando na iminência de perder algum alvo de vista. Ao fim de seu desenvolvimento, o sistema proposto foi testado em uma série de experimentos especialmente desenvolvidos para avaliar seu desempenho em situações controladas e comprovar sua eficiência para realizar a missão pretendida.Observing the current scenario, where terrorism and vandalism acts have become commonplace, particularly in big cities, it becomes clear the need to equip law enforcement forces with an efficient observation method, capable of identifying and observing potentially threatening individuals on crowds, to avoid or minimize damage in case of attacks. Moreover, with the popularization of small lightweight Unmanned Aerial Vehicles (UAVs), these have become an affordable and efficient tool, which can be used to track and follow targets or survey areas or buildings quietly, safely and almost undetectably. This work presents the development of a multi-UAV based crowd monitoring system, demonstrating a system that uses small Commercial Of The Shelf (COTS) UAVs to periodically monitor a group of moving walking individuals. The goal of this work is to develop a coordination system for a swarm of UAVS capable of continuously monitoring a large group of individuals (targets) in a crowd, alternately observing each of them at a time while trying to not lose sight of any of these targets. A system equipped with a group of UAVs running this proposal can be used for law-enforcement applications, assisting authorities to monitor crowds in order to identify and to follow suspicious individuals that can have attitudes that could be classified as vandalism or linked to terrorist attack attempts To address this problem a system composed of three parts is proposed and was developed in this thesis. First, an auction algorithm was put in place to distribute interest targets among the multiple UAVs. The UAVs, in turn, make use of a genetic algorithm to calculate the order in which they would visit each of the targets on their observation queue. Moreover, a target handover algorithm was also implemented to redistribute targets among the UAVs in case the system judged that a target was about to be lost by its current observer UAV. The proposed system was evaluated through a set of experiments set-up to verify and to demonstrate the system capabilities to perform such monitoring task, proving its efficiency. During these experiments, it is made clear that the system as a whole has a great potential to solve this kind of moving target monitoring problem that can be mapped to a Time Dependent Travel Salesman Problem (TDTSP), observing targets, and redistributing them among UAVs as necessary during the mission.
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Sitanayah, Lanny. "Finding boundary cycles in location-free low density wireless sensor networks for mobile target tracking." University of Western Australia. School of Computer Science and Software Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0158.
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Wireless Sensor Networks (WSNs) comprise a large number of sensor nodes, which are spread out within a region and communicate using wireless links. In some WSN applications, recognizing boundary nodes is important for topology discovery, geographic routing and tracking. In this thesis, we study the problem of identifying the boundary nodes of a WSN. In a WSN, close-by nodes can communicate with their neighbors and have the ability to estimate distances to nearby nodes, but not necessarily the true distances. Our objective is to find the boundary nodes by using the connectivity relation and neighbor distance information without any knowledge of node locations. Moreover, our main aim is to design a distributed algorithm that works even when the average degree is low. We propose a heuristic algorithm to find the boundary nodes which are connected in a boundary cycle of a location-free, low density, randomly deployed WSN. We develop the key ideas of our boundary detection algorithm in the centralized scenario and extend these ideas to the distributed scenario. Then, we show by simulation experiments that the distributed implementation outperforms the centralized one. The centralized implementation relies on the connectivity of the network to the base station. Therefore, for low density disconnected networks, the algorithm cannot find boundaries in partitions of the network that cannot establish connection to the base station. This condition leads to a low quality of boundary discovery. In contrast, the distributed implementation is more realistic for real WSNs, especially for relatively sparse networks when all local information cannot be collected very well due to sparse connectivity. In low-degree disconnected networks, the simulation results show that the distributed implementation has a higher quality of boundaries compared to the centralized implementation.
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Khalili, Mohsen. "Distributed Adaptive Fault-Tolerant Control of Nonlinear Uncertain Multi-Agent Systems." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1503622016617833.
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Casbeer, David W. "Decentralized Estimation Using Information Consensus Filters with a Multi-static UAV Radar Tracking System." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2779.pdf.
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Eggers, Martin Hermann Albert [Verfasser], Bernd [Akademischer Betreuer] Radig, and Alois [Akademischer Betreuer] Knoll. "Perspective-Adjusting Appearance Model for Distributed Multi-View Person Tracking / Martin Hermann Albert Eggers. Gutachter: Alois Knoll ; Bernd Radig. Betreuer: Bernd Radig." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1061126080/34.
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Liu, Junbin. "Distributed low-power image processing in wireless sensor networks for intelligent video surveillance applications." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/63311/1/Junbin_Liu_Thesis.pdf.
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Distributed Wireless Smart Camera (DWSC) network is a special type of Wireless Sensor Network (WSN) that processes captured images in a distributed manner. While image processing on DWSCs sees a great potential for growth, with its applications possessing a vast practical application domain such as security surveillance and health care, it suffers from tremendous constraints. In addition to the limitations of conventional WSNs, image processing on DWSCs requires more computational power, bandwidth and energy that presents significant challenges for large scale deployments. This dissertation has developed a number of algorithms that are highly scalable, portable, energy efficient and performance efficient, with considerations of practical constraints imposed by the hardware and the nature of WSN. More specifically, these algorithms tackle the problems of multi-object tracking and localisation in distributed wireless smart camera net- works and optimal camera configuration determination.
Addressing the first problem of multi-object tracking and localisation requires solving a large array of sub-problems. The sub-problems that are discussed in this dissertation are calibration of internal parameters, multi-camera calibration for localisation and object handover for tracking. These topics have been covered extensively in computer vision literatures, however new algorithms must be invented to accommodate the various constraints introduced and required by the DWSC platform.
