• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.286-290
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• 2001

This paper presents a full-digital low-level controller for a robotic material transfer system which has been developed for a computer-integrated manufacturing model plant. Compared to conventional analog or hybrid type controllers in current industrial environments, this controller system has some advantages such as strong noise-immunity, easy control algorithm implementation, etc The servo-controller consists of two modules, a position controller and a DC servo motor driver. The position controller operates position feedback routines by receiving position encoder data and sending control outputs to the driver. The position controller is implemented in a full-digital way using a recently introduced microcontroller. The DC servomotor driver controls speeds and torques. The driver consists of a micro-controller and insulated-gate-bipolar-transistors (IGBT). The micro-controller provides control signals, and the IGBT's amplifies the control signals and sends them to the motor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.110-110
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• 2001

By the state transformation including independent outputs functions, a nonlinear process model can be decomposed into two subsystems; the one(design model) is described in output variables as new states and used for control system synthesis and the other(disturbance model) is described in the original unavailable states and its couplings with the design model are treated as uncertain time-varying parameters in the design model. Its existence with respect to the design model is ignored. So, the design model is and uncertain time-variant system. Control synthesis based on a reduced design model is a combined form of a time-variant input-output linearization with parameter estimation. The parameter estimation is also based on the design model and it gives the parameter estimates such that the estimated outputs follow the actual outputs in a specified way. The disturbances form disturbance model and as well all the other uncertainties affecting the outputs will be reflected into the estimated parameters used in the linearizing control law.

• 제어로봇시스템학회논문지
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• 제9권3호
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• pp.186-195
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• 2003

This paper deals with eigenvalue assignment techniques for linear time-varying systems as a way of achieving feedback stabilization. For this, the novel eigenvalue concepts, which are the time-varying counterparts of the conventional (time-invariant) eigenvalue notions, are introduced. Then, the Ackermann-like formulae for SISO/MIMO linear time-varying systems are proposed. It is believed that these techniques are the generalized versions of the Ackermann formulae for linear time-invariant systems. The advantages of the proposed Ackermann-like formulae are that they neither require the transformation of the original system into the phase-variable form nor compute the eigenvalues of the original system. Two examples are given to demonstrate the capabilities of the proposed techniques.

• 정보통신설비학회논문지
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• 제9권3호
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• pp.119-123
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• 2010

Since the two-way interactive broadcasting service began, remote controllers have been fitted with 4 color buttons, which enable interaction and convenience to grow between users and content. With Currently, diverse studies on IPTV are in progress. Particularly, as the mobile market rapidly grows, studies on mobile IPTV and on linkage with other media are constantly increasing. Yet, mobile IPTV has never been studied as of now. In that sense, the present study attempted to design a mobile-based IPTV UI that is fitted with more usability and functionality of 4 color buttons and multi-dimensional search based on consistent criteria for content search. The UI designed in this study was estimated using user interface design guideline. The guideline is comprised of consistency, user centered, ease of use, forgiveness, feedback, functionality, aesthetic integrity.

• 충청수학회지
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• 제21권2호
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• pp.259-268
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• 2008

To the design of secret key, there are two types of basic approaches called the tame approach and the wild approach. In the tame approach we try to use only simple primitives such as linear feedback shift registers and to prove mathematical theorems about their cryptographic properties. In the wild approach we try to use crazy compositions of operations which mix a variety of domains in a nonlinear and nonalgebraic way. There are several papers which try to bridge this gap by considering semi-wild constructions. A T-function on n-bit words plays an important role in semi-wild constructions. In this paper we study the invertibility and the period of some T-functions. Especially we characterize some polynomials which has a single cycle property.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2005년도 추계 학술대회 발표논문집
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• pp.17-20
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• 2005

The purpose of this project is to develop a device that can automatically measure pronunciation of English speech produced by Korean learners of English. Pronunciation proficiency will be measured largely in two areas; suprasegmental and segmental areas. In suprasegmental area, intonation and word stress will be traced and compared with those of native speakers by way of statistical methods using tilt parameters. Durations of phones are also examined to measure speakers' naturalness of their pronunciations. In doing so, statistical duration modelling from a large speech database using CART will be considered. For segmental measurement of pronunciation, acoustic probability of a phone, which is a byproduct when doing the forced alignment, will be a basis of scoring pronunciation accuracy of a phone. The final score will be a feedback to the learners to improve their pronunciation.

• 한국통신학회논문지
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• 제24권12A호
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• pp.2015-2024
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• 1999

디지털 통신 시스템의 기저대역 신호처리를 효율적으로 구현하기 위한 새로운 복소수 필터구조를 제안하고, 이를 적용하여 채널등화용 적응 결정귀환 등화기 (Adaptive Decision-Feedback Equalizer; ADFE) 칩셋을 설계하였다. 새로운 복소수 필터구조는 기존의 2의 보수 대신에 redundant binary (RB) 수치계를 적용한 효율적인 복소수 승산 및 누적연산을 바탕으로 한다. 제안된 방법을 적용하면, N-탭 복소수 필터는 2N개의 RB 승산기와 2N-2개의 RB 가산기로 구현되며, 필터 탭 당 Tm,RB＋Ta,RB (단, Tm,RB, Ta,RB는 각각 RB 승산기 및 가산기의 지해 고속동작이 가능하다. 제안된 방법을 적용하여 설계된 ADFE는 FFEM (Feed-Foreward Equalizer Module)과 DFEM (Decision-Feedback Equalizer Module)로 구성되며, 필요에 따라 필터 탭을 확장할 수 있도록 설계되었다. 2-탭 복소수 필터, LMS 계수갱신 회로 및 부가회로 등으로 구성되는 각 모듈은 COSSAP과 VHDL을 이용한 모델링 및 검증과정을 거쳐 0.8-㎛ SOG (Sea-Of-Gate) 셀 라이브러리를 사용하여 논리합성 되었으며, 26,000여개의 게이트로 구성된다.

