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1
Alatorre, Sevilla Armando. "Landing of a fixed-wing unmanned aerial vehicle in a limited area". Electronic Thesis or Diss., Compiègne, 2024. http://www.theses.fr/2024COMP2801.
Testo completoAbstract (sommario):
Le projet de thèse consiste à développer une solution pour l'atterrissage d'un drone à voilure fixe de configuration classique dans une zone limitée. Le principal défi consiste à réduire la vitesse de l'avion à une phase minimale pendant le vol, à l'aide d'algorithmes de contrôle automatique. La réduction de la vitesse d'un drone à voilure fixe s'effectue en augmentant son angle d'attaque, ce qui implique un freinage par la force de traînée. Cependant, cette manœuvre est critique pour un avion conventionnel, parce que si son angle d'attaque augmente au-delà de l'angle de décrochage, le véhicule peut perdre sa contrôlabilité, c'est-à-dire qu'il est possible que le véhicule aérien s'effondre et que sa structure soit endommagée. Le modèle mathématique est une représentation d'équations qui décrit le comportement de la dynamique du système. En considérant plusieurs variables pour obtenir une meilleure approximation de la dynamique du système, dans notre cas le véhicule à voilure fixe, la conception des stratégies de contrôle sera plus difficile et plus complexe. Dans ce travail de recherche, nous utiliserons un modèle mathématique non linéaire car les effets de décrochage peuvent être inclus par des approximations mathématiques du moment de tangage, des forces de portance et de traînée. Cela nous permet d'obtenir une meilleure performance des lois de contrôle pour la navigation autonome du drone à voilure fixe. L'une des limites des véhicules à voilure fixe est qu'ils atterrissent dans des espaces de dimensions réduites et que le pourcentage de dommages subis par leur structure est élevé. En outre, les perturbations extérieures et l'inexpérience des pilotes augmentent le risque de dommages. Il est bien connu qu'il est très difficile de satisfaire aux conditions d'une piste d'atterrissage. Par conséquent, la communauté scientifique s'est efforcée de mettre au point des solutions pour l'atterrissage dans des zones limitées. Dans la littérature, on trouve quelques solutions basées sur des véhicules hybrides et des systèmes de récupération. Les véhicules hybrides consistent à modifier la structure d'un véhicule à voilure fixe. Les moteurs sont répartis stratégiquement pour obtenir une configuration de véhicule multirotor, offrant certaines caractéristiques telles que le décollage et l'atterrissage verticaux. Cependant, ces actionneurs augmentent la masse du véhicule, la consommation d'énergie (ce qui réduit la durabilité du vol), la probabilité de défaillance, le coût d'acquisition, de réparation et d'entretien. Notre objectif dans ce travail de recherche est de concevoir et de valider des stratégies de contrôle pour l'atterrissage d'un drone à voilure fixe dans un espace limité. Les stratégies de contrôle ont été conçues selon deux approches : la première est basée sur le développement de manœuvres pour un drone à voilure fixe afin de réduire la vitesse à une phase minimale pendant le vol. Dans la deuxième approche, nous avons travaillé sur les stratégies de contrôle pour l'atterrissage d'un drone à voilure fixe sur un véhicule terrestre en mouvement. Une stratégie de contrôle a été proposée pour réduire la vitesse du drone à voilure fixe au minimum afin d'être capturé par un système de récupération. La stratégie de contrôle a été divisée en trois étapes de vol : dans la première étape, l'avion s'aligne dans le plan x-y tandis qu'il est conduit à une altitude souhaitée pour effectuer un vol de croisière. L'étape suivante consiste en un vol ascendant, axé sur le suivi d'une référence angulaire basée sur une trajectoire phugoïde. Cette trajectoire implique une augmentation de l'angle d'attaque jusqu'à l'angle de décrochage de l'avion. Ainsi, la vitesse aérienne obtient une réduction maximale dans des conditions sûres, permettant au drone d'être capturé par le système de récupération. Toutefois, si le drone n'est pas capturé par le système de récupération, une stratégie de contrôle est appliquée pour rétablir le vol de l'aéronefThe development of this thesis consists of designing some control strategies that allow a fixedwing drone with classical configuration to perform a safe landing in a limited area. The main challenge is to reduce the aircraft’s airspeed avoiding stall conditions. The developed control strategies are focused on two approaches: the first approach consists of the designing airspeed reduction maneuvers for a fixed-wing vehicle to be captured by a recovery system and for a safe landing at a desired coordinate. The next approach is focused on landing a fixed-wing drone on a moving ground vehicle. A dynamic landing trajectory was designed to lead a fixedwing vehicle to the position of a ground vehicle, reaching its position in a defined distance. Moreover, this trajectory was used in a cooperative control design. The control strategy consists of the synchronization of both vehicles to reach the same position at a desired distance. The aerial vehicle tracks the dynamic landing trajectory, and the ground vehicle controls its speed. In addition, we will propose a control architecture with a different focus, where the ground vehicle performs the tracking task of the aerial vehicle’s position in order to be captured. And, the drone’s task is to track a descending flight until the top of the ground vehicle. However, considering the speed difference between both vehicles. Therefore, we propose a new control architecture defining that the aircraft performs an airspeed reduction strategy before beginning its landing stage. The aircraft will navigate to a minimum airspeed, thus, allowing the ground vehicle to reach the fixed-wing drone’s position by increasing its speed. The control laws of each strategy were determined by developing the Lyapunov stability analysis, thus, the stability is guaranteed in each flight stage. Finally, the control strategies were implemented on prototypes allowing us to validate their performance and obtain satisfactory results for safe landing of a fixed-wing drone with classical configuration
2
Hansén, Rasmus, Axel Ringh, Victoria Svedberg e Nils Landin. "Autonomus Helicopter Landing on a Mobile Platform". Thesis, KTH, Optimeringslära och systemteori, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105551.
Testo completoAbstract (sommario):
In this thesis we investigate the problem of landing a helicopter autonomously on a mobile platform by designing controllers for the attitude- and translational dynamics in parallel. A mathematical model of the helicopter, in form of general 6-degrees-of-freedom rigid-body dynamics with application-specific actuations, is developed. A linearized model is used in order to make a landing problem more tractable, which is also rather reasonable under landing constraints, where small angle- and velocity approximations are valid. The inputs used for the attitude controller are the tail rotor thrust and the tip-path-plane angles. Then, a form of cascaded control is adopted for the translational dynamics, in which the inputs are the Euler angles together with the main rotor thrust. The resulting control system is tested by MATLAB simulations against a smooth position reference path, with satisfying results. For the landing scenario, a trajectory planning strategy based on linear model predictive control (MPC) is adopted. The cascaded control system is then used to track the translational reference trajectory. The translational reference trajectory is chosen such that the attitude dynamics is adapted to the attitude of the platform at touch-down.Den här uppsatsen undersöker problemet att autonomt landa en modellhelikopter på en mobil plattform genom att använda olika regulatorer för attityd- och translationsdynamiken. Den matematiska beskrivningen av helikoptern utgår från dynamiken för en stel kropp med 6 frihetsgrader. Eftersom landning kan genomföras med låga hastigheter och små vinklar används en linjär modell för att göra problemet mer lätthanterligt. Insignalerna till systemet är kraften från stjärtrotorn och lutningsvinklarna av huvudrotorns Tip-Path-Plane. En kaskadregulator används för att styra translationssystemet med eulervinklarna och kraften från huvudrotorn, som insignaler. Regulatorn testas i en MATLAB-simulering mot en glatt referensbana med godkända resultat. För landingsproceduren används en banplaneringsstrategi som bygger på linjär prediktiv reglering (PR). Kaskadregulatorn används sedan för att följa translationsreferenserna, vilka blir valda så att även attitydsystemet anpassas efter plattformens attityd i landningsögonblicket.
3
Gising, Andreas. "MALLS - Mobile Automatic Launch and Landing Station for VTOL UAVs". Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15980.
Testo completoAbstract (sommario):
The market for vertical takeoff and landing unmanned aerial vehicles, VTOL UAVs, is growing rapidly. To reciprocate the demand of VTOL UAVs in offshore applications, CybAero has developed a novel concept for landing on moving objects called MALLS, Mobile Automatic Launch and Landing Station. MALLS can tilt its helipad and is supposed to align to either the horizontal plane with an operator adjusted offset or to the helicopter skids. Doing so, eliminates the gyroscopic forces otherwise induced in the rotordisc as the helicopter is forced to change attitude when the skids align to the ground during landing or when standing on a jolting boat with the rotor spun up. This master’s thesis project is an attempt to get the concept of MALLS closer to a quarter scale implementation. The main focus lies on the development of the measurement methods for achieving the references needed by MALLS, the hori- zontal plane and the plane of the helicopter skids. The control of MALLS is also discussed. The measurement methods developed have been proved by tested implementations or simulations. The theories behind them contain among other things signal filtering, Kalman filtering, sensor fusion and search algorithms. The project have led to that the MALLS prototype can align its helipad to the horizontal plane and that a method for measuring the relative attitude between the helipad and the helicopter skids have been developed. Also suggestions for future improvements are presented.