A technique has been developed for the automatic calibration of low-cost cameras which are assumed to be restricted in their freedom of movement to either pan or tilt movements. Camera internal parameters, including focal length, principal point, lens distortion parameter and the angle and axis of rotation, can be recovered from a minimum set of two images of the camera, provided that the axis of rotation between the two images goes through the camera's optical centre and is parallel to either the vertical (panning) or horizontal (tilting) axis of the image.
For object localisation, a novel approach has been developed for the calibration of a network of non-overlapping DWSCs in terms of their ground plane homographies, which can then be used for localising objects. In the proposed approach, a robot travels through the camera network while updating its position in a global coordinate frame, which it broadcasts to the cameras. The cameras use this, along with the image plane location of the robot, to compute a mapping from their image planes to the global coordinate frame. This is combined with an occupancy map generated by the robot during the mapping process to localised objects moving within the network.
In addition, to deal with the problem of object handover between DWSCs of non-overlapping fields of view, a highly-scalable, distributed protocol has been designed. Cameras that follow the proposed protocol transmit object descriptions to a selected set of neighbours that are determined using a predictive forwarding strategy. The received descriptions are then matched at the subsequent camera on the object's path using a probability maximisation process with locally generated descriptions.
The second problem of camera placement emerges naturally when these pervasive devices are put into real use. The locations, orientations, lens types etc. of the cameras must be chosen in a way that the utility of the network is maximised (e.g. maximum coverage) while user requirements are met. To deal with this, a statistical formulation of the problem of determining optimal camera configurations has been introduced and a Trans-Dimensional Simulated Annealing (TDSA) algorithm has been proposed to effectively solve the problem.
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Kangude, Shantanu. "CSMA with Implicit Scheduling through State-keeping: A Distributed MAC Framework for QoS in Broadcast LANs." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05132004-132109/unrestricted/kangude%5Fshantanu%5F200407%5Fphd.pdf.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005. Directed by John Copeland.Copeland, John, Committee Chair ; Owen, Henry, Committee Member ; Sivakumar, Raghupathy, Committee Member ; Lanterman, Aaron, Committee Member ; Dos Santos, Andre, Committee Member. Includes bibliographical references.
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Kulathumani, Vinodkrishnan. "Network Abstractions for Designing Reliable Applications Using Wireless Sensor Networks." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211560039.
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Kern, Richard Michael [Verfasser], Boris [Akademischer Betreuer] Lohmann, Oliver [Gutachter] Sawodny, and Boris [Gutachter] Lohmann. "Design and Experimental Validation of Output Feedback Tracking Controllers for a Pneumatic System with Distributed Parameters / Richard Michael Kern ; Gutachter: Oliver Sawodny, Boris Lohmann ; Betreuer: Boris Lohmann." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1201086310/34.
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Ajwad, Syed Ali. "Distributed control of multi-agent systems under communication constraints : application to robotics." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2264.
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Les Systèmes Multi-Agents (SMA) ont gagné en popularité en raison de leur vaste gamme d'applications. Les SMA sont utilisés pour atteindre des objectifs complexes qui ne pourraient être atteints par un seul agent. La communication et l'échange d'informations entre les agents d'un SMA sont essentiels pour contrôler son comportement coopératif. Les agents partagent leurs informations avec leurs voisins pour atteindre un objectif commun, ils n'ont donc pas besoin d'unité centrale de surveillance. Cependant, la communication entre les agents est soumise à diverses contraintes pratiques. Ces contraintes incluent des périodes d'échantillonnage irrégulières et asynchrones et la disponibilité d'états partiels uniquement. Ces contraintes posent des défis théoriques et pratiques importants. Dans cette thèse, nous étudions deux problèmes fondamentaux liés au contrôle coopératif distribué, à savoir le consensus et le contrôle de formation pour un SMA à double intégrateur sous ces contraintes. On considère que chaque agent du réseau ne peut mesurer et transmettre son état de position qu'à des instants d'échantillonnage non uniformes et asynchrones. De plus, la vitesse et l'accélération ne sont pas disponibles. Dans un premier temps, nous étudions le problème du contrôle distribué du suivi de consensus. Un algorithme de suivi de leader basé sur l'observateur à temps discret continu est proposé. L'observateur estime la position et la vitesse de l'agent et de son voisin en temps continu à partir des données de position échantillonnées disponibles. Ces états estimés sont ensuite utilisés pour le calcul de l'entrée de commande. Les scénarios de topologie fixe et de topologie commutée sont discutés. Deuxièmement, un protocole de suivi de formation distribué basé sur le consensus est conçu pour réaliser des modèles de formation fixes et variant dans le temps. Le problème d'évitement de collision est également étudié dans cette thèse. Un mécanisme d'évitement de collision basé sur la fonction de potentiel artificiel (APF) est incorporé à l'algorithme de suivi de formation pour empêcher les collisions entre les agents tout en convergeant vers la position souhaitée. Enfin, les algorithmes proposés sont appliqués sur un réseau multi-robots, composé de robots à entraînement différentiel utilisant Robot Operating System (ROS). Un nouveau schéma est proposé pour faire face aux contraintes non holonomiques du robot. L'efficacité des algorithmes sont démontrées à la fois par des résultats de simulation et des expérimentationsMulti-agent systems (MAS) have gained much popularity due to their vast range of applications. MAS is deployed to achieve more complex goals which could not be realized by a single agent alone. Communication and information exchange among the agents in a MAS is crucial to control its cooperative behavior. Agents share their information with their neighbors to reach a common objective, thus do not require any central monitoring unit. However, the communication among the agents is subject to various practical constraints. These constraints include irregular and asynchronous sampling periods and the availability of partial states only. Such constraints pose significant theoretical and practical challenges. In this thesis, we investigate two fundamental problems related to distributed cooperative control, namely consensus and formation control, of double-integrator MAS under these constraints. It is considered that each agent in the network can measure and transmit its position state only at nonuniform and asynchronous sampling instants. Moreover, the velocity and acceleration are not available. First, we study the problem of distributed control of leader-following consensus. A continuous-discrete time observer based leader-following algorithm is proposed. The observer estimates the position and velocity of the agent and its neighbor in continuous time from the available sampled position data. Then these estimated states are used for the computation of the control input. Both fixed and switching topology scenarios are discussed. Secondly, a consensus based distributed formation tracking protocol is designed to achieve both fixed and time-varying formation patterns. Collision avoidance problem is also studied in this thesis. An Artificial Potential Function (APF) based collision avoidance mechanism is incorporated with the formation tracking algorithm to prevent collisions between the agents while converging to a desired position. Finally, the proposed algorithms are applied on a multi-robot network, consisting of differential drive robots using Robot Operating System (ROS). A new scheme is proposed to deal with nonholonomic constraints of the robot. Efficiency of the designed algorithms and their effectiveness in real world applications are shown through both simulation and hardware results
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McClure, Morgan Taylor. "A Modular Architecture for DC-AC Conversion." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1340812711.
