Alate morphs can benefit aphid populations by facilitating dispersal from deteriorating food sources and by escaping from natural enemies. Wing development, however, imposes constraints on fecundity. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an important economic pest in the U.S. and Canada. I conducted a series of laboratory and field experiments to determine the environmental factors inducing wing development in this species, and to determine the effects of asexual alate individual production on an A. glycines population under predation. My results reveal that wing induction in A. glycines occurs in response to interactions between crowding and decreased plant quality cues, and that alate aphid production benefits an aphid population under predation by increasing prevalence at a temporary cost to fecundity. My results contribute to the growing knowledge on the production of asexual alate aphids and provide insight into the biology of A. glycines as an agricultural pest. / May 2017

Les télécommunications laser en espace libre sont limitées en portée par la turbulence atmosphérique. L'optique adaptative, par la correction de la phase turbulente à l'émission du faisceau, a permis d'étendre leur domaine d'exploitation.Toutefois, sur de longues distances de propagation, cette correction n'est plus suffisante et il faut également précompenser l'amplitude du faisceau émis. De premières études numériques ont montré que le principe de retournement temporel, ou plus exactement de conjugaison de phase bidirectionnelle itérative, conduirait à des conditions satisfaisantes de focalisation du faisceau laser en fort régime de turbulence.Le principe de conjugaison de phase n'ayant été étudié que théoriquement jusque-là, mon travail de thèse s'est attaché à mettre en oeuvre un démonstrateur expérimental pour quantifier les performances de cette technique dans des conditions maîtrisées. En parallèle, une simulation de bout en bout de l'expérience a permis d'évaluer l'influence d'erreurs d'étalonnage sur les performances finales de la correction et de valider les résultats expérimentaux obtenus. Les points durs de la mise en oeuvre d'un système de télécommunications laser en espace libre ont ainsi été identifiés.L'ensemble de ces travaux constitue la toute première démonstration expérimentale du principe de retournement temporel optique. D'autres domaines d'application comme les lasers de puissance ou la propagation à travers des milieux biologiques très diffusants, nécessitant également de corriger le faisceau à l'émission, sont concernés. / Free Space Optical communications (FSO) are range limited due to atmospheric turbulence. Adaptive optics can mitigate turbulence effects by adding a phase modulation on the emitted laser beam. However, both phase and amplitude modulation are needed to perform long range FSO. Previous numerical studies have shown that iterative phase conjugation is an efficient modulation technique for lasercom systems.This PhD thesis is dedicated to the development and the realization of the first experimental demonstration of the iterative phase conjugation principle in a controlled turbulence environment. An optical bench, representative of a long range propagation through strong turbulence, has been scaled down to few-meters propagation in visible.Several methods for complex field measurement and modulation are numerically studied. Selected methods are implemented and tested, such as a novel focal plane technique for complex field measurement. Finally, iterative phase conjugation is performed and results cross-correlated with an end-to-end model representative of the optical bench.This work is the first experimental demonstration of the optical phase conjugation principle. Applications can be found in other fields than lasercoms, such as high power lasers or propagation through highly diffusing biological tissues, both in need of laser emission modulation.

Approved for public release, distribution is unlimited / This thesis sought to design and implement a low-cost, portable, Free-Space Optics (FSO) communications device for Ethernet applications. Under some circumstances such a device would have utility at a Combat Operations Center (COC), a Field Artillery Position, or wherever else fiber optic cable is used in garrison or field. The design was based on commercial off the shelf components originally designed for fiber optic applications. Based on a 155 megabits per second (Mbps) media converter, the design used two fiber optic transceivers, coupled to collimating lenses to pass data over free-space. Sustained data rate of 100 Mbps was achieved with full network functionality on the optical bench with a low-power (0.5mW) laser diode transmitter without focusing optics on the receiver. The laser diode power(mounted on device), was measured with acceptable losses up to 300 ft during testing using a photodiode with focusing optics. The findings indicate that the system with proper collecting optics could be optimized for free-space communication at short to moderate ranges. / Captain, United States Marine Corps

