• Corrosion Science and Technology
• /
• v.19 no.2
• /
• pp.66-74
• /
• 2020

In this paper, the author's team has carried out a comparative experimental study on the corrosion characteristics of Q235 steel commonly used in large-scale storage tanks under the specific bottom water environment found with Russian and Daqing crude oil. It was found that there is a certain degree of uniform or local corrosion on the tank floor depending on the kind of bottom water. The bottom water corrosion of Daqing crude oil is a uniform corrosion caused by carbon dioxide. While the Russian crude oil bottom water corrosion is clearly local corrosion caused by co-corrosion of carbon dioxide and hydrogen sulfide, here the corrosion rate is obviously higher than that caused by Daqing crude oil. There are two modes of storage tank inspection and maintenance that have been currently adopted by Chinese refining and chemical enterprises: a regular inspection mode and a API581-2016 risk-based detection mode. These modes have been effectively combined to form an intelligent tank inspection and maintenance mode, software tools to support this intelligent inspection and maintenance management have been developed.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.8
• /
• pp.15-23
• /
• 2020

Based on the theoretical underpinnings of the agency theory and liquidity theory, the purpose of this study is to show how managers who want to enhance the performance of Pakistan's non-financial sector can use liquidity policy in relation to corporate governance. Nowadays, Pakistan is facing a severe liquidity crisis; this study contributes by examining the mediating role of liquidity on the link of corporate governance-performance. We use data from 63 firms from 2010 to 2018, excluding 17 outliers. To analyze the data, we use the Seemingly Unrelated Regression (SURE) model and nlcom-Stata test. Our findings support the mediating role of liquidity on the link between corporate governance and performance. In addition, the results show that corporate governance improves performance. Furthermore, the study supports a significant positive association of liquidity and performance. For robustness, we use two performance variables - return on assets (ROA) and Tobin's q (TQ) - where ROA represents full mediation and TQ indicates partial mediation. This study helps to use liquidity policy to strengthen the inside and outside dimensions of corporate governance mechanisms that improve the performance of firms. Overall, these findings suggest better disclosure, transparency, and solutions to auditing issues that add value to the firms.

• Journal of Oral Medicine and Pain
• /
• v.43 no.2
• /
• pp.52-55
• /
• 2018

In the present case study, we reported a female patient with sialodochitis fibrinosa in which a conservative ultrasound (US)-guided irrigation method was used to relieve her symptoms. A 30-year-old female patient visited Kyung Hee University Dental Hospital with chief complaints of persistent swelling and discomfort in the left facial area. Her primary symptom was facial swelling that was accompanied by neuropathological symptoms, such as itching, tingling, and warmth that usually continued for 3 to 4 days. During clinical examination of orofacial area, mild swelling and fever were noted in the left face including parotid region, and mild induration could be felt at the corresponding site; sialadenitis of the left parotid gland was tentatively diagnosed. Herein, we performed intraductal irrigation of the left parotid gland in three times per month and prescribed some medication. Thus, her signs and symptoms have been improved, and she did not experience a recurrence for 12-month follow-up to date. This study can support the usefulness of the US-guided irrigation method to treat the sialodochitis fibrinosa without remarkable side effects.

• Honam Mathematical Journal
• /
• v.8 no.1
• /
• pp.51-74
• /
• 1986

The thery of measure is significant in that we extend from it to the theory of integration. AS specific metric outer measures we can take Hausdorff outer measure and Lebesgue-Stieltjes outer measure connecting measure with monotone functions.([12]) The purpose of this paper is to find some properties of Lebesgue-Stieltjes measure by extending it from $R^1$ to $R^n(n{\geq}1)$ $({\S}3)$ and differentiation of the integral defined by Borel measure $({\S}4)$. If in detail, as follows. We proved that if $_n{\lambda}_{f}^{\ast}$ is Lebesgue-Stieltjes outer measure defined on a finite monotone increasing function $f:R{\rightarrow}R$ with the right continuity, then $$_n{\lambda}_{f}^{\ast}(I)=\prod_{j=1}^{n}(f(b_j)-f(a_j))$$, where $I={(x_1,...,x_n){\mid}a_j$<$x_j{\leq}b_j,\;j=1,...,n}$. (Theorem 3.6). We've reached the conclusion of an extension of Lebesgue Differentiation Theorem in the course of proving that the class of continuous function on $R^n$ with compact support is dense in $L^p(d{\mu})$ ($1{\leq$}p<$\infty$) (Proposition 2.4). That is, if f is locally $\mu$-integrable on $R^n$, then $\lim_{h\to\0}\left(\frac{1}{{\mu}(Q_x(h))}\right)\int_{Qx(h)}f\;d{\mu}=f(x)\;a.e.(\mu)$.

• CELLMED
• /
• v.8 no.4
• /
• pp.21.1-21.2
• /
• 2018

The aim of this article is to argue that repeated singing helps to feel 'misery loves company.' Folksong is popular music in the past. Korean folk songs have almost repetitive chorus. The repetitive refrain is made easy for everyone to follow. So, people become comrades who share the chorus together. Repetitive music makes people more intimate and more intimate. So, people feel that they share thoughts and feelings with music. It gives me energy to never give in to destiny. So, they encourage each other to be worth living. They sing together and sympathize and comfort each other's pain. 'Hook song' is the most popular form in these days in Korean music. The form of K-pop (Korean pop), which is gaining popularity worldwide, has many repetitions and concentration of melody. BTS (Bang Tan Sonyundan, Boyband) also tells teens around the world through repetitive melodies that "Let's share our joy and sorrow." This is the highest value of music therapy. BTS is a Korean boy band that has gained a worldwide reputation. Recently, their songs are affecting teenagers all over the world. In this way, the author thinks that the repetition of folk songs was reborn as a 'Hook song' and the repetitive form of music is a good way to give support to anyone. The author thinks this is best accomplished by singing 'misery loves company.'

