Dissertations / Theses on the topic 'Range edge'

We propose and analyse a scheme for performing a long-range entangling gate for qubits encoded in electron spins trapped in semiconductor quantum dots. Our coupling makes use of an electrostatic interaction between the state-dependent charge configurations of a singlet-triplet qubit and the edge modes of a quantum Hall droplet. We show that distant singlet-triplet qubits can be selectively coupled, with gate times that can be much shorter than qubit dephasing times and faster than decoherence due to coupling to the edge modes. Based on parameters from recent experiments we argue that fidelities of $99\%$ could in principle be achieved, for a two-qubit gate taking as little as 20 ns

Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and, the Woods Hole Oceanographic Institution), 2004.
Includes bibliographical references (p. 37-40).
Laterally extensive, well-developed clinoforms have been mapped in Early Cretaceous deposits located in the northeastern 27,000 km2 of the Colville Basin, North Slope of Alaska. Using public domain 2-D seismic data, well logs, core photographs, and grain size data, depositional geometries within the Nanushuk and Torok formations were interpreted in order to constrain the transport conditions associated with progradation of the shoreline and construction of the continental margin out of detritus shed from the ancestral Brooks Range. Using STRATA, a synthetic stratigraphic modeling package, constructional clinoform geometries similar to those preserved in the North Slope clinoform volume (32,400 km3) were simulated. Sediment flux, marine and nonmarine diffusivities, and basin subsidence were systematically varied until a match was found for the foreset and topset slopes, as well as progradation rates over a 6 million year period. The ability of STRATA to match the seismically interpreted geometries allows us to constrain measures of possible water and sediment discharges consistent with the observed development of the Early Cretaceous clinoform suite. Simulations indicate that, in order to reproduce observed geometries and trends using constant input parameters, the subsidence rate must be very small, only a fraction of the most likely rate calculated from the seismic data. Constant sediment transport parameters can successfully describe the evolution of the prograding margin only in the absence of tectonic subsidence. However, further work is needed to constrain the absolute magnitude of these values and determine a unique solution for the NPR-A clinoforms.
by Christina Marie Kaba.
S.M.

The marsh rice rat (Oryzomys sp.) is a semiaquatic rodent native to wetlands in the southeastern United States. The northwestern-most part of the rice rat’s range extends to Illinois where rice rats are found in wetlands across the southern part of the state. Recent studies have shown that rice rats in the United States can be divided into two species: O. palustris and O. texensis, but the taxonomic status of rice rats in Southern Illinois is unclear. To resolve this, I sequenced cytochrome-b and the control region, two regions of mitochondrial DNA, for 16 rice rats and constructed a phylogeny using these new sequences and previously obtained O. palustris and O. texensis sequences. In contrast to previous morphological assessments, I found that rice rats in Southern Illinois should be classified as O. texensis. This would extend the range of O. texensis north and west from its current extent. Further investigation using nuclear loci will be needed to confirm this classification.

The sand lizard (Lacerta agilis) reaches the northern periphery of its distribution in south-central Sweden, where small, isolated relict populations occur in pine heath forests on sandy sediments. Modern forestry and fire suppression have reduced the amount of suitable open habitat for the species in this area and seem to be important for its decline. Main objectives of this thesis were to evaluate the efficiency of different management strategies, and if the sand lizard can function as an umbrella species for biodiversity conservation. Over a 16-year period, the estimated annual numbers of adult females in each of two study populations fluctuated between 23 and 3. Simulations of stochastic future population growth showed that the risk of extinction was highly dependent on population growth rate, which in turn was strongly affected by juvenile survival as indicated by elasticity analysis. Simulations of population growth for 50 years showed that the quasi-extinction risk (threshold ≤ 10 females) was > 56% for patches ≤ 1 ha; which is the observed average size of suitable habitat for inhabited patches during a 10-year period. In managed metapopulation networks with highly co-fluctuating local populations, among-population dispersal was not important to reduce extinction risks over a 50-year horizon. In the field the preferred microhabitat of sand lizards was successfully restored using tree felling and patch-soil scarification. The lizards gradually colonized the restored patches, and 16 years after restoration, sand lizards where mainly found there. Pine-heath area, and patch area within individual pine heaths, were of major importance for long-term population persistence at regional and landscape scales, respectively. Analyses of nested species subsets and an umbrella index suggest that the sand lizard can be a useful cross-taxonomic umbrella species on both scales for other red-listed species.

Yellow-cedar is a long-lived conifer of the North Pacific Coastal Temperate Rainforest region that is thought to be undergoing a continued natural range expansion in southeast Alaska. Yellow-cedar is locally rare in northeastern portions of the Alexander Archipelago, and the fairly homogenous climate and forest conditions across the region suggest that yellow-cedar’s rarity could be due to its local migrational history rather than constraints on its growth. Yellow-cedar trees in northern range edge locations appear to be healthy, with few dead trees; additionally, yellow-cedar tend to be younger than co-dominant mountain and western hemlock trees, indicating recent establishment in existing forests.

To explore yellow-cedar’s migration in the region, and determine if the range is expanding into unoccupied habitat, I located 11 leading edge yellow-cedar populations near Juneau, Alaska. I used the geographic context of these populations to determine the topographic, climatic, and disturbance factors associated with range edge population establishment. I used those same landscape variables to model suitable habitat for the species at the range edge. Based on habitat modeling, yellow-cedar is currently only occupying 0.8 percent of its potential landscape niche in the Juneau study area. Tree ages indicate that populations are relatively young for the species, indicating recent migration, and that most populations established during the Little Ice Age climate period (1100 – 1850).