Technology for wireless information access has enabled innovation of 'smart' portable consumer devices. These have been widely adopted and have become an integral part of our daily lives. They need ubiquitous connectivity to the internet to provide value added services, maximize their functionality and create a smarter world to live in. Cisco's visual networking index currently predicts wireless data consumption to increase by 61% per year. This will put additional stress on the already stressed wireless access network infrastructure creating a phenomenon called 'spectrum crunch'. At the same time, the solid state devices industry has made remarkable advances in energy efficient light-emitting-diodes (LED). The lighting industry is rapidly adopting LEDs to provide illumination in indoor spaces. Lighting fixtures are positioned to support human activities and thus are well located to act as wireless access points. The visible spectrum (380 nm - 780 nm) is yet unregulated and untapped for wireless access. This provides unique opportunity to upgrade existing lighting infrastructure and create a dense grid of small cells by using this additional 'optical' wireless bandwidth. Under the above model, lighting fixtures will service dual missions of illumination and access points for optical wireless communication (OWC). This dissertation investigates multiple-input multiple-output (MIMO) optical wireless broadcast system under unique constraints imposed by the optical channel and illumination requirements. Sample indexed spatial orthogonal frequency division multiplexing (SIS-OFDM) and metameric modulation (MM) are proposed to achieve higher spectral efficiency by exploiting dimensions of space and color respectively in addition to time and frequency. SIS-OFDM can provide significant additional spectral efficiency of up to (Nsc/2 - 1) x k bits/sym where Nsc is total number of subcarriers and k is number of bits per underlying spatial modulation symbol. MM always generates the true requested illumination color and has the potential to provide better color rendering by incorporating multiple LEDs. A normalization framework is then developed to analyze performance of optical MIMO imaging systems. Performance improvements of up to 45 dB for optical systems have been achieved by decorrelating spatially separate links by incorporating an imaging receiver. The dissertation also studies the impact of visual perception on performance of color shift keying as specified in IEEE 802.15.7 standard. It shows that non-linearity for a practical system can have a performance penalty of up to 15 dB when compared to the simplified linear system abstraction as proposed in the standard. Luminous-signal-to-noise ratio, a novel metric is introduced to compare performance of optical modulation techniques operating at same illumination intensity. The dissertation then introduces singular value decomposition based OWC system architecture to incorporate illumination constraints independent of communication constraints in a MIMO system. It then studies design paradigm for a multi-colored wavelength division multiplexed indoor OWC system.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2019-02-25T23:03:33Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Zíngara Rocio dos Santos Eurich.pdf: 8759248 bytes, checksum: 68d4f63e6564948c318741b1d8432b4d (MD5) / Made available in DSpace on 2019-02-25T23:03:33Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Zíngara Rocio dos Santos Eurich.pdf: 8759248 bytes, checksum: 68d4f63e6564948c318741b1d8432b4d (MD5) Previous issue date: 2018-09-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Após uma longa trajetória, as praças permanecem presentes no desenho urbano e no imaginário de toda a população citadina. Sem perder sua principal função, a social, são trazidas como tema dessa pesquisa, com o objetivo de avaliar a qualidade destes espaços na cidade de Ponta Grossa, por meio de uma proposta metodológica. Para tanto foi necessário um levantamento bibliográfico sobre o tema além de metodologias capazes de avaliar qualiquantitativamente a arborização e infraestrutura das praças e analisar os aspectos espaciais, para que então fossem encontradas as variáveis necessárias para a composição de um Índice de Qualidade de Praças. Para se chegar ao índice final, denominado de IQP – Índice de Qualidade de Praças, foram considerados sub-índices ligados às principais funções das praças, denominados: Índice da Função Ambiental – IFA; Índice da Função Econômica – IFE e Índice da Função Social - IFS, uma vez que de acordo com a tese proposta, é o cumprimento destas funções que expressa a qualidade das praças. O intuito da pesquisa além de promover e valorizar os espaços livres públicos da cidade, sobretudo as praças, foi também apresentar o IQP como uma ferramenta de levantamento e análise dos dados. Todos os índices propostos variam de 0 a 1 e correspondem aos seguintes intervalos: 0 - 0,25 péssimo; 0,26 – 0,50 regular; 0,51 – 0,75 bom e 0,76 – 1 ótimo. Quanto aos resultados concernentes à distribuição espacial das praças verificou-se que algumas áreas consideradas pela Prefeitura Municipal de Ponta Grossa como praças se comportam como espaço sem função social direta, estas foram desconsideradas nas análises. Ao iniciar os resultados com uma análise geral das condições das praças verificou-se que há uma concentração das mesmas na área central da cidade, bem como nos bairros Uvaranas e Neves. Nas praças levantadas foram encontrados 1.936 indivíduos arbóreos dos quais 59,8% são de origem exótica. Quanto a infraestrutura, a iluminação, os caminhos e os bancos foram as estruturas mais frequentes. Quanto aos sub-índices o que obteve o maior valor foi o IFE que alcançou 0,85, o IFA alcançou 0,52 e o IFS 0,51. A partir do cálculo dos sub-índices obteve-se o IQP para a área urbana, por bairro e para cada praça. O IQP médio para as praças da cidade de Ponta Grossa resultou em 0,53, classificado como bom. O IQP mais alto foi apresentado pela praça Rotary Internacional com 0,89 e o valor mais baixo foi verificado para a praça Ambiental Jacobus Van Wilpe com 0,12. A partir dos resultados observa-se um cenário heterogêneo no que tange a qualidade desses espaços e observa-se que as variáveis da função social são as que necessitam de uma maior intervenção por parte do poder público, sendo a segurança, estética e distribuição as mais afetadas. Essas intervenções fariam com que Assim as praças conseguissem cumprir integralmente suas funções de grande importância para a população, assim como para todo o espaço urbano. / After a long trajectory, the squares remain present in the urban space and in the imaginary of the city population. Without losing its main function, the social, they are brought as a theme of this research, with the purpose of evaluating the quality of these spaces in the city of Ponta Grossa, through a methodological proposal. For this, it was necessary a bibliographic survey besides methodologies able of evaluating quantitative and quatitative the arborization and infrastructure of the squares and analyzing the spatial aspects, it was necessary found variables for the composition of a Quality Index of Squares. In order to reach the final index, denominated IQP - Quality Index of Squares, were considered sub-indices linked to the main functions of the squares, denominated: Index of the Environmental Function - IFA; IFS and Social Function Index - IFS, since according to the proposed thesis, it is the fulfillment of these functions that expresses the quality of the squares. The aim of the research, besides promoting and valuing the public spaces of the city, especially the squares, was also to present the IQP as a data collection and analysis tool. All proposed indexes vary from 0 to 1 and correspond: 0 - 0,25 bad; 0.26-0.50 regular; 0.51 - 0.75 good and 0.76 - 1 optimum. Regarding the results concerning the spatial distribution of the squares, it was verified that some areas considered by the City of Ponta Grossa as squares behave as space without direct social function, these were disregarded in the analyzes. When starting the results with a general analysis of the conditions of the squares it was verified that there is a concentration of the same in the central area of the city, as well as in the neighborhoods Uvaranas and Neves. In the squares were found 1,936 arboreal individuals of which 59.8% are of exotic origin. Infrastructure, lighting, sidewalk and banks were the most frequent structures. As for the sub-indices, the highest value was the IFE that reached 0.85 and IFA the index that obtained the lowest value, 0.52. Soon followed by the IFS with 0.51. From the calculation of the sub-indices the IQP was obtained for the urban area, by neighborhood and for each square. The average IQP for the squares of the city of Ponta Grossa resulted in 0.53, classified as good. The highest IQP was presented by Rotary Internacional with 0.89 and the lowest value was verified for Ambiental Jacobus Van Wilpe square with 0.12. From the results, a heterogeneous scenario is observed regarding the quality of these spaces and the variables require an intervention by the government, so that the squares can fully fulfill their functions of big importance for the population, as well as for all the urban space.

