• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2120-2124
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• 2008

In order to rise up the accuracy of evaluation of egress safety for train car and facilities, analysis of egress route, scenario and the prediction by variation of flow rate were conducted. According to analysis of egress scenario for train, the extra time should be added to the time from train to safety area when the distance between the train car floor level and the track level exists. In the result of hand calculation, the egress time was 123.1 s at flow rate 0.5, was 61.5 s at flow rate 1.0, and was 41 s at flow rate 0.5.

• Journal of the Semiconductor & Display Technology
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• v.7 no.1
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• pp.17-22
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• 2008

The proposed hybrid controller consists of PID controller, feedforward controller and RLSE (Recursive Least Square Estimating) adaptive controller to compensate the force ripple that is periodic function of position in a linear motor. The modeling of force ripple is divided into the current-dependent and current-independent components. The current independent components never change as the current into the linear motor changes. On the other hand, the current-dependent components change as current varies when the velocity and load of the linear motor change. The proposed controller can compensate both force ripples. The feedforward controller compensates the current-independent components and the RLSE adaptive controller compensates the current-dependents components. We verified the performance of the controller by simulation and experiments.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1604-1613
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• 2018

The paper presents the equivalent circuit of an induction machine (IM) model which includes fundamental stray load and iron losses. The corresponding equivalent resistances are introduced and modeled as variable with respect to the stator frequency and flux. Their computation does not require any tests apart from those imposed by international standards, nor does it involve IM constructional details. In addition, by the convenient positioning of these resistances within the proposed equivalent circuit, the order of the conventional IM model is preserved, thus restraining the inevitable increase of the computational complexity. In this way, a compromise is achieved between the complexity of the analyzed phenomena on the one hand and the model's practicability on the other. The proposed model has been experimentally verified using four IMs of different efficiency class and rotor cage material, all rated 1.5 kW. Besides enabling a quantitative insight into the impact of the stray load and iron losses on the operation of mains-supplied and vector-controlled IMs, the proposed model offers an opportunity to develop advanced vector control algorithms since vector control is based on the fundamental harmonic component of IM variables.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.189-201
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• 2019

The purpose of this study is to identify elements of job crafting impacts on work engagement and individual work performance in Vietnamese commercial banks. The research data, collected from 226 bank officers, uses the quantitative research tools as: Cronbach's Alpha Analysis, Explanatory Factor Analysis, Confirmatory Factor Analysis as well as Structural Equation Modeling. The results of the hypothesis test show that only two hypotheses (H2, H3) are accepted: the impact of cognitive crafting on work engagement of bank officers (H2) and the impact of work engagement on individual work performance (H3). However, three remaining relationships (H1, H4, H5) are not accepted in the study: the impact of relational crafting on work engagement of bank officers (H1), the impact of relational crafting on individual work performance of bank officers (H4) and the impact of cognitive crafting on individual work performance of bank officers (H5). The study results indicate that cognition on job crafting leaves positive impacts on work engagement, leading to individual work performance enhancement. On the other hand, the relational crafting element implies contribution on neither collective nor individual working performances. Furthermore, no direct effect of cognition on job crafting to individual performance has been identified.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.451-463
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• 2019

The purpose of this study is to identify the effects of organizational conflict stages and job withdrawal intention of information security organizations. We applied Pondy's conflict theory and analyzed the case of information security workers in public enterprises. We found that the more information security workers emotionally accept the potential factors of organizational conflict, the higher the intention of job change of information security practitioner. On the other hand, the perception mechanism has a moderating effect of lowering the job change-out probability. The result of this study is expected that the manager of the organization will be able to utilize the conflict in the organizational direction.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.6
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• pp.195-206
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• 2022

The purpose of this paper is to examine how loyalty programs designed by retail stores affect customer retention. The present study is one of the few empirical studies finding the role of different loyalty programs that help to build customer retention. The study also seeks to explore the moderation role of customer perceived value between intrinsic motivation - customer retention and extrinsic motivation - customer retention. The researchers employed a quantitative research design to collect data from the 350 respondents who purchased goods from the retail chain/departmental stores in Bangladesh. The collected data are then analyzed using structural equation modeling. The result of their findings indicated that the size of the organizational reward has a positive effect on intrinsic and extrinsic motivation; further extrinsic motivation has a significant relation to customer retention. Surprisingly, no support was found for the positive impact of intrinsic motivation on customer retention. Customer perceived value (CPV) is critical as a moderator in building client retention, which improves the positive association between extrinsic motivation and customer retention. CPV, on the other hand, was found to mitigate the negative link between intrinsic motivation and client retention.

