• 전산구조공학
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• 제17권3호
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• pp.7-13
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• 2004

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.529-536
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• 2016

In this paper we proposed an unsupervised algorithm to estimate the reverberation time (RT) directly from the reverberant speech signal. For estimation process we use maximum likelihood estimation (MLE) which is a very well-known and state of the art method for estimation in the field of signal processing. All existing RT estimation methods are based on the decay rate distribution. The decay rate can be obtained either from the energy envelop decay curve analysis of noise source when it is switch off or from decay curve of impulse response of an enclosure. The analysis of a pre-existing method of reverberation time estimation is the foundation of the proposed method. In one of the state of the art method, the reverberation decay is modeled as a Laplacian distribution. In this paper, the proposed method models the reverberation decay as a Gamma distribution along with the unification of an effective technique for spotting free decay in reverberant speech. Maximum likelihood estimation technique is then used to estimate the RT from the free decays. The method was motivated by our observation that the RT of a reverberant signal when falls in specific range, then the decay rate of the signal follows Gamma distribution. Experiments are carried out on different reverberant speech signal to measure the accuracy of the suggested method. The experimental results reveal that the proposed method performs better and the accuracy is high in comparison to the state of the art method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.412-415
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• 2005

Solar thermal power generation is one of promising and well-proven ways to convert solar energy to electricity. Though it requires high initial cost for system construction and continuous efforts for maintainment. it is more positive in terms of efficiency than other solar power generation technologies. Moreover, solar thermal power generation allows additional benefits of cheap thermal storage and easy hybridization with other fossil fuel-driven power generation. Owing to these benefits, large scale solar thermal power generation technology is expected to be competitive to other commercial technologies in the near future. In this paper an overview on the solar thermal hybrid power generation technology and the state of the art in Korea were briefly introduced.

• Journal of Information Technology Applications and Management
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• 제30권1호
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• pp.115-126
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• 2023

In various fields such as art, design, music, film, sports, games, and fashion, NFTs (Non-Fungible Tokens) are creating new economic value through trading platforms dedicated to NFT art and content. In this article, I analyze the current state of blockchain technology and NFT art content in the context of an expanding market for blockchain-based NFT art content in the metaverse. I also propose several tasks based on the economic and industrial logic of technological innovation. The first task proposed is to integrate cultural arts on blockchain, metaverse, and NFT platforms through digital innovation, instead of separating or distinguishing between creative production and consumption. Before the COVID-19 pandemic, there was a clear separation between creators and consumers. However, with the rise of Web 3.0 platforms, any user can now create and own their own content. Therefore, it is important to promote a collaborative and integrated approach to cultural arts production and consumption in the blockchain and metaverse ecosystem. The second task proposed is to align the legal framework with blockchain-based technological innovation. The enactment and revision of relevant laws should focus on promoting the development of the NFT trading platform ecosystem, rather than merely regulating it for user protection. As blockchain-based technology continues to evolve, it is important that legal systems adapt to support and promote innovation in the space. This shift in focus can help create a more conducive environment for the growth of blockchain-based NFT platforms. The third task proposed is to integrate education on digital arts, including metaverse and NFT art contents, into the current curriculum. This education should focus on convergence and consilience, rather than merely mixing together humanities, technology, and arts. By integrating digital arts education into the curriculum, students can gain a more comprehensive understanding of the potential of blockchain-based technologies and NFT art. This article examines the digital technological innovation such as blockchain, metaverse, and NFT from an economic and industrial point of view. As a limitation of this research, the critical mind such as philosophical thinking or social criticism on technological innovation is left as a future task.

