• 대한기계학회논문집A
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• 제29권2호
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• pp.325-332
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• 2005

This paper presents a study on defects in pearlite lamella structure of high carbon steel by means of finite-element method(FEM) simulation. High carbon pearlite steel wire is characterized by its nano-sized microstructure feature of alternation ferrite and cementite. FEM simulation was performed based on a suitable FE model describing the boundary conditions and the exact material behavior. Due to the lamella structure in high carbon pearlite steel wire, material plastic behavior was taken into account on deformation of ferrite and cementite. The effects of many important parameters(reduction in area, semi-die angle, lamella spacing, cementite thickness) on wire drawing process can be predicted by DEFORM-2D. It is possible to obtain the important basic data which can be guaranteed in the ductility of high carbon steel wire by using FEM simulation.

• 한국정밀공학회지
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• 제22권10호
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• pp.49-55
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• 2005

The objective of this study was presented with a prediction on the alignment of cementite in pearlite lamella structure of high carbon steel by means of finite-element method(FEM) simulation. Pearlite strcuture was characterized by its nano-sized microstructure feature of alternation ferrite and cementite. FEM simulations were performed based on a suitable FE model describing the boundary conditions and the material behavior. With the alignment of lamella structure in high carbon pearlite steel wire, material plastic behavior was taken into account on plastic deformation and alignment of cementite. The effects of many important parameters(reduction in area, semi-die angle, initial angle of cementite ) on wire drawing process were predicted by DEFORM-2D. As the results, the possibility of wire fracture could be considerably reduced and the productivity of final product could be more increased than before.

• Tribology and Lubricants
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• 제38권6호
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• pp.241-246
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• 2022

This paper presents the effects of cryogenic temperature on the wear behavior of 22MnB5 blank under cold stamping. After immersing the blank in liquid nitrogen (LN2) for 10 min, a strip drawing test was performed within 10 s. The hardness was measured using the Rockwell hardness test, which increased from 165 HV at 20℃ to 192 HV at cryogenic temperature. The strip drawing test with 22MnB5 blank and SKD61 tool steel shows that for the different wear mechanisms on the tool surface with respect to temperature; adhesive wear is dominant at 20℃, but abrasive wear is the main mechanism at cryogenic temperature. As the friction test is repeated, sticking gradually increases on the tool surface at 20℃, whereas the scratch increases at cryogenic temperature. For the friction behavior, the friction coefficient rapidly increases when adhesive wear occurs, and it occurs more frequently at 20℃. The results for nanoindentation near the worn blank surface indicate a difference of 1.3 GPa at 20℃ and 0.8 GPa at cryogenic temperature compared to the existing hardness, indicating increased deformation by friction at 20℃. This occurs because thermally activated energy available to move the dislocation decreases with decreasing temperature.

• 소성∙가공
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• 제29권2호
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• pp.89-96
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• 2020

The finite element method has been widely applied in the sheet metal forming process. However, the finite element method is computationally expensive and time consuming. In order to tackle this problem, surrogate modeling methods have been proposed. An artificial neural network (ANN) is one such surrogate model and has been well studied over the past decades. However, when it comes to ANN with two or more layers, so called deep neural networks (DNN), there is distinct a lack of research. We chose to use DNNs our surrogate model to predict the behavior of sheet metal in the deep drawing process. Thickness variation is selected as an output of the DNN in order to evaluate workpiece feasibility. Input variables of the DNN are radius of die, die corner and blank holder force. Finite element analysis was conducted to obtain data for surrogate model construction and testing. Sampling points were determined by full factorial, latin hyper cube and monte carlo methods. We investigated the performance of the DNN according to its structure, number of nodes and number of layers, then it was compared with a radial basis function surrogate model using various sampling methods and numbers. The results show that our DNN could be used as an efficient surrogate model for the deep drawing process.

