• 실천공학교육논문지
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• 제14권1호
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• pp.99-108
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• 2022

최근에 늘어가는 키오스크(KIOSK)의 수요에 따라 불편함을 호소하는 이용자가 많아졌다. 이에 음성 기반 대화형 서비스를 구현하여 손쉽게 메뉴 선택 및 주문을 가능하게 해주는 키오스크를 제작해 웹의 형태로 제공한다. Annyang API와 SpeechSynthesis API를 바탕으로 음성 기능을 구현하고 Dialogflow를 통해 사용자의 의도를 파악하는 과정을 Rest API를 기반으로 구현하는 방법에 대해 논한다. 또한 협업 필터링을 기반으로 추천 시스템을 적용하여 기존 키오스크의 낮은 소비자 접근성을 개선하였고, 음성인식 서비스 이용 도중 발생하는 비말로 인한 감염을 예방하기 위해 서비스 이용 전 마스크 착용을 확인하는 기능을 제공한다.

• Educational Technology International
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• 제12권1호
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• pp.47-66
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• 2011

This study examines strategies and obstacles encountered in infusing digital resources in the middle school mathematics and science classroom. It draws on data from principals, technology coordinators and math and science teachers in three urban middle schools in United States. All three of these schools have recently invested heavily in technology hardware and high speed Internet connectivity and as such they provide an opportunity to look beyond well documented obstacles such as outdated computers and poor Internet access. The logistical, preparatory, pedagogical and curricular challenges encountered by teachers within the study have important implications for professional development efforts aimed at improving science education through the integration of Web-based resources.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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• pp.34-38
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• 2010

아직 국내에는 대용량 분산전원의 계통연계에 대한 기술기준 및 체계적인 선로운영 기술기준이 미흡하다. 본 논문에서는 배전계통 모의시험장치 및 분산전원 모의실험 장치를 구성하고, 실시간 전압/전류 데이터를 수집/분석하기 위하여 LabVIEW 감시제어장치를 설치하여, 태양광정원의 정상상태에서의 전압특성을 분석하였다. 태양광전원의 출력변동(역 조류)에 의한 계통의 전압변동과 역률변동 특성에 대한 시험을 수행하여 계통연계시의 문제점을 분석하고, 대책방안을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2726-2732
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• 2014

The promoting effect of rhodium on the structure and activity of the supported Cu-Co based catalysts for CO hydrogenation was investigated in detail. The samples were characterized by DRIFTS, $N_2$-adsorption, XRD, $H_2$-TPR, $H_2$-TPD and XPS. The results indicated that the introduction of rhodium to Cu-Co catalysts resulted in modification of metal dispersion, reducibility and crystal structure. DRIFTS results of CO hydrogenation at reaction condition (P=2 MPa, $T=260^{\circ}C$) indicated the addition of 1 wt % rhodium improved hydrogenation ability of Cu-Co catalysts. The ethanol selectivity and CO conversion were both improved by 1 wt % Rh promoted Cu-Co based catalysts. The alcohol distribution over un-promoted and rhodium promoted Cu-Co based catalysts obeys A-S-F rule and higher chain growth probability was got on rhodium promoted catalyst.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.694-706
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• 2019

In this study, we applied the long short-term memory (LSTM) model to classify the cryptocurrency price time series. We collected historic cryptocurrency price time series data and preprocessed them in order to make them clean for use as train and target data. After such preprocessing, the price time series data were systematically encoded into the three-dimensional price tensor representing the past price changes of cryptocurrencies. We also presented our LSTM model structure as well as how to use such price tensor as input data of the LSTM model. In particular, a grid search-based k-fold cross-validation technique was applied to find the most suitable LSTM model parameters. Lastly, through the comparison of the f1-score values, our study showed that the LSTM model outperforms the gradient boosting model, a general machine learning model known to have relatively good prediction performance, for the time series classification of the cryptocurrency price trend. With the LSTM model, we got a performance improvement of about 7% compared to using the GB model.

• 실천공학교육논문지
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• 제10권1호
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• pp.57-62
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• 2018

평생직업개발에 대한 중요성 인식, MOOC의 확산과 온라인 교육에 대한 관심이 증대되면서 평생직업능력개발을 위한 교육 시스템 마련을 위한 노력이 계속되고 있으나 기술공학분야의 역량기반 평가 도구와 시스템에 대한 설계 개발에 대한 연구는 미진한 실정이다. 이에, 본 논문에서는 평생직업능력개발을 위한 기술공학분야의 직무역량을 평가하기 위한 시스템(Competence-based Assessment System for Lifelong Vocational Competency Development : CBAS-LVCD)을 설계 및 구축하였다. CBAS-LVCD는 NCS 기반 루브릭 평가 도구를 사용하여 학습자를 평가하고 기술공학분야에서 사용할 시뮬레이션 도구를 제공한다. 이는 실습과 온라인 시험이 제한적인 기술 엔지니어링 분야의 실무에 필요한 역량을 평가하는 데 큰 도움이 될 것으로 기대된다.

