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The etch rate uniformity in photoresist etching was monitored using multi-channel optical emission spectroscopy (OES) and a spatially resolved etch rate model incorporating radical and ion etching characteristics. The F radical densities at various locations were estimated using 8-channel OES and applied to a radical-spontaneous etch rate model to examine the impact of radicals on the etch rate. The ion fluxes were measured using a scanning floating harmonic probe for an ion-enhanced etch rate model to investigate the effect of ions on the etch rate. A combined etch rate model was proposed to explain the effects on both radical and ion etching characteristics, and the etch rates and etch rate uniformities predicted by the model were quantitatively compared with the measured values. The calculated R-squared score (R2) and the mean absolute percentage error (MAPE) of the etch rates predicted by the model were 0.99 and 1.3%, respectively. The etch rate uniformities predicted by the model showed good accuracy with R2 of 0.99 and MAPE of 12.0% compared to the measured values, and the combined etch rate model also successfully predicted the distribution of the etch rate. This study demonstrates that multi-channel OES and the developed model can quantitatively predict the etch rate distribution of plasma etching processes. [ABSTRACT FROM AUTHOR]

Recently, the concept of a circular economy for carbon neutrality is emerging. In particular, waste plastics are one of the key wastes, and efforts are being made to recycle them as energy rather than dispose of them. Accordingly, the technology of producing and utilizing pyrolysis oil from waste plastics attracts attention. As it is an early stage of technology development, however, there are not many demonstrations and papers that analyze the technology broadly. The goal of this study is to propose building a circular economy on a university campus through waste plastic pyrolysis oil technology. To show its feasibility, waste plastic pyrolysis oil technology is analyzed comprehensively from economic, environmental, and policy perspectives using the scenario analysis technique on the university campus level. A methodology of the scenario analysis technique enables predicting the uncertainties. Since plastic pyrolysis oil technologies and carbon neutrality are accompanied by many uncertainties, this technique is expected to be an appropriate methodology for this study. First, the amount of pyrolysis oil production from waste plastics from the campus is estimated. Then, the cost and carbon emissions from waste plastics are estimated if the pyrolysis oil technology is used instead of the traditional waste disposal process. As a result, the total economic profits of up to 425,484,022 won/year (354,570.01 $/year) are expected when a circular economy is built using waste plastic pyrolysis oil. In addition, it is also confirmed that greenhouse gas (GHG) emissions can be reduced by up to 840,891 kgCO2eq/year. The waste plastic pyrolysis oil satisfies Korea's gas pollutant standards and is consistent with the GHG reduction policy. It can be concluded that building a circular economy at the university campus level using waste plastic pyrolysis oil technology is suitable from economic, environmental, and policy perspectives. [ABSTRACT FROM AUTHOR]

In this paper, we prove two rigidity results of hypersurfaces in n-dimensional weighted Riemannian manifolds with weighted scalar curvature bounded from below. Firstly, we establish a splitting theorem for the n-dimensional weighted Riemannian manifold via a weighted area-minimizing hypersurface. Secondly, we observe the topological invariance of the weighted stable hypersurface when the ambient weighted scalar curvature is bounded from below by a positive constant. In particular, we derive a non-existence result for a weighted stable hypersurface. [ABSTRACT FROM AUTHOR]

Background: Alarmins S100A8 and S100A9 are recognized as hallmarks of severe COVID-19 and are primarily produced in myeloid cells, such as monocytes and neutrophils. As single-cell RNA-sequencing (scRNA-seq) data from patients with COVID-19 revealed the expression of S100A8/A9 in lymphoid cells in patients with severe COVID-19. Objective: We investigated the characteristics of lymphoid cells expressing S100A8/A9 in COVID-19 patients. Methods: Publicly available scRNA-seq data from patients with mild (N = 12) or severe (N = 7) COVID-19 were reanalyzed. The data were further divided into the following two groups based on the time of sample collection (from infection-onset): within 6 days (early phase) and after 6 days (late phase). Differential expression and gene set enrichment analyses were performed between S100A8/A9High and S100A8/A9Low lymphoid cells. Finally, cell-cell interaction analysis was performed to investigate the role of lymphoid cells expressing high levels of S100A8/A9 in COVID-19. Results: S100A8/A9 overexpression was observed in lymphoid cells, including B cells, T cells, and NK cells, in patients with severe COVID-19 (compared to patients with mild COVID-19). Cells exhibiting strong interferon/cytokine responses were found to be associated with the severity of COVID-19. Furthermore, differences in S100A8/A9-TLR4/RAGE interactions were confirmed between patients with severe and mild disease. Conclusions: Lymphoid cells overexpressing S100A8/A9 contribute to the dysregulation of the innate immune response in patients with severe COVID-19, specifically during the early phase of infection. This study fosters a better understanding of the hyper-induction of pro-inflammatory cytokine expression and the generation of a cytokine storm in response to COVID-19 infection. [ABSTRACT FROM AUTHOR]