• 소성∙가공
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• 제7권6호
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• pp.570-574
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• 1998

The texture evolution during deep drawing of AA1050 sheets was experimentally investigated and the lattice rotation rate was predicted using rate sensitive model with full constraints boundary conditions. The measured textures are dependent on the amount of the flange deformation and the initial crystal orientations. In the specimen parallel to RD the initial crystal orientations and the D component rotated toward the Cu component and the initial crystal orientations along the $\alpha$ fiber rotated toward the G {1 1 0}<0 0 1> and P {1 1 0} <1 1 1> components during deep drawing. In the specimen parallel to $45{\circ}$ with respect to RD the initial crystal orientations around the D component rotated about ND and the initial crystal orientations along the ${\alpha}$ fiber also rotated toward the (1 1 0) [2 3] and (1 1 0)[2 7] components about ND. In the specimen parallel to TD. the initial crystal orientations around the D component rotated toward the rotated cube and the initial crystal orientations along the ${\alpha}$ fiber rotated toward the {1 1 0} <1 1 3> component.

• 대한금속재료학회지
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• 제49권4호
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• pp.291-297
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• 2011

This work investigated the microstructure and mechanical properties of 6063 Al alloy fabricated by shear-drawing (SD) technique where shear and drawing strains were combined together within a predetermined die. To find the optimum condition for sound deformation, three different dies having different inner angle and diameter of the exit channel were prepared. After single deformation of the present sample, the sound deformation took place without an abrupt failure of the sample if the inner angle would be greater than $135^{\circ}$ in this study, when the channel diameter of the SD die was reduced from 10 to 9 mm. Microstructural observation showed that the inner angle of $135^{\circ}$ was found to be more effective than that of $150^{\circ}$ in terms of the alignment of each grain to the shear direction imposed by SD method. In addition, the yield strength of the SD-deformed sample was twice higher than that of the initial counterpart while loosing ductility in tension.

• Asia pacific journal of information systems
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• 제31권4호
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• pp.633-673
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• 2021

Due to the differences between and distinct consumer perceptions of domestic and cross-border e-commerce (CBEC), e-consumer misconduct, which we call "cunning behavior," has emerged. This study examines cunning behavior in CBEC and compares e-consumer perceptions about environmental factors and their own personal traits using a vignette experiment and survey. The vignettes of this study were developed for three situations: illegal, deviant, and unethical behavior. Drawing on vignettes, we collected survey data and then examined the research model using the analysis of moment structure statistical tool. The results show that perceived benefit and past experience with CBEC are strong triggers for cunning behavior, while the ability to exercise self-control restrains this behavior. This study provides an understanding of why cunning behavior occurs in the CBEC context and describes different cunning behavior types.

• 유통과학연구
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• 제14권1호
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• pp.75-84
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• 2016

Purpose - In accordance with the recent changes in the management environment, leaders are required to have an ability of drawing and inducing potential of each worker. Coaching, as one of the strategies of human resources development, is drawing people's attention. This study aims to inquire about the mechanism of leader's coaching behavior which influences the attitude and behavior of workers. Firstly, this study intends to illustrate what kind of influences the leader's coaching behavior can give on organizational citizenship behavior and turnover intention of workers. Secondly, it plans to verify the mediating effect of authentic leadership in the relationship between leader's coaching behavior and organizational citizenship behavior and turnover intention of workers. Thirdly, it aims to prove the moderating effect of emotional intelligence in the relationship among leader's coaching behavior, organizational citizenship behavior and turnover intention of workers. Research design, data and methodology - In order to figure out how the leader's coaching behavior influences attitude of workers, authentic leadership is considered as mediating effect. As for a moderating effect, we have determined emotional intelligence which attracts attention in the recent studies on organizational behavior, so as to investigate the correlation among variables. As for study sample, it was targeted to 236 organizational members of distribution corporations whose leader's coaching behavior is required. For reaching the purpose of study, SPSS 20 was applied for the analysis. Results - The research findings can be summarized as follows: Firstly, leader's coaching behavior gives significant positive influences on organizational citizenship behavior. Moreover, leader's coaching behavior gives negative influences on turnover intention of organizational members. Secondly, the mediating effect of authentic leadership was proved in the relationship between leader's coaching behavior and attitude of workers. Based on the analysis, it turned out that authentic leadership doesn't give a mediating effect in the bilateral relationship. Lastly, the moderating effect of emotional intelligence was proved in terms of how the leader's coaching behavior influences the attitude of workers. The research result shows that the emotional intelligence influences towards the negative direction, in the correlation between coaching behavior and organizational citizenship behavior On the other hand, in the relationship with turnover intention, It was significant effect. Conclusions - Based on the research findings, we have intended to inquired about the mechanism of leader's coaching behavior which influences the attitude and behavior of workers. Furthermore, in the operational level, the following implications can be given: the importance of coaching activation in the operational level was confirmed, through inquiring into the influence of leader's coaching behavior on workers. Moreover, the importance of emotional intelligence, which has been steadily raised, was also confirmed. It is necessary for future study to carry out additional research on various factors of coaching which can influence the effectiveness of coaching, for instance, coaching process, coach's competency, characteristics of coaching customers, relationship with coaching customers and coaching system.

