• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1750-1759
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• 2018

A complete code-package for gyrotron simulation to analyze its performance is under development in UNIST, Korea. We first time report the present status of the code-package named as UNIST Gyrotron Design Tool (UGDT). It can perform design simulations for gyrotron's interaction cavity, RF window, and the essential mode calculations including the study of mode competition. We will discuss about its salient features, theory, numerical implementation, and its calculation result for 95 GHz UNIST Gyrotron. Moreover, we will validate its capability to perform the mode competition calculation for fundamental and second harmonic modes.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.114-127
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• 2016

최근 들어 글로벌 경제는 국가 간 경쟁에서 지역 기반 경쟁으로 변모하고 있다. 이 같은 변화 속에 지역공간에 기반한 지식생산과 활용이 강조되고 있다. 우리나라도 고급 과학기술인재를 양성하고 지역산업을 육성한다는 목적 하에 KAIST를 비롯한 5개 과학기술특성화대학을 대전, 대구, 광주, 포항, 울산 지역에 설립한 바 있다. 이들 과학기술특성화대학은 국내 최고 수준의 연구역량과 교육여건을 보유하고 있으며 일반대학과 비교해 우수한 연구성과를 창출하고 있다고 평가된다. 하지만 이들이 설립의 목적과는 달리 우수 연구거점으로서의 역할에 중점을 두었고, 지역혁신 거점으로서 역할은 미흡하다는 지적도 있다. 이 같은 문제의식을 바탕으로 본 연구에서는 과학기술특성화대학의 성과를 Mode 1 성과와 Mode 2 성과로 구분하고 일반대학과 비교함으로써 이들 특성화대학이 설립목적에 부합하며 동시에 지역혁신에 기여하고 있는지를 실증분석 하고자 하였다. 분석결과, 특성화대학은 Mode 1 성과에 있어 일반대학에 비해 높게 나타났으나 Mode 2 성과는 이들에 비해 오히려 낮은 것으로 나타났다. 또한 학과의 구성이나 연구 분야에 있어서도 대학별 차별성이 적고, 지역 특화산업과의 연계 정도도 낮음을 확인할 수 있었다. 결론적으로 Mode 2 관점의 지역과 연계성에 있어 분석의 대상으로 삼은 특성화대학이 일반대학에 오히려 못 미치는 성과를 보였고, 그 특성화 정도에 있어 차이점을 확인하기 어려웠다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.5-8
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• 2002

The erbium doped fibre ring laser (EDFL) is modelled using the standard propagation and rate equations of a homogeneous, two-level gain medium. The EDFL numerical simulations provide comparable results with the experimental data. The process of lasing mode competition and mode selection is clearly depicted and explained.

• 영어영문학
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• 제57권6호
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• pp.911-938
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• 2011

The present study examined the effect of two variables of task complexity, reasoning demand and time pressure, each from the resourcedirecting and resource-dispersing dimension in Robinson's (2001) framework of task classification. Reasoning demand was operationalized as the two types of texts to read and summarize, expository and argumentative. Time pressure was operationalized as the two modes of performance, oral and written. Six university students summarized the two types of text orally and twenty four students from the same school summarized them in the written form. Results from t test and ANCOVA showed that in the oral mode, reasoning demand tends to heighten the complexity of the language used in the summary in competition with accuracy but such an effect disappeared in the written mode. It was interpreted that the degree of time pressure is not the only difference between the oral and written modes but that the two modes may be fundamentally different cognitive tasks, and that Robinson's (2001) and Skehan's (1998) models were differentially supported by the oral mode of tasks but not by the written mode of the tasks.

• Journal of Information Processing Systems
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• 제17권2호
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• pp.253-270
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• 2021

In January 2013, the National Institute of Standards and Technology (NIST) announced the CAESAR (Competition for Authenticated Encryption: Security, Applicability, and Robustness) contest to identify authenticated ciphers that are suitable for a wide range of applications. A total of 57 submissions made it into the first round of the competition out of which 6 were announced as winners in March 2019. In the process of the competition, NIST realized that most of the authenticated ciphers submitted were not suitable for resource-constrained devices used as end nodes in the Internet-of-Things (IoT) platform. For that matter, the NIST Lightweight Cryptography Standardization Process was set up to identify authenticated encryption and hashing algorithms for IoT devices. The call for submissions was initiated in 2018 and in April 2019, 56 submissions made it into the first round of the competition. In August 2019, 32 out of the 56 submissions were selected for the second round which is due to end in the year 2021. This work surveys the 32 authenticated encryption schemes that made it into the second round of the NIST lightweight cryptography standardization process. The paper presents an easy-to-understand comparative overview of the recommended parameters, primitives, mode of operation, features, security parameter, and hardware/software performance of the 32 candidate algorithms. The paper goes further by discussing the challenges of the Lightweight Cryptography Standardization Process and provides some suitable recommendations.

