• Journal of dental hygiene science
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• v.15 no.1
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• pp.54-59
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• 2015

The present study investigated the influences of various abutment teeth shapes (maxillary right canine, pre-molar, molar) on the marginal adaptation of computer aided design/computer aided manufacturing-fabricated zirconia core. In vitro adaptation of zirconia cores manufactured by three different abutments were evaluated. Thirty zirconia cores were made per each models and the adaptation was evaluated through a silicone replica technique. The measurement of the adaptation was carried out using digital microscope. The mean and standard deviation of each reference point were analyzed using the one-way (ANOVA) and Tukey's honestly significant difference tests (${\alpha}=0.05$). The overall marginal fits of the zirconia cores were as follows: canine: $47.59{\mu}m$, pre-molar: $43.74{\mu}m$, molar: $40.36{\mu}m$. They were no statistically significant differences between groups for adaptation (p>0.05). This confirmed that the type of abutment teeth used does not determine the precision of fit of zirconia core.

• Journal of dental hygiene science
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• v.15 no.1
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• pp.12-17
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• 2015

The purpose of this study was to evaluate the marginal and internal gap of metal coping fabricated using additive manufacturing (AM) group and subtractive manufacturing (SM) group by dental computer-aided design (CAD)/computer-aided manufacturing (CAM) systems. Twenty same cases of stone models of abutment teeth 16 by the universal numbering system were manufactured and scanned. Ten metal copings of control group were fabricated using SM and ten metal coping of experimental group were fabricated using AM. Marginal and internal gap of copings were measured using the silicone replica technique and digital microscope (${\times}140$). The data were analyzed using IBM SPSS 21.0 Statistical Software for independent samples t-test (${\alpha}=0.05$). Mean${\pm}$ standard deviation (SD) of marginal and internal gap total size of SM group was $101.00{\pm}40.33{\mu}m$ of AM group was $83.61{\pm}40.37{\mu}m$. Mean${\pm}$SD of marginal and internal gap total size of SM group was significantly greater than that of AM group (p<0.05). This study showed that AM metal copings had a better marginal and internal gap than SM metal copings.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.187-199
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• 2006

This paper proposes the design of user centric pavilion information guide system based on mobile device such as PDA. which is composed of system interface factors as user wants. The suggested information guide system is convenient for user carrying because it is based on PDA mobile device and the used liquid browser system makes all data information displayed on a small screen in contrast with the other browser system. Indeed, factors of system interface can be re-composed by user interaction. And this system can effectively provide the detail information about the exhibited objects as various media data such as text, image, voice, music, video etc. The proposed system is made up of media database server. mobile system control server and mobile system interface which accepts user interaction and displays the information. Each system is networked based on TCP/IP and uses XML (extensible Markup Language) and JAVA 2 micro edition to be able to update data. This feature enhances a wide use to be able to load this system on the any mobile device.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.60-69
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• 2000

This paper describes a single-chip full-custom implementation of pipelined adaptive decision-feedback equalizer(PADFE) using a 0.25-${\mu}m$ CMOS technology for wide-band wireless digital communication systems. To enhance the throughput rate of ADFE, two pipeline stages are inserted into the critical path of the ADFE by using delayed least-mean-square(DLMS) algorithm. Redundant binary (RB) arithmetic is applied to all the data processing of the PADFE including filter taps and coefficient update blocks. When compared with conventional methods based on two's complement arithmetic, the proposed approach reduces arithmetic complexity, as well as results in a very simple complex-valued filter structure, thus suitable for VLSI implementation. The design parameters including pipeline stage, filter tap, coefficient and internal bit-width, and equalization performance such as bit error rate (BER) and convergence speed are analyzed by algorithm-level simulation using COSSAP. The single-chip PADFE contains about 205,000 transistors on an area of about $1.96\times1.35-mm^2$. Simulation results show that it can safely operate with 200-MHz clock frequency at 2.5-V supply, and its estimated power dissipation is about 890-mW. Test results show that the fabricated chip works functionally well.

• The Journal of Advanced Prosthodontics
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• v.12 no.2
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• pp.100-106
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• 2020

PURPOSE. The purpose of this in vitro study was to evaluate the fitting accuracy of single crowns made from a novel presintered Co-Cr alloy prepared with a computer-aided design and computer-aided manufacturing (CAD/CAM) technique, as compared with crowns manufactured by other digital and the conventional casting technique. Additionally, the influence of oxide layer on the fitting accuracy of specimens was tested. MATERIALS AND METHODS. A total of 40 test specimens made from Co-Cr alloy were investigated according to the fitting accuracy using a replica technique. Four different methods processing different materials were used for the manufacture of the crown copings (milling of presintered (Ceramill Sintron-group_cer_sin) or rigid alloy (Tizian NEM-group_ti_nem), selective laser melting (Ceramill NPL-group_cer_npl), and casting (Girobond NB-group_gir_nb)). The specimens were adapted to a resin model and the outer surfaces were airborne-particle abraded with aluminum oxide. After the veneering process, the fitting accuracy (absolute marginal discrepancy and internal gap) was evaluated by the replica technique in 2 steps, before removing the oxide layer from the intaglio surface of the crowns, and after removing the layer with aluminum oxide airborne-particle abrasion. Statistical analysis was performed by multifactorial analysis of variance (ANOVA) (α=.05). RESULTS. Mean absolute marginal discrepancy ranged between 20 ㎛ (group_cer_npl for specimens of Ceramill NPL) and 43 ㎛ (group_cer_sin for crowns of Ceramill Sintron) with the oxide layer and between 19 ㎛ and 28 ㎛ without the oxide layer. The internal gap varied between 33 ㎛ (group_ti_nem for test samples of Tizian NEM) and 75 ㎛ (group_gir_nb for the base material Girobond NB) with the oxide layer and between 30 ㎛ and 76 ㎛ without the oxide layer. The absolute marginal discrepancy and the internal gap were significantly influenced by the fabrication method used (P<.05). CONCLUSION. Different manufacturing techniques had a significant influence on the fitting accuracy of single crowns made from Co-Cr alloys. However, all tested crowns showed a clinically acceptable absolute marginal discrepancy and internal gap with and without oxide layer and could be recommended under clinical considerations. Especially, the new system Ceramill Sintron showed acceptable values of fitting accuracy so it can be suggested in routine clinical work.

