Planet Earth is undergoing a rapid rate of ecosystem conversion and degradation and one of the major challenges of current environmental science is to contribute to the management and conservation of biodiversity through the development of tools for assessing environmental change. The main goal of this doctoral dissertation is to contribute to the scientific literature on remote sensing tools for monitoring tropical dry forests, which is one of most important global change frontiers. This thesis is composed of five chapters which have the goals of covering the following specific goals: 1) To estimate the extent and geographic distribution of the neotropical dry forest. 2) To evaluate the potential use of satellite-detected fires as deforestation predictors in tropical dry forest and 3) To evaluate the potential of remote sensing techniques to detect edge effects in tropical dry forest. Before assessing the main goals of the thesis, in chapter two, Integrating Remote Sensing and Biodiversity research, we stress out the necessity of integrated assessments using multiple spatial and spectral resolution sensors over a wide array of ecosystems in order to find relevant ecosystem properties that would be sensitive to species richness. Chapter three, Extent and Conservation of tropical dry forests in the Americas, describes a regional scale mapping effort using coarse-scale imagery (MODIS 500-m) of the extent and geographical distribution of tropical dry forests that introduces several innovations to previous assessments. Based on these techniques, the total current extent of tropical dry forest in the Americas is 519,597 Km2. I also found that 66% of the ecosystem has been already converted to other land uses while only 4.5 % of is under protected areas. Chapter four, MODIS Active fires and deforestation in tropical dry forest landscapes, we show correlations patterns between the number of MODIS Active Fires and forest cover change in four tropical dry forest landscapes in Latin America. At the Santa Cruz site (Bolivia), correlations were strong and significant while at Chamela Site (Mexico) and the Mata Seca site (Brazil) correlations were moderate but significant as well. In the Machango site (Venezuela), active fires showed no correlation to deforestation events. In general, our findings show that fires detected by the MODIS sensor may be used as predictors of deforestation in tropical dry forest ecosystems. Chapter five, Edge influence on canopy openness and understory microclimate in two Neotropical dry forest fragments, addresses one of the most characteristic features of fragmented tropical forests: the increase in disturbance near the edges of the fragment or what is known as edge effects. Results in gap fraction and Fraction of Intercepted Photosynthetically Active Radiation (FiPAR) show that edge influence at tropical dry forest sites extend to at least 300-m. Finally, Chapter Six, Remote sensing of edge effects in dry forest fragments using CHRIS/Proba Imagery, shows an assessment of changes in the fraction of intercepted photosynthetically active radiation (FiPAR) across four edge-to-interior transects in tropical dry forests fragments and their correlation to spectral vegetation indices (SVIs) computed from the hyperspectral and multiangular CHRIS sensor on board the Proba platform. Results show that the use of spectral vegetation indices for identifying and quantifying edge effects in tropical forests have the potential to improve modeling of forest disturbance in fragmented landscapes. The work contained in these five chapters address issues that are critical to the advancement of tropical dry forest monitoring. These studies contribute to the current scientific literature on the use and application of optical remote sensing tools, not only applicable in tropical dry forests, but for tropical forest conservation at the continental, regional and local level.

No description available.