To determine if yellow-cedar is continuing to colonize unoccupied habitat in the region, I located 29 plots at the edges of yellow-cedar stands to measure regeneration and expansion into existing forest communities. Despite abundant suitable habitat, yellow-cedar stand expansion appears stagnant in recent decades. On average, seedlings only dispersed 4.65 m beyond stand boundaries and few seedlings reached mature heights both inside and outside of existing yellow-cedar stands. Mature, 100 – 200-year-old trees were often observed abruptly at stand boundaries, indicating that most stand boundaries have not moved in the past ~150 years. When observed, seedlings were most common in high light understory plant communities and moderately wet portions of the soil drainage gradient, consistent with the species’ autecology in the region.

Despite an overall lack of regeneration via seed, yellow-cedar is reproducing via asexual layering in high densities across stands. Layering may be one strategy this species employs to slowly infill habitat and/or persist on the landscape until conditions are more favorable for sexual reproduction. This study leads to a picture of yellow-cedar migration as punctuated, and relatively slow, in southeast Alaska. Yellow-cedar’s migration history and currently limited spread at the northeastern range edge should be considered when planning for the conservation and management of this high value tree under future climate scenarios.

Current theory suggests that the life history of a species will vary in a predictable way from the range centre where habitat is likely to be optimal, to range peripheries where it is not. Moving towards cold water, high-latitude range edges, life history theory contends that individuals should exhibit reduced growth rates to an increased average maximum length, with delayed maturation and reduced somatic condition. In addition, increased recruitment variability should be observed towards range edges. Toothfish species Dissostichus eleginoides and D. mawsoni are large deep-water finfish predators of the Southern Ocean region. Both are found at the South Sandwich Islands in the South Atlantic Ocean, where they are situated on the edge of their distributional range. In this study, data collected on board commercial fishing vessels were used to describe the ecology, life history and dispersal patterns of range-edge toothfish populations, compared with those of range centre populations (South Georgia D. eleginoides and Ross Sea D. mawsoni). Two main research questions were addressed: 1. What limits the distribution of toothfish species populations at the South Sandwich Islands and how do range edge life history and population dynamics differ from those of range centre populations? 2. How can we use this information to more effectively manage the toothfish fishery at the South Sandwich Islands and other fisheries on range edge populations? A bioregional analysis made use of commercial longline data to resolve the position of the ecotone between the Antarctic and Subantarctic bioregions at the South Sandwich Islands. An abrupt transition was observed between the two bioregions around Saunders Island and this was spatially coincident for finfish and invertebrate communities, indicating a dramatic change in habitat type at this location. A correlative modelling analysis suggested that the formation of toothfish species range edges is influenced by the extent of sea ice cover and winter seawater temperature near the surface. However, differences between threshold values of ice and temperature at the South Sandwich Islands and the Ross Sea suggest that regional patterns in hydrography and topography may lead to the formation of range edges that do not necessarily correspond with niche requirements, with implications for studies evaluating species redistributions in response to climate change. Some, though not all of the hypothesised high latitude range edge life history traits were observed in South Sandwich Islands D. eleginoides. Increased maximum size was observed, though initial growth rates were similar to those of individuals at South Georgia and growth is clearly not a factor limiting productivity towards the high latitude range edge. There was no evidence at all for gonad maturation to spawning condition and this appears to relate to improved somatic condition, which would not normally be expected in range edge individuals. Highly episodic recruitment, also assumed to be a feature of range edge populations, was observed in South Sandwich Islands D eleginoides population and this is unlikely to be self-sustaining. This appears to be confirmed by an analysis of the otolith chemistry of D. eleginoides, where a similar chemical signature was observed at the cores of otoliths extracted from individuals captured at South Georgia and South Sandwich Islands. In addition a mark-recapture model was developed to estimate the migration rates of postrecruitment D. eleginoides between South Georgia and the South Sandwich Islands. Sexbiased migration of males away from the cold water range limit were also evident from an analysis of the sex ratio of the South Sandwich Islands population and have a considerable impact on resident population age structure. Accounting for the emigration of males greatly improved the accuracy of estimates from a CASAL assessment of the South Sandwich Islands D. eleginoides population. However the episodic nature of recruitment negatively impacted on the sustainable yield that could be taken according to CCAMLR harvest decision rules, which do not appear to be appropriate for this and other range edge toothfish stocks. Some aspects of range edge life history, including decreased growth rates, delayed maturation and episodic recruitment will impact on the productivity of a population such that it will be increasingly vulnerable to the impacts of exploitation. Where generalised patterns in range position effects on life history can be discerned, this information can be used to make predictions about the life history of exploited stocks that are otherwise data poor and also will allow for improved predictions as to how species will respond to changes in the environment such as those arising from climate change.

This dissertation focuses on sample-data modeling for double edge current programmed mode control (DECPM) and its application to high frequency and wide range DC-DC converters. Steady state conditions and subharmonic oscillation issues for DECPM are addressed. By combining the conventional peak and valley current programmed mode control, a sample-data model for DECPM is proposed. A small signal model for DECPM is developed by deriving the modulation gains (Fm) and the sampling gains (He) for DECPM from the proposed sample-data model. The sampling frequency dependence on the duty ratio and a large current loop gain at high frequency for DECPM are emphasized. The analytical results are verified by the simulation. Finally, DECPM is proposed as a method to control the high frequency and wide range DC-DC converters. A 10MHz four switch buck boost converter is implemented with DECPM to verify the viability of its application to high frequency and wide range converters.