In the emerging industry of small unmanned vehicles, pioneered by small businesses and research institutions, a suitable combat system test platform is needed. Computer simulations are useful, but do not provide the definitive proof of effective operation necessary for deployment of a combat system. What is needed is an affordable simulated weapons system that enables live flight testing without the used of live weaponry. A framework is developed here for the construction of a simulated weapon using Free Space Optical (FSO) infrared communication. It is developed in such a way to ensure compatibility with a variety of platforms including ground and aerial vehicles, so that identical but configurable modules can be used on any vehicle that is to take place in a live combat simulation. A proof-of-concept implementation of this modular laser combat system framework is also presented and tested. The implemented system shows the value of such a simulated weapons system and future areas of improvement are also explored.

Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.

Over the last ten years, the number of laptop computers, personal digital assistants (PDAs) and other mobile terminals has massively increased. This evolution has led to a huge demand of wireless communications, in the purpose of avoiding wires and connectors to supply mobility in various places such as offices, homes, rail stations or airports. To date, this mobility is mainly offered by radiofrequency (RF) communications using Wi-Fi channels, with a maximum bitrate of 300 Mbps. However, new indoor applications such as non-compressed high-definition (HD) video transfer or remote hard-disk backup require much higher bandwidths (> 2Gbps). Such a bitrate can be transmitted using an optical wireless communications OWC system. In this thesis, a new architecture of OWC has been proposed and studied according to the GROWTH criteria (GReen Optical Wireless InTo Home network). This architecture is based on distributed free-space optical pico-cells in each room of the home interconnected by optical fibers and offering bitrates that exceed 1 Gbps. The work is divided into four parts: dimensioning of the systems and the selection of associated opto-electronics technologies, simulation of the hybrid optical channel (fiber optics + free-space) using the VPI Transmission Maker and Matlab softwares, choice of the wavelength and finally the experimental measurements to validate the performance of the system.

