• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.61.1-61.1
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• 2015

Nanoscale semiconductor plasma processing has become one of the most challenging issues due to the limits of physicochemical fabrication routes with its inherent complexity. The mission of future and emerging plasma processing for development of next generation semiconductor processing is to achieve the ideal nanostructures without abnormal profiles and damages, such as 3D NAND cell array with ultra-high aspect ratio, cylinder capacitors, shallow trench isolation, and 3D logic devices. In spite of significant contributions of research frontiers, these processes are still unveiled due to their inherent complexity of physicochemical behaviors, and gaps in academic research prevent their predictable simulation. To overcome these issues, a Korean plasma consortium began in 2009 with the principal aim to develop a realistic and ultrafast 3D topography simulator of semiconductor plasma processing coupled with zero-D bulk plasma models. In this work, aspects of this computational tool are introduced. The simulator was composed of a multiple 3D level-set based moving algorithm, zero-D bulk plasma module including pulsed plasma processing, a 3D ballistic transport module, and a surface reaction module. The main rate coefficients in bulk and surface reaction models were extracted by molecular simulations or fitting experimental data from several diagnostic tools in an inductively coupled fluorocarbon plasma system. Furthermore, it is well known that realistic ballistic transport is a simulation bottleneck due to the brute-force computation required. In this work, effective parallel computing using graphics processing units was applied to improve the computational performance drastically, so that computer-aided design of these processes is possible due to drastically reduced computational time. Finally, it is demonstrated that 3D feature profile simulations coupled with bulk plasma models can lead to better understanding of abnormal behaviors, such as necking, bowing, etch stops and twisting during high aspect ratio contact hole etch.

• 정보교육학회논문지
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• 제22권6호
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• pp.661-669
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• 2018

2015 개정교육과정에 의해 2018년부터 SW 교육이 필수화되면서 SW 교육에 대한 연구가 활발하게 이루어지고 있다. 본 논문에서는 예비교사들의 컴퓨팅 사고력 수준을 파악하기 위해 2016년부터 2018년까지 3년 동안 K 교육대학교 1학년 학생 325명을 대상으로 스크래치 수업을 실시한 후 연도별로 산출된 스크래치 프로젝트를 Dr. Scratch 분석도구로 평가하여 연도별과 학점별로 CT요소 점수의 연관성을 분석하였다. 그 결과, 연도와 학점이 높을수록 CT요소, 점수, 등급도 높아짐을 알 수 있었다. 이를 통해, 학생들은 Dr. Scratch와 같은 자동화된 평가도구를 사용하여 평가해 본 후 스스로 수정 보완해보는 과정과 필요한 자료를 직접 제작하여 활용하는 ICT 능력이 필요하며, 복잡한 조건과 논리연산 활용 등 논리적 사고 요소를 이해하고 잘 활용될 수 있도록 교육될 필요가 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1168-1172
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• 2004

This paper presents a speed controller based on an adaptive fuzzy algorithm for high performance permanent magnet synchronous motor (PMSM) drives under parameter and load variations. In many speed tracking control systems PI controller has been used due to its simple structure and easy of design. PI controller, however, suffers from the electrical machine parameter variations and disturbances. In order to improve the tracking control performance under load variations, the PI controller parameters are modified during operation by adaptive fuzzy method. This method based on optimal fuzzy logic system has simple structure and computational simplicity. It needs only sample data which is obtained by optimal controller off-line. As the sample data implemented in the adaptive fuzzy system can be modified or extended, a flexible control system can be obtained. Simulation results show the usefulness of the proposed controller.

• 대한임베디드공학회논문지
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• 제7권2호
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• pp.79-84
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• 2012

Efficient arithmetic design is essential to implement error correcting codes and cryptographic applications over finite fields. This article presents an efficient $AB^2$ multiplier in GF($2^m$) using a polynomial representation. The proposed multiplier produces the result in m clock cycles with a propagation delay of two AND gates and two XOR gates using O($2^m$) area-time complexity. The proposed multiplier is highly modular, and consists of regular blocks of AND and XOR logic gates. Especially, exponentiation, inversion, and division are more efficiently implemented by applying $AB^2$ multiplication repeatedly rather than AB multiplication. As compared to related works, the proposed multiplier has lower area-time complexity, computational delay, and execution time and is well suited to VLSI implementation.

