• The Journal of the Acoustical Society of Korea
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• v.32 no.5
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• pp.415-422
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• 2013

This paper proposes a robust binary audio fingerprinting method by minimizing hinge-loss function. In the proposed method, the type of fingerprints is binary, which is conducive in reducing the size of fingerprint DB. In general, the binarization of features for fingerprinting deteriorates the performance of fingerprinting system, such as robustness and discriminability. Thus it is necessary to minimize such performance loss. Since the similarity between two audio clips is represented by a hinge-like function, we propose a method to derive a binary fingerprinting by minimizing a hinge-loss function. The derived hinge-loss function is minimized by using the minimal loss hashing. Experiments over thousands of songs demonstrate that the identification performance of binary fingerprinting can be improved by minimizing the proposed hinge loss function.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.664-666
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• 2002

기울기 연산자나 표면접합에 의한 윤곽추출과는 다른 본 논문에서는 확장과 수축방법론을 이용한 윤곽추출 및 잡음제거 방법론을 제안한다. 제안한 알고리즘은 전처리과정을 거친 후 확장과 수축 방법론을 적용함으로써 영상 윤곽 추출률을 높이고자한다 특히, 기존의 윤곽선 추출방법인 소벨과 프리위트알고리즘은 전처리과정인 미디안필터를 거친 후에 사용하였으며, 제안한 방법은 기존의 윤곽선 추출 필터를 거친 후에 사용하였다. 구체적으로 서술하면 확장알고리즘에서는 일정한 임계치를 초과하면 흰색으로 대치하였고, 수축 알고리즘에서는 검정색으로 대치했다. 기존의 잡음제거과정은 윤곽선의 손실은 없었으나 잡음제거가 소량 이루어졌으며, 제안한 방법에서는 약간의 윤곽선 손실을 보였으나 완전하게 잡음을 제거시킬 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.27-36
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• 2006

Lossless data embedding is a method to insert information into a host image that guarantees complete restoration when the extraction has been done. In this paper, we propose a noble reversible data embedding algorithm for images in wavelet domain. The proposed embedding technique, which modifies histogram of wavelet coefficient, is composed of two inserting steps. Data is embedded to wavelet coefficient using modification of histogram in first embedding process. Second embedding step compensates the distortion caused by the first embedding process as well as hides more information. Hence we achieve higher inserting capacity. In view of the relationship between the embedding capacity and the PSNR value, our proposed method shows considerably higher performance than the current reversible data embedding methods.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.86-89
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• 2011

현재 인터넷이 생활의 일부로 자리함으로써 인터넷을 통해 수많은 멀티미디어의 교환이 발생하며, 많은 멀티미디어 서비스가 이루어지고 있다. 멀티미디어 서비스를 제공함에 있어 최근 저작권 관리 및 보호의 필요성이 대두되고 있다. 이에 따라 멀티미디어 데이터에 대한 암호기술 개발에 많은 연구가 진행되고 있으며 카오스 사상에 기반 한 암호화 연구가 최근 연구 추세이다. 본 논문은 MPEG(Moving Picture Experts Group) 인코딩 과정에서 1차원 카오스 사상(Map)을 이용하여 인트라 블록을 암호화하는 새로운 방법을 제안하고자 한다. 본 제안 시스템은 MPEG 구조 기반으로 CKD(Chaotic Key Distributor)를 이용하여 확장된 키 값으로 인트라 블록의 0이 아닌 DCT(Discrete Cosine Transform) 계수를 암호화 하는 방법이다. MPEG 인코딩 과정중 DCT 계수는 양자화를 통해 손실이 발생하더라도 비교적 많은 0값을 생성한다. 이는 RLE(Run Length Encoding) 과정에서 압축 효과를 높일 수 있다. 제안하는 방법은 영상 손실을 감수하고 수행한 양자화 과정의 효과를 유지하기 위하여 0이 아닌 DCT 계수만을 암호화 한다. 실험 결과 원본과 암호화된 MPEG의 크기의 변화는 매우 적으며, 인코딩 시간 또한 큰 차이를 보이지 않았다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.108-108
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• 2020

