• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.223-228
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• 2009

Efficient service discovery mechanism is a crucial feature for a hybrid ad-hoc network supporting extension of a wireless ad-hoc network to the Internet. We propose an efficient cross-layer service discovery mechanism using non-disjoint multi-path source routing protocol for hybrid ad-hoc networks. Our scheme has advantages of multi-path routing protocol and cross-layer service discovery. Intuitively, it is not difficult to imagine that the cross-layer service discovery mechanism could result in a decreased number of messages compared to the traditional approach for handling routing independently from service discovery. By simulation, we show that faster route recovery is possible by maintaining multiple routing paths in each node, and the route maintenance overhead can be reduced by limiting the number of multiple routing paths and by maintaining link/node non-disjoint multi-path.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.892-895
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• 2018

본 논문에서는 키넥트(kinect)의 인체 추적 기능을 사용하여 다중 레이어 기능을 제공하는 제스처 인식 기반 드로잉 시스템을 설계 구현하였다. 제안된 드로잉 시스템은 제스처를 통해 자유롭게 그림을 그릴 수 있는 시스템으로 그림을 그리는 붓의 굵기 선택, 지우개를 이용한 그림 지우기, 사물을 이용한 물감색 선택, 템플릿을 이용한 그림그리기 등을 수행하는 다양한 제스처가 정의 되어 있고, 제스처를 이용하여 화면에 자유롭게 그림을 그릴 수 있도록 함으로써 사용자의 몰입감과 흥미를 높일 수 있도록 설계 구현되었다. 제안 시스템은 원하는 템플릿을 이용하여 색칠하기를 수행하는 템플릿 기반 드로잉 레이어와 템플릿 없이 자유롭게 그림을 그리는 프리 드로잉 레이어를 지원함으로써 다양한 그림 그리기가 가능하도록 구현되었다.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.427-428
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• 2015

정보통신 기술의 발전으로 교육 패러다임이 스마트 디바이스를 이용하는 스마트 러닝으로 변화하고 있다. 특히 에듀테인먼트 시스템들은 암묵적 지식습득률 향상을 위하여 증강현실 기술을 도입한 다양한 시스템들이 도입되고 있다. 그러나 이와 같이 증강현실을 이용한 시스템들은 실환경의 조명과 가상환경의 조명환경의 부조화로 인하여 영상 합성시 실감성이 낮은 문제점을 가지고 있다. 따라서 본 논문에서는 증강 객체, 웹캠을 통해 입력된 영상, 가상의 배경 영역으로 구성된 단일 레이어를 3차원 조명환경 정보를 포함한 블록 레이어로 변환하고 변환된 블록 레이어를 합성하는 에듀테인먼트를 위한 증강현실 시스템을 설계한다.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.97-103
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• 2010

In this paper, we present an efficient design scheme based on analysis of design requirements and considerations of baseband packet switch for S-band satellite/terrestrial hybrid multi-beam satellite communication systems. To establish design requirements and considerations, we analyze required functions of baseband packet switch, specifications of multi-beam satellite communications, communication services and performance requirements. And also we analyze and compare conventional layer-2 and layer-3 satellite baseband packet switching techniques, packet switching protocols and packet switch architectures, to apply from analyzed results. Finally, we propose a hardware design scheme of MPEG based layer-2 baseband packet switch using analyzed results.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.540-543
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• 2020

기존의 초해상도 딥러닝 기법은 모델의 깊이가 깊어지면서, 좋은 성능을 내지만 점점 더 복잡해지고 있고, 실제로 사용하는데 있어 많은 시간을 요구한다. 이를 해결하기 위해, 우리는 딥러닝 모델의 가중치를 양자화 하여 추론시간을 줄이고자 한다. 초해상도 모델은 feature extraction, non-linear mapping, reconstruction 세 부분으로 나누어져 있으며, 레이어 사이에 많은 skip-connection 이 존재하는 특징이 있다. 따라서 양자화 시 최종 성능 하락에 미치는 영향력이 레이어 별로 다르며, 이를 감안하여 강화학습으로 레이어 별 최적 bit 를 찾아 성능 하락을 최소화한다. 본 논문에서는 Skip-connection 이 많이 존재하는 MSRN 을 사용하였으며, 결과에서 feature extraction, reconstruction 부분과 블록 내 특정 위치의 레이어가 항상 높은 bit 를 가짐을 알 수 있다. 기존에 영상 분류에 한정되어 사용되었던 혼합 bit 양자화를 사용하여 초해상도 딥러닝 기법의 모델 사이즈를 줄인 최초의 논문이며, 제안 방법은 모바일 등 제한된 환경에 적용 가능할 것으로 생각된다.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.38-47
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• 2013

