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No description available.

The interannual variability of tropical climates, including the tropical Marine climate, is best reflected in the rainfall activity of a given area. The effects of such variability are manifested in a number of ways on the physical landscape. However, this study focused on the ways in which the variability of the rainfall received on the Caribbean island of Trinidad, influenced the resulting streamflow discharges for different basins on the island. Various techniques such as time series analysis and spectral analysis, were used to identify the physical mechanisms, both local and non-variations in the regimes, such that the effects of easterly waves were observed in the rainfall; the Madden-Julian wave was identified in both the precipitation and streamflow regimes; there was evidence of a faster 14-25 day oscillation; and finally, the migration of the Intertropical Convergence Zone was found to be quasi-periodic in nature.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 88-97).

This research conducts a spatial and temporal analysis of the distribution of fecal coliform throughout the Capital Regional District (CRD) of southern Vancouver Island. The research is based on 17 years of historical data of stormwater samplings from 1995 to 2011 in the nearshore region. ArcGIS is used to map the fecal coliform data collected within and adjacent to nearshore areas to identify peaks above a regulated threshold. Heavily polluted areas are in Victoria downtown, Esquimalt and the southeastern shore of Oak Bay. Land-use data and drainage patterns are used to determine relationships between fecal coliform levels and land-use by considering relevant, temporally dependent factors. Temperature is positively correlated with FC level and precipitation is negatively correlated. The residential land use is identified as the main source of bacterial contamination. This analysis leads to a regression model that indicates two peaks (July and October) of FC level occur in a 12-month period and positively related to minimum temperature and cloud cover ratio. / Graduate

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<p>In the first part of this thesis we present a C++ implementation of an improved O(n log n) algorithm to compute runs, number of primitively rooted distinct squares, and maximal repetitions, based on Crochemore's partitioning algorithm. This is a joint work with Mei Jiang and extends her work on the problem. In the second part we present a C++ implementation of a linear algorithm to compute runs based on the Main's, and Kolpakov and Kucherov's algorithms following the strategy:</p> <p>1. Compute suffix array and LCP array in linear time;</p> <p>2. Using the suffix array and LCP array, compute Lempel-Ziv factorization in linear time;</p> <p>3. Using the Lempel-Ziv factorization, compute in linear time some of the runs that include all the leftmost runs following Main's algorithm;</p> <p>4. Using Kolpakov and Kucherov's approach, compute in linear time the rest of all the runs.</p> <p>For our linear time implementation, we partially relied on Jonathan Fischer's Java implementation.</p> / Master of Science (MSc)

It is important to evaluate periodic fluctuations in environment or climate recorded through time to better understand the nature of Earth's history as well as to develop ideas about what the future may hold. There exist numerous proxies by which these environmental patterns can be demonstrated and analyzed through various time scales; from sequence stratigraphic bundles of transgressive-regressive cycles that demonstrate eustatic changes in global sea level, to the geochemical composition of a skeleton that records fluctuations in ocean temperature through the life of the biomineralizing organism. This study examines some of the methods by which we can analyze environmental fluctuations recorded at different time scales. The first project examines the methods by which extrabasinal orbital forcing (i.e. Milankovitch cycles) can be tested in the rock record. In order to distinguish these patterns, computer generated carbonate rock records were simulated with the resulting outcrops tested using common methods. These simulations were built upon eustatic sea level fluctuations with periods similar to what has been demonstrated in the rock record, as well as maintaining the many factors that affect the resultant rock composition such as tectonics, subsidence, and erosion. The result demonstrated that substantially large sea level fluctuations, such as those that occur when the planet is in an icehouse condition, are necessary to produce recognizable and preservable patterns that are otherwise overwhelmed by other depositional factors. The second project examines the temporal distribution of the bivalve Semele casali from Ubatuba Bay, Brazil by using amino acid racemization (AAR) calibrated with ¹⁴C radiometric dates. This data set is one of the largest ever compiled and demonstrates that surficial shell assemblages in the area have very long residence times extending back in time 10,000 years. The area has had very little change in sea level and the AAR ratios which are highly temperature dependent could be calibrated across sites varying from 10 to 53 meters in water depth. Long time scales of dated shells provide us with an opportunity to study climate fluctuations such as El Niño southern oscillation. The third project describes a newly developed method for estimating growth rates in organisms using closely related species from similar environments statistically analyzed for error using a jackknife corrected parametric bootstrap. As geochemical analyses get more precise while using less material, data can be collected through the skeleton of a biomineralizing organism, thus revealing information about environmental shifts at scales shorter than a year. For such studies, the rate of growth of an organism has substantial effects on the interpretation of results, and such rates of growth are difficult to ascertain, particularly in fossilized specimens. This method removes the need for direct measures of growth rates and even the most conservative estimates of growth rates are useful in constraining the age ranges of geochemical intra-skeletal studies, thus elucidating the likely time period under analysis. This study assesses the methods by which periodic environmental fluctuations at greatly varying time scales can be used to evaluate our understanding of earth processes using rigorous quantitative strategies. / Ph. D.

