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Perceptual grouping is essential to manage the complexity of real world scenes. We explore bottom-up grouping at three different levels. Starting from low-level grouping, we propose a novel method for oversegmenting an image into compact superpixels, reducing the complexity of many high-level tasks. Unlike most low-level segmentation techniques, our geometric flow formulation enables us to impose additional compactness constraints, resulting in a fast method with minimal undersegmentation. Our subsequent work utilizes compact superpixels to detect two important mid-level shape regularities, closure and symmetry. Unlike the majority of closure detection approaches, we transform the closure detection problem into one of finding a subset of superpixels whose collective boundary has strong edge support in the image. Building on superpixels, we define a closure cost which is a ratio of a novel learned boundary gap measure to area, and show how it can be globally minimized to recover a small set of promising shape hypotheses. In our final contribution, motivated by the success of shape skeletons, we recover and group symmetric parts without assuming prior figure-ground segmentation. Further exploiting superpixel compactness, superpixels are this time used as an approximation to deformable maximal discs that comprise a medial axis. A learned measure of affinity between neighboring superpixels and between symmetric parts enables the purely bottom-up recovery of a skeleton-like structure, facilitating indexing and generic object recognition in complex real images.

Results from numerical simulation were performed to study flow and heat transfer in two types of rotating multi-pass cooling channels. Second moment closure model was used to solve flow in domain generated from Chimera method. The first type was a four-pass channel with two different inlet settings. The main flowing channel was rectangular channel (AR=2:1) with hydraulic diameter (Dh ) equals to 2/3 inch (16.9 mm). The first and fourth channel were set as different aspect ratio (AR=2:1; AR=1:1). Reynolds number (Re) used in this part was 10,000. The rotating angle was set as 90 degrees. The density ratio was set as 0.115. The rotation number varied from 0.0 to 0.22. It was showed that inlet effect only caused influence to flow and heat transfer in first two passages. The second type was a four-pass channel with/without addition of vane in smooth turn portion. The main flowing channel was rectangular channel (AR=2:1) with hydraulic diameter (Dh) equals to 2/3 inch. The first and fourth passages were set to be square duct (AR=1:1). The Reynolds number (Re) used in this part was 20,000. Three rotation numbers were set here (Ro=0.0; Ro=0.2; Ro=0.4). The density ratio and rotating angle varied from 0.12 to 0.32 and from 45 degrees to 90 degrees respectively. According to numerical results, it was revealed that the addition of vane in smooth turn portion did not cause influence to part before it. However, it caused significant influence to flow and heat transfer in smooth turn portion and part after it.

Perceptual grouping is essential to manage the complexity of real world scenes. We explore bottom-up grouping at three different levels. Starting from low-level grouping, we propose a novel method for oversegmenting an image into compact superpixels, reducing the complexity of many high-level tasks. Unlike most low-level segmentation techniques, our geometric flow formulation enables us to impose additional compactness constraints, resulting in a fast method with minimal undersegmentation. Our subsequent work utilizes compact superpixels to detect two important mid-level shape regularities, closure and symmetry. Unlike the majority of closure detection approaches, we transform the closure detection problem into one of finding a subset of superpixels whose collective boundary has strong edge support in the image. Building on superpixels, we define a closure cost which is a ratio of a novel learned boundary gap measure to area, and show how it can be globally minimized to recover a small set of promising shape hypotheses. In our final contribution, motivated by the success of shape skeletons, we recover and group symmetric parts without assuming prior figure-ground segmentation. Further exploiting superpixel compactness, superpixels are this time used as an approximation to deformable maximal discs that comprise a medial axis. A learned measure of affinity between neighboring superpixels and between symmetric parts enables the purely bottom-up recovery of a skeleton-like structure, facilitating indexing and generic object recognition in complex real images.

Brachyspira species are bacteria that colonize the intestines of some mammalian and avian species with different degrees of pathogenicity. Brachyspira intermedia is a mild pig and bird pathogen with an unknown genomic sequence. In this project, we completed the genome of Brachyspira intermedia PWS/AT and did a comparative genomic analysis between B. intermedia PWS/AT and the already completed genomes of B. hyodysenteriae WA1, B. murdochii 56-150T and B. pilosicoli 95/1000. A table containing 15 classes of unique and shared genes was developed and analyzed in order to gain a better understanding of species-specific traits and clues behind the different degree of pathogenicity. Our result shows that genes are overall poorly annotated and further studies are of great importance for understanding different and shared properties. The largest number of unique features was found in B. intermedia and B. murdochii. B. hyodysenteriae and B. pilosicoli has most likely developed independently towards different biological niches and B. pilosicoli has undergone a major reductive evolution. One plasmid and six prophages were found in B. intermedia, where two of the phages appear to be capable of horizontal gene transfer. Further genome sequencing of more strains will probably increase the understanding of species-specific traits even more.

