• Journal of Chest Surgery
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• 제3권2호
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• pp.127-132
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• 1970

A patient was 29 year old house wife who was admitted to the Yonsei University Medical Center on 6 th of Nov., in 1970, with chief complaints of complete loss of bilateral visual acuity, generalized weakness, frequent palpitations, claudication of masseter muscles and intermittent fainting. These symptoms were developed 5 years prior to admission. Physical finding on admission revealed complete loss of bilateral visual acuity, absence of both radial and carotid pulse, but there was good femoral and popliteal pulse. She couldn't open her mouth as she desired and had weakness of mastication. Radiological findings of plane chest PA were not significant. Aortogram(Cineangiogram) showed non-visualization of both carotid and subclavian arteries. It showed only innominate and interal mammary artery preoperatively. The operative findings were as follows: There were complete obliterative changes in both common carotid and subclavian arteries, and periarteritis in the innominate artery. Tube Dacron Prosthesis Bypass with V-arm between innominate artery and both common carotid arteries was performed after thromboendarterectomy. Histopathological finding of the thromboend arterectomy specimen was compatible with pulseless disease, which showed marked fibrous thickening of intima and a diffuse inflammatory cell infiltration of the whole layers. Her postopererative course was uneventful. Follow up aortogram(Cineangiogram) was taken on 11th postoperative day, which revealed both common carotid arteries patent. Her preoperative Subjective symtoms disappeared remarkably, such as her visual acuity improved much, fainting and vertigo disappeared completely and she can go to bath room without difficulty and help. Another patient was 34 year old house wife who was admitted on August, 1964 with chief complaints of frequent fainting and progresive visual loss. She was operated only thromboendarterectomy of both common carotid arteries. Postoperative course was smooth and subjective symptoms were disappeared.

• 대한기계학회논문집A
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• 제27권12호
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• pp.2079-2084
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• 2003

In biological cell manipulation, manual thrust or penetration of an injection pipette into an embryo cell is currently performed by a skilled operator, relying on visual feedback information only. Accurately measuring cellular forces is a requirement for minimally invasive cell injections. Moreover, the cellular force sensing is essential in investigating the biophysical properties for cell injury and membrane modeling studies. This paper presents cellular force measurements for the force feedback-based biomanipulation. Cellular force measurement system using piezoelectric polymer sensor is implemented to measure the penetration force of a zebrafish egg cell. First, measurement system setup and calibration are described. Second, the force feedback-based biomanipulation is experimentally carried out. Experimental results show that it successfully supplies real-time cellular force feedback to the operator at tens of uN and thus plays a main role in improving the reliability of biological cell injection tasks.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 추계학술발표대회
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• pp.1118-1121
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• 2010

With the advent of cell phone digital cameras, and sophisticated photo editing software, digital images can be easily manipulated and altered. Although good forgeries may leave no visual clues of having been tampered with, they may, nevertheless, alter the underlying statistics of an image. Most digital camera equipped in cell phones employ a single image sensor in conjunction with a color filter array (CFA), and then interpolates the missing color samples to obtain a three channel color image. This interpolation introduces specific correlations which are likely to be destroyed when tampering with an image. We quantify the specific correlations introduced by CFA interpolation, and describe how these correlations, or lack thereof, can be automatically detected in any portion of an image. We show the efficacy of this approach in revealing traces of digital tampering in lossless and lossy compressed color images interpolated with several different CFA algorithms in test cell phones.

• 조형예술학연구
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• 제3권
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• pp.62-86
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• 2001

This study is based on theoretical background about movements of visual communication highlighted in digital age. Such movements are variously expressed in animation with the advancement of media, and their expression has great effect on visual art. Artists' concern and endeavor about movement expression techniques have been continued by impressionism, expressionism, futurism, cubism closely related with the birth of movie from late 19th century to early 20th century. At that time, stationary 2D space in plane screen couldn't express movement or time directly. Later, artists and designers have attempted to approach illusions in pictures or 4 dimension and movements by 2D or 3D computer graphics. The visual image in present digital age is to see, to hear, to feel by timing, so it is necessary for the most efficient way of message communication. And then, it is the time to start new, scientific, and creative study about production techniques of animation and expression of movements, since domestic animation productions are rapidly changed from cell to digital. The aim of this study is to clarify the motive of movement by theoretical inquiry of animation. Various aspects of animation as synthetic art have been examined by mathematical, scientific, and philosophical viewpoint. The results will be useful to the expression of motions for maximization of emotional effect in animation production or basic data of virtual simulation about certain situation. Therefore, such study should be managed as multidisciplinary research in the rapidly changing visual culture paradigm. namely, animation includes much more imaginative & creative power than simple function or techniques, so it has to be recognized as special synthetic art(visual art) constructing an area, the formative art with philosophical viewpoint and scientific principles.

• 한국지리정보학회지
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• 제6권2호
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• pp.65-79
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• 2003

본 연구에서는 지리정보시스템(GIS)을 사용하여 Visual MODFLOW 지하수 유동 모델링 툴에 필요한 입력 인자(자료)를 과학적으로 만들어줄 뿐만 아니라, 모델링을 위해 입력된 인자들과 모델링 후 생성된 결과물들을 DB화하고 이를 체계적으로 관리할 수 있도록 하는 Visual MODFLOW 지하수 유동 모델링을 위한 GIS 기반 전 후처리기를 개발하였다. 이 전 후처리기의 모듈로서 가장 특징적인 것은 모델구역 내에서 관정 주변에 상대적으로 조밀하게 즉, 셀의 크기가 다양한 그리드를 GIS ArcView에서 자동 또는 반자동으로 형성하는 툴을 개발하였다는 것이다. 모델링 구역 내에서 다양한 경계조건(boundary condition)을 반영한 DXF 생성을 위한 툴 개발도 들 수 있다. 아울러 2차원인 ArcView를 이용하여 3차원 수리지질구조를 생성하고, MODFLOW 프로그램의 입출력 자료형태와 동일한 위상구조를 유지한 채 전 후처리하도록 한 것은 이 연구의 가장 큰 성과이다.

