• The KIPS Transactions:PartB
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• v.13B no.6 s.109
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• pp.607-614
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• 2006

In this paper, we propose an error resilience video coder which uses a hybrid error concealment algorithm. Firstly, the algorithm uses the error concealment with data hiding. If the hiding information is lost, the motion vector of lost macroblock is computed with adaptive selection of adjacent motion vectors and OBMC (Overlapped Block Motion Compensation) is applied with this motion vector. We know our algorithm is more effective in case of continuous GOB. The results show more significant improvement than many temporal concealment methods such as MVRI (Motion Vector Rational Interpolation) or existing error concealment using data hiding.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2007.02a
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• pp.87-90
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• 2007

기존의 Steganography는 정보를 숨김에 있어 히스토그램을 shifting 하거나 픽셀간의 상관관계를 변형하는 등 다양한 방식이 제안되었다. 그런 논문들이 가지고 있던 용량적 한계를 일부 극복하고, PSNR을 고려하여 새로운 방식을 제안한다. 소개하는 기술은 두 색깔을 파트너로 맺어, 숨김 비트에 따라 서로 파트너로 바뀌도록 설계되었다. 숨긴 용량의 크기와PSNR의 변화를 실험 결과에서 볼 수 있으며, 이는 기존 논문과의 비교를 통해 효율성이 입증된다.

• Korean Journal of Cognitive Science
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• v.35 no.1
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• pp.49-95
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• 2024

Polygraph examination, statement validity analysis and P300-based concealed information test are major three examination tools, which are use to determine a person's truthfulness and credibility in criminal procedure. Although polygraph examination is most common in criminal procedure, but it has little admissibility of evidence due to the weakness of scientific basis. In 1990s to support the weakness of scientific basis about polygraph, Farwell and Donchin proposed the P300-based concealed information test technique. The P300-based concealed information test has two strong points. First, the P300-based concealed information test is easy to conduct with polygraph. Second, the P300-based concealed information test has plentiful scientific basis. Nevertheless, the utilization of P300-based concealed information test is infrequent, because of the quantity of probe stimulus. The probe stimulus contains closed information that is relevant to the crime or other investigated situation. In tradition P300-based concealed information test protocol, three or more probe stimuli are necessarily needed. But it is hard to acquire three or more probe stimuli, because most of the crime relevant information is opened in investigative situation. In addition, P300-based concealed information test uses oddball paradigm, and oddball paradigm makes imbalance between the number of probe and irrelevant stimulus. Thus, there is a possibility that the unbalanced number of probe and irrelevant stimulus caused systematic underestimation of P300 amplitude of irrelevant stimuli. To overcome the these two limitation of P300-based concealed information test, one-probe P300-based concealed information test protocol is explored with various machine learning algorithms. According to this study, parameters of the modified one-probe protocol are as follows. In the condition of female and male face stimuli, the duration of stimuli are encouraged 400ms, the repetition of stimuli are encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. In the condition of two-syllable word stimulus, the duration of stimulus is encouraged 300ms, the repetition of stimulus is encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. It was also conformed that the logistic regression (LR), linear discriminant analysis (LDA), K Neighbors (KNN) algorithms were probable methods for analysis of P300 amplitude. The one-probe P300-based concealed information test with machine learning protocol is helpful to increase utilization of P300-based concealed information test, and supports to determine a person's truthfulness and credibility with the polygraph examination in criminal procedure.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.143-150
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• 2003

Error concealment plays an important role in combating transmission errors. Methods of error concealment which produce better quality are generally of higher complexity, thus making some of the more sophisticated algorithms is not suitable for real-time applications. In this paper, we develop temporal and spatial error resilient video encoding and data hiding approach to facilitate the error concealment at the decoder. Block interleaving scheme is introduced to isolate erroneous blocks caused by packet losses for spatial area of error resilience. For temporal area of error resilience, data hiding is applied to the transmission of parity bits to protect motion vectors. To do error concealment quickly, a set of edge features extracted from a block is embedded imperceptibly using data hiding into the host media and transmitted to decoder. If some part of the media data is damaged during transmission, the embedded features are used for concealment of lost data at decoder. This method decreases a complexity of error concealment by reducing the estimation process of lost data from neighbor blocks. The proposed data hiding method of parity bits and block features is not influence much to the complexity of standard encoder. Experimental results show that proposed method conceals properly and effectively burst errors occurred on transmission channel like Internet.