The presence of autonomous systems is becoming more and more common in today’s society.The contexts in which these kind of systems appear are numerous and the variations arelarge, from large and complex systems like autonomous mining platforms to smaller, moreeveryday useful systems like the self-guided vacuum cleaner. It is essential for a completelyself-supported mobile robot placed in unknown, dynamic or unstructured environments tobe able to localise itself and find its way through maps. This localisation problem is stillnot completely solved although the idea of completely autonomous systems arose in thehuman society centuries ago. Its complexity makes it a wide-spread field of reasearch evenin present days. In this work, the localisation problem is approached with an appearance based method forplace recognition. The objective is to develop an algorithm for fast pose hypotheses generationfrom a map. A database containing very low resolution images from urban environmentsis built and very short image retrieval times are made possible by application of imagedimension reduction. The evaluation of the database shows that it has real time potential becausea set of pose hypotheses can be generated in 3-25 hundreds of a second depending onthe tuning of the database. The probability of finding a correct pose suggestion among thegenerated hypotheses is as high as 87%, even when only a few hypotheses are retrieved fromthe database.

In this work, two innovations were demonstrated for in-situ 3D study of fatigue cracks and their closure as a function of applied load. The first related to improvements in how absorption microtomography is used to study fatigue cracks. The second is a new approach to 3D crack mapping relying on X-ray phase imaging and stereometric approaches. Absorption microtomography was used to determine crack surface positions. Crack opening was measured from absorption microtomography data both before and after crack extension and patterns of opening at several loads were analyzed for both cases. X-ray phase contrast imaging, an alternative approach to absorption microtomography, whose sensitivity to cracks is not strongly affected by the shape of the specimen, was also investigated. Increased sensitivity of phase imaging to cracks, compared to that of the absorption X-ray methods, allowed detecting crack positions up to the crack tip with no load applied to the sample. Stereometry reconstruction based on the phase microradiographs was carried out, and the results were compared with those of absorption microtomography on the same specimen. This study demonstrated that it is possible to reconstruct accurate 3D positions of features inside optically opaque sample by recording several X-ray phase microradiographs.

Jointless bridges are advantageous in removing mechanical joints which are a known cause of bridge deterioration. Elimination of joints provides a smoother riding surface and removes the possibility of de-icing salts penetrating the deck and corroding the deck reinforcing and underlying bridge superstructure. Jointless bridges are traditionally constructed by monolithically casting the entire bridge deck on beams after they have been erected. However, this process requires extensive in-field formwork and lengthy traffic closures. The Texas Department of Transportation proposes a new method of constructing jointless bridges using prefabricated girder-and-deck units connected on-site with cast-in-place closure pours. This new system will expedite construction and reduce disturbances to the traveling public. The objective of this experimental study was to investigate the behavior of the cast-in-place closure pour slab and to determine if it responds to wheel loads in the same way as a traditional monolithic continuous deck. The effects of the cold joints and discontinuous steel details are the focus of the research work.

Kim criticizes non-reductive physicalism as a suitable metaphysics of mind among things because of its failure on the issue of mental causation. The failure is especially present in the thesis of supervenience physicalism. Kim concludes that the causal powers of mental states can be reduced to the causal powers carried by the physical states realizing them. Such causal reduction might involve identity between mental properties and physical properties. I think this is not a necessary conclusion. I try to clarify some premises behind Kim’s analysis, regarding issues of irreducibility, downward causation and the structure of the physical domain. I think the main reason why Kim doubts the plausibility of non-reductive physicalism is his view that downward causation and non-reductive metaphysics indicate the physical domain being hierarchically divided into levels. It seems like Kim would take the opposite position regarding the structure of the physical: an undivided continuum. Yet, the question is if that position follows from the ontological tenet of physicalism. Finally, I conclude that not necessarily, and I develop some further implications and suggestions.

We read a novel one sentence at a time. The first scale of attention for even the longest novel is the play of forces within the thousands of individual sentences. This project aims to rescale the analysis of novelistic form, elucidating this play of forces: how do they shape attention, and how do structures of attention give rise to aesthetic experience? We recognize the importance of form in music and architecture in part because there is no referential content to distract us. When it comes to the realist novel, however, its rich referential field easily obscures the dynamics of experience created by form. This study seeks to elucidate those dynamics. Chapter One analyzes Austen’s long interval of tension. Austen’s capacious sentence stretches attention over an entire descriptive event, producing drama and crises even when events in the fictional world are characterized by equilibrium and serenity. With the syntax of the sentence unresolved, attention cannot rest. An achieved description thus has perceptual corollaries in temporal commitment, and in attention that is divided between the immediate claims of elaboration and the prospect of closure. In Dickens, microstructures of just one to three sentences elicit the sudden apercu. Like metaphor, the apercu emerges through our recognition of a meaningful relationship between actions, facts, and utterances. Dickens presents only the raw materials of discovery (say, by juxtaposing a character’s mutually contradictory statements), leaving to us the second-order activity of recognition (her disingenuousness). Chapter Three examines how Hardy employs linguistic analogues to represent the essential structure of perceptual experience. Chapter Four, on late James, shows how shifts in attention on two scales produce two distinct experiences. Shifts to the periphery of a scene act as a temporal ballast, adding weight to the perceived dimensions of the passage. Shifts within the sentence elicit intense perceptual involvement, even when that absorption exceeds what is warranted by the semantic plane. The essence of the novel’s referenced world can be preserved in memory, but linguistic form resists memory; it is immediate and ephemeral. During the act of reading, it is one of the novel’s greatest pleasures.