• Proceedings of the Korean Society of Computer Information Conference
• /
• 2015.07a
• /
• pp.77-78
• /
• 2015

본 논문에서는 S/W 개발 보안 지침의 사례로서 SQL 삽입에 대하여 설명한다. SQL 삽입은 입력 데이터 검증 및 표현에서 S/W 취약점 유형의 하나이다. 본 논문에서는 SQL 삽입에서 취약점 설명, 취약점 개념도, 보안 대책, 그리고 코드 예제까지 설명하도록 한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.04a
• /
• pp.850-852
• /
• 2001

Fragile 워터마킹은 이미지의 무결성을 보장하기 위하여 원본 이미지에 사람이 지각할 수 없는 데이터를 삽입하는 것을 말한다. 본 논문은 이진 데이터의 삽입이 가능하며, 원본 이미지와 삽입된 데이터의 무결성이 보장되는 fragile 워터마킹의 한 방법을 제시한다. 제시된 방법은 hash 함수와 PRBG(pseudo random bit generator)를 이용한 one-time pad를 사용하며, 한 pixel당 약 2.8125bits의 정보를 저장할 수 있다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.04a
• /
• pp.446-448
• /
• 2003

본 논문은 MPEG 비디오를 위한 양자화된 차분 에너지 워터마킹(QDEW) 알고리즘을 제안한다. 이 알고리즘은 블록의 고주파 성분인 DCT 계수를 선택적으로 제거함으로써 워터마크를 삽입하는 방식이다. 특히 제안된 방벌은 기존의 차분 에너지 워터마킹(DEW)의 단순비교방식과 다르게 양자화단위로 에너지 크기를 비교함으로써 큰 범위의 에너지가 차이날 때 발생되는 다량의 주파수제거 문제를 해결하여 화질의 열화를 방지하고 삽입되는 워터마크의 중량을 증가시켰다. 그리고 DCT계수를 제거하는 것으로만 워터마크를 삽입할 수 있기 때문에 재인코딩 과정없이 MPEG스트림에서 직접 워터마크를 삽입할 수 입는 장점이 있다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.05b
• /
• pp.362-365
• /
• 2003

본 논문은 DCT기반에서 AC 및 DC 성분에 워터마크를 삽입하는 워터마킹 방법을 제안하였다. DCT는 원영상을 8×8 블록으로 나누어서 행하였으며, 삽입한 워터마크 데이터는 평균 0, 분산 1, 길이가 1000인 정규분포 랜덤시퀀스를 사용하였다. 이 워터마크 데이터의 크기에 따라 DCT의 DC 및 AC 성분에 삽입한다. 제안한 워터마킹 알고리듬의 성능을 확인하기 위해서 컴퓨터 시뮬레이션을 수행한 결과, 제안 방법이 기존의 워터마크 방법보다 비가시성 및 견고성 면에서 우수함을 확인하였다

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.10c
• /
• pp.535-537
• /
• 2002

본 논문에서는 HVS을 이용하여 웨이브렛기반 이미지 워터마킹 기법을 제안한다. 웨이브렛 변환 된 각 밴드 중 최고 저주파 밴드에 인접한 3개의 밴드를 선택하여 각 밴드에 워터마크를 반복적으로 삽입하여 견고성을 높였다. 또한 밴드 안의 모든 계수 값에 워터마크를 삽입하지 않고 선택적으로 삽입함으로써 비가시성을 고려하였다. 저주파 영역에 워터마크를 삽입함으로서 가우시안 노이즈나 JPEG, 잘라내기 등 여러 공격모델에 대해 견고성을 잘 보여주고 있다.

• The Korean Journal of Nuclear Medicine
• /
• v.27 no.2
• /
• pp.256-260
• /
• 1993

Thirteen patients received a coralline hydroxyapatite sphere as a buried integrated ocular implant after enucleation surgery. The implant was modified by multiple drillings, 1 mm in diameter, to the center of the sphere to allow more rapid host tissue ingrowth. $^{99m}Tc$-MDP planar and tomographic bone scintigraphies were performed at various intervals after implantation (from 100 to 742 days after operation) to assess vascularization of the implant. All patients showed hot uptakes in the implants. These patients underwent a secondary drilling for the final motility peg application. The confirmation of vascular ingrowth was done by inspection of bleeding at the time of bleeding at the time of drilling from the center of the implant. Bleeding from the drilled implant was noted in all patients. In cnclusion, hot uptake in the implanted ocular hydroxyapatite implant accurately reflect vascular ingrowth into the implant.

