• Journal of Korea Society of Industrial Information Systems
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• v.19 no.6
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• pp.87-96
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• 2014

Since markup is defined as price over marginal cost by Hall(1988), the New Keynesians have intensively applied its definition in elucidating the relationship between market structure and business cycle. In lots of literatures markups proved to be counter cyclical empirically and theoretically. At the same time many studies analysed the determinants for markup in relation with business cycles. This paper establishes the markup equation based on the constant returns to scale production function including intermediate goods with technology being assumed to be AR(1) process and estimates the industrial markups in the Korean 5 service industries over the period 1975:1-2010:4. The paper also analyzed the markup determinants using the autoregressive distributed lag scheme ADL(1,1) in which the dependent variable and the single explanatory variable are each lagged once.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.221-231
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• 2017

The purpose of this study was to investigate the relationship between traditional media communication, new media communication, lovemarks, satisfaction, and behavioral intention in foodservice industry. As the results of study as followed. First, traditional media communication had a significant effect on love dimension, but no significant effect on respect dimension of lovemarks. Second, new media communication had a significant effect on love and respect dimension. Third, love and respect dimension of lovemarks had a significant effect on satisfaction and behavior intention respectively, also satisfaction had a significant effect on behavior intention. Fourth, as a result of the indirect effect analysis of the research model, the traditional media and new media communication had a significant effect on satisfaction through lovemarks, and a significant effect on the behavior intention through lovemarks and satisfaction. This result shows that the enhancement of consumer's communication experience and lovemarks recognition can promote post-purchase behavior such as satisfaction with brand and behavioral intention.

• The Journal of Society for e-Business Studies
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• v.15 no.4
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• pp.181-195
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• 2010

The participation and share between personal users are the driving force of Web 2.0, and easily found in blog, social network, collective intelligence, social bookmarking and tagging. Among those applications, the social bookmarking lets Internet users to store bookmarks online and share them, and provides various services based on shared bookmarks which people think important.Delicious.com is the representative site of social bookmarking services, and provides a bookmark search service by using tags which users attach to the bookmarks. Our paper suggests a method re-ranking the ranks from Delicious.com based on user tags in order to provide personalized bookmark recommendations. Moreover, a method to consider bookmarks which have tags not directly related to the user query keywords is suggested by using tag network based on Jaccard similarity coefficient. The performance of suggested system is verified with experiments that compare the ranks by Delicious.com with new ranks of our system.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.122-128
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• 2015

As multimedia information is spread over cyber networks, problems such as protection of legal rights and original proof of an information owner raise recently. Various image transformations of DCT, DFT and DWT have been used to embed a watermark as a token of ownership. Recently, SVD being used in the field of numerical analysis is additionally applied to the watermarking methods. A watermarking method is proposed in this paper using Gabor cosine and sine transform as well as SVD for embedding and extraction of watermarks for digital images. After delivering attacks such as noise addition, space transformation, filtering and compression on watermarked images, watermark extraction algorithm is performed using the proposed GCST-SVD method. Normalized correlation values are calculated to measure the similarity between embedded watermark and extracted one as the index of watermark performance. Also visual inspection for the extracted watermark images has been done. Watermark images are inserted into the lowest vertical ac frequency band. From the experimental results, the proposed watermarking method using the singular vectors of SVD shows large correlation values of 0.9 or more and visual features of an embedded watermark for various attacks.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.503-510
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• 2020

In this paper, we proposed an effective technique that greatly improves the security of the watermark by concealing the multiple-encrypted watermark in the LSB of the image pixel. Even if multiple encrypted watermark hidden in the LSBs of an image pixel are extracted, it is impossible to decrypt them, so the security of the watermark is maintained very high. If the watermark is multiple encrypted and hidden in the image using the proposed technique, the visual quality of the watermark-hidden image is very high, making it impossible to distinguish between the original image and the resulting image in which the watermark is hidden. The original watermark data can be completely extracted without loss, according to the procedure of the proposed technique, from the resulting image that the watermark is encrypted and hidden in the original image. The performance of the proposed technique was analyzed mathematically and the superiority of the proposed technique was confirmed through experiments. The proposed technique is an excellent image watermarking technique that greatly improves the security of the watermark hidden in the image compared to the existing technique.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.455-462
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• 2001

The World Wide Web has become one of the major services provided through Internet. When searching the vast web space, users use bookmarking facilities to record the sites of interests encountered during the course of navigation. One of the typical problems arising from bookmarking is that the list of bookmarks lose coherent organization when the the becomes too lengthy, thus ceasing to function as a practical finding aid. In order to maintain the bookmark file in an efficient, organized manner, the user has to classify all the bookmarks newly added to the file, and update the folders. This paper introduces our learning agent called BClassifier that automatically classifies bookmarks by analyzing the contents of the corresponding web documents. The chief source for the training examples are the bookmarks already classified into several bookmark folders according to their subject by the user. Additionally, the web pages found under top categories of Yahoo site are collected and included in the training examples for diversifying the subject categories to be represented, and the training examples for these categories as well. Our agent employs naive Bayesian learning method that is a well-tested, probability-based categorizing technique. In this paper, the outcome of some experimentation is also outlined and evaluated. A comparison of naive Bayesian learning method alongside other learning methods such as k-Nearest Neighbor and TFIDF is also presented.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.685-688
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• 2006

