• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.77-83
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• 2016

International standards for systems safety have been established in various areas of industry. Such standards recommend that safety design activities be carried out early on in the beginning of systems development. Hazard analysis should be done in close interaction with the conceptual design of the system. This paper focuses on how to verify whether the safety goals are met while considering system design issues. The architecture of the underlying system was first modeled using SysML, a systems modeling language, and then hazard analysis was performed based on architectural information to obtain a system failure model. Thereafter, an integrated model was developed by combining the SysML failure model and the architectural model, and then safety designs were added to prevent system failure. Finally, a simulation of the developed model was performed to see if a system functions even when some components are failing.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.368-372
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• 2016

In this study, we develop a novel high-throughput micronanopatterning system that can implement continuous mechanical pattern inscribing on flexible substrates using a rigid grating mold edge. We perform a conceptual design of the process principle, specific modeling, and buildup of a real system prototype. This research also carefully addresses several important issues related to processing and controlling, including precision motion, alignment, heating, and sensing to enable a successful micronanopatterning in a continuous and high-speed fashion. Various micronanopatterns with the desired profiles can be created by tuning the mold shape, temperature, force, and substrate material toward many potential applications involving electronics, photonics, displays, light sources, and sensors, which typically require a large-area and flexible configurations.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.231-238
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• 2005

On the basis of flow resistance theory the conceptual model and related mathematical descriptions is proposed for resistance modeling of groundwater flow in CPM(continuum Porous medium), DFN(discrete fracture network) and fractured-porous medium. The proposed model is developed on the basis of finite volume method assuming steady-state, constant density groundwater flow. The basic approach of the method is to evaluate inter-block flow resistance values for a staggered grid arrangement, i.e. fluxes are stored at cell walls and scalars at cell centers. The balance of forces, i.e. the Darcy law, is utilized for each control volume centered around the point where the velocity component is stored. The transmissivity (or permeability) at the interface is assumed to be the harmonic average of neighboring blocks. Flow resistance theory was utilized to relate the fluxes between the grid blocks with residual pressures. The flow within porous medium is described by three dimensional equations and that within an individual fracture is described by a two dimensional equivalent of the flow equations for a porous medium. Newly proposed models would contribute to develop flow simulation techniques with various matrix characteristics.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.201-207
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• 2004

Dissolved air flotation (DAF) is a solid-liquid separation process that uses fine rising bubbles to remove particles in water. Most of particle-bubble collision occurs in the DAF contact zone. This initial contact considered by the researchers to play a important role for DAF performance. It is hard to make up conceptual model through simple mass balance for estimating collision efficiency in the contact zone because coupled behavior of the solid-liquid-gas phase in DAF system is 90 complicate. In this study, 2-phase(gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using an Eulerian-Eulerian approach based on the assumption that very small particle is applied in the DAF system. For the modeling of turbulent 2-phase flow in the reactor, the standard $k-{\varepsilon}$ mode I(liquid phase) and zero-equation(gas phase) were used in CFD code because it is widely accepted and the coefficients for the model are well established. Particle-bubble collision efficiency was calculated using predicted turbulent energy dissipation rate and gas volume fraction. As the result of this study, the authors concluded that bubble size and recycle ratio play important role for flow pattern change in the reactor. Predicted collision efficiency using CFD showed good agreement with measured removal efficiency in the contact zone. Also, simulation results indicated that collision efficiency at 15% recycle ratio is higher than that of 10% and showed increasing tendency of the collision efficiency according to the decrease of the bubble size.

• Culinary science and hospitality research
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• v.23 no.7
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• pp.194-203
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• 2017

The data collection and questionnaire survey were conducted from July 1, 2016, to August 30, 2016, and the final analysis was conducted with 273 copies. The collected data were analyzed using SPSS (V 23.0) and AMOS (V 21.0) programs. In order to identify the characteristics of the respondents, the frequency analysis was performed, and the reliability analysis and confirmatory factor analysis were performed for each measurement item. The conceptual reliability (CR) and standard variance extraction (AVE) values were calculated to verify the validity. Correlation analysis was conducted to measure the associations among the derived factors. For the hypothesis test, a structural equation modeling was used to test the jointness and organic causality of the whole model. In addition, an alternative model with a nested relationship with the basic model was set up to test the adjustment effect of the learner's educational environment on the educational satisfaction and behavioral intention. The purpose of the study was to examine the effect of educational environment on the educational satisfaction and behavioral intention of students at a cooking education institute in Busan. The implication of this study is that the operators of educational institutions should recognize the human factors as important means of marketing for the activation of cooking education and select instructors by applying more systematic and objective criteria when hiring instructors. Also, consideration should be given to support programs such as training programs and incentives to develop instructor's abilities. In addition, the positive educational outcomes of students may have a positive impact on financial performance, such as livelihood of other students and sales of educational institutions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1828-1835
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• 2012

In this paper, a conceptual design and a detailed design of novel cylindrical magnetic levitation stage is introduced. This is came from planar-typed magnetic levitation stage. The proposed stage is composed of cylinder-typed permanent magnet array and semi-cylinder-typed 3 phase winding module. When a proper current is induced at winding module, a magnetic levitation force between the permanent magnet array and winding module is generated. The proposed stage can precisely move the cylinder to rotations and translations as well as levitations with the magnetic levitation force. This advantage is useful to make a nano patterning on the surface of cylindrical specimen by using electron beam lithography under vacuum. Two methods are used to calculate required magnetic levitation forces. The one is 2D FEM analysis, the other is mathematical modeling. This paper shown that results of two methods are similar. An assistant plate is introduced to reduce required currents of winding module for levitations in vacuum. The mathematical model of cylindrical magnetic levitation stage is used for dynamic simulation of magnetic levitations. A lead-lag compensator is used for control of the model. Simulation results shown that the detail designed model of the cylindrical magnetic levitation stage with the assistant plate can be controlled very well.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.907-914
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• 2010

