Enhanced automatic 2D-3D conversion using retinex in machine learning framework

In this paper, we present an approach for automatically convert images from 2D to 3D. The algorithm uses a color + depth dataset to estimate a depth map of a query color image by searching structurally similar images in the dataset and fusing them. Our experimental results indicate that the inclusion of a retinex based stage for the query image and the dataset images improves the performance of the system on commonly-used databases and for different image descriptors

Diphthong Synthesis using the Three-Dimensional Dynamic Digital Waveguide Mesh

The human voice is a complex and nuanced instrument, and despite many years of research, no system is yet capable of producing natural-sounding synthetic speech. This affects intelligibility for some groups of listeners, in applications such as automated announcements and screen readers. Furthermore, those who require a computer to speak - due to surgery or a degenerative disease - are limited to unnatural-sounding voices that lack expressive control and may not match the user's gender, age or accent. It is evident that natural, personalised and controllable synthetic speech systems are required. A three-dimensional digital waveguide model of the vocal tract, based on magnetic resonance imaging data, is proposed here in order to address these issues. The model uses a heterogeneous digital waveguide mesh method to represent the vocal tract airway and surrounding tissues, facilitating dynamic movement and hence speech output. The accuracy of the method is validated by comparison with audio recordings of natural speech, and perceptual tests are performed which confirm that the proposed model sounds significantly more natural than simpler digital waveguide mesh vocal tract models. Control of such a model is also considered, and a proof-of-concept study is presented using a deep neural network to control the parameters of a two-dimensional vocal tract model, resulting in intelligible speech output and paving the way for extension of the control system to the proposed three-dimensional vocal tract model. Future improvements to the system are also discussed in detail. This project considers both the naturalness and control issues associated with synthetic speech and therefore represents a significant step towards improved synthetic speech for use across society

Cross-Layer Pathfinding for Off-Chip Interconnects

Off-chip interconnects for integrated circuits (ICs) today induce a diverse design space, spanning many different applications that require transmission of data at various bandwidths, latencies and link lengths. Off-chip interconnect design solutions are also variously sensitive to system performance, power and cost metrics, while also having a strong impact on these metrics. The costs associated with off-chip interconnects include die area, package (PKG) and printed circuit board (PCB) area, technology and bill of materials (BOM). Choices made regarding off-chip interconnects are fundamental to product definition, architecture, design implementation and technology enablement. Given their cross-layer impact, it is imperative that a cross-layer approach be employed to architect and analyze off-chip interconnects up front, so that a top-down design flow can comprehend the cross-layer impacts and correctly assess the system performance, power and cost tradeoffs for off-chip interconnects. Chip architects are not exposed to all the tradeoffs at the physical and circuit implementation or technology layers, and often lack the tools to accurately assess off-chip interconnects. Furthermore, the collaterals needed for a detailed analysis are often lacking when the chip is architected; these include circuit design and layout, PKG and PCB layout, and physical floorplan and implementation. To address the need for a framework that enables architects to assess the system-level impact of off-chip interconnects, this thesis presents power-area-timing (PAT) models for off-chip interconnects, optimization and planning tools with the appropriate abstraction using these PAT models, and die/PKG/PCB co-design methods that help expose the off-chip interconnect cross-layer metrics to the die/PKG/PCB design flows. Together, these models, tools and methods enable cross-layer optimization that allows for a top-down definition and exploration of the design space and helps converge on the correct off-chip interconnect implementation and technology choice. The tools presented cover off-chip memory interfaces for mobile and server products, silicon photonic interfaces, 2.5D silicon interposers and 3D through-silicon vias (TSVs). The goal of the cross-layer framework is to assess the key metrics of the interconnect (such as timing, latency, active/idle/sleep power, and area/cost) at an appropriate level of abstraction by being able to do this across layers of the design flow. In additional to signal interconnect, this thesis also explores the need for such cross-layer pathfinding for power distribution networks (PDN), where the system-on-chip (SoC) floorplan and pinmap must be optimized before the collateral layouts for PDN analysis are ready. Altogether, the developed cross-layer pathfinding methodology for off-chip interconnects enables more rapid and thorough exploration of a vast design space of off-chip parallel and serial links, inter-die and inter-chiplet links and silicon photonics. Such exploration will pave the way for off-chip interconnect technology enablement that is optimized for system needs. The basis of the framework can be extended to cover other interconnect technology as well, since it fundamentally relates to system-level metrics that are common to all off-chip interconnects

Resonant and Time Resolved Spin Noise Spectroscopy of Electron Spin Dynamics in Semiconductors.