Bat populations in the eastern United States are currently declining at unprecedented rates as a result of habitat loss, commercial wind energy development, and white-nose syndrome. Effective conservation of these declining populations requires knowledge of several aspects of summer and winter ecology, including daytime habitat use (day-roost selection and social behaviors), nocturnal habitat use (foraging habitat selection, prey selection, and prey abundance), and winter hibernation (torpor) patterns. This dissertation addresses these questions for Rafinesque’s big-eared bat (Corynorhinus rafinesquii), a species of conservation concern in the southeastern United States. Kentucky represents the northern edge of the range of Rafinesque’s big-eared bat, and summer and winter behaviors in Kentucky are likely to differ from what has been observed in southern portion of the range, where available habitats and climate are different. My research occurred in two study areas in Kentucky, Mammoth Cave National Park in central Kentucky, and the Ballard Wildlife Management areas in western Kentucky. This dissertation includes all of the work done in western Kentucky, where I radio-tagged 48 adult big-eared bats and documented daytime and nighttime habitat use. Also included is a portion of the work done in central Kentucky, focusing on hibernation patterns of 14 adult big-eared bats radio-tagged during the winter at Mammoth Cave. Data disseminated in this dissertation provide insights into the summer and winter ecology of Rafinesque’s big-eared bat in Kentucky, and can be used to manage populations threatened by habitat loss and white-nose syndrome.

Nous proposons des liaisons optiques en Silicium à faible coût utilisant des longueurs d'onde de propagation de 650 à 850 nm. La création de circuits intégrés optoélectroniques à grande échelle et de bus de données optiques au sein même des circuits intégrés, utilisant des composés Silicium CMOS, ont été envisagées présentant une voie prometteuse [1] - [3]. Dans les dernières tentatives de réalisation de systèmes optoélectroniques en CMOS, les technologies était principalement orientée sur l'utilisation des longueurs d'onde à 1550 nm [4] - [6], principalement en raison de la facilité de conception et de fabrication des guides d'ondes dans ce régime de longueur d'onde. Cependant, aucune source optique rapide efficace et aucun photo-détecteur Si ne sont disponibles à cette longueur d'onde de 1550 nm. Aujourd'hui, les solutions pour surmonter le problème sont principalement axées sur l'intégration de sources optiques basées sur des éléments du groupe IIIV reportés sur Silicium par liaison moléculaire [7a] - [7b].Si la source optique, le détecteur, les guides d'ondes et les capteurs pouvaient être réalisés sur la même puce CMOS Silicium, par exemple à une longueur d'onde de 750 nm, divers systèmes micro-photoniques sur puces, légers et miniaturisés, pourraient être conçus et réalisés. Alors que les sources optiques au Silicium ne sont peut-être pas encore au niveau de performance requis pour les communications à très haut débit, les systèmes optoélectroniques "tout-Silicium" à faible coût restent encore un excellent point de départ. Ces sources pourraient également conduire à un nouveau champ qui pourrait s'appeler «microsystèmes photoniques Si» ouvrant la voie à de nouvelles applications et produits notamment pour l'optique médicale, biomédicale, les interconnexions optiques et la biophotonique. Ces systèmes ne nécessitent de bande passante à très haute fréquence pour émettre, et les puissances d'émission de nos diodes électroluminescentes (LED) à avalanche peuvent être suffisantes pour assurer le fonctionnement de tels systèmes. Ce travail de thèse de doctorat traite donc des liaisons optiques SiGe / Si à faible coût en utilisant des dispositifs Photonique-Microondes tels que une source à Diode Electro-Luminescente (DEL) à avalanche en Silicium (SiAvLED) et Silicium-Germanium intégrée en technologie bipolaire, des guides d'ondes optiques en Nitrure de Silicium et en Oxyde de Silicium, des phototransistors bipolaires à hétérojonction (HPT) SiGe. Ce travail se concentre sur l'intégration combinée de sources optiques à l'échelle micrométrique, de guides d'ondes optiques et de détecteurs sur une même puce pour former une liaison de communication complète pour diverses applications iv impliquant des liaisons de courte longueur d'onde (750 nm à 950 nm). Les progrès fournis par ce travail par rapport aux travaux antérieurs pourraient être synthétisés comme suit:• La source optique, le guide d'ondes et le détecteur ont tous été intégrés et alignés sur la même puce, dans une technologie industrielle RF bipolaire SiGe 0,35μm, pour former une liaison optique ou optique micro-onde complète sur puce à la longueur d'onde de 750 nm.• Une série de liaisons de communication optique de deuxième génération de 50μm de longueur, utilisant des longueurs d'onde de propagation de 650 à 850 nm, a été conçue et réalisée en technologie SiGe bipolaire également. Des sources optiques, des guides d'ondes et des détecteurs de dimensions micrométriques ont tous été intégrés sur la même puce pour former une communication complète sur les liaisons micro-optiques. Des LED Si à base d'avalanche (Si Av LED), des contacts Schottky, des stratégies de densification TEOS, des guides d'ondes à base de Nitrure de Silicium et des technologies de détection bipolaire SiGe de pointe ont été utilisées comme stratégies de conception clés.• Le logiciel de simulation R-soft (Beam Prop) a été utilisé comme outil de simulation
We propose a low cost full-silicon optical links utilizing 650 – 850 nm propagation wavelengths. The creation of large-scale opto-electronic integrated circuits and optical data “highways” inCMOS integrated circuitry, utilizing Si CMOS compounds, have been envisioned and hold much promise [1] - [3] The latest attempts for realizing optoelectronic systems in CMOS technology have until now mainly been focused on utilizing wavelengths at 1550 nm [4] - [6], mainly because of the ease of design and fabrication of waveguides in this wavelength regime. However, no effective high-speed optical sources and Si detectors are available at this 1550nmwavelength. Today solutions to overcome the problem are mostly focused on the integration of group III-V elements based optical sources on Silicon through molecular bonding [7a] – [7b]. If optical sources, detectors, waveguides, and sensors could be realized on the same Si CMOS chip at, say, 750 nm wavelength, various low power consuming, light and miniature on-chip-based micro-photonic systems can be designed and realized. While Silicon optical sources may not yet be at the required performance level for very-high speed communications, the low cost “all silicon”opto-electronic systems still remain a great grail. These sources could lead as well to new field that could be appropriately named “Si photonic microsystems” opening the route to new sensing applications and products especially for the medical, biomedical optics, optical interconnect and bio-photonics field. These systems also do not require ultrahigh frequency bandwidths to transmit, and the emission powers of our avalanche Si light-emitting diodes(LEDs) may be sufficient to sustain the operation of such systems. This PhD thus deals with low cost SiGe/Si optical links using Microwave-Photonics devices such as, Bipolar integrated SiAvLED, Silicon Nitride and Silicon Oxide optical waveguides, SiGeHPTs, Si and SiGe/Si LEDs. It focuses on the combined integration of micron-scale optical sources, optical waveguides and detectors on the same chip to form a complete communication link for various applications involving short wavelength links (750nm to 950nm). The progress provided by this PhD to previous works could be synthesized as below:• Optical source, waveguide and the detector were all integrated and aligned on the same chip, in an industrial based technology, to form complete on-chip micro-optical links at750nm wavelength, with a SiGe radio frequency (RF) 0.35µm bipolar process.• A series of second generation of on-chip optical communication links of 50µm length, utilizing 650 – 850 nm propagation wavelengths, have been designed and realized inSiGe. Micron dimensioned optical sources, waveguides and detectors were all integrated ion the same chip to form a complete communication on-chip micro-optical links. Avalanche based Si LEDs (Si Av LEDs), Schottky contacting, TEOS densification strategies, Silicon-Nitride based waveguides, and state of the art SiGe bipolar detector technologies were used as key design strategies.• R-soft simulation software (Beam Prop) was used as a mathematical capable simulation tool to model various Silicon-Nitride optical waveguide structures, before the designing, the fabrication, characterization and testing of the device. Various device structures were modeled, simulation iterations were performed on several optical waveguide designed structures before the device design, and the devices were tested experimentally.• Best performances of the designed on-chip optical links show a conversion loss as low as30dB from source to detector with up to 500MHz in cut off frequency. The good alignment and the good efficiency of each device are then clearly achieved. Higher frequency performances are also envisaged from preliminary measurements