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Hamilton, Benjamin Russell. "Applications of bayesian filtering in wireless networks: clock synchronization, localization, and rf tomography." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44707.
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In this work, we investigate the application of Bayesian filtering techniques such as Kalman Filtering and Particle filtering to the problems of network time synchronization, self-localization and radio-frequency (RF) tomography in wireless networks. Networks of large numbers of small, cheap, mobile wireless devices have shown enormous potential in applications ranging from intrusion detection to environmental monitoring. These applications require the devices to have accurate time and position estimates, however traditional techniques may not be available. Additionally RF tomography offers a new paradigm to sense the network environment and could greatly enhance existing network capabilities.
While there are some existing works addressing these problems, they all suffer from limitations. Current time synchronization methods are not energy efficient on small wireless devices with low quality oscillators. Existing localization methods do not consider additional sources of information available to nodes in the network such as measurements from accelerometers or models of the shadowing environment in the network. RF tomography has only been examined briefly in such networks, and current algorithms can not handle node mobility and rely on shadowing models that have not been experimentally verified.
We address the time synchronization problem by analyzing the characteristics of the clocks in small wireless devices, developing a model for it, and then applying a Kalman filter to track both clock offset and skew. In our investigation into RF tomography, we present a method using a Kalman filter which jointly estimates and tracks static and dynamic objects in the environment. We also use channel measurements collected from a field test of our RF tomography testbed to compare RF shadowing models. For the localization problem, we present two algorithms incorporating additional information for improved localization: one based on a distributed extended Kalman filter that combines local acceleration measurements with signal strength measurements for improved localization, and another that uses a distributed particle filter to incorporate a model of the channel environment.
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Tuffery, Adrien. "Conception d’amplificateurs de puissance reconfigurables en technologie CMOS avancée pour une application 4G LTE." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14682/document.
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Cette thèse porte sur la conception d’amplificateurs de puissance reconfigurables en technologie CMOS avancée pour une application cellulaire de 4ème génération. Dans les systèmes de communication sans fil, le rendement énergétique est un critère primordial qui impacte la durée d’utilisation de la batterie. Principalement déterminé par la consommation d’énergie du transmetteur, il est plus particulièrement lié à celle de l’amplificateur de puissance (PA). Pour les terminaux mobiles de 4ème génération (4G), les techniques de transmission et les modulations utilisées pour atteindre les débits de données visés induisant une dynamique importante du signal à transmettre, l’implémentation de techniques d’amélioration du rendement autour du PA devient indispensable, afin de le reconfigurer en puissance.Nous avons mis au point dans ce travail de recherche des architectures innovantes utilisant les techniques d’amélioration du Power Cell Switching (PCS) et de l’Envelope Tracking (ET). Le double objectif visé étant d’améliorer significativement le rendement pour les faibles niveaux de puissance et d’apporter de la flexibilité par rapport à un PA utilisé seul. Une première architecture utilisant la technique du PCS totalement intégré en technologie CMOS 65nm de STMicroelectronics, mettant en œuvre des transformateurs comme combineurs de puissance, a été réalisée pour valider la fonctionnalité du concept proposé. Puis une deuxième architecture combinant les techniques du PCS et de l’ET a été conçue, afin d’évaluer les avantages qu’apporte la combinaison de ces deux techniques par rapport à un PA fonctionnant seul et à un PA développé utilisant la technique du PCSThis thesis deals with the design of reconfigurable power amplifiers implemented in CMOS technology for 4G LTE application. For the next generation communication systems such as 4G LTE, orthogonal frequency division multiplexing (OFDM) is employed for a wideband communication. Indeed, signal information is encoded both in amplitude and phase domains, which results in a higher peak to average power ratio than for 2G and 3G systems. Consequently, the overall power amplifier (PA) efficiency does not only depend on efficiency at maximum power, but also and mainly on efficiency at back-off level where the PA operates most of the time. Obviously, classical PA architectures do not address this problem, because it can only achieve maximum efficiency at a single power level, usually around the peak output power. Therefore, the overall efficiency of the PA is considerably low and efficiency improvement techniques are required to increase the battery life-time. This thesis exposes innovative architectures using Power Cell Switching (PCS) and Envelope Tracking (ET) techniques. The main objective of the proposed architectures is to significantly improve the average efficiency in comparison with a stand-alone power amplifier at power back-off. Consequently, a reconfigurable PA architecture using a 4-step PCS technique has been implemented in CMOS 65nm technology. A second architecture was designed to evaluate the improvement obtained with the combination of these two techniques
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Cui, Beibei. "Image processing applications in object detection and graph matching : from Matlab development to GPU framework." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCA002.