• 한국생활과학회지
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• 제8권2호
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• pp.255-273
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• 1999

The purpose of this study was to examine the relationship between characteristics of personality and respondent characteristics of Kinetic Family Drawing for young children. The subjects were 170 children(110 boys and 60 girls). The personal interview contained Personality Characteristic Test for young children(In-Sub Song, 1993) and Kinetic Family Drawing Test(Burns and Kaufman, 1982). Results of the test were analyzed by t-test and ANOVA by SAS program. Results are followings. First, chileren's sex and the general tendency of personal characteristic showed significant difference in the emotional personality among 4 personality characteristics. Girls show more positive tendency than boys in moral, physical, appearance and feature which expressed personal feeling and emotion. Also, girls showed more positive tendency than boys in personal characteristic which showed physical ability. Second, Children's sex and individual characteristic in Kinetic Family Drawing respondent characteristic showed significant difference in own's arm length. Also, Using a rare of paper and chapter 1 of the power among the family showed significant difference in styles and symbols. The boys drew lengther arms compared with their height than the girls. The girls were less complicative, anxious, comparative and aggressive for their family. Third, As a result of the study about the relationship between 4 personal characteristics of children and individual's behavior in Kinetic Family Drawing respondent characteristic, the significant difference is showed in academic personality and social personality had higher completion of their father's feature and drew bigger feet. In socal personality, negative behavior than positive children. Fourth, As a result of the study about the relationship between 4 personal characteristics of children and individual's characteristic, the significant difference were found in academic personality, social personality, family personality and emotional personality. Children with negative academic personality drew longer arms than children with positive academic personality, social personality and family personality. Also, Children with negative emotional personality drew more siblings than children with positive emotional personality. Fifth, The academic personality and the social personality had significant difference in the relationship between 4 personal characteristics of children and dynamics. In social personality, normal children were more tendencious to look at the important person with their mother's direction than positive children. Sixth, In terms of the relationship between 4 personal characteristics of children and mode, academic personality and family personality showed significant difference. Children with negative academic personality used more edge of papers than children with positive academic personality and children with positive academic personality and children with negative family personality fold more papers than children with positive family personality. At last, there were no significant difference between 4 personal characteristics of children and styles as well as symbols.

• International Journal of Internet, Broadcasting and Communication
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• 제15권4호
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• pp.239-249
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• 2023

This study aims to investigate the factors influencing preventive behavior among foreigners residing in Korea. Drawing upon the Health Belief Model (HBM), this study seeks to gain insights into the decisionmaking processes underlying preventive behavior within this specific population. A comprehensive online survey was conducted among 364 foreigners. An analysis revealed that perceived barriers and perceived benefits played crucial roles as mediators, mediating the relationship between the examined factors and preventive behavior. The insights gained from this study have implications for public health interventions and self-preventive product businesses aiming to promote and sustain self-preventive behavior practices among foreigners residing in Korea, even after all COVID-19 restrictions have been lifted.