VictorJuiz/thesis huggingface dataset:
Interpreting Faces with Neurally Inspired Generative Models

Becoming a face expert takes years of learning and development. Many research programs are devoted to studying face perception, particularly given its prerequisite role in social interaction, yet its fundamental neural operations are poorly understood. One reason is that there are many possible explanations for a change in facial appearance, such as lighting, expression, or identity. Despite general agreement that the brain extracts multiple layers of feature detectors arranged into hierarchies to interpret causes of sensory information, very little work has been done to develop computational models of these processes, especially for complex stimuli like faces. The studies presented in this thesis used nonlinear generative models developed within machine learning to solve several face perception problems. Applying a deep hierarchical neural network, we showed that it is possible to learn representations capable of perceiving facial actions, expressions, and identities, better than similar non-hierarchical architectures. We then demonstrated that a generative architecture can be used to interpret high-level neural activity by synthesizing images in a top-down pass. Using this approach we showed that deep layers of a network can be activated to generate faces corresponding to particular categories. To facilitate training models to learn rich and varied facial features, we introduced a new expression database with the largest number of labeled faces collected to date. We found that a model trained on these images learned to recognize expressions comparably to human observers. Next we considered models trained on pairs of images, making it possible to learn how faces change appearance to take on different expressions. Modeling higher-order associations between images allowed us to efficiently match images of the same type according to a learned pairwise similarity measure. These models performed well on several tasks, including matching expressions and identities, and demonstrated performance superior to competing models. In sum, these studies showed that neural networks that extract highly nonlinear features from images using architectures inspired by the brain can solve difficult face perception tasks with minimal guidance by human experts.

Keywords: facial expressions
neural network
deep belief net
restricted boltzmann machine
Advisor: Anderson, Adam K.
Chemical Modification of Cellulose Fibers and their Orientation in Magnetic Field

Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.

Keywords: Magnetic Cellulose
Cellulose Complex
Biofiber Orientation
Cellulose Biocomposite
Biodegradable Composite
Advisor: Sain, Mohini
Membership Change: A Network Perspective

This dissertation theorizes about why a team’s network structure might affect team performance immediately and over time when membership changes. I propose that the low substitutability of a central team member immediately disrupts the structure of interactions between remaining members and leaves the team without an important resource that is relied upon to facilitate team process. This performance loss is expected to decay as time elapses because the saliency of the event creates the focus and urgency required for the team to implement widespread systemic change. Dense interaction and task redundancy among core members in a centralized structure is expected to help offset this performance loss both immediately and over time. I examine the effect of network structure on initial team performance (performance immediately following member exit and entry) and performance over time (the rate of performance change following exit and entry) in professional hockey teams experiencing membership change due to player injury. Results show that the departure of a central player has a significant and negative effect on a team’s immediate performance, but the centrality of the absent member has a curvilinear effect on team performance over time. Teams that lost a central player experienced a drop in performance immediately after that player’s exit; but subsequently demonstrated an improvement in performance over time. Teams that lost a peripheral player experienced a more positive performance trajectory over time when compared with their performance before the exit, while the performance of teams that lost a mid-central player remains constant over time. While team centralization had no influence on initial team performance, over time it dramatically altered team outcomes such that, regardless of the departing player’s network position, teams with a centralized structure improved over time, whereas decentralized teams performed more poorly over time.

Keywords: Teams
Membership Change
Social Networks
Advisor: Berdahl, Jennifer
Casciaro, Tiziana
Investigation of the Function of the Meiotic Protein AHP2 in Arabidopsis thaliana

