• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.189.1-189.1
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.73.1-73.1
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• 2008

• Applied Science and Convergence Technology
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• v.24 no.1
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• pp.22-26
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• 2015

The optical properties of InP/GaP short-period superlattice (SPS) structures grown at various temperatures from $400^{\circ}C$ to $490^{\circ}C$ have been investigated by using temperature-dependent photoluminescence (PL) and emission wavelength-dependent time-resolved PL measurements. The PL peak energy for SPS samples decreases as the growth temperature increases. The decreased PL energy of ~10 meV for the sample grown at $425^{\circ}C$ compared to that for $400^{\circ}C$-grown sample is due to the CuPt-B type ordering, while the SPS samples grown at $460^{\circ}C$ and $490^{\circ}C$ exhibit the significant reduction of the PL peak energies due to the combined effects of the formation of lateral composition modulation (LCM) and CuPt-B type ordering. The SPS samples with LCM structure show the enhanced carrier lifetime due to the spatial separation of carriers. This study represents that the bandgap energy of InP/GaP SPS structures can be controlled by varying growth temperature, leading to LCM formation and CuPt-B type ordering.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.231-236
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• 2020

In today's society, the majority of people use smartphones, and mobile ordering and payment systems for their convenience are gaining their attention. The mobile payment market is on the rise, with over 71% of the market that is already formed in China. Many mobile payment markets are growing in Korea, which is a system that is provided only in large franchises. In this paper, we propose a mobile ordering and payment system using short-range wireless communication technology that can be easily used not only in franchises but also in the small businesses, and for the convenience of users in modern society to make a system that enables ordering and payment through mobile to communicate between the devices developed by short range wireless communication technology, smartphone and the main server.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.713-716
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• 2001

In many papers, the electrochemical analysis of LiMn$_2$O$_4$shows the transition results of Mn$^{3+}$ ion. Charge ordering is accompanied by simultaneous orbital ordering due to the Jahn-Teller effect in Mnl$^{3+}$ ions. To analyze the cycle performance of LiMn$_{2-x}$Cu$_{x}$ O$_4$as the cathode of 4 V class lithium secondary batteries, XRD, TGA analysis were conducted. Although the cycle performance of the LiMn$_{2-x}$Cu$_{x}$ O$_4$was improved from pure LiMn$_2$O$_4$, the discharge capacity was significantly lower than LiCoO$_2$. In this paper, We study the Electrochemical characterization and enhanced stability of Cu-doped spinels in the LiMn$_{2-x}$Cu$_{x}$ O$_4$upon initial cycling.l cycling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.45-45
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• 2010

Nanoporous anodic alumina membranes (NAAM) with high aspect ratio, self-ordered pore array were fabricated by high-field 2-step anodization method. High voltages of 80, 100, 120 and 140 V as well as 40 V for comparison were applied to an aluminum anode with respect to a Pt cathode immersed both in 0.3M oxalic acid solution in order to investigate the self-ordering characteristics of the nanoporous structure. The pore structures, including interpore distance, pore size, pore density, and porosity as well as the ordering characteristic were analyzed using field-enhanced scanning electron microscopy (FE-SEM) and the corresponding Fourier-transformed images. The nanoporous structure could be produced for all the voltage conditions, but the well-ordered through-hole pore without a branched structure seemed to occur only at 40 and 140 V. It turned out that the growth rate under 140 V high-field anodization was about 40 times higher than under conventional 40 V mild anodization, which enabled the fast fabrication of self-ordered, high aspect ratio NAAMs.

• The Journal of Information Systems
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• v.16 no.4
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• pp.107-129
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• 2007

The purpose of this study is to examine the effect of logistics service quality and relationship orientation factors on customer satisfaction and loyalty in the electronic commerce context. Based on extensive review of relevant literature, nine components of logistics service quality(i.e. information quality, ordering procedures, ordering release quantities, timeliness, order accuracy, order quality, order condition, order discrepancy handling and personnel contact quality) and six components of relationship orientation(i.e. trust, bonding, communication, shared value, empathy and reciprocity) are introduced in this study. And a conceptual model is developed and five research hypotheses are empirically examined using structural equation modeling. The findings indicate that logistics service quality and relationship orientation are positively and significantly associated with customer satisfaction, and customer satisfaction is the antecedent variable of customer loyalty in the Internet Shopping Mall. In addition, a significant impact of logistics service quality on relationship orientation of the customer is revealed. Implications of these findings are discussed, and limitations of the study as well as further research directions are addressed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.440-448
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• 2019

In this paper, we propose an ordering chatbot that can process multiple keywords based on recursive slot-filling method. In general, in case of an order service using chatbots, the whole order process is performed only according to the sequence defined by the developer. That is, among all the information needed for the whole order process, only one input can be processed at one time. In order to reduce processing step for the order, we propose a recursive slot-filling method which fills out multiple slots per one time by extracting multiple keywords. First, a keyword array for the order is created according to the order related information. Next, from the input sentence of a user, multiple keywords is extracted. Corresponding slots for a keyword array will be filled with the extracted keywords. Finally, recursive routine will be executed to fill out all the blank in the keyword array. The usability and validity of the proposed method will be shown from the implementation of a smartphone application.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.635-641
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• 2010

Time-varying channel characteristics in OFDM systems over doubly selective channels cause inter-carrier interferences(ICI) in the frequency domain. Time domain windowing gives rise to restriction on the bandwidth of the frequency domain channel matrix and makes it possible to approximate the OFDM system as a simplified linear input-output model. When successive interference cancellation based on linear MMSE estimation is employed for channel equalization in OFDM systems, symbol detection ordering produces considerable effects on overall system performances. In this paper, we show the reduction of the residual ICI by time domain windowing and the resultant performance improvements, and investigate the effects of SINR- and CSEP-based symbol detection ordering on the performance of successive interference cancellation.

• Nuclear Engineering and Technology
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• v.37 no.3
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• pp.293-298
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• 2005

We have performed the density functional theory calculations of $UO_2$ using the spin-polarized generalized gradient approximation (SP-GGA) and the SP-GGA+U approach. The SP-GGA+U approach correctly predicts the insulating electronic structure with antiferromagnetic ordering, but the SP-GGA calculations predict metallic behavior. The cohesive properties obtained from the SP-GGA+U calculations are in good agreement with the available experimental results and previous calculations. The spin-polarized local density of states shows that the antiferromagnetic ordering of $UO_2$ is governed by 5f orbitals of uranium ion. Our calculations demonstrate that the strong correlation of U 5f electrons should be taken into account for a reliable description of $UO_2$ physics.