• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.748-760
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• 1997

The handoff failure probability has to be enhanced efficiently to enhance the performance of PCS system. In this paper a new scheme called velocity adaptive handoff algorithm for reducing handoff failure probability and maintaining the carried traffic constantly in PCS systems, by assigning low handoff threshold value for high mobility calls, and assigning high handoff threshold value for low mobility calls, is presented. The performance of evaluation of this new scheme is carried out in terms of tranffic characteristics. Also velocity estimation algorithm for this new scheme is presented. According to the result, the handoff failure probability of velocity adaptive handoff algorithm is enhanced about 60%.

• Journal of Distribution Science
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• v.18 no.4
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• pp.5-12
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• 2020

The Purpose: This study aims to identify the characteristics of customer satisfaction of the restaurants delivery applications that is increasing globally, especially in Korea. Due to demographic changes, social trends and the development of food science, customers no longer want to visit restaurants. This represents an important change in the restaurant business, and related research is also very urgent. Research design, data, and methodology: With 296 surveyed questionnaire, the study analyzed to verify the validity and reliability of measured variables in Korea. And structural equation model was used for hypotheses test of the research. Results: The result showed that consumers' usefulness, mobility, and reliability influenced on satisfaction. Specifically, mobility and reliability influencing the satisfaction and loyalty as well. And significant impact of satisfaction and loyalty are also corroborated. However, the path from informative to both satisfaction and loyalty was not statistically significant. This means food application developers should no longer focus on providing too many information, instead, concentrate on improving mobility and trust of mobile applications. Conclusions: This study analyzed the influence of attributes of food delivery applications on satisfaction and loyalty, and suggested crucial strategic implications of delivery marketing companies involved in the implementation of mobile application developers.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.2
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• pp.111-114
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• 2008

We studied the influence of nanocrystalline silicon (nc-Si) thin film thickness on top gate nc-Si thin film transistor (TFT) fabricated at $180^{\circ}C$. The nc-Si thickness affects the characteristics of nc-Si TFT due to the nc-Si growth similar to a columnar. As the thickness of nc-Si increases from 40 nm to 200 nm, the grain size was increased from 20 nm to 40 nm. Having a large grain size, the thick nc-Si TFT surpasses the thin nc-Si TFT in terms of electrical characteristics such as field effect mobility. The channel resistance was decreased due to growth of the grain. We obtained the experimental results that the field effect mobility of the fabricated devices of which nc-Si thickness is 60, 90 and 130 nm are 26, 77 and $119\;cm^2/Vsec$, respectively. The leakage current, however, is increased from $7.2{\times}10^{-10}$ to $1.9{\times}10^{-8}\;A$ at $V_{GS}=-4.4\;V$ when the nc-Si thickness increases. It is originated from the decrease of the channel resistance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.114-130
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• 2021

With the drastic growth of Information and Communication Technology (ICT) industry, global energy consumption is exponentially increased by mobile communications. The huge energy consumption and increased environmental awareness have triggered great interests on the research of dynamic distribution of cell user and traffic, and then designing the energy efficient cellular network. In this paper, we explore the temporal and spatial characteristics of human mobility and traffic distribution using real data set. The analysis results of cell traffic illustrate the tidal effect in temporal and spatial dimensions and obvious periodic characteristics which can be used to design Base Station (BS) dynamic with sleeping or shut-down strategy. At the same time, we designed a new Cell Zooming and BS cooperation mode. Through simulation experiments, we found that running in this mode can save about 35% of energy consumption and guarantee the required quality of service.

• Structural Engineering and Mechanics
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• v.86 no.6
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• pp.751-764
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• 2023

In practical engineering such as aerial refueling pipes, the boundary of the fluid-conveying pipe is difficult to be completely immovable. Pipes under movable and immovable boundaries are controlled by different dominant nonlinear factors, where the boundary mobility will affect the nonlinear dynamic characteristics, which should be focused on for adopting different strategies for vibration suppression and control. The nonlinear dynamic instability characteristics of functionally graded fluid-conveying pipes lying on a viscoelastic foundation under movable and immovable boundary conditions are systematically studied for the first time. Nonlinear factors involving nonlinear inertia and nonlinear curvature for pipes with a movable boundary as well as tensile hardening and nonlinear curvature for pipes with an immovable boundary are comprehensively considered during the derivation of the governing equations of the principal parametric resonance. The stability boundary and amplitude-frequency bifurcation diagrams are obtained by employing the two-step perturbation- incremental harmonic balance method (TSP-IHBM). Results show that the movability of the boundary of the pipe has a great influence on the vibration amplitude, bifurcation topology, and the physical meanings of the stability boundary due to different dominant nonlinear factors. This research has guidance significance for nonlinear dynamic design of fluid-conveying pipe with avoiding in the instability regions.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.375-381
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• 2020

