VictorJuiz/thesis huggingface dataset:
Concentric Circles for Orchestra
Keywords: 0413

The concept for my thesis, titled Concentric Circles, as well as for its organizational framework, is inspired by the ancient Chinese book of divination called the I-Ching (Book of Changes). The I-Ching consists of sixty-four hexagrams and related texts. The hexagrams are formed by combinations of six unbroken (yang –) and/or broken (yin --) lines arranged on top of one another in a vertical sequence. There are sixty-four possible combinations which are distributed into four dynamic sections: Great Yin, Lesser Yang, Lesser Yin and Great Yang. I designed the four movements of Concentric Circles based on this order, and employed these terms as subtitles for each movement. Dualism and pluralism, along with the basic principles of simplicity, variability, and persistence, offer numerous possibilities for the construction of the musical parameters, and for development in the work. Concentric Circles is a hybrid of essential elements taken from various Western and Eastern composers, such as symmetry, multiple orchestral layers, and quartal and quintal harmony. From Debussy and Ravel, I have drawn orchestral colours and instrumentation. From Messiaen and Takemitsu, I have attempted to create a timeless atmosphere, poetic expressions, subtle timbres, and sounds drawn from nature. The polymetric process reflects the influence of Nancarrow and Ligeti. The extremes of orchestral dimensions and levels are drawn from Xenakis, while the melodic syntax which interlocks the ending and the beginning of the adjacent musical phrases reflects Chinese folk music. The movement and energy within the individual notes, textures such as the sustained long notes with vibrato, the timbral inter-relationships among different instrumental groups, the proportion and balance between silence (pauses) and music are all informed by the aesthetics of Chinese calligraphy. Four selected hexagrams from four different dynamic distributions are assigned odd and even numbers, forming minor and major seconds, which are used to construct four musical scales. These four scales are the basic musical material of each movement. Each movement is designed with different and specific orchestral colours. For example, the first movement focuses on rustling texture and exquisite softness in the strings; the second movement seeks transparent colours and echo effects in the woodwinds, strings and percussion; the third movement conjures up an energetic dance ritual with multiple timbral and textural layers in brass and the lower instruments; the last movement concludes the whole work with orchestral tutti.
Symphony "Maligne Range"
Keywords: symphony
one-movement
program music
sonata form
orchestra
symphonic poem

In the summer of 2008, over two days, my wife and I hiked the Maligne Range (Skyline) trail, situated in the Canadian Rockies near Jasper, Alberta. The 45-km trail begins in a pine forest at Maligne Lake but soon rises above the tree line. From there it winds its way across two successively higher mountain passes. In between lies a sprawling meadow speckled with colourful flowers and criss-crossed by glacial creeks. At the halfway point, the trail switchbacks steeply to the very top of the range, a vantage point that affords spectacular views in all directions. But a storm set in just as we reached the peak. Unwilling to serve as lightning rods, we broke out into a run, finding shelter only as the trail drops off quickly on the other side of the range. The breathtaking views, ruggedness and diversity of terrain, whistling marmots and sense of isolation all left a strong impression on me. I was especially delighted to realize that the very topographical contour of the trail provides a basic plan for a large-scale sonata-form structure, one that builds up in waves of tension, culminating in a fierce storm at the top: the development. In a similar vein, after the stormy material subsides (as in Beethoven’s Sixth), the descent, recalling the ascent, but now abridged and in reverse order, serves as varied recapitulation. The result is a one-movement symphony in the tradition of Sibelius’s Seventh and Barber’s First. Essentially tonal, the harmonic language is enriched with polytonal accents, modal alterations, complex chords and the colouristic usage of collections and twelve-tone techniques. Polymetre, multi-stranded canons, metric modulation and controlled aleatoric techniques enliven the rhythmic plane. The work’s structure is organic, developed out of limited yet contrasting thematic material, with all programmatic elements assuming abstract structural roles. The symphony’s bright orchestration and rhythmic vitality is indebted to composers of the modern Russian school; its emotional sweep and extremes, to Shostakovich; the scoring and harmonic content of certain dissonant chords, to Varèse; and its sense of drama and breadth, to Beethoven and Sibelius.
Essays on Money, Trade and the Labour Market
Keywords: Macroeconomics
Offshoring
Income inequality

