White-nose syndrome (WNS), caused by the introduced fungal pathogen, Pseudogymnoascus destructans, has caused precipitous declines in bat populations including the now endangered northern long-eared bat (Myotis septentrionalis; NLEB). Remnant populations of NLEB have been found outside their traditional range in areas of the urbanized Piedmont and also the Coastal Plain of the mid-Atlantic region of the United States, where little is known about their summertime day-roost habitat needs. More broadly for the species, little research has examined the day-roost habitat use of both male and females. This information is vital to inform management and policy for the conservation of this endangered species. In this dissertation, I captured NLEB at three properties in eastern Virginia and Washington D.C. Captures at Marine Corps Base Quantico (MCBQ) and Prince William Forest Park (PRWI) in Virginia were male-biased and Rock Creek Park (ROCR) captures in D.C. were female-biased. I found that overall NLEB are associated with mature, deciduous forest. Males used red maples (Acer rubrum) in later decay stages and lower crown classes at MCBQ/PRWI. Females used taller oaks (Quercus) at ROCR. Differences between the two study areas may be an artifact of MCBQ/PRWI being an early mature forest whereas much of ROCR is approaching late mature to old-growth gap-phase conditions. Building off the fact that many WNS affected bat species are now substantially more difficult to detect on the landscape, I explored novel methods to help increase detection of bats during acoustic surveys. This included developing and testing an experimental ultraviolet (UV) light lure that attracted insects and thereby attracted bats. The lure increased overall bat feeding buzz calls and had a species-specific response, primarily attracting eastern red bats (Lasiurus borealis). The lure elicited an interesting negative response from NLEB within the illuminated area, but an increase above control conditions beyond the illuminated area. Overall, the UV lure shows promise for increasing detection of bats and warrants further research, however caution should be exercised as some bats showed a negative response. I also investigated the effects of environmental clutter on the reception of ultrasonic bat echolocation signals to help researchers better understand how different clutter types and configurations affect and potentially bias acoustic survey results. This is especially important when surveying for clutter-adapted bats, such as NLEB which are traditionally biased against in acoustic surveys due to their habitat associations and low detection probability. I found that the recording angle of the bat in relation to the microphone overshadowed most other effects. On-axis recording created the best quality recording and the signal rapidly degraded as the angle increased. Therefore, placement of microphones to where bats are expected to be flying is critical. Many small clutter objects, analogous to a young forest with a high stocking rate substantially degraded echolocation signals. Fewer, large objects, analogous to a mature forest with large trees and little understory actually generated echoes that were identifiable to species that would be beneficial to improving detection probability and occupancy estimates, but might generate bias by overcalculating activity estimates. / Doctor of Philosophy / A disease called white-nose syndrome (WNS), caused by the fungal pathogen, Pseudogymnoascus destructans, was introduced into the U.S. around 2006 and has decimated bat populations across much of the U.S. and Canada. Bats are responsible for providing important pest insect control services to the agriculture and forestry industries as well as helping to control disease carrying insects. Once particular species, the northern long-eared bat (Myotis septentrionalis; NLEB) has seen some of the heaviest declines. Once a common bat in forests across the eastern and mid-western portions of North America, the NLEB is now considered an endangered species. Recently, populations of this bat have been found in areas where they were previously not known to exist and they represent potentially important remnant populations with high conservation value. In order to protect these NLEB, scientists must understand their forest habitat needs for roosting during the day and rearing young. Most past studies have focused on female NLEB, so information on male roost use is also needed. I captured NLEB at Marine Corps Base Quantico (MCBQ) and Prince William Forest Park (PRWI) in Virginia as well as at Rock Creek Park (ROCR) in Washington, D.C. and tracked NLEB to their day-roosts to characterize their habitat needs at multiple scales ranging from the day-roost itself, the surrounding forest area, and the greater landscape around the bat roosting areas. I found that NLEB prefer to roost in older deciduous hardwood forests. Male NLEB used red maples (Acer rubrum) that were shorter and more decayed than surrounding trees at MCBQ/PRWI. Females used taller oak trees (Quercus) at ROCR. Differences observed in the analysis between the two study areas may be an artifact of MCBQ/PRWI being a younger forest whereas much of ROCR is approaching conditions of a very old forest. Building off the fact that many WNS affected bat species are now substantially more difficult to find out on the landscape, I explored new research methods to help increase