Recently, water scarcity has become a serious social problem caused by global climate change. In agricultural water usage, subsurface irrigation techniques can be an alternative method to save water and improve the productivity and quality of crops. The technique supplies water by burying an irrigation hose 30 cm underground rather than placing it on the ground (topsoil), effectively preventing evaporation loss at the soil surface. In this study, we numerically calculated the pressure drop using a dripper installed inside an underground irrigation hose developed in Korea. The pumping load of the domestic product was evaluated in terms of momentum loss and compared with the most widely used Netafim products. The lower the pressure drop in the dripper, the higher the performance of the irrigation system in terms of stable water supply. Using computational fluid dynamics and experiments, we provide a meaningful evaluation of the domestic product in the irrigation system. [ABSTRACT FROM AUTHOR]

Asthma and chronic obstructive pulmonary disease (COPD) are two distinct diseases that are associated with chronic inflammation. They share common features in terms of their advanced stages and genetic factors. This study aimed to identify novel genes underlying both asthma and COPD using genome-wide association study (GWAS) to differentiate between the two diseases. We performed a GWAS of asthma and COPD in 7828 Koreans from three hospitals. In addition, we investigated genetic correlations. The UK Biobank dataset was used for the replication studies. We found that rs2961757, located near neuromedin U receptor 2 (NMUR2) on chromosome 5, was genome-wide significant ( β Asthma - COPD = 0.44, P-valueAsthma-COPD = 3.41 × 10−8), and significant results were replicated with the UK Biobank data ( β Asthma - COPD = 0.04, P-valueAsthma-COPD = 0.0431). A positive genetic correlation was observed between asthma and COPD (39.8% in the Korean dataset and 49.8% in the UK Biobank dataset). In this study, 40–45% of the genetic effects were common to asthma and COPD. Moreover, NMUR2 increases the risk of asthma development and suppresses COPD development. This indicates that NMUR2 allows for better differentiation of both diseases, which can facilitate tailored medical therapy. [ABSTRACT FROM AUTHOR]

A subsurface drip irrigation system delivers water and nutrients directly to the plant root zone; other conventional nozzles-type or sprinklers-type irrigation are not used, and water-saving can reach 42–78%. In order to achieve this impact effectively, the drip irrigation requires a constant water supply under variations in pressure, which is so-called pressure compensating (PC) performance. The pressure compensating feature can be obtained by physical interaction between water flow and deformable silicone rubber in the PC dripper. In addition, pressure condition to ensure uniform water flow as a tresholding point also should be well designed, but it is generally have relied on the empiricial optimization. Here, we applied computational fluid dynamics to investigate water flow features in terms of flow rate and pressure drop of a conventional PC dripper. To understand the quantitative effects of changes in design parameters, we explored the fluid-structure interaction scheme in the CFD analysis between water flow and silicone rubber deformation. In this study, it is found that the marginal space for the silicone rubber deformation determined the threshold pressure condition; the friction condition of the tortuous channel of the dripper controlled the flow rate. This parametric study gave the logical insight to design new drip emitter with well-controlled and improved performance. [ABSTRACT FROM AUTHOR]

In this paper, we extend compactness theorems of Cheeger, Gromov, Taylor, and Sprouse to the Bakry–Émery Ricci tensor and generalized quasi-Einstein tensors. Our results generalize previous results obtained by Yun and Wan. [ABSTRACT FROM AUTHOR]