The study of biological invasions is not only essential to regulate their vast potential for ecological and economical harm, they offer a unique opportunity to study adaptive evolution in the context of recent range expansions into novel environments. The North American invasion of the gypsy moth, Lymantria dispar L., since its introduction in 1869 to Massachusetts, has expanded westward to Minnesota, northward to Canada, and southward to North Carolina. Fluctuating range dynamics at the southern invasive edge are heavily influenced by heat exposure over their optimal (supraoptimal) during the larval stage of development. We coupled genomic sequencing with reciprocal transplant and laboratory-rearing experiments to examine the interactions of phenotypic, genetic, and environmental variation under selective supraoptimal regimes. We demonstrate that while there is no evidence to support local adaptation in the fitness-related physiological traits we measured, there are clear genomic patterns of adaptation due to differential survival in higher temperatures. Mapping of loci identified as contributing to local adaptation in a selective environment and those associated with phenotypic variation highlighted that variation in larval development time is partly driven by pleiotropic loci also affecting survival. Overall, I highlight the necessity and inferential power gained through replicating environmental conditions using both phenotypic and genome-wide analyses.

The geographical distributions of many species are changing in response to rapid environmental change, and lags between the emergence and colonisation of new habitat areas are common. Given many species distributions are not at equilibrium with the environment, a greater understanding of the processes that underpin range expansion is required to predict where lags might emerge. Here I explore how population processes lead to emergent patterns of occupancy from the core to the edge of the species range. Working with water voles (Arvicola amphibius) in the UK, I carry out large scale surveys of a recovering metapopulation to explore the contribution of environment and the colonisation process in limiting range extent. I then use experimental translocations of water voles to quantify drivers of colonisation and local persistence, and the spatial scale over which these processes operate. I also explore the role of sociality and conspecific attraction in driving the formation of local populations at low landscape densities, and investigate the potential for between-individual variation in a behavioural trait to influence the formation of these spatial structures. Onward expansion was limited by the spatial scale of the colonisation process, and abrupt declines in occupancy at the range edge suggest that immigration increased the chance of local persistence. Social attraction led to build up of local populations, while more distant, equally suitable habitat area remained vacant. Using an individual based modelling approach, I then test the effect of different dispersal strategies on the rate of range expansion for biologically realistic mating systems. Mating finding requirements lead to slower expansion, though avoiding high density patches and mate-searching reduced these lags. Lags may emerge from processes across a range of spatial scales, though species translocations may offer a potential tool for mitigating these lags, and prevent substantial declines in geographical distributions.