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Déterminer des mises en correspondance d’objet, ou de caractéristiques d’objet, dans des images présente un grand intérêt pour beaucoup d’applications telles que la détection et le suivi de cible, l’estimation du flot optique, l’identification, et d’autres tâches dérivées. Dans cette thèse, nous abordons le problème de mise en correspondance dans le cadre général de l’optimisation de l’appariement de graphe, dans le but de contribuer, comme résultat final, au développement de nouveaux algorithmes parallèles implémentés sur plateforme GPU (Graphics Processing Unit). Le problème d’appariement de graphe peut être décliné de diverses manières suivant l’application considérée. Nous observons un fossé entre les applications basées sur des fonctions de coût locales et les applications avec des fonctions de coût d’ordre supérieur, évaluant la similarité entre les arêtes du graphe, ou les hyperliens lorsqu’il s’agit d’un hypergraphe. La première classe d’applications comporte des algorithmes de résolution basés sur des calculs de convolution et possède déjà des implémentations parallèles sur GPU. La deuxième classe d’applications met l’accent sur les relations géométriques entre caractéristiques extraites de l’image, transformant le problème de mise en correspondance en un programme quadratique en nombre entiers avec contraintes, pour lequel nous n’avons pas trouvé de solution GPU accessible actuellement.Deux types d’approche ont été adoptées pour contribuer à la problématique d’appariement de graphe sur GPU. Premièrement, nous étudions différentes déclinaisons de cette problématique via l’utilisation de la plateforme Matlab afin de pouvoir réutiliser et fournir des solutions représentatives de l’état de l’art, ainsi que des protocoles d’expérimentation et des données d’entrée nécessaires pour une plateforme GPU dédiée à l’évaluation et la comparaison avec les algorithmes séquentiels sur Matlab. Ainsi, une première partie du travail concerne trois contributions respectivement, aux techniques de soustraction d’arrière-plan et de différence d’image pour la détection, au problème d’extraction de caractéristiques pour la mise en correspondance, et au problème général d’appariement de graphe, toutes basées sur la combinaison de méthodes issues de l’environnement Matlab. Deuxièmement, nous proposons une infrastructure logicielle GPU nouvelle, écrite en CUDA C++, spécifiquement adaptée au problème d’appariement de graphe géométrique, proposant de nouveaux algorithmes parallèles de complexité calculatoire plus réduite, tels que les cartes auto-organisatrices dans le plan, des algorithmes de cluster qui en sont dérivés, et des recherches locales distribuées. Ces algorithmes parallèles sont évalués et comparés aux approches de l’état de l’art pour le problème d’appariement de graphe, en suivant un protocole d’expérimentation identique. Cette plateforme GPU constitue notre principale proposition pour contribuer à combler le fossé entre développement GPU et son application au problème général d’appariement de grapheAutomatically finding correspondences between object features in images is of main interest for several applications, as object detection and tracking, flow velocity estimation, identification, registration, and many derived tasks. In this thesis, we address feature correspondence within the general framework of graph matching optimization and with the principal aim to contribute, at a final step, to the design of new and parallel algorithms and their implementation on GPU (Graphics Processing Unit) systems. Graph matching problems can have many declinations, depending on the assumptions of the application at hand. We observed a gap between applications based on local cost objective functions, and those applications with higher-order cost functions, that evaluate similarity between edges of the graphs, or hyperedges when considering hypergraphs. The former class provides convolution-based algorithms already having parallel GPU implementations. Whereas, the latter class puts the emphasis on geometric inter-feature relationships, transforming the correspondence problem to a purely geometric problem stated in a high dimensional space, generally modeled as an integer quadratic programming, for which we did not find GPU implementations available yet.Two complementary approaches were adopted in order to contribute to addressing higher-order geometric graph matching on GPU. Firstly, we study different declinations of feature correspondence problems by the use of the Matlab platform, in order to reuse and provide state-of-the-art solution methods, as well as experimental protocols and input data necessary for a GPU platform with evaluation and comparison tools against existing sequential algorithms, most of the time developed in Matlab framework. Then, the first part of this work concerns three contributions, respectively, to background and frame difference application, to feature extraction problem from images for local correspondences, and to the general graph matching problem, all based on the combination of methods derived from Matlab environment. Secondly, and based on the results of Matlab developments, we propose a new GPU framework written in CUDA C++ specifically dedicated to geometric graph matching but providing new parallel algorithms, with lower computational complexity, as the self-organizing map in the plane, derived parallel clustering algorithms, and distributed local search method. These parallel algorithms are then evaluated and compared to the state-of-the-art methods available for graph matching and following the same experimental protocol. This GPU platform constitutes our final and main proposal to contribute to bridging the gap between GPU development and higher-order graph matching
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Souza, Éfren Lopes de. "Algoritmos para rastreamento de alvos em áreas quantizadas com redes de sensores sem fio." Universidade Federal do Amazonas, 2014. http://tede.ufam.edu.br/handle/tede/4154.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Target tracking in Wireless Sensor Networks (WSNs) is an application in which the nodes cooperate to estimate the position of one or more objects of interest. In this context, the contributions of this work are fourfold. First, a survey the state-of-the-art about target tracking algorithms, in which we identified three formulations of tracking problem, and we classified them according to their characteristics. Furthermore, we divided the target tracking process in components to make the general understanding easier. Second, we propose and evaluate the PRATIQUE algorithm for tracking animals in forests. In this case, the nodes are organized into a grid to make feasible the use of sensor nodes in this kind of area in such a way that each cell of the grid is a region that can be occupied by the target. The algorithm estimates the cell where the target is, and uses predictions and hybrid clustering to reduce the communication cost and ensure the tracking accuracy. The results of the simulations show that prediction errors are approximately one cell. The third contribution is the TATI algorithm, this algorithm guides a tracker to approach the target. The sensor network is organized into faces to make the cooperation among the nodes easier, and reduce the path between the tracker and the target. The results show that energy consumption is reduced by 15%, and the tracker stays about 10m closer to the target, compared to the baseline. The fourth contribution is a scheme for performing localization and tracking tasks simultaneously in such a way that errors of range-based localization algorithms are reduced. This algorithm takes advantage of the messages sent to track the target to filter the noise in the distance estimation, reducing localization errors while tracking. The results show that the localization errors can be reduced by up to 70%.