4
Peluchon, Mathias. "Autonomous landing of multicopters on mobile platforms : Design of an autonomous landing solution for multicopters on mobile platforms, based on a ultrasonic local positionning technology". Thesis, KTH, Fordonsdynamik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-261186.
Testo completoAbstract (sommario):
This work studies the use of an ultrasonic 3D positioning system in multicopter landing applications. Its aim is to develop a solution for autonomous landing of rotary wings systems on mobile platforms, especially boat decks using the positioning system developed by the French startup Internest. First, the position sensing algorithms will be improved so as to let them provide accurate relative position measurements in moving reference frames. Then a first implementation of a control algorithm based on PIDs will be considered, discussed and tested. Finally some improvements will be studied, with the use of trajectory planning and feedforward control, as well as the definition of a reference model. The whole work is led in an industrial R&D context, with the aim of developing simple but effective solutions that can easily be used in numerous applications, on a large variety of systems.Det här arbete studerar hur man kan använda 3D positionering med ultraljud för att landa multicenter. Målet är att utveckla en lösning för autonom landning av olika system på mobila plattformar, i synnerhet på båtdäck, med en teknik som utvecklats ett fransk företag, Internest. Först, lägesalgoritmnerna ska förbättras så att de kan ge exakt positionsmätningar i rörliga referensramar. Sedan gjordes en första implementering av lägesalgoritmen med PID som studerades och testades. Till sist, implementerades och och förbättrades algoritmen med banplannering, feedforward reglering, och en referensmodell. Allt detta arbete är genomfört i ett industriellt sammanhang, med målet att utveckla enkla men effektiva lösningar som kan användas i olika applikationer, med olika system.
5
Williams, Christopher G. "Physics-based modeling and assessment of mobile landing platform system design". Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FWilliams.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, September 2008.Thesis Advisor(s): Papoulias, Fotis ; Gordis, Joshua. "September 2008." Description based on title screen as viewed on November 4, 2008 Includes bibliographical references (p. 73-74). Also available in print.
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Stenström, Jonathan. "Simultaneous Trajectory Optimization and Target Estimation Using RSS Measurements to Land a UAV". Thesis, Linköpings universitet, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-131117.
Testo completoAbstract (sommario):
The use of autonomous UAV’s is a progressively expanding industry. This thesisfocuses on the landing procedure with the main goal to be independent of visualaids. That means that the landing site can be hidden from the air, the landingcan be done in bad weather conditions and in the dark. In this thesis the use ofradio signals is investigated as an alternative to the visual sensor based systems.A localization system is needed to perform the landing without knowing wherethe landing site is. In this thesis an Extended Kalman Filter (EKF) is derived andused for the localization, based on the received signal strength from a radio beaconat the landing site. There are two main goals that are included in the landing,to land as accurate and as fast as possible. To combine these two goals a simultaneoustrajectory optimization and target estimation problem is set up that can bepartially solved while flying. The optimal solution to this problem produces thepath that the UAV will travel to get the best target localization while still reachingthe target. It is shown that trying to move directly towards the estimated landingsite is not the best strategy. Instead, the optimal trajectory is a spiral that jointlyoptimizes the information from the sensors and minimizes the arrival time.
7
Lizarraga, Mariano I. "Autonomous landing system for a UAV". Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1655.
Testo completoAbstract (sommario):
Approved for public release, distribution is unlimitedThis thesis is part of an ongoing research conducted at the Naval Postgraduate School to achieve the autonomous shipboard landing of Unmanned Aerial Vehicles (UAV). Two main problems are addressed in this thesis. The first is to establish communication between the UAV's ground station and the Autonomous Landing Flight Control Computer effectively. The second addresses the design and implementation of an autonomous landing controller using classical control techniques. Device drivers for the sensors and the communications protocol were developed in ANSI C. The overall system was implemented in a PC104 computer running a real-time operating system developed by The Mathworks, Inc. Computer and hardware in the loop (HIL) simulation, as well as ground test results show the feasibility of the algorithm proposed here. Flight tests are scheduled to be performed in the near future.
Lieutenant Junior Grade, Mexican Navy
8
Zhao, Honglin, Xianming Zhao e Tingxian Zhou. "Remote Control Multiple Mobile Target System with CDMA". International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611458.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaAt present, multiple mobile targets will be remote controlled in many remote control and telemetry system, in which multiple access technology will be applied. This paper proposes a communication scheme to remote control multiple mobile targets using Coded-Division Multiple Access(CDMA) technique. It's feasibility, advantage and shortcoming are analyzed. Moreover, the key techniques of Direct-Sequence Spread Spectrum(DS/SS) system, i.e. the correlation detection and delay lock-on techniques, are studied and stimulated on the experimental model. The results of theoretical analysis show that the CDMA system has the peculiar advantage over the conventional multiple access system, such as FDMA and TDMA.
9
Barber, D. Blake. "Accurate target geolocation and vision-based landing with application to search and engage missions for miniature air vehicles /". Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1704.pdf.
Testo completo
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Arragattu, Prashanth Kumar. "ISCSI performance for mobile appliances using intermediate target storage". Thesis, Wichita State University, 2009. http://hdl.handle.net/10057/2433.
Testo completoAbstract (sommario):
Looking at the present demand for mobile services we can predict that there will be
an explosive growth in the usage of mobile appliances in the future. But these mobile
appliances suffer from significant problems related to storage restrictions and limited
computing resources. However, the increased demand for mobile services has resulted in
wide spread research to provide remote storage service for mobile appliance using iSCSI.
The iSCSI protocol enables the block level I/O and high-capacity storage service over
general IP networks. But iSCSI, in a client-server environment is very sensitive to latency
(delay time) and when applied to the mobile appliance results in a rapid performance
degradation when the mobile appliance (client) moves far away from the storage server. In
this research, authors describe a new availability remote storage system called an
intermediate storage server, which localizes the iSCSI target to the mobile appliance. Thus,
when the client moves far away from the primary storage server will automatically get
connected to the intermediate storage server rather than trying to establish connection with
the primary storage server. This reduces the latency or delay time involved in contacting and
accessing the resources from the storage server.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering
11
Balmer, Georg Robert. "Modelling and Control of a Fixed-wing UAV for Landings on Mobile Landing Platforms". Thesis, KTH, Optimeringslära och systemteori, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176881.
Testo completoAbstract (sommario):
Landing on mobile landing platforms could eliminate the need for landing gear. This would particularly benefit high altitude solar UAV, which typically have a very limited payload. Such landings would however require a precise and decoupled control of the UAV’s altitude and speed. In this thesis, a small UAV is modelled, and a flight control system suitable for such landings is developed. The aerodynamic properties of the UAV were estimated using the vortex lattice method. Propeller performance data was obtained from the manufacturer and used in the propulsion model. The complete UAV model was validated using data from test flights. A comparison of period and damping of the dynamic modes showed a good agreement (<10% error) with the flight data, except for the phugoid damping, which was too low in the model. The model was used to design two flight control systems, one consisting of three SISO loops for altitude, airspeed and course; and another using a TECS-based controller for airspeed and altitude. Extensive testing in simulation and flight revealed a superior performance of the TECS-based controller, especially in the ability to decouple altitude and airspeed responses.Landningar på mobila plattformar skulle kunna avlägsna behovet av landställ. Detta skulle vara särskilt gynnsamt för högflygande solkraftsdrivna obemannade flygplan, som oftast har en mycket begränsad lastmöjlighet. En sådan landning skulle kräva en mycket noggrann och frikopplad reglering av planets höjd och hastighet. I detta examensarbete har ett litet obemannat flygplan modellerats och ett reglersystem passande för denna typ av landning har utvecklats. De aerodynamiska egenskaperna hos det obemannade flygplanet har uppskattats genom VLM (Vortex Lattice Method). Prestandadata för propellrarna givet från tillverkaren har använts i modelleringen av framdrivningssystemet. Modellen för flygplanet har validerats med data från flygtester, och en jämförelse av perioder och dämpning av de dynamiska moderna visar på en bra överensstämmelse med flygdatan (<10% fel), utom för phugoiddämpningen som var för liten i modellen jämfört med flygtesterna. Modellen har använts för att skapa två reglersystem; ett bestående av tre SISO-kretsar för höjd, hastighet och kurs, och en TECS-baserad regulator för hastighet och höjd. Omfattande simulerings- och flygtester visar att den TECS-baserade regulatorns prestation överträ˙ar den SISO-kretsbaserade, framför allt i förmågan att frikopplade höjd- och hastighetssvar.
