• 천문학회보
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• 제44권1호
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• pp.81.2-81.2
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• 2019

We develop an image-to-image translation model, which is a popular deep learning method based on conditional Generative Adversarial Networks (cGANs), to generate solar magnetograms and EUV images from sunspot drawings. For this, we train the model using pairs of sunspot drawings from Mount Wilson Observatory (MWO) and their corresponding SDO/HMI magnetograms and SDO/AIA EUV images (512 by 512) from January 2012 to September 2014. We test the model by comparing pairs of actual SDO images (magnetogram and EUV images) and the corresponding AI-generated ones from October to December in 2014. Our results show that bipolar structures and coronal loop structures of AI-generated images are consistent with those of the original ones. We find that their unsigned magnetic fluxes well correlate with those of the original ones with a good correlation coefficient of 0.86. We also obtain pixel-to-pixel correlations EUV images and AI-generated ones. The average correlations of 92 test samples for several SDO lines are very good: 0.88 for AIA 211, 0.87 for AIA 1600 and 0.93 for AIA 1700. These facts imply that AI-generated EUV images quite similar to AIA ones. Applying this model to the Galileo sunspot drawings in 1612, we generate HMI-like magnetograms and AIA-like EUV images of the sunspots. This application will be used to generate solar images using historical sunspot drawings.

• 천문학회보
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• 제44권1호
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• pp.82.3-82.3
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• 2019

In this study, we generate future full disk magnetograms in 12, 24, 36 and 48 hours advance from SDO/HMI images using deep learning. To perform this generation, we apply the convolutional generative adversarial network (cGAN) algorithm to a series of SDO/HMI magnetograms. We use SDO/HMI data from 2011 to 2016 for training four models. The models make AI-generated images for 2017 HMI data and compare them with the actual HMI magnetograms for evaluation. The AI-generated images by each model are very similar to the actual images. The average correlation coefficient between the two images for about 600 data sets are about 0.85 for four models. We are examining hundreds of active regions for more detail comparison. In the future we will use pix2pix HD and video2video translation networks for image prediction.

• 한국정보통신학회논문지
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• 제26권9호
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• pp.1305-1311
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• 2022

최근 모바일 단말기 및 개인형 컴퓨터의 비약적인 발전과 신경망 기술의 등장으로 영상을 활용한 실시간 안면 교체가 가능해졌다. 특히, 순환 적대적 생성 신경망은 상호 연관성이 없는 이미지 데이터를 활용한 안면 교체가 가능하게 만들었다. 본 논문에서는 적은 학습 데이터와 시간으로 안면 교체의 품질을 높일 수 있는 입력 데이터 처리 기법을 제안한다. 제안 방식은 사전에 학습된 신경망을 통해서 추출된 안면의 특이점 정보와 안면의 구조와 표정에 영향을 미치는 주요 이미지 정보를 결합함으로써 안면 표정과 구조를 보존하면서 이미지 품질을 향상시킬 수 있다. 인공지능 기반의 무참조 품질 메트릭 중의 하나인 blind/referenceless image spatial quality evaluator (BRISQUE) 점수를 활용하여 제안 방식의 성능을 정량적으로 분석하고 기존 방식과 비교한다. 성능 분석 결과에 따르면 제안 방식은 기존 방식 대비 약 4.6%~14.6% 개선된 BRISQUE 점수를 나타내었다.

• 한국군사과학기술학회지
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• 제25권5호
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• pp.476-486
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• 2022

Synthetic dynamic infrared image generation from the given virtual environment is being the primary goal to simulate the output of the infra-red(IR) camera installed on a vehicle to evaluate the control algorithm for various search & reconnaissance missions. Due to the difficulty to obtain actual IR data in complex environments, Artificial intelligence(AI) has been used recently in the field of image data generation. In this paper, CycleGAN technique is applied to obtain a more realistic synthetic IR image. We added the Structural Similarity Index Measure(SSIM) loss function to the L1 loss function to generate a more realistic synthetic IR image when the CycleGAN image is generated. From the simulation, it is applicable to the guided-missile flight simulation tests by using the synthetic infrared image generated by the proposed technique.

• Journal of Information Technology Applications and Management
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• 제31권4호
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• pp.139-148
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• 2024

This study takes a comprehensive look at how technological advances have changed the way 2D animation is created. Humans are constantly looking for new ways and technologies to express movement, which has led to many changes in the way 2D animation is produced. In this study, we will examine the impact of these changes on 2D animation production and explore the possibilities for future developments. In the early days of 2D animation, the production method was repeatedly changed by the invention of technologies such as celluloid sheets, rotoscopes, and multiplane cameras, while the advent of digital technology has led to revolutionary changes such as the development of CAPS(computer animation production systems), various digital tools, and the combination of 2D and 3D. In addition, the recent introduction of generative AI is rapidly changing the way 2D animation is produced by automatically handling various tasks. These advances have not only streamlined the production of animation, but have also reduced costs by shortening the production period, and greatly improved the quality of animation by making it easier to implement complex and sophisticated visual effects. The introduction of generative AI has pushed the boundaries of what can be represented in 2D animation. On the other hand, the introduction of digital technology has its drawbacks, as the mechanical and uniform style produced by digital tools can reduce originality and individuality, but advances in technology will open up the possibilities for 2D animation to be produced in a variety of ways, as it fosters the creation of new expressions and creative content.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.617-619
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• 2018