• Review of KIISC
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• v.22 no.8
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• pp.21-25
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• 2012

최근 해킹 및 개인정보 유출로 인한 관공서 개인정보 취급에 대한 사회적 불신감 팽배, 신뢰도 저하 문제가 발생하고 있다. 개인정보보호법, 정보통신망법의 강화에도 불구하고, 업무에 활용된 명부 등이 저장된 위치를 기억하지 못하여 그대로 방치되고 있으며, 자료공유시스템 등 웹사이트를 통해 열람(접근)된 개인정보파일이 개인 PC내 임시파일로 PC의 하드디스크에 저장되어 있다. 개인정보보호법은 2011년 3월 29일 공포되었고, 9월 30일부터 전면 실시되었다. 본 논문에서는 PC의 개인정보를 검색하고 검색된 파일을 암호화, 파일숨김을 하여 파일을 안전하게 보관하게 하며, 사용기간이 지난 파일의 경우 완전삭제를 하여 PC에서 개인정보보호법에 대응 방안을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.886-888
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• 2004

기존의 한글-안자 변환에서는 문맥정보와 통계정보를 고려하지 않는 사전기반의 단어단위 변환 방법을 사용한 반면, 본 논문에서는 언어모델 밀 변환모델을 이용한 문장단위의 한자 자동변환 방법을 제안하고. 사전 미등록어와 복합어의 한글-한자 변환을 위하여 단어분할을 변환의 숨김 과정으로 처리하는 통합모델을 사용하였다. 실험 결과, 전문용어의 한글-한자 변환에서 제한된 한자 데이터를 이용하여 기존의 사전기반 변환보다 나은 결과를 얻을 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.301-308
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• 2017

With the popularization of smart phones and the development of the Internet, many people use smart phones to conduct identity verification procedures. smart phones are easier and faster to authenticate than personal desktop computers. However, as Internet hacking technology and malicious code distribution technology rapidly evolve and attack types become more diverse, authentication methods suitable for mobile environment are required. As authentication methods, there are methods such as possessive-based authentication, knowledge-based authentication, biometric-based authentication, pattern-based authentication, and multi-element authentication. In this paper, we propose a user authentication mechanism that uses collected information as authentication factor using smart phone. Using the proposed authentication mechanism, it is possible to use the smart phone information and environment information of the user as a hidden authentication factor, so that the authentication process can be performed without being exposed to others. We implemented the user authentication system using the proposed authentication mechanism and evaluated the effectiveness based on applicability, convenience, and security.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.973-976
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• 2012

IT기기의 발전으로 다량의 개인정보들이 생성되고 이동하고 사라진다. 이에 따라 개인정보 보호의 중요성이 커지며 기존의 단순한 파일 숨김 또는 파일 잠금 형태의 보호 시스템이 아닌 데이터를 암호화하여 보안성을 높이는 시스템이 필요하다. 우리가 개발한 시스템은 윈도우즈에서는 물론 안드로이드 기기에서도 사용할 수 있으며, 윈도우즈 PC와 안드로이드 스마트폰이 통신하며 암 복호화를 가능하게 하여 활용성을 높이려 노력하였고, PC버전의 경우 대용량데이터 암 복호화 및 파일 안전 삭제 기능을 추가 하여 구현 하여 PC의 특수성도 별도로 고려하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1264-1267
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• 2012

IT기기의 발전으로 다량의 개인정보들이 생성되고 이동하고 사라진다. 이에 따라 개인정보 보호의 중요성이 커지며 기존의 단순한 파일 숨김 또는 파일 잠금 형태의 보호 시스템이 아닌 데이터를 암호화하여 보안성을 높이는 시스템이 필요하다. 우리가 개발한 시스템은 윈도우즈에서는 물론 안드로이드 기기에서도 사용할 수 있으며, 윈도우즈 PC와 안드로이드 스마트폰이 통신하며 암 복호화를 가능하게 하여 활용성을 높이려 노력하였고, PC버전의 경우 대용량데이터 암 복호화 및 파일 안전 삭제 기능을 추가 하여 구현 하여 PC의 특수성도 별도로 고려하였다.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.472-476
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• 2008

In this paper, we propose a simple and user friendly visual secret sharing scheme based on binary image. The proposed scheme is a new information hiding method which uses only bit-wise exclusive-or (XOR) operation and NOT operation to share a secret binary image information in the user friendly binary images. The proposed scheme has the following merits: (1) It provides efficient embedding and reconstruction algorithms. (2) It provides lossless and perfect reconstruction of the secret binary image. (3) It provides the detection method of its own group by sharing the user friendly image. (4) It can share same sized secret image such as original cover image unlike previous methods.