detection of bats during acoustic surveys. Scientists often use acoustic recording devices to record ultrasonic (above human hearing) echolocation calls that bats use for navigation and hunting at night. Those calls can be identified as specific types of bats for use in environmental studies using automated computer programs. The problem however, is that bats must fly close to the microphone in order to record a clear sound file that can be identified by the software. I built and tested a device that uses ultraviolet (UV) "blacklights" to attract insects that bats eat and thereby attract bats to an array of recording devices. The lure device worked, but for individual species of bats rather than all bats. Of particular interest is that NLEB were repelled within the area illuminated by the UV light lure, but increased outside the illuminated area. Overall, a UV light lure shows promise for increasing detection of bats, but caution is recommended because some bats seemed to avoid the light. I also investigated how clutter around these recording devices, such as trees and branches, affects the quality of recorded sound files under controlled conditions. I found that the angle of the recording device microphone to the sound source (a bat) mattered the most. Many smaller objects between a bat and the microphone, such as many small trees in a young forest, resulted in the worse recordings. Fewer large objects, such as large, old trees, resulted in echoes of the bat calls being recorded and actually helped the software identify the calls to a specific type of bat. However, this also warrants caution, as those echoes could introduce bias into counts of nightly bat activity.

Cette thèse, réalisée en partenariat avec Rockwell-Collins France, s'inscrit dans le cadre du développement d'un radar FMCW aéroporté de détection d'obstacles fonctionnant en bande X. Dans cette thèse, nous nous plaçons dans le contexte plus général de détection de cibles présentant un risque de collision avec le porteur radar dans du fouillis de sol. Les performances de détection des cibles d'intérêt diminuent grandement lorsqu'elles se retrouvent dans les zones de fouillis. Le principal objectif de cette thèse réside ainsi dans la conception de traitements en vue d'améliorer les capacités de détection et de reconnaissance de cibles présentant un risque de collision avec le porteur radar dans les zones de fouillis de sol. Dans un premier temps, nous effectuons une revue des traitements adaptés à la détection d'obstacles par un radar aéroporté FMCW: formation de faisceaux conventionnelle, compensation de migration distance, et création d'une cartographie distance-vitesse par double FFT. Dans un second temps, nous utilisons ensuite un traitement d'antennes adaptatif pour séparer en élévation le fouillis de sol et d'éventuels obstacles situés au-dessus du sol pouvant présenter un risque pour le porteur (câbles, pylônes, immeubles, ...). Dans la seconde partie de cette thèse, nous incluons une information supplémentaire sur le signal temporel d'une case distance avec un temps d'intégration plus long~: la variation de fréquence Doppler des cibles. Une cible de collision ou un câble ne changent pas de fréquence tandis qu'un élément au sol aura une variation connue dépendant de la vitesse du porteur et de son angle de vue. Cette information nous a tout d'abord permis de séparer le signal d'un pylône et d'un câble, pour ensuite séparer la cible de collision du fouillis de sol. Enfin, nous effectuons la détection adaptative d'une cible mobile de collision étendue en distance et noyée dans le fouillis de sol. Les algorithmes développés dans cette thèse ont été testés avec succès sur données expérimentales. / This thesis, in collaboration with Rockwell-Collins France, forms part of the development of an X-band FMCW airborne radar designed for obstacles detection and collision avoidance. More precisely, this thesis deals with the problem of detecting targets which exhibit a collision trajectory with the radar carrier, in presence of ground clutter. Target detection performances are highly degraded when the targets of interest fall into ground clutter. The main goal of this thesis is to develop signal processing methods to increase radar detection capacities and recognition for collision targets inside ground clutter. First, we give a brief review of signal processing methods for target detection using an airborne FMCW radar : conventional beamforming, range migration compensation, double-FFTs for Range-Doppler Map visualization. We then derive an adaptive antenna array processing to separate ground clutter and fixed hazardous obstacles above the ground (cables, pylons, buildings, ...) using their difference in elevation angle. In the second part of this thesis, we use a long integration time and include extra information on the time model of a range cell signal : Doppler frequency variation. A collision target does not exhibit Doppler frequency variation, whereas fixed obstacle or ground clutter exhibits a known variation depending on the carrier velocity and the aspect angle. We take advantage of this variation first to separate a cable from a pylon, and then separate collision target from ground clutter. We finally tackle the problem of adaptively detecting a collision mobile spread target in ground clutter region. The proposed algorithms in this thesis have been successively tested on experimental data.