• 한국과학교육학회지
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• 제40권5호
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• pp.543-563
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• 2020

본 연구는 초등학교에서 과학적 모델 구성 수업을 적용하는 동안, 두 교사의 수업 실행이 어떻게 변화하였는지 탐색하고, 이러한 변화를 교사의 모델링 PCK 발달 측면에서 이해하고자 하였다. 연구 참여자는 초등학교 5학년 2개 반 학생들과 이들을 가르치는 교사 2명이었고, 과학의 '우리 몸의 구조와 기능' 단원에서 4가지 주제로 총 8차시 동안 모델링 수업을 도입하였다. 자료 분석은 전체 수업 중 교사의 변화를 가장 잘 보여주는 수업 초반(1-2차시)과 수업 후반(7-8차시)을 대상으로 이루어졌으며, 두 교사의 수업 실행 변화 및 이와 연관된 모델링 PCK를 분석하였다. 수업 실행 변화는 GEM cycle의 모델 생성, 평가, 수정 단계에서 각 단계에 할애한 시간과, 피드백의 양 및 피드백의 내용 측면에서 분석되었다. 연구 결과, A교사는 수업 전반에 걸쳐 교사 주도적으로 평가와 수정 단계를 이끌었으며, 수업 초반에 비해 후반에 모델 평가 및 수정 단계에 사용한 시간이 증가하였다. 또한 피드백 측면에서 수업 초반에는 정답 평가 피드백을 사용하였으나, 수업 후반에는 사고 유도 피드백을 사용하는 것으로 피드백의 내용이 변화하였다. 한편, B교사는 수업 초반에는 거의 교사 주도적으로 모델을 평가하고 수정하였으나, 수업 후반에는 메타 인지적 피드백 등 다양한 종류의 피드백을 통해 학생 주도적으로 모델을 평가하고 수정하게 함으로써, 그들이 스스로 지식을 구성하고 모델을 발달시킬 수 있도록 도왔다. 인터뷰 결과, 두 교사의 수업 실행 변화는 여러 가지 모델링 PCK 구성요소의 발달이 바탕이 된 것으로 분석되었다. 또한, 두 교사의 수업 실행 변화 정도가 다르게 나타난 원인을 모델링 PCK에서 탐색한 결과, 두 교사는 모델링 PCK 중에서 교수 지향, 모델링 단계에 대한 이해, 모델링의 가치 인식 정도에서 차이를 보여, 모델링 수업 실행에서 이것의 중요성을 암시한다. 본 연구는 교사의 모델링 수업 실행 변화의 사례를 제공하고, 이와 관련된 모델링 PCK를 밝힘으로써 모델링 수업 개선 방법에 대한 이해 증진에 도움을 줄 수 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1406-1424
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• 2017

Recent advancements in network infrastructures provide increased opportunities to support data delivery over multiple paths. Compared with multi-homing scenario, overlay network is regarded as an effective way to construct multiple paths between end devices without any change on the underlying network. Exploiting multipath characteristics has been explored for TCP with multi-homing device, but the corresponding exploration with overlay network has not been studied in detail yet. Motivated by improving quality of experience (QoE) for reliable data delivery, we propose a multipath message transport protocol based on application level relay (MPMTP-AR). MPMTP-AR proposes mechanisms and algorithms to support basic operations of multipath transmission. Dynamic feedback provides a foundation to distribute reasonable load to each path. Common source decrease (CSD) takes the load weight of the path with congestion into consideration to adjust congestion window. MPMTP-AR uses two-level sending buffer to ensure independence between paths and utilizes two-level receiving buffer to improve queuing performance. Finally, the MPMTP-AR is implemented on the Linux platform and evaluated by comprehensive experiments.

• 음성과학
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• 제11권2호
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• pp.27-38
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• 2004

This study attempted to determine the effects of a cooperative and cognitive group therapy compared to individual therapy in 24 aphasic subjects. Two dependent variables were measured overall language performance, functional communication skills. 18 subjects with different types and severity of aphasia participated in the group therapy. 6 aphasic subjects participated in the individual therapy and they functioned as a control group. The subjects were ranged from 27 to 59 years in age. The group therapy using the cooperative learning utilized the following procedures. First, 6 aphasics constituted 1 group where each subject peformed a task and they monitored one another. Second, 2 aphasics consisted 1 group and they cooperated to perform a task. Third, 3 groups with 2 aphasics in a group competed one another in a task where the 2 aphasics had to cooperated. Finally, the investigator gave the feedback to the group and she and the subjects discussed the overall procedures of the therapy. The above mentioned 2 tests were administered pre- and post-treatment. A repeated two-way ANOVA was performed for analysis. The results showed that the group therapy was more effective in improving overall language performance as compared to the individual therapy. And, the group therapy was more effective in increasing functional communication skills as compared to the individual therapy.