scholarly journals Suggestion of advanced regression model on friction angle of fault gouge in South Korea

2021 ◽  
Author(s):  
Seong-Woo Moon ◽  
Hyun-Seok Yun ◽  
Yong-Seok Seo
Keyword(s):  
South Korea ◽  
Regression Model ◽  
Friction Angle ◽  
Fault Gouge

scholarly journals Shear Mechanical Behaviours and Multistrength Parameter Characteristics of Fault Gouge

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Han Bao ◽  
Qun Qi ◽  
Hengxing Lan ◽  
Changgen Yan ◽  
Wei Xu ◽  
...  
Keyword(s):  
Water Content ◽  
Normal Stress ◽  
Clay Minerals ◽  
Residual Strength ◽  
Failure Modes ◽  
Friction Angle ◽  
Strength Properties ◽  
Fault Gouge ◽  
Normal Stresses ◽  
Fault Gouges

Fault gouge has special mechanical properties and remarkable engineering effects. Using a ring shear test, the strength properties of the differently colored remolded fault gouges of the Shendaogou Fault in Yan’an were studied by changing moisture contents and normal stresses. Chlorite and illite are the main clay minerals in fault gouges; differences in mineral composition make fault gouges appear in different colors. Besides clay minerals, the dried fault gouges disintegration in water is also due to the transformation of gypsum. The gradation of green fault gouge and multicolor fault gouge is better than that of the red fault gouge, while the fault gouges’ strain softening properties become weaker as the coarse grain content increases. Affected by water content and normal stress, the shear planes can be divided into three failure modes: peeling failure, grooved failure, and sliding failure. With the increase of water content, there will be a significant weakening on cohesion and friction angle. A new parameter, the “Normal Stress Threshold (NST),” is introduced as a critical value for the emergence of the strain hardening phenomenon, and the NSTs of different fault gouges are significantly different. The functions obtained from the relation of residual strength, peak strength, and normal stress can be used to calculate shear strength parameters under any normal stresses. In addition, the residual strength of fault gouge is obviously different from clay and loess, which can be qualitatively explained by clay particle contents.

scholarly journals Is greater generic competition also linked to lower drug prices in South Korea?

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyung-Bok Son
Keyword(s):  
South Korea ◽  
Regression Model ◽  
Multivariate Regression ◽  
Price Competition ◽  
Generic Drugs ◽  
Anatomical Therapeutic Chemical ◽  
Multivariate Regression Model ◽  
Generic Competition ◽  
Market Competitiveness ◽  
Maximum Price

Abstract Background Although the association between the price of generic drugs and market competitiveness has been explored in various high-income countries, this association has not been empirically evaluated in South Korea. We aim to determine the association between the prices of generic drugs and market competitiveness in South Korea. Methods A list of originator drugs approved by the national authority from 2000 to 2019 and their corresponding generic drugs were grouped along with the baseline information. The market was categorized into four groups based on the number of manufacturers: duopoly (2 manufacturers); low- (3–25 manufacturers); medium- (26–75 manufacturers); and high-competition (more than 76 manufacturers) markets. Price variance, calculated as the difference between the maximum price and minimum price divided by the maximum price, was obtained. A multivariate regression model was applied to regress price variance on the characteristics of market competitiveness, controlling for the characteristics of the originator drugs and their price level in the market. Results A total of 986 originator drugs were identified and then divided into duopoly (31%), low- (56%), medium- (9%), and high-competition (4%) markets; the median of the price variance for these markets was 0.013, 0.077, 0.200, and 0.228, respectively. In a multivariate regression model, price variance was associated with the characteristics of the originator drug, including the Anatomical Therapeutic Chemical classification, the route of administration, and the approval year. Controlling for the characteristics of the originator drugs, market competitiveness was positively associated with price variance. Conclusions The positive association between price variance and market competitiveness is still consistent in South Korea, where rare price competition among a large number of generic manufacturers has been reported. However, no significant price variance was observed between medium- and high-competition markets. These findings support policies for managing a large number of generic manufacturers in South Korea.

scholarly journals THE RELATION BETWEEN ENGAGEMENT QUALITY CONTROL REVIEW HOURS AND AUDITOR CHANGES: EVIDENCE FROM SOUTH KOREA

2021 ◽  
Vol 22 (5) ◽  
pp. 1269-1287
Author(s):  
Jae-Won Song ◽  
Yong-Shik Kim
Keyword(s):  
Quality Control ◽  
Empirical Study ◽  
South Korea ◽  
Regression Model ◽  
Audit Fees ◽  
Positive Relation ◽  
Moderating Effects ◽  
Audit Risk ◽  
Logit Regression ◽  
Logit Regression Model

The purpose of this study is to analyze whether engagement quality control review (EQCR) hours affect auditor changes and whether abnormal audit fees and changes in management have moderating effects on the relation between EQCR hours and auditor changes. The logit regression model is designed to investigate the relation between EQCR hours and auditor changes. The study finds evidence that EQCR hours are higher before auditors are changed. It also documents that abnormal audit fees weaken and that changes in management strengthen the positive relation between EQCR hours and auditor changes. In summary, high EQCR hours increase the probability of auditor changes, and the results imply that EQCR hours are a proxy for the audit risk perceived by auditors. This research is the first empirical study to test the relation between EQCR hours and auditor changes.