Radar (RAdio Detection And Ranging) uses radio waves to detect the presence of a target and measure its position and other properties. This sensor has found many civilian and military applications due to advantages such as possible large surveillance areas and operation day and night and in all weather. The contributions of this thesis are within applied signal processing for radar in two somewhat separate research areas: 1) radar with array antennas and 2) radar with micro-Doppler measurements. Radar with array antennas: An array antenna consists of several small antennas in the same space as a single large antenna. Compared to a traditional single-antenna radar, an array antenna radar gives higher flexibility, higher capacity, several radar functions simultaneously and increased reliability, and makes new types of signal processing possible which give new functions and higher performance. The contributions on array antenna radar in this thesis are in three different problem areas. The first is High Resolution DOA (Direction Of Arrival) Estimation (HRDE) as applied to radar and using real measurement data. HRDE is useful in several applications, including radar applications, to give new functions and improve the performance. The second problem area is suppression of interference (clutter, direct path jamming and scattered jamming) which often is necessary in order to detect and localize the target. The thesis presents various results on interference signal properties, antenna geometry and subarray design, and on interference suppression methods. The third problem area is measurement techniques for which the thesis suggests two measurement designs, one for radar-like measurements and one for scattered signal measurements. Radar with micro-Doppler measurements: There is an increasing interest and need for safety, security and military surveillance at short distances. Tasks include detecting targets, such as humans, animals, cars, boats, small aircraft and consumer drones; classifying the target type and target activity; distinguishing between target individuals; and also predicting target intention. An approach is to employ micro-Doppler radar to perform these tasks. Micro-Doppler is created by the movement of internal parts of the target, like arms and legs of humans and animals, wheels of cars and rotors of drones. Using micro-Doppler, this thesis presents results on feature extraction for classification; on classification of targets types (humans, animals and man-made objects) and human gaits; and on information in micro-Doppler signatures for re-identification of the same human individual. It also demonstrates the ability to use different kinds of radars for micro-Doppler measurements. The main conclusion about micro-Doppler radar is that it should be possible to use for safety, security and military surveillance applications.

The effectiveness of information visualization largely depends on the ease and accuracy with which users can access the information. Visual clutter in a display can detract from a user's ability to properly read the information. An ideal visualization needs to maximize the visibility of patterns and structure and minimize the clutter present. Thus far, there has been surprisingly little work done in finding quantitative ways to measure clutter in information visualizations. The goal of this project was to create clutter measurement and reduction techniques that minimize the presence of visual clutter and maximize a user's ability to accurately read the data. These methods were tested and evaluated on a number of visualizations depicting domestic air traffic data.

