• 한국멀티미디어학회논문지
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• 제21권11호
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• pp.1353-1361
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• 2018

With the availability of real-time educational data collection and analysis techniques, the education paradigm is shifting from educator-centric to data-driven lectures. However, most offline and online education frameworks collect students' feedback from question-answering data that can summarize their understanding but requires instructor's attention when students need additional help during lectures. This paper proposes a content restructure recommendation framework based on collected student feedback. We list the types of student feedback and implement a web-based framework that collects both implicit and explicit feedback for content restructuring. With a case study of four-week lectures with 50 students, we analyze the pattern of student feedback and quantitatively validate the effect of the proposed content restructuring measured by the level of student engagement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.172-178
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• 1993

This paper deals with the modeling and experiment of a robot system for force/impact control performance. The basic model is composed of a direct drive motor, servo amplifier, link, force sensor and environments. Based on the developed model, the stability of the whole system was analyzed via root locus method. For the force control, integral force compensation with velocity feedback method shows the best performance of all the explicit force control strategies. In dealing with impact, PID position control and the explicit force control method were implemented. Instead of add more damping to the robot system by velocity feedback, we developed a new passive damping method and it was also applied to enhance the damping characteristic of the system.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.53-62
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• 2006

In this paper, ATM network congestion control with explicit rate feedback is considered. In ATM networks, delays commonly appear in data transmission and have to be considered in congestion control design. In this paper, a bounded single round delay on the return path is considered. Our objective is to design an explicit rate feedback control that achieves a robust optimal $H_2$ performance regardless of the bounded time-varying delays. An optimization approach in terms of linear matrix inequalities (LMIs) is given. Saturation in source rate and queue buffer is also taken into consideration in the proposed design. Simulations for the cases of single source and multiple sources are presented to demonstrate the effectiveness of the design.

• Journal of Information Technology Applications and Management
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• 제21권3호
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• pp.19-33
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• 2014

Crowdsourcing is a popular tool for firms to harness external knowledge and resources. One variation of crowdsourcing entails the use of corporate channels in social network services (SNS) such as Twitter to hold public idea competitions. This study examined the role of feedback interaction between participants of idea competitions. More specifically, the study examined the impact of incentives to provide feedback on other participants' ideas. We found that idea competitions where explicit incentives were introduced to elicit crowdsourced feedback in the form of qualitative comments resulted in improved idea generation performance-with more ideas generated overall, and more ideas generated through participant collaborations, through increased comment-posting activities. Based on the findings, implications for theory and practice are discussed.

• 전기전자학회논문지
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• 제23권4호
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• pp.1265-1272
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• 2019

본 논문에서는 상수 입력지연을 갖는 이산시간 선형시스템을 위한 기존의 예측기 피드백 제어기의 구조적 모델 불확실성에 대한 강인성을 해석한다. 상수 입력지연을 1차 PdE (Partial difference Equation)로 모델링하여 입력지연을 PdE 상태변수로 대체하고 백스테핑 변환을 적용하여 목표 시스템을 구축한다. 목표 시스템을 기반으로 전체 상태변수를 포함하는 명시적 리아푸노프 함수를 구성하여 안정성이 유지되는 구조적 모델 불확실성의 최대 크기의 존재를 증명하고 예측기 피드백 제어기의 강인성을 확립한다. 모의실험을 통하여 모델 불확실성이 존재하는 경우에도 닫힌 루프 시스템의 안정성이 유지되는 것을 예증하고 예측기 피드백 제어기의 강인성을 검증한다.

• 디지털콘텐츠학회 논문지
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• 제18권8호
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• pp.1561-1566
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• 2017

기계 학습과 인공 지능 기술의 발전으로 다양한 응용분야들이 가능해지고 있고, 이중에 추천 시스템은 이미 여러 업체들에서 영화 추천이나 상품 추천 등의 서비스에 적용하여 효과를 보고 있다. 이러한 서비스 중인 추천 시스템들의 대부분은 아이템의 내용을 분석하여 추천하거나 아니면 평점과 같은 직접적인 피드백에 기반하여 시스템을 학습하고 추천하고 있다. 하지만 많은 온라인 쇼핑몰 중에는 아이템의 내용을 분석하는 것이 어렵고, 직접적인 피드백 정보가 없거나 혹은 거의 없어 추천 시스템 구축이 어려운 경우가 많다. 이러한 경우에도 사용자의 상품 조회에 관한 로그 기록들은 어렵지 않게 확보할 수 있고, 로그 기록들만 가지고도 추천 서비스를 제공할 수 있다면 서비스의 질을 향상할 수 있을 것으로 기대된다. 본 논문에서는 사용자의 로그 기록으로부터 암묵적인 피드백인 상품 조회 정보를 추출하고, 암묵적인 피드백에 기반한 추천 시스템을 구현하고, 제안된 시스템은 온라인 반려동물 용품점에 적용하여 확인한다. 즉, 사용자들의 상품조회를 위한 클릭정보만을 활용하여 반려동물 용품 추천 시스템을 구축하여 서비스로 확인한다.

• 영어어문교육
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• 제13권1호
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• pp.111-131
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• 2007

This study explores teacher's corrective feedback types in an error treatment sequence in Korean EFL classroom setting. Corrective feedback moves are coded as explicit correction, recast, or initiations to self-repair. The frequency and distribution of each corrective feedback type are examined. But the special focus was given on feedback types eliciting learner's self-repair (clarification request, metalinguistic feedback, elicitation, and repetition of error) because initiations to self-repair are believed to facilitate language learning more than other strategies. The results of the study are as follows. First, there was an overwhelming tendency for teacher to use recasts whereas initiations to self-repair were not used as much as recast (52.4% vs. 29.5%). Second, the teacher tended to select feedback types in accordance with error types: namely, recasts after phonological, lexical, and translation errors and initiations to self-repair after grammatical errors though the differences were not significant. Finally, teacher's belief and students' expectation on corrective feedback were compared with actual corrective feedback representations respectively and some mismatches were found. Though both teacher and the students acknowledged the importance and necessity of self-repair, self-repair were not put into practice as such. Therefore, this study suggests more initiations to self-repair be used for effective language learning.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1435-1437
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• 2003

In this paper, we proposed static output feedback model predictive control for Wiener models. We adopted polytopic uncertainty description of Wiener Model Predictive Control (WMPC) algorithms for considering output nonlinearities. Robust stability conditions have been presented under which the closed loop stability of static output feedback MPC is guaranteed. The proposed control law is determined from the static output feedback WMPC based on the current estimated state with explicit satisfaction of input constraints.

• 전기학회논문지
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• 제58권8호
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• pp.1592-1594
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• 2009

This paper presents an LMI-based method to design a reduced order output feedback sliding mode controller for a class of uncertain systems. Using LMIs we derive an existence condition of a reduced order sliding mode control law. And we give explicit formulas of the gain matrices. Finally, we give a numerical design example, together with a design algorithm.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.382-384
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• 1988

The explicit form of time correlation function between fluctuating concentrations is obtained for the model of metabolic system with negative feedback near a stable(or marginally stable) steady state.