Disclosure of corporate sustainability performance and firm performance in Asia

2018 ◽  
Vol 26 (4) ◽  
pp. 414-443 ◽  
Author(s):  
Najul Laskar ◽  
Santi Gopal Maji
Keyword(s):  
Developing Countries ◽  
Firm Performance ◽  
Panel Data ◽  
South Korea ◽  
Regression Model ◽  
Corporate Sustainability ◽  
Content Type ◽  
Sustainability Performance ◽  
Corporate Sustainability Performance ◽  
The Impact

Purpose The purpose of this paper is to examine the disclosure pattern of corporate sustainability (CS) and the influence of sustainability reporting on firm performance of four countries in Asia – Japan, South Korea, Indonesia and India. Design/methodology/approach The authors have collected the sustainability reports and annual reports of 111 firms from four Asian countries for a period of six years. Based on the framework of Global Reporting Initiatives (GRI, 3 and 3.1), content analysis is used for calculating the disclosure score of corporate sustainability performance (CSP). These scores are further used to examine the impact on firm performance by employing a panel data regression model. Findings The study finds that the average level and quality of disclosure are the highest for Japanese firms, followed by India and South Korea. However, in the case of Indonesia, the average score is very low. Further, the study finds a significant difference in the disclosure of overall sustainability as well as components of sustainability between the countries. The regression results indicate the positive impact of CSP (both in terms of level and quality) on MBR. Specifically, the outcome of the regression model reveals that both the level and quality disclosure of CS are crucial for enhancing firm value for both the developed and developing countries of Asia. Moreover, the relative influence of CSP (both in terms of level and quality) on firm performance is found to be more in developed countries than the developing countries of Asia. Originality/value This is the first comprehensive study in the Asian context to investigate the disclosure pattern of CSP and also examine the association between CSP and firm performance by employing the panel data model. The outcome of this study is useful for policy implication.

scholarly journals Relationship between Chemical Weathering Indices and Shear Strength of Highly and Completely Weathered Granite in South Korea

2021 ◽  
Vol 11 (3) ◽  
pp. 911
Author(s):  
Seung-Hwan Lee ◽  
Choong-Ki Chung ◽  
Young-Woo Song ◽  
Sang-Inn Woo
Keyword(s):  
Shear Strength ◽  
South Korea ◽  
Chemical Weathering ◽  
Friction Angle ◽  
Standard Penetration Test ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Weathered Granite ◽  
Weathering Indices ◽  
Chemical Index Of Alteration

In South Korea, weathered granite is widely distributed and has been used as a bearing stratum for various structures. Therefore, it is important to determine the shear strength of the weathered granite. However, it is difficult to obtain reliable shear strength parameters with laboratory tests or standard penetration test (SPT) because weathered granite is easily crushed during the sampling process, and the penetrability of SPT is not secured. On the other hand, it is well known that weathering affects the variation of geotechnical properties. Based on this concept, this study reports a correlation between the shear strength parameters and the chemical weathering indices of the weathered granite. In this study, the pressuremeter test (PMT) was adopted to determine the friction angle of the weathered granite. For the identical granite, the chemical weathering indices (Vogt’s Ratio (VR), Chemical Index of Alteration (CIA), and Mobiles Index (Imob)) were measured by X-ray fluorescence (XRF). An estimating model considering both site-specific characteristics and degree of weathering was used, and the CIA showed the best correlation (R2 = 0.66) with friction angle among the weathering indices. Since the ratio of measured friction angle over the predicted one was distributed in the range from 0.8 to 1.2, it is more reasonable to predict friction angles based on CIA comparing to using the SPT-N value. It can contribute to a better estimation of friction angles of weathered granite.

scholarly journals Population-level alcohol consumption and suicide mortality rate in South Korea: An application of multivariable spatial regression model

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Yunho Yeom
Keyword(s):  
Alcohol Consumption ◽  
Mortality Rate ◽  
South Korea ◽  
Regression Model ◽  
Church Attendance ◽  
Spatial Regression ◽  
Population Level ◽  
Suicide Mortality ◽  
Consumption Pattern ◽  
Spatial Regression Model

This research estimates the contextual effects of populationlevel alcohol consumption on the average suicide mortality rate (SMR) in South Korea from 2013 to 2015. The effect was estimated not only in relation to the risk factors of suicide, such as divorce and being elderly, but also protective factors, such as church attendance and educational attainment. Using a multivariable spatial regression model, results show that only excessive population-level alcohol consumption pattern had a positive effect on SMR by increasing 0.24 standardized units in the SMR; the moderate pattern, however, had no significant impact. These results imply that the excessive population-level alcohol consumption pattern is a risk factor with respect to SMR. This research suggests the implementation of policies to control population- level alcohol consumption, based on a concern for public health, to reduce the suicide risk in South Korea.

scholarly journals Estimation of the final size of the second phase of the coronavirus COVID 19 epidemic by the logistic model

2020 ◽  
Author(s):  
Milan Batista
Keyword(s):  
South Korea ◽  
Regression Model ◽  
Logistic Model ◽  
Logistic Growth ◽  
Second Phase ◽  
Peak Time ◽  
Final Size ◽  
The World ◽  
Growth Regression

AbstractIn the note, the logistic growth regression model is used for the estimation of the final size and its peak time of the coronavirus epidemic in China, South Korea, and the rest of the World.

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