Made available in DSpace on 2016-04-27T18:12:27Z (GMT). No. of bitstreams: 1 Cristiane Pequeno da Silva.pdf: 500162 bytes, checksum: 6c27082f55096bbe4e0dc0c93e84cd24 (MD5) Previous issue date: 2007-11-23 / Background: The familiar disaggregation finishes provoking a fragility in the subjective constitution, signaled in different difficulties in the child, being that one related to language one more excellent them. This dissertation had for objective to describe some difficulties in the language of three children whose histories of life present episodes of familiar disaggregation, with data of recklessness, permanence in shelter houses or substitution of family. Method: a survey next to the Conselho Tutelar de São Roque of the children whose families had been taken care of by the council members during the year of 2005. Of available handbooks, only seven had been selected, in function of the age of the children. Anamnese was carried through one and the analysis of documentations for survey of histories, the direct comment of the general behaviors of the children and the application of a test of language verbal (Tipiti) for description of the linguistic uses and deduced level of development of the language. Results: it can be observed that it has a dependence of the other in the organization of the speech of the three children, a time who already would have to establish its with certain autonomy. Conclusion: the results indicate that the fragility in the familiar structure can compromise the constitution of the subjectivity and, obviously, to modify the development of the language in the children, a time who when they are seen to the edge of the other in the speech, appear a great difficulty in elaborating its proper one / Introdução: A desagregação familiar acaba provocando uma fragilidade na constituição subjetiva, sinalizada em diferentes dificuldades na criança, sendo aquela relacionada à linguagem uma das mais relevantes. Esta dissertação teve por objetivo descrever algumas dificuldades na linguagem de três crianças cujas histórias de vida apresentam episódios de desagregação familiar, com dados de negligência, permanência em casas de abrigo ou substituição de família. Método: foi feito um levantamento junto ao Conselho Tutelar de São Roque das crianças cujas famílias foram atendidas pelas conselheiras durante o ano de 2005. Dos prontuários disponibilizados, foram selecionados apenas sete, em função da idade das crianças. Foi realizada uma anamnese e a análise de documentações para levantamento das histórias, a observação direta das condutas gerais das crianças e a aplicação de um teste de linguagem oral (Tipiti) para descrição dos usos lingüísticos e deduzido nível de desenvolvimento da linguagem. Resultados: podese observar que há uma dependência do outro na organização do discurso das três crianças, uma vez que já deveriam estabelecer o seu com certa autonomia. Conclusão: os resultados indicam que a fragilidade na estrutura familiar pode comprometer a constituição da subjetividade e, obviamente, alterar o desenvolvimento da linguagem nas crianças, uma vez que quando se vêem à margem do outro no discurso, surge uma grande dificuldade em elaborar o seu próprio

La détection radar passive met à profit des émetteurs non-coopératifs, déjà présents dans l’environnement, qui transmettent des signaux de télécommunications, de type DVB-T dans l’étude présentée.Elle utilise les réflexions de ces signaux sur de potentielles cibles et les exploite comme échos radar au niveau d’un récepteur aéroporté.Ces nouveaux systèmes de détection, par nature discrets et économes en énergie et en allocation de fréquences, étendent la surveillance à la basse altitude.Si les différentes étapes des traitements classiques utilisés en radar passif terrestre (estimation du signal de référence, réjection, filtrage adapté, détection)demandent d’être réorientées sérieusement pour répondre aux contraintes liées à la réception aéroportée,il en va de même du récepteur qui doit satisfaire les exigences matérielles de la plateforme aérienne.Dans ce but, un système expérimental embarqué sur motoplanneur a été développé permettant d’acquérir des signaux réels indispensablesà la compréhension de l’impact de la propagation des signaux DVB-T.La méthode d’estimation du signal de référence proposée permet d’une part, de lutter contre les fluctuations du canal de propagation induites par les multi-trajetsen exploitant la diversité d’antenne et d’autre part, de prendre en compte les variations temporelles en s’appuyant sur la méthode BEM (Basis Expension Model).Ensuite, une analyse théorique sur la répartition du fouillis de sol est apportée.L’exploitation des signaux expérimentaux permet de la valider par une analyse dans le plan distance-Doppler et angle-Doppler.Une projection cartésienne permet de mettre en évidence des échos forts confrontés avec la vérité terrain.L’estimation du signal de référence et la connaissance de l’étalement du fouillis de sol sont les piliers fondamentaux de la détection car ces composantes représentent deux contributions à rejeter.Pour le signal de référence, une méthode classique de réjection où les coefficients du filtre sont estimés au sens des moindres carrés est mise en oeuvre.Un filtrage spatial orthogonal à la direction d’arrivée du signal