We present investigation and designing of a system that interacts with big audience, sitting in a dimmed theater environment. The goal is to automatically detect audiences and some of their actions. Test results indicate that because of low light condition we can’t rely on RGB camera footage in a dimmed environment. We use Microsoft Kinect Sensor to collect data from environment. Kinect is designed to be used with Microsoft Xbox 360 for gaming purposes. It has both RGB and Infrared depth camera. Change in amount of visible light doesn’t affect data from depth camera. Kinect is not a strong camera so it has limitations that we should deal with. Viewing angles of both cameras and depth range of Infrared camera are limited. Viewing angles of depth camera are 43° vertical and 57° horizontal. Most accurate range of depth camera is 1 meter to 4 meters from camera. Non-infrared reflective surfaces cause gaps in depth data. We evaluate possibility of using Kinect camera in a large environment with big audience. “Dome 3D theater” in Norrkoping Visualization Center C, is selected as environment to investigate and test the system. We ran some tests to find the best place and best height for camera to have most coverage. Our system works with optimized image processing algorithms that use 3D depth data instead of regular RGB or Grayscale image. We use “libfreenect”, Open Kinect library to get Kinect sensor up and running. C++ and OpenGL are used as programing languages and graphics interface, respectively. Open GLUT (OpenGL Utility Toolkit) is used for system’s user interface. It was not possible to use Dome environment for every test during the programming period so we recorded some depth footage and used for later tests. While evaluating the possibility of using Kinect in Dome environment, we realized that implementing a voting system would make a good demonstration and test application. Our system counts votes after audiences raise their hands to vote for something.

La première partie de la thèse étudie le diagramme de phase d’une généralisation de la chaîne de Kitaev qui décrit un système fermionique avec un pairing p-wave à long rayon qui tombe avec la distance ℓ comme 1/ℓα. On a analysé les lignes critiques, les corrélations et le comportement de l’entropie d’entanglement avec la taille du système. Nous avons démontré l’existence de deux régimes massifs, (i) où les fonctions de corrélation tombent exponentiellement à de courtes distances et comme puissance à de longues distances (α > 1), (ii) où elles tombent à puissance seulement (α < 1). Dans la seconde région l’entropie d’intrication d’un sous-système diverge logarithmiquement. Remarquablement, sur les lignes critiques, le pairing à long rayon brise la symètrie conforme du modèle pour des α suffisamment petits. On a prouvé ça en calculant aussi l’évolution temporelle de l’entropie d’intrication après un quench. Dans la seconde partie de la thèse nous avons analysé la dynamique de l’entropie d’intrication du modèle d’Ising avec un champ magnétique qui dépend linéairement du temps avec de différentes vitesses. Nous avons un régime adiabatique (de basses vitesses) lorsque le système évolue selon son état fondamental instantané; un sudden quench (de hautes vitesses) lorsque le système est congelé dans son état initial; un régime intermédiaire où l’entropie croît linéairement et, ensuite, elle montre des oscillations du moment que le système se trouve dans une superposition des états excités de l’Hamiltonienne instantanée. Nous avons discuté aussi du mécanisme de Kibble-Zurek pour la transition entre la phase paramagnétique et antiferromagnétique
In the first part of the thesis, we propose an exactly-solvable one-dimensional model for fermions with long-range p-wave pairing decaying with distance ℓ as a power law 1/ℓα. We studied the phase diagram by analyzing the critical lines, the decay of correlation functions and the scaling of the von Neumann entropy with the system size. We found two gapped regimes, where correlation functions decay (i) exponentially at short range and algebraically at long range (α > 1), (ii) purely algebraically (α < 1). In the latter the entanglement entropy is found to diverge logarithmically. Most interestingly, along the critical lines, long-range pairing breaks the conformal symmetry for sufficiently small α. This can be detected also via the dynamics of entanglement following a quench. In the second part of the thesis we studied the evolution in time of the entanglement entropy for the Ising model in a transverse field varying linearly in time with different velocities. We found different regimes: an adiabatic one (small velocities) when the system evolves according the instan- taneous ground state; a sudden quench (large velocities) when the system is essentially frozen to its initial state; and an intermediate one, where the entropy starts growing linearly but then displays oscillations (also as a function of the velocity). Finally, we discussed the Kibble-Zurek mechanism for the transition between the paramagnetic and the ordered phase

