• Proceedings of the Korean System Dynamics Society
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• 2000.07a
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• pp.49-61
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• 2000

본 논문에서는 정책개입시기를 이해하고 논의하는데 있어서 시스템 다이내믹스 학자들의 연구가 어떠한 시사점을 줄 수 있는가에 관하여 논의한다. 정책 시스템을 피드백 루프를 중심으로 하여 양의 피드백 루프가 지배하는 시스템, 음의 피드백 루프가 지배하는 시스템, 음과 양의 피드백 루프가 지배하는 시스템을 구분한다. 그리고 각 시스템에 있어서 바람직한 정책 개입의 시기에 관하여 논의하고, 어떠한 인지적 편향과 제도적 장애가 있는지를 논의한다.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.655-664
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• 2014

Recently, many organizations are utilizing the team system. However, researches on a technique for efficient and effective feedback to improve a team performance is few. This study compared the relative effects of individual and group feedback on the quantity and quality of work performance. The task was to type English documents on a PC computer and both the number of words typed (quantity) and the percentage of correctly typed words (quality) were measured. Mixed design was adopted and 48 participants were randomly assigned to either individual or group feedback condition. Each group consisted of three participants and completed four sessions together. Under the individual feedback condition, each participant was provided with information on his/her own work performance, while under the group feedback condition, three participants were provided with information on their total work performance. Results showed that both feedback were effective to increase the quantity of performance. However, the effect size of treatment was more high under the group feedback than individual feedback. In addition, the accuracy of typed words was significantly improved only under the group feedback condition. Therefore, the group feedback was more effective and efficient than individual feedback to increase team performance. However, more studies are needed to generalize these results, especially, it is necessary to consider the cultural differences and type of task in the future studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.464-466
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• 2018

In this paper, a dense cellular network is considered in which each base station equipped with multiple antennas simultaneously communicates with multiple single-antenna users. Based on limited feedback, each user feeds back its quantized channel state information (CSI) to its associated transmitter, and the transmitter broadcasts multiple data streams prepared for the scheduled users using a space-division multiple access scheme. As the amount of CSI is limited at the transmitter, the downlink throughput increases with the number feedback bits. However, the increased number of feedback bits requires the correspondingly increased amount of uplink resources. Thus, an appropriate balance between the downlink throughput and the uplink resource usage should be considered in realistic systems. A net spectral efficiency defined in this context is used in this paper, and the optimal number of feedback bits that maximizes the net spectral efficiency is analyzed. This paper particularly focuses on the case when the received signal power is much smaller than the noise power.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3220-3229
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• 2015

This study analyzed the effect of team feedback environment on feedback-seeking behavior, and further explored how feedback-seeking behavior led to the feeling of thriving at work and team commitment. Also, we examined the moderating effect of self-efficacy on the relationship between team feedback environment and feedback-seeking behavior. Using survey data from 201 workers employed in various industries in Korea, we found that team feedback environment was positively related to feedback-seeking behavior, and that the relationship was moderated by self-efficacy. In addition, feedback-seeking behavior was positively associated with the feeling of thriving at work and team commitment. The result suggests the importance of feedback-seeking behavior in improving performance as well as work attitude and energy. The result also emphasizes the critical role that team feedback environment plays, and the need to find ways to nurture the environment that fosters feedback seeking and giving.

• The KIPS Transactions:PartB
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• v.16B no.3
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• pp.247-256
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• 2009

Typical pseudo-relevance feedback methods assume the top-retrieved documents are relevant and use these pseudo-relevant documents to expand terms. The initial retrieval set can, however, contain a great deal of noise. In this paper, we present a cluster-based resampling method to select better pseudo-relevant documents based on the relevance model. The main idea is to use document clusters to find dominant documents for the initial retrieval set, and to repeatedly feed the documents to emphasize the core topics of a query. Experimental results on large-scale web TREC collections show significant improvements over the relevance model. For justification of the resampling approach, we examine relevance density of feedback documents. The resampling approach shows higher relevance density than the baseline relevance model on all collections, resulting in better retrieval accuracy in pseudo-relevance feedback. This result indicates that the proposed method is effective for pseudo-relevance feedback.

