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Cooperative Context-Aware Setup and Performance of Surveillance Missions Using Static and Mobile Wireless Sensor NetworksPignaton de Freitas, Edison January 2011 (has links)
Surveillance systems are usually employed to monitor wide areas in which their usersaim to detect and/or observe events or phenomena of their interest. The use ofwireless sensor networks in such systems is of particular interest as these networks can provide a relative low cost and robust solution to cover large areas. Emerging applications in this context are proposing the use of wireless sensor networks composed of both static and mobile sensor nodes. Motivation for this trend is toreduce deployment and operating costs, besides providing enhanced functionalities.The usage of both static and mobile sensor nodes can reduce the overall systemcosts, by making low-cost simple static sensors cooperate with more expensive andpowerful mobile ones. Mobile wireless sensor networks are also desired in somespecific scenarios in which mobility of sensor nodes is required, or there is a specificrestriction to the usage of static sensors, such as secrecy. Despite the motivation,systems that use different combinations of static and mobile sensor nodes are appearing and with them, challenges in their interoperation. This is specially the case for surveillance systems.This work focuses on the proposal of solutions for wireless sensor networks including static and mobile sensor nodes specifically regarding cooperative andcontext aware mission setup and performance. Orthogonally to the setup and performance problems and related cooperative and context aware solutions, the goalof this work is to keep the communication costs as low as possible in the executionof the proposed solutions. This concern comes from the fact that communication increases energy consumption, which is a particular issue for energy constrained sensor nodes often used in wireless sensor networks, especially if battery supplied. Inthe case of the mobile nodes, this energy constraint may not be valid, since their motion might need much more energy. For this type of node the problem incommunicating is related to the links’ instabilities and short time windows availableto receive and transmit data. Therefore, it is better to communicate as little as possible. For the interaction among static and mobile sensor nodes, all thesecommunication constraints have to be considered.For the interaction among static sensor nodes, the problems of dissemination and allocation of sensing missions are studied and a solution that explores local information is proposed and evaluated. This solution uses mobile software agentsthat have capabilities to take autonomous decisions about the mission dissemination and allocation using local context information so that the mission’s requirementscan be fulfilled. For mobile wireless sensor networks, the problem studied is how to perform the handover of missions among the nodes according to their movements.This problem assumes that each mission has to be done in a given area of interest. In addition, the nodes are assumed to move according to different movement patterns,passing through these areas. It is also assumed that they have no commitment in staying or moving to a specific area due to the mission that they are carrying. To handle this problem, a mobile agent approach is proposed in which the agents implement the sensing missions’ migration from node to node using geographical context information to decide about their migrations. For the networks combining static and mobile sensor nodes, the cooperation among them is approached by abiologically-inspired mechanism to deliver data from the static to the mobile nodes.The mechanism explores an analogy based on the behaviour of ants building and following trails to provide data delivery, inspired by the ant colony algorithm. It is used to request the displacement of mobile sensors to a given location according tothe need of more sophisticated sensing equipment/devices that they can provide, so that a mission can be accomplished.The proposed solutions are flexible, being able to be applied to different application domains, and less complex than many existing approaches. The simplicity of the solutions neither demands great computational efforts nor large amounts of memory space for data storage. Obtained experimental results provide evidence of the scalability of these proposed solutions, for example by evaluatingtheir cost in terms of communication, among other metrics of interest for eachsolution. These results are compared to those achieved by reference solutions (optimum and flooding-based), providing indications of the proposed solutions’ efficiency. These results are considered close to the optimum one and significantly better than the ones achieved by flooding-based solutions.
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Direction of Arrival Estimation Improvement for Closely Spaced Electrically Small Antenna ArrayYu, Xiaoju 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / In this paper, a new technique utilizing a scatterer of high dielectric constant in between electrically small antennas to achieve good Direction of arrival (DOA) estimation performance is demonstrated. The phase information of the received signal at the antennas is utilized for direction estimation. The impact of the property of the scatterer on the directional sensitivity and the output signal to noise ratio (SNR) level are studied. Finally the DOA estimation accuracy is analyzed with the proposed technique under the consumption of white Gaussian noise environment.
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Advances in Non-Foster Circuit Augmented, Broad Bandwidth, Metamaterial-Inspired, Electrically Small AntennasZhu, Ning 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / There are always some intrinsic tradeoffs among the performance characteristics: radiation efficiency, directivity, and bandwidth, of electrically small antennas (ESAs). A non-Foster enhanced, broad bandwidth, metamaterial-inspired, electrically small, Egyptian axe dipole (EAD) antenna has been successfully designed and measured to overcome two of these restrictions. By incorporating a non-Foster circuit internally in the near-field resonant parasitic (NFRP) element, the bandwidth of the resulting electrically small antenna was enhanced significantly. The measured results show that the 10 dB bandwidth (BW10dB) of the non-Foster circuit-augmented EAD antenna is more than 6 times the original BW10dB value of the corresponding passive EAD antenna.