Pine processionary moth (PPM, Thaumetopoea pityocampa) is an active range expanding pest species having significant economic impact in terms of tree growth and public health. A lot is known about its natural history although one important aspect of its life history, diapause, has been so far neglected in spite of its acknowledged importance in pest establishment and dynamics. A few questions related to diapause have been addressed in this PhD project. Although the existence of prolonged diapause (PD) was reported long ago, no study provided its maximum duration. We provide evidence of existence of at least 7 years of PD in one mountain population of PPM, and establish the importance of PD individuals in the sustenance of population density. This study underscores the importance of long-term surveillance of population for understanding the dynamics of PD. Although several studies have been conducted on the incidence of PD in PPM across it natural range, they were often published as forest service or forest health reports and not available to the large public. A collection of these reports, their validation and comparison with data from papers allowed to make a synthesis that included most of the pest range, including the sibling species Thaumetopoea wilkinsoni in the Near East. We suggest that winter conditions at the larval stage influence this decision. Data analysis suggests a strong U-shaped relationship between the incidence of PD and average winter temperature and a linear positive relationship between mortality and proportion of individuals in PD. The result contributes to the advancement of knowledge on the ecology, population dynamics and distribution of the PPM. Previous phenological models of PPM lack the description of dormant prepupal stage and its significance in synchronization of emergence. Besides, no study reported on the occurrence of diapause in PPM in a stage other than pupa. We show how with a weekly sampling during the two-month long procession period of pine processionary prepupae, it was possible to discover that prepupae differentially regulate their development time in such a way that moth emergence of short-lived adults resulted to be concentrated and synchronized in less than one month. Early descending individuals don’t pupate immediately, rather wait as diapausing prepupae for their late counterparts, whereas late-descending prepupae develop into pupae much faster. The finding of prepupal diapause and its significance in synchronization of emergence may improve the existing model of phenology and provide managers with a new tool to handle this pest. Diapause termination mechanism in both univoltine and prolonged diapausing individuals of PPM has been previously hypothesized based on the occurrence of a key period during the pupal stage. By using three proxies of metabolic activity, such as body temperature, O2 consumption, and weight loss, we confirm the hypothesis of existence of a key period (termination) in univoltine and prolonged diapausing individuals of PPM. This finding is a starting point for the study of diapause development in PPM from an ecological point of view. Compared to simple phenomenon of diapause, field of prolonged diapause in insects per se is not vast. A lot of questions regarding the regulation of prolonged diapause are still unresolved. When we consider PPM, the gap of knowledge in this regard is gigantic. Being an important pest of Mediterranean forests, PPM deploys diapause for its success. We know almost nothing about the regulation of diapause in this species. Despite that, this thesis attempted to start the effort of answering a few of thousands of questions on the regulation of diapause in PPM. This project has prepared the ground for several possible future works. Among them, some are: testing the findings in other populations, understanding genetic regulation of diapause and prolonged diapause, understanding the importance of climate change in regulating diapause, improving phenology models and using for predicting the effects of climate change under different scenarios.
La processionaria del pino (PPM, Thaumetopoea pityocampa) è una specie in fase di espansione dell’areale e che causa perdite importanti di crescita degli alberi nonché problemi sanitari all’uoma e altri animali. Nonostante molti studi siano stati condotti su questa specie, alcuni aspetti relativi alla diapausa sono stati finora trascurati anche se riconosciuti come importanti per l’affermazione della specie. Questa tesi si pone l’obiettivo di chiarirne alcuni. La presenza di diapausa prolungata (PD) in Th. pityocampa è nota da tempo ma mancano dati precisi sull’effettiva durata del fenomeno. Con questo studio si è potuto dimostrare che in una valle alpina al limite dell’areale la diapausa si estende fino a 7 anni, con ripercussioni significative sulla dinamica di popolazione. Ciò indica la necessità di una sorveglianza estesa delle popolazioni dell’insetto. Nell’areale della processionaria del pino sono stati svolti vari studi in cui la presenza di diapausa è stata accertata e quantificata, e alcuni di questi sono stati inclusi in rapporti interni di difficile reperibilità. L’accesso a questa informazione e la sua verifica puntuale hanno consentito di produrre una sintesi dei risultati, includendo anche la specie sorella Th. wilkinsoni diffusa in Asia Minore. I risultati mostrano che un fattore importante è rappresentato dalle temperature invernali cui sono esposte le larve. E’ stata infatti trovata una relazione a U tra temperatura invernale e frequenza della diapausa, associata a una maggiore mortalità per gli individui diapausanti. Tale risultato rappresenta un passo in avanti nella documentazione dell’effetto dei fattori ecologici sull’ecologia e sulla dinamica dell’insetto. I modelli di sviluppo disponibili per la processionaria del pino non hanno mai considerato lo stadio di prepupa e l’esistenza di una quiescenza/diapausa che porti a una migliore sincronizzazione degli sfarfallamenti. Grazie a un campionamento settimanale durante il periodo delle processioni di interramento è stato possibile accertare che il periodo di discesa è lungo circa il doppio rispetto allo sfarfallamento, e che le prepupe presentano una diapausa mirata a sincronizzare l’uscita degli adulti e quindi gli accoppiamenti. Il meccanismo si basa su un arresto dello sviluppo nei primi individui che scendono al suolo, che si riduce progressivamente durante il periodo. Queste nuove conoscenze sono di notevole importanza nella definizione di modelli di sviluppo e di previsione delle popolazioni dell’insetto. La conclusione della diapausa pupale in individui univoltini o in diapausa prolungata è stata associata alla presenza di un periodo chiave durante il quale l’individuo decide se proseguire nello sviluppo ad adulto o se rimanere in diapausa. Grazie a misure di alcune variabili non distruttive (temperatura superficiale, consumo di ossigeno, peso corporeo) è stato possibile mettere in evidenza per la prima volta l’esistenza di tale periodo in individui mantenuti a varie condizioni ambientali. Questo risultato rappresenta un enorme passo in avanti nelle conoscenza sulla regolazione della diapausa in questa specie. Nonostante la diapausa degli insetti sia in generale ben nota, le informazioni sulla diapausa prolungata sono scarse e molte domande giacciono irrisolte. Nel caso specifico della processionaria del pino questo ritardo è notevole e allo stesso tempo importante per la regolazione della dinamica di popolazione e quindi dei danni a piante e animali. Questo lavoro contribuisce a chiarire alcune aspetti importanti e apre la strada a studi mirati a conoscere la regolazione genetica della diapausa, gli effetti del cambiamento climatico, e lo sviluppo di modelli in grado di prevedere con affidabilità l’andamento demografico.

Edge detection is a basic image processing operation usually used in the first stage of the complex image processing systems, such as restoration, and its quality has a direct effect on the performance of the systems. The extraction of correct edges from a noise-contaminated image or an image with severe deformation is a challenging task. The objective of the work of this thesis is to develop an edge detection method to extract effectively edge signals from the images with the edge information seriously damaged while being acquired in high dynamic range (HDR) scenes. To achieve the objective, an edge detection method based on a multiple-high-pass-filtering process scheme has been proposed. Each of the filtering processes is designed to suit one of the signal deformation conditions, and is applied to the entire input image, instead of the designated regions, in order to spare the computation of image segmentation. A fusion process is then performed to merge the gradient maps generated by the multiple filtering processes into one. A detection procedure has been designed for a typical case of HDR images acquired with three different kinds of deformations due to the non-ideal characteristics of acquisition device. Based on the study of the characteristics, three high-pass filtering processes are designed to generate gradient signals with different modulations. A simple selection algorithm is developed for an easy fusion process. The results of the simulation with different types of HDR images have shown that, compared to some of most commonly used detection processes, the proposed one leads to a better quality of edge signals from severely deformed HDR images.