Wireless communication is facing an increasingly severe spectrum scarcity problem. Hybrid free space optical (FSO)/ millimetre wavelength (MMW) radio frequency (RF) systems and cognitive radios are two candidate solutions. Hybrid FSO/RF can achieve high data rate transmission for wireless back haul. Cognitive radio transceivers can opportunistically access the underutilized spectrum resource of existing systems for new wireless services. In this work we carry out accurate performance analysis on these two transmission techniques. In particular, we present and analyze a switching based transmission scheme for a hybrid FSO/RF system. Specifically, either the FSO or RF link will be active at a certain time instance, with the FSO link enjoying a higher priority. We consider both a single threshold case and a dual threshold case for FSO link operation. Analytical expressions are obtained for the outage probability, average bit error rate and ergodic capacity for the resulting system. We also investigate the delay performance of secondary cognitive transmission with interweave implementation. We first derive the exact statistics of the extended delivery time, that includes both transmission time and waiting time, for a fixed-size secondary packet. Both work-preserving strategy (i.e. interrupted packets will resume transmission from where interrupted) and non-work-preserving strategy (i.e. interrupted packets will be retransmitted) are considered with various sensing schemes. Finally, we consider a M/G/1 queue set-up at the secondary user and derive the closed-form expressions for the expected delay with Poisson traffic. The analytical results will greatly facilitate the design of the secondary system for particular target application. / Graduate

Quelques aspects de la géométrie des espaces LipschitzEn premier lieu, nous donnons les propriétés fondamentales des espaces Lipschitz libres. Puis, nous démontrons que l'image canonique d'un espace métrique M est faiblement fermée dans l'espace libre associé F(M). Nous prouvons un résultat similaire pour l'ensemble des molécules.Dans le second chapitre, nous étudions les conditions sous lesquelles F(M) est isométriquement un dual. En particulier, nous généralisons un résultat de Kalton sur ce sujet. Par la suite, nous nous focalisons sur les espaces métriques uniformément discrets et sur les espaces métriques provenant des p-Banach.Au chapitre suivant, nous explorons le comportement de type l1 des espaces libres. Entre autres, nous démontrons que F(M) a la propriété de Schur dès que l'espace des fonctions petit-Lipschitz est 1-normant pour F(M). Sous des hypothèses supplémentaires, nous parvenons à plonger F(M) dans une somme l_1 d'espaces de dimension finie.Dans le quatrième chapitre, nous nous intéressons à la structure extrémale de $F(M)$. Notamment, nous montrons que tout point extrémal préservé de la boule unité d'un espace libre est un point de dentabilité. Si F(M) admet un prédual, nous obtenons une description précise de sa structure extrémale.Le cinquième chapitre s'intéresse aux fonctions Lipschitziennes à valeurs vectorielles. Nous généralisons certains résultats obtenus dans les trois premiers chapitres. Nous obtenons également un résultat sur la densité des fonctions Lipschitziennes qui atteignent leur norme. / Some aspects of the geometry of Lipschitz free spaces.First and foremost, we give the fundamental properties of Lipschitz free spaces. Then, we prove that the canonical image of a metric space M is weakly closed in the associated free space F(M). We prove a similar result for the set of molecules.In the second chapter, we study the circumstances in which F(M) is isometric to a dual space. In particular, we generalize a result due to Kalton on this topic. Subsequently, we focus on uniformly discrete metric spaces and on metric spaces originating from p-Banach spaces.In the next chapter, we focus on l1-like properties. Among other things, we prove that F(M) has the Schur property provided the space of little Lipschitz functions is 1-norming for F(M). Under additional assumptions, we manage to embed F(M) into an l1-sum of finite dimensional spaces.In the fourth chapter, we study the extremal structure of F(M). In particular, we show that any preserved extreme point in the unit ball of a free space is a denting point. Moreover, if F(M) admits a predual, we obtain a precise description of its extremal structure.The fifth chapter deals with vector-valued Lipschitz functions.We generalize some results obtained in the first three chapters.We finish with some considerations of norm attainment. For instance, we obtain a density result for vector-valued Lipschitz maps which attain their norm.