de référence est ajouté afin de diminuer l’impact du bruit émis.Le large étalement en Doppler et en distance nous a conduit à rejeter le fouillis sur des périodes de corrélation plus courtes.Les travaux présentés apportent une compréhension fine de l’impact de la propagation sur les traitements de détection en radar passif aéroporté et offrent des perspectives engageantesquant à la détection de cibles de moyennes à grandes Surfaces Equivalentes Radar. / Passive radar detection benefits from non-cooperative telecommunication broadcasters, already existing in the environment, such as DVB-T broadcasters.It uses signal reflections over potential targets. An airborne receiver takes advantage of it as radar echoes.This new kind a detection system is discrete, has low energy consumption, uses already allocated frequencies and broaden radar detection to low altitudes.Due to airborne constraints, the standard signal processing steps, as the receiving system need to be adjusted.Indeed a dedicated radar has been developped in order to get experimental signal, and therefore help deepen the understanding of propagation phenomenon.The proposed reference signal estimation allows to face channel multipath induced fluctuations on the one hand, and to take into account channel time variationsthanks to Basis Expansion Model (BEM) modeling. A theoretical analysis of the clutter spread is then drawn.Experimental results confirm the expectation in the range-Doppler and angle-Doppler domain.Besides a clutter cartesian projection highlights the major reflectors, that may be confronted to the terrain truth.Reference signal estimation and clutter spread constitute two radar detection pilars, as these components have to be cancelled.So as to reject direct path, space filtering orthogonal to the direct direction is also performed to suppress the impact of the transmitted noise.Then reference signal is cancelled via a standard rejection method based on least-square filter coefficients estimation.The large Doppler and range clutter spread, lead us to reject the reference signal over shorter correlation periods.The present work gives an accurate comprehension of propagation mechanisms impact on airborne passive radar signal processing andprovides a promising perspective regarding intermediate radar cross section target detection.

L’étude traite de la détection de cibles mobiles dans un contexte de radar passif bistatique utilisant les émetteursde télévision numérique TNT (DVB-T) comme émetteurs d’opportunité. Outre leur présence généralisée sur leterritoire, l’intérêt de ces émissions réside dans leur relative largeur de bande permettant une bonne précisiond’estimation. Le principal inconvénient de ce type d’approche réside dans l’éblouissement par le signal en trajetdirect, des échos de très faible intensité des cibles d’intérêt. Après un rappel du principe du radar bistatique etde la norme OFDM utilisée par les signaux TNT, une première étude donne une construction originale du signalde référence dans le cas multi-capteurs : le signal de référence est construit par un traitement d’antenne de typeCAPON où le balayage des paramètres optimaux est remplacé par la connaissance de signaux pilotes inséré dansles symboles OFDM. Ensuite le rapport se focalise sur l’estimation d’un filtre de canal multitrajet à partir dela connaissance de la modulation OFDM utilisée. Ce filtre, d’abord étudié comme réjecteur de fouillis originalavant détection par la fonction d’ambiguïté, donne des résultats semblables aux méthodes classiques de réjectionde fouillis standard. Étendu à toutes les fréquences Doppler, son module au carré est utilisé comme un nouveaudétecteur présentant un très faible niveau de clutter, surpassant ainsi la fonction d’ambiguïté. Une interprétationen terme de traitement d’antennes du nouveau détecteur ouvre la voie à des variantes haute-résolution de celui-ci.La validité du nouveau détecteur est illustrée par des résultats sur données réelles. / The study focuses on moving target detection from passive bistatic radar with DVB-T transmitters used asopportunity transmitters. In addition to their widespread geographical coverage, they allow a good estimationaccuracy due to their quite large bandpass. Nevertheless the continuous powerful direct path masks the verylow intensity echoes of targets of interest. The passive bistatic radar principle and the CP-OFDM standardused by DVB-T are briefly reminded, then, a new first study of reference signal retrieving in multiple sensorsconfiguration is given : the reference signal is built using a Capon receptor where the parameters scan is replacedby the knowledge of pilot signals inserted in the OFDM symbols. Next, the report addresses the multipath channelestimate by using the OFDM signal structure. This channel is firstly studied for clutter rejection before detectionfrom the cross ambiguity function (CAF). We obtain similar results than those of the classical rejection methods.This channel is extended to the whole Doppler shift, and its squared modulus acts as a new low clutter detectorthat outperforms classical CAF. A virtual beamforming interpretation of the channel estimation opens a new pathtowards high resolution array processing. Results given on real data illustrate the validity of this new channeldetector (CHAD).