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Face Identification in the Internet EraStone, Zachary January 2012 (has links)
Despite decades of effort in academia and industry, it is not yet possible to build machines that can replicate many seemingly-basic human perceptual abilities. This work focuses on the problem of face identification that most of us effortlessly solve daily. Substantial progress has been made towards the goal of automatically identifying faces under tightly controlled conditions; however, in the domain of unconstrained face images, many challenges remain. We observe that the recent combination of widespread digital photography, inexpensive digital storage and bandwidth, and online social networks has led to the sudden creation of repositories of billions of shared photographs and opened up an important new domain for unconstrained face identification research. Drawing upon the newly-popular phenomenon of “tagging,” we construct some of the first face identification datasets that are intended to model the digital social spheres of online social network members, and we examine various qualitative and quantitative properties of these image sets. The identification datasets we present here include up to 100 individuals, making them comparable to the average size of members’ networks of “friends” on a popular online social network, and each individual is represented by up to 100 face samples that feature significant real-world variation in appearance, expression, and pose. We demonstrate that biologically-inspired visual representations can achieve state-of-the-art face identification performance on our novel frontal and multi-pose face datasets. We also show that the addition of a tree-structured classifier and training set augmentation can enhance accuracy in the multi-pose setting. Finally, we illustrate that the machine-readable “social context” in which shared photos are often embedded can be applied to further boost face identification accuracy. Taken together, our results suggest that accurate automated face identification in vast online shared photo collections is now feasible. / Engineering and Applied Sciences
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Toward machines with brain inspired intelligence: A study on Hierarchical Temporal Memory TechnologyHeravi Khajavi, Roxanne January 2008 (has links)
This Master Thesis has been performed at the Department of Electrical Engineering, Division of Electronic Devices in Linköping University. A study about HTM technology and a technical evaluation of advanced HTM picture recognition has been attained. HTM, which stands for Hierarchical Temporal Memory, is a technology developed by Numenta Inc. based on Jeff Hawkins theory on the brain function. The report includes also some essential facts about the brain for guidelines of engineers to reach a better understanding of the connection between the brain and the technology of HTM. Even if the technique of HTM is still young but the ambition of its developer is to design truly intelligent machines.
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Bio-inspired cooperative exploration of noisy scalar fieldsWu, Wencen 16 September 2013 (has links)
A fundamental problem in mobile robotics is the exploration of unknown fields that might be inaccessible or hostile to humans. Exploration missions of great importance include geological survey, disaster prediction and recovery, and search and rescue. For missions in relatively large regions, mobile sensor networks (MSN) are ideal candidates. The basic idea of MSN is that mobile robots form a sensor network that collects information, meanwhile, the behaviors of the mobile robots adapt to changes in the environment. To design feasible motion patterns and control of MSN, we draw inspiration from biology, where animal groups demonstrate amazingly complex but adaptive collective behaviors to changing environments.
The main contributions of this thesis include platform independent mathematical models for the coupled motion-sensing dynamics of MSN and biologically-inspired provably convergent cooperative control and filtering algorithms for MSN exploring unknown scalar fields in both 2D and 3D spaces. We introduce a novel model of behaviors of mobile agents that leads to fundamental theoretical results for evaluating the feasibility and difficulty of exploring a field using MSN. Under this framework, we propose and implement source seeking algorithms using MSN inspired by behaviors of fish schools. To balance the cost and performance in exploration tasks, a switching strategy, which allows the mobile sensing agents to switch between individual and cooperative exploration, is developed. Compared to fixed strategies, the switching strategy brings in more flexibility in engineering design. To reveal the geometry of 3D spaces, we propose a control and sensing co-design for MSN to detect and track a line of curvature on a desired level surface.
