N-Gram in Swin Transformers for Efficient Lightweight Image Super-Resolution

While some studies have proven that Swin Transformer (SwinT) with window self-attention (WSA) is suitable for single image super-resolution (SR), SwinT ignores the broad regions for reconstructing high-resolution images due to window and shift size. In addition, many deep learning SR methods suffer from intensive computations. To address these problems, we introduce the N-Gram context to the image domain for the first time in history. We define N-Gram as neighboring local windows in SwinT, which differs from text analysis that views N-Gram as consecutive characters or words. N-Grams interact with each other by sliding-WSA, expanding the regions seen to restore degraded pixels. Using the N-Gram context, we propose NGswin, an efficient SR network with SCDP bottleneck taking all outputs of the hierarchical encoder. Experimental results show that NGswin achieves competitive performance while keeping an efficient structure, compared with previous leading methods. Moreover, we also improve other SwinT-based SR methods with the N-Gram context, thereby building an enhanced model: SwinIR-NG. Our improved SwinIR-NG outperforms the current best lightweight SR approaches and establishes state-of-the-art results. Codes will be available soon.Comment: 8 pages (main content) + 14 pages (supplementary content

Undaria pinnatifida sporophyll으로부터 fucose 함유물의 추출과 Bifidobacterium longum RD47을 이용한 푸코실 올리고당의 합성

학위논문 (석사)-- 서울대학교 대학원 : 식품영양학과, 2015. 8. 지근억.Human milk oligosaccharides (HMOs) are mostly fucosylated at their non-reducing termini. HMOs are known to function as a prebiotic for bifidobacteria. L-fucose is major component of HMOs but very costly. Fucoidan is a group of marine sulfated polysaccharide of the cell-wall matrix of brown algae, containing large proportions of L-fucose. In this research, L-fucose containing monosaccharides (FCMs) were obtained from fucoidan. For the experiment, fucoidan was extracted from U. pinnatifida sporophyll using 0.03 M HCl. Crude fucoidan was purified by ion-exchange chromatography and hydrolyzed to obtain FCMs. The analysis of monosaccharides composition was performed by Bio-LC. FCMs were applied to gel permeation column and used as a substrate to synthesize FO using the crude enzyme extracts from Bifidobacterium longum RD47. The synthesized FO was detected by thin layer chromatography. In the application aspect, the FO may provide a new constituent for cost-effective prebiotic food ingredient.Contents Abstract .......................................................................................................... ⅰ Contents ......................................................................................................... ⅲ List of Figures .............................................................................................. ⅴ List of Tables ................................................................................................ ⅵ List of abbreviations .................................................................................... ⅶ 1. Introduction .............................................................................................. 1 2. Material and Methods ...................................................................... 4 2.1. Materials .................................................................................... 4 2.1.1. Source of extraction ......................................................... 4 2.1.2. Microorganism strains and culture condition ................. 4 2.1.3. Chemicals and reagents ................................................... 4 2.2. Extraction and purification of fucoidan ................................... 5 2.3. Preparation of the purified fucoidan hydrolysate ................... 7 2.4. Preparation of FCMs ................................................................. 8 2.5. Chemical Anlaysis ..................................................................... 9 2.5.1. Analysis by TLC ............................................................... 9 2.5.2. Determination of monosaccharide composition by Bio- LC ...................................................................................... 9 2.5.3. Determination of anion composition by anion chromatography ............................................................. 12 2.6. Synthesis of fucosylated oligosaccharide using Bifidobacterium longum RD47 ...................................... 14 2.6.1. Preparation of crude enzyme extracts ......................... 14 2.6.2. Determination of β-galactosidase activity in crude cell extracts ........................................................................... 14 2.6.3. Synthesis of fucosylated oligosaccharide using FCMs ............................................................................... 15 3. Results and discussion.......................................................................... 16 3.1. Yield of crude fucoidan from U. pinnatifida sporophyll ........ 16 3.2. Bio-LC analysis of the purified fucoidan hydrolysate ........ 17 3.3. Anion analysis of the purified fucoidan hydrolysate ......... 19 3.4. Determination of FCMs .......................................................... 21 3.5. Determination of oligosaccharides synthesized by crude enzyme extracts from B. longum RD47 .............................. 23 4. Conclusion ............................................................................................. 28 References ................................................................................................ 29 Abstract in Korean .................................................................................. 34Maste

Essays on Asset Pricing and Financial Stability

My two-essay dissertation revolves around understanding the financial crisis of 2008. First I focus on the repo market, a major funding source of the shadow banking system, and show the repo market can create and amplify the fragility of the system. Then I investigate a broader economy with heterogeneous agents and demonstrate how the dynamics of equilibrium asset prices and wealth distributions are determined. In Essay 1, I develop a dynamic model of collateral circulation in a repo market, where a continuum of institutions borrow from and lend to one another against illiquid collateral. The model emphasizes an important tradeoff. On one hand, easier collateral circulation makes repos liquid and increases steady state investment through several multiplier effects, improving economic efficiency. On the other hand, it can harm financial stability because less capital is sitting on the sidelines waiting for investment opportunities. This fragility is further exacerbated by the endogenous repo spread through a positive feedback loop, and can result in an inefficient repo run. The model is relevant for understanding the repo markets during the financial crisis of 2008. In Essay 2, I study the dynamics of the wealth distribution and asset prices in a general equilibrium model. Agents face heterogeneous portfolio constraints that limit the shares of risky investments relative to wealth. The setup is motivated by empirical evidence that many households do not participate in the stock market and portfolio shares are heterogeneous and persistent conditional on stock market participation. There are two main results. First, one state variable can summarize the wealth distribution regardless of the number of types of agents. Second, when the economy is bad, it becomes more sensitive to additional negative shocks, meaning that not only magnitudes of the shocks but also their frequency matters