12
Lusk, Parker Chase. "Vision-Based Emergency Landing of Small Unmanned Aircraft Systems". BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7029.
Testo completoAbstract (sommario):
Emergency landing is a critical safety mechanism for aerial vehicles. Commercial aircraft have triply-redundant systems that greatly increase the probability that the pilot will be able to land the aircraft at a designated airfield in the event of an emergency. In general aviation, the chances of always reaching a designated airfield are lower, but the successful pilot might use landmarks and other visual information to safely land in unprepared locations. For small unmanned aircraft systems (sUAS), triply- or even doubly-redundant systems are unlikely due to size, weight, and power constraints. Additionally, there is a growing demand for beyond visual line of sight (BVLOS) operations, where an sUAS operator would be unable to guide the vehicle safely to the ground. This thesis presents a machine vision-based approach to emergency landing for small unmanned aircraft systems. In the event of an emergency, the vehicle uses a pre-compiled database of potential landing sites to select the most accessible location to land based on vehicle health. Because it is impossible to know the current state of any ground environment, a camera is used for real-time visual feedback. Using the recently developed Recursive-RANSAC algorithm, an arbitrary number of moving ground obstacles can be visually detected and tracked. If obstacles are present in the selected ditch site, the emergency landing system chooses a new ditch site to mitigate risk. This system is called Safe2Ditch.
13
Wessén, Fredrik, e Mats Forsberg. "On Target Marketing in Mobile Devices : MBA-thesis in marketing". Thesis, University of Gävle, University of Gävle, Ämnesavdelningen för företagsekonomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-6321.
Testo completoAbstract (sommario):
In the best of worlds, all marketing is relevant.
This study brings light to and creates understanding for how to capture the opportunities for target marketing, given by resent technical development and improvement.
Customers often perceive marketing on the internet as annoying, embarrassing, repetitive and sometimes even noisy. Companies have problems to focus their marketing efforts towards the areas which give most value for the marketing investments. The conflict between companies pushing the marketing messages to their customers, who are trying to avoid them, a growing mistrust is feed.
Well established businesses are challenged by new companies cutting in between the content providers and their customers. A new business model using the Long Tail phenomena is shaking the old media houses’ business position.
Smartphones and netbooks are merging into mobile devices, which release a number of opportunities for target marketing. This study states that mobile devices are personalized and as a consequence, open for the possibility of target marketing towards individuals. However, there are identified obstacles to overcome. One challenge lies in the balance between marketing benefits and preventing violation of the customers’ personal integrity.
From literature and case studies, light is brought to the state of practice of rules and regulations, old media houses Schibsted and Aftonbladet, search engine provider as Google and a marketing agency, Mobiento Mobile Marketing.
Trends and best practices stick out as more important in order for a company to become a successful target marketing actor. A “target marketing house concept” points out four significant areas for companies to benefit from the power of target marketing in mobile devices.
Trough out of this study, protection of the personal integrity and personal data has been pointed out as a key factor for a mutual and trustful customer relationship. This is considered to be as a precondition, both for behaviour segmentation and for a joint rewarding customer dialogue.
14
Barber, Duncan B. "Accurate Target Geolocation and Vision-Based Landing with Application to Search and Engage Missions for Miniature Air Vehicles". BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1313.
Testo completoAbstract (sommario):
Miniature air vehicles (MAVs) have attracted a large amount of interest recently both from the research community and from the public. New battery technologies as well as rapid developments in embedded processing and MEMS sensor technologies have greatly increased the potential of these vehicles. MAVs have been envisioned playing significant roles in both civil and military applications. Examples include: fire monitoring, search and rescue, traffic monitoring, crop monitoring, convoy protection, border surveillance, troop support, law enforcement, natural disaster relief, and aerial photography. The application of MAVs tends to center on the ability of the MAV to collect and deliver visual information to the user. In many applications it is important to be able to accurately geolocate items of interest in the visual data. However, the inaccuracies associated with MAV platforms have led to relatively large errors in previous attempts at geolocation. The first half of this thesis focuses on increasing the accuracy of geolocation estimates achievable using a hand-launchable MAV. To accomplish this, methods are presented for bias estimation, wind estimation, recursive least squares filtering, and optimal flight path generation. Hardware results are presented which demonstrate the ability to consistently localize targets to within 5 m regardless of wind conditions. The second half of this thesis focuses on using the high accuracy geolocation estimates to complete a search and engage mission. This is a mission in which the MAV not only locates the target, but also accurately delivers a payload to the target site. The focus is on delivering an attached payload via accurate landing at the target site. A vision-based landing approach is presented which is robust to both wind and moving targets. Simulation results are presented which demonstrate the effectiveness of the control.
15
Tang, Zhijun. "Information-theoretic management of mobile sensor agents". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1126882086.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xiii, 170 p.; also includes graphics (some col.). Includes bibliographical references (p. 162-170). Available online via OhioLINK's ETD Center
16
Arik, Muharrem. "Collaborative Mobile Target Imaging In Ultra-wideband Wireless Radar Sensor Networks". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610145/index.pdf.
Testo completoAbstract (sommario):
Wireless sensor networks (WSN) have thus far been used for detection and tracking of static and mobile targets for surveillance and security applications. However, detection and tracking do not suffice for a complete satisfaction of these applications and an accurate target classification. To address this need, among various target classification methods, imaging of target yields the most valuable information. Nevertheless, imaging of mobile targets moving over an area requires networked and collaborative detection, tracking and imaging capabilities. With this regard, ultra-wideband (UWB) radar technology stands as a promising approach for networked target imaging over an area due to its unique features such as having no line-of-sight (LoS). However, the UWB wireless radar sensor network (WRSN) is yet to be developed for high quality imaging of mobile targets.
In this thesis, an architecture for UWB wireless radar sensor network and a new collaborative mobile target imaging (CMTI) algorithm for UWB wireless radar sensor networks (WRSN) are presented. It is intended to accurately and efficiently obtain an image of mobile targets based on the collaborative eort of deployed UWB wireless radar sensor nodes. CMTI enables detection, tracking and imaging of mobile targets with a complete WRSN solution. CMTI exploits mobility of the target in the sensor field to build its own multi-static radar aperture. Performance evaluations reveal that CMTI obtains high quality radar image of mobile targets in WRSN with very low communication overhead and energy expenditure.
17
Adams, Martin David. "Optical range data analysis for stable target pursuit in mobile robotics". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305510.
Testo completo
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Wahlberg, Fredrik. "Parallel algorithms for target tracking on multi-coreplatform with mobile LEGO robots". Thesis, Uppsala universitet, Avdelningen för systemteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-155537.
Testo completoAbstract (sommario):
The aim of this master thesis was to develop a versatile and reliable experimentalplatform of mobile robots, solving tracking problems, for education and research.Evaluation of parallel bearings-only tracking and control algorithms on a multi-corearchitecture has been performed. The platform was implemented as a mobile wirelesssensor network using multiple mobile robots, each using a mounted camera for dataacquisition. Data processing was performed on the mobile robots and on a server,which also played the role of network communication hub. A major focus was toimplement this platform in a flexible manner to allow for education and futureresearch in the fields of signal processing, wireless sensor networks and automaticcontrol. The implemented platform was intended to act as a bridge between the idealworld of simulation and the non-ideal real world of full scale prototypes.The implemented algorithms did estimation of the positions of the robots, estimationof a non-cooperating target's position and regulating the positions of the robots. Thetracking algorithms implemented were the Gaussian particle filter, the globallydistributed particle filter and the locally distributed particle filter. The regulator triedto move the robots to give the highest possible sensor information under givenconstraints. The regulators implemented used model predictive control algorithms.Code for communicating with filters in external processes were implementedtogether with tools for data extraction and statistical analysis.Both implementation details and evaluation of different tracking algorithms arepresented. Some algorithms have been tested as examples of the platformscapabilities, among them scalability and accuracy of some particle filtering techniques.The filters performed with sufficient accuracy and showed a close to linear speedupusing up to 12 processor cores. Performance of parallel particle filtering withconstraints on network bandwidth was also studied, measuring breakpoints on filtercommunication to avoid weight starvation. Quality of the sensor readings, networklatency and hardware performance are discussed. Experiments showed that theplatform was a viable alternative for data acquisition in algorithm development and forbenchmarking to multi-core architecture. The platform was shown to be flexibleenough to be used a framework for future algorithm development and education inautomatic control.
19
Ahola, N. (Nancy). "International new ventures’ use of networks to target globally released mobile applications". Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201406101727.
Testo completoAbstract (sommario):
In this paper, the study will deal with the theoretical basis of internationalization of New Ventures and the importance of networks to acquire the knowledge to develop mobile application products on a global level. It will weigh the different uses of networks for market entry for SMEs that have a lack of capital, both human and financial. The study will also look at mobile applications themselves and the business models they currently have as options to create their new ventures.
