124 research outputs found
Robustness and generalization guarantees for statistical learning of generative models
Get PDFWe apply tools from the classical statistical learning theory to analyze theoretical properties of modern machine learning problems that are typically phrased in the context of generative models. By combining standard methods based on the theory of empirical processes with ideas from optimal transport and signal recovery, we formally address the generalization and robustness guarantees for the existing and newly suggested algorithms. More specifically, we consider the following three problems: First, we tackle the problem of domain adaptation, where the training data and the test data are drawn from two distributions that are related but not identical. We devise an empirical risk minimization algorithm based on local worst-case risks, and provide generalization and excess risk guarantees of the learned hypothesis, that are robust to drifts in generative models. Second, we consider the learning of coding schemes, where the goal is to minimize the reconstruction risk of the original signal. It turns out that the task can be viewed as approximating the signal-generating distributions by pushforwards of arbitrary distributions via reconstruction maps. We provide learning guarantees based on the notions of optimal transport and classic statistical learning, using reconstruction errors as hypotheses. Third, we propose a framework of assessing representation learning algorithms by evaluating their estimation capabilities of the representation generating the signal. Using polyhedral estimates from the signal recovery literature, we investigate the provably near-optimal guarantees of the topic model.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-05-01The student, Jaeho Lee, accepted the attached license on 2019-01-15 at 12:21.The student, Jaeho Lee, submitted this Dissertation for approval on 2019-01-15 at 12:28.This Dissertation was approved for publication on 2019-01-15 at 14:39.DSpace SAF Submission Ingestion Package generated from Vireo submission #13358 on 2019-08-22 at 15:03:55Made available in DSpace on 2019-08-23T20:28:03Z (GMT). No. of bitstreams: 3
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Previous issue date: 2019-01-15Embargo set by: Seth Robbins for item 112074
Lift date: 2021-08-23T20:28:11Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112074
Lift date: 2021-08-23T20:29:33Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112074
Lift date: 2021-08-23T20:36:18Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 112074 on 2021-08-24T09:15:10Z
Ag Electrode Strain Sensor Fabrication Using Laser Direct Writing Process
No full textAs several innovative technologies for flexible electric devices are being realized, demand for in-situ strain monitoring for flexible electric devices is being emphasized. Because flexible devices are commonly influenced by substrate strain, suitable strain sensors for flexible devices are essential for the sophisticated maneuvering of flexible devices. In this study, a flexible strain sensor based on an Ag electrode is prepared on a polyimide substrate using the LDW (laser direct writing) process. In this process, first, the Ag nanoparticles are coated on the substrate and selectively sintered using a focused laser. Because of the advantages of the LDW process (such as being mask-less, using low temperatures, and having non-vacuum characteristics), the entire fabrication process has been dramatically simplified; as a final outcome, a highly reliable strain sensor has been fabricated. Using this strain sensor, various strain conditions that arise from different bending radii can be detected by measuring real-time electrical signals.N
Monolithic digital patterning of polydimethylsiloxane with successive laser pyrolysis
No full text© 2020, The Author(s), under exclusive licence to Springer Nature Limited.The patterning of polydimethylsiloxane (PDMS) into complex two-dimensional (2D) or 3D shapes is a crucial step for diverse applications based on soft lithography. Nevertheless, mould replication that incorporates time-consuming and costly photolithography processes still remains the dominant technology in the field. Here we developed monolithic quasi-3D digital patterning of PDMS using laser pyrolysis. In contrast with conventional burning or laser ablation of transparent PDMS, which yields poor surface properties, our successive laser pyrolysis technique converts PDMS into easily removable silicon carbide via consecutive photothermal pyrolysis guided by a continuous-wave laser. We obtained high-quality 2D or 3D PDMS structures with complex patterning starting from a PDMS monolith in a remarkably low prototyping time (less than one hour). Moreover, we developed distinct microfluidic devices with elaborated channel architectures and a customizable organ-on-a-chip device using this approach, which showcases the potential of the successive laser pyrolysis technique for the fabrication of devices for several technological applications.N
노트 : Korea Development Institute, P.O. Box 113, Cheongnyang, Seoul 130-012, Korea. (T)82-2-958-4204, (email) [email protected]. This paper is the outgrowth of the paper prepared for the KDI 33rd Anniversary Conference on Industrial Dynamism and Comptitiveness in the East Asian Economies. The author is grateful to Chunsik Woo, Chin-Hee Hahn, Dongseok Kim, Jaeho Lee and Joonghae Suh for their constructive comments and encouragement, and appreciate participants of the conference for their comments. In particular, Dongseok Kim and Jaeho Lee provided invaluable advice on productivity and trade performance respectively. Assistance from Jungmi Kim and Kwangsung Kim is greatly appreciated
High-temperature, thin, flexible and transparent Ni-based heaters patterned by laser-induced reductive sintering on colorless polyimide
No full textThis study reports a novel method for the fabrication of a high-performance, flexible and transparent heater (TH) comprising imperceptible nickel (Ni) micropatterns on a colorless polyimide (cPI) substrate. The specially developed laser digital patterning (LDP) process, which utilizes laser-thermal degradation of organic surfactants generating reducing agent, enables a fast, affordable, and reliable way to form Ni-grid/cPI structures with a low sheet resistance (26.3 omega sq(-1)) and a high transmittance (87.3% at 550 nm). Thanks to the thermal stability of Ni and cPI, together with the low sheet resistance, the Ni/cPI TH exhibits stable performance even at the highest heating temperature ever reported for flexible TH (310 degrees C at 11 V). As a consequence, the proposed scheme realizes an advanced process for the fabrication of chemically and mechanically stable, lightweight (4.1 mg cm(-1)), high-performance, and flexible TH.N
Conditional <i>KO</i> of <i>Wwox via BK5-Cre</i> and <i>MMTV-Cre</i>.
