• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5C
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• pp.302-308
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• 2011

In this paper we propose a coordinated beamforming(CBF) scheme considering the effects of feedback quantization and delay in time-varying multiple-input multiple-output(MIMO) broadcast channels. By equal power allocation per data stream, the proposed CBF scheme transmits multiple data streams per user terminals without additional feedback overhead when quantized feedback information is used. The proposed CBF scheme also applies a linear channel predictor to each user terminals to prevent errors due to feedback delays that are not evitable in practical wireless systems. Each user terminal utilizes Wiener filter to predict future channel responses and generates feedback information based on the predicted channels. Consequently the proposed CBF scheme adapting Wiener filter improves system performances compared with the conventional scheme using delayed feedback.

• Communications of Mathematical Education
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• v.25 no.2
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• pp.431-450
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• 2011

Formative assessment is considered one of the effective strategies for teaching and learning mathematics. But it seems that there are few systematic researches which cover the process of practicing formative assessment in a class and providing feedback to the students. This study adopts CRESST Formative Assessment Program as a prototype. After some modifications of it to suit our educational system, this study analyzes the effectiveness of applying that program to the 7th grade level-differentiated math classes. Afterwards, this study tries to draw some significant educational discussions and implications for improving teaching and learning mathematics.

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.165-174
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• 1997

고강도 및 보통강도 콘크리트의 압축파괴 거동에 영향을 미치는 요소들 (재료의 강도, 시편의 세장비, 전단구속, 실험장치의 강성, 피드백 신호)에 관한 연구가 수행되었다. 피드백 신호로 자동 조절되는 유압 실험기계항에서 원주변형 피드백 신호를 사용하여 연화곡선을 구했다. 재하장치로부터의 단부 전단 구속을 줄이면 제한된 영역 안에서 재하방향 균형이 형성되고, 또한 연화곡선의 경사가 급해지고 파괴에너지도 작아진다. 이때 길이가 큰 시편에서 파괴에너지가 커지는 것은 안장과는 달리 단순균열이 형성되는 것이 아니고 , 파괴가 용적을 가진다는 것을 의미한다. 압축응력하의 국부 파괴는 재료특성이 아니므로, 단부 전단구속이 없더라도 재료적 특성으로서의 응력-변형도 곡선은 정하기 어렵다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.704-711
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• 2013

Applying channel state information feedback scheme based on codebook for FDD downlink MIMO system to massive MIMO system directly causes following two problems. First, codebook generation becomes hard because resources needed for codebook generation increases exponentially in the number of antennas. In addition, long time is needed for channel state information feedback because users's codebook search time increases linearly in the number of antennas. This paper proposes a codebook generation scheme and a codebook search scheme which can reduce resource for codebook generation and codebook search time drastically though they have similar performance as conventional approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1410-1413
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• 2016

Array beamforming for anti-jamming means that jamming signals are superposed destructively, while superposing information signals constructively at a receiver. However, according to channel state variation, the anti-jamming performance of the beamforming can be degraded because of large beamwidth of the sidelobe and lower selectivity of the mainlobe. To mitigate this problem, we introduce a beamformed decoy signal which uses frequency band distinguished from the information signal to make the jammer concentrate its jamming power to a wrong target under limited feedback. In this paper, we show that the performance of the proposed scheme can approach that of optimal one with perfect feedback.

• Journal of The Korean Association For Science Education
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• v.20 no.3
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• pp.479-490
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• 2000

The purpose of this study was to examine the effects of formative assessment with detailed feedback on students' science achievement, attitude, and interactions between the teacher and the students. For the study, 133 seventh graders were selected from a girl's middle school in Seoul, and assigned to the experimental and the control groups. The duration of the treatment was over a period of nine weeks. In the experimental group, detailed feedbacks on the solution, teacher's comments on the results, and relevant references were provided after each formative assessment. However, only the answers were presented in the control group. Prior to instructions, a achievement and a attitude tests were administered. After the instructions, follow-up tests which were similar to the pretests were also administered. The results showed significant difference between the two groups in science achievement. It was found that the usage of formative assessments with detailed and supportive feedbacks was more effective in stimulating students' interest, raising their confidence in the subject, increasing their participation, as well as reducing their anxiety. The results also strongly indicated that detailed feedbacks were more effective in improving the interactions of the teacher and the students. The results strongly suggest that formative assessment utilizing detailed and supportive feedback is a necessary component of effective science teaching and learning.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.75-88
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• 2021