Motion detection algorithm using wavelet transform

This thesis presents an algorithm that estimates motion in image sequence using wavelet transform. The motion detection is performed under unfavorable conditions of background movement, change of brightness, and noise. The algorithm is tolerant to brightness changes, noise, and small movement in the background. The false alarm rate of motion detection is reduced as compared to standard techniques. Using wavelet transform is numerically efficient and the storage requirements are significantly reduced. Also, a more accurate motion detection is achieved. Tests performed on real images show the effectiveness of this algorithm. Practical results of motion detection are presented

Plasmon thermal conductivity of thin Au and Ag films

We investigated the thermal conductivity of surface plasmon polaritons (SPPs) propagating along thin Au and Ag films on a SiO$_2$ substrate with a Ti adhesive layer. To determine the propagation length and skin depth of SPPs along Au and Ag thin films, we numerically solved the dispersion relation while considering the size effect of the permittivity of metal. Additionally, we derived the spatial distribution of SPPs along the film thickness to analyze the effect of the Ti adhesive layer on the plasmon thermal conductivity of Au and Ag thin films. Our theoretical predictions revealed a decrease of approximately 30\% in plasmon thermal conductivity when considering the size effect of the permittivity of thin metal films. Furthermore, this causes the film thickness at which maximum thermal conductivity occurs to increase by about 30\%. Taking these factors into account, we calculated the optimal thickness of Au and Ag films, along with Ti adhesive layers, on SiO$_2$ substrates to be approximately 20 nm. By fabricating a sample with the optimal thickness of Au and Ag films, we experimentally demonstrated that the plasmon thermal conductivity of Au and Ag films can be as high as about 20\% of their electron contribution. This research will broaden the thermal design applications of ballistic thermal transport by SPPs propagating along thin metal coatings in microelectronics.Comment: 5 figure

Encoding Speaker-Specific Latent Speech Feature for Speech Synthesis

In this work, we propose a novel method for modeling numerous speakers, which enables expressing the overall characteristics of speakers in detail like a trained multi-speaker model without additional training on the target speaker's dataset. Although various works with similar purposes have been actively studied, their performance has not yet reached that of trained multi-speaker models due to their fundamental limitations. To overcome previous limitations, we propose effective methods for feature learning and representing target speakers' speech characteristics by discretizing the features and conditioning them to a speech synthesis model. Our method obtained a significantly higher similarity mean opinion score (SMOS) in subjective similarity evaluation than seen speakers of a best-performing multi-speaker model, even with unseen speakers. The proposed method also outperforms a zero-shot method by significant margins. Furthermore, our method shows remarkable performance in generating new artificial speakers. In addition, we demonstrate that the encoded latent features are sufficiently informative to reconstruct an original speaker's speech completely. It implies that our method can be used as a general methodology to encode and reconstruct speakers' characteristics in various tasks

Switching of Perpendicularly Polarized Nanomagnets with Spin Orbit Torque without an External Magnetic Field by Engineering a Tilted Anisotropy

Spin orbit torque (SOT) provides an efficient way of generating spin current that promises to significantly reduce the current required for switching nanomagnets. However, an in-plane current generated SOT cannot deterministically switch a perpendicularly polarized magnet due to symmetry reasons. On the other hand, perpendicularly polarized magnets are preferred over in-plane magnets for high-density data storage applications due to their significantly larger thermal stability in ultra-scaled dimensions. Here we show that it is possible switch a perpendicularly polarized magnet by SOT without needing an external magnetic field. This is accomplished by engineering an anisotropy in the magnets such that the magnetic easy axis slightly tilts away from the film-normal. Such a tilted anisotropy breaks the symmetry of the problem and makes it possible to switch the magnet deterministically. Using a simple Ta/CoFeB/MgO/Ta heterostructure, we demonstrate reversible switching of the magnetization by reversing the polarity of the applied current. This demonstration presents a new approach for controlling nanomagnets with spin orbit torque

Multifunctional TPP-PEG-biotin self-assembled nanoparticle drug delivery-based combination therapeutic approach for co-targeting of GRP78 and lysosome

Abstract Background In this study, a multifunctional tetraphenylporphyrin (TPP) conjugated polyethylene glycol with biotin (TPP-PEG-biotin) as a photo-dynamic therapy (PDT) material encapsulating a ruthenium complex 1 (Ru-1) was fabricated as self-assembled nanoparticle (Ru-1@TPP-PEG-biotin SAN) to co-target glucose-regulated protein 78 (GRP78) and the lysosome as a new anti-cancer therapeutic strategy. Results The MTT assay results reveals the enhanced anticancer activity of the Ru-1@TPP-PEG-biotin SANs due to the co-targeting of the GRP78 and lysosome. The Ru-1@TPP-PEG-biotin reduced level of GRP78 and lysosomal ceramide that contributed to the stability of the lysosomal membrane. The endoplasmic reticulum (ER) stress concomitant with the inhibition of GRP78 was clearly monitored by the phosphorylation of protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), and inositol-requiring enzyme 1 α (IRE1α) kinases to indicate the activation of the unfolded protein response (UPR) signaling using immunofluorescence assay. On the other hand, the degradation of the lysosome was observed through PDT action by the Ru-1@TPP-PEG-biotin SAN treatment. This was confirmed by the co-localization assay showing the disappearance of cathepsin D and lysosomal-associated membrane protein 1 (LAMP1) in the lysosome. Conclusions Considering lysosome-mediated autophagy is an effective cancer cell survival mechanism, the degradation of the lysosome along with GRP78 inhibition by the Ru-1@TPP-PEG-biotin SAN combination therapy is suggested as a new co-targeting cancer treatment