• KIPS Transactions on Computer and Communication Systems
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• v.10 no.10
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• pp.269-276
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• 2021

Recently, smart sensors are used in various environments, and the implementation of ad-hoc sensor networks (ASNs) is a hot research topic. Unfortunately, traditional sensor network routing algorithms focus on specific control issues, and they can't be directly applied to the ASN operation. In this paper, we propose a new routing protocol by using the Q-learning technology, Main challenge of proposed approach is to extend the life of ASNs through efficient energy allocation while obtaining the balanced system performance. The proposed method enhances the Q-learning effect by considering various environmental factors. When a transmission fails, node penalty is accumulated to increase the successful communication probability. Especially, each node stores the Q value of the adjacent node in its own Q table. Every time a data transfer is executed, the Q values are updated and accumulated to learn to select the optimal routing route. Simulation results confirm that the proposed method can choose an energy-efficient routing path, and gets an excellent network performance compared with the existing ASN routing protocols.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.89-89
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• 2022

하천 합류부에 지천이 유입되는 경우 복잡한 3차원적 흐름 구조를 발생시키고 이로 인해 유사혼합 및 지형 변화가 활발히 발생하게 된다. 특히, 하천 합류부에서 부유사 거동은 하천의 세굴과퇴적, 하천 지형 변화, 하천 생태계, 하천구조물 안정성 등에 직접적으로 영향을 미치기 때문에 이에 대한 정확한 분석이 하천 관리 및 재해 예방에 필수적인 요소이다. 기존의 하천 합류부 부유사 계측 자료들은 재래식 채취 방식으로 수행되어 시공간적 해상도가 매우 낮아서 실측 자료만으로 합류부에서 부유사 혼합을 분석하기에는 한계가 존재하기에 대하천의 부유사 혼합 거동 해석에 수치모형이 주로 활용되어 왔다. 본 연구에서는 하천 합류부에서 부유사 거동을 공간적으로 정밀하게 분석하기 위해 드론 기반초분광 영상을 활용하여 하천 합류부에 최적화된 부유사 계측 방법론을 제시하였다. 현장에서 계측한 초분광 자료와 부유사 농도간의 관계를 구축하기 위하여 기계학습모형인 랜덤포레스트(Random Forest) 회귀 모형과 합류부에서 분광 특성이 다른 두 하천의 특성을 정확하게 반영하기 위한 가우시안 혼합 모형 (Gaussian Mixture Model) 기반 초분광 군집화 기법을 결합하였다. 본 연구에서 구축한 방법론을 낙동강과 황강의 합류부에 적용한 결과, 초분광 군집을 통해 두하천 흐름의 경계층을 명확히 구별하였으며, 이를 바탕으로 지류와 본류에 대해 각각 분리된 회귀 모형을 구축하여 복잡한 합류부 근역 경계층에서의 부유사 거동을 보다 정확하게 재현하였다. 또한 나아가서 재현된 고해상도의 부유사 공간분포를 바탕으로 경계층에서 강한 두 흐름이 혼합되어 발생한 와류(Wake)가 부유사 혼합에 미치는 영향을 규명하였고, 하천 합류부에서 발생하는 전단층의 수평방향 대규모 와류가 부유사 혼합 양상에 지배적 영향을 미치는 것으로 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.303-306
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• 2021

