• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.881-893
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• 2008

The major objective of this study is to investigate the fatigue damage factor evaluation of immovability crossing for railway turnout by the field test and qualitative analysis. From the field test results of the servicing turnout crossing and qualitative analysis with frictional wear which section stiffness decreased, it was evaluated fatigue life of servicing turnout crossing. Most design practices have not taken advantage of the advanced theories in the modern fracture mechanics and finite element analysis due to complexity of analysis as well as the large quantity of vaguely defined parameters in actual designs. This paper considers fatigue problems in turnout crossing using effective analytical and design tools from the field of qualitative constraint reasoning. A set of software modules was developed for fatigue analysis and evaluation, which is easily applicable in engineering practices of designers. The techniques enable the use complex analysis formulations to tackle practical problems with uncertainties, and present the design outcome in two-dimensional design space solution. Appropriate engineering assumptions and judgments in carrying out these procedures, often the most difficult part for practicing engineers, can be partially produced by using qualitative reasoning to define the trends and ranges, interval constraint analysis to derive the controlling parameters, as well as design space to account for practical experience.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.184-191
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• 2023

Nuts are essential components of a healthy diet as they provide nutritional value and bioactive components. Melatonin, is a hormone secreted from the pineal gland of the brain that prevents oxidative damage in various tissues, and also found in plants. This study presents a validation method for extracting and quantitatively analyzing melatonin in nuts, seeds, and beans in Gyeonggi-do; the method utilized chromatographic techniques and optimized extraction procedures, considering the high oil content of nuts. The average content of melatonin in nuts, seeds, and beans was 1200.83 (409.76-2223.56), 934.83 (454.10-1736.60), and 616.46 (494.70-825.12) pg/g, respectively. Melatonin content was higher in the kernel with pellicle than that in the kernel alone in walnuts and chestnuts. Furthermore, the presence of melatonin was lower in newly harvested walnuts, chestnuts, and peanuts than in those stored after being harvested the previous year.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.598-608
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• 2023

To comprehensively grasp the dynamic changes in the coastal terrain and coastal erosion, it is imperative to incorporate temporal and spatial continuity through frequent and continuous monitoring. Recently, there has been a proliferation of research in coastal monitoring using remote sensing, accompanied by advancements in image monitoring and analysis technologies. Remote sensing, typically involves collection of images from aircraft or satellites from a distance, and offers distinct advantages in swiftly and accurately analyzing coastal terrain changes, leading to an escalating trend in its utilization. Remote satellite image-based coastal line detection involves defining measurable coastal lines from satellite images and extracting coastal lines by applying coastal line detection technology. Drawing from the various data sources surveyed in existing literature, this study has comprehensively analyzed encompassing the definition of coastal lines based on satellite images, current status of remote satellite imagery, existing research trends, and evolving landscape of technology for satellite image-based coastal line detection. Based on the results, research directions, on latest trends, practical techniques for ideal coastal line extraction, and enhanced integration with advanced digital monitoring were proposed. To effectively capture the changing trends and erosion levels across the entire Korean Peninsula in future, it is vital to move beyond localized monitoring and establish an active monitoring framework using digital monitoring, such as broad-scale satellite imagery. In light of these results, it is anticipated that the coastal line detection field will expedite the progression of ongoing research practices and analytical technologies.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.939-953
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• 2023

Shallow water equations (SWE) serve as fundamental equations governing the movement of the water. Traditional numerical approaches for solving these equations generally face various challenges, such as sensitivity to mesh generation, and numerical oscillation, or become more computationally unstable around shock and discontinuities regions. In this study, we present a novel approach that leverages the power of physics-informed neural networks (PINNs) to approximate the solution of the SWE. PINNs integrate physical law directly into the neural network architecture, enabling the accurate approximation of solutions to the SWE. We provide a comprehensive methodology for formulating the SWE within the PINNs framework, encompassing network architecture, training strategy, and data generation techniques. Through the results obtained from experiments, we found that PINNs could be an accurate output solution of SWE when its results were compared with the analytical method. In addition, PINNs also present better performance over the Artificial Neural Network. This study highlights the transformative potential of PINNs in revolutionizing water resources research, offering a new paradigm for accurate and efficient solutions to the SVE.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.10-20
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• 2024