This dissertation consists of three essays in Macroeconomics. The first essay assesses the impact of offshoring on aggregate productivity and on labour market outcomes by developing a dynamic general equilibrium model in which workers acquire task-specific human capital. The dynamic nature of the model allows for differentiation between short and long run effects. While the welfare effects are unambiguously positive and independent of the skill-content of the offshored and inshored tasks, the distribution of the gains from trade critically depends on the time horizon. Workers with human capital specific to the inshored tasks gain over those performing offshored tasks in the short term. In the long run, the gains from trade are equally distributed among ex-ante identical agents. The model is calibrated to the U.S. economy; welfare gains from increased offshoring are found to be substantial even after taking into account losses in specific human capital for workers in the offshored occupations along the transition path. The second essay integrates the insight that exporting firms are typically more productive and employ higher skilled workers into a directed search model of the labour market. The model generates a skill premium as well as residual wage inequality among identical workers. Trade liberalization will cause a reallocation of workers both within and across industries, which will affect both types of inequality in a way that is consistent with findings from the empirical literature on trade and inequality. A calibrated version of the model can account for much of the effect of the Canada-U.S. Free Trade Agreement on the Canadian labour market. The final essay incorporates a distortionary tax into the microfoundations of money framework and revisits the optimum quantity of money. An optimal policy may consist of both a positive tax rate and a positive nominal interest rate: if the buyer's surplus share is inefficiently small, the intensive margin is distorted and the constrained optimal policy combines a sales tax with a money growth rate above that prescribed by the Friedman rule. Monetary, but not fiscal, policy alters the agent's bargaining position, leaving a special role for a deviation from the Friedman rule.
Three Essays in Industrial Organization and Labor Economics
Keywords: economics
industrial organization
labor economics
mobile phones
video consoles
new goods
structural estimation
regulation

The dissertation is comprised of three papers. In the first two Chapters, I analyze the importance of competition, preference heterogeneity, and socio-economic/country-specific factors to explain the differences in penetration rates of mobile phone services across EU Member States. Chapter 1 presents a model of demand and supply for mobile phone services in which products are perceived as homogenous but consumers are heterogeneous with respect to their valuation of the services. Once a service is purchased, consumers (temporarily) leave the market. The parameters which govern the distribution of preferences are allowed to vary by country and will be estimated as part of the demand specification. The model matches the data well and is able to replicate the observed u-shape in the coefficient of variation in penetration rates over the sample period. Using the demand parameters, consumer acquisition costs are backed out and counterfactual experiments performed. I find that preference heterogeneity and differences in the cost of consumer acquisition explain most of the variation in penetration rates across countries. Competition and other control variables, such as the price of fixed-line calls, play only a minor role. In Chapter 2 I relax the assumption that firms are perceived as homogenous and model them as differentiated products. I incorporate endogenous population weights in a standard random coefficients logit model to capture changes in the demographic composition of potential buyers over time due to the (temporary) market exit of adopters. Compared to the results of Chapter 1, I find a larger role of competition and a smaller impact of the (net) cost of consumer acquisition in explaining differences in mobile phone services diffusion. In the third Chapter, I analyze the effect of a product introduction on labor supply. I demonstrate that it is possible to overcome many of the limitations associated with the lack of individual level purchase data by focusing on teenage labor supply and the introduction of video game consoles. I find that 16- to 17-year old male teenagers significantly increase their hours of work in the months prior to video console introductions beyond the usual male-female difference.
Ensuring Safe Exploitation of Wind Turbine Kinetic Energy : An Invariance Kernel Formulation
Keywords: invariance kernel
planar systems
kinetic energy
wind turbine
stability
smoothing
inertia
frequency regulation

This thesis investigates the computation of invariance kernels for planar nonlinear systems with one input, with application to wind turbine stability. Given a known bound on the absolute value of the input variations (possibly around a fixed non-zero value), it is of interest to determine if the system's state can be guaranteed to stay within a desired region K of the state space irrespective of the input variations. The collection of all initial conditions for which trajectories will never exit K irrespective of input variations is called the invariance kernel. This thesis develops theory to characterize the boundary of the invariance kernel and develops an algorithm to compute the exact boundary of the invariance kernel. The algorithm is applied to two simplified wind turbine systems that tap kinetic energy of the turbine to support the frequency of the grid. One system provides power smoothing, and the other provides inertial response. For these models, limits on speed and torque specify a desired region of operation K in the state space, while the wind is represented as a bounded input. The theory developed in the thesis makes it possible to define a measure called the wind disturbance margin. This measure quantifies the largest range of wind variations under which the specified type of grid support may be provided. The wind disturbance margin quantifies how the exploitation of kinetic energy reduces a turbine's tolerance to wind disturbances. The improvement in power smoothing and inertial response made available by the increased speed range of a full converter-interfaced turbine is quantified as an example.
Oversampling A/D Converters with Improved Signal Transfer Functions
Keywords: Oversampling A/D converters