An investigation into the effects of deforestation and habitat fragmentation on a central Amazonian frog community was carried out on the Biological Dynamics of Forest Fragments Project, (BDFFP) based in Manaus, Amazonas, Brazil. Three aspects of deforestation were investigated: the effects of fragmentation and reserve size, the influence of matrix habitat and the effects offorest edge on frogs in 10- hectare isolates. Very few frogs species were lost from fragments (regardless of size) following fragmentation and isolation for 7-10 years. Instead, frog species richness increased, with an average increase in 10 species per fragment. The increase in species was brought about by an increase in matrix associated species, some of which were present in the absence of their preferred breeding habitat. Different frog species had varied responses to fragmentation. The abundance of Eleutherodactylus fenestratus, a terrestrial breeder, increased significantly as fragment size decreased, and its abundance was significantly higher in both large and small fragments than in continuous forest. Colostethus stepheni, a semi-terrestrial breeder, was less abundant in fragments than continuous forest. Finally, Eleutherodactylus zimmermanae and Osteocephalus sp.A did not differ significantly in abundance among fragments, or between fragments and continuous forest. Multiple regression analysis indicated that variation in litter depth and canopy cover may explain the observed increase in E. fenestratus abundance in small fragments. Breeding success of pool breeders attracted to artificial pools was variable, but there was no evidence of reduced breeding success in fragments relative to primary forest. Overall, fragmentation appeared to affect the frog community less severely than other taxonomic groups. Species richness in tropical forest remnants showed a tendency to increase as a result of fragmentation, and only one of four species exhibited lowered abundance in fragments. The effects of fragmentation and subsequent small isolated populations of frog species in fragments was alleviated somewhat by the ability of central Amazonian frogs to utilise matrix habitat. Litter frogs, wallow breeders and upland forest pool breeders all displayed an ability to permeate, and in most cases become residents of matrix habitat. Both matrix with a history of cut and burn and matrix which was only cut supported a similar frog community. Thus, for central Amazonian frogs isolates were not truly isolated due to the ability of frogs to utilise matrix habitat. Litter frogs in 10- hectare isolates displayed an independence from edge related abiotic and biotic gradients. This independence was true for frog species richness, abundance and composition. Consequently, forest fragments are in effect larger for frogs than for other taxa who are constrained by edge effects to exist only within the core of large fragments. Colostethus stepheni was one species found to be negatively affected by habitat fragmentation. Abundance of Colostethus stepheni was significantly lower in fragments and matrix habitat compared to primary continuous forest. This species was also found to be sensitive to edge, with higher abundances recorded as distance from the edge increased. The community level approach adopted in this study, as opposed to intensive investigation of single species, may well have overlooked other' sensitive' species which show more subtle responses to habitat fragmentation than that of Colostethus stepheni. The ability to use matrix and the relative independence from edge related phenomena accounts for the resilience of central Amazonian frogs in a disturbed and fragmented landscape. However, with respect to matrix habitat, forest surveyed in this study has not been repeatedly cut or cut and burnt (with the exception of pasture-land where the frog community is depauperate). In other areas of the Amazon, away from the experimental plots of the BDFFP, matrix habitat is destroyed more frequently. More work is needed to determine the ability of central Amazonian frogs to utilise matrix habitat which is disturbed more frequently.

Project (D. Min.)--Perkins School of Theology, Southern Methodist University, 1974. / Includes bibliographical references (leaf 72).

Project (D. Min.)--Perkins School of Theology, Southern Methodist University, 1974. / Includes bibliographical references (leaf 72).

abstract: CMOS technology is expected to enter the 10nm regime for future integrated circuits (IC). Such aggressive scaling leads to vastly increased variability, posing a grand challenge to robust IC design. Variations in CMOS are often divided into two types: intrinsic variations and process-induced variations. Intrinsic variations are limited by fundamental physics. They are inherent to CMOS structure, considered as one of the ultimate barriers to the continual scaling of CMOS devices. In this work the three primary intrinsic variations sources are studied, including random dopant fluctuation (RDF), line-edge roughness (LER) and oxide thickness fluctuation (OTF). The research is focused on the modeling and simulation of those variations and their scaling trends. Besides the three variations, a time dependent variation source, Random Telegraph Noise (RTN) is also studied. Different from the other three variations, RTN does not contribute much to the total variation amount, but aggregate the worst case of Vth variations in CMOS. In this work a TCAD based simulation study on RTN is presented, and a new SPICE based simulation method for RTN is proposed for time domain circuit analysis. Process-induced variations arise from the imperfection in silicon fabrication, and vary from foundries to foundries. In this work the layout dependent Vth shift due to Rapid-Thermal Annealing (RTA) are investigated. In this work, we develop joint thermal/TCAD simulation and compact modeling tools to analyze performance variability under various layout pattern densities and RTA conditions. Moreover, we propose a suite of compact models that bridge the underlying RTA process with device parameter change for efficient design optimization. / Dissertation/Thesis / Ph.D. Electrical Engineering 2011