이미지 초해상도는 영상 취득 과정에서 센서와 렌즈의 물리적인 한계 등으로 인하여 의해 화질이 저하된 이미지를 더 높은 배율로 복원하는 문제이다. 이미지 초해상도는 딥러닝을 통해 놀라운 성능향상을 이루었지만, 카메라로 촬영된 실제 이미지에서는 좋은 성능을 내지 못하였다. 이는 딥러닝에서는 'bicubic' 커널로 down-sampling된 합성 이미지 데이터를 사용하였던 것과 달리 실제 이미지에서는 'bicubic' 커널을 통한 화질 저하와는 다른 화질 저하, 즉 다른 커널을 통한 화질 저하가 발생하기 때문이다. 따라서 실제 이미지에 대한 성능을 높이기 위해서는 이에 대한 정확한 커널 예측이 필요하다. 최근 주목받기 시작한 이미지 초해상도를 위한 커널 예측은 초해상도를 잘 시켜주는 커널을 직접 찾는 방법[10, 13]과 이미지의 분포와 커널을 통해 다운샘플된 이미지에 대한 분포를 일치시켜주면서 커널을 예측하는 방법[14]으로 나누어져 있다. 그러나 두 방법 모두 ill-posed problem 인 커널 예측 문제를 한 장의 이미지만으로 해결하려는 것이기 때문에 정확한 예측에는 어려움이 발생한다. 따라서 본 논문에서는 두 장의 이미지를 활용한 이미지 화질 저하 커널 예측 방법을 제안한다. 제안된 방법은 두 장의 이미지가 같은 카메라를 통해 촬영되었으며 이때 이미지 화질 저하는 카메라에 의해서만 영향을 받는다는 가정을 기반으로 한다. 즉, 두 장의 이미지는 같은 커널을 통해 저하된 이미지라는 가정을 한다. 제안된 방법은 [14]에서처럼 이미지 분포를 기반으로 한 커널 예측을 진행하며, 이미지 초해상도를 진행하고자 하는 이미지 외에 참고 이미지 또한 같은 커널에서 화질 저하를 시켰을 때 본래의 이미지와 같은 분포에 있도록 학습을 진행한다. 결과적으로 본 논문에서는 두 장의 이미지를 사용하였을 때 더욱 정확하게 커널을 찾을 수 있음을 보여준다. 두 장의 이미지를 활용하는 방식이 한 장의 이미지만을 활용하는 기존의 최고 수준의 방법에 비해 합성된 다양한 커널 데이터셋[14]에서 약 0.17dB 성능 향상이 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.277-280
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• 2021

Recently as various contents are mass produced based on high accessibility, the media contents market is more active. Users want to find content that suits their taste, and each platform is competing for personalized recommendations for content. For an efficient recommendation system, high-quality metadata is required. Existing platforms take a method in which the user directly inputs the metadata of an image. This will waste time and money processing large amounts of data. In this paper, for media hyperpersonalization recommendation, keyframes are extracted based on the YCrCb color model of the video based on movie trailers, movie genres are distinguished through supervised learning of artificial intelligence and In the future, we would like to propose a utilization plan for generating metadata.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.557-561
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• 2021

A meatadata has become an essential element in order to recommend video content to users. However, it is passively generated by video content providers. In the paper, a method for automatically generating metadata was studied in the existing manual metadata input method. In addition to the method of extracting emotion tags in the previous study, a study was conducted on a method for automatically generating metadata for genre and country of production through movie audio. The genre was extracted from the audio spectrogram using the ResNet34 artificial neural network model, a transfer learning model, and the language of the speaker in the movie was detected through speech recognition. Through this, it was possible to confirm the possibility of automatically generating metadata through artificial intelligence.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.197-205
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• 2020

Korean language has the characteristics that the pronunciation of phoneme units such as vowels and consonants are fixed and the pronunciation associated with a notation does not change, so that foreign learners can approach rather easily Korean language. However, when one pronounces words, phrases, or sentences, the pronunciation changes in a manner of a wide variation and complexity at the boundaries of syllables, and the association of notation and pronunciation does not hold any more. Consequently, it is very difficult for foreign learners to study Korean standard pronunciations. Despite these difficulties, it is believed that systematic analysis of pronunciation errors for Korean words is possible according to the advantageous observations that the relationship between Korean notations and pronunciations can be described as a set of firm rules without exceptions unlike other languages including English. In this paper, we propose a visualization framework which shows the differences between standard pronunciations and erratic ones as quantitative measures on the computer screen. Previous researches only show color representation and 3D graphics of speech properties, or an animated view of changing shapes of lips and mouth cavity. Moreover, the features used in the analysis are only point data such as the average of a speech range. In this study, we propose a method which can directly use the time-series data instead of using summary or distorted data. This was realized by using the deep learning-based technique which combines Self-organizing map, variational autoencoder model, and Markov model, and we achieved a superior performance enhancement compared to the method using the point-based data.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.39-57
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• 2021

In this study, mathematical analysis is conducted by focusing to the 'size' of the 'point' and the 'line'. The textbook descriptions of the 'point' and the 'line' in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum and US geometry textbooks were compared and analyzed between. First, as a result of mathematical analysis of' 'the size of a point and a segment', it was found that the mathematical perspectives could be different according to 1) the size of a point is based on the recognition and exclusion of 'infinitesimal', and 2) the size of the segment is based on the 'measure theory' and 'set theory'. Second, as a result of analyzing textbook descriptions of the 'point' and the 'line', 1) in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum, after presenting a learning activity that draws a point with 'physical size' or line, it was developed in a way that describes the 'relationship' between points and lines, but 2) most of the US geometry textbooks introduce points and lines as 'undefined terms' and explicitly states that 'points have no size' and 'lines have no thickness'. Since the description of points and lines in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum may potentially generate mathematical intuitions that do not correspond to the perspective of Euclid geometry, this study suggest that attention is needed in the learning process about points and lines.