碩士
國立雲林科技大學
電機工程系
105
High dynamic range image(HDRI) is a real image that can show the actual scene. However, the HDRI can’t be displayed on the common display device, because the dynamic range of the common display device is very limited. Therefore, the tone mapping techniques have been developed to convert the HDRI into the low dynamic range image(LDRI). In this thesis, we propose a tone mapping technique with edge enhancement, and create a low complexity tone mapping technique that adjusts the illumination component to obtain a more pleasing image and is suitable for hardware implementation. Then, the Retinex theory is used to preserving the details of image. Finally, the HDRI is displayed on common device in real time. The proposed method also performs well in brighter and darker areas of output images. The details of those areas are both clear. First, we used software toolbox in Matlab to simulate the algorithm. Then, the algorithm was implemented with Verilog HDL in the hardware design. Secondly, we verified it on Altera Quartus II 13.1. The implemented results showed that the logic element count is 33K and the system works with a clock period of 17.11ns. Finally, we employed Synopsys Design Vision to synthesize our design with TSMC 0.13μm cell library. After synthesis, the clock frequency of the circuit is 100MHz. The logic gate count is 1100K.

碩士
國立雲林科技大學
電機工程系
104
High dynamic range image(HDRI) is a real image that can show the actual scene. However, the HDRI can’t be displayed on the common display device, because the dynamic range of the common display device is very limited. Therefore, the tone mapping techniques have been developed to convert the HDRI into the low dynamic range image(LDRI). In this thesis, we propose a weighted edge-preserving tone mapping technique. The proposed algorithm applies the weighted edge-preserving filter to estimate a smoother illumination, and create a low complexity tone mapping technique that adjusts the illumination component to obtain a more pleasing image and is suitable for hardware implementation. Then, the Retinex theory is used to preserving the details of image. Finally, the HDRI is displayed on common device in real time. The proposed method also performs well in brighter and darker areas of output images. The details of those areas are both clear. First, we used software toolbox in Matlab to simulate the algorithm. Then, the algorithm was implemented with Verilog HDL in the hardware design. Secondly, we verified it on Altera Quartus II 13.1. The implemented results showed that the logic element count is 22K and the system works with a clock period of 18.73ns. Finally, we employed Synopsys Design Vision to synthesize our design with TSMC 0.13μm cell library. After synthesis, the clock frequency of the circuit is 100MHz. The logic gate count is 579K.

Habitat disturbances play a major role in wildlife distribution. Disturbances such as loss of breeding habitat and fragmentation are of particular concern for Neotropical migrant songbird populations. Additionally, different avian species respond differently to the surrounding environment at different spatial scales. Thus, multi-scale studies on bird abundance and reproductive success is necessary for evaluating the effects of habitat alterations. The golden-cheeked warbler (Dendroica chrysoparia) is a Neotropical migrant songbird that breeds exclusively in central Texas. In 1990, the U.S. Fish and Wildlife Service listed the golden-cheeked warbler as endangered, providing habitat loss among the list of justifications. Habitat requirements for this species are known to include mature juniper-oak (Juniperus-Quercus) woodlands; however, relationships between habitat characteristics and golden-cheeked warbler reproductive success remain unclear. Whereas the majority of golden-cheeked warbler research has focused on areas in the center of the breeding range, little is known about interactions between warblers and the environment at the edge of the range. Therefore, it is important to understand these relationships for successful golden-cheeked warbler management. I investigated relationships between golden-cheeked warbler reproductive success and habitat characteristics, including canopy closure and tree species composition, at the study site and territory scale. My study took place within Kickapoo Cavern State Park and surrounding private properties in Kinney and Edwards counties in the southwest corner of the golden-cheeked warbler breeding range. I derived habitat characteristics from satellite imagery from the US Geological Survey National Land Cover Dataset (NLCD) and from field sampling. The NLCD provided data on canopy closure and tree species composition at a 30 m resolution. Additionally, I used spherical densitometers and transect evaluations to ground-truth data and take more detailed measurements. I determined reproductive success by nest monitoring and the Vickery index when nests could not be found. I monitored 80 territories across six study sites in 2009 and 2010. Reproductive success was 39.5 percent in 2009 and 59.4 percent in 2010. I found statistically significant results at the study site scale, whereas golden-cheeked warbler abundance increased as the portion of woodland increased. Similarly, I found that golden-cheeked warbler reproductive success increased at the study site scale as canopy closure increased. I did not find correlations between reproductive success and canopy closure or tree species composition at the territory scale. Results suggest that golden-cheeked warblers utilize a wider variety of habitat composition than previously thought, and habitat composition as a whole may not be the driving factors influencing warbler reproductive success in this region.

