• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.577-584
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• 2003

This study investigated the modeling of dissolution Diesel to estimate the behavior of contaminants in the ground. The modeling based on the initial concentration change considering dissolution potential of pure Diesel and Xylene was performed using VISUAL MODFLOW, and was compared with general modeling ignored the initial concentration change condition.

• Structural Engineering and Mechanics
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• v.74 no.4
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• pp.559-565
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• 2020

This paper intends to progress models to accurately estimate the behavior of fresh concrete under vibration using artificial neural networks (ANNs). To this end, behavior of a full scale precast concrete mold was investigated numerically. Experimental study was carried out under vibration with the use of a computer-based data acquisition system. In this study measurements were taken at three points using two vibrators. Transducers were used to measure time-dependent lateral displacements at these points on mold while both mold is empty and full of fresh concrete. Modeling of empty and full mold was made using ANNs. Benefiting ANNs used in this study for modeling fresh concrete, mold design can be performed. For the modeling of ANNs: Experimental data were divided randomly into two parts such as training set and testing set. Training set was used for ANN's learning stage. And the remaining part was used for testing the ANNs. Finally, ANN modeling was compared with measured data. The comparisons show that the experimental data and ANN results are compatible.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.148-160
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• 2009

By the development of recent technology, a new variant of rotorcrafts having four rotors start drawing attention from aerial-robotics engineers more than before. Its potential spans from just being control device test bed to performing difficult task such as carrying surveillance device to unreachable places. In this regards, modeling a quad-rotor is significant in analyzing its dynamic behavior and in synthesizing control system for such a vehicle. This paper summarizes the modeling of a mini quad-rotor aerial vehicle. A first principle approach is considered for deriving the model based on Euler-Newton equations of motion. The result of the modeling is a simulation platform that is expected to acceptably predict the dynamic behavior of the quad-rotor in various flight conditions. Linear models associated with different flight condition can be extracted for the purpose of control synthesis.

• Coupled systems mechanics
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• v.7 no.5
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• pp.509-524
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• 2018

A hierarchical multi-scale modeling strategy devoted to the study of a Bitumen-Bound Gravel (BBG) is presented in this paper. More precisely, the paper investigates the temperature-dependent linear viscoelastic of the material when submitted to low deformations levels and moderate number of cycles. In such a hierarchical approach, 3D digital Representative Elementary Volumes are built and the outcomes at a scale (here, the sub-mesoscale) are used as input data at the next higher scale (here, the mesoscale). The viscoelastic behavior of the bituminous phases at each scale is taken into account by means of a generalized Maxwell model: the bulk part of the behavior is separated from the deviatoric one and bulk and shear moduli are expanded into Prony series. Furthermore, the viscoelastic phases are considered to be thermorheologically simple: time and temperature are not independent. This behavior is reproduced by the Williams-Landel-Ferry law. By means of the FE simulations of stress relaxation tests, the parameters of the various features of this temperature-dependent viscoelastic behavior are identified.

• Journal of the Korean Home Economics Association
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• v.50 no.1
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• pp.51-63
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• 2012

The purpose of this study was to investigate the effect of appearance management cognition on attitude toward appearance management and the effect of this attitude on appearance management behavior. It also examines how demographic factors affect these relationships. This study gave a questionnaire survey to adults between the ages of 40 and 50 in Seoul, Daegu, and Ulsan, South Korea. Data collected from 368 respondents were analyzed using descriptive statistics, t-test, factor analysis, and structural equation modeling. The study model was tested by structural equation modeling, the results of which revealed a positive effect of appearance management cognition on attitude toward appearance management and a positive effect of attitude toward appearance management on appearance management behavior. The results of t-testing showed that there were significant differences in cognition, attitude, and behavior toward appearance management by gender, age, educational level, and income.

• Structural Engineering and Mechanics
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• v.18 no.5
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• pp.691-707
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• 2004

This paper presents the micro-mechanical modeling for predicting concrete behavior under compressive loading. The model is able to represent the heterogeneities in the microstructure up to three phases, i.e., aggregate particles, matrix and interfaces. The smeared crack concept based on non-linear fracture mechanics is implemented in order to formulate the constitutive relation for each component. The splitting tensile strength is considered as a fracture criterion for cracking in micro-level. The finite element method is employed to simulate the model based on plane stress condition by using quadratic triangular elements. The validation of the model is verified by comparing with the experimental results. The influence of tensile strength from both aggregate and matrix phases on the concrete compressive strength is demonstrated. In addition, a guideline on selecting appropriate tensile strength for each phase to obtain specified concrete compressive strength is also presented.

• Fibers and Polymers
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• v.7 no.2
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• pp.123-128
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• 2006

The present study aims at characterizing and modeling the anisotropic creep behavior of coated textile membrane, a class of flexible textile composites that are used for moderate span enclosures (roofs and air-halls). The objective is to develop a creep model for predicting the lifetime of coated textile membrane. Uniaxial creep tests were conducted on three off-axis coupon specimens to obtain the directional creep compliance. A potential with three parameters is shown to be adequate for modeling the anisotropic creep behavior of coated textile membrane. Furthermore, a possibility of predicting the creep deformation of coated textile membrane in a multi-axial stress state is discussed using the three-parameter potential.

• Structural Engineering and Mechanics
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• v.51 no.5
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• pp.809-821
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• 2014

The truss based steel bridge structures usually consists of gusset plates which lose their load carrying capacity and rigidity under the effect of repeated and dynamics loads. This paper is focused on modeling the nonlinear material behavior of the gusset plates of the Truss Based Bridges subjected to dynamics loads. The nonlinear behavior of material is characterized by a damage coupled elsto-plastic material models. A truss bridge finite element model is established in Abaqus with the details of the gusset plates and their connections. The nonlinear finite element analyses are performed to calculate stress and strain states in the gusset plates under different loading conditions. The study indicates that damage initiation occurred in the plastic deformation localized region of the gusset plates where all, diagonal, horizontal and vertical, truss member met and are critical for shear type of failure due tension and compression interaction. These findings are agreed with the analytical and experimental results obtained for the stress distribution of this kind gusset plate.

• Fashion & Textile Research Journal
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• v.13 no.1
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• pp.73-81
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• 2011

The purpose of this study was to examine the effect of consumption values on well-being attitude and the effect of well-being attitude on well-being oriented behavior. This study administered a questionnaire survey to adults between 10s and 60s who lived in Seoul, Daegu, and Kyungbuk region. Data collected from 285 respondents were analyzed by descriptive statistics, t-tests, ANOVA tests, factor analyses, and structural equation modeling (SEM). The model of the study was tested by structural equation modeling and the results of SEM revealed positive effects of social value and functional value on well-being attitude and positive effect of well-being attitude on well-being oriented behavior. The results of t-tests and ANOVA tests showed that there were significant differences in consumption values, well-being attitude, and well-being oriented behavior among marital status, age, educational level, and income level groups.

• Journal of Families and Better Life
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• v.14 no.2
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• pp.241-252
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• 1996

This study was designed to analysis a causal modeling between peer acceptance of children and the related variables. The subjects were 430 5th and 6th elemantary school children. Using questionnares data on peer acceptance aggression & withdrawal behavior rated by same-sex peers and mother-child attachment were gathered,. For the statiscal analyses multiple regression and path-analysis were used. The results show social behavior that effects peer acceptance is influenced by not only aggresive behavior but also withdrawal behavior, Peer acceptance was not affected directly by mother-child attachment and paternal education while academic achievement affected peer acceptance indirectly. Therefore children's peer acceptance is mainly determined by social behavior as well as academic achievement.