While many mobile app and technology companies look to globally release their mobile applications with the same approach without any change or localization, all consumers do not subscribe to the same buying tastes in every region. Taking into consideration buying patterns and regional differences, examination of the product positioning and applying this thought process to technology and how each company’s approach succeeded or failed.
In this paper, the focus will be examining several views: The idea of a globally released mobile application by a company, developed with the thought that the idea is so universal that it will succeed in every market, or the concept that even in the mobile application development area, that each “product” will need to be customized for certain markets for a more successful market entry.
Some other aspects of this paper will take a look at technology itself, both Mobile Applications and the Internet, as methods of market entry. With these technologies available to international new ventures, which do not have the financial capital to commit to internationalize.
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Chen, Yifeng. "Control of a flexible space robot tracking a moving target". Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39725.
Testo completo
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Singh, Bal Baljinder. "Cooperative target tracking for heterogeneous robots". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Cerca il testo completoAbstract (sommario):
This work deals with the motion planning of multiple robotic agents that, equipped with sensors with limited field of views, have the task of tracking an unknown target. A Nonlinear Model Predictive Control strategy is used to minimize the entropy of the estimation of the target’s state provided by an intermittent measurement Kalman filter. The scheme is validated by first implementing the controller on a team of robots comprised of an aerial and a ground vehicle, modelled with double-integrator dynamics in Matlab-Simulink. Then, by using the same NMPC scheme as a trajectory generator, the aerial vehicle is modelled as a quadrotor UAV following with a low-level controller the high-level planner’s trajectories, while tracking the target, another quadrotor UAV. To do so, the Matlab-Simulink simulations are coupled with Gazebo, a 3D dynamic simulator, and Genom, a tool for real-time software architectures.
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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.
Testo completoAbstract (sommario):
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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Barbieri, Nicholas P. "Aircraft position estimation using lenticular sheet generated optical patterns". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22612.
Testo completo
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Bourdaud, Pierre. "Impact of a landing obligation on coupled dynamics ecosystem-fishers : individual-based modelling approach applied to Eastern English Channel". Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0474/document.
Testo completoAbstract (sommario):
L'objectif de cette thèse était d'anticiper les effets de l'Obligation de Débarquement (OD) mise en place en UE depuis début 2015 en Manche Orientale (MO). Pour accomplir ces objectifs, il a été prévu de : i) mieux comprendre la distribution spatiale saisonnière d'espèces commerciales à l'aide d'observations embarquées sur des navires commerciaux, ii) les comparer avec la distribution de l'effort de pêche à fine échelle des chalutiers de fonds (OTB), et iii) développer un modèle individu-centré de dynamique des flotilles, DSVM, à intégrer avec le modèle écosystémique OSMOSE pour simuler l'OD. L'utilité des données d'observations embarquées a été prouvée pour une majeure partie des espèces échantillonnées, en utilisant une validation par la bibliographie et un indicateur géostatique. Ensuite la comparaison de l'effort de pêche à fine échelle a fourni une amélioration de la quantification de l'effort de pêche effectif et mis en valeur l'importance de la seiche et du rouget barbet pour la distribution des OTB en MO. De plus, l'intensité de ciblage des OTB a été quantifiée en octobre à l'aide d'un nouvel indicateur, et démontré l'intérêt pour les mêmes espèces, mais aussi la contrainte d'un faible quota de cabillaud pour les pêcheurs. Les résultats du couplage OSMOSE-DSVM montrent que k'OD aurait des effets négatifs à court terme pour le revenu des pêcheurs, induits par le déplacement de l'effort de pêche afin d'éviter les dépassements de quota, mais serait profitable à moyen terme. Cependant, l'OD provoquerait une hausse de la pression de prédation produite par le cabillaud et le merlan sur les autres espèces, ce qui n'améliorerait pas l'état global de l'écosystèmeThe objective of this thesis was to anticipate the effects if the EU Landing Obligation (LO) implemented since the beginning of 2015 in the Eastern English Channel (EEC). To achieve these objectives, it was planned to : i) better understand seasonal spatial distribution of commercial species using on-board commercial vessels observation data, ii) compare them with the final scale fishing effort distribution of EEC bottom otter trawlers (OTB), and iii) develop an individual-based model of fleet-dynamics, DSVM, to be integrated within the ecosystem model OSMOSE to simulate a LO. The usefulness of on-board observation data was proved for a main part of a species sample, using validation from the literature and a geostatistical indicator. Then the comparison of fine scale fishing effort provided an improvement of the quantification of effective fishing effort and emphasized the importance of cuttlefish and red mullet for the global distribution of EEC OTB. In addition, the targeting intensity of OTB was quantified in October using a newly-developed indicator, and demonstrated the attractiveness of the same species, but also the constraint of low cod quota for fishers. Results of the OSMOSE-DSVM coupling show that the LO would have short-term negative effects on fishers' revenue, induced by a large reallocation of their fishing effort to avoid quota over-shooting, but would be profitable in the medium-term. However, the LO would induce an increase of the predatory pressure operated by cod and withing on the other species, which would not improve the overall ecosystem health
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Boulanouar, Ibtissem. "Algorithmes de suivi de cible mobile pour les réseaux de capteurs sans fils". Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1077/document.
Testo completoAbstract (sommario):
Les réseaux de capteurs sans fils se définissent comme un ensemble de petits appareils autonomes et interconnectés. Ces capteurs sont déployés dans une zone d'intérêt dans le but de collecter des informations de l'environnement comme la température ou la qualité de l'air, suivant l'application envisagée. L'évolution de ces dispositifs de capture vers le multimédia ouvre l'accès à une plus large palette d'applications et de services pour une meilleure maitrise de notre environnement. Dans cette thèse nous nous intéressons au suivi de cible mobile dans les réseaux de capteurs sans fils, certains de ces capteurs pouvant collecter des images. Le suivi de cible (Tracking) consiste à détecter et à localiser sur l'ensemble de sa trajectoire une cible traversant une zone d'intérêt. Cette application peut s'avérer très utile, par exemple, pour détecter et enregistrer les déplacements d'un intrus dans une zone sensible ou encore pour suivre les déplacements d'une personne assistée et munie d'un appareil avec interface radio. Contrairement aux systèmes de surveillance classiques qui nécessitent une infrastructure fixe, les réseaux de capteurs sans fils sont aussi faciles à installer qu'à désinstaller. De plus, grâce à leur polyvalence, ils peuvent être utilisés dans de nombreux environnements hostiles et inaccessibles pour l'être humain. Toutefois, étant restreints en énergie, ils ne peuvent rester actifs en permanence au risque de limiter considérablement leur durée de vie. Afin de résoudre ce problème, l'idée est d'activer uniquement les capteurs qui sont sur la trajectoire de la cible au moment ou cette dernière est à leur portée radio ou visuelle. La question est donc : comment et sur quels critères activer ces capteurs afin d'obtenir à tout moment le meilleur compromis entre la précision du suivi et la préservation des ressources énergétiques ? C'est à cette question que nous essayerons de répondre tout au long de cette thèse. Dans un premier temps nous nous intéressons aux cibles communicantes qui ont la faculté d'émettre des signaux et donc de faciliter grandement le processus de suivi. Le défi ici est de relayer l'information entre les différents capteurs concernés. Nous utilisons pour cela un algorithme de déploiement basé sur le concept de forces virtuelles (VFA : Virtual Forces Algorithm) associé à un algorithme de suivi collaboratif et distribué implémenté sur un réseau organisé en clusters. Ensuite, nous traitons le cas, plus complexe et plus fréquent, des cibles non communicantes. L'objectif est de détecter la présence de la cible uniquement à l'aide de capteurs de présence. Pour cela nous proposons le déploiement d'un réseau de capteurs sans fil hétérogènes composé decapteurs de mouvement en charge de la partie détection de la cible et de capteurs vidéo en charge de la partie localisation. Lorsqu'une cible est détectée par un capteur de mouvement, l'information est communiquée aux capteurs vidéo voisins qui décident d'activer ou non leurs caméras en se basant sur des critères prédéfinis tenant compte de l'angle d'orientation des caméras. Enfin, dans une dernière contribution nous nous intéressons plus spécifique mentaux modèles de mobilité de la cible. Ces modèles nous permettent d'anticiper ses déplacements et d'affiner le processus d'activation des capteurs qui sont sur sa trajectoire. Nous utilisons pour cela le filtre de Kalman étendu combiné à un mécanisme de détection de changements de direction nommé CuSum (Cumulative Summuray). Ce mécanisme nous permet de calculer efficacement les futures coordonnées de la cible et de réveiller les capteurs en conséquenceWireless Sensor Networks (WSN) are a set of tiny autonomous and interconnected devices. These Sensors are scattered in a region of interest to collect information about the surrounding environment depending on the intended application. Nowadays, sensors allow handling more complex data such as multimedia flow. Thus, we observe the emergence of Wireless Multimedia Sensor Networks opening a wider range of applications. In this work, we focus on tracking moving target in these kinds of networks. Target tracking is defined as a two-stage application: detection and localization of the target through its evolution inside an area of interest. This application can be very useful. For example, the presence of an intruder can be detected and its position inside a sensitive area reported, elderly or sick persons carrying sensors can be tracked anytime and so on. Unlike classical monitoring systems, WSN are more flexible and more easy to set up. Moreover, due to their versatility and autonomy they can be used in hostile regions, inaccessible for human. However, these kinds of networks have some limitations: wireless links are not reliable and data processing and transmission are greedy processes in term of energy. To overcome the energy constraint, only the sensors located in target pathway should be activated. Thus, the question is : how to select these sensors to obtain the best compromise between the tracking precision and the energy consumption? This is the question we are trying to answer in this dissertation. Firstly, we focus on communicating targets which have the ability to transmit signals and greatly facilitate the tracking process. The challenge here is to relay the information between the concerned sensors. In order to deal with this challenge, we use a deployment strategy based on virtual forces (VFA: Virtual Forces Algorithm) associated to a distributed tracking algorithm implemented in a cluster-based network. Secondly, we handle a more complex and more frequent case of non-communicating targets. The objective is to detect the presence of such target using movement sensors. We propose the deployment of an heterogeneous wireless sensor networks composed of movement sensors used to detect the target and camera sensors used to locate it. When the target is detected the information is sent to the camera sensors which decide whether to activate or not their cameras based on probabilistic criteria which include the camera orientation angle. Finally, as our last contribution, we specifically focus on target mobility models. These models help us to predict target behaviour and refine the sensor activation process. We use the Extended Kalamn filter as prediction model combined with a change detection mechanism named CuSum (Cumulative Summuray). This mechanism allows to efficiently compute the future target coordinates, and to select which sensors to activate
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Poli, Maria Esmeralda Ramos. "Definição do volume de planejamento do alvo (PTV) e seu efeito na radioterapia". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-27112007-144824/.