RNA-sequencing (RNA-seq) is a technique used for providing global patterns of transcriptomes in samples. However, it can only provide the average gene expression across cells and does not address the heterogeneity within the samples. The advances in single-cell RNA sequencing (scRNA-seq) technology have revolutionized our understanding of heterogeneity and the dynamics of gene expression at the single-cell level. For example, scRNA-seq allows us to identify the cell types in complex tissues, which can provide information regarding the alteration of the cell population by perturbations, such as genetic modification. Since its initial introduction, scRNA-seq has rapidly become popular, leading to the development of a huge number of bioinformatic tools. However, the analysis of the big dataset generated from scRNA-seq requires a general understanding of the preprocessing of the dataset and a variety of analytical techniques. Here, we present an overview of the workflow involved in analyzing the scRNA-seq dataset. First, we describe the preprocessing of the dataset, including quality control, normalization, and dimensionality reduction. Then, we introduce the downstream analysis provided with the most commonly used computational packages. This review aims to provide a workflow guideline for new researchers interested in this field.

• Journal of Ginseng Research
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• v.48 no.5
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• pp.474-480
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• 2024

Background: Recent years have witnessed increasing interest in the high amount of ocotillol-type saponin in Panax vietnamensis, particularly in relation to majonoside R2 (MR2). This unique 3%-5% MR2 content impart Ngoc Linh and Lai Chau ginsengs with unique pharmacological activities. However, in the commercial domain, unauthentic species have infiltrated and significantly hindered access to the authentic, efficacious variety. Thus, suitable analytical techniques for distinguishing authentic Vietnamese ginseng species from others is becoming increasingly crucial. Therefore, MR2 is attracting considerable attention as a target requiring effective management measures. Methods: An enzyme-linked immunosorbent assay (ELISA) was developed by producing monoclonal antibodies against MR2 (mAb 16E11). The method was thoroughly validated, and the potential of the immunoassay was confirmed by high-performance liquid chromatography with ultraviolet spectroscopy. Furthermore, ELISA was applied to the assessment of the MR2 concentrations of various Panax spp., including Korean, American, and Japanese ginsengs. Results and conclusions: An icELISA using mAb 16E11 exhibited linearity between 3.91 and 250 ng/mL of MR2, with detection and quantification limits of 1.53 and 2.50 - 46.6 ng/mL, respectively. Based on this study, the developed icELISA using mAb 16E11 could be a valuable tool for analyzing MR2 level to distinguish authentic Ngoc Linh and Lai Chau ginsengs from unauthentic ones. Furthermore, the analysis of the samples demonstrated that Ngoc Linh and Lai Chau ginsengs exhibit a notably higher MR2 value than all other Panax spp. Thus, MR2 might be their ideal marker compound, and various bioactivities of this species should be explored.

• Tunnel and Underground Space
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• v.34 no.4
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• pp.355-373
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• 2024

The Generalized Hoek-Brown (GHB) criterion is a nonlinear failure criterion specialized for rock engineering applications and has recently seen increased usage. However, the GHB criterion expresses the relationship between minimum and maximum principal stresses at failure, and when GSI≠100, it has disadvantage of being difficult to express as an explicit relationship between the normal and shear stresses acting on the failure plane, i.e., as a Mohr failure envelope. This disadvantage makes it challenging to apply the GHB criterion in numerical analysis techniques such as limit equilibrium analysis, upper-bound limit analysis, and the critical plane approach. Consequently, recent studies have attempted to express the GHB Mohr failure envelope as an approximate analytical formula, and there is still a need for continued interest in related research. This study presents improved formulations for the approximate GHB Mohr failure envelope, offering higher accuracy in predicting shear strength compared to existing formulas. The improved formulation process employs a method to enhance the approximation accuracy of the tangential friction angle and utilizes the tangent line equation of the nonlinear GHB failure envelope to improve the accuracy of shear strength approximation. In the latter part of this paper, the advantages and limitations of the proposed approximate GHB failure envelopes in terms of shear strength prediction accuracy and calculation time are discussed.