본 연구에서는 관측자료를 이용하여 제주도 한천 유역의 침투 특성을 파악하고자 하였다. 이를 위해 2012년부터 2019년까지 제주도 한천 유역의 주요 호우사상을 선정하고 한천 하류부의 위치한 제2동산교 지점의 유출량 자료를 이용하였다. 먼저 호우사상별 유출량 자료를 이용하여 유효우량(또는 유출고) 산정하고 초기손실을 결정하였다. 다음으로 유효우량과 초기손실을 NRCS CN 방법에 적용하여 최대잠재보유수량과 CN을 산정하였다. 산정된 호우사상별 CN 및 초기손실을 검토하기 위해 선행일수에 따른 선행강우량과 유출량과의 관계와 강우-유출 과정의 각 요소 간의 관계를 확인하였다. 마지막으로 초기손실, 최대잠재보유수량, CN 등 각 요소들의 분포와 이상치를 확인하여 제주도 한천 유역의 적절한 CN 및 초기손실의 규모를 검토하였으며, 그 결과, 제주도 한천 유역의 적절한 초기손실, 최대잠재보유수량, α, 지체시간의 규모는 각각 30 mm~40 mm, 170 mm~190 mm, 0.20~0.23, 50~60, 60 min~90 min으로 나타났다.

• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.778-789
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• 2021

Recently, various lightweight methods for using Convolutional Neural Network(CNN) models in mobile devices have emerged. Weight quantization, which lowers bit precision of weights, is a lightweight method that enables a model to be used through integer calculation in a mobile environment where GPU acceleration is unable. Weight quantization has already been used in various models as a lightweight method to reduce computational complexity and model size with a small loss of accuracy. Considering the size of memory and computing speed as well as the storage size of the device and the limited network environment, this paper proposes a method of compressing integer weights after quantization using a video codec as a method. To verify the performance of the proposed method, experiments were conducted on VGG16, Resnet50, and Resnet18 models trained with ImageNet and Places365 datasets. As a result, loss of accuracy less than 2% and high compression efficiency were achieved in various models. In addition, as a result of comparison with similar compression methods, it was verified that the compression efficiency was more than doubled.

• KOREAN POULTRY JOURNAL
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• v.11 no.5 s.115
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• pp.54-58
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• 1979

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.8 no.4
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• pp.260-265
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• 1979

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.525-534
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• 2001

Generally, compression and encryption procedures are performed independently in lossless image compression and encryption. When compression is followed by encryption, the compressed-stream should have the property of randomness because its entropy is decreased during the compression. However, when full data is compressed using image compression methods and then encrypted by encryption algorithms, real-time processing is unrealistic due to the time delay involved. In this paper, we propose to combine compression and encryption to reduce the overall processing time. It is method decomposing gray-scale image by means of quadtree compression algorithms and encrypting the structural part. Moreover, the lossless compression ratio can be increased using a transform that provides an decorrelated image and homogeneous region, and the encryption security can be improved using a reconstruction of the unencrypted quadtree data at each level. We confirmed the increased compression ratio, improved encryption security, and real-time processing by using computer simulations.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.2
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• pp.73-78
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• 2010

Wave energy is dissipated mainly by friction on the seabed until the waves reach the surf zone. Many researchers have investigated the mechanism of wave friction and the bottom shear stress induced by wave motion at a certain point is now well estimated by introducing the wave friction factor related to the near bed velocity given by linear wave theory. The variation of wave energy or wave height over a long distance can be, however, estimated by an iteration process when the propagation of waves is strongly influenced by bed friction. In the present study simple semi-theoretical equation has been developed to compute the variation of wave height for the condition of wave propagation on a constant beach slope. The ratio of wave height is determined by the product of shoalng factor and wave height friction factor (frictional wave energy dissipation factor). The wave height estimated by the new equation is compared with the wave height estimated by the solution of numerical integration for the condition that the waves propagate on a constant slope.