• Membrane and Water Treatment
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• v.13 no.2
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• pp.73-83
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• 2022

In the present study, we compared the adsorption capacity of Pb (II) from contaminated water of used cardboard (UC) and a commercial powdered activated carbon (PAC), the latter has been characterized by different techniques, namely X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), wavelength dispersion x-ray fluorescence (WDXRF), infrared spectroscopy (IR) and surface area B.E.T analyzer. The effect of various parameters, such as the pH, the contact time, the amount of adsorbent, and the temperature on the adsorption of Pb (II) on both materials was investigated. The Pb (II) adsorptions are perfectly described by a pseudo-second-order model, while the intraparticle diffusion is a decisive step after the first minutes of contact. The fit to the Langmuir and Redlich-Peterson models seems perfect for these adsorption reactions. (PAC) showed a greater affinity for Pb (II) compared to (UC) and the adsorption of Pb (II) ions is strongly pH-dependent, on the other hand, the increase in temperature doesn't have much influence on the two solids. This study showed that the capacity of (UC) to adsorb Pb (II) from an aqueous solution is greater than two-thirds of that of (PAC).

• The Journal of Asian Finance, Economics and Business
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• v.9 no.5
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• pp.421-429
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• 2022

Entrepreneurship research has focused on several factors that might affect the intention of an individual to start an enterprise. Using principles from social network theory and the entrepreneurial intention model (EI), the current research intends to investigate how social capital is formed on Social Networking Sites (SNS) and how the resulting social capital influences entrepreneurial intention. Using an online survey, 151 valid responses were received from university students. Applying partial least square structural equation modeling, positive and significant relationship was found between the SNS usage and bonding and bridging social capital. Further, it was also found that online-bonding social capital does not impact any of the three antecedents of entrepreneurial intention. On the other hand, online-bridging social capital significantly influences personal attitudes and subjective norms. It was also found that both personal attitude and perceived behavioral control significantly relate to EI, while the subjective norms do not relate significantly to EI. The paper contributes to the literature on technology-based human behavior and entrepreneurship in emerging countries, opening some areas for future research, while also providing some managerial insights. It also should be beneficial to educational institutions in understanding how the use of SNS use by students may be optimized.

• Economic and Environmental Geology
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• v.48 no.5
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• pp.391-400
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• 2015

Korea is a global steel producer and a major consumer while iron ore producing is very low compared to the demand. On the other hand, North Korea holds tremendous amount of iron reserves and, however, its producing rate is limited. Moreover, the data regarding mineral resources of North Korea is very limited and uncertain because of political isolation. This study estimated the amount of iron ore resource and production amount for the Musan Iron mine, the world-known open-pit mine of North Korea, using satellite imagery(Landsat MSS, ASTER) and digital maps between 1976 to 2007. As a result, the mining area of Musan mine was increased by $6.1km^2$ during the 30 years and the mining sector was estimated as $4.9km^2$. We estimated the iron resources and production amount of 0.7 and 0.2 billion metric tons, respectively based on 3D modeling and average iron ore density of Anshan formation in China. This amount indicates 8.1 million tons of annual average production and it coincides well with previous reports. We expect this study would be utilized significantly on inter-Korean exchange programs by providing trustable preliminary data.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.76-85
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• 1993

In order to predict the free surface signature of turbulent ship wakes two things are essential; a basic understanding of the mechanism of turbulent vortical flow/free surface interactions and a mathematical model to accurately predict the signature. The goal of the study described here is both to supplement experimental work to obtain basic understanding, as well as to condense this understanding in a model(or models) that captures the essential phenomena and thus allows predictions. To do so we followed two main paths guided by experimental observations. One is full simulations of the flow using the clavier-Stokes equations. The other is a vortex modeling, where the vortical structures of the flows are approximated by idealized structures, an the interaction assumed to be essentially inviscid. These approaches complement each other. Full simulations are only applicable to small scale phenomena, where the system is simple, and the Reynolds number is low. The vortex modeling, on the other hand, cannot represent essentially viscous aspects of the problem such as the effect of contamination gradient. Obviously, the modeling is what may eventually lead to a prediction method; the full simulations-too limited to mimic all but the simplest circumstances-are to aid and support the construction of realistic models. We address two-dimensional aspects of the vortex/free surface interaction first. Secondly we obtain some basic understanding of the interaction process through an experiment and then talk about several three-dimensional problems hoping to develop a successful prediction model.