• Structural Engineering and Mechanics
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• v.85 no.6
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• pp.825-835
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• 2023

The effective buckling length factor is an important parameter in the elastic buckling analysis of steel structures. The present article aims at developing a new method that allows the determination of the buckling factor values for frames. The novelty of the method is that it considers the interaction between the bracing and the elastic supports for asymmetrical frames in particular. The approach consists in isolating a critical column within the frame and evaluating the rotational and translational stiffness of its restraints to obtain the critical buckling load. This can be achieved by introducing, through a dimensionless parameter 𝜙_i, the effects of coupling between the axial loading and bending stiffness of the columns, on the classical stability functions. Subsequently, comparative, and parametric studies conducted on several frames are presented for assessing the influence of geometry, loading, bracing, and support conditions of the frame columns on the value of the effective buckling length factor K. The results show that the formulas recommended by different approaches can give rather inaccurate values of K, especially in the case of asymmetric frames. The expressions used refer solely to local stiffness distributions, and not to the overall behavior of the structure.

• Tuberculosis and Respiratory Diseases
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• v.85 no.3
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• pp.221-226
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• 2022

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation due to chronic airway inflammation and destruction of the alveolar structure from persistent exposure to oxidative stress. The body has various antioxidant mechanisms for efficiently coping with such oxidative stress. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) is a representative system. Dysregulation of the Nrf2-ARE pathway is responsible for the development and promotion of COPD. Furthermore, COPD severity is also closely related to this pathway. There has been a clinical impetus to use Nrf2 for diagnostic and therapeutic purposes. Therefore, in this work, we systematically reviewed the clinical significance of Nrf2 in COPD patients, and discuss the value of Nrf2 as a potential COPD biomarker.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.187-194
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• 2002

It has been reported that cracks in mechanical joints is generally under mixed-mode and there is critical inclined angle at which mode I stress intensity factor becomes maximum. The crack propagates in arbitrary direction and thus the prediction of crack growth path is needed to provide against crack propagation or examine safety. In order to evaluate the fatigue life of cracks in mechanical joints, horizontal crack normal to the applied load and located on minimum cross section is major concern but critical inclined crack must also be considered. In this paper mixed-mode fatigue crack growth test is performed far horizontal crack and critical inclined crack in mechanical joints. Fatigue crack growth path is predicted by maximum tangential stress criterion using stress intensity factor obtained from weight function method, and fatigue crack growth rates of horizontal and inclined crack are compared.

• International Journal of Automotive Technology
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• v.7 no.6
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• pp.703-714
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• 2006

The growing concern surrounding rollover incidences and consequences of Sports Utility Vehicles(SUV) have prompted to investigate the sensitivity of critical vehicle parameters on rollover. In this paper, dynamic rollover simulation of Sports Utility Vehicles is carried out using a validated nonlinear vehicle model in Matlab/Simulink. A standard model is considered and critical vehicle parameters like CG height, track width and wheel base are varied within chosen specified limits to study its influence on roll behavior during a Fishhook steering maneuver. A roll stability criterion based on Two Wheel Lift Off(TWLO) phenomenon is adopted for rollover propensity prediction. Further dynamic rollover characteristics of the vehicle are correlated with Static Stability Factor(SSF), Roll Stability Factor(RSF) and Two Wheel Lift Off Velocity(TWLV). These findings will be of immense help to SUV chassis designers to determine safety limits of critical vehicle parameters and minimize rollover incidences.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.667-671
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• 2005

Analytical hierarchy process (AHP) is a potential decision making method in management that can be used in project management as well. Lack of productivity is perhaps the number one problem confronting in the construction industry. There are numerous factors which affect the productivity of a construction project, so it is necessary to find out the critical factors giving birth to productivity. In this paper, construction productivity is taken as example for the demonstration of the AHP application to find out the critical productivity factor in which the Level 1 is taken as selection of critical productivity factor, Level 2 as construction parties and Level 3 as productivity factors group. The outcome of this study is beneficial to the entire constructional professionals for applying the AHP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1052-1059
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• 2009