This thesis proposes a low-IF receiver architecture suitable for the realization of single-chip receivers. To alleviate the image-rejection requirements of the front-end filters an oversampling complex discrete-time ΔΣ ADC with a signal-transfer function that achieves a significant filtering of interfering signals is proposed. A filtering ADC reduces the complexity of the receiver by minimizing the requirements of analog filters in the IF digitization path. Discrete-time ΔΣ ADCs have precise resonant frequency and clock frequency ratios and, hence, do not require the calibration or tuning that is necessary in the case of continuous-time ΔΣ modulator implementations. This feature makes the proposed discrete- time ΔΣ ADC ideal for multistandard receiver applications.
Coherent Two-dimensional Infrared Spectroscopy of Vibrational Excitons in Hydrogen-bonded Liquids
Keywords: water
infrared
ultrafast
exciton

The structure and structural dynamics of hydrogen bonded liquids were studied experimentally and theoretically with coherent two-dimensional infrared (2DIR) spectroscopy. The resonant intermolecular interactions within the fully resonant hydrogen bond networks give access to spatial correlations in the dynamics of the liquid structures. New experimental and theoretical tools were developed that significantly reduced the technical challenges of these studies. A nanofluidic flow device was designed and manufactured providing sub-micron thin, actively stabilized liquid sample layers between similarly thin windows. A simulation protocol for nonlinear vibrational response calculations of disordered fluctuating vibrational excitons was developed that allowed for the first treatment of resonant intermolecular interactions in the 2DIR response of liquid water. The 2DIR spectrum of the O-H stretching vibration of pure liquid water was studied experimentally at different temperatures. At ambient conditions the loss of frequency correlations is extremely fast, and is attributed to very efficient modulations of the two-dimensional O-H stretching vibrational potential through librational motions in the hydrogen bond network. At temperatures near freezing, the librational motions are significantly reduced leading to a pronounced slowing down of spectral diffusion dynamics. Comparison with energy transfer time scales revealed the first direct proof of delocalization of the vibrational excitations. This work establishes a fundamentally new view of vibrations in liquid water by providing a spatial length scale of correlated hydrogen-bond motions. The linear and 2DIR response of the amide I mode in neat liquid formamide was found to be dominated by excitonic effects due to largely delocalized vibrational excitations. The spectral response and dynamics are very sensitive to the excitonic mode structure and infrared activity distributions, leading to a pronounced asymmetry of linear and 2DIR line shapes. This was attributed to structurally different species in the liquid characterized by their degree of medium range structural order. The response is dominated by energy transfer effects, sensitive to time-averaged medium range structural order, while being essentially insensitive to structural dynamics. This work is the first to recognize the importance of energy transfer contributions to the 2DIR response in a liquid, and provides additional proof of the well-structured character of liquid formamide.
Neural Representation, Learning and Manipulation of Uncertainty
Keywords: Neural Computation

Uncertainty is inherent in neural processing due to noise in sensation and the sensory transmission processes, the ill-posed nature of many perceptual tasks, and temporal dynamics of the natural environment, to name a few causes. A wealth of evidence from physiological and behavioral experiments show that these various forms of uncertainty have major effects on perceptual learning and inference. In order to use sensory inputs efficiently to make decisions and guide behavior, neural systems must represent and manipulate information about uncertainty in their computations. In this thesis, we first consider how spiking neural populations might encode and decode information about continuous dynamic stimulus variables including the uncertainty about them. We explore the efficacy of a complex encoder that is paired with a simple decoder which allows computationally straightforward representation and manipulation of dynamically changing uncertainty. The encoder we present takes the form of a biologically plausible recurrent spiking neural network where the output population recodes its inputs to produce spikes that are independently decodeable. We show that this network can be learned in a supervised manner, by a simple, local learning rule. We also demonstrate that the coding scheme can be applied recursively to carry out meaningful uncertainty-sensitive computations such as dynamic cue combination. Next, we explore the computational principles that underlie non-linear response characteristics such as perceptual bias and uncertainty observed in audiovisual spatial illusions that involve multisensory interactions with conflicting cues. We examine in detail, the explanatory power of one particular causal model in characterizing the impact of conflicting inputs on perception and behavior. We also attempt to understand from a computational perspective, whether and how different task instructions might modulate the interaction of information from individual (visual and auditory) senses. Our analyses reveal some new properties of the sensory likelihoods and stimulus prior which were thought to be well described by Gaussian functions. Our results conclude that task-specific expectations can influence perception in ways that relate to a choice of inference strategy.
The Extensive and Condition-dependent Nature of Epistasis among Whole-genome Duplicates in Yeast
Keywords: Epistasis
Yeast
Genetic interaction
Protein interaction

