• 한국융합학회논문지
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• 제11권3호
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• pp.67-75
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• 2020

난이도는 학습자가 컨텐츠를 선택하는 중요한 기준 중 하나이다. 하지만, 대부분의 난이도 기준은 컨텐츠 제공자가 획일적으로 결정한다. 이러한 방식으로는 학습자의 다양한 수준과 환경을 고려한 맞춤형 교육을 지원할 수 없다. 본 연구는 이 문제를 해결하기 위하여 학습자와 컨텐츠의 지식을 정형화하고 일반화한 후, 이를 실험하기 위한 객체 모델과 맞춤형 난이도 척도를 설계하였다. 또한, 이를 검증하기 위한 목적으로 구현한 도구를 이용하여 100개의 음악 교육 컨텐츠와 20명의 학습자를 기반으로 시뮬레이션을 진행했다. 실험 결과는 제안한 방법이 학습 상태와 컨텐츠에서 정의한 지식의 유사도를 이용하여 맞춤형 난이도를 계산할 수 있음을 보여 주었다. 제안한 접근법은 학습 상태와 컨텐츠에 쉽게 접근할 수 있는 온라인 학습 시스템에 효과적으로 적용할 수 있다.

• 한국간호교육학회지
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• 제14권1호
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• pp.63-72
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• 2008

Purpose: This study focused on two aspects: 1) how to design and implement a mobile learning course which is facilitated by a PDA with a web-based class homepage as a tool for mobile learning; 2) how to increase and enhance interactive activities among and between the students and the faculty members by utilizing a PDA as a tool for communication as well as collaboration. Method: To analyze the results of the m-Learning course, data was collected from interviews with the involved two faculty members and a survey from 27 students. Result: The results showed a positive outcome of the m-Learning approach in terms of a more collaborative learning environment in a clinical course where the students practice their clinical activities out of the classroom, far from their faculty members. On the other hand, the problems of the m-Learning approach were that more thorough preparation was needed for the new tools from both the students and the faculty members in preparation in social, cultural, and mental aspects, not withstanding the assumed technical limits of a PDA. Conclusion: m-Learning must be more actively implemented in classes, even though several problems were noticed in terms of both technical aspects of the tools, and social and cultural aspects from the users.

• 과학교육연구지
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• 제46권3호
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• pp.278-292
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• 2022

서비스 러닝(service learning)은 최근 환경문제를 동반한 기후변화에 대처하기 위한 새로운 교육적 접근으로 새롭게 주목받고 있다. 그러나 국내 과학교육에서는 서비스 러닝에 대한 연구들이 부족하다. 이 연구에서는 기존의 관련 문헌들을 바탕으로 서비스 러닝에 대한 이론적 배경을 소개하고, 환경문제에 대한 과학교육의 새로운 접근 방법으로서 국내 과학교육 환경에서도 적용될 수 있는 개념적 틀을 제시하고자 하였다. 이를 위해 서비스 러닝과 관련하여 국내외 데이터베이스 검색을 통해 수집된 112편의 문헌들을 연구 대상으로 하여 분석하였다. 그 결과, Dewey의 경험학습에 뿌리를 둔 서비스 러닝의 이론적 배경을 소개하였고, 서비스 러닝을 학생들이 학습 내용과 관련된 구조화된 서비스 활동을 통해 지역사회가 필요로 하는 도움을 제공하고, 그와 동시에 학문적 이해의 깊이를 더하며, 나아가 사회 구성원으로서 공동체 의식과 책임감을 함양하는 형태의 경험학습으로 정의하였다. 또한 환경문제에 대응하기 위해 국내 과학교육 환경에 적용하기 위한 서비스 러닝의 개념적 틀을 제안하였다. 제안된 틀은 서비스 러닝의 구성원을 학교, 학생, 지역사회로 구분하고, 지식, 경험, 그리고 비판적 성찰(critical reflection)을 통한 학습을 그 핵심요소로 제시하고 있다. 기후변화, 생물 다양성, 대기오염, 산림황폐화 등을 포함한 다양한 환경문제를 다루기 위한 방안으로 우리나라 과학교육에서도 서비스 러닝을 적극적으로 활용할 필요가 있다. 따라서 제안된 서비스 러닝의 개념적 틀을 바탕으로 학교현장에서 지역사회 환경문제를 다루기 위해 다양한 형태로 적용하고 검증하는 연구들이 추가적으로 수행되어야 할 것이다.

• 한국음향학회지
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• 제43권2호
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• pp.178-183
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• 2024

본 연구는 데이터 기반의 딥러닝 접근 방식을 통해 도달 방향 추정의 정확성과 정밀성의 개선을 통해 보다 강건하고 정확한 음원 위치 추적 기술을 제안한다. 본 연구에서는 도달시간 차 기반의 음원 위치 추적법을 개선함을 목적으로 하며, 이를 위해 상호상관함수로부터 정확하고 정밀한 시간 지연을 추정한다. 실제 마이크로폰으로부터 계측된 값은 많은 잡음이 혼입된 형태이므로, 따라서 실제 도달시간 차이를 정확히 추정하는 것이 여전히 이 분야의 한계로 남아있다. 또한, 마이크로폰으로 부터 실제 신호를 계측하는 과정에서 신호는 디지털화가 되며, 계측 시스템의 샘플링 주파수에 의해 측정 정밀도가 한정되는 양자화 오류를 수반한다. 본 연구에서는 딥러닝 기반 접근법을 통해, 기존의 방법이 가지는 한계를 극복한다. 또한 본 연구에서는 획득된 상호상관함수로부터 시간 지연을 추정하는 원리를 분석하기 위해, 두 개 및 세 개의 마이크로폰으로 구성된 배열에 대한 검증을 수행한다. 마지막으로, 실험을 통해 본 방법의 실제 활용성을 검증한다.