Rastreamento de alvos em Redes de Sensores Sem Fio (RSSFs) é um tipo de aplicação em que os nós cooperam para estimar a posição de um ou mais objetos de interesse. Nesse contexto, este trabalho possui quatro contribuições. A primeira contribuição é um levantamento bibliográfico do estado-da-arte, em que identificamos três diferentes formulações de rastreamento e as classificamos de acordo com suas características. Além disso, dividimos o processo de rastreamento em componentes para facilitar o entendimento geral. A segunda contribuição é a elaboração e avaliação do algoritmo PRATIQUE para rastrear animais em florestas. Nesse caso, os nós são organizados em grade para viabilizar a utilização dos nós sensores nesse tipo de área, de forma que cada célula da grade é uma região que pode ser ocupada pelo alvo. O algoritmo estima a célula em que o alvo está, e usa previsão e um esquema híbrido de agrupamento para reduzir o custo de comunicação e garantir a precisão do rastreamento. Os resultados das simulações mostram que os erros de previsão são de aproximadamente uma célula. A terceira contribuição é o algoritmo TATI, esse algoritmo guia um objeto que visa alcançar o alvo. A rede é estruturada em faces para facilitar a cooperação entre os nós e reduzir o caminho entre o objeto guiado e o alvo. Os resultados mostram que o consumo de energia é reduzido em 15% e o objeto guiado fica cerca de 10m mais próximo do alvo, se comparado com a abordagem relacionada. A quarta contribuição é um esquema para executar as tarefas de localização e rastreamento simultaneamente para reduzir os erros dos algoritmos de localização baseados em alcance. As mensagens enviadas para rastrear o alvo são aproveitadas para filtrar os ruídos presentes nas estimativas de distância, reduzindo o erro de localização enquanto o rastreamento ocorre. Os resultados mostram que os erros de localização podem ser reduzidos em até 70%.
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Klimeš, Ondřej. "Komprimované vzorkování pro efektivní sledování objektu senzorovou sítí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400432.
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The master's thesis deals with target tracking. For this a decentralized sensor network using distributed particle filter with likelihood consensus is used. This consensus is based on a sparse representation of local likelihood function in a suitable chosen dictionary. In this thesis two dictionaries are compared: the widely used Fourier dictionary and our proposed B-splines. At the same time, thanks to the sparsity of distributed data, it is possible to implement compressed sensing method. The results are compared in terms of tracking error and communication costs. The thesis also contains scripts and functions in MATLAB.
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Andries, Mihai. "Localisation et suivi d'humains et d'objets, et contrôle de robots au travers d'un sol sensible." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0293.
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Cette thèse explore les capacités d’une intelligence ambiante équipée d’un réseau de capteurs de pression au sol. Elle traite le problème de la perception d’un environnement au travers un réseau de capteurs de basse résolution. Les difficultés incluent l’interpretation des poids dispersés pour des objets avec multiples supports, l’ambiguïté de poids entre des objets, la variation du poids des personnes pendant les activités dynamiques, etc. Nous introduisons des nouvelles techniques, partiellement inspirées du domaine de la vision par l’ordinateur, pour la détection, le suivi et la reconnaissance des entités qui se trouvent sur le sol. Nous introduisons également des nouveaux modes d’interaction entre les environnements équipés de tels capteurs aux sols, et les robots qui évoluent dans ces environnements. Ceci permet l’interprétation non-intrusive des événements qui ont lieu dans des environnements dotés d’une intelligence ambiante, avec des applications dans l’assistance automatisée à domicile, l’aide aux personnes âgées, le diagnostic continu de la santé, la sécurité, et la navigation robotiqueThis thesis explores the capabilities of an ambient intelligence equipped with a load-sensing floor. It deals with the problem of perceiving the environment through a network of low-resolution sensors. Challenges include the interpretation of spread loads for objects with multiple points of support, weight ambiguities between objects, variation of persons’ weight during dynamic activities, etc. We introduce new techniques, partly inspired from the field of computer vision, for detecting, tracking and recognizing the entities located on the floor. We also introduce new modes of interaction between environments equipped with such floor sensors and robots evolving inside them. This enables non-intrusive interpretation of events happening inside environments with embedded ambient intelligence, with applications in assisted living, senile care, continuous health diagnosis, home security, and robotic navigation
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Hu, Wei. "Identification de paramètre basée sur l'optimisation de l'intelligence artificielle et le contrôle de suivi distribué des systèmes multi-agents d'ordre fractionnaire." Thesis, Ecole centrale de Lille, 2019. http://www.theses.fr/2019ECLI0008/document.