Testo completoAbstract (sommario):
Este trabalho visa estudar as margens necessárias para definir o volume de planejamento do alvo (PTV) requeridas para tratar adequadamente tumores móveis como os localizados na próstata ou tumores localizados em áreas com pouca mobilidade como os da região da cabeça e pescoço, na ausência de localização do alvo por imagem. Também tem como objetivo avaliar o impacto causado pelo PTV, em termos de dose, nas estruturas críticas ao seu redor e sua influência quando planejamento inverso é utilizado na radioterapia com modulação de feixe (IMRT). Dados de 387 pacientes de próstata foram analizados retrospectivamente. Todos os pacientes receberam localização pré-tratamento com ultra-som 2D resultando em 10.327 localizações, cada uma com deslocamento de isocentro em três direções: antero-posterior (AP), lateral direitaesquerda (DE), e superior-inferior (SI). O deslocamento médio e desvio padrão (SD) para cada direção foi estimado a partir dos dados de tratamento gravados diariamente. As incertezas (SD) na posição do alvo foram 4,4 mm (AP), 3,6 mm (DE), e 4,5 mm (SI). O estudo das incertezas no posicionamento diário de 78 pacientes com tumores de cabeça e pescoço que utilizaram máscaras termoplásticas como imobilizadores, avaliados com equipamento de portal com imagem eletrônica (EPID), mostrou variações (SD) na posição do isocentro de tratamento de 3,1 mm (AP), 1,5 mm (DE), 4,5 mm (SI). Aplicando estes desvios num simulador antropomórfico estudou-se os histogramas de dose-volume resultantes do deslocamento do isocentro no tratamento diário. Os resultados mostraram a importância de se colocar margens no volume clínico do alvo para garantir um tratamento adequado e também mostraram que a variação diária do isocentro de tratamento pode causar um aumento de dose maior que o nível de tolerância dos órgãos críticos.This work intends to study the margins required to define a planning target volume (PTV) for adequate treatment of the mobile tumors such as prostate or those located in areas with less mobility as the ones in head and neck region, in the absence of daily localization imaging based. It is also intends to evaluate the impact caused by the PTV, in terms of dose, to the critical structures surrounding the PTV and its influence when inverse planning is used in the intensity-modulated radiation therapy (IMRT). Data from 387 prostate patients were analyzed retrospectively. Every patient in the study received daily pre-treatment localization with 2D ultrasound resulting in a total of 10,327 localizations, each comprising of an isocenter displacement in 3 directions: anterior-posterior (AP), right-left lateral (RL), and superior-inferior (SI). The mean displacement and standard deviation (SD) for each direction for each patient was computed from daily treatment records. The uncertainties (SD) in the target position were 4.4 mm (AP), 3.6 mm (RL), and 4.5 mm (SI). A study of the uncertainties in the daily positioning of 78 head and neck patients who used thermoplastic mask to immobilize them, evaluated with electronic portal imaging device (EPID), showed variations (SD) in the isocenter treatment position of 3.1 mm (AP), 1.5 mm (RL), and 4.5 mm (SI). By applying these shifts in an anthropomorphic phantom it was studied the dose-volume histograms resultant of the isocenter displacement in the daily treatment. The result showed the importance of putting margins in the clinical target volume to assure an adequate treatment and also showed that isocenter daily variation can cause an increase to the dose greater than the tolerance level to the critical organs.
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Conte, Gianpaolo. "Vision-Based Localization and Guidance for Unmanned Aerial Vehicles". Doctoral thesis, Linköping : Department of of Computer and Information Science, Linköpings universitet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17767.
Testo completo
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Barth, Jens [Verfasser], Björn Gutachter] Eskofier, Kamiar [Gutachter] [Aminian e Jochen [Gutachter] Klucken. "Development and Validation of a Mobile Gait Analysis System Providing Clinically Relevant Target Parameters in Parkinson's Disease / Jens Gerhard Barth ; Gutachter: Björn Eskofier, Kamiar Aminian, Jochen Klucken". Erlangen : FAU University Press, 2017. http://nbn-resolving.de/urn:nbn:de:bvb:29-opus4-93274.
Testo completo
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Barth, Jens Gerhard Verfasser], Björn [Gutachter] Eskofier, Kamiar [Gutachter] [Aminian e Jochen [Gutachter] Klucken. "Development and Validation of a Mobile Gait Analysis System Providing Clinically Relevant Target Parameters in Parkinson's Disease / Jens Gerhard Barth ; Gutachter: Björn Eskofier, Kamiar Aminian, Jochen Klucken". Erlangen : FAU University Press, 2017. http://d-nb.info/1151399795/34.
Testo completo
30
Barth, Jens Gerhard [Verfasser], Björn [Gutachter] Eskofier, Kamiar [Gutachter] Aminian e Jochen [Gutachter] Klucken. "Development and Validation of a Mobile Gait Analysis System Providing Clinically Relevant Target Parameters in Parkinson's Disease / Jens Gerhard Barth ; Gutachter: Björn Eskofier, Kamiar Aminian, Jochen Klucken". Erlangen : FAU University Press, 2017. http://d-nb.info/1151399795/34.
Testo completo
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Sohal, Shubhdildeep Singh. "A Hybrid Tracking Approach for Autonomous Docking in Self-Reconfigurable Robotic Modules". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90889.