I examined the population dynamics of the provincially red-listed Brewer's Sparrow (Spizella breweri breweri) of British Columbia. This declining grassland bird reaches the northwestern limit of its breeding range in the province. My objectives were: 1) to explore spatial and temporal dynamics in fecundity and survival, 2) to model population viability based on these rates, 3) to examine the relative influences of vital rates on the population trend, and 4) to explore the relationship between the selection of nest site habitat characteristics and nest success. I found that seasonal fecundity was highest when the nest predation rate was low, the number of clutches/female was high and when breeding began later in the season. High seasonal fecundity alternated between the sites. The best site in 1998 became the least productive in 1999 and vice-versa, and a third site was most productive in 2000. The over-riding factor driving spatial and temporal variation in productivity was shifting rates of nest predation. However, elevation-related storm effects when breeding began early, and variation in the number of clutches laid, were partly responsible for this variation. Adult female survival varied between years, from a high of 66% in 1997-1998, an El Nino year, to a low of 26% from 1998-1999, a La Nina year. Survival did not vary between sites. A population viability model based on these demographic rates predicted that the population will decline to extinction within 100 years without immigration. For a bestcase scenario where mean adult survival was high and years of low survival occurred every 10 years, population growth rate (k) = 0.93. For a worst-case scenario where mean adult survival was low and years of low survival occur at random, X=0JS. Sensitivity analysis showed that the population growth rate was most sensitive to adult survival. Brewer's Sparrows selected nesting habitat that concealed nests. However, habitat variables related to concealment did not differ strongly between successful and depredated nests. Selected nest sites may not be the most successful because predation risk varies at larger spatial scales, and because the several generalist predators with differing search strategies cover all the possible safe havens.

碩士
國立成功大學
電機工程學系碩博士班
96
The goal of this thesis is to present a motion adaptive de-interlacing algorithm and its corresponding hardware implementation in light of its ability to determine inter-field or intra-field interpolation according to motion. The proposed de-interlacing algorithm consists of some detection methods such as motion detection, texture detection, and high frequency detection. Motion detection using motion history and the corresponding block can effectively detect the motion state. The appropriate spatial interpolation scheme using texture detection and high frequency detection can be selected according to different content data. The proposed interpolation methods are Wide Range Edge-based Line Average (WRELA), vertical filter, and field average. The proposed WRELA adaptively changes the search window to estimate the edge direction. In addition, WRELA also uses dominant edge detection and median filter to improve erroneous detection in a region with non-dominant directional edge and prevent the occurrence of bursting pixels, respectively. There are two processing elements in the proposed hardware architecture. The first is the detection block which can output control signal to select the interpolation method. The other is the interpolation block which can output the de-interlacing processing result. The proposed architecture is synthesized with UMC.18 μm technique cell library. The operating speed is 54 MHz.

碩士
國立臺灣大學
光電工程學研究所
103
We successfully measured the Si K-edge X-ray absorption near edge structure (XANES) spectra within the heavily Si doped InAs thin film grown by molecular beam epitaxy (MBE). By comparing the experiment results with the simulation spectrum of different local structures calculated by FEFF9 program, we realize the local structure of Si atoms within InAs. Si atom tend to replace the In atom (SiIn) in heavily Si doped InAs, becoming an n-type dopant. The distances between SiIn and 4 nearest As atoms will shrink to 2.230 A, and the SiIn will be ionized by an effective charge of +0.5. The p-type dopant or pair diffusion local structures of Si atom are unlikely to appear in the heavily Si doped InAs.

碩士
國立交通大學
物理研究所
99
Two mobility edges (MEs) are found in the instantaneous normal mode (INM) spectrum of a simple fluid, with one in the real-frequency branch and the other in the imaginary-frequency branch. Due to the complexity in calculations for the real-frequency ME, we only investigate the ME in the imaginary-frequency branch in this thesis. In terms of the multifractal analysis, the INM eigenvectors near a ME exhibit a multifractal nature with universal generalized fractal dimensions and the singularity spectrum. We calculate the singularity strengths of a Lennard-Jones (LJ) fluid for five system sizes. With the property that the singularity strengths near a ME reveal the system-size invariance, within numerical errors, we obtain the location of the ME in the imaginary-frequency branch of a LJ fluid. By changing the interaction range of the LJ fluid and different thermodynamic states in turn, we investigate the variation of the ME location with the temperature or density of the LJ fluid close to a glassy state and the variation with the interaction range of the LJ potential. According to our results, with the attractive force or by increasing the fluid density, the ratio of the imaginary-frequency localized INMs decreases. As the fluid temperature decreases, the ratio of the imaginary-frequency localized INMs also decreases. For the future works, the variations of the MEs in the glassy systems are worthy investigating.

abstract: This study explores how early modern humans used stone tool technology to adapt to changing climates and coastlines in the Middle Stone Age of South Africa. The MSA is associated with the earliest fossil evidence for modern humans and complex cultural behaviors during a time period of dramatic climate change. Human culture allows for the creation, use, and transmission of technological knowledge that can evolve with changing environmental conditions. Understanding the interactions between technology and the environment is essential to illuminating the role of culture during the origin of our species. This study is focused on understanding ancient tool use from the study of lithic edge damage patterns at archaeological assemblages in southern Africa by using image-based quantitative methods for analyzing stone tools. An extensive experimental program using replicated stone tools provides the comparative linkages between the archaeological artifacts and the tasks for which they were used. MSA foragers structured their tool use and discard behaviors on the landscape in several ways – by using and discarding hunting tools more frequently in the field rather than in caves/rockshelters, but similarly in coastal and interior contexts. This study provides evidence that during a significant microlithic technological shift seen in southern Africa at ~75,000 years ago, new technologies were developed alongside rather than replacing existing technologies. These results are compared with aspects of the European archaeological record at this time to identify features of early human technological behavior that may be unique to the evolutionary history of our species.
Dissertation/Thesis
Doctoral Dissertation Anthropology 2016