• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.70.3-70.3
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• 2015

After a short description of the telescope, we will report on the recent developments in three main areas: - Commissioning of the last of LBT's first generation instruments, now well underway, - Adaptive Optics (AO) and ground-layer AO progress and planned upgrades, - Interferometry first science results. We will also explore the future of the facility as it moves to full operation and strive to be the first of the ELTs in the decade-long window in which GMT, TMT, and E-ELT break ground and start taking shape.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.17-23
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• 2016

LTE Licensed-Assisted Access(LAA)는 3GPP에서 진행되고 있는 비면허대역을 활용하여 LTE 시스템을 동작시키는 표준기술이다. LTE-LAA의 필요성과 표준의 진화 과정을 알아보고, Listen-Before-Talk(LBT) 등 핵심 표준기술들을 소개하였고, 특히, WiFi 등 기존의 비면허대역에서 동작하는 시스템과의 공정한 공존(fair coexistence)를 위해 어떠한 노력이 이루어졌는지를 중점적으로 살펴보았다. 마지막으로, 현재 3GPP 표준에서 논의되는 enhanced LAA를 통해 비면허대역을 활용하는 LTE 시스템 기술의 진화를 전망해 보았다.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.186.1-186
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• 2003

• Journal of Korean Clinical Health Science
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• v.1 no.1
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• pp.75-82
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• 2013

Purpose : The aim of this study was to identify the relation of cognition and visuospatial perception in stoke patients. Methods : A total of 16 stroke patients recruited from two hospital located in Donghae, Kang-won participated in this study(Right hemiplegia : twelve, Left hemiplegia : four). All participants scored higher than 20 point on the MMSE-K. To assess the cognitive function, we performed the Korean version of Mini Mental State Examination(MMSE-K), spatial perception domain of Lowenstein Occupational Therapy Cognition Assessment(LOTCA), Figure Color Copy(FCC), Linebisection Test(LBT) and Albert's test in stoke patients. Results: The Korean version of Mini Mental State Examination and spatial perception domain of Lowenstein Occupational Therapy Cognition Assessment were the highest points in sixty ages, Figure Color Copy is difference between Right hemiplegia and Left hemiplegia. Linebisection Test(LBT) and Albert's test had much relation, visuospatial perception had not relationship. Conclusion: Aging was cognition function and visuospatial perception had an interrelationship. visuospatial perception according to affected side in brain had an interrelationship but cognition function and visuospatial perception had not any interrelationship.

• The korean journal of orthodontics
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• v.48 no.6
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• pp.367-376
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• 2018

Objective: This study was performed to investigate the changes in alveolar bone after maxillary incisor intrusion and to determine the related factors in deep-bite patients. Methods: Fifty maxillary central incisors of 25 patients were evaluated retrospectively. The maxillary incisors in Group I (12 patients; mean age, $16.51{\pm}1.32years$) were intruded with a base-arch, while those in Group II (13 patients; mean age, $17.47{\pm}2.71years$) were intruded with miniscrews. Changes in the alveolar envelope were assessed using pre-intrusion and post-intrusion cone-beam computed tomography images. Labial, palatal, and total bone thicknesses were evaluated at the crestal (3 mm), midroot (6 mm), and apical (9 mm) levels. Buccal and palatal alveolar crestal height, buccal bone height, and the prevalence of dehiscence were evaluated. Two-way repeated measure ANOVA was used to determine the significance of the changes. Pearson's correlation coefficient analysis was performed to assess the relationship between dental and alveolar bone measurement changes. Results: Upper incisor inclination and intrusion changes were significantly greater in Group II than in Group I. With treatment, the alveolar bone thickness at the labial bone thickness (LBT, 3 and 6 mm) decreased significantly in Group II (p < 0.001) as compared to Group I. The LBT change at 3 mm was strongly and positively correlated with the amount of upper incisor intrusion (r = 0.539; p = 0.005). Conclusions: Change in the labial inclination and the amount of intrusion should be considered during upper incisor intrusion, as these factors increase the risk of alveolar bone loss.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.138-138
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• 2003