The purpose of this study is to observe the meaning of the movement recognized by the millennials to derive the direction of the future mobility service strategy according to the change in the mobility paradigm. To do this, the concept of mobility was understood and related cases were analyzed. The characteristics of the millennials were theoretically summarized, and an in-depth interviews were carried out with 25 Korean millennials to analyze the emotion. As a result, it was observed that mobility is not just a movement, but a movement with a pleasant experience for them, and its meaning is being extending as an experiencing good that satisfied emotions, which makes life luxurious. To establish a mobility service strategy that satisfies them First, it is necessary to make an effort to curate a mobility life suited to different emotions. Second, a strategy is required to show the language and image with emotion as a service. Third, it is necessary to play the role of an expert leading the future mobility life to be realized through connection with various fields. We expect that this study will be used as fundamental data for establishing a future mobility service strategy.

• Korean Journal of Culture and Social Issue
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• v.21 no.3
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• pp.457-479
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• 2015

This study investigated the differential effects of subjective evaluation for attention and situation adaptability, and motivation on driving mobility as a function of driver's age. The results can be summarized as followings. First, subjective capability evaluation tended to decrease as the drivers' age increased, and lower evaluation for situation adaptability seemed to be recognized earlier than attentional ability in middle-aged drivers. Second, although subjective evaluation for attentional ability predicted positively driving mobility of all age groups, but only subjective evaluation for situation adaptability predicted positively driving mobility of older drivers. Third, among motivational elements, BAS predicted positively driving mobility of young and middle-aged driviers, whereas BIS predicted positively driving mobility of older drivers. Finally, middle-aged drivers tended show increased driving mobility when their attentional ability score and BAS were high, whereas older drivers showed lowest level of driving mobility when their situation adaptability score and BIS were low. These results suggest importance of integrated consideration for drivers' subjective evaluation for attention and situation adaptability, and motivation to understand characteristics of driving mobility in different age groups.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.93-96
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• 1990

The characteristics of an inverted staggered-type hydrogenated amorphous silicon thin film transistor has been analyzed by employing numerical simulation. The field effect mobility and threshold voltage are characterized as a function of density of deep and tail states and lattice temperature. It has been found that the density of deep states plays an important role of determining the threshold voltage, while the field effect mobility are very sensitive to the slope of band tail states. Also, the numerically temperature dependence of field effect mobility and threshold voltage has been in good agreements with the experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.947-950
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• 2001

We report the characteristics of organic light emitting diodes (OLEDS) by controlling the carrier mobility according to the crystalline of Iron(II) Phthalocyanine(Fe-Pc) and metal-free Phthalocyanine (H$_2$-Pc). In order to change the recombination zone, we controlled the hole mobility by changing the crystal structures of Fe-Pc and H$_2$-Pc. OLEDs were constructed with ITO/Fe-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al and ITO/H$_2$-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al. The electroluminescent properties were changed according to the heat-treatments of Fe-Pc and H$_2$-Pc. We observed that the recombination zone and the carrier mobility were changed as the higher occupied molecular orbital levels of Fe-Pc and H$_2$-Pc decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1002-1005
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• 2002

We have synthesized novel stilbenequinone derivatives(ASQ, PSQ) and investigated the properties of their electron drift mobility. Characteristics of the ionization potential Ip and electron affinity Ea of the ASQ were investigated by determining both oxidation and reduction potentials. There were estimated Ip = 7.1 eV and Ea = 3.6 eV. The electron drift mobility of ASQ mixture(R:t-Bu 10wt%) was $1.5{\times}10^{-5}cm^2/V{\cdot}sec$ at $6.15{\times}10^{5}V/cm$ and $1.3{\mu}m$ thickness.