An image coding based on MRC model, a kind of multi-layer image model, first segments a screen image into foreground, mask, and background layers, and then compresses each layer using a codec that is suitable to the layer. The mask layer defines the position of foreground regions such as textual and graphical contents. The colour signal of the foreground (background) region is saved in the foreground (background) layer. The mask layer which contains the segmentation result of foreground and background regions is of importance since its accuracy directly affects the overall coding performance of the codec. This paper proposes a new layer segmentation algorithm for the MRC based image coding. The proposed method extracts text pixels from the background using morphological top hat filtering. The application of white or black top hat transformation to local blocks is controlled by the information of relative brightness of text compared to the background. In the proposed method, the boundary information of text that is extracted from the edge map of the block is used for the robust decision on the relative brightness of text. Simulation results show that the proposed method is superior to the conventional methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.123-127
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• 2012

Since the propagation of computers and Internet along with proliferation of smartphones rise, a large amount of data is being produced and modified daily. As the usage of data soars, a way of securely storing data emerged as a new problem. In this paper, saving big-data by using hierarchical data structure with multi-layer form, to come up with new security file format and API by applying encryption on each layers, is introduced. Moreover, we expect to see shown file format in this paper to be used in various fields.

• Journal of Broadcast Engineering
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• v.18 no.5
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• pp.722-729
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• 2013

For low contrast images, a histogram equalization is possible to easily identify information when the intensity is concentrated in an image. Over contrast enhancement is the problem of generating an unnatural image cognitively because the focus of existing techniques was the contrast enhancement. In order to solve this problem, CLAHE method solves unnatural problems by limiting contrast using a maximum threshold. However, this method has an extra problem that concealed detail information in an image. This paper proposes a detail-map based on the multiple layers block overlapped histogram equalization in order to avoid loss of detail information. Loss of detail information has been made to minimize as combining images with limited contrast enhancement using a detail-map in each layers.

• Journal of Broadcast Engineering
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• v.23 no.4
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• pp.474-483
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• 2018

In this paper, we propose a multi-scale high dynamic range (HDR) tone mapping algorithm using guided image filter (GIF). The GIF is used to divide an image into a base layer and a detail layer, then the range of the detail layer is reduced with a compression function to enhance the detail information of the image. However, in most cases, an image includes the detail and edge information in different scales. That is to say, it is difficult to represent all detail features under a certain scale, and a single-scale image decomposition method is not free from artifacts around edges. To solve the problems, the multi-scale image decomposition method is proposed. It utilizes the detail layers of several scale to determine how much edge is preserved. Experiment results show that the proposed algorithm has better image performance in preserving edge compared to conventional algorithm.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.45-65
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• 2013

A design file can get larger in size as the complexity of the target object increases. A large design file may reside in a large parallel computing system, such as cloud computing systems, and many designers may work concurrently on the same design file. In such a case, it is obvious that we need some kind of protection mechanism so that each user can access only the area of the file he or she is entitled to. Two approaches can be taken for this problem: one is the traditional access control mechanisms and the other encryption techniques. We take the latter approach to ensure the safety of the file even in public domain such as clouding systems, and in this paper, we suggest an encryption scheme for a file where the file is encrypted in multi-layer so that each user is allowed to access the file only at the layer for which the user has the proper access right. Each layer of the file is encrypted with different keys and these keys are exposed only to those who have the right access permit. The paper explains the necessary file format to achieve this goal and discusses the file manipulation functions to handle this new file format.