Staggering the pulse repetititon intervals is a widely used solution to alleviate the blind speed problem in Moving Target Indication (MTI) radar systems. It is possible to increase the first blind speed on the order of ten folds with the use of non-uniform sampling. Improvement in blind speed results in passband fluctuations that may degregade the detection performance for particular Doppler frequencies. Therefore, it is important to design MTI filters with non-uniform interpulse periods that have minimum passband ripples with sufficient clutter attenuation along with good range and blind velocity performance. In this thesis work, the design of MTI filters with non-uniform interpulse periods is studied through the least square, convex and min-max filter design methodologies. A trade-off between the contradictory objectives of maximum clutter suppression and minimum desired signal attenuation is established by the introduction of a weight factor into the designs. The weight factor enables the adaptation of MTI filter to different operational scenarios such as the operation under low, medium or high clutter power. The performances of the studied designs are investigated by comparing the frequency response characteristics and the average signal-to-clutter suppression capabilities of the filters with respect to a number of defined performance measures.Two further approaches are considered to increase the signal-to-clutter suppression performance. First approach is based on a modified min-max filter design whereas the second one focuses on the multiple filter implementations. In addition, a detailed review and performance comparison with the non-uniform MTI filter designs from the literature are also given.

Space-Time Adaptive Processing (STAP) is an effective method in Ground Moving Target Indicator (GMTI) operation of airborne radars. Clutter suppression is the key to successful MTI operation. Airborne radars are different than the ground based ones in regard to clutter due to the displacement of the platform during operation. When STAP methods are to be investigated, one needs to have accurate signal models while evaluating performance. In this thesis, a comprehensive received signal model is developed first for an airborne antenna array. The impacts of the aircraft motion and irregularities in it, aircraft displacement during reception, intrinsic clutter motion and radar parameters have been accounted in the model and incorporated into a simulator environment. To verify the correctness of the signal simulator, the classical DPCA approach and optimum STAP methods are inspected.

We have devised a processor for pulsed Doppler radars for multi-target detection in same folded range under land and moving clutter. To this end, we have investigated the estimation of parameters, i.e., frequencies, amplitudes, and phases, of complex exponentials that model target echoes under radar clutter characterized by antenna scanning modulation with observation limited to single snapshot, i.e., one burst. The Maximum Likelihood method of estimation is presented together with the bounds on estimates, i.e., Cram&eacute / r-Rao bounds. We have analyzed linear prediction, together with its efficient implementation invented by Tufts &amp / Kumaresan, and compared its performance to other high resolution frequency estimation algorithms all modified to run under clutter. The essential part of the work is that line spectra estimation techniques model the clutter process also as a complex exponential. In addition, linear prediction combined with linear time&ndash / invariant maximum Signal to Interference Ratio (SIR) processor is analyzed. A technique to determine the model order, which is required by the frequency estimation algorithms, is presented that does not distinguish between targets and clutter. Clutter region concept is introduced to identify targets from clutter. The possibility to use these algorithms for target classification is briefly explained after providing a literature survey on helicopter echoes.