Determining the spin properties of novel materials is necessary for the development of proposed spin-based information processing devices, or spintronics. While existing optical techniques work for some semiconductors, they are ineffective for other strategic material systems. In this dissertation, we explore gallium arsenide bismuthide alloys and irradiated gallium arsenide using conventional methods. We then introduce the novel techniques of Resonant and Time Resolved Spin Noise which may enable optical studies of previously inaccessible materials. Gallium arsenide bismuthide has a large tunable spin-orbit splitting, which could be desirable for spintronic applications. Hanle effect measurements reveal that the product of the g factor and effective spin lifetime (gTs) ranges from 0.8 ns at 40 K to 0.1 ns at 120 K, while below 40 K there was negligible change. The temperature dependence of gTs shows evidence of thermally activated behavior attributed to hole localization at Bi or Bi cluster sites. Modern electronics are sensitive to radiation damage and require extensive modification for use in space, nuclear robotics, and other environments, but the effects of long term exposure on spin properties had not previously been investigated. Time Resolved Kerr Rotation measurements of irradiated gallium arsenide reveal robust spin behavior to 5 MeV protons up to a 10^14 p/cm^2 fluence, even as photoluminescence intensity decreases by two orders of magnitude. Spin noise measurements are sensitive and capable of surpassing more established methods. However, the majority of schemes are restricted to Fourier analysis, record all sources of noise, and suffer digitizing restrictions. Since digitization involves discrete binning, amplitude resolution is limited by background fluctuations. Our novel techniques, Resonant and Time Resolved Spin Noise, bypass these issues using ultrafast laser pulses in tandem with analog electronic calculations that remove the background prior to digitizing. In principle, our system's accessible bandwidth for spin dynamics is 10 THz with sub-nanoradian/ Hz^(1/2) signal resolution using commercially available components. We demonstrate this measurement technique on a bulk n-type gallium arsenide sample and extract values for the g factor and dephasing time that are consistent with results from Time Resolved Faraday Rotation and Resonant Spin Amplication.PhDApplied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113537/1/bpursley_1.pd

Development and novel applications of halogenating agents.

Organic halides are extensively utilized as synthetic intermediates in areas such as pharmaceuticals, agrochemicals, and material polymers. While many halogenating agents have been developed, they continue to have low efficiency or selectivity, are difficult to handle, and often have limited substrate scope. To address this issue, our laboratory has developed novel halogenating agents with improved stability and efficiency. In these studies, we demonstrated a novel application of halogenating reagent, HCl·DMPU, in the nitrile synthesis. We developed a novel method for C−SCF3/SeCF3 cross-coupling reactions using gold redox catalysis. We developed a novel trifluoromethylating agent in a cost-effective and highly efficient manner. We also attempted the development of dithiadication based electrophilic trifluoromethylating agents. With the objective of exploring other applications of HCl·DMPU beyond chlorination, we found a novel application of HCl·DMPU in one-pot conversion of aldehydes to nitriles. This method exhibited broad substrate scope with high yields for the aromatic, aliphatic, and α,β-unsaturated aldehydes incorporating various functional groups. We developed a novel application of halogenating agents like AgSCF3 and [(NMe4)(SeCF3)] in combination with commercially available gold catalyst [(MeDalphos)AuCl] for trifluoromethylthiolation (-SCF3) and trifluoromethylselenolation (-SeCF3) of the diverse array of aromatic, alkenyl and alkynyl halides and obtained the corresponding trifluoromethylthio and trifluoromethylseleno derivatives in good to excellent yields under mild reaction conditions . This protocol was successfully utilized in late-stage modification of various drug derivatives. In our quest of developing novel halogenating agents, we invented a newer version of Umemoto reagent II in one-pot synthesis from inexpensive starting material. This reagent is more powerful than Umemoto reagent II. and its applicability in the trifluoromethylation of various nucleophiles was demonstrated. In an attempt to explore the uncharted territory of trifluoromethylation, we designed and attempted to synthesize dithiadication electrophilic trifluoromethylating agents endowed with two transferable trifluoromethyl groups. However, our efforts to date have not produced satisfactory results

Synthesis and Photophysical Properties of Silsesquioxane Based Molecules and Polymers