Immediately following a gene duplication event, if both gene copies are to be fixed into a species’ genome there is a period of enhanced selection acting on either one or both duplicates (paralogs) that results in some extent of functional divergence. However, as redundancy among extant duplicates is thought to confer genomic robustness, a consequent question is: how much functional overlap exists between duplicates that are retained over long spans of evolutionary time? To examine this issue I determined the extent of shared protein interactions and protein complex membership for paralogous gene pairs resulting from an ancient Whole Genome Duplication (WGD) event in yeast, finding retained functional overlap to be substantial among this group. Surprisingly however, I found paralogs existing within the same complex tended to maintain greater disparities in expression, suggesting the existence of previously proposed “transcriptional back-up” mechanisms. To test both for existence of such mechanisms and for any phenotypic manifestation of their shared functional overlap I surveyed for the presence of aggravating genetic interactions between 399 WGD-resultant paralog pairs. While these paralogs exhibited a high frequency (~30%) of epistasis, observed genetic interactions were not predictable based on protein interaction overlap. Further, exposure to a limited number of stressors confirmed that additional instances of epistasis were only observable under alternate conditions. As only a small number of stress conditions were tested, the high frequency of genetic interactions reported appears to be a minimum estimate of the true extent of epistasis among WGD paralogs, potentially explaining the lack of overlap with protein interaction data. As it is impossible to survey an infinite condition space, Synthetic Genetic Array (SGA) screening of yeast strains carrying double-deletions of paralog pairs was used to assess functional redundancy among a group of the remaining non-epistatic paralog pairs. The resulting interactions demonstrated functional relationships in non-epistatic paralogs only obvious upon ablation of both duplicates, suggesting that these interactions had initially been masked through redundant function. These findings ultimately suggest an advantage to retained functional overlap among whole genome duplicates that is capable of being stably maintained through millions of years of evolutionary time.
Towards a Bezout-type Theory of Affine Varieties
Keywords: Affine varieties
Projective completion
Bezout theorem
Toric varieties
Degree like function
Filtration
Semidegree

We study projective completions of affine algebraic varieties (defined over an algebraically closed field K) which are given by filtrations, or equivalently, integer valued `degree like functions' on their rings of regular functions. For a polynomial map P := (P_1, ..., P_n): X -> K^n of affine varieties with generically finite fibers, we prove that there are completions of the source such that the intersection of completions of the hypersurfaces {P_j = a_j} for generic (a_1, ..., a_n) in K^n coincides with the respective fiber (in short, the completions `do not add points at infinity' for P). Moreover, we show that there are `finite type' completions with the latter property, i.e. determined by the maximum of a finite number of `semidegrees', by which we mean degree like functions that send products into sums. We characterize the latter type completions as the ones for which ideal I of the `hypersurface at infinity' is radical. Moreover, we establish a one-to-one correspondence between the collection of minimal associated primes of I and the unique minimal collection of semidegrees needed to define the corresponding degree like function. We also prove an `affine Bezout type' theorem for polynomial maps P with finite fibers that admit semidegrees corresponding to completions that do not add points at infinity for P. For a wide class of semidegrees of a `constructive nature' our Bezout-type bound is explicit and sharp.
Queries, Data, and Statistics: Pick Two
Keywords: Database Systems

The query processor of a relational database system executes declarative queries on relational data using query evaluation plans. The cost of the query evaluation plan depends on various statistics defined by the query and data. These statistics include intermediate and base table sizes, and data distributions on columns. In addition to being an important factor in query optimization, such statistics also influence various runtime properties of the query evaluation plan. This thesis explores the interactions between queries, data, and statistics in the query processor of a relational database system. Specifically, we consider problems where any two of the three - queries, data, and statistics - are provided, with the objective of instantiating the missing element in the triple such that the query, when executed on the data, satisfies the statistics on the associated subexpressions. We present multiple query processing problems that can be abstractly formulated in this manner. The first contribution of this thesis is a monitoring framework for collecting and estimating statistics during query execution. We apply this framework to the problems of monitoring the progress of query execution, and adaptively reoptimizing query execution plans. Our monitoring and adaptivity framework has a low overhead, while significantly reducing query execution times. This work demonstrates the feasibility and utility of overlaying statistics estimators on query evaluation plans. Our next contribution is a framework for testing the performance of a query processor by generating targeted test queries and databases. We present techniques for data-aware query generation, and query-aware data generation that satisfy test cases specifying statistical constraints. We formally analyze the hardness of the problems considered, and present systems that support best-effort semantics for targeted query and data generation. The final contribution of this thesis is a set of techniques for designing queries for business intelligence applications that specify cardinality constraints on the result. We present an interactive query refinement framework that explicitly incorporates user feedback into query design, refining queries returning too many or few answers. Each of these contributions is accompanied by a formal analysis of the problem, and a detailed experimental evaluation of an associated system.