Reputation is a powerful mechanism to enforce cooperation among unrelated individuals through indirect reciprocity, but it suffers from disagreement originating from private assessment, noise, and incomplete information. In this work, we investigate stability of cooperation in the donation game by regarding each player's reputation and behaviour as continuous variables. Through perturbative calculation, we derive a condition that a social norm should satisfy to give penalties to its close variants, provided that everyone initially cooperates with a good reputation, and this result is supported by numerical simulation. A crucial factor of the condition is whether a well-reputed player's donation to an ill-reputed co-player is appreciated by other members of the society, and the condition can be reduced to a threshold for the benefit-cost ratio of cooperation which depends on the reputational sensitivity to a donor's behaviour as well as on the behavioural sensitivity to a recipient's reputation. Our continuum formulation suggests how indirect reciprocity can work beyond the dichotomy between good and bad even in the presence of inhomogeneity, noise, and incomplete information. [ABSTRACT FROM AUTHOR]

Medical costs have recently increased in South Korea due to the rising rate of asthma. Primary clinics serve an important role in asthma management, as they are the first stop for patients presenting with symptoms. The Health Insurance Review and Assessment Service (HIRA) in South Korea has assessed asthma-management quality since 2013, but studies are lacking on whether these assessments have been performed properly and contribute toward reducing asthma exacerbations. Therefore, we investigated whether the HIRA's quality assessments have decreased asthma exacerbations using national health insurance claims data from 2013 to 2017 of 83,375 primary-clinic and 15,931 tertiary-hospital patients with asthma. These patients were classified into four groups based on disease severity according to the monthly prescribed amount of asthma medication using K-means clustering. The associations between HIRA assessments and asthma exacerbation were analyzed using a generalized estimating equation. Our results showed that exacerbation odds gradually decreased as the HIRA assessments progressed, especially in the mild-severity group, and that exacerbation risk among patients with asthma decreased in the order of assessment grades: "Unsatisfactory," "Satisfactory," and "Tertiary." Therefore, we may conclude that asthma exacerbations may decrease with high quality asthma management; appropriate quality assessment could be helpful in reducing asthma exacerbations. [ABSTRACT FROM AUTHOR]

Overfitting is one of the most challenging problems in deep neural networks with a large number of trainable parameters. To prevent networks from overfitting, the dropout method, which is a strong regularization technique, has been widely used in fully-connected neural networks. In several state-of-the-art convolutional neural network architectures for object classification, however, dropout was partially or not even applied since its accuracy gain was relatively insignificant in most cases. Also, the batch normalization technique reduced the need for the dropout method because of its regularization effect. In this paper, we show that conventional element-wise dropout can be ineffective for convolutional layers. We found that dropout between channels in the CNNs can be functionally similar to dropout in the FCNNs, and spatial dropout can be an effective way to take advantage of the dropout technique for regularizing. To prove our points, we conducted several experiments using the CIFAR-10 and CIFAR-100 databases. For comparison, we only replaced the dropout layers with spatial dropout layers and kept all other hyperparameters and methods intact. DenseNet-BC with spatial dropout showed promising results (3.32% error rates with CIFAR-10, 3.0 M parameters) compared to other existing competitive methods. [ABSTRACT FROM AUTHOR]

Background: There are many research studies have estimated the heritability of phenotypic traits, but few have considered longitudinal changes in several phenotypic traits together. Objective: To evaluate the progressive effect of single nucleotide polymorphisms (SNPs) on prominent health-related phenotypic traits by determining SNP-based heritability ( h snp 2 ) using longitudinal data. Methods: Sixteen phenotypic traits associated with major health indices were observed biennially for 6843 individuals with 10-year follow-up in a Korean community-based cohort. Average SNP heritability and longitudinal changes in the total period were estimated using a two-stage model. Average and periodic differences for each subject were considered responses to estimate SNP heritability. Furthermore, a genome-wide association study (GWAS) was performed for significant SNPs. Results: Each SNP heritability for the phenotypic mean of all sixteen traits through 6 periods (baseline and five follow-ups) were significant. Gradually, the forced vital capacity in one second (FEV1) reflected the only significant SNP heritability among longitudinal changes at a false discovery rate (FDR)-adjusted 0.05 significance level ( h snp 2 = 0.171 , FDR = 0.0012). On estimating chromosomal heritability, chromosome 2 displayed the highest heritability upon periodic changes in FEV1. SNPs including rs2272402 and rs7209788 displayed a genome-wide significant association with longitudinal changes in FEV1 (P = 1.22 × 10−8 for rs2272402 and P = 3.36 × 10−7 for rs7209788). De novo variants including rs4922117 (near LPL, P = 2.13 × 10−15) of log-transformed high-density lipoprotein (HDL) ratios and rs2335418 (near HMGCR, P = 3.2 × 10−9) of low-density lipoprotein were detected on GWAS. Conclusion: Significant genetic effects on longitudinal changes in FEV1 among the middle-aged general population and chromosome 2 account for most of the genetic variance. [ABSTRACT FROM AUTHOR]