Cognitive model, that is cognitive architecture, is the model expressed with computer program to show the process how human solve a certain problem and it is continuously under investigation through various fields of study such as cognitive engineering, computer engineering, and cognitive psychology. In addition, the much extensive applicability of cognitive model usually helps it to be used for quantitative prediction of human Behavior or Natural programming of human performance in many HCI areas including User Interface Usability, artificial intelligence, natural programming language and also Robot engineering. Meanwhile, when a system designed, an usability test about conceptual design of interface is needed and in this case, analysis evaluation using cognitive model like GOMS or ACT-R is much more effective than empirical evaluation which naturally needs products and subjects. In particular, if we consider the recent trend of very short-end term between a previous technology development and the next new one, it would take time and much efforts to choose subjects and train them in order to conduct usability test which is repeatedly followed in the process of a system development and this finally would bring delays of development of a new system. In this study, we predicted quantitatively the human behavior processes which contains cognitive processes for menu selection in touch screen interface through ACT-R, one of the common method of usability test. Throughout the study, it was shown that the result using cognitive model was equal with the result using existing empirical evaluation. And it is expected that cognitive model has a possibility not only to be used as an effective methodology for evaluation of HCI products or system but also to contribute the activation of HCI cognitive modeling in Korea.

• The Journal of Information Systems
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• v.29 no.2
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• pp.95-110
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• 2020

Purpose This paper attempts to explain the recent expanding trend in Mobile Grocery Shopping(MGS). More specifically, the authors have applied the Post Acceptance Model(PAM) in order to examine the conceptual structure among the four constructs of 'Expectation Confirmation', 'Perceived Usefulness', 'User Satisfaction', and 'Continuance Intention to Use' in Mobile Grocery Shopping. Design/methodology/approach Through a survey agency, data were collected from a sample of 312 consumers who had the previous experience in Mobile Grocery Shopping. The Structural Equation Modeling(SEM) analysis was conducted with the survey data using AMOS 22.0. Subsequently, 8,200 real customer data from an open market site were collected in order to find out their revisit and repurchase behavior. Findings This study supported the causal relationships of Expectation Confirmation → Perceived Usefulness, Expectation Confirmation → User Satisfaction, Perceived Usefulness → User Satisfaction, and User Satisfaction → Continuance Intention to Use, but did not support the direct effect of Perceived Usefulness on the Continuance Intention to Use Mobile Grocery Shopping. This implies that consumers with any experience in Mobile Grocery Shopping would not consider repurchase, unless they are satisfied with the experience even though they perceive its usefulness. Also, Expectation Confirmation has much larger effect on User Satisfaction than Perceived Usefulness. In addition, the real customer data showed that the revisit and the repurchase rate of mobile grocery shoppers were higher than those of online grocery shoppers, although the rates of adding to shopping carts, coupon downloads, and adding to favorites are similar.

• Korean Business Review
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• v.17 no.2
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• pp.131-159
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• 2004

The purpose of this paper is to propose and test a conceptual framework that investigates the effects of perceived service quality on customer satisfaction, attitude toward brand(Ab) and customer loyalty. To test the framework, structural equation modeling are applied to data collected from 210 samples in mobile phone service industry. The results of this research indicated that interaction quality and outcome quality of perceived service quality are positively on customer satisfaction, but the outcome quality is stronger influence than interaction quality. The findings also show that outcome quality effect on directly Ab and then interaction quality effect on indirectly Ab through customer satisfaction. But There are no effect outcome quality, interaction quality and Ab on customer loyalty without customer satisfaction effect. These results include implications that mobile phone service company should have customer satisfaction to retain customer and customer loyalty.

• Journal of Korean Academy of Nursing
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• v.48 no.5
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• pp.534-544
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• 2018

Purpose: This study was conducted to construct and test a structural model on family life satisfaction of aged individuals living at home. The conceptual model was based on Bandura's self-efficacy and social cognitive theories (1977; 1986) and Bowen's (1976) family systems theory. Methods: From January 25 to March 5, 2016, 227 older adults living at home completed a structured questionnaire. Data were analyzed to calculate the direct and indirect effects of factors affecting family life satisfaction. SPSS WIN 20.0 and AMOS 20.0 were used. Results: The hypothetical model was a good fit for the data. The model fit indices were ${\chi}^2=78.05$, ${\chi}^2/df=1.35$, RMSR=.02, GFI=.98, AGFI=.96, NFI=.94, CFI=.98, and RMSEA=.05. Family life satisfaction was positively affected by perceived collective family efficacy, status of physical health, family communication, and family support. Depression resulted in a significant negative effect. Family differentiation had a significant indirect effect on family life satisfaction. The model explained 76% of variance in family life satisfaction. Conclusion: Perceived collective family efficacy, status of physical health, depression, family differentiation, family communication, and family support were significant factors explaining family life satisfaction among older adults staying at home. Further research should be conducted to seek intervention strategies to improve family life satisfaction among older adults living at home by focusing on the respective contributing factors.