• Journal of Communications and Networks
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• 제15권6호
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• pp.589-600
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• 2013

In this paper, we propose a new feedback scheme called mode selection-based feedback by scheduling probability prediction (SPP-MF) for channel state feedback in OFDMA downlink system. We design the scheme such that it determines the more desirable feedback mode among selective feedback by scheduling probability prediction (SPP-SF) mode and bitmap feedback by scheduling probability prediction (SPP-BF) mode, by calculating and comparing the throughputs of the two modes. In both feedback modes, each user first calculates the scheduling probability of each subchannel (i.e., the probability that a user wins the scheduling competition for a subchannel) and then forms a feedback message based on the scheduling probability. Specifically, in the SPP-SF mode, each user reports the modulation and coding scheme (MCS) levels and indices of its best S subchannels in terms of the scheduling probability. In the SPP-BF mode, each user determines its scheduling probability threshold. Then, it forms a bitmap for the subchannels according to the scheduling probability threshold and sends the bitmap along with the threshold. Numerical results reveal that the proposed SPP-MF scheme achieves significant performance gain over the existing feedback schemes.

• 한국통신학회논문지
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• 제35권5C호
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• pp.464-471
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• 2010

지속적인 네트워크 전송 능력 및 저장 매체 성능 향상에도 불구하고, 다양한 기술적 경제적 이유에서, 화질 열화를 최소화하면서 압축 성능을 증대시키기 위한 비디오 부호화 기술이 꾸준히 개발되고 있다. 본 논문에서는 종래의 비디오 성능을 더욱 향상시키기 위해, 경쟁 기반 스킵모드 부호화를 위한 적응적 문맥기반 움직임 예측 후보 선택 기법을 제안한다. 제안하는 기법은 카메라의 움직임 여부와 주변 블록의 움직임 벡터 문맥을 기반으로 움직임 예측 후보를 적응적으로 구성하여, 고정된 움직임 예측 후보를 가지는 종래의 방식에 비해 효율적인 움직임 예측 후보를 제공하였다. 이와 같이 선택된 적응적 움직임 예측 후보를, 비디오 부호기의 인터 모드 중 가장 효율적인 부호화 모드로 알려진 스킵 모드의 움직임 예측 후보 선택에 적용함으로써 종래 방식 중 가장 우수한 성능을 나타내는 경쟁 기반 움직임 벡터 부호화 방식의 BD-RATE 성능을 최대 2배까지 개선할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.101-104
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• 2005

Recently, competition between LC modes for LC TVs becomes high. In this paper, status of each mode is briefly reviewed with commenting on its electro-optic characteristics and possible application fields. Further, to understand effects of carbon nanotubes (CNTs) dispersed in nematic liquid crystal on electro-optic characteristic and orientation of the LC, CNT-doped NLC cells are made and evaluated. The hysterisis studies of voltage-dependent capacitance show that the amount of residual dc is greatly reduced due to ion trapping by CNTS.

• 한국광학회지
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• 제25권3호
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• pp.146-149
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• 2014

The homogeneous line broadening in EDF leads to unstable lasing and strong mode competition. In this paper a multiwavelength fiber ring laser that overcomes these effects by using variable attenuators between the DWDM and $1{\times}N$ coupler, has been proposed. Fiber ring lasers with four and eight wavelength outputs are implemented, and we show that the output powers can be adjusted with stable operation. The EDF ring laser has one four-wavelength output and four of single wavelengths, with OSNR of 50 and 60 dB respectively.

• 산업융합연구
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• 제2권2호
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• pp.85-99
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• 2004

Recently MNC's(multinational companies) Worldwide have been expanding their own territories in the wake of acceleration and open-door policy of global competition. So, In this study, the main goal is conduct an empirical research for MNC's contingency factors and entry modes. Through examining elements of success and limitations of foreign companies in the domestic market, a resulting purpose can be suggested such as developing attractive foreign investment policy. The results in this study are as below.