Completely condensed polyhedral silsesquioxanes (SQs), [RSiO1.5]8,10,12, appended with organic conjugated chromophores can offer high symmetry, high thermal stability, highly red-shifted emissions and charge separation compared with the free chromophores, indicating unconventional conjugation in the excited state and involving the SQ cages. This dissertation presents the synthesis and characterization of unsymmetrical and incomplete SQ cages with organic chromophores as well as the SQ-based organic-inorganic hybrid polymers/oligomers with emphasis on the mapping structure-property relationships and understanding their unique photophysical properties for potential uses in optoelectrical devices. First, this dissertation describes the synthesis of corner-modified, corner-missing, double decker closed and open SQs via silylation of the respective silanol phenyl-SQ precursors. Subsequent iodination/bromination of the phenyl groups on the cages and then Heck coupling of the halogenated derivatives provides stilbene-functionalized SQs where stilbene is a model for conjugated chromophore. Open SQ cages with ~7 stilbene groups display essentially the same fluoresce behavior as found for symmetric closed octa-stilbene functionalized SQs, with absorption ~300 nm and emission ~410 nm. The red-shifts of ~60 nm in emission relative to the free chromophores demonstrate excited-state electronic communication between the π^* orbitals of the stilbenes and through the cages, which indicates removing a corner or breaking two opposing bridges has little effect on LUMO formation. Interestingly, when the cages have only 2 stilbenes attached, they show similar absorption and emission to stilbene itself; however, with quite high luminescence quantum yields (≥0.7 vs. ≈ 0.07) proving that there is a threshold for the excited state conjugation to occur but also demonstrating that the cage does affect photophysical properties nonetheless. Organic-inorganic hybrid polymers with SQs in the main chain are prepared via Heck cross coupling of di-vinyl functionalized double decker vinylMeSiO[PhSiO1.5]8OSiMevinyl and ladder vinylMeSiO[PhSiO1.5]4OSiMevinyl SQs with dibromo-aromatic tethers. Double decker SQ-based polymers/oligomers show red-shifted emission from model bis-dimethoxysilyldivinyl-aryl analogs in the range of 50-120 nm, again supporting the electronic communication along the polymer chain through the SQ cage in the excited state, even with two -(O)2Si siloxane bridges. Coincidentally, the non-cage ladder SQs derived polymers/oligomers exhibit even further red-shifted emission beyond analogous double decker polymers in the range of 20-50 nm, even with shorter chain lengths, suggesting more efficient electronic interaction in ladders. In both systems, copolymers with biphenyl, terphenyl and stilbene display high photoluminescent quantum yields up to 0.8, suggesting potential emitting components in optoelectronic devices. Double decker derived terpolymers are synthesized with alternating biphenyl and thiophene linkers via stepwise Heck cross-coupling with the goal of shifting emission wavelengths to towards the visible coincident with high quantum yields. The resulting terpolymers display emissions at 430 nm, intermediate between those of the respective copolymers rather than emission from both units as would be expected from physical mixtures. This again provides further evidence for excited-state conjugation along polymer chains and through cages via disiloxane conjugated linkers. In addition, the quantum yields of the terpolymers DD-thiophene-DD terphenyl and DD-thiophene-DD-stilbene improve from 0.09 for the DD-co-thiophene copolymer to 0.20 and 0.24 respectively, providing successful examples of novel combination of improved quantum yields as well as longer-wavelength emission around 480 nm and new opportunities to tailor photophysical properties by modifying structures. Lastly, ‘hairy polymers’ are prepared via further functionalization of halogenated phenyl groups to stilbenes on the SQ cages in the main chain of hybrid polymers to explore possible 3-dimentional conjugationPHDMaterials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169792/1/junguan_1.pd

Chromosome territory position and active relocation in normal and hutchinson-gilford progeria fibroblasts

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Radial chromosome positioning in interphase nuclei is non-random and can alter according to developmental, differentiation, proliferation or disease status. The aim of this thesis is to understand how chromosome re-positioning is elicited and to identify the nuclear structures that assist this re-localisation event. By positioning all human chromosomes in primary fibroblasts that have left the proliferative cell cycle, the study within this thesis has demonstrated that in cells made quiescent by reversible growth arrest, chromosome positioning is altered considerably. Upon removal of serum from the culture medium, chromosome re-positioning took less than 15 minutes, required energy and was inhibited by drugs affecting the polymerization of myosin and actin. The nuclear distribution of nuclear myosin 1β was dramatically different in quiescent cells as compared to proliferating cells. If the expression of nuclear myosin 1β was suppressed using interference RNA procedures the movement of chromosomes after 15 minutes in low serum was inhibited. When high serum was restored to the serum starved cultures chromosome repositioning was only evident after 24-36 hours that coincided with a return to a proliferating distribution of nuclear myosin 1β