• Journal of Korean Elementary Science Education
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• v.24 no.2
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• pp.111-122
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• 2005

The goal of this study was to investigate the differences in the effect of feedback from different providers on elementary school students' science achievement and to examine the responses of the students regarding the feedback. Three 6th grade classes were chosen to be assigned as experimental group 1, experimental group 2, and control group, respectively. In experimental group 1, the teacher provided feedback with students concerning the formative evaluations which were conducted periodically. Experimental group 2 was the one in which students were organized into small groups to compose and exchange feedback with one another. No feedback was of offered to students in the control group. The results of the science achievement test indicated ,that the provision of feedback by the teacher resulted in more gains in student academic achievement. The interviews with students revealed that the learners made positive responses to the feedback provided by the teacher while they showed negative attitudes toward the feedback exchange among students. There were also differences in student responses to feedback between high and low achievers in science. Implications for science lessons and science education research were presented and discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.628-636
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• 2015

In this paper, we propose a non-convex compressed sensing(NCCS)-based channel state information(CSI) feedback scheme for massive multiple-input multiple-output(MIMO) systems. Combining the random vector quantization(RVQ), the proposed scheme permits a transmitter to obtain CSI with acceptable accuracy under substantially reduced feedback load. Furthermore, it recovers CSI from fewer measurements than that of existing convex compressed sensing(CCS)-based schemes even if the measurements are inaccurate and incomplete. Simulation results show that the proposed scheme achieves higher throughput than both existing CCS-based feedback scheme and random vector quantization(RVQ) feedback scheme with the same feedback load.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.10-13
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• 2015

This paper proposed a novel user's information feedback algorithm for improving network energy harvesting rate. The proposed algorithm is focused on determining energy harvesting users comparing increasing ratio of the amount of harvesting energy versus emitted energy and network threshold ${\alpha}$, which is critical harvesting parameter. Using this method, we can increase the rate of network energy harvesting preventing emitted energy from wasting inefficiently. The result of experiment in this paper shows that user's information feedback algorithm makes network energy harvesting rate more efficiently when it uses threshold ${\alpha}=15%$ to determine energy harvesting users.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.339-341
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• 2000

문서요약이란 문서의 기본적인 내용을 유지하면서 문서의 복잡도를 줄이는 작업이다. 인터넷과 같은 정보기술의 발달로 정보의 양이 급증함에 따라, 정보 과적재(information over load) 문제의 해결을 위해 자동 문서요약시스템의 필요성이 대두되었다. 본 논문에서는 의사 적합성 피드백(pseudo relevance feedback)에 의한 질의확장(query expansion) 기법을 적용한 자동 문서요약 모델을 제안한다. 제안하는 모델의 특징은 질의를 분해함으로써, 적합성 피드백 과정에서 질의가 편향(bias)되어 요약이 잘못되는 문제를 방지할 수 있다는 것이다. 신문기사를 대상으로 평가한 결과 제안한 모델이 질의확장을 적용하지 않은 방법이나 하나의 질의만을 유지하는 일반적인 적합성 피드백 모델보다 더 좋은 성능을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.31-34
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• 2005

디지털 이미지의 양이 증가함에 따라 원하는 이미지를 정확하고 빠르게 찾을 수 있는 방법의 필요성이 증가하고 있다. 이미지 검색 방법으로는 이미지의 색상이나 명암과 같은 시각적 특성을 검색 조건으로 이용하는 내용 기반 검색과 이미지를 설명하는 키워드를 검색 조건으로 이용하는 키워드 기반 검색이 있다. 하지만 이러한 방법만으로는 사용자가 원하는 이미지를 정확하게 찾기 힘들다는 문제점이 제기되어 왔다. 따라서 최근에는 검색 도중 사용자의 응답을 받아 사용자의 요구를 파악함으로써 향상된 검색 결과를 제공하는 적합성 피드백에 대한 연구가 많이 진행되고 있다. 하지만 적합성 피드백을 이용하는 방법들도 원하는 결과를 얻기 위해서는 여러 번의 피드백을 필요로 하고 질의 수행이 완료된 후에는 얻어진 피드백 정보를 재사용하지 못한다는 단점이 있다. 따라서 본 논문에서는 이미지에 키워드를 연결한 후 사용자의 피드백 정보를 반영하여 키워드의 신뢰도를 조절함으로써 키워드 기반 이미지 검색의 정확도를 높일 수 있는 모델을 제안한다. 제안된 모델에서는 사용자로부터 피드백을 받은 이미지뿐만 아니라 긍정적 피드백을 받은 이미지들이 공통적으로 가지는 시각적 특성과 유사한 시각적 특성을 가지는 다른 이미지들까지도 키워드의 신뢰도를 조정함으로써 좀 더 빠른 시간 내에 검색 결과의 정확도를 높이도록 한다.