The ultimate purpose of this study was to investigate AHP2 protein function in Arabidopsis; AHP2 protein is known to form a heterodimer with MND1. But to do this an existing chromosome spreading protocol had to be modified to reproducibly provide large numbers of well preserved chromosomes and a multi-criteria meiotic staging method was developed to accurately identify chromosome spreads at specific prophase I substages. As well a technique for combined immuno-cytochemistry and fluorescent in situ hybridization (FISH) had to be developed. Coimmuno-localization of AHP2 and MND1 proteins, in wild type meiocytes, revealed synchronous temporal organization (signal initially peaks, for both, during zygotene) but spatially the AHP2 signal appeared exclusively as chromosome axis-associated foci whereas the MND1 signal was diffuse with some foci suggesting that MND1 may also be localizing to loop regions. This finding strongly suggests that MND1 also functions independently of AHP2 during meiosis. We coupled transmission electron microscopy (TEM) analysis of ultrathin sections of meiotic nuclei with light microscope (LM) analysis of chromosome spreads and demonstrated that ahp2 meiocytes fail to stabilize chromosome close alignment that normally occurs during zygotene. My method of combining 2-Bromo-5-deoxyUridine (BrdU) - determination of meiosis duration and the relative durations of each substage allowed us to calculate the absolute duration of each prophase I substage in wild type and revealed that early to mid-zygotene was prolonged in the ahp2 mutant. This finding was consistent with the ahp2 mutant’s overall lack of stabilized chromosome alignment. Scanning electron microscopy (SEM) showed that the Arabidopsis ahp2 short stamen filament was due to reduced cell elongation in filament parenchyma (epidermal) cells. Detection of illegitimate connections between chromosomes at anaphase I may trigger cell-to-cell signals that result in reduced epidermal cell elongation in the stamen filament. Finally, I report that the short arms of NOR-bearing chromosomes 2 and 4 homologously pair and synapse in the ahp2 mutant despite an overall lack of stabilized pairing. This NOR phenomenon has been observed in Drosophila but ours is the first report of the ability of NORs to locally induce pairing and synapsis in plants.

Keywords: AHP2
meiosis
HOP2
chromosome
Advisor: Hasenkampf, Clare
Perfecting the Law: Law Reform and Literary Forms in the 1590s and 1600s

This dissertation examines early modern literary engagements with the rhetorical and ethical dimensions of law reform. One of the most important mechanisms of social regulation in late-Elizabethan and early-Jacobean England, law reform was a matter of, first, the “perfection” of the organization and expression of existing laws, legal instruments, and legal processes. However counter-intuitively, these officially-sponsored reforms were calculated to prevent more radical innovations that would generate “inconveniences,” systemic contradictions and uncertainties that threatened the law’s ability to produce just results. Second, law reformers generated a discourse on “execution” that targeted the character of legal representatives. This tradition of character criticism, delivered directly from the Lord Keeper’s mouth or circulated through other legal-political, literary, theatrical, didactic, and religious works, encouraged officers’ conscientious execution of their duties and alerted the English public to the signs of the abuse of authority. Law reform created a distinct critical orientation toward legal and governing activities that was reproduced throughout a system of justice in which an extraordinary number of subjects participated. It was a critical orientation, moreover, that was refracted in literature sensitive to the implications of the socio-political dominance of legal language, traditions, and officers. The principles and practices of law reform—along with the conflicts and anxieties that inspired and sprang from them—were appropriated by amateur and professional writers alike. Close readings reveal that Inns-of-Court revellers, Francis Bacon, John Donne and Shakespeare all engaged deeply with the potential, as well as the ethical and practical limitations, of law reform’s central role in local and national governance. In the Gesta Grayorum and Donne’s “Satyre V,” the reveller and the satiric speaker improvise on legal forms to compensate for the law’s imperfections that threaten the security and prosperity of the English subject. In Shakespeare’s Measure for Measure and The Winter’s Tale, the character of the legal-political officer and reformer is tested as he attempts to put policies and principles into practice.

Keywords: Shakespeare
Law
John Donne
Measure for Measure
Satyre
satire
The Winter's Tale
Gesta Grayorum
Inns of Court
Early Modern Drama
Law reform
Francis Bacon
Nicholas Bacon
Advisor: Magnusson, Lynne
Technological Pedagogical Content Knowledge: Secondary School Mathematics Teachers’ Use of Technology