Test and evaluation (TandE) is a critically important step before in-the-field deployment of radio-frequency (RF) hardware in order to assure that the hardware meets its design requirements and specifications. Typically, TandE is performed either in a lab setting utilizing a software simulation environment or through real-world field testing. While the former approach is typically limited by the accuracy of the simulation models (particularly of the anticipated hardware effects) and by non-real-time data rates, the latter can be extremely costly in terms of time, money, and manpower. To build upon the strengths of these approaches and to mitigate their weaknesses, this work presents the development of an FPGA-based TandE tool that allows for real-time pseudo-random aggregate signal generation for testing RF receiver hardware (such as communication receivers, spectrum sensors, etc.). In particular, a framework is developed for an FPGA-based implementation of a test signal emulator that generates randomized aggregate spectral environments containing signals with random parameters such as center frequencies, bandwidths, start times, and durations, as well as receiver and channel effects such as additive white Gaussian noise (AWGN). To test the accuracy of the developed spectrum generation framework, the randomization properties of the framework are analyzed to assure correct probability distributions and independence. Additionally, FPGA implementation decisions, such as bit precision versus accuracy of the generated signal and the impact on the FPGA's hardware footprint, are analyzed.This analysis allows the test signal engineer to make informed decisions while designing a hardware-based RF test system. This framework is easily extensible to other signal types and channel models, and can be used to test a variety of signal-based applications. / Master of Science / Test and evaluation (TandE) is a critically important step before in-the-field deployment of radio-frequency signal hardware in order to assure that the hardware meets its design requirements and specifications. Typically, TandE is performed either in a lab setting utilizing a software simulation or through real-world field testing. While the former approach is typically limited by the accuracy of the simulation models and by slower data rates, the latter can be extremely costly in terms of time, money, and manpower. To address these issues, a hardware-based signal generation approach that takes the best of both methods mentioned above is developed in this thesis. This approach allows the user to accurately model a radio-frequency system without requiring expensive equipment. This work presents the development of a hardware-based TandE tool that allows for real-time random signal generation for testing radio-frequency receiver hardware (such as communication receivers). In particular, a framework is developed for an implementation of a test signal emulator that allows for user-defined randomization of test signal parameters such as frequencies, signal bandwidths, start times, and durations, as well as communications receiver effects. To test the accuracy of the developed emulation framework, the randomization properties of the framework are analyzed to assure correct probability distributions and independence. Additionally, hardware implementation decisions such as bit precision versus quality of the generated signal and the impact on the hardware footprint are analyzed. Ultimately, it is shown that this framework is easily extensible to other signal types and communication channel models.

La modélisation des événements et de leurs propriétés temporelles concerne des types variés d’utilisateurs et de communautés scientifiques. Nous nous plaçons dans le cadre du paradigme Objet et construisons un méta modèle opérationnel servant de représentation pivot, indépendante du métier pour représenter des événements composites avec leurs propriétés structurelles et temporelles. Le méta modèle PTOM (Periodic Temporal Occurrence Metamodel) prend en compte l’expression de contraintes structurelles sur les événements, ou géométriques, topologiques et relationnelles sur la temporalité de leurs occurrences. Il privilégie la représentation en intension (vs extension) des occurrences d’événements périodiques. PTOM étend la norme ISO 19108 et s’adapte aux standards EventsML G2 et iCalendar. Sur un plan théorique, nous étendons les algèbres d’intervalles d’ALLEN et de LIGOZAT, et proposons un système de relations topologiques entre intervalles non convexes (ALLEN*) dont nous étudions les propriétés. Ces résultats sont intégrés dans PTOM. La première application de PTOM est la spécification de la sémantique du calendrier grégorien. Les éléments calendaires sont réintroduits en tant qu’événements périodiques dans PTOM, ce qui renforce son pouvoir expressif. PTOM a été mis en œuvre lors d’un projet ANR sur des corpus d’événements journalistiques (agences de presse) concernant les loisirs et la culture. L’Ingénierie Dirigée par les Modèles a été utilisée pour la conception et l’exploitation de PTOM. Cela permet de gérer la complexité, d’assurer la maintenabilité et la cohérence de l’ensemble et enfin, de générer automatiquement des interfaces pour les pourvoyeurs ou utilisateurs de données. / Modelling events with their temporal properties concerns many users and scientific communities. We adopted the Object paradigm and designed an operational metamodel which stands as a pivot business independent representation for composite events accompanied with their structural and temporal properties. PTOM metamodel (Periodic Temporal Occurrence Metamodel) accounts for structural constraints upon events and geometric, topologic or relational constraints upon their temporal occurrences. It gives prominence to intensional representations of periodic events occurrences vs extensional ones. PTOM extends ISO 19108 standard and fits EventsML G2 and iCalendar. From a theoretical viewpoint, we extend ALLEN’s and LIGOZAT’s interval algebras and propose a special set of topological relations between non convexintervals (ALLEN*), and study its properties. These results are part of PTOM. The first application of PTOM results in a specification of the Gregorian calendar semantics. Calendar elements are reinserted as periodic events in PTOM thus enhancing its expressiveness. PTOM was also experimented upon a corpus of journalistic (press agencies) events dedicated to leisure and culture at the occasion of an ANR project. Model Driven Engineering was extensively used for PTOM design and use.It allows to manage complexity and to ensure maintainability, consistency and eventually can automatically generate data provider or end user interfaces as well.