• 한국정밀공학회지
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• 제13권7호
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• pp.45-58
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• 1996

We provide a set of information on technologies in the area of mechanical engineering to draw meaningful action plans for the internationalization of National R&D activities. In this study, we employed a modified Delphi method to evaluate levels of our technoligical capabilities and developed countries' as well. We investigate technology acquistion methodologies, technology charcteristics and various aspects of interna- tional cooperation in terms of technology. Then, we analyzed final responses of participants(i.e., the third round results of Delphi method) to see the correlation among various factors in developing mechanical engineeing technologies through international cooperation. The technology classification used in this research was devel- oped by STEPI(Science and Technology Policy Institute). In conclusion, our mechanical engineering technology is investigated to be below the middle level stage of technology(i.e., the stage of digesting acquired technologies) except the shipbuilding equipments technology which is evaluated to be on the top level stage of technology.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.226-232
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• 2000

Seismic probabilistic risk assessment(RA) rather than deterministic assessment provides more valuable information and insight for resolving seismic safety issues in nuclear power plant design. In the course of seismic PRA seismic fragility analysis is the most significant and essential phase especially for structural or mechanical engineers. Lately the seismic fragility analysis is taken as a useful tool in general structural engineering as well. A systemized and synthesized procedure or technology related to seismic fragility analysis of critical industrial facilities reflecting the unique experiences and database in Korea is urgently required. This paper gives a state-of-the-art reviews of PRA and briefly summarizes the technologies related to PRA and seismic fragility analysis before developing an unique technology considering characteristics of Korean database. Some key items to be resolved theoretically or technically are extracted and presented for the future research.

• Journal of Power Electronics
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• 제9권1호
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• pp.1-17
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• 2009

Permanent magnet brushless DC (PMBLDC) motors are the latest choice of researchers due to their high efficiency, silent operation, compact size, high reliability and low maintenance requirements. These motors are preferred for numerous applications; however, most of them require sensorless control of these motors. The operation of PMBLDC motors requires rotor-position sensing for controlling the winding currents. The sensorless control would need estimation of rotor position from the voltage and current signals, which are easily sensed. This paper presents state of the art PMBLDC motor drives with an emphasis on sensorless control of these motors.

• 한국전자파학회지:전자파기술
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• 제24권2호
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• pp.23-34
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• 2013

Over the past several decades in the microelectronics industry, devices have gotten smaller, thinner, and lighter, without any accompanying degradation in quality, performance, and reliability. One permanent and deniable trend in packaging as well as wafer fabrication industry is system integration. The proliferating options for system integration, recently, are driving change across the overall semiconductor industry, requiring more investment in developing, ramping and supporting new die-, wafer- and board-level solution. The trend toward 3D system integration and miniaturization in a small form factor has accelerated even more with the introduction of smartphones and tablets. In this paper, the key issues and state of the art for system integration in the packaging process are introduced, especially, focusing on ease transition to next generation packaging technologies like through silicon via (TSV), 3D wafer-level fan-out (WLFO), and chip-on-chip interconnection. In addition, effective solutions like fine pitch copper pillar and MEMS packaing of both advanced and legacy products are described with several examples.

• 한국해양공학회지
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• 제17권4호
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• pp.81-85
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• 2003

The industry has undergone a significant change over the last decade: digital business has become a strategy to survive; the extended enterprise is being implemented; parts are made where conditions are most favourable; non-core activities are out-sourced; advanced manufacturing systems and information technologies are introduced to improve manufacturing performance. Suppliers and distributors become part of the supply chain and they all comprise an integrated international co-operative network to provide manufactured goods and support services for a world market just in time, at low prices and with quality surpassing customers' expectations. In this paper, we review various state-of-the-art information technologies for the shipbuilding industry. The successful introduction and implementation of those technologies will be the key enabler for e-transformation in the shipbuilding industry.

• 융복합기술연구소 논문집
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• 제11권1호
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• pp.1-5
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• 2021

Deep learning based methods achieve state-of-the-art accuracy, however, they typically rely on supervised training with large labeled datasets. It is known in many medical applications that labeling medical images requires significant expertise and much time, and typical hand-tuned approaches for data augmentation fail to capture the complex variations in such images. This paper proposes a 3D image augmentation method to overcome these difficulties. It allows us to enrich diversity of training data samples that is essential in medical image segmentation tasks, thus reducing the data overfitting problem caused by the fact the scale of medical image dataset is typically smaller. Our numerical experiments demonstrate that the proposed approach provides significant improvements over state-of-the-art methods for 3D medical image segmentation.