• The KIPS Transactions:PartC
• /
• v.8C no.5
• /
• pp.499-506
• /
• 2001

In this work, we present an iris pattern recognition method as a biometrically based technology for personal identification and authentication For this, we propose a new algorithm for extracting an unique feature from the iris of the human eye and representing this feature using the discrete Walsh-Hadamard transform. From the computational simplicity of the adopted transform, this can perform the personal identification and authentication in a fast manner to accomplish the information security.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.47 no.1
• /
• pp.9-16
• /
• 2020

The aim of this study is to investigate visual exploration of children and adolescents during dental treatment by examining time ratio of eye opening in various age groups. This study reviewed 5 - 15 year-old patients who visited the department of pediatric dentistry of Yonsei University Dental Hospital from March to October 2018. Restorative treatment or sealant application was done by one pediatric dentist. A trained observer used 2 stopwatches to measure total treatment time and time of open eye. Average ratios of eye opening were calculated and compared. 60 patients were investigated, with 15 patients in each age group. Average ratio of eye opening increased as age decreased (p < .001). The average of 13 - 15 year-olds was significantly shorter than that of children younger than 12 years (p < .005). This study indicated that children have higher rates of eye opening during dental treatment than adolescents.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.6
• /
• pp.1296-1301
• /
• 2006

The human eye is exposed to UV and visible light. UV light exposure becomes harmful to the eye. Protection for eyes should block all ultraviolet rays. In our study, organic-inorganic hybrid materials have been applied to UV blocking coatings with UV absorbing materials on transparent plastics. The optical properties of UV blocking coatings were investigated in PMMA, CR 39 and PC substrates. In case of all UV absorbers, the transmission of UV light decreases with an increased amount of absorber. Our findings indicate that PMMA significantly reduced the transmission of UV radiation, CR 39 showed moderate decrease, while UV-uncoated PC had some UV blocking properties. Adhesion, hot water resistance and chemical resistance of the UV-coated CR 39 lenses were good. Pencil hardness were 4H. Abrasion resistance were poor.

• Journal of Biomedical Engineering Research
• /
• v.20 no.4
• /
• pp.401-407
• /
• 1999

A microsurgery telerobotic system has been developed to aid surgeons from physiological tremor, eye stram, hand tremor, contagious and radioactive hazard. This paper identifies four general areas of advanced microsurgery and analyzes the motion, tools, accuracy and applying forces with respect to microsurgery tasks, and proposes the criteria to design the microsurgical robot. The analysis of microsurgery can be helpful to clarify some basic concept and design of surgical robots. Based on this analysis results, we propose an efficient in-parallel-platform manipulator having a special kinematic structure suitable for microsurgery.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.1
• /
• pp.27-34
• /
• 2005

Photochromic lens is the color changing lens from colorlessness to colorness when exposed to UV light. It can protect eyes from UV-B light which cause the cataract and can be used as sunglass in the summer since it can cut off 70~80% of sun light. Surface coating technique was used to develop lens which has 70% light transmittance and of which fading time of color change is within 5 min. Various color lenses were developed so that these had various color such as blue, green, brown, violet, yellow and red etc. Lens has an excellent physical properties, 100% adhesion and 4~5H hardness. The chemical and the scratch resistance of this lens were the greatest and the thermal stability was also higher. The clinical trial of developed lens were applied to 65 patients who had photophobia by various reasons at ophthalmology of Soonchunhyang University Hospital. Results showed that glaring was significantly reduced and the visual health were remarkably improved. Especially, anti-glaring effect in the night was great for the patient who had the LASIK operation. Protection of UV-B and blue light also can prevent the patient from cataract and the yellowish crystalline lens at old ages. Through the result of clinical. trial, we know that photochromic lens could be a new technique for both cure and precaution of photophobia.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.6
• /
• pp.937-942
• /
• 2002

The use of digital imaging technique and digital contents based on internet has grown rapidly for last several years, and the needs of digital image protection become more important. For the purpose of copyright protection on digital image, the verification of authentication techniques like content authentication, ownership authentication, illegal copy and etc are needed. Digital watermarking, the invisible encryption technique to insert digital watermark into image the sophisticated perceptual information should be used for providing transparency and robustness of images on watermarking process. In this paper, we implement the algorithm for preventing forged attack, ownership protection and authentication by transforming the wavelet algorithms in frequency domain in terms of human visual system.