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Drabužių kolekcija G. Klimto kūrybos motyvais "Moteris - Sirena" / Clothes collection based on G. Klimt art motifs "Women - Siren"Monkūnaitė, Eglė 29 June 2012 (has links)
Bakalauro darbas „Moteris – Sirena“ atspindi, kaip galima remiantis Gustavo Klimto tapybos darbais sukurti kolekciją. Darbe nagrinėjama G. Klimto kūryba, aiškinamasi, kaip jo tapybos darbai atsispindi įvairiose drabuţių kolekcijose. Bakalauro darbą sudaro dvi dalys: teorinis aprašas ir moteriškų drabuţių kolekcija G. Klimto kūrybos motyvais.Aptariama, kokios įtakos menas turi aprangos dizaineriams, apţvelgiama, kaip tapybos darbai tampa įkvėpimo šaltiniu,apibūdinama mitologinių sirenų samprata bei jų atspindţiai G. Klimto kūryboje,analizuojamas fatališkos moters įvaizdis istorijoje bei šiuolaikiniame gyvenime. Pateikiamos dizainerių kolekcijos, formuojančios fatališkos moters įvaizdį,pristatomos įvairių dizainerių drabuţių kolekcijos, remiantis G. Klimto kūrybos motyvais,pagrindţiama idėja, pateikiami eskizai, projektai, technologiniai mėginiai, aprašomas drabuţių kolekcijos kūrimo procesas – konstravimas, modeliavimas, siuvimas. Taip pat pateikiamos įvykdytų drabuţių modelių fotografijos ir numatomas kolekcijos pristatymas. / This bachelor work "Women - Siren" show how can based Gustav Klimt paintings create a collection in which a woman is like a work of art. Analyzed by G. Klimt works, examines how the paintings are reflected in different clothing collections.Reviews the concept of mythological sirens and their reflections in G. Klimt works,analyzes the image of the femme fatale in the history and today life. Designers' collections are presented based on a femme fatale image.The various collections of clothing based on G. Klimt art motifs are presents.There is also analysis of peculiarities of form, texture, symbols and colors in order to interpret it in the clothes collection there is a well-founded idea. Sketches, projects and technological samples are presented. The process of creation of clothes ensemble (construction, modeling, sewing) is also described. There are photos of accomplished models and the presentation is foreseen.
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A system design approach to neuromorphic classifiersRamakrishnan, Shubha 09 January 2013 (has links)
This work considers alternative strategies to mainstream digital approaches to signal processing - namely analog and neuromorphic solutions, for increased computing efficiency. In the context of a speech recognizer application, we use low-power analog approaches for the signal conditioning and basic auditory feature extraction, while using a neuromorphic IC for building a dendritic classifier that can be used as a low-power word spotter. In doing so, this work also aspires to posit the significance of dendrites in neural computation.
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Towards Fault Reactiveness in Wireless Sensor Networks with Mobile Carrier RobotsFalcon Martinez, Rafael Jesus 04 April 2012 (has links)
Wireless sensor networks (WSN) increasingly permeate modern societies nowadays. But in spite of their plethora of successful applications, WSN are often unable to surmount many operational challenges that unexpectedly arise during their lifetime. Fortunately, robotic agents can now assist a WSN in various ways. This thesis illustrates how mobile robots which are able to carry a limited number of sensors can help the network react to sensor faults, either during or after its deployment in the monitoring region.
Two scenarios are envisioned. In the first one, carrier robots surround a point of interest
with multiple sensor layers (focused coverage formation). We put forward the first known algorithm
of its kind in literature. It is energy-efficient, fault-reactive and aware of the bounded
robot cargo capacity. The second one is that of replacing damaged sensing units with spare,
functional ones (coverage repair), which gives rise to the formulation of two novel combinatorial
optimization problems. Three nature-inspired metaheuristic approaches that run at a centralized location are proposed. They are able to find good-quality solutions in a short time. Two frameworks for the identification of the damaged nodes are considered. The first one leans upon diagnosable systems, i.e. existing distributed detection models in which individual units perform tests upon each other. Two swarm intelligence algorithms are designed to quickly and reliably spot faulty sensors in this context. The second one is an evolving risk management framework for WSNs that is entirely formulated in this thesis.
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Force and impulse control for spring-mass runningKoepl, Devin N. 02 December 2011 (has links)
We present a novel control strategy for running which is robust to disturbances, and makes excellent use of passive dynamics for energy economy. The motivation for our control strategy is based on observations of animals, which are able to economically walk and run over varying terrain and ground dynamics. It is well-known that steady-state animal running can be approximated by spring-mass models, but these passive dynamic models describe only steady-state running and are sensitive to disturbances that animals can accommodate. While animals rely on their passive dynamics for energy economy, they also incorporate active control for disturbance rejection. The same approach can be used for spring-mass walking and running, but an active controller is needed that interferes minimally with the passive dynamics of the system. We demonstrate, in simulation, how force control combined with a leg spring stiffness tuned for the desired hopping frequency provides robustness to disturbances on a model for robot hopping, while maintaining the energy economy of a completely passive system during steady-state operation. Our strategy is promising for robotics applications, because there is a clear distinction between the passive dynamic behavior of the model and the active controller, it does not require sensing of the environment, and it is based on a sound theoretical background that is compatible with existing high-level controllers for ideal spring-mass models. / Graduation date: 2012
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