• Journal of Information Processing Systems
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• 제13권5호
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• pp.1382-1396
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• 2017

In this paper, we analyze a recently proposed semi-fragile watermarking scheme based on local binary pattern (LBP) operators, and note that it has a fundamental flaw in the design. In this work, a binary watermark is embedded into image blocks by modifying the neighborhood pixels according to the LBP pattern. However, different image blocks might have the same LBP pattern, which can lead to false detection in watermark extraction process. In other words, one can modify the host image intentionally without affecting its watermark message. In addition, there is no encryption process before watermark embedding, which brings another potential security problem. To illustrate its weakness, two special copy-paste attacks are proposed in this paper, and several experiments are conducted to prove the effectiveness of these attacks. To solve these problems, an improved semi-fragile watermarking based on LBP operators is presented. In watermark embedding process, the central pixel value of each block is taken into account and Arnold transform is adopted to guarantee the security of watermark. Experimental results show that the improved watermarking scheme can overcome the above defects and locate the tampered region effectively.

• 한국멀티미디어학회논문지
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• 제24권10호
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• pp.1380-1390
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• 2021

The video face recognition (FR) is one of the most popular researches in the field of computer vision due to a variety of applications. In particular, research using the attention mechanism is being actively conducted. In video face recognition, attention represents where to focus on by using the input value of the whole or a specific region, or which frame to focus on when there are many frames. In this paper, we propose a novel attention based deep learning method. Main novelties of our method are (1) the use of combining two loss functions, namely weighted Softmax loss function and a Triplet loss function and (2) the feasibility of end-to-end learning which includes the feature embedding network and attention weight computation. The feature embedding network has a positive effect on the attention weight computation by using combined loss function and end-to-end learning. To demonstrate the effectiveness of our proposed method, extensive and comparative experiments have been carried out to evaluate our method on IJB-A dataset with their standard evaluation protocols. Our proposed method represented better or comparable recognition rate compared to other state-of-the-art video FR methods.

• Journal of Acupuncture Research
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• 제38권4호
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• pp.320-324
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• 2021

Lumbar spinal stenosis (LSS) is a common degenerative spinal condition that can have unpredictable improvement and worsening of symptoms which include low back pain, radiating pain, claudication, and degenerative lumbar scoliosis affecting quality of life. In this study, thread embedding acupuncture (TEA) was used as a conservative treatment for LSS in combination with complex Korean medicine treatments (acupuncture, herbal medicines, and physical therapy). The treatment was evaluated using the numerical rating scale, walking distance and duration, and inclination of radiological lumbar scoliosis according to antalgic posture. TEA was performed 27 times between June 8, 2020, and March 16, 2021. The patient showed improvement in numerical rating scale score from 7 to 2, pain-free walking distance from 10 m to 900 m, and scoliosis inclination following treatment. The findings of this study suggest that TEA may be helpful in the treatment of LSS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4443-4462
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• 2020

This paper proposes a new framework of reversible data hiding scheme for absolute moment truncation coding (AMBTC) compressed images. AMBTC-based RDH can be applied to optical remote sensing (ORS) image transmission, which achieves target region preservation and image compression simultaneously. Existing methods can be concluded as two types. In type I schemes, stego codes mimic the original AMBTC format where no file bloat occurs, yet the carried secret data is limited. Type II schemes utilize predication errors to recode quantity levels of AMBTC codes which achieves significant increase in embedding capacity. However, such recoding causes bloat inside stego format, which is not appropriate in mentioned ORS transmission. The proposed method is a novel type I RDH method which prevents bloat inside AMBTC stego codes with significant improvement in embedding capacity. The AMBTC compressed trios are grouped into two categories according to a given threshold. In smooth trio, the modified low quantity level is constructed by concatenating Huffman codes and secret bits. The reversible contrast mapping (RCM) is performed to complex trios for data embedment. Experiments show that the proposed scheme provides highest payload compared with existing type I methods. Meanwhile, no expansion inside stego codes is caused.

• Journal of information and communication convergence engineering
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• 제13권1호
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• pp.62-68
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• 2015

In this paper, we propose a watermarking method for protecting the ownership of three-dimensional (3D) content generated from depth and texture images. After selecting the target areas to preserve the watermark by depth-image-based rendering, the reference viewpoint image is moved right and left in the depth map until the maximum viewpoint change is obtained and the overlapped region is generated for marking space. The region is divided into four subparts and scanned. After applying discrete cosine transform, the watermarks are inserted. To extract the watermark, the viewpoint can be changed by referring to the viewpoint image and the corresponding depth image initially, before returning to the original viewpoint. The watermark embedding and extracting algorithm are based on quantization. The watermarked image is attacked by the methods of JPEG compression, blurring, sharpening, and salt-pepper noise.