Testo completoAbstract (sommario):
Active docking in modular robotic systems has received a lot of interest recently as it allows small versatile robotic systems to coalesce and achieve the structural benefits of larger robotic systems. This feature enables reconfigurable modular robotic systems to bridge the gap between small agile systems and larger robotic systems. The proposed self-reconfigurable mobile robot design exhibits dual mobility using a tracked drive for longitudinal locomotion and wheeled drive for lateral locomotion. The two degrees of freedom (DOF) docking interface referred to as GHEFT (Genderless, High strength, Efficient, Fail-Safe, high misalignment Tolerant) allows for an efficient docking while tolerating misalignments in 6-DOF. In addition, motion along the vertical axis is also achieved via an additional translational DOF, allowing for toggling between tracked and wheeled locomotion modes by lowering and raising the wheeled assembly. This thesis also presents a visual-based onboard Hybrid Target Tracking algorithm to detect and follow a target robot leading to autonomous docking between the modules. As a result of this proposed approach, the tracked features are then used to bring the robots in sufficient proximity for the docking procedure using Image Based Visual Servoing (IBVS) control. Experimental results to validate the robustness of the proposed tracking method, as well as the reliability of the autonomous docking procedure, are also presented in this thesis.Master of Science
Active docking in modular robotic systems has received a lot of interest recently as it allows small versatile robotic systems to coalesce and achieve the structural benefits of larger robotic systems. This feature enables reconfigurable modular robotic systems to bridge the gap between small agile systems and larger robotic systems. Such robots can prove useful in environments that are either too dangerous or inaccessible to humans. Therefore, in this research, several specific hardware and software development aspects related to self-reconfigurable mobile robots are proposed. In terms of hardware development, a robotic module was designed that is symmetrically invertible and exhibits dual mobility using a tracked drive for longitudinal locomotion and wheeled drive for lateral locomotion. Such interchangeable mobility is important when the robot operates in a constrained workspace. The mobile robot also has integrated two degrees of freedom (DOF) docking mechanisms referred to as GHEFT (Genderless, High strength, Efficient, Fail-Safe, high misalignment Tolerant). The docking interface allows for an efficient docking while tolerating misalignments in 6-DOF. In addition, motion along the vertical axis is also performed via an additional translational DOF, allowing for lowering and raising the wheeled assembly. The robot is equipped with sensors to provide positional feedback of the joints relative to the target robot. In terms of software development, a visual-based onboard Hybrid Target Tracking algorithm for high-speed consistent tracking iv of colored targets is also presented in this work. The proposed technique is used to detect and follow a colored target attached to the target robot leading to autonomous docking between the modules using Image Based Visual Servoing (IBVS). Experimental results to validate the robustness of the proposed tracking approach, as well as the reliability of the autonomous docking procedure, are also presented in the thesis. The thesis is concluded with discussions about future research in both structured and unstructured terrains.
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Chen, Yu-Yi, e 陳佑逸. "Deadline-Constrained Mobile Target Detection in Mobile SensorNetworks". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/71541624027050241019.
Testo completoAbstract (sommario):
碩士國立臺灣大學
資訊網路與多媒體研究所
99
Wireless sensor networks have been widely studied in arious applications such as environmental monitoring , battlefield surveillance, and intrusion detection recently. One of the important applications is to detect mobile targets (e.g., invaders) by using mobile sensor nodes. Consider a closed region where there are several mobile sensors patrolling the area and some mobile targets in the region. The mobile sensors need to find the targets before a time period because the mobile targets may escape from the monitored region after a certain period of time. In order to meet the deadline, many mobile sensors should be deployed to reduce the detection time. This work aims at finding the number of sensors required in the region through realizing relations among expected detection time, detection strategies, and the number of sensors. Thus, given the number of sensors and detecting robability, we propose a Markov model to derive the expected detection time. Our proposed model can then help determine how many sensors are sufficient such that sensors are able to detect the targets before a given deadline. We also provided a cooperative scheme for sensors that can reduce expected detection time and a distributed protocol for sensors with limited transmission range. The simulation results show that the model can predict the expected detection time precisely, and the number of sensors required derived from the model is adequate.
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Chen, Tong-Bore, e 陳棟柏. "Tracking Target Using Mobile Sensors". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/21703556394290412979.
Testo completoAbstract (sommario):
碩士國立高雄第一科技大學
電腦與通訊工程所
97
Traditional tracking method estimated target trajectory with the data measured by stationary sensors. This method referred to as the static tracking commonly use finite sensors randomly deployed in a guarding zone. Since each sensor has a limited guarding area, the use of finite sensors usually can not cover the whole guarding zone. Some blind areas will exist and degrade the performance of static tracking. In the thesis, we propose a dynamic tracking method that uses mobile sensors with some restrictions. The state of the target and sensors are modeled by system, the target is assumed a linear Gaussian model and the measurements are assumed a non-linear model with Gaussian noise, and impaired by Gaussian noise. Extended Kalman filtering (EKF) technology is used to estimate the predicted Mean Square Error (MSE) of the estimated target state. The purpose of this approach find out the optimal sensor movement and the sensor scheduling sequence in order to minimize the predict estimation error, and satisfied the system constraints. The simulation results show that this approach is superior to the static tracking in both accuracy and reliability.
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Ahmadi, Ali. "Improving UAV autonomous landing on target using combination of FAST & SURF". Master's thesis, 2019. http://hdl.handle.net/10316/93132.
Testo completoAbstract (sommario):
Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeirosUAVs are being one of the most interesting and useful topics during past years and it has high scientific value and high potential for military and discovery issues. Many research labs around the world have been developing their UAVs for military and civilian, surveillance, construction, rescue, exploration and etc. Also, UAV usage in many factories, hospitals, hotels and industrial area is growing. The challenging task among the AI is optimization of navigating UAV in the arbitrary environment including obstacle avoidance. In order to land on a platform, there are approaches like graph based and geometric estimation. Time complexity in geometric approaches would increase when the degree of freedom (DOF) is increasing. Thus geometric approaches are useful in less DOF systems. To obtain this purpose, using several approaches based on image processing, artificial intelligence and machine learning has recommended. So that these approaches generally are evaluated with the speed and precision of finding the objects. Therefor they will guarantee finding the best way of navigation and performing precision landing on landing platform. In this thesis, we’ve presented a novel method based on combination of FAST and SURF, which is an efficient solution in order to detect the object and performing the precision landing on it. First of all, we design the system and necessary equipment, then in order to reduce the color dimension and segmentation of the image, an algorithm is presented and developed. Finally, in order to perform object detection and autonomous precision landing, the combination of algorithms is introduced. According to the results from the simulation of the purposed solution and evaluations, the purposed solution has performed better than the similar solutions. In comparison with the fastest solution, which is ORB, the processing speed improved 16.8% and in comparison, with the most precise solution, which is SIFT, the processing speed improved 82.3%.
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Lee, Hui-En, e 李慧恩. "Target Tracking of Autonomous Mobile Robots". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/68725262347106353525.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
自動化及控制研究所
98
In recent years, autonomous mobile robot has become an important and popular research topic. It is widely used in service robot and security robot, etc. Visual tracking is also a popular topic of research and development. It is applied in security monitoring system and home care system, etc. The conventional visual tracking system applies the fixed camera as the sensor. The drawback is once the target out of the sensing area, the system won’t be able to track the target. This research adopt PTZ (Pan/ tilt/zoom) CCD camera to develop a dynamic tracking system which the camera can be rotated according to the orientation of the moving target, and expand the area of tracking in real-time. Furthermore, the proposed tracking methodologies command the autonomous mobile robot to follow the moving object and keep in the line of sight. This thesis detects the moving object based on the Bayes' theorem background modeling method and applies color based Particle filter to track the centroid of moving object. The visual tracking system calculates the relative angle of moving object and the autonomous mobile robot. According to this angle, the autonomous mobile robot tracks the moving object. This thesis uses eight ultrasonic sensors to detect distance of obstacles. Autonomous mobile robot with intelligent obstacle avoidance controller follows, tracks moving object and avoids hitting the other obstacles. The accuracy of center point of tracking results and the real target are more than 80%. The experiments proved that this approach can achieve real-time tracking system.
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Yeah, Chia-Wei, e 葉家瑋. "Visual Servo Control Based Autonomous Landing System for Aerial Mobile Robot". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/17269145498363339357.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
自動化及控制研究所
103
In recent years, the aerial mobile robots have rapid development and application. Especially in environment detection, relief disaster and sea rescue etc. However, the aerial mobile robot can only execute the environment detection in high altitude, in the low altitude cannot obtain global information. This thesis proposed cooperate operation concept between two of different altitude aerial mobile robots. The high altitude robot provides visual global navigation. The low altitude robots according to global navigation information fly and land on helipad autonomously. The autonomous landing control is based on fuzzy logic control and neural network to improve control performance. The ground control station obtains all of the information and send control commend which can achieve efficacy of wireless control. The experiment analysis is based on three parts which are vision global navigation system of high altitude robot, autonomous landing system of low altitude robot and two aerial robots cooperate operation. The autonomous landing error of low altitude robot is 6.53 cm; the locking rate in indoor environment is 82.88%. The landing error in outdoor environment is 65.33 cm and the locking rate is 54.08%. The visual global navigation system of high altitude robot success rate is 42.8% in indoor environment, in outdoor environment only have 3.39%. The experiments proved that approach can achieve real time autonomous landing system for indoor and outdoor environment. However, the cooperation operation performance only achieve in indoor environment, performance need improved.
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Lai, Hsin-Chou, e 賴信州. "The Multi-target Searching Of Multiple Mobile Robots". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/7jkdq2.