The neural substrates related to periodic leg movements during sleep (PLMS) remain uncertain, and the specific brain regions involved in PLMS have not been evaluated. We investigated the brain regions associated with PLMS and their severity using the electroencephalographic (EEG) source localization method. Polysomnographic data, including electromyographic, electrocardiographic, and 19-channel EEG signals, of 15 patients with restless legs syndrome were analyzed. We first identified the source locations of delta-band (2–4 Hz) spectral power prior to the onset of PLMS using a standardized low-resolution brain electromagnetic tomography method. Next, correlation analysis was conducted between current densities and PLMS index. Delta power initially and most prominently increased before leg movement (LM) onset in the PLMS series. Sources of delta power at −4~−3 seconds were located in the right pericentral, bilateral dorsolateral prefrontal, and cingulate regions. PLMS index was correlated with current densities at the right inferior parietal, temporoparietal junction, and middle frontal regions. In conclusion, our results suggest that the brain regions activated before periodic LM onset or associated with their severity are the large-scale motor network and provide insight into the cortical contribution of PLMS pathomechanism. [ABSTRACT FROM AUTHOR]

As a result of advances in sequencing technology, the role of gut microbiota in the mechanism of type-2 diabetes mellitus (T2DM) has been revealed. Studies showing wide distribution of microbiome throughout the human body, even in the blood, have motivated the investigation of the dynamics in gut microbiota across the humans. Particularly, extracellular vesicles (EVs), lipid bilayer structures secreted from the gut microbiota, have recently come into the spotlight because gut microbe-derived EVs affect glucose metabolism by inducing insulin resistance. Recently, intestine hyper-permeability linked to T2DM has also been associated with the interaction between gut microbes and leaky gut epithelium, which increases the uptake of macromolecules like lipopolysaccharide from the membranes of microbes leading to chronic inflammation. In this article, we firstly investigate the co-occurrence of stool microbes and microbe-derived EVs across serum and urine in human subjects (N = 284), showing the dynamics and stability of gut derived EVs. Stool EVs are intermediate, while the bacterial composition in both urine and serum EVs is distinct from the stool microbiome. The co-occurrence of microbes was compared between patients with T2DM (N = 29) and matched in healthy subjects (N = 145). Our results showed significantly higher correlations in patients with T2DM compared to healthy subjects across stool, serum, and urine, which could be interpreted as the dysfunction of intestinal permeability in T2DM. Therefore, the significant correlation of EVs might give insight into the pathophysiological mechanisms of T2DM, as well as the role of EVs as a biomarker in the intestinal permeability of T2DM. [ABSTRACT FROM AUTHOR]

We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs. [ABSTRACT FROM AUTHOR]

In this paper, we address the problem of boundary image matching that supports symmetric invariance. Supporting the symmetric invariance is an important factor to provide more intuitive and more correct results in boundary image matching. Previous boundary image matching methods, however, deal with mainly image rotations without consideration of symmetric transformations. In this paper, we propose a time-series-based boundary image matching that supports the symmetric invariance as well as the previous rotation invariance. For this, we first formally define the concept of a boundary time-series and its symmetric time-series. We then present a novel notion of symmetric-rotation property that the rotation-invariant matching result is always the same for all possible symmetric angles. We next discuss how to efficiently extract a symmetric time-series from an image boundary by presenting the domain independent property that both time-series domain and image domain methods produce the same symmetric time-series. Experimental results show that the proposed symmetric-invariant matching provides the more intuitive result compared with the previous rotation-invariant matching. To our best knowledge, this is the first attempt that solves the symmetric-invariant boundary matching problem in the simple time-series domain rather than in the complex image domain. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method of elaborating and detecting brain tumor from MRI suitable for information sharing via the internet for a healthcare provider. This method allows for reducing image sizes without reducing the information content of the images in terms of detecting tumors. The proposed method involves first clarifying the brain tumor area using a modified K-means clustering method and initial segmentation using mean shift segmentation. Then a threshold setting is used to convert the gray scale image and remove noise by applying an erode operation. Finally, the brain tumors in the images are detected using a watershed algorithm. The proposed method was compared with two well-known methods namely the conventional K-mean clustering and Fuzzy C Means (FCM) clustering. We verified the precision and the objectivity of our proposed method. The average precision and recall for our proposed method were excellent with values of 0.914052 and 0.995641, respectively. Our method detected more brain tumors than the conventional K-means clustering and FCM clustering methods and was able to provide for an efficient image data processing with reduced file sizes. [ABSTRACT FROM AUTHOR]