• International Journal of Contents
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• 제12권4호
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• pp.31-44
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• 2016

Knowledge creation and management are regarded as critical success factors for an organization's survival in the knowledge era. As a process of knowledge acquisition and sharing, organizational learning mechanisms (OLMs) guide the learning function of organizations represented by its different learning activities. We examined a variety of learning processes that constitute OLMs. In this study, we aimed to capture the process and framework of OLMs and knowledge sharing and acquisition. Factors facilitating OLMs were investigated at three levels: individual, group, and organizational. The concept of an OLM has received some attention in the field of organizational learning, however, the relationship among the factors generating OLMs has not been empirically tested. As part of the ongoing discussion, we attempted a systemic approach for OLMs. OLMs can be represented by factors that are inherent to the organization's system; therefore, prior to empirically testing the OLM generating factor(s), evaluation of its organizational integration is required to determine effective treatment of each factor. Thus, we developed a framework to manage knowledge and proposed a method to numerically evaluate factors influencing the OLMs. Specifically, composite importance (CI) of the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method was applied to explore the interaction effect of these factors based on systemic approach. The augmented matrix thus generated is expected to serve as a stochastic matrix of an absorbing Markov chain.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2650-2662
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• 2012

Due to the semantic gap issue, the performance of automatic image annotation is still far from satisfactory. Active learning approaches provide a possible solution to cope with this problem by selecting most effective samples to ask users to label for training. One of the key research points in active learning is how to select the most effective samples. In this paper, we propose a novel active learning approach based on sparse graph. Comparing with the existing active learning approaches, the proposed method selects the samples based on two criteria: uncertainty and representativeness. The representativeness indicates the contribution of a sample's label propagating to the other samples, while the existing approaches did not take the representativeness into consideration. Extensive experiments show that bringing the representativeness criterion into the sample selection process can significantly improve the active learning effectiveness.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3283-3292
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• 2022

Based on the Deep Q-Network(DQN) algorithm of reinforcement learning, an active fault-tolerance method with incremental action is proposed for the control system with sensor faults of the once-through steam generator(OTSG). In this paper, we first establish the OTSG model as the interaction environment for the agent of reinforcement learning. The reinforcement learning agent chooses an action according to the system state obtained by the pressure sensor, the incremental action can gradually approach the optimal strategy for the current fault, and then the agent updates the network by different rewards obtained in the interaction process. In this way, we can transform the active fault tolerant control process of the OTSG to the reinforcement learning agent's decision-making process. The comparison experiments compared with the traditional reinforcement learning algorithm(RL) with fixed strategies show that the active fault-tolerant controller designed in this paper can accurately and rapidly control under sensor faults so that the pressure of the OTSG can be stabilized near the set-point value, and the OTSG can run normally and stably.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1527-1534
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• 2016

Online voltage stability monitoring using real-time measurements is one of the most important tasks in a smart grid system to maintain the grid stability. Loading margin is a good indicator for assessing the voltage stability level. This paper presents an Extreme Learning Machine (ELM) approach for estimation of voltage stability level under credible contingencies using real-time measurements from Phasor Measurement Units (PMUs). PMUs enable a much higher data sampling rate and provide synchronized measurements of real-time phasors of voltages and currents. Depth First (DF) algorithm is used for optimally placing the PMUs. To make the ELM approach applicable for a large scale power system problem, Mutual information (MI)-based feature selection is proposed to achieve the dimensionality reduction. MI-based feature selection reduces the number of network input features which reduces the network training time and improves the generalization capability. Voltage magnitudes and phase angles received from PMUs are fed as inputs to the ELM model. IEEE 30-bus test system is considered for demonstrating the effectiveness of the proposed methodology for estimating the voltage stability level under various loading conditions considering single line contingencies. Simulation results validate the suitability of the technique for fast and accurate online voltage stability assessment using PMU data.

• ETRI Journal
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• 제31권4호
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• pp.419-428
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• 2009

A question answering (QA) system can be built using multiple QA modules that can individually serve as a QA system in and of themselves. This paper proposes a learnable, strategy-driven QA model that aims at enhancing both efficiency and effectiveness. A strategy is learned using a learning-based classification algorithm that determines the sequence of QA modules to be invoked and decides when to stop invoking additional modules. The learned strategy invokes the most suitable QA module for a given question and attempts to verify the answer by consulting other modules until the level of confidence reaches a threshold. In our experiments, our strategy learning approach obtained improvement over a simple routing approach by 10.5% in effectiveness and 27.2% in efficiency.

• Structural Engineering and Mechanics
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• 제81권5호
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• pp.647-664
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• 2022

The powerful data mapping capability of computational deep learning methods has been recently explored in academic works to develop strategies for structural health monitoring through appropriate characterization of dynamic responses. In many cases, these studies concern laboratory prototypes and finite element models to validate the proposed methodologies. Therefore, the present work aims to investigate the capability of a deep learning algorithm called Sparse Autoencoder (SAE) specifically focused on detecting structural alterations in real-case studies. The idea is to characterize the dynamic responses via SAE models and, subsequently, to detect the onset of abnormal behavior through the Shewhart T control chart, calculated with SAE extracted features. The anomaly detection approach is exemplified using data from the Z24 bridge, a classical benchmark, and data from the continuous monitoring of the San Vittore bell-tower, Italy. In both cases, the influence of temperature is also evaluated. The proposed approach achieved good performance, detecting structural changes even under temperature variations.