Testo completoAbstract (sommario):
碩士吳鳳科技大學
光機電暨材料研究所
100
The thesis studies target searching on the unknown environment using single or multiple mobile robots in the programs motion path from start position to target position. The Dynamic Programming Algorithm was applied in target searching to solve the problem of the minimum displacement. Each robot is with cylinder shape; its diameter, height and weight are 10cm, 15cm and 1.5kg, respectively, The controller of the mobile robot is MCS-51, and uses KEIL-C control processing language to program. The mobile robot contains a control module (contains two driver modules), a obstacle detection module, a voice module, a wireless RF communication module, an encoder module and a compass module. Mobile robots are able to correct the orientation using the compass module. The encoder module calculates movement displacement and compensates the position error. We verified experiment scenario using multiple mobile robots on the grid based platform. The supervised computer controls morote robots moving on the platform according to the programmed motion path. In the experimental results, mobile robots can receive the command from the supervised computer via wireless RF interface, and move to the unknown target position, and find the optimal motion path on the many times test according to the proposed algorithm. They also are capable to search fire source in the building, and plan escaping path leaving the fire source.
38
(5930144), Scott M. Peterson. "Target Types and Placement for Terrestrial and Mobile Mapping". Thesis, 2019.
Cerca il testo completoAbstract (sommario):
The use of digital three-dimensional (3D) data has increased over the last two decades as private and public firms have begun to realize its utility. Mobile Terrestrial Laser Scanning (MTLS) or Mobile Mapping Systems (MMS), which utilizes LiDAR (Light Detection and Ranging) data collection from a moving platform along with advances in positioning systems—e.g., Global Navigation Satellite Systems (GNSS), Inertial Navigation Systems (INS), and Distance Measurement Instruments (DMIs)—have paved the way for efficient, abundant, and accurate 3D data collection. Validation and control targets are vital to ensure relative and/or absolute accuracy for MTLS projects. The focus of this dissertation is to evaluate several types of targets and the positional spacing of said targets for MTLS.A mostly planar two-dimensional (2D) targeting system (painted target on ground) is commonly used to constrain, register, and validate the 3D point clouds from MTLS. In this dissertation, 3D objects—a sphere and a cube—were evaluated with varied angles of incidence and point densities as more appropriate alternatives to constrain and validate the 3D MTLS point clouds. Next, a planar circular 2D target—with the use of the raw intensity of the LiDAR pulse as another measured dimension—was evaluated as a proof of concept to also constrain and validate 3D LiDAR data. A third and final component of this dissertation explored analyses of INS data to determine the positional spacing of control and validation targets in MTLS projects to provide maximum accuracy for all data points.
39
Yen, Yuan-tzu, e 嚴苑慈. "Patrolling Path Planning for Target Detection with Mobile Sensors". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/gx2s75.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
資訊工程系
99
Wireless sensor networks have been used for a variety of purposes such as wildlife habitats monitoring, malicious enemy detection, and climate observation. Conventionally, stationary sensors are used to carry out sensing tasks. However, stationary sensors could lead to many problems such as communication overhead and coverage holes. This thesis investigates the problem of detecting a target or event using mobile sensors in a region with or without obstacles. The goal is to maximize the worst-case detection probability over the monitored region and reduce patrolling length of mobile sensors. An approach, namely critical sensing location path planning (CSLP), is developed to guide mobile sensors in order to collect data in an efficient way. CSLP directs mobile sensors to take measurements at carefully selected locations and reduces the patrolling path by solving a Travelling Salesman Problem. The proposed method can be used for cases either in the presence or absence of obstacles. Moreover, the thesis considers load balance problem if multiple mobile sensors are used. A method based on K-means clustering algorithm is developed to balance patrolling load for each sensor. The performance of CSLP is shown by simulations for regions with and without obstacles. The results show that CSLP is an effective solution for the proposed mobile sensing architecture in terms of detection probability and patrolling path length of mobile sensors. In addition, the performance of the K-means clustering based balance algorithm is compared to one based on a minMax clustering algorithm. Simulation results show that the former outperforms the later in balancing patrolling length for each sensor.
40
Syu, Siou-Ci, e 許修齊. "Trap Coverage and Target Tracking in Mobile Sensor Networks". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/18262636348302071764.
Testo completoAbstract (sommario):
碩士國立臺南大學
資訊工程學系碩士班
102
In the thesis, we focus on discussing how to build wireless sensor network by usage of mobile sensors, and how to provide the characteristic of trap coverage which performs a sufficient coverage model for users in many applications in mobile sensor network. The purpose of target tracking with the characteristic of trap coverage can be reached based on trap adjustment and the mobility of mobile sensors. The advantage of building wireless sensor networks by usage of mobile sensors is mainly that the network topology is able to be reconfigured and obtain a better performance level due to its mobility. Because of the trap under trap coverage, target will be presumably undetected. It causes a serious error or fail for target tracking. However, this characteristic of trap coverage is contrary to mobile target detection and tracking. In the thesis, the advantages of trap coverage can be retained and the performance in target tracking and detection can be improved. Experimental results show the proposed method can be efficiently reduced target missing time through the mobile sensor movements in mobile sensor networks based on our simulation and analysis.
41
Simões, Miguel Bruno Loureiro. "Is T-mobile U.S. a good target for Comcast". Master's thesis, 2016. http://hdl.handle.net/10400.14/20226.
Testo completoAbstract (sommario):
Throughout 2015 there was a rumor in the market that the U.S.-based cable company,
Comcast, could be expanding its segments to wireless. Despite offering cable TV, broadband
and voice or even by operating theme parks, the company may be after T-Mobile U.S., a
Deutsche Telekom subsidiary. Despite its failed attempt to buy Time-Warner Cable, it is
expected that such a deal would occur for Comcast in a near future. Therefore, following the
company strategic objectives, this thesis stresses the effects of acquiring T-Mobile U.S. in both,
financial and strategic terms. With total synergies expected to achieve $5,130M and a total
premium of $4,429M, such a deal would bring Comcast a net benefit of $5,632M. With a final
price offer of $41.61 per share, the deal is recommended and should occur as soon as possible
for the sake of the companies in the process.Ao longo de 2015 houve rumores no mercado de que a Comcast - empresa de cabo que opera nos Estados Unidos, poderia expandir a sua atividade em direção à indústria de telecomunicações móveis. Mesmo tendo segmentos como televisão por cabo, internet e voz, ou até mesmo parques de diversão temáticos, é possível que a empresa esteja inclinada a comprar a T-Mobile U.S., subsidiária americana da Deutsche Telekom. Depois de falhada a tentativa de compra da Time Warner Cable, é possível que a Comcast continue a procurar novos negócios dentro do mesmo segmento num futuro próximo. Assim, e de acordo com os objetivos estratégicos da empresa, esta tese pretende identificar quais as consequências de tal aquisição, em termos financeiros e estratégicos. Com sinergias totais estimadas em $5,130M e um prémio de $4,429M, a Comcast teria um benefício líquido de $5,632M. Com um preço final de $41.61 por ação, e tendo em conta os objetivos das duas empresas, o negócio é recomendando e deve até ocorrer nos próximos tempos para beneficio das partes envolvidas.
42
Chen, Wen Cheng, e 陳文正. "Mobile Sensors for Target Tracking via Modified Particle Filter". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/75526855703780405712.
Testo completoAbstract (sommario):
碩士國立高雄應用科技大學
電機工程系
97
We propose an estimation algorithm for location tracking and dynamic motion model of mobile units in sensor network. Estimate the trajectories of moving targets by collecting the information from sensors measurements, and assume that sensors can be randomly moving within a limited radius r at every time step. The sensor nearest to the target is chosen to supply the distance measurements. Our proposed tracking algorithm is based on modified particle filter (MPF). MPF means PF with varying particle numbers. For a nominal PF algorithm, particle number is fixed and we defined the nominal one to be the so called fixed particle filter (FPF). Estimation of mobility states, which consist of position, velocity, and acceleration of the target, are accomplished through the processing of modified particle filter using the measurements through the radar sensors. The simulation results show what we proposed, mobility tracking and the associated algorithms, have excellent convergence properties, stability, and less computationally demanding that can be applied in a variety of sensor network applications.
43
Lu, Wang-Chuan, e 呂旺全. "Monocular Vision-based Target Localization for Mobile Vehicle Tasks". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/43734967459036160787.
Testo completoAbstract (sommario):
碩士國立交通大學
電機學院電機與控制學程
99
In this paper, MVTL algorithm presents a vision-based technology for localizing targets in 3D environment which have to be detected by a mobile vehicle. MVTL is abbreviated from Monocular Vision-based Target Localization. This is achieved by the combination of different types of sensors including optical wheel encoders, an electrical compass and visual observations with a single camera. Based on the motion model and image sequences, we employ an extended Kalman filter (EKF) to estimate target locations. The proposed localization system is applicable in practice because it is not necessary to have the initializing setting regarding starting the system from artificial landmarks of known size. The technique is especially suitable for navigation and target tracing for an indoor robot and has a high potential extension to surveillance and monitoring for UAVs (Unmanned Aerial Vehicles) with aerial odometry sensors. The experimental results present “cm” level accuracy of the localizations of the targets in indoor environment under a high speed vehicle movement.