Bark beetles are major pests of pine forests in North America that can inflict considerable damage and cause severe economic loss. The checkered beetle Thanasimus dubius Fabricius (Coleoptera: Cleridae), an abundant predator in the Eastern USA and Canada, has been suggested to influence the dynamics of several bark beetles, including the economically important southern pine beetle (SPB), Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae). Because of the importance of T. dubius in pine forests, I studied several aspects of T. dubius biology including both its chemical and dispersal ecology. I first present an experiment that was conducted to improve the rearing system of T. dubius so that sufficient numbers of predators could be produced more efficiently for both behavioral and ecological studies. Improvements to the rearing method potentially could be achieved by adding a preservative to increase the shelf-life of the diet used to feed larval T. dubius thereby allowing feeding intervals to be extended. To evaluate this, I added sorbic acid, a preservative, to the larval diet at three different concentrations (0, 0.1 and 0.2%) and for two different intervals between feedings (2-3 vs. 5 days). Additionally, I measured potential deleterious effects of this preservative on predator performance (i.e., female fecundity). I then assessed the effect of this predator on SPB survival by releasing newly hatched T. dubius larvae at several densities (0, 50 100, and 200) on pine logs infested by SPB. I also studied the chemotactic response of this predator toward various volatiles such as prey pheromones or tree volatiles in a wind tunnel. I developed a method that associated upwind flight behavior and antennal behavior to quantify the relative attractiveness of each tested source of chemical. I then conducted three experiments to investigate the ability of individual T. dubius to respond to different prey olfactory signals (bark beetle pheromones) and assess their potential for learning. First, I examined individual predator preferences toward three major prey pheromones (ipsenol, ipsdienol, and frontalin) in a study that combined a mark-release-recapture experiment with a field choice test. I also measured the responses of individual wild T. dubius in a wind tunnel, which allowed the testing of a wider range of semiochemicals (frontalin, ipsenol, ipsdienol, sulcatol, and α-pinene). A final wind tunnel experiment tested the ability of naive predators to learn two prey pheromones, frontalin and ipsenol, that were presented alone or associated with a reward. In the last chapter, I quantified the dispersal of this predator and its behavior along an edge separating a pine forest from a non-suitable habitat. I analyzed T. dubius distribution and movement in the field relative to its bark beetle prey Ips grandicollis Eichhoff (Coleoptera: Curculionidae) and to the root feeder Dendroctonus valens LeConte (Coleoptera: Curculionidae). These three insects are associated with the phenomenon of red pine decline in the Great Lakes area. Thus, understanding the relative pattern of movements of these three beetles could provide considerable knowledge on the spatial and temporal progression of red pine decline by, for instance, assessing the connection between existing pockets. I estimated the dispersal quantiles for this predator relative to its bark beetle prey and determined whether dispersal behavior was relatively homogeneous (one kind of disperser) or heterogeneous (two kinds). In a second part, I sampled the abundance of T. dubius, I. grandicollis, and D. valens along transects set between a matrix area constituted by a clearing and a habitat zone composed of red pine forest. I further developed a diffusion model, including a constant k (corresponds to the ratio of densities along the edge), that permits characterization of beetle behavior around the boundary. Studies developed in the present dissertation, therefore, investigated several aspects of T. dubius ecology: predation on SPB, ability to respond to an olfactory signal, and dispersal traits. I first showed that augmentation with larval T. dubius can successfully reduce the SPB ratio of increase in infested pine logs. I also developed a system of rearing T. dubius that was more efficient and could allow larger numbers of predators to be produced. Sorbic acid did not reduce adult lifetime or size but did affect female fecundity (20 - 40% reduction). Increasing feeding time interval to 5 days (instead of 2-3 days) improved the efficiency of the system, even when sorbic acid was not added in the diet. Wind tunnel experiments present a methodology that could enable future quantification of the relative attractiveness of various semiochemical treatments. I identified a particular antennal behavior, which I called "stand up antennal" that was typically produced when the insect was attracted to a semiochemical. The choice tests in the field and the wind tunnel experiment using wild adults both showed that T. dubius individuals are generalists that are flexible in their response to a broad range of semiochemical signals (frontalin, ipsenol, ipsdienol, sulcatol, and α-pinene). I demonstrate that naive predators are more attracted toward ipsenol after having experienced conditioning with this kairomone via a reward. Finally, experiments on dispersal and edge behavior revealed that T. dubius and one of its common prey, the bark beetle I. grandicollis, exhibit a different pattern of movement within red pine stands and surrounding habitats. First, adult T. dubius can disperse substantially further (50% dispersed beyond 1.54 km) than I. grandicollis adults (50% dispersed beyond 0.13 km). Second, T. dubius was highly affected by the presence of an edge, showing a step-like pattern with very predators caught in unsuitable areas. Conversely, the behavior of I. grandicollis was less limited by such a boundary. As with T. dubius, the root colonizer D. valens showed a strong edge behavior that was characterized by avoiding matrix zones.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2008. / Submitted by Jaqueline Oliveira (jaqueoliveiram@gmail.com) on 2008-12-02T16:05:55Z No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-16T13:53:15Z (GMT) No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Made available in DSpace on 2009-02-16T13:53:16Z (GMT). No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Com a crescente demanda pelos serviços de pacote de dados sem fio, as operadoras móveis de rede 3G hoje enfrentam o desafio de oferecer novos serviços multimídia com exigências de qualidade de rede ao mesmo tempo em que devem utilizar de forma eficaz a largura de banda que possuem. Esses novos serviços requerem o aumento de banda e de throughput de dados, devido à natureza intrínseca de interatividade que possuem. Essa crescente demanda por banda e throughput fez com que os comitês de padronização das redes de terceira geração trabalhassem no sentido de atender essas necessidades tendo como resultado a especificação de melhores esquemas de modulação e codificação, além da introdução de mecanismos de controle de qualidade dos enlaces (LQC – Link Quality Control) mais avançados. Entre as diversas propostas para a evolução das redes 2G (2ª Geração) para 3G (3ª Geração), o GPRS (General Packet Radio Services) e o EDGE (Enhanced Data Rates for GSM Evolution) aparecem como soluções transitórias (conhecidas como redes 2,5G), mas efetivas, para as redes GSM existentes. Este trabalho propõe apresentar uma proposta de política de adaptação de enlace, que suporte serviços 3G, baseada no modelo GERAN (GSM EDGE Radio Access Network) definido pelo 3GPP (3rd Generation Partnership Project), e que permita controle de admissão de sessão na rede IMS (IP Multimedia Subsystem) utilizando o protocolo de sinalização IP (Internet Protocol) conhecido como SIP (Session Initiation Protocol). Essa proposta é baseada nos resultados teóricos e experimentais, medidos em campo, na rede real de uma operadora GSM/EDGE. _______________________________________________________________________________________ ABSTRACT / With the increasing demand for wireless packet data services, 3G wireless carriers today are faced with the challenge of offering multimedia applications with quality of service requirements while at the same time effectively utilizing precious wireless bandwidth. These new data services require increased bandwidth and data throughput, due to their intrinsic nature. This increasing demand for bandwidth and throughput has driven the work of third generation standardization committees, resulting in the specification of improved modulation and coding schemes, besides the introduction of more advanced link quality control mechanisms. Among the several proposals for the evolution from 2G to 3G, GPRS (General Packet Radio Services) and EDGE (Enhanced Data Rates for GSM Evolution) stand out as transitional solutions for existing GSM networks (it is also referred to as 2.5G system). This work considers to presenting a proposal of politics of link adaptation, that it support services of 3rd generation, based on GERAN model (GSM EDGE Radio Access Network) defined by 3GPP (3rd Generation Partnership Project), and allows to control session admission in subsystem IMS using a IP signaling protocol known as SIP. This proposal is based on the theoretical and experimental results, measured in the field, in a real network.