• Analytical Science and Technology
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• v.27 no.1
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• pp.41-59
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• 2014

The aims of this work were the identification and the classification of fresh lubricants and used engine oils of vehicles for the application in forensic science field-80 kinds of fresh lubricants were purchased and 86 kinds of used engine oils were sampled from 24 kinds of diesel and gasoline vehicles with different driving conditions. The sample of lubricants and used engine oils were analyzed by GC/MS. The Bayesian model technique was developed for classification or identification. Both the wavelet fitting and the principal component analysis (PCA) techniques as a data dimension reduction were applied. In fresh lubricants classification, the rates of matching by Bayesian model technique with wavelet fitting and PCA were 97.5% and 96.7%, respectively. The Bayesian model technique with wavelet fitting was better to classify lubricants than it with PCA based on dimension reduction. And we selected the Bayesian model technique with wavelet fitting for classification of lubricants. The other experiment was the analysis of used engine oils which were collected from vehicles with the several mileage up to 5,000 km after replacing engine oil. The eighty six kinds of used engine oil sample with the mileage were collected. In vehicle classification (total 24 classes), the rate of matching by Bayesian model with wavelet fitting was 86.4%. However, in the vehicle's fuel type classification (whether it is gasoline vehicle or diesel vehicle, only total 2 classes), the rate of matching was 99.6%. In the used engine oil brands classification (total 6 classes), the rate of matching was 97.3%.

• Analytical Science and Technology
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• v.16 no.4
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• pp.292-298
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• 2003

In this study, the photooxidation and ozonation of humic acid (HA) in aqueous solution were conducted and the treated HA samples at different reaction time were analyzed using ultrafiltration techniques to evaluate the change of their molecular size distributions with its DOC removal. Molecular size distribution of untreated HA showed 41.5% in higher molecular size fractions (>30,000 daltons) and 15.2% in much smaller molecular size fraction (<500 daltons). As UV irradiation time was increased, it was observed that the degradation of the large molecules of the fraction of >30,000 daltons into much smaller molecules was increased. In UV system, the HA molecules of the fraction of <500 daltons became significantly more and its percentage was increased from 35.3% (UV only irradiation) to 58.9% ($UV/TiO_2$) and 87.8% ($UV/H_2O_2$) in the presence of the photocatalysis. Otherwise, ozonation of HA produced mainly the fraction of medium molecular size ranging from 3,000 to 30,000 daltons with much lower portion (<~7%) in the fraction of <500 daltons. In ozone only system, the fraction of 30,000~10,000 daltons occupied in 41.5% at 60 min of ozonation time. In $O_3/H_2O_2$ system, the fraction of 30,000~10,000 daltons and 10,000~3,000 daltons occupied in 38.9% and 36.2% respectively. Based on these results, we suggested applicable treatment process which could be combined with $UV/H_2O_2$, $UV/TiO_2$ and $O_3$, $O_3/H_2O_2$ system for more effective removal of humic acid in water treatment.

• Analytical Science and Technology
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• v.29 no.3
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• pp.142-153
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• 2016

In crime scene investigation, fingerprint identification is regarded to be one of the most important techniques for personal identification. However, objective and unbiased evaluation methods that would compare the fingerprints with diverse available and developing methods are currently lacking. To develop an objective and quantitative method to improve fingerprint evaluation, a preliminary study was performed to extract useful research information from the analysis with densitometric image analysis (CP Atlas 2.0) and the Automated Fingerprint Identification System (AFIS) for the developed fingerprints on porous surfaces. First, inked fingerprints obtained by varying pressure (kg.f) and pressing time (sec.) to find optimal conditions for obtaining fingerprint samples were analyzed, because they could provide fingerprints of a relatively uniform quality. The extracted number of minutiae from the analysis with AFIS was compared with the calculated areas of friction ridge peaks from the image analysis. Inked fingerprints with a pressing pressure of 1.0 kg.f for 5 seconds provided the most visually clear fingerprints, the highest number of minutiae points, and the largest average area of the peaks of the friction ridge. In addition, the images of the developed latent fingerprints on thermal paper with the iodine fuming method were analyzed. Fingerprinting condition of 1.0 kg.f/5 sec was also found to be optimal when generating highest minutiae number and the largest average area of peaks of ridges. Additionally, when the concentration of ninhydrin solution (0.5 % vs. 5 %) was used to compare the developed latent fingerprints on print paper, the best fingerprinting condition was 2.0 kg.f/5 sec and 5 % of ninhydrin concentration. It was confirmed that the larger the average area of the peaks generated by the image analysis, the higher the number of minutiae points was found. With additional tests for fingerprint evaluation using the densitometric image analysis, this method can prove to be a new quantitative and objective assessment method for fingerprint development.