• 대한기계학회논문집A
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• 제21권3호
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• pp.361-368
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• 1997

In order to eliminate position errors existing at the steady state in the motion control of robotic manipulators, a new fuzzy control algorithm is propeosed using three variables, position error, velocity error and integral of position errors as input variables of the fuzzy controller. Although the number of input variables of the fuzzy controller is increased from two to three, the number of fuzzy control rules is just increased by two. Three dimensional look-up table is used to reduce the computational time in real-time control, and a technique reducing the amount of necessary memory is introduced. Simulation and experimental studies show that the position errors at the steady state are decreased more than 90% compared to those of existing fuzzy controller when the proposed fuzzy controller is applied to the 2 axis direct drive SCARA robot manipulator.

• 한국언어정보학회:학술대회논문집
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• 한국언어정보학회 2002년도 Language, Information, and Computation Proceedings of The 16th Pacific Asia Conference
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• pp.1-1
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• 2002

This talk provides an overview of current work in my research group on the syntactic annotation of the T bingen corpus of spoken German and of the German Reference Corpus (Deutsches Referenzkorpus: DEREKO) of written texts. Morpho-syntactic and syntactic annotation as well as annotation of function-argument structure for these corpora is performed automatically by a hybrid architecture that combines robust symbolic parsing with finite-state methods ("chunk parsing" in the sense Abney) with memory-based parsing (in the sense of Daelemans). The resulting robust annotations can be used by theoretical linguists, who lire interested in large-scale, empirical data, and by computational linguists, who are in need of training material for a wide range of language technology applications. To aid retrieval of annotated trees from the treebank, a query tool VIQTORYA with a graphical user interface and a logic-based query language has been developed. VIQTORYA allows users to query the treebanks for linguistic structures at the word level, at the level of individual phrases, and at the clausal level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.182-184
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• 2004

This paper presents a PI controller tuning method for high performance permanent magnet synchronous motor (PMSM) drives under load variations using clustering fuzzy algorithm. In many speed tracking control systems PI controller has been used due to its simple structure and easy of design. PI controller, however, suffers from the electrical machine parameter variations and disturbances. In order to improve the tracking control performance under load variations, the PI controller parameters are modified during operation by clustering fuzzy method. This method based on optimal fuzzy logic system has simple structure and computational simplicity. It needs only sample data which is obtained by optimal controller off-line. As the sample data implemented in the adaptive fuzzy system can be modified or extended, a flexible control system can be obtained Simulation results show the usefulness of the proposed controller.

• 경영과학
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• 제28권1호
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• pp.117-127
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• 2011

In the Multi-Echelon maintenance environment, METRIC(Multi-Echelon Technique for Repairable Item Control) has been used in several different inventory level selection models, such as MOD-METRIC, Vari-METRIC, and Dyna- ETRIC. While this model's logic is easy to be implemented, a critical assumption of infinite maintenance capacity would deteriorate actual values, especially Expected Back Order(EBO)s for each item. To improve the accuracy of EBO, we develop two models using simulation and queueing theory that calculates EBO considering finite capacity. The result of our numerical example shows that the expected backorder from our model is much closer to the true value than the one from Vari-METRIC. The queueing model is preferable to the simulation model regarding the computational time.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.847-851
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• 2007

Finite automata는 실제 복잡한 컴퓨터의 연산을 수학적으로 모델링하는 computational 모델 중 하나로써 작은 메모리를 가지는 컴퓨터를 모델링하기에 적합하다. 이는 유비쿼터스 환경에서 실제로 작은 메모리를 가지는 장치가 ECA 룰을 작동시키는 디바이스 로직(디바이스 logic)을 효과적으로 운영할 수 있는지 여부를 검증하는 도구로 사용될 수 있다. 본 논문은 웹서비스 기반의 이벤트 처리 언어를 CFA로 모델링하고 알고리즘을 개발하였다.

• 한국통신학회논문지
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• 제19권6호
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• pp.1056-1063
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• 1994

본 논문에서는 연상 메모리 소자에 대한 데이터와의 병렬 처리 최적 정합 방식을 적용하여 계산 효율과 처리율을 높인 단일 PE 아키텍쳐를 이용하여 CAM을 설계하였다. 설계한 CAM은 크게 3개의 기능 블록(입력 MUX, 최적 정합 CAM, 제어부)으로 구성되어 있다. 데이터 처리는 병렬 입력 및 병렬 비교를 하여 고속으로 데이터를 처리하는 전.병렬 방식을 채택하였다. 이러한 특성을 갖는 CAM은 회로 및 논리 시뮬레이션을 통하여 ETRI 3 m-well 공정 설계 규칙을 사용하여 설계하였다. 본 논문에서 설계된 CAM의 최대 동작 주파수는 20MHz이다.