• Journal of Practical Engineering Education
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• v.11 no.1
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• pp.1-8
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• 2019

Virtual Training is an educational exercise in which the environment or the situation is virtually implemented for specific training and proceed like a real situation. In recent years, the virtual reality technology has developed rapidly, and the demand for experiencing situation that are not directly experienced in the real world is increasing more and more in virtual reality. Particularly, there is an increasing demand of contents for hands-on training and virtual training for equipment training that replaces high-risk and high-cost industry training. The virtual training contents have been developed and utilized for the purpose of technical training. However, it is known that virtual training is more effective when it is used as a supplementary training material or combined with e-learning contents rather than replacing one training course with virtual training contents because purpose and effect are different from general technical training course. In this study, we explored the development method for effective utilization of electrohydraulic servo control process, which is the virtual reality contents developed in 2017 in combination with e-learning contents. In addition, in order to establish a teaching and learning strategy, we actually develop and operate a case studies using virtual training contents. Surveys and case studies are conducted to investigate the effects of teaching and learning strategies applied in the classroom on students and their educational usefulness.

• 지역과문화
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• v.6 no.1
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• pp.1-27
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• 2019

The study explores the way how sharing economy services of accommodation and car rental, one of social issues actively discussed today are settled in the process of sharing economy building in local destinations. The result shows that average consumers expressed their favorable attitude toward the sharing economy services. However, the consumer's attitude didn't directly affect the consumer's positive perception that there is need for local sharing economy service network and the educational system for local residents and the network helps the economy. Instead consumer's knowledge of sharing economy services and their eagerness to learn the knowledge as parameters related the consumer's attitude to their perceptions; the consumer's attitude affected indirectly their perceptions. The study shows that local communities and their residents' efforts are not enough simply to activate the sharing economy services in the development process of tourist resources, while it asks consumers to learn information and knowledge of the sharing economy. Therefore, consumers and residents should interact and communicate closely with each other to help the development of local destinations and tourist resources based on sharing economy.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.2
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• pp.24-33
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• 2022

The travel notes and nature poems found in historic literary men's works can be considered historical records related to scenic sites. Such travel notes and nature poems are based on the writers' personal characters, experiences, learning and etc. Such works clearly show the characters of each literature, information of the related objects and the writers' thoughts of the objects. This study, thus, looked into Euisang on Xīsāishān Mountain that could be the origin of Eobusa(漁父詞) loved and sung by Korean historic literary men, and found that the Korean and Chinese literary men's thoughts were shown through their ways to enjoy Xīsāishān Mountain and their Euisang on the mountain, which was different between the Korean and Chinese literary men depending on the geographical locations described in their poems. In detail, the study results are: 1. Such difference of the ways to enjoy Xīsāishān Mountain, the scenic site described in historic Korean and Chinese literary men's work is broadly classified into the ways to enjoy the scenic site by seeing it in person and the ways to enjoy it under the mental structure of speculation. 2. Xīsāishān Mountain in Wuxing is the background of Yújiāzi(漁家子) of the painting Zhāngzhìhé, is boasting its distinguished beautiful nature, and is the place where the Confucian Study of Hú(湖學) was originated. It is also the place known of its warmhearted climate. Therefore, Euisang on Xīsāishān Mountain under such beautiful and warmhearted circumstance are realized as the complete freedom and seclusion in Taoism and the satisfaction with the given environment and position in Confucianism. 3. Xīsāishān Mountain in Wǔchāng is a military strategic point with rugged mountain terrain and scenery that has been a historic ferocious battlefield and related with the loyal civil servant Qū Yuán. The Euisang on Xīsāishān Mountain in Wǔchāng, therefore, represents the nature scenery of a rugged fortress and patriotism of Confucianism. 4. The Korean literary men's way to enjoy Xīsāishān Mountain is Shinyu(神遊: spiritual travel), so that their Euisang is formed according to the direction of the writer's values. Especially it is noted that Korean Euisang on Xīsāishān Mountain is originally based on the painting Zhāngzhìhé that shows the complete free mood of Taoism; and the Euisang on Xīsāishān Mountain that came from the mindful image by the poet monk Qíjǐ of Tang dynasty and Kim Si-seup appears with such Buddhist ways to seek the truth as SakGongIlYeo(色空一如: Being full is essentially as same as being vacant) and GyeonSeongSeongBul(見性成佛: Everybody can become Buddha by enlightenment).