• Composites Research
• /
• v.18 no.5
• /
• pp.1-8
• /
• 2005

Among many fabrication methods of composite materials, filament winding is the most effective method for fabricating axis-symmetric structures such as pressure tanks and pipes. Filament wound pressure tanks are under high internal pressure during the operation and it has the complexity in damage mechanisms and failure modes. For this reason, it is necessary to monitor the tank through its operation as well as whole fabrication process. A large number of sensors must be embedded into multi points of the tank from its fabrication step for monitoring the whole tank. Fiber optic sensors, especially fiber Bragg grating(FBG) sensors are widely used for various applications because of good multiplexing capabilities. However, we need to develop the embedding technique of FBG sensors into harsh inner environment of the tank far the successful embedment. In this paper, we studied the embedding technique of a number of FBG sensors into filament wound pressure tanks considering multiplexing.

• Journal of Broadcast Engineering
• /
• v.6 no.1
• /
• pp.50-57
• /
• 2001

A digital watermarking is a newly developed scheme to embed invisible or inaudible information Into the host data in order to insist the copyright of the owner or the creator. This paper describes a robust data embedding scheme that employs inner product and adaptive quantization. Compared to the previous works for digital watermarking, our proposed scheme can embed relatively large amount of Information, since a secrete key Is not directly relaxed to the watermark data. A secret key is used for the design of random direction vectors. which are taken Inner product with the DCT transformed feature set data. In odder to achieve robustness against malicious attacks. we exploit the Properties of human visual system In designing the random direction vectors which behave as embedded noises. Experimental results show that we can recover the embedded information without utilizing the original host data. We also demonstrate that the ownership assertion is possible even though The watermarked data may undergo common signal processing operations, such as JPEG compression. clopping. and filtering.

• Journal of IKEEE
• /
• v.10 no.1 s.18
• /
• pp.87-95
• /
• 2006

This paper presents the analyses of the effect of inserting border lines between different color regions on edge detection in color codes, and is not intended to present any new algorithm for color-code recognition. With its role to complement the RFID (radio frequency identification) and the wide and fast spread of digital cameras, an interest on color codes is fast increasing. However, the severe distortion of colors in obtained images prohibits color codes from expanding their applications. To reduce the effect of color distortion it is desirable to process the whole pixels in each color region statistically, instead of relying on some pixels sampled from the region. This requires segmentation, and the segmentation usually requires edge detection. To help detect edges not disconnected, we inserted border lines of the width of two pixels between adjacent color regions. Two colors were used for the border lines: one consisting of white pixels, and the other black pixels. The edge detection was performed on images with either of the two kinds of border lines inserted, and the results were compared to results without inserted border lines. We found that inserting black border lines degraded edge detection by causing zipper effect while inserting white border lines improved it compared to the cases without inserted border lines.

• Composites Research
• /
• v.25 no.4
• /
• pp.117-125
• /
• 2012

Warpage of the film insert molded (FIM) part is caused by an asymmetric residual stress distribution. Asymmetric residual stress and temperature distribution is generated by the retarded heat transfer in the perpendicular direction to the attached film surface. Since warpage was not prevented by controlling injection molding conditions, glass fiber (GF) filled composites were employed as substrates for film insert molding to minimize the warpage. Distribution of short GFs was evaluated by using micro-CT equipment. Proper models for micro mechanics, anisotropic thermal expansion coefficients, and closure approximation should be selected in order to calculate fiber orientation tensor and warpage of the FIM part with the composite substrate. After six kinds of micro mechanics models, three models of the thermal expansion coefficient and five models of the closure approximation had been considered, the Mori-Tanaka model, the Rosen and Hashin model, and the third orthotropic closure approximation were selected in this study. The numerically predicted results on fiber orientation tensor and warpage were in good agreement with experimental results and effects of GF reinforcement on warpage of the FIM composite specimen were identified by the numerical results.