• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1136-1144
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• 2010

In this paper, the effects of HARQ feedback error are evaluated in IEEE 802.16m system when the HARQ and ARQ interactions that utilize the HARQ feedback information is used. Also, the HARQ and ARQ interaction scheme considering HARQ feedback errors are proposed. The HARQ and ARQ interaction scheme improve the system throughput by using the HARQ feedback information instead of the ARQ feedback message, which reduce retransmission time. However, errors in the HARQ feedback information generate severe performance degradation. Especially, the local NAK errors between HARQ feedback error critically degrade the performance, because the local NAK errors lead the loss of ARQ blocks. We propose a channel state-based schemes for HARQ and ARQ interactions to mitigate the throughput degradation due to HARQ feedback errors. Simulation results show that the proposed scheme improves the throughput and the delay performance.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.35-35
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• 2000

In this paper, we introduce a conservative control approach using a full feedback map and suggest a switching control between the conservative and default control. For the conservative control, we use the coordinator which performs the conjunction operation of the full feedback map information of local supervisors. Since the switching control with the coordinator extends the ability of local supervisors in the decentralized supervisory control, we can solve the problem in case the coobservability condition can not be satisfied.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.659-665
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• 2001

Relevance feedback is the most popular query reformulation strategy in a relevance feedback cycle, the user is presented with a list of the retrieved documents and, after examining them, marks those which are relevant. In practice, only the top 10(or 20) ranked documents need to be examined. The main idea consists of selecting important terms, or expressions, attached to the documents that have been identified as relevant by the user, and of enhancing the importance of these terms in a new query formulation. The expected effect is that the new query will be moved towards the relevant documents and away from the non-relevant ones. Local analysis techniques are interesting because they take advantage of the local context provided with the query. In this regard, they seem more appropriate than global analysis techniques. In a local strategy, the documents retrieved for a given query q are examined at query time to determine terms for query expansion. This is similar to a relevance feedback cycle but might be done without assistance from the user.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.1
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• pp.9-14
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• 2002

Boolean retrieval is simple and elegant. However, since there is no provision for term weighting, no ranking of the answer set is generated. As a result, the size of the output might be too large or too small. Relevance feedback is the most popular query reformulation strategy. in a relevance feedback cycle, the user is presented with a list of the retrieved documents and, after examining them, marks those which are relevant. In practice, only the top 10(or 20) ranked documents need to be examined. The main idea consists of selecting important terms, or expressions, attached to the documents that have been identified as relevant by the user, and of enhancing the importance of these terms in a new query formulation. The expected effect is that the new query will be moved towards the relevant documents and away from the non-relevant ones. Local analysis techniques are interesting because they take advantage of the local context provided with the query. In this regard, they seem more appropriate than global analysis techniques. In a local strategy, the documents retrieved for a given query q are examined at query time to determine terms for query expansion. This is similar to a relevance feedback cycle but might be done without assistance from the user.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.745-751
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• 2004

In conventional boolean retrieval systems, document ranking is not supported and similarity coefficients cannot be computed between queries and documents. The MMM(Max and Min Model), Paice and P-norm models have been proposed in the past to support the ranking facility for boolean retrieval systems. They have common properties of interpreting boolean operators softly In this paper we propose a new soft evaluation method for web Information retrieval using local context analysis feedback model. We also show through performance comparison that local contort analysis feedback is more efficient and effective than MMM, Paice and P-norm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1498-1506
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• 1989

A new stabilization scheme is proposed in which the local state feedback is utilized in each decentralized controller for large-scale interconnected systems. In the proposed scheme, the controller is designed in two steps. First, the feedback gain of each decentralized controller is temporarily chosen so that the eigenvalues of each isolated subsystem are placed at the desired locations in the complex plane. Secondly, the feedback gain of each controller is compensated so that the time derivative of the Lyapunov function candidate for the overall closed-loop system should be negative. A sufficient condition which assures the global system to stable is given.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.364-370
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• 2010

In this paper, we propose a cooperative channel sensing scheme in the presence of feedback errors. Accurate local sensing results may not directly be applied to cooperative sensing due to feedback errors. We consider the cooperative channel sensing that utilizes local sensing results in good feedback channel condition. Finally, simulation results show that the proposed scheme can maximize the detection probability while guaranteeing desired false alarm probability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.464-473
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• 2006

This paper summarises theoretical and experimental work on the feedback control of sound radiation from honeycomb panels using piezoceramic actuators. It is motivated by the problem of sound transmission in aircraft, specifically the active control of trim panels. Trim panels are generally honeycomb structures designed to meet the design requirement of low weight and high stiffness. They are resiliently-mounted to the fuselage for the passive reduction of noise transmission. Local coupling of the closely-spaced sensor and actuator was observed experimentally and modelled using a single degree of freedom system. The effect of the local coupling was to roll-off the response between the actuator and sensor at high frequencies, so that a feedback control system can have high gain margins. Unfortunately, only relatively poor global performance is then achieved because of localisation of reduction around the actuator. This localisation prompts the investigation of a multichannel active control system. Globalised reduction was predicted using a model of 12 channel direct velocity feedback control. The multichannel system, however, does not appear to yield a significant improvement in the performance because of decreased gain margin.

• English Language & Literature Teaching
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• v.16 no.1
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• pp.19-40
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• 2009

Teacher written feedback on student compositions has received tremendous attention in second language (L2) writing research. Notwithstanding the importance of understanding both teachers' and students' perspectives on the feedback process, much of the feedback research has only looked into one-side of the story - adopting either the teacher's or the student's perspective. The current study is an attempt to look into both sides of the story by examining the types of written feedback that students prefer, the extent to which students' preferences and teachers' actual feedback practice overlap, and the extent to which student perceptions of teacher feedback coordinate teacher self-reflections on their feedback practice. Three English composition classes (3 teachers and 46 students) at a university participated in this study. It analyzed student and teacher data from questionnaires and teacher written feedback on student compositions. The results showed that students' preference for feedback on global and local issues varied across the three composition classes. This is partly a consequence of how students perceived the type of feedback that their teachers practiced. Teacher self-reflection on and student perception of teacher written-feedback generally coordinated. These findings are discussed in light of how contextual factors affect learner perception of teacher written feedback and underscore the need for examining students' reactions to feedback and teacher self-reflection.

• Journal of Korean society of Dental Hygiene
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• v.21 no.4
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• pp.481-489
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• 2021

Objectives: This study was conducted to understand the effect of learners' self-determination on class participation, focusing on the feedback type of educators. Methods: A survey was conducted from May 1 to May 31 2021 on dental hygiene students, and a total of 151 valid responses were analyzed. The questionnaire consisted of general characteristics, self-determination, class participation, and educator's feedback type. The analysis method used correlation analysis and hierarchical regression analysis. Results: In relation to self-determination, class participation, and feedback type of educators, self-determination was positive feedback (r=0.338, p<0.01), class participation was corrective feedback (r=0.418, p<0.01), and positive feedback was correction (r=0.742, p<0.01). As a result of the mediating effect of the educator's feedback type in the relationship between self-determination and class participation, it was found to be significant by partially mediating positive and corrective feedback. Conclusions: It was found that the right to self-determination influences class participation based on positive feedback and corrective feedback of educators. It relates to efforts to strengthen learners' self-determination and provide appropriate types of feedback from educators.