Health care has become one of the paramount issues of the 21st century as governments and individuals grapples the complex problems associated with contemporary medical care such as cost, affordability, and shifting demographic trends. The purpose of this study was to develop the critical success factors of medical tourism for health-care organizations and to measure the wights of these factors. For this purpose, we gathered the data from doctors, travelling agencies and scholars. about the success factors of medical tourism. Exploratory and confirmatory factor analysis was carried out to determine the factors as the Critical Success Factors of medical tourism. We did also the research to evaluate the validity and reliability of these factors. After that the Analytical Hierarchy Process (AHP) was applied to analyze the weight and significances among these factors. Factor analysis resulted in 15 major factors (Eigenvalue > 1.0). The AHP analysis showed the list of Critical Success Factors weighted by its significance priorities. The recommendable degree of reliability and validity suggests that these factors could be the valuable refences for the policy making process of the medical tourism in Korea.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.93-98
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• 2012

The rapid change of business environments request the company to act more smart and intelligent in making business strategies and planning the business processes. To meet this requirement, we need to have smart Business Intelligent System(hereinafter "BI") in the company. On the one hand, many korean companies had already installed BI system, and the other hand some companies have plans to implement BI Systems additionally to their Information System. It is very important to have the pictures which factors are critical to the successful implementation of BI, and to survey which critical success factor(hereinafter CSF) are important compared to each factors. In this paper data was gathered from companies already have their BI Systems. We measured IT-Infra maturity, User Education, and Company Organization, and Company Business Strategy, which are the critical success factors for the BI System. After surveying the CSF of BI System, we measured the weights among these factors by AHP. Factor analysis resulted in 6 major factors (Eigenvalue > 1.0), and the AHP analysis showed the list of CSF's weight list according to its significance priorities. The results of this paper could be the valuable references for the implementing process of the BI System in korean company.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.215-220
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• 2001

The objective of this study is to examine the fracture characteristics of concrete at early ages such as critical stress intensity factor, critical crack-tip opening displacement, fracture energy based on the concepts of the effective-elastic crack model and the cohesive crack model. A wedge splitting test for Mode I was performed on cubic wedge specimens with a notch at the edge. By varying strength and age, load-crack mouth opening displacement curves were obtained and the results were analyzed by linear elastic fracture mechanics. The results from the test and analysis showed that critical stress intensity factor and fracture energy increased, and critical crack-tip opening displacement decreased with concrete age from 1 day to 28 days. The obtained fracture parameters at early ages may be used as a fracture criterion and an input data for finite element analysis of concrete at early ages.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.1 s.256
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• pp.40-50
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• 2007

The present contribution describes the application of elliptic-blending second moment closure to predict the gas cooling process of turbulent super-critical carbon dioxide flow in a square cross-sectioned duct. The gas cooling process under super-critical state experiences a drastic change in thermodynamic and transport properties. Redistributive terms in the Reynolds stress and turbulent heat flux equations are modeled by an elliptic-blending second moment closure in order to represent strongly non-homogeneous effects produced by the presence of walls. The main feature of Durbin's elliptic relaxation second moment closure that accounts for the nonlocal character of pressure-velocity gradient correlation and the near-wall inhomogeneity guaranteed by the elliptic blending second moment closure.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.509-516
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• 2001

As the first step for the application of seismic landslide hazard maps to domestic cases, two types of hazard maps on Ul-joo from pseudostatic analysis and Newmark sliding block analysis are constructed and comllared. Arcview, the GIS program and the 1:5,000 digital maps of the test-site are used for the construction of hazard maps and tile parameters for the analyses are determined by seismic survey and laboratory tests. The results from the pseudostatic analysis have more conservative values of lower critical slope angles, although the results from the two different analyses have similar tendencies. In detail, with increasing the peak ground acceleration, the difference between the two analyses in the critical slope angle increases, while the difference decreases with increasing the maximum soil depth.