44
Wang, Pi-shih, e 王丕獅. "Energy-Efficient Wireless Sensor Networks for Mobile Target Detections". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/39781232932984651417.
Testo completoAbstract (sommario):
碩士國立中央大學
資訊工程研究所
100
In battlefields, the wireless sensor network can be used for target detection and data collection. However, the mobility of targets as well as the sinks creates challenges for the design and implementation of the system. While there are research proposals capable of handling multiple mobile sinks, these protocols either assume the knowledge of sink location or create too many flooding, leading to a quicker energy consumption. To deal with this issue, we propose a framework for data collection in wireless sensor networks, namly Dynamic and Adaptive Grid (DAG). In our framework, we take the advantages of both grid and tree data structures to route queries and data efficiently. In addition, two mechanisms are introduced to balance the load in the network. The first one helps to distribute the tasks more evenly; and the second one adjust the size of grids to balance the traffic load in each grid. Last, an improved query aggregation is proposed to reduce the query response time and the traffic associated with each query. The simulation results show that DAG outperforms the best known data collection solutions for wireless sensor networks with multiple mobile targets and sinks.
45
Wen, Yung-Jen, e 溫詠仁. "Target Finding and Following on a Wheeled Mobile Robot". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/91030689789945210402.
Testo completoAbstract (sommario):
碩士國立臺灣大學
機械工程學研究所
99
This paper focuses on development of wheel robot intelligent capabilities, according to different signals of different sensors to achieve the target following and outdoor static robot recall. In the target following, low-cost sensors and a low-computation algorithm are utilized to realize the target following and obstacles avoidance. In order to locate target, the sensing system is established to detect the target direction based on infrared remote receivers experiment, and the infrared range finders are used to detect the target distance. The robot can track and follow the target at various speeds with distance settings, and by using ultrasonic sensors to avoid obstacles, is capable of moving in human environment. In addition, the odometr mode allows the robot to track the target’s last position when the signals are obstructed. Target following experimental validation of human following and robot following are executed to evaluate the performance of the proposed system setup. In the robot recall, the received signal strength indication (RSSI) and the search algorithm are used to calculate the robot to the target position. Finally, according to experiment results under different distances, we plan the step for the realization of outdoor static mode robot recall.
46
Cheng, Shih-Wei, e 鄭世偉. "A Probability Model for Dynamic Target Location Prediction and Multi-Target Tracking in Mobile Sensor Network". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/pp4be4.
Testo completoAbstract (sommario):
碩士國立東華大學
資訊工程學系
102
Sensor networks can be static or dynamic. Dynamic sensor networks are emerging in recent years with the development of mobile devices. In this thesis, we continue the line of work in our lab on cooperative techniques for multi-target tracking in mobile sensor networks based on refined target prediction model and coverage evaluation method. Prior works within our lab are all based on heuristic tracking strategies without accurate prediction of target path. We proposed a probabilistic model for dynamic target location prediction and sensor coverage evaluation. We also proposed two tracking strategies, namely Performance Tracking and Smart Tracking with the goals of optimizing coverage rate or energy consumption. We compared our new strategies with traditional heuristic strategies in the simulation environment. Evaluation results demonstrate that Performance Tracking is better than the traditional tracking by 24%~33% in tracking success rate. Smart Tracking is better than traditional tracking in energy cost by 29%~40%.
47
Du, Pei-Hua, e 杜佩樺. "Cooperative tracking for Multi-Target Tracking in Mobile Sensor Networks". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/umktg2.
Testo completoAbstract (sommario):
碩士國立東華大學
資訊工程學系
100
Recently, Wireless sensor networks are a new technology can be used for military or medical, wireless sensor networks need to be monitored for the user area, the deployment of a large number of sensing and communications node (Sensor Node), the network system formed by these nodes can be referred to as wireless sensor networks. The sensor network can be divided into static sensor network and dynamic sensor network is composed by the static sensors, however, the rapid development of mobile phone technology, mobile device technology continues to change with technology, so the paper is dynamic sensing device consisting of wireless sensor networks using mobile sensors to improve the efficiency of target tracking and binding on the transmission of information integration. This study to Collaborative Shifting, Tracking and Information Aggregation for Multi-Target Tracking in Mobile Sensor Networks[21], to continue to do in-depth discussion. Tracking method proposed in this strategy, we found that the tracking method is incomplete, we want to enhance the tracking rate, it was able to fast track to the target, so for this problem, the experiments focused to enhance the tracking efficiency considerations. Cooperate Track is style tracking to achieve higher tracking efficiency, we also use a three track strategy : One stationary and One Move, Tail Following and Predictive Approaching, Parallel movement.
48
Masoudimansour, Walid. "Energy-Efficient Algorithms for Target Monitoring in Mobile Sensor Networks". Thesis, 2012. http://spectrum.library.concordia.ca/974650/6/masoudimansour_MASc_F2012.pdf.
Testo completoAbstract (sommario):
The main focus of this work is directed towards maximization of the lifetime of a network of cooperating mobile sensors monitoring a pre-specified target. It is assumed that the main sources of energy consumption in the network are movement, communication and sensing. It is desired to gather information about a moving target in a 2D field and find a proper route to transmit it to a fixed base or destination point. In order to find the most efficient route for transmitting information, the field is discretized as a grid of nodes. It is assumed that the sensors and target are located in the nodes at any point in time. A direct graph is subsequently constructed whose vertices are the grid nodes, and whose edges are weighted properly based on their residual energy. The proper set of nodes are then obtained (which form the desired route for maximizing the lifetime of the network) by solving the shortest path problem in the resultant graph. Finally, a proper model is adopted for the batteries to plan the sensor movement by solving a nonlinear programming problem to minimize the energy consumption of the overall network.
49
Lin, Jing-Wei, e 林靖維. "Target area detection in flat environmentby using mobile sensor network". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/29696559851309213353.
Testo completoAbstract (sommario):
碩士國立中央大學
資訊管理研究所
96
The application issue of wireless sensor network in various areas had been widely discussed. With the development of concepts and technologies of mobile sensor, the issues of mobile sensor network are also arising. The mobility feature of mobile sensors makes the sensing area of wireless sensing network can be adjusted dynamically. Hence, mobile sensor network can be used in detection operations of abnormal environments such as conflagration or oil spill areas. Traditional wireless sensor networks detect environment by the way of random deployment. Due to the higher cost of mobile sensors, it is inappropriate to use mobile sensors by the same way. The aim of this study is to design an application model for small mobile sensor network to discover unknown target areas in the environment. To detect the targets efficiently, the mobile sensors should be formatted to a network and operate as a group based on a systematic sensing mechanism. With this concept, this study is composed with two parts － mobile sensor network structure and sensing mechanism. In the part of mobile sensor network structure, we firstly propose a basic network model called SensorGroup. To reduce the requirement for the localization ability of mobile sensor and also the construction cost of network, an advanced structure called Centrlized SensorGroup is proposed by combining a wireless localization mechanism with SensorGroup. In the part of sensing mechanism, we firstly propose S-shaped sensing mechanism. In this basic mechanism SensorGroup senses the target area with a regular S-shaped movement. To improve the efficiency of sensing operation, we then propose an incremental clustering aided sensing mechanism. In this advanced mechanism, SensorGroup can adjust its movement dynamically based on the cluster analysis of sensing record of target area to achieve higher sensing efficiency.
50
(8660301), Chiyu Zhang. "MULTI-TARGET TRACKING AND IDENTITY MANAGEMENT USING MULTIPLE MOBILE SENSORS". Thesis, 2020.
Cerca il testo completoAbstract (sommario):
Due to their rapid technological advancement, mobile sensors such as unmanned aerial vehicles (UAVs) are seeing growing application in the area of multi-target tracking and identity management (MTIM). For efficient and sustainable performance of a MTIM system with mobile sensors, proper algorithms are needed to both effectively estimate the states/identities of targets from sensing data and optimally guide the mobile sensors based on the target estimates. One major challenge in MTIM is that a target may be temporarily lost due to line-of-sight breaks or corrupted sensing data in cluttered environments. It is desired that these targets are kept tracking and identification, especially when they reappear after the temporary loss of detection. Another challenging task in MTIM is to correctly track and identify targets during track coalescence, where multiple targets get close to each other and could be hardly distinguishable. In addition, while the number of targets in the sensors’ surveillance region is usually unknown and time-varying in practice, many existing MTIM algorithms assume their number of targets to be known and constant, thus those algorithms could not be directly applied to real scenarios.
In this research, a set of solutions is developed to address three particular issues in MTIM that involves the above challenges: 1) using a single mobile sensor with a limited sensing range to track multiple targets, where the targets may occasionally lose detection; 2) using a network of mobile sensors to actively seek and identify targets to improve the accuracy of multi-target identity management; and 3) tracking and managing the identities of an unknown and time-varying number of targets in clutter.