Along with the advent of the Fourth Industrial Revolution, fostering young talents with convergent mind is getting important. Moreover pre-service teachers' ability to design proper convergent classes can be a meaningful issue for high quality future education. This study proposes the role of professors' exquisite feedback is so significant for developing their competence in STEAM education, It analyzed how various theories regarding feedback support them to enhance convergent knowledge with e-learning. They participated in the 5 step group and individual activities for creating STEAM lesson plan and received suitable feedback. Lastly a survey was performed. The researchers did modeling how integrative feedback was applied to the procedure step by step according to the 'Ladder of Inference' theory. This strategic model contributed to elevating the participants' convergent knowledge, competence, achievement and satisfaction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.822-824
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• 2012

21세기는 유전자, 질병검사를 통해 질병 예방, 예후 관리, 재택 및 원격 진료 시스템을 구축하여 초고감도, 실시간으로 환자의 건강 상태를 모니터링 하고, 진단, 처방할 수 있는 IT/BT/NT를 결합한 유비쿼터스 의료 시스템이 대두할 것으로 기대되고 있다. 유비쿼터스 의료 시스템의 핵심적인 역할을 할 것으로 기대되는 바이오센서는 측정 기술로서 획기적인 발전을 거듭하고 있으며 생물학, 화학, 의학, 전자, 물리, 컴퓨터, 기계 공학 등 최첨단 학문의 관련 기술이 복합적으로 융합되면서 실용화에 필요한 요소 기술들이 접목되고 점점 소형화, 시스템화 되어 가고 있는 추세이다. 특히 SiNW(silicon nanowire) 바이오센서 같은 경우 양쪽의 전극이 소스와 드레인 역할을 하고 SiNW receptor가 검출대상과 결합하면 게이트 역할을 하게 된다. 불순물의 농도에 따라 전기적 특성이 결정되는데 검출하고자하는 대상이 receptor와 결합하게 되면 마치 MOS에서 게이트에 전압을 인가한 동작과 같은 역할을 하게 되어 소소와 드레인 사이에 채널이 형성되고 하나의 저항처럼 동작하게 된다. 본 논문에서는 기존의 MOS를 이용하여 현재 전자소자나 바이오센서 등 많은 분야에서 응용되고 있는 SiNW 바이오센서의 기능과 유사하게 피드백 회로를 통해 구현하였다. 피드백 회로의 정상 작동 확인과 SiNW 바이오센서의 역할을 대체한 MOS 소자의 정상 작동을 확인을 위해 블루투스 통신을 이용하여 모니터에 전압 값을 표시한다.

• Journal of Engineering Education Research
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• v.13 no.1
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• pp.62-69
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• 2010

Program learning outcome is widely used for assessing and improving program quality. There are various methodologies that can measure program quality and improve program learning outcomes. In this paper, we used formative approach in Capstone design course, since it is the most effective in terms of improving program learning outcomes due to the course's intrinsic nature. To integrate a formative approach into Capstone design course, we develop a feedback structure which is a key element in formative approach and define several sub phases that manage feedback structures and their own evaluation criteria. As a result, we observed a noticeable improvement for students performance in capstone design course.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.202-205
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• 2005

대부분의 실험상황과 달리 실제 상황에서 사람들은 의사결정에 필요한 정보를 직접 획득해야 한다. 기존의 연구는 정보 획득 방략이 고정된 것으로 간주하였다. 그러나 반복적인 의사결정은 환경에 대한 피드백 학습을 가능케 하여 심적 모형 형성에 영향을 미치며, 심적 모형의 변화는 정보 획득 방략의 변화를 초래한다. 이 연구에서는 심적 모형 형성과 정보 획득 방략의 변화에 대해 고찰하였다.