본 논문에서는 기존의 DCT(Discrete Cosine Transform)를 이용한 디지털 워터마킹 방법을 개선하여 비가시성을 향상시키는 DCT 기반의 디지털 워터마킹 방법을 제안하고자 한다. 이에 원 영상을 DCT 변환한 영역에 워터마크로 사용할 이미지를 이진화하여 얻은 픽셀 값을 기준으로 워터마크를 삽입하고자 한다. 삽입 할 워터마크는 식별하기 어려운 의사난수를 사용하지 않고 가시적으로 인지할 수 있는 문자(서명) 혹은 도장으로 구성된 이진 영상을 사용한다. 이 방법의 강인성 평가를 위해 워터마크가 삽입된 영상을 대상으로 영상처리를 수행하지 않은 경우, JPEG 영상압축, cropping, 필터링, 밝기 조절 및 대비 확장 등 기본적인 영상처리 알고리즘을 적용한 후 워터마크를 검출하였다. 실험 결과 제안된 방법의 워터마킹 영상은 기존 방법에 비하여 워터마크가 삽입된 영상의 화질이 비교적 우수하였으며 검출된 워터마크의 시각적인 인지도가 높아 가시적 효율성이 뛰어남을 검증하였다. 최종적으로, 실험에 의해 제안한 방법의 유용성을 입증하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2001.11b
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• pp.175-179
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• 2001

본 논문에서는 디지털 오디오 데이터에 부가 정보를 삽입하는 기술로써 계층적 워터마크를 사용하여 시간 변형을 감지할 수 있고, 필요에 따라 검출 복잡도를 조절할 수 있는 기법을 제안한다. 1계층 워터마크는 오디오 데이터의 시간축 변형을 감지할 수 있도록 오디오 데이터의 반향을 이용하고, 2계층 워터마크는 1계층 워터마크된 오디오 데이터를 기준으로 대역 확산 기법을 이용하여 저작권 정보 등의 요구량이 많은 부가 정보를 삽입한다. 이 때, 2계층 워터마크는 프레임의 동기 확보를 위한 동기 수열, 부가 정보 삽입을 위한 데이터 수열, 두 개를 이용한다. 검출기에서는 시스템의 요구 사항에 따라 1계층, 2계층 전단계, 2계층 본 단계 등의 계층적 순서로 검출할 수 있으며, 각 계층은 데이터에 가해진 변형 정도를 추정하여 다음 계층의 검출단에 정보를 제공한다. 여러 가지 실험 결과를 통하여 제안한 방식이 다양한 신호 처리에 강인함을 보였다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.32-36
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• 2009

본 논문에서는 DCT영역에서 반복적 이진위상컴퓨터형성홀로그램을 이용한 디지털 영상 워터마킹 기술을 제안하였다. 워터마크로 주로 사용되는 랜덤 시퀸스 또는 로고와 같은 은닉영상 대신 은닉영상을 손실없이 재생할 수 있는 이진위상컴퓨터형성홀로그램을 생성하고, 이를 반복적으로 표현해서 워터마크로 사용한다. 그리고 이 워터마크를 호스트영상의 DCT 계수에 적절한 규칙을 통해 가중치를 부여하여 삽입한 후, IDCT한다. 워터마크의 추출은 워터마킹된 영상과 호스트영상을 DCT하고, 삽입시 적용한 규칙을 통해서 수행한다. 그리고 추출된 워터마크의 역푸리에 변환과 호스트영상에 삽입하기전의 워터마크를 역푸리에 변환하여 재생한 은닉영상과의 상관을 취함으로써 워터마크의 존재여부를 검증한다. 제안한 방법은 워터마크 삽입/추출시 반복되는 홀로그램정보를 활용하고, 이진 값으로 구성되어 있으므로 기존의 어떠한 워터마킹 기술보다 외부 공격에 견실한 특징을 가지고 있으며, 컴퓨터 시뮬레이션을 통해 그 성능을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.875-878
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• 2001

본 논문에서는 디지털 영상의 변조를 확인함과 동시에 변조의 위치를 확인하는 연성 워터마킹(fragile watermarking)을 위하여 DCT를 통해 블록의 에너지를 계산한 후, 에너지의 단계별로 워터마크의 삽입량을 조절하는 방법을 제안한다. 디지털 영상의 소유권 확인을 위해 디지털 서명을 사용하며, 영상에 DCT를 수행함으로서 모든 픽셀에 워터마크를 삽입하지 않고서도 변조의 유무를 확인하는 것이 가능하 방식이다. DCT 계수로 각 블록의 에너지를 계산하여 블록의 관계를 분류하며 에너지가 작은 블록들과 큰 블록들은 이간의 시각에 민감한 부분이므로 워터마크의 삽입 양을 줄이고, 중간 단계의 블록일수록 워터마크의 삽입 양을 늘린다. 에너지의 단계 분류에 의해 가변적으로 워터마크를 삽입함으로 워터마크의 비가시성과 연성을 만족시키며 변조의 유무와 위치를 확인할 수 있게 된다.