• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.257-260
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• 2020

본 논문은 단일의 옷감 이미지로 가상의 그래픽 렌더링을 위해 Pix2Pix 방법을 이용하여 Normal map 을 생성하는 방법을 제시한다. 구체적으로 단일의 이미지를 이용해서 Normal map 를 생성하기 위해, Color image 와 Normal map 쌍의 training dataset 을 Pix2Pix 방법을 이용해서 학습시킨다 또한, test dataset 의 Color image 를 입력으로 넣어 생성된 Normal map 결과를 확인한다. 그리고 선행연구에서 사용되어오던 U-Net 방식의 방법과 본 논문에서 사용한 Pix2Pix 를 이용한 Normal map 생성 결과를 SSIM(Structural Similarity Index)으로 비교 평가한다. 또한, 생성된 Normal map 을 렌더링하고자 하는 가상 객체의 사이즈에 맞게 사이즈를 조정하여 OpenGL 로 렌더링한 결과를 확인한다. 본 논문을 통해서 단일의 패턴 이미지를 Pix2Pix 로 생성한 Normal map 으로 옷감의 디테일을 사실감 있게 표현할 수 있음을 확인할 수 있었다.

• Journal of the Korean Mathematical Society
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• v.35 no.1
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• pp.237-257
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• 1998

By introducing the notion of a generalized normal state space, we give a necessary and sufficient condition for that there exists a unital normal completely map from a von Neumann algebra into another, in terms of their generalized normal state spaces.

• Honam Mathematical Journal
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• v.35 no.4
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• pp.765-773
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• 2013

We show that for the logistic map, almost every x is a normal number mod 2 with respect to all intervals except for $[a,b]=[\frac{1}{4},1]\;or\;[a,b]=[\frac{1}{2}-\frac{\sqrt{3}}{4},\frac{1}{2}+\frac{\sqrt{3}}{4}]$.

• Communications of the Korean Mathematical Society
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• v.14 no.1
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• pp.189-200
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• 1999

In this paper, we proved that the only surfaces of 1-type Gauss map with flat normal connection are spheres, products of two plane circles and helical cylinders.

• Journal of Broadcast Engineering
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• v.27 no.1
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• pp.69-79
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• 2022

In this study, a method of generating and utilizing a normal map image used to represent the characteristics of the surface of an image material to improve the classification accuracy of the original material image is proposed. First of all, (1) to generate a normal map that reflects the surface properties of a material in an image, a U-Net with attention-R2 gate as a generator was used, and a Pix2Pix-based method using the generated normal map and the similarity with the original normal map as a reconstruction loss was used. Next, (2) we propose a network that can improve the accuracy of classification of the original material image by applying the previously created normal map image to the attention gate of the classification network. For normal maps generated using Pixar Dataset, the similarity between normal maps corresponding to ground truth is evaluated. In this case, the results of reconstruction loss function applied differently according to the similarity metrics are compared. In addition, for evaluation of material image classification, it was confirmed that the proposed method based on MINC-2500 and FMD datasets and comparative experiments in previous studies could be more accurately distinguished. The method proposed in this paper is expected to be the basis for various image processing and network construction that can identify substances within an image.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.01a
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• pp.203-205
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• 2020

본 논문에서는 게임 엔진에서 사용되는 노말맵(Normal Map)의 원리와 그 응용 방식에 대해 연구하였다. 노말맵은 게임에서 하이 폴리곤 모델링에 적용되는 조명 적용 데이터를 로우 폴리곤에 적용할 수 있는 기술로, 하이 폴리곤 모델링의 벡터 방향 데이터를 텍스쳐로 저장하여 로우 폴리곤에 적용해서 벡터 방향을 텍셀단위로 조정할 수 있게 한다. 여기에서는 게임에서의 노말맵 저장 방식과 연산 방식에 대해 소개하고 이를 응용하여 최적화 시킬 수 있는 방법에 대해 연구한다.

• Bulletin of the Korean Mathematical Society
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• v.52 no.1
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• pp.301-312
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• 2015

In this paper, we study a class of spacelike rotational surfaces in the Minkowski 4-space $\mathbb{E}^4_1$ with meridian curves lying in 2-dimensional spacelike planes and having pointwise 1-type Gauss map. We obtain all such surfaces with pointwise 1-type Gauss map of the first kind. Then we prove that the spacelike rotational surface with flat normal bundle and pointwise 1-type Gauss map of the second kind is an open part of a spacelike 2-plane in $\mathbb{E}^4_1$.

• Bulletin of the Korean Mathematical Society
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• v.49 no.1
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• pp.57-61
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• 2012

It is well known that one could use a fixed loxodromic or parabolic element of a non-elementary group $G{\subset}M(\bar{\mathbb{R}}^n)$ as a test map to test the discreteness of G. In this paper, we show that a test map need not be in G. We also construct an example to show that the similar result using an elliptic element as a test map does not hold.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3780-3797
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• 2022

The estimation of radio map (RM) is a fundamental and critical task for the network planning and optimization performance of mobile communication. In this paper, a RM estimation method is proposed based on a deep dual learning structure. This method can simultaneously and accurately reconstruct the urban building map (UBM) and estimate the RM of the whole cell by only part of the measured reference signal receiving power (RSRP). Our proposed method implements UBM reconstruction task and RM estimation task by constructing a dual U-Net-based structure, which is named RadioCycle. RadioCycle jointly trains two symmetric generators of the dual structure. Further, to solve the problem of interference negative transfer in generators trained jointly for two different tasks, RadioCycle introduces a dynamic weighted averaging method to dynamically balance the learning rate of these two generators in the joint training. Eventually, the experiments demonstrate that on the UBM reconstruction task, RadioCycle achieves an F1 score of 0.950, and on the RM estimation task, RadioCycle achieves a root mean square error of 0.069. Therefore, RadioCycle can estimate both the RM and the UBM in a cell with measured RSRP for only 20% of the whole cell.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.38-45
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• 1998

The Z-map model which is quite similar to the non-parametric patch is widely used to describe the shape of a surface because of its simplicity. Despite the inherent advantage of z-map model. it has drawbacks that there exists difficulty in expressing the vertical walls and its related contact treatment method. In the region of vertical walls, there is a convergence problem in searching the contact point. In this study a contact point finding scheme is presented, based on the z value of the z-map model on the sheet normal direction. To show the utility of this scheme a compared with the experimental results. The effects of the Z-map grid distances and the interpolations of the inside Z-map value are also discussed.