Although the Technological Pedagogical Content Knowledge (TPACK) framework has shown a lot of promise as a theoretical perspective, researchers find it difficult to use it in particular environments because the requirements of the framework change in specific contexts. The purpose of this study was to explore and produce more flexible ways of using the TPACK for inservice mathematics secondary teachers. Three such teachers at an urban public school were observed in their classrooms and interviewed about their experiences of teaching mathematics and integrating computer technology in their day-to-day activities. Each participant had over 10 years experience in teaching mathematics in secondary schools in Ontario, and expertise in using computers in mathematics curriculum. The research questions were: 1) How do secondary school mathematics teachers describe their ways of integrating technology? 2) What difficulties do teachers have when they try to integrate technology into mathematics classrooms? The findings from the first research question show that teachers displayed a high degree of integration of technology. Their activities were very clearly designed, conferring clear roles to the use of integrating computer technology in mathematics classes. Teachers had specific approaches to integrate computer technology: a) to allow students opportunities to learn and experiment with their mathematical knowledge; b) to help them pass the content to the students in the process of teaching mathematics; and c) to assess and evaluate students’ work, and give them feedback. The findings from the second research question reveal that teachers had difficulties in purchasing and maintaining the computer equipment. They had some difficulties in trying to integrate new technologies as these required time, preparation, and dedication. In addition, teachers had some difficulties in making students use computers in a significant way. The implication for teacher education is that inservice teachers should have opportunities to update their computer and pedagogical skills, a long term perspective in integrating technology in mathematics education, and professional and technical support from teaching colleagues and administrators. Finally, the integration of computer technology in mathematics requires more intensive teamwork and collaboration between teachers, technical support staff, and administrators.

Keywords: Technological Pedagogical Content Knowledge
Secondary Mathematics Education
Inservice Teachers
Integrating Technology in Mathematics Education
Advisor: McDougall, Douglas Emerson
The Diefenbaker Moment

This thesis locates John G. Diefenbaker’s electoral triumphs in the general elections of 1957 and 1958 and his subsequent world tour within the context of the revival of Conservative nationalism in the postwar period. To make his case against a Liberal government that had been in power for twenty-two years, Diefenbaker had to engage the public in a response to political events based on an appreciation of an abstract and not quite palpable threat to democracy and a national way of life. He did so by harnessing the persuasive techniques of public relations and the new medium of television—a powerful combination that Diefenbaker knew could most effectively tell and sell a national narrative. The signature he settled on was the “New National Policy.” The choice harkened back to a discourse of Conservative nationalism that spoke of the antiquity of his party ideology and rediscovered the heroes who founded the nation. The “New National Policy” was a therapeutic ethos designed to assuage voters’ fears about mass consumption, continentalism, communism, and the end of empire: it ensured that the greatness of events and men of the past could guarantee the ideas and values of the present; it was gendered in its construction of patriotic manhood, exalted motherhood, and icons of nationalist ideology; it was transnational in scope; it told of a relation of cause-and-effect that resembled a theory of history more than a blueprint for public policy; it was fashioned to disarm critical analysis because it conformed to the structures and traditions of storytelling and the clichés of historical memory. This thesis makes three interrelated arguments. First, it argues that the systems of values and meanings on which Diefenbaker drew cannot be understood by analyzing his personal foibles or tracing his rise and fall through a series of events. Partisan narratives are built out of the dialectical interchange between warring political ideologies and are stories fitted to character, circumstance, and experience. Second, it suggests that Diefenbaker was a transitional figure whose vision, message, leadership style, and public relations campaign seemed to best fit the barely discernable dimensions of the political and cultural change of the immediate postwar decades. Finally, by examining resurgence of Conservative nationalism in the context of imperial decline, it seeks to show that partisan narratives in English Canada in the 1960s cannot be understood outside of the larger transnational contexts in which they emerged.