No full text<p>(A–F) Immunostaining of formalin-fixed histological sections of mammary glands from each model of deletion reveals strong cytoplasmic Wwox staining in <i>WT</i> samples and significant loss of Wwox protein expression in <i>KO</i> animals. (A) 8 week virgin <i>BK5 Wwox WT</i>, (B) 8 week virgin <i>BK5 Wwox KO</i>, (C) P18.5 days <i>BK5 Wwox WT</i>, (D) P18.5 days <i>BK5 Wwox KO</i>, (E) 24 week virgin <i>MMTV Wwox WT</i>, (F) 24 week <i>MMTV Wwox KO</i>. Rabbit anti-Wwox <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036618#pone.0036618-Bednarek2" target="_blank">[14]</a> antibody was used at a 1∶50 dilution and counterstained with hematoxylin. All images were obtained at the same 10× magnification.</p
Human Circulatory/Respiratory-Inspired Comprehensive Air Purification System
No full textThe circulatory and respiratory systems in humans are marvels of biological engineering that exhibit competence in maintaining homeostasis. These systems not only shield the organism from external contaminants but also orchestrate the vital gases via the bloodstream to sustain cellular respiration and metabolic processes across diverse tissues. It is noticed that spaces inhabited encounter challenges akin to those of the human body: protecting the indoor air from external pollutants while removing anthropogenic byproducts like carbon dioxide (CO2), particulate matters (PM), and volatile organic compounds (VOCs) tooutside. A biomimetic approach, composed of a microbubble-based gas exchanger and circulating liquid inspired by alveoli, capillary beds, and bloodstream of the human circulatory/respiratory system, offer an innovative solution for comprehensive air purification of hermetic spaces. Circulatory/respiratory-inspired air purification system (CAPS) ensure both continuous removal of PM and exchange of gas species between indoor and outdoor environments to maintain homeostasis. The effectiveness of this system is also supported by animal behavior experiments with and without CAPS, showing an effect of reducing CO2 concentration by 30% and increasing mice locomotor activity by 53%. CAPS is expected to evolve into robust and comprehensive air purification schemes through the networked integration of plural internal and external environments. A circulatory/respiratory-inspired air purification system (CAPS) is reported, a novel bioinspired approach that integrates microbubble-based gas exchange and circulating liquid (water) mechanisms akin to alveoli, capillary beds, and the bloodstream. By incorporating waste removal, CAPS ensures continuous particulate matter removal and gas exchange between indoor and outdoor spaces, with the potential for networked integration across various internal and external environments. imageY
<i>Wwox-KO BK5-Cre</i> transgenic mice model gene expression profile study.
No full text<p>(A) Heatmap of the differentially expressed genes between <i>Wwox WT vs. Wwox KO</i> mammary gland epithelial organoid samples (p<0.01; 2 Fold changes). Color scale at bottom of picture is used to represent expression level: low expression is represented by green, and high expression is represented by red. (B) Expression graph of the 913 deregulated probes (136 probes down-modulated and 777 up-modulated) among <i>Wwox WT</i> and <i>Wwox KO</i> mammary epithelial organoid samples. (C) Scatterplot graph showing the representative clusters, after redundancy reduction of the statistical significant GO terms (p<0.025) enriched in the deregulated gene list, in a two dimensional space related to GO terms' semantic similarities. Bubble color indicates the p-value of GO terms (expressed as Log10 p-value) and bubble size indicates the frequency of the GO term in the underlying GOA database (bubbles of more general terms are larger).</p
<i>Wnt5a</i> expression increases in <i>BK5 Wwox KO</i> mammary epithelium.
No full text<p>Semi-quantitative RT-PCR was performed on cDNA synthesized from RNA obtained from mammary epithelial organoids (3 different animals per group) as discussed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036618#s4" target="_blank">Materials and Methods</a>. Lanes from left to right are: (lanes 1–3) 8 week virgin <i>Wwox WT</i>, (lanes 4–6) P18.5 <i>Wwox WT</i>, (lanes 7–9) 8 week virgin <i>Wwox KO</i>, and (lanes 10–12) P18.5 <i>Wwox KO</i>. <i>Wwox</i> expression is shown in the middle panel as further verification of <i>Wwox</i> ablation. <i>Gapdh</i> expression is shown as a normalization control. Each PCR reaction was performed at 24, 26, 28 and 32 cycles to ensure that reaction was in linear range. Results shown at 24 cycles.</p
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