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Cette thèse traite de l'identification des paramètres du point de vue de l'optimisation et du contrôle de suivi distribué des systèmes multi-agents d'ordre fractionnaire (FOMASs) en tenant compte des retards, des perturbations externes, de la non-linéarité inhérente, des incertitudes des paramètres et de l'hétérogénéité dans le cadre d'une topologie de communication fixe non dirigée / dirigée. Plusieurs contrôleurs efficaces sont conçus pour réaliser avec succès le contrôle de suivi distribué des FOMASs dans différentes conditions. Plusieurs types d'algorithmes d'optimisation de l'intelligence artificielle et leurs versions modifiées sont appliquées pour identifier les paramètres inconnus des FOMASs avec une grande précision, une convergence rapide et une grande robustesse. Il est à noter que cette thèse fournit un lien prometteur entre la technique d'intelligence artificielle et le contrôle distribuéThis thesis deals with the parameter identification from the viewpoint of optimization and distributed tracking control of fractional-order multi-agent systems (FOMASs) considering time delays, external disturbances, inherent nonlinearity, parameters uncertainties, and heterogeneity under fixed undirected/directed communication topology. Several efficient controllers are designed to achieve the distributed tracking control of FOMASs successfully under different conditions. Several kinds of artificial intelligence optimization algorithms andtheir modified versions are applied to identify the unknown parameters of the FOMASs with high accuracy, fast convergence and strong robustness. It should be noted that this thesis provides a promising link between the artificial intelligence technique and distributed control
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Bai, Jing. "Commande des Systèmes Multi-agent d'Ordre Fractionnaire." Thesis, Ecole centrale de Lille, 2015. http://www.theses.fr/2015ECLI0019/document.
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Ce travail concerne la commande des systèmes multi-agent d’ordre fractionnaire utilisant une topologie de communication fixe. Premièrement, la production en formation avec atténuation absolue et retard de communication est étudiée. Pour cela, une loi de commande et des conditions suffisantes sont proposées. Toutefois, dans certains scénarios, il est souhaitable que tous les agents atteignent la formation souhaitée tout en se déplacent en groupe, au lieu d’un rendez-vous à un point fixe. Ce cas sera traité en étudiant la production en formation avec atténuation relative et retard de communication. Troisièmement, la poursuite par consensus des systèmes avec un état de référence variable dans le temps est étudiée. Une loi de commande commune et une seconde basée sur la prédiction d’erreur sont proposées, et le problème du consensus est résolu quand le graphe de communication contient un arbre dirigé. Il a été prouvé que la convergence du système est plus rapide en utilisant la loi basée sur la prédiction d’erreur plutôt que celle de commande commune. Enfin, les lois de commande ci-dessus sont étendues au cas de la poursuite en formation. En effet, dans de nombreux cas, l'information peut être envoyée à partir d'un état de référence vers les agents voisins uniquement et non pas à l’ensemble des agents. Afin de résoudre ce problème, une loi de commande est proposée afin de résoudre le problème du consensus avec un état de référence constant. Puis, deux lois de commande sont proposées afin de résoudre le problème du consensus avec un état de référence variant dans le temps. Ces lois sont étendues pour résoudre le problème de la poursuite en formationThis thesis focuses on the distributed coordination of fractional-order multi-agent systems under fixed directed communication graph. Firstly, formation producing with absolute damping and communication delay of fractional-order multi-agent systems is studied. A control law is proposed and some sufficient conditions are derived for achieving formation producing. However, in some scenarios, it might be desirable that all agents achieve formation and move as a group, instead of rendezvous at a stationary point. Therefore, secondly, formation producing with relative damping and communication delay is considered. Thirdly, consensus tracking of fractional-order multi-agent systems with a time-varying reference state is studied. A common control law and a control law based on error predictor are proposed, and it is shown that the control laws are effective when a communication graph has directed spanning trees. Meanwhile, it is proved that the convergence of systems is faster using the control law based on error predictor than by the common one. Finally, the above control laws are extended to achieve formation-tracking problems. In fact, in many cases information can be sent from a reference state to only its neighbor agents not to all the agents. In order to solve the above problem, an effective control law is given to achieve consensus with a constant reference state. Then, an effective general control law and an effective particular one are proposed to achieve consensus with a time-varying reference state. Furthermore, the above control laws are extended to achieve the formation tracking problems
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Holt, Ryan S. "Three Enabling Technologies for Vision-Based, Forest-Fire Perimeter Surveillance Using Multiple Unmanned Aerial Systems." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/931.
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The ability to gather and process information regarding the condition of forest fires is essential to cost-effective, safe, and efficient fire fighting. Advances in sensory and autopilot technology have made miniature unmanned aerial systems (UASs) an important tool in the acquisition of information. This thesis addresses some of the challenges faced when employing UASs for forest-fire perimeter surveillance; namely, perimeter tracking, cooperative perimeter surveillance, and path planning. Solutions to the first two issues are presented and a method for understanding path planning within the context of a forest-fire environment is demonstrated. Both simulation and hardware results are provided for each solution.
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Reinecke, Sebastian Felix. "Instrumentierte Strömungsfolger zur Prozessdiagnose in gerührten Fermentern." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-137598.