Low temperature co-fired ceramic (LTCC) technology offers significant benefits over the other established packaging technologies for high density, high microwave frequency, and fast signal application. Most conventional electroceraramics do not meet the basic requirements in respect of sinterability for LTCC technology. Attention is, therefore, focused on the role of glasses because of the capability they supply with lower sintering temperatures. In this study, commercial ceramic (MBRT-90) in the system BaO-N $d_2$ $O_3$-Ti $O_2$ (BNT: 40 ~ 80 wt%) and L $a_2$ $O_3$- $B_2$ $O_3$-Ti $O_2$ glass (LBT;60 ~ 20 wt%) were prepared. These glass/ceramic composites were evaluated for sintering behavior, phase evaluation, densities, interface reaction, crystallinity, microstructure and microwave dielectric properties. It was found that the addition LBT glass frits significantly lowered the sintering temperature to below 90$0^{\circ}C$ and as temperature increased (750~90$0^{\circ}C$) densification developed dynamically which was meant to be as over 95% of relative density. It is supposed that in the microstructure, the grain size was increased accompanying with the formation of different phases such as LaB $O_3$ and Ti $O_2$ under the condition of increasing sintering temperature. The sintered bodies represented applicable dielectric properties, namely 20 ~ 40 for $\varepsilon_{{\gamma}}$, ~ 10000 GHz for Q* $f_{0}$ and 10~80 ppm/$^{\circ}C$ for $\tau$$_{f}$. The results suggest that the composite is one of feasible candidates for the microwave use in LTCC technology.y.e use in LTCC technology.y.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.58-64
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• 2008

In this paper, we proposed the methodology of interference analysis based on monte-carlo method for effective use of Industrial, Scientific, Medical (ISM) band. The interference scenario is divided according to the distance and density. The simulation of interference analysis evaluates the interference probability according to distribution density of Interfering Transmitters (It) in the Secure Interference Area (SIA). The SIA is gained from the Interference Efficiency Range that satisfied to Interference Permissible Range of Victim Receiver (Vr). Simulation result that apply the proposed interference scenario to the WLAN and bluetooth, Interference Permissible Range was 60~400m. And the WLAN was acceptable within interference permissible range to six bluetooth that exist in the SIA. In the same condition, when applied Listen Before Talk (LBT) based on Cognitive Radio (CR) to the bluetooth using Frequency Hopping (FH), interference probability was decreased sharply. The Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) that has been developed based on the monte-carlo method by European Radio-communications Office (ERO) were used to the interference simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.33-41
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• 2008

As RFID technology is developing and increasingly being used in many applications, the implementation is changing from single reader to multiple readers even dense readers. Since the number of readers is increasing, there are more collisions between readers and much interference between readers and tags. Therefore, to avoid interference or collision, many algorithms have being proposed, such as Gen2 dense mode, LBT(listen before talk), TDMA based method. In this paper, we propose a null frame algorithm, which calculates the collision probability in frame slotted aloha scheme and use this information to avoid the possible collisions. Comparing with conventional scheme, our proposed algorithm has some advantages in terms of reader collision number and required frame numbers.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.9-18
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• 2006

This paper presents a Monte-Carlo based method to obtain a probability of interference in the 900MHz passive RFID systems. We show an efficient algorithm to calculate not only in-band interference due to unwanted emission of interfering sources for a given emission mask, but out-of-band interference, which depends on the blocking performances of a victim receiver filter. We next apply the proposed method to two types of RFID systems, one is to use simple FHSS and the other to adopt a hybrid use of FHSS and LBT, which senses the channel before transmission. Simulation is first performed with a SEAMCAT. We next make simulation with a MATLAB software which implements SEAMCAT algorithm and show both results from two softwares are similar.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1442-1444
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• 2001

A new low-temperature poly-Si TFT employing a counter-doped lateral body terminal is proposed and fabricated, in order to enhance the stability of poly-Si TFT driving circuits. The LBT structure effectively suppresses the kink effect by collecting the counter-polarity carriers and suppresses the hot carrier effect by reducing the peak lateral field at the drain junction. The proposed device is immune to dynamic stress, so that it is suitable for low voltage and high speed driving circuits of AMLCD.