Keywords: Canadian History
Cultural History
Intellectual History
Gender History
Advisor: Bothwell, Robert
Structural and Functional Characterization of the Soluble Cell Adhesion Molecule DdCAD-1in Dictyostelium discoideum

The cadA gene in Dictyostelium encodes a unique Ca2+-dependent cell adhesion molecule DdCAD-1. It is synthesized as a soluble protein in the cytoplasm and then transported to the plasma membrane by contractile vacuoles. The solution structures of Ca2+-free and Ca2+-bound DdCAD-1 reveals that it contains two β-sandwich domains, belonging to the βγ-crystallin and immunoglobulin fold classes, respectively. Whereas the N-terminal domain has a major role in homophilic binding, the C-terminal domain tethers the protein to the cell membrane. Although hydrophobic interactions constitute the major force for adhesion, electrostatic interactions may act as a ‘switch’ to regulate the homophilic binding by a change in electrostatic potential caused by the binding of Ca2+ to the three binding sites. To further investigate DdCAD-1 transport, DdCAD-1-GFP fusion proteins were expressed in cadA-null cells. Time-lapse microscopy revealed that DdCAD-1 was imported by invagination of the contractile vacuole membrane. The N-terminal, C-terminal domains, and two of the three Ca2+-binding site mutant forms of DdCAD-1 failed to enter the contractile vacuole, suggesting that Ca2+-binding and the integrity of DdCAD-1 are required for import. Indeed, proteins with altered conformation failed to enter the contractile vacuole, indicating that the import signal is integrated in the three-dimensional structure of DdCAD-1. Finally, we describe how the cadA gene acts as a single-gene green beard. In chimera experiments, cells expressing DdCAD-1 were more likely to form fruiting bodies than cadA-null cells on soil plates. Here cadA behaved as a single gene green beard. However, cadA exhibited anti-green beard behaviour on non-nutrient agar plates. Wild-type cells differentiated mostly into prestalk cells and eventually died, whereas the cadA-null cells survived as spores. DdCAD-1 was enriched in cell-cell contact regions of anterior cells, while it was mostly localized in the cytoplasm of posterior cells. The presence of DdCAD-1 on the cell surface of prestalk cells is crucial for cell sorting, which in turn explain the anti-green beard effect observed in chimeras containing cadA+ and cadA- cells. These observations demonstrate that DdCAD-1 plays a direct role in cell sorting through differential cell-cell adhesion which results from the differential distribution of DdCAD-1.

Keywords: Biochemistry
Cell Biology
Molecular Biology
Dictyostelium discoideum
Cell Adhesion
Unconventional Secretion
Morphogenesis
Sociomicrobiology
Advisor: Siu, Chi-Hung
Completion Delay Minimization for Instantly Decodable Network Coding

Instantly Decodable Network Coding (IDNC) is a subclass of opportunistic network coding that has numerous desirable properties for a wide spectrum of applications, namely its faster decoding delay, simpler coding and decoding processes, and no decoding buffer requirements. Nonetheless, IDNC suffers from two main problems that may limit its attractiveness, as an implementable solution in future wireless networks, against full network coding (FNC), widely studied in the literature. First, it cannot guarantee the decoding of a new packet at each receiver in each transmission, which may severely affect its completion delay. Second, it requires full feedback in order to operate properly, which may be prohibitive for several practical network settings. In this thesis, we aim to reduce the effect of these drawbacks by studying the problems of minimizing the IDNC completion delay in full and limited feedback scenarios. Since completion delay cannot be optimized only through local decisions in each of the transmissions, we first study the evolution of the IDNC coding opportunities and determine the strategies maximizing them, not only for one transmission, but for all future transmissions. We then formulate the completion delay problem as a stochastic shortest path (SSP) problem, which turns out to be of extremely large dimensions that makes its optimal solution intractable. Nonetheless, we exploit the structure of this SSP and the evolution of the coding opportunities to design efficient algorithms, which outperform FNC in most multicast scenarios and achieve a near-optimal performance in broadcast scenarios. However, since FNC still outperforms IDNC in some network scenarios, we design an adaptive selection algorithm that efficiently selects, between these two schemes, the one that achieves the smaller completion delay. To study the effect of feedback reduction, we formulate the completion delay minimization problem, for the cases of intermittent and lossy feedback, as extended SSP and partially observable SSP problems, respectively. We show that these new formulations have the same structure of the original SSP. We thus extend the designed algorithms to operate in intermittent and lossy feedback scenarios, after taking update decisions on the attempted and un-acknowledged packets. These redesigned algorithms are shown to achieve tolerable degradation for relatively low feedback frequencies and high feedback loss rates.

Advisor: Valaee, Shahrokh