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Advanced monitoring of the spatio-temporal distribution of process parameters in large-scale vessels and containers such as stirred chemical or bioreactors offers a high potential for the investigation and further optimization of plants and embedded processes. This applies especially to large-scale fermentation biogas reactors where the process performance including the biological processes highly depend on mixing parameters of the complex bio-substrates. Sufficient mixing is a basic requirement for a stable operation of the process and adequate process performance. However, this condition is rarely met in agricultural biogas plants and the process efficiency is often reduced dramatically by inhomogeneities in the agitated vessels. Without a doupt, investigation and monitoring of biochemical parameters, such as the fermentation rate, pH distribution as well as O2 and CO2 concentration is of great importance. Nevertheless, also understanding of non-biological parameters, such as fluid dynamics (flow velocity profiles, circulation times), suspension mixing (homogeneity, location of dead zones and short-circuits) and heat transfer (temperature profiles), is necessary to analyze the impact of mixing on the biological system and also to improve the process efficiency.
However, in most industrial scale applications the acquisition of these parameters and their spatial distributions in the large-scale vessels is hampered by the limited access to the process itself, because sensor mounting or cable connections are not feasible or desired. Therefore, state of the art instrumentation of such reactors is commonly limited to few spatial positions where it is doubtfully assumed that the measured parameters are representative for the whole reaction mixture.
In this work, a concept of flow following sensor particles was developed. The sensor particles allow long-term measurement of spatially distributed process parameters in the chemically and mechanically harsh environments of agitated industrial vessels. Each sensor particle comprises of an onboard measurement electronics that logs the signals of measurement devices, namely temperature, absolute pressure (immersion depth, axial position) and 3D acceleration. The whole electronics is enclosed in a robust neutrally buoyant capsule (equivalent diameter 58.2 mm; sphericity 0.91), to allow free movement with the flow.
The sensor particles were tested in pilot fermenters under comparable flow conditions of biogas fermenters. The experiments proved the applicability of the sensor particles and the robustness to resist the harsh environments of mixing processes. Moreover, the results show the capabilities of the sensor particles to monitor the internal conditions of the vessel correctly and thus deliver significant information about the flow regime. Therefore effects of liquid rheology, vessel geometry, impeller speed and axial impeller position on the macro-mixing process were properly detected. Evaluation of the impeller efficiency and the mixing processes was done based on mixing homogeneity, location of dead zones, axial velocity profiles, circulation time distributions as well as average circulation times, acceleration spectra and temperature profiles that were extracted from the measured data. Furthermore, it is shown, that parameters of mixing models such as circulation number, impeller head, PECLÉT-number and variance of suspended solid particles can be estimated from the measured data.
The main achievement of this work is therefore the development and validation of instrumented flow followers for the investigation of macro-mixing effects in agitated vessels. The sensor particles show potential for employment to real applications such as biogas fermenters or large bioreactors and to monitor and improve the mixing and heating regimes.
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Fortin, Benoît. "Méthodes conjointes de détection et suivi basé-modèle de cibles distribuées par filtrage non-linéaire dans les données lidar à balayage." Phd thesis, Université du Littoral Côte d'Opale, 2013. http://tel.archives-ouvertes.fr/tel-01021085.
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Dans les systèmes de perception multicapteurs, un point central concerne le suivi d'objets multiples. Dans mes travaux de thèse, le capteur principal est un télémètre laser à balayage qui perçoit des cibles étendues. Le problème desuivi multi-objets se décompose généralement en plusieurs étapes (détection, association et suivi) réalisées de manière séquentielle ou conjointe. Mes travaux ont permis de proposer des alternatives à ces méthodes en adoptant une approche "track-before-detect" sur cibles distribuées qui permet d'éviter la succession des traitements en proposant un cadre global de résolution de ce problème d'estimation. Dans une première partie, nous proposons une méthode de détection travaillant directement en coordonnées naturelles (polaires) qui exploite les propriétés d'invariance géométrique des objets suivis. Cette solution est ensuite intégrée dans le cadre des approches JPDA et PHD de suivi multicibles résolues grâce aux méthodes de Monte-Carlo séquentielles. La seconde partie du manuscrit vise à s'affranchir du détecteur pour proposer une méthode dans laquelle le modèle d'objet est directement intégré au processus de suivi. C'est sur ce point clé que les avancées ont été les plus significatives permettant d'aboutir à une méthode conjointe de détection et de suivi. Un processus d'agrégation a été développé afin de permettre une formalisation des données qui évite tout prétraitement sous-optimal. Nous avons finalement proposé un formalisme général pour les systèmes multicapteurs (multilidar, centrale inertielle, GPS). D'un point de vue applicatif, ces travaux ont été validés dans le domaine du suivi de véhicules pour les systèmes d'aide à la conduite.
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Shang, Lei, and lei shang@ieee org. "Modelling of Mobile Fading Channels with Fading Mitigation Techniques." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20061222.113303.
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This thesis aims to contribute to the developments of wireless communication systems. The work generally consists of three parts: the first part is a discussion on general digital communication systems, the second part focuses on wireless channel modelling and fading mitigation techniques, and in the third part we discuss the possible application of advanced digital signal processing, especially time-frequency representation and blind source separation, to wireless communication systems. The first part considers general digital communication systems which will be incorporated in later parts. Today's wireless communication system is a subbranch of a general digital communication system that employs various techniques of A/D (Analog to Digital) conversion, source coding, error correction, coding, modulation, and synchronization, signal detection in noise, channel estimation, and equalization. We study and develop the digital communication algorithms to enhance the performance of wireless communication systems. In the Second Part we focus on wireless channel modelling and fading mitigation techniques. A modified Jakes' method is developed for Rayleigh fading channels. We investigate the level-crossing rate (LCR), the average duration of fades (ADF), the probability density function (PDF), the cumulative distribution function (CDF) and the autocorrelation functions (ACF) of this model. The simulated results are verified against the analytical Clarke's channel model. We also construct frequency-selective geometrical-based hyperbolically distributed scatterers (GBHDS) for a macro-cell mobile environment with the proper statistical characteristics. The modified Clarke's model and the GBHDS model may be readily expanded to a MIMO channel model thus we study the MIMO fading channel, specifically we model the MIMO channel in the angular domain. A detailed analysis of Gauss-Markov approximation of the fading channel is also given. Two fading mitigation techniques are investigated: Orthogonal Frequency Division Multiplexing (OFDM) and spatial diversity. In the Third Part, we devote ourselves to the exciting fields of Time-Frequency Analysis and Blind Source Separation and investigate the application of these powerful Digital Signal Processing (DSP) tools to improve the performance of wireless communication systems.