IoT has become tremendously popular. It provides information access, processing and connectivity for a huge number of devices or sensors. IoT systems, however, often do not process the information locally, rather send the information to remote locations in the Cloud. As a result, it adds huge amount of data traffic to the network and additional delay to data processing. The later feature might have significant impact on applications that require fast response times, such as sophisticated artificial intelligence (AI) applications including Augmented reality, face recognition, and object detection. Consequently, edge computing paradigm that enables computation of data near the source has gained a significant importance in achieving a fast response time in the recent years. IoT devices can be employed to provide computational resources at the edge of the network near the sensors and actuators. The aim of this thesis work is to design and implement a kind of edge computing concept that brings AI models to a small embedded IoT device by the use of virtualization concepts. The use of virtualization technology enables the easy packing and shipping of applications to different hardware platforms. Additionally, this enable the mobility of AI models between edge devices and the Cloud. We will implement an AI model inside a Docker container, which will be deployed on a FireflyRK3399 single-board computer (SBC). Furthermore, we will conduct CPU and memory performance evaluations of Docker on Firefly-RK3399. The methodology adopted to reach to our goal is experimental research. First, different literatures have been studied to demonstrate by implementation the feasibility of our concept. Then we setup an experiment that covers measurement of performance metrics by applying synthetic load in multiple scenarios. Results are validated by repeating the experiment and statistical analysis. Results of this study shows that, an AI model can successfully be deployed and executed inside a Docker container on Arm-Cortex-based single-board computer. A Docker image of OpenFace face recognition model is built for ARM architecture of the Firefly SBC. On the other hand, the performance evaluation reveals that the performance overhead of Docker in terms of CPU and Memory is negligible. The research work comprises the mechanisms how AI application can be containerized in ARM architecture. We conclude that the methods can be applied to containerize software application in ARM based IoT devices. Furthermore, the insignificant overhead brought by Docker facilitates for deployment of applications inside a container with less performance overhead. The functionality of IoT device i.e. Firefly-RK3399 is exploited in this thesis. It is shown that the device is capable and powerful and gives an insight for further studies.

The Internet-of-Things (IoT) is a network of interconnected devices with sensing, monitoring and processing functionalities that work in a cooperative way to offer services. Smart buildings, self-driving cars, house monitoring and management, city electricity and pollution monitoring are some examples where IoT systems have been already deployed. Amongst different kinds of devices in IoT, cameras play a vital role, since they can capture rich and resourceful content. However, since multiple IoT devices share the same gateway, the data that is produced from high definition cameras congest the network and deplete the available computational resources resulting in Quality-of-Service degradation corresponding to the visual content. In this thesis, we present an edge-based resource management framework for serving video processing applications in an Internet-of-Things (IoT) environment. In order to support the computational demands of latency-sensitive video applications and utilize effectively the available network resources, we employ edge-based resource management policy. We evaluate our proposed framework with a face recognition use case.