• Current Optics and Photonics
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• 제7권4호
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• pp.463-470
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• 2023

Hydroxygraphene as a kind of functionalized graphene has important applications in composite, photoelectric and biological materials. In the present study, THz and microfluidic technologies were implemented to study the THz transmission characteristics of hydroxygraphene with different concentrations and residence times in magnetic and electric fields. The results show that the THz transmission intensity decreases with the increase in sample concentration and duration of an applied electric field, while it increases by staying longer in the magnetic field. The phenomenon is analyzed and explained in terms of hydrogen bond, conductivity and scattering characteristics. The results establish a foundation for future research on the THz absorption characteristics of liquid graphene based on microfluidic technology in different external environments. It also provides technical support for the application and development of graphene in THz devices.

• Journal of Information Processing Systems
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• 제4권4호
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• pp.159-168
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• 2008

Human-Robot Interaction (HRI), based on already well-researched Human-Computer Interaction (HCI), has been under vigorous scrutiny since recent developments in robot technology. Robots may be more successful in establishing common ground in project-based education or foreign language learning for children than in traditional media. Backed by its strong IT environment and advances in robot technology, Korea has developed the world's first available e-Learning home robot. This has demonstrated the potential for robots to be used as a new educational media - robot-learning, referred to as 'r-Learning'. Robot technology is expected to become more interactive and user-friendly than computers. Also, robots can exhibit various forms of communication such as gestures, motions and facial expressions. This study compared the effects of non-computer based (NCB) media (using a book with audiotape) and Web-Based Instruction (WBI), with the effects of Home Robot-Assisted Learning (HRL) for children. The robot gestured and spoke in English, and children could touch its monitor if it did not recognize their voice command. Compared to other learning programs, the HRL was superior in promoting and improving children's concentration, interest, and academic achievement. In addition, the children felt that a home robot was friendlier than other types of instructional media. The HRL group had longer concentration spans than the other groups, and the p-value demonstrated a significant difference in concentration among the groups. In regard to the children's interest in learning, the HRL group showed the highest level of interest, the NCB group and the WBI group came next in order. Also, academic achievement was the highest in the HRL group, followed by the WBI group and the NCB group respectively. However, a significant difference was also found in the children's academic achievement among the groups. These results suggest that home robots are more effective as regards children's learning concentration, learning interest and academic achievement than other types of instructional media (such as: books with audiotape and WBI) for English as a foreign language.

• Smart Structures and Systems
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• 제31권3호
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• pp.247-257
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• 2023

In structural health monitoring of large-scale structures, optimal sensor placement plays an important role because of the high cost of sensors and their supporting instruments, as well as the burden of data transmission and storage. In this study, a vibration sensor placement algorithm based on deep reinforcement learning (DRL) is proposed, which can effectively solve non-convex, high-dimensional, and discrete combinatorial sensor placement optimization problems. An objective function is constructed to estimate the quality of a specific vibration sensor placement scheme according to the modal assurance criterion (MAC). Using this objective function, a DRL-based algorithm is presented to determine the optimal vibration sensor placement scheme. Subsequently, we transform the sensor optimal placement process into a Markov decision process and employ a DRL-based optimization algorithm to maximize the objective function for optimal sensor placement. To illustrate the applicability of the proposed method, two examples are presented: a 10-story braced frame and a sea-crossing bridge model. A comparison study is also performed with a genetic algorithm and particle swarm algorithm. The proposed DRL-based algorithm can effectively solve the discrete combinatorial optimization problem for vibration sensor placements and can produce superior performance compared with the other two existing methods.

• 문화기술의 융합
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• 제5권2호
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• pp.375-380
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• 2019

본 논문의 핵심 주제는 개방형 교육 플랫폼 기반 학습 프로세스 마이닝 및 애널리틱스 기술로 최근에 관심과 사용이 급속히 증가하고 있는 MOOC(Massive Open Online Courseware) 등과 같은 개방형 교육 플랫폼을 기반으로 하는 개인별 학습 이력 로그로부터 학습 및 러닝 프로세스를 중심으로 하는 유의미한 학습 프로세스 지식을 발견하고 분석하기 위한 학습 프로세스 마이닝 프레임워크를 설계 및 구현하는 기술이다. 러한 프레임워크의 핵심 기술로서, 학습 프로세스의 표현, 추출, 분석, 가시화하는 기술과 이러한 마이닝 및 분석된 학습 프로세스 지식으로부터 개선된 학습 프로세스 관련 교육 서비스를 제공하는 기술로 구성된다.