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Zhou, Shuting. "Navigation of a quad-rotor to access the interior of a building." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2237.
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Ce travail de recherche est dédié à l’élaboration d’une stratégie de navigation autonome qui comprend la génération d’une trajectoire optimale en évitant des obstacles, la détection de l’objet d’intérêt spécifique (i.e. une fenêtre) et puis l’exécution de la manoeuvre postérieure à approcher la fenêtre et enfin accéder à l’intérieur du bâtiment. Le véhicule est navigué par un système de vision et une combinaison de capteurs inertiels et d’altitude, ce qui réalise une localisation relative du quadri-rotor par rapport à son environment. Une méthode de planification de trajectoire basée sur Model Predictive Control (MPC), qui utilise les informations fournies par le GPS et le capteur visuel, a été conçue pour générer une trajectoire optimale en temps réel avec des capacités d’évitement de collision, qui commence à partir d’un point initial donné par l’utilisateur et guide le véhicule pour atteindre le point final à l’extérieur du bâtiment de la cible. Dans le but de détecter et de localiser l’objet d’intérêt, deux stratégies de détection d’objet basées sur la vision sont proposées et sont respectivement appliquées dans le système de stéréo vision et le système de vision en utilisant la Kinect. Après l’estimation du modèle de la fenêtre cible, un cadre d’estimation de mouvement est conçu pour estimer ego-mouvement du véhicule à partir des images fournies par le capteur visuel. Il y a eu deux versions des cadres d’estimation de mouvement pour les deux systèmes de vision. Une plate-forme expérimentale de quad-rotor est développée. Pour l’estimation de la dynamique de translation du véhicule, un filtre de Kalman est mis en œuvre pour combiner les capteurs d’imagerie, inertiels et d’altitude. Un système de détection et de contrôle hiérarchique est conçu pour effectuer la navigation et le contrôle de l’hélicoptère quadri-rotor, ce qui permet au véhicule d’estimer l’état sans marques artificielles ou d’autres systèmes de positionnement externesThis research work is dedicated to the development of an autonomous navigation strategy which includes generating an optimal trajectory with obstacles avoiding capabilities, detecting specific object of interest (i.e. a window) and then conducting the subsequent maneuver to approach the window and finally access into the building. The vehicle is navigated by a vision system and a combination of inertial and altitude sensors, which achieve a relative localization of the quad-rotor with respect to its surrounding environment. A MPC-based path planning method using the information provided by the GPS and the visual sensor has been developed to generate an optimal real-time trajectory with collision avoidance capabilities, which starts from an initial point given by the user and guides the vehicle to achieve the final point outside the target building. With the aim of detecting and locating the object of interest, two different vision-based object detection strategies are proposed and are applied respectively in the stereo vision system and the vision system using the Kinect. After estimating the target window model, a motion estimation framework is developed to estimate the vehicle’s ego-motion from the images provided by the visual sensor. There have been two versions of the motion estimation frameworks for both vision systems. A quad-rotor experimental platform is developed. For estimating the translational dynamic of the vehicle, a Kalman filter is implemented to combine the imaging, inertial and altitude sensors. A hierarchical sensing and control system is designed to perform the navigation and control of the quad-rotor helicopter, which allows the vehicle to estimate the state without artificial marks or other external positioning systems
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Xu, Yingchun. "Object tracking in distributed systems." Thesis, 1993. http://hdl.handle.net/2429/2342.
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Object mobility (or process migration) is a very important feature in modern distributed systems. By allowing objects to migrate from one machine to another preemptively, the sys-tem can provide several benefits. These include sharing load, reducing communication cost, increasing availability, and improving invocation performance.
One problem with object mobility is object tracking. Several schemes exist to handle the problem. A forwarding address scheme is used in DEMOS/MP and Emerald. To reduce the number of forwarding messages, DEMOS/MP uses an urgent updating policy to compress the message path. Whenever an object is moved, an updating message is sent to the last node immediately.
In Emerald, a lazy updating policy is adopted. When an object migrates, no updating message is sent. The new location is piggybacked on each reply message. This can also compress the message path for later invocations. The difference between the two is that DEMOS/MP places the cost on object migration while Emerald places the cost on object invocation. They both use the same updating policy for all objects.
We adopt a philosophy in which objects with different behaviors use different updating policies. Objects are divided into two groups: active objects and quiet objects. Active objects are defined as objects which move more often than they are invoked. Quiet objects are invoked more often than they are moved. To optimize object moving and invoking, active objects should use a lazy updating policy while quiet objects should use an urgent updating policy. We call this policy the adaptive updating policy.
The object tracking function is separated from Emerald and implemented as an independent protocol layer, OFP. A reliable datagram protocol, RDP has been designed to support OFP. Experiments are done to validate the protocols' performance. The protocols are implemented on the x-kernel platform.