This paper presents a new normalized cut algorithm using a bilateral filter for fast transmission in Intelligent Traffic Control System (ITS) based on ubiquitous technology. The algorithm employs a bilateral filter to produce a binarized image used to extract outlines with the Canny Edge algorithm then applies dilation with improved normalized cut to extract objects from the image. The result of the proposed method was compared to the results of the normalized cut algorithm using the K-Means clustering technique and showed that the new algorithm reduced the processing time for extracting objects, causing much faster data transmission on uTSN. [ABSTRACT FROM AUTHOR]

Cascade cycle is widely applied to heat pumps operating at low ambient temperature to overcome problems such as low heating capacity and Coefficient of performance (COP) deterioration A number of researches have been conducted on cascade cycle heat pumps, but most of those studies were focused on system optimization to determine optimal intermediate temperature in air-to-water heat pumps. However, experimental optimization in regard to air and water heating simultaneously using a cascade cycle has been an understudied area. Therefore, we focused on experimental analysis for a cascade system with Variable refrigerant flow (VRF) heat pumps. Experiments were conducted under a variety of operating conditions, such as ambient and water inlet temperature. COP increased up to 16% when water inlet temperature decreased. COP of VRF heat pumps with cascade cycle is three-times higher compared with conventional boilers as well as 17% higher compared to single heat pumps. [ABSTRACT FROM AUTHOR]

In this paper, a row-direction reconstruction algorithm is proposed to recover the lost depth information from a monocular image. The depth of objects in an image is usually determined by the depth of the bottom area of objects. Therefore, using the relationship between the upper and lower areas, a depth map is reconstructed for processing in the row-direction. The relationship is expressed using the energy function and this function is used to estimate the depth. Because the energy function is defined from the various depth cues, the algorithm can be applied to various images. The objective effectiveness of the algorithm is shown using PSNR. [ABSTRACT FROM AUTHOR]

We used daily precipitation data from a global high-resolution climate scenario to analyze the features of future precipitation including extreme and heavy rainfall. The scenario shows that the model reproduces the daily precipitation over South Korea well. The projections show an increase in annual precipitation of approximately 18% in the late 21st century, with the highest increase (38%) occurring in winter. The number of days with daily precipitation of less than 5 mm decreases, but that of daily precipitation of more than 5 mm increases slightly in the latter part of the 21st century. The peak of precipitation days shifted from July to August. The number of days with relatively small amounts of precipitation (10 and 30 mm d −1) increases most substantially in the winter season, but that for large amounts of precipitation (50, 80, 100, and 130 mm d −1) increases most in the summer season. Events with heavy precipitation rates of 100 and 130 mm d −1 are expected to occur in the winter season in the late 21st century, although no such events occurred during the winter season in the reference period. [ABSTRACT FROM AUTHOR]

A new method creating depth information for 2D/3D conversion was proposed. The distance between objects is determined by the distances between objects and light source position which is estimated by the analysis of the image. The estimated lighting value is used to normalize the image. A threshold value is determined by some weighted operation between the original image and the normalized image. By applying the threshold value to the original image, background area is removed. Depth information of interested area is calculated from the lighting changes. The final 3D images converted with the proposed method are used to verify its effectiveness. [ABSTRACT FROM AUTHOR]

A letter to the editor on "Preparation of dip-coated TiO2 photocatalyst on ceramic foam pellets," by Hyunjung Kim, Sanghun Lee, Yoseop Han, and Jaikoo Park in the August 2006 issue is presented.

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]