• 정보처리학회논문지D
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• 제9D권5호
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• pp.925-930
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• 2002

워터마킹은 DRM(digital rights management)의 요소 기술로서 많은 연구가 진행되어 왔다. 하지만, 3D 신속 조형 기술(RP : rapid proto-typing)에 적용된 연구는 찾아보기 어렵다. 대부분의 연구가 텍스트 문서, 2D 이미지, 동영상, 음악 등의 컨텐츠에 한정되어 있다. RP 시스템은 다품종 소량 생산에 적합하고, 시제품을 제작하여 제품개발 초기 단계에서 설계상의 오류나 부적합한 요인을 조기에 발견하는 것이 가능한 까닭에 산업 현장에 많이 사용되고 있다. 본 논문은 3D 형상 모델을 가지고 있는 STL(stereolithography) 파일에 워터마크를 삽입하는 방법에 관한 연구이다. 제안된 알고리즘은 3D 형상 데이터의 법선 영역과 패싯 뒷면 영역에 워터마크를 삽입한다. 이런 까닭에 3D 형상에는 어떠한 왜곡도 발생하지 않으며 워터마크의 비가시성(invisibility)을 충족한다. 제안된 알고리즘으로 3D 형상 데이터의 법선 영역과 패싯 뒷면 영역에 워터마크 데이터의 삽입과 추출이 가능함을 보여주었으며, 본 연구의 실험 결과는 fragile 워터마킹과 robust 워터마킹과의 이용가능성을 제시하였다.

• 방송공학회논문지
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• 제24권6호
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• pp.1152-1162
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• 2019

VR 산업의 급격한 발전에 따라 많은 VR 콘텐츠들이 제작 및 유통되면서 저작권 보호에 대한 필요성이 높아지고 있다. 본 논문에서는 VR 제작과정을 고려하여 워터마크를 삽입 및 추출하는 방법을 제안한다. 삽입에서는 VR 제작에서 왜곡이 최소화되는 영역을 선택하여 SIFT를 수행하고 DWT를 이용하여 주파수로 변환하여 QIM방식으로 삽입한다. 추출에서는 투영 과정에서의 왜곡을 보정하기 위해 위와 아래영역은 투영방법을 변경하고, 중간영역 중 일부는 3DoF를 이용하여 회전을 수행한 후 워터마크를 추출한다. 이에 대해 기존의 워터마크 방법을 적용했을 때보다 높은 정확도를 가지며 다양한 공격에서도 정확도가 유지되는 것을 보임으로 제안한 워터마크의 유효함을 확인한다.

• Restorative Dentistry and Endodontics
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• 제9권1호
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• pp.7-14
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• 1983

The purpose of this study was to investigate pulpal responses to tricalcium phosphate and durapatite which recently introduced as a bone substitute. Tricalcium phosphate and durapatite were placed on the amputated pulp tissue in the dog's teeth. Animals were sacrificed after 1, 2, 3 and 4 weeks and specimens were decalcified, embedding, sectioned and stained routinly. Microscopic examination reveals as follows; 1. Tricalcium phosphate: Severe inflammatory change was seen in the all cases and calcified masses were seen at 2 weeks. Calcified masses were enlarged according to the time elapsed. 2. Durapatite: Severe inflammatory change and pus cavities were found at 1 week. There was no evidence of healthy cell component in the remaining pulp tissue and degenerative change was obvious at 2, 3 and 4 weeks. 3. Dentin bridge was not formed in the both cases. In the case of tricalcium phosphate osteoblasts were observed unevenly around the calcified masses which were composed of hematophilic substance in central portion and eosinophilic substance in peripheral region of the masses.

• 스마트미디어저널
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• 제9권3호
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• pp.9-17
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• 2020

Hippocampus is a complex brain structure embedded deep into the temporal lobe. Studies have shown that this structure gets affected by neurological and psychiatric disorders and it is a significant landmark for diagnosing neurodegenerative diseases. Hippocampus features play very significant roles in region-of-interest based analysis for disease diagnosis and prognosis. In this study, we have attempted to learn the embeddings of this important biomarker. As conventional metric learning methods for feature embedding is known to lacking in capturing semantic similarity among the data under study, we have trained deep Siamese convolutional neural network for learning metric of the hippocampus. We have exploited Gwangju Alzheimer's and Related Dementia cohort data set in our study. The input to the network was pairs of three-view patches (TVPs) of size 32 × 32 × 3. The positive samples were taken from the vicinity of a specified landmark for the hippocampus and negative samples were taken from random locations of the brain excluding hippocampi regions. We have achieved 98.72% accuracy in verifying hippocampus TVPs.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.18-21
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• 2007

Digital image watermarking is a technology used in copyrighting of digital images by embedding unremovable informations. In this paper, a pixel-domain look-up-table-based watermarking algorithm is presented. With this methodology, the watermark was embedded in the host image, but we did not observe any distortion at certain specific region of interest. This means the proposed method is preferred in case of satellite images. Then, the image manipulation tool which is called 'StirMark' will be used to perform many kinds of attacks such as rotation, scaling, filtering and compression on the watermarked image. Finally, the effectiveness of a watermarking technique in terms of 'robustness' and 'data integrity' criteria will be measured by calculating PSNR of watermark and watermarked image.