본 논문에서는 계층형 적대적 생성 신경망(GAN: Generative Adversarial Network)에서 오류 판별자를 추가하여 영상 생성 성능을 개선하는 방안을 제안한다. 제안하는 영상 생성 방법에서는 영상 생성자가 빈번히 발생시키는 오류에 대해 별도로 학습을 수행하는 판별자를 모델에 추가하여 계층형 적대적 생성 신경망을 구성하였다. 본 논문에서 제안한 모델을 이용하여 생성한 영상의 효용성을 검증하는 방법으로는 Inception Score를 사용하였다. 학습 데이터로 celebA의 유명인 얼굴 이미지 중 정면 이미지 155,680장을 이용하였다. 본 논문의 모델로 생성한 10,000장의 얼굴 이미지를 Inception Score로 평가한 결과, 평균 1.742p의 성능을 나타내어 기존의 영상 생성 방법보다 높은 점수를 얻을 수 있었으며, 효용성을 확인할 수 있었다.

• 천문학회보
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• 제46권1호
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• pp.41.2-41.2
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• 2021

In this study, we generate He I 1083 nm images from Solar Dynamic Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images using a novel deep learning method (pix2pixHD) based on conditional Generative Adversarial Networks (cGAN). He I 1083 nm images from National Solar Observatory (NSO)/Synoptic Optical Long-term Investigations of the Sun (SOLIS) are used as target data. We make three models: single input SDO/AIA 19.3 nm image for Model I, single input 30.4 nm image for Model II, and double input (19.3 and 30.4 nm) images for Model III. We use data from 2010 October to 2015 July except for June and December for training and the remaining one for test. Major results of our study are as follows. First, the models successfully generate He I 1083 nm images with high correlations. Second, the model with two input images shows better results than those with one input image in terms of metrics such as correlation coefficient (CC) and root mean squared error (RMSE). CC and RMSE between real and AI-generated ones for the model III with 4 by 4 binnings are 0.84 and 11.80, respectively. Third, AI-generated images show well observational features such as active regions, filaments, and coronal holes. This work is meaningful in that our model can produce He I 1083 nm images with higher cadence without data gaps, which would be useful for studying the time evolution of chromosphere and coronal holes.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2022년도 제66차 하계학술대회논문집 30권2호
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• pp.145-147
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• 2022

본 논문에서는 훼손되어 식별할 수 없는 탑 이미지를 비롯해 낮은 해상도의 탑 이미지를 개선하기 위해 우리는 탑 이미지의 화질 개선을 인공지능을 이용하여 빠르게 개선을 해 보고자 한다. 최근에 Generative Adversarial Networks(GANS) 알고리즘에서 SrGAN 알고리즘이 나오면서 이미지 생성, 이미지 복원, 해상도 변화 분야가 지속해서 발전하고 있다. 이에 본 연구에서는 다양한 GAN 알고리즘을 화질 개선에 적용해 보았다. 탑 이미지에 GAN 알고리즘 중 SrGan을 적용하였으며 실험한 결과 Srgan 알고리즘은 학습이 진행되었으며, 낮은 해상도의 탑 이미지가 높은 해상도, 초고해상도 이미지가 생성되는 것을 확인했다.

• Korean Journal of Radiology
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• 제24권11호
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• pp.1061-1080
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• 2023

Artificial intelligence (AI) in radiology is a rapidly developing field with several prospective clinical studies demonstrating its benefits in clinical practice. In 2022, the Korean Society of Radiology held a forum to discuss the challenges and drawbacks in AI development and implementation. Various barriers hinder the successful application and widespread adoption of AI in radiology, such as limited annotated data, data privacy and security, data heterogeneity, imbalanced data, model interpretability, overfitting, and integration with clinical workflows. In this review, some of the various possible solutions to these challenges are presented and discussed; these include training with longitudinal and multimodal datasets, dense training with multitask learning and multimodal learning, self-supervised contrastive learning, various image modifications and syntheses using generative models, explainable AI, causal learning, federated learning with large data models, and digital twins.

• 천문학회보
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• 제44권1호
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• pp.51.2-51.2
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• 2019

Multi-wavelength observations become very popular in astronomy. Even though there are some correlations among different sensor images, it is not easy to translate from one to the other one. In this study, we apply a deep learning method for image-to-image translation, based on conditional generative adversarial networks (cGANs), to solar images. To examine the validity of the method for scientific data, we consider several different types of pairs: (1) Generation of SDO/EUV images from SDO/HMI magnetograms, (2) Generation of backside magnetograms from STEREO/EUVI images, (3) Generation of EUV & X-ray images from Carrington sunspot drawing, and (4) Generation of solar magnetograms from Ca II images. It is very impressive that AI-generated ones are quite consistent with actual ones. In addition, we apply the convolution neural network to the forecast of solar flares and find that our method is better than the conventional method. Our study also shows that the forecast of solar proton flux profiles using Long and Short Term Memory method is better than the autoregressive method. We will discuss several applications of these methodologies for scientific research.