• Landscaping Tree
• /
• s.143
• /
• pp.40-41
• /
• 2014

회화나무는 내한성(耐寒性), 내공해성이 강하여 도심지의 공원수, 가로수로 많이 심고 있으며 수형이 아름다워 정원수로도 활용되고 있다. 또한 옛날부터 회화나무를 집에 심으면 가문에 큰 인물이나 큰 학자가 나온다고 하여 고결한 선비의 집이나 서원, 사찰, 대궐 같은 곳에 주로 심어져 천연기념물이나 보호수로 여러 지역에 남아 있다. 최근에 가로수나 조경수로 심어진 회화나무의 줄기나 가지에 혹이 있는 나무들이 쉽게 눈에 띄는데 "회화나무 녹병"에 감염된 징표이다. 회화나무에서 가장 문제가 되고 있어 이 병을 소개한다.

• 정보화사회
• /
• s.24
• /
• pp.21-27
• /
• 1989

국내외적인 시장환경 변화로 국내 정보통신산업은 상당한 어려움을 겪고 있다. 세계시장에서의 자국시장 보호정책강화는 수출위주의 산업구조를 갖고 있는 우리나라에 많은 영향을 주고 있다. 이러한 상황에 따라 급성장세를 지속해오던 우리의 경제성장률이 금년들어서는 눈에 띄게 둔화되고 있는 것이다. 특히 정보산업계에서는 통신시장 개방에 따른 대응책과 자구책 마련에 총력을 기울이고 있다. 한.미 양국간에 대표자회담이 연속적으로 열리고 있으며 이를 보는 국민들의 관심도 고조되고 있다. 협회는 이러한 환경변화에 능동적으로 대처하고, 새로운 방향을 모색키 위한 일환으로 이우재 체신부 장관을 초청, 협회 회원사 대표들과의 상견인사와 의견교환의 자리를 만들었다. 본고에서는 이번 행사의 주요 내용을 요약, 정리한다.

• JOURNAL OF ELECTRICAL WORLD
• /
• no.6 s.138
• /
• pp.89-92
• /
• 1988

변압기 1차측에는 과부화 보호를 위한 고압 컷 아웃이 사용되고 여기에 텐션형 퓨즈가 장착되어 있다. 고압 컷 아웃은 전류개폐능력 관계로 300kVA 이하인 변압기에 사용된다. 변압기 운전중은 고압 컷 아웃의 내부점검을 할 수 없기 때문에 통상은 눈으로 외시점검을 하는 것이 일반적이다. 고압 컷 아웃의 사고로는 퓨즈 용단, 애자부의 균열, 오손 등으로 인한 지락이나 접촉 칼날부의 접촉 불량, 본체의 파손 등이 있다. 이러한 사고를 사전에 발견하기는 곤란한 경우가 많은 것 같다. 이러한 사고를 사전에 발견하기는 곤란한 경우가 많은 것 같다. 다음은 고압 컷 아웃이 파손해서 정전된 사례이다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2001.11a
• /
• pp.708-712
• /
• 2001

디지털 데이터의 저작권 보호를 위하여 최근 디지털 워터마킹에 관하여 많은 연구가 이루어지고 있다. 디지털 워터마킹이란 인간의 시각이나 청각이 인지할 수 없는 범위 내에서 디지털 데이터의 값을 약간 변경함에 따라 워터마크라고 하는 저작권 정보를 몰래 삽입하는 방법이다. 본 논문에서는 비 압축 비디오 계열(uncompressed video sequence)에 디지털 워터마크를 삽입하기 위한 방법을 보여준다. 대역 확산 기법을 이용하여 비디오에 pseudo-noise signal을 눈에 보이지 않도록 추가하고, 여러 조작에 대해 강하도록 구성하였다. 성능을 평가하기 위하여 비디오에 워터마크를 삽입하고 그 유효성을 보인다.