• Journal of Korea Game Society
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• v.9 no.3
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• pp.23-33
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• 2009

This study aims to uncover the gamers' cognitive process during the gameplay and explore the differences between groups in the gamers' playing behavior according to their expertise: experts, intermediate players, and novices. To this end, the empirical experiment was conducted in 'World of Warcraft' game which is a good representative of MMO(Massively Multi-player Online) game currently. Verbal protocol and action protocol collected from the empirical experiment were analyzed according to the gamers' expertise. As a result of this study, we found that the different behavior patterns result from standardizing pattern of their actions for experts and forming the learning curves and the specific patterns of action for intermediate game players and novices. While three functional-actions as a collection action concentrates on the early stage of the game for experts, the novices' behavior pattern dispersedly appeared in all seven functional-action, such as search, combat, three type collections, avoid, and communication in the whole gameplay. This study represents the consistency and the difference derived from the comparison analysis between groups according to the expertise. This study is concluded with key implications to support game design guidelines according to experts, intermediate players, and novices. Consequently, the result of this study provides the basic to the development of MMO content for game novices.

• Journal of The Korean Association For Science Education
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• v.36 no.3
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• pp.499-507
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• 2016

A flipped learning class was held in an attempt to overcome the limits of lecture-type classes in pre-service science teacher training and to provide a student-oriented education suitable for digital native generation. The principles of teaching-learning in flipped learning were applied to the general ADDIE model to design the class; learning materials were developed accordingly. The developed flipped learning materials and class design were verified for their validity using an expert panel's Delphi method and validity test, in which the validity was verified with 0.75 CVR. The developed flipped learning materials were applied to the theory of science education and the instructional effectiveness was analyzed. The results suggest that the students' motivation to study, interest, and confidence in learning increased; however, their satisfaction in class decreased by 30% as compared to the lecture-type class and their self-confidence in the improvement of their academic achievement was not sufficient. In order for a flipped learning class to be successful, the class should be small in size, which would ensure appropriate teacher-student communication and individualized learning; also, the students' burden of learning should be reduced and accessibility to video materials for pre-class learning should be reinforced.

• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.195-202
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• 2004

This paper introduces the design or parallel Pipeline high-speed analog-to-digital converter(ADC) for the high-resolution video applications which require very precise sampling. The overall architecture of the ADC consists of 4-channel parallel time-interleaved 10-bit pipeline ADC structure a]lowing 200MSample/s sampling speed which corresponds to 4-times improvement in sampling speed per channel. Key building blocks are composed of the front-end sample-and-hold amplifier(SHA), the dynamic comparator and the 2-stage full differential operational amplifier. The 1-bit DAC, comparator and gain-2 amplifier are used internally in each stage and they were integrated into single switched capacitor architecture allowing high speed operation as well as low power consumption. In this work, the gain of operational amplifier was enhanced significantly using negative resistance element. In the ADC, a delay line Is designed for each stage using D-flip flops to align the bit signals and minimize the timing error in the conversion. The converter has the power dissipation of 280㎽ at 3.3V power supply. Measured performance includes DNL and INL of +0.7/-0.6LSB, +0.9/-0.3LSB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2109-2116
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• 2014

This paper presents the implementation and design of the advanced WI-FI systems with beam-forming antenna that radiate their power to the direction of user equipment to improve the overall throughput, contrast to the general WI-FI systems equipped with omni-antenna. The system consists of patch array antenna, DSP, FPGA, and Qualcomm's commercial chip. The beam-forming system on the FPGA utilizes the packet information from Qualcomm's commercial chip to control the phase shifters and attenuators of the patch array antenna. The PCI express interface has been used to maximize the communication speed between DSP and FPGA. The directions of arrival of users are managed using the database, and each user is distinguished by the MAC address given from the packet information. When the system wants to transmit a packet to one user, it forms beams to the direction of arrival of the corresponding user stored in the database to maximize the throughput. Directions of arrival of users are estimated using the received preamble in the packet to make its SINR as high as possible. The proposed beam-forming system was implemented using an FPGA and Qualcommm's commercial chip together. The implemented system showed considerable throughput improvement over the existing general AP system with omni-directional antenna in the multi-user communication environment.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.29-36
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• 2012

This study aims to analyse the research trend of the participants in Emotional Science in Korea and to suggest a desirable direction of research. I analysed the 1,262 articles published in Korean Journal of the Science of Emotion and Sensibility from 2000 to 2011 according to fields of study and keywords. The findings from the study are as follows. In the fields of study regarding Clothing Design, Psychology, Medicine, Visual Media, Brain Science they are still the top rated categories amongst participants. With the participation of Industrial Engineering and Ergonomics they have shown a meaningful difference depending on governmental support such as G7 Project. The problem with Industrial Design is that the majority of studies have been performed alone, and they have many keywords which are not related with Emotional Science. However, 31 new fields of study have been added to the research making the findings more desirable considering that Emotional Science is typical interdisciplinary filed of study. I hope that this study will provide basic data which can be used to promote the interdisciplinary research between the different fields of study in order to generate significant synergy.