• The Korean Journal of Emergency Medical Services
• /
• v.26 no.1
• /
• pp.37-56
• /
• 2022

Purpose: This study aimed to identify and present suitable recognition types of policy alternative for before and after response, according to the recognition types of problems in response to violence. Methods: This study investigated 36 EMT's of 17 cities and provinces nationwide. The study was approved by the Kongju National University Institute Review Board (KNU_IRB_2021-17). Data were collected from May 1, 2021 to August 30, 2021 and analyzed by Q factor analysis using the PC-QUNAL program. Results: Recognition types of the problem in 119 EMT's response to violence were described as "I type; lack of professional manpower," "II type; inadequate policy on violence," and "III type; lack of awareness on the emergency field." Recognition types of policy alternative on response to violence by 119 EMT's were described as "Itype; training and public relations oriented," "II type; work environment improvement," "III type; violence handling specialization demand," and "IV type; recovery support seeker." Conclusion: This study provides the foundation required to develop and implement the policies regarding the response to violence; therefore, contributing to EMT's provision.

• Journal of Korean Association for Spatial Structures
• /
• v.23 no.3
• /
• pp.87-94
• /
• 2023

Chloride is one of the most common threats to reinforced concrete (RC) durability. Alkaline environment of concrete makes a passive layer on the surface of reinforcement bars that prevents the bar from corrosion. However, when the chloride concentration amount at the reinforcement bar reaches a certain level, deterioration of the passive protection layer occurs, causing corrosion and ultimately reducing the structure's safety and durability. Therefore, understanding the chloride diffusion and its prediction are important to evaluate the safety and durability of RC structure. In this study, the chloride diffusion coefficient is predicted by machine learning techniques. Various machine learning techniques such as multiple linear regression, decision tree, random forest, support vector machine, artificial neural networks, extreme gradient boosting annd k-nearest neighbor were used and accuracy of there models were compared. In order to evaluate the accuracy, root mean square error (RMSE), mean square error (MSE), mean absolute error (MAE) and coefficient of determination (R2) were used as prediction performance indices. The k-fold cross-validation procedure was used to estimate the performance of machine learning models when making predictions on data not used during training. Grid search was applied to hyperparameter optimization. It has been shown from numerical simulation that ensemble learning methods such as random forest and extreme gradient boosting successfully predicted the chloride diffusion coefficient and artificial neural networks also provided accurate result.

• Korean Journal of Biological Psychiatry
• /
• v.19 no.3
• /
• pp.128-133
• /
• 2012

Objectives : Located on chromosome 10q22-q23, the human neuregulin 3 (NRG3) is suggested as a strong positional and functional candidate gene involved in the pathogenesis of schizophrenia. Several case-control studies examining the association between polymorphisms on NRG3 gene with schizophrenia and/or its traits (such as delusion) have been reported recently in cohorts of Han Chinese, Ashkenazi Jews, Australians, white Americans of Western European ancestry and Koreans. Thus, this study aimed to investigate the association of one SNP in exon 9 (rs2295933) of NRG3 gene with the risk of schizophrenia in a Korean population. Methods : Using TaqMan assay, rs2295933 in the exon 9 of NRG3 was genotyped in 435 patients with schizophrenia as cases and 393 unrelated healthy individuals as controls. Differences in frequency distributions were analyzed using logistic regression models following various modes of genetic inheritance and controlling for age and sex as covariates. Results : Subsequent analysis revealed that the frequency distribution of rs2295933 of NRG3 was not different between schizophrenia patients and healthy controls of Korean ethnicity. Conclusions : This study does not support the role of NRG3 in schizophrenia in a Korean population.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.12
• /
• pp.1367-1372
• /
• 2014

As the awareness of the environmental crisis has recently increased around the world, numerous studies in the transport industry have been conducted to solve this problem through lightweight car bodies. The hot-stamping process has been presented as solution to achieve a light weight. Hot-stamping is a method that is used to obtain ultra-high strength steel (1,500 MPa or greater) by simultaneously forming and cooling boron steel in a press die after heating it to a temperature of $900^{\circ}C$ or above. This study involved a, fundamental examination of laser parameters to investigate the laser weldability of boron steel. As a result, the following optimum parameters for the shielding gas were found: Q = 20 l/min, ${\alpha}=40^{\circ}$, d = 20mm, and l = 0 mm. The hardness of butt weldment increasesed sharply as a result of martensite formation at the fusion zone.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.2
• /
• pp.263-268
• /
• 2016

A rapid increase of data amount, used in ship-to-ship transmission of safety and logistics information, ships in the inland sea have trouble transmitting real-time information transmission due to an increase in traffic load caused by data transmitted by land station and offshore ships. In this study, therefore, communication is carried out by adaptively controlling the detailed beam width based on the distribution of offshore ships in land station durable in marine environment. Then after the adaptive sector system enabling real-time communication support between ships concentrated in an inland sea and land station is applied, the performance verification is conducted based on the respective Call Blocking Rates of an omnidirectional antenna, fisted sector system, and adaptive sector system. The performance verification result shows that adaptive sector system has better performance than the fixed sector system as the density of ship, q value, increases, and that the smaller the beam width is, the better performance of adaptive sector system will be.