• 한국정보통신학회논문지
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• 제11권11호
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• pp.2143-2149
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• 2007

최근 시각 장애인을 위한 인공망막 모델 구현에 관한 연구 중 시피질 자극기 기술은 시각 자극 전달의 중간 단계를 생략하고 직접 뇌세포를 자극하는 것이다. 본 논문에서는 망막에서 시각 피질로 시각정보를 전달할 때 발생하는 시각 피질의 특성, 즉 방향성에 대한 반응 특성을 특징 데이터로 구성하여 인식함으로써 인간 시각 정보 처리와 유사한 영상 추출 및 인식 모델을 제안한다. 제안된 방법은 영상의 특징을 추출 한 후 Delta-bar-delta 기반 오류 역전파 알고리즘을 적용하여 영상의 특징들을 인식한다. 제시된 방법의 성능을 분석하기 위하여 다양한 숫자 패턴들을 대상으로 실험한 결과, 제안된 망막 세포로부터 전달된 정보를 방향성에 대한 민감성을 고려하여 영상의 특성을 추출하여 인식하는 모델이 기존의 영상 추출 및 인식 모델보다 인식률에 있어서는 별 차이가 없지만 다양한 실험에서 확인할 수 있듯이 인간 시각과 같이 인식 성능이 민감하지 않는 것을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.237-240
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• 2003

In biological cell manipulation, manual thrust or penetration of an injection pipette into an embryo cell is currently performed by a skilled operator, relying on visual feedback information only. Accurately measuring cellular forces is a requirement for minimally invasive cell injections. Moreover, the cellular farce sensing is essential in investigating the biophysical properties for cell injury and membrane modeling studies. This paper presents cellular force measurements for the force feedback-based biomanipulation. Cellular force measurement system using piezoelectric polymer sensor is implemented to measure the penetration force of a zebrafish egg cell. First, measurement system setup and calibration are described. Second, the force feedback-based biomanipulation is experimentally carried out. Experimental results show that it successfully supplies real-time cellular force feedback to the operator at several tens of uN and thus plays a main role in improving the reliability of biological cell injection tasks.

• 콘크리트학회논문집
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• 제17권5호
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• pp.829-834
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• 2005

A series of reinforced G109 type specimens was fabricated and pended with a 15 weight percent NaCl solution. Mix design variables included 1) two cement alkalinities (equivalent alkalinities of 0.32 and 1.08), 2) w/c 0.50 and 3) two rebar surface conditions (as-received and wire-brushed). Potential and macro-cell current between top and bottom bars were monitored to determine corrosion initiation time. Once corrosion was initiated, the specimen was ultimately autopsied to perform visual inspection, and the procedure included determination of the number and size of air voids along the top half of the upper steel surface. This size determination was based upon a diameter measurement assuming the air voids to be half spheres or ellipse. The followings were reached based upon the visual inspection of G109 specimens that were autopsied to date. First, voids at the steel-concrete interface facilitated passive film breakdown and onset of localized corrosion. Based upon this, the initiation mechanism probably involved a concentration cell with contiguous concrete coated and bare steel serving as cathodes and anodes, respectively. Second, the corrosion tended to initiate at relatively large voids. Third, specimens with wire-brushed steel had a lower number of voids at the interface for both cement alkalinities, suggesting that air voids preferentially formed on the rough as-received surface compared to the smooth wire brushed one.

• The Korean Journal of Physiology and Pharmacology
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• 제12권6호
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• pp.307-314
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• 2008

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Among the many issues for prosthesis development, stimulation encoding strategy is one of the most essential electrophysiological issues. The more we understand the retinal circuitry how it encodes and processes visual information, the greater it could help decide stimulation encoding strategy for retinal prosthesis. Therefore, we examined how retinal ganglion cells (RGCs) in in-vitro retinal preparation act together to encode a visual scene with multielectrode array (MEA). Simultaneous recording of many RGCs with MEA showed that nearby neurons often fired synchronously, with spike delays mostly within 1 ms range. This synchronized firing - narrow correlation - was blocked by gap junction blocker, heptanol, but not by glutamatergic synapse blocker, kynurenic acid. By tracking down all the RGC pairs which showed narrow correlation, we could harvest 40 functional connectivity maps of RGCs which showed the cell cluster firing together. We suggest that finding functional connectivity map would be useful in stimulation encoding strategy for the retinal prosthesis since stimulating the cluster of RGCs would be more efficient than separately stimulating each individual RGC.

• 한국통신학회논문지
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• 제38C권9호
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• pp.781-786
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• 2013

Multiplexing information over parallel data channels based on RF MIMO concept is possible to achieve considerable data rates over large transmission ranges with just a single transmitting element. Visual multiplexing MIMO techniques will send independent streams of bits using the multiple elements of the light transmitter array and recording over a group of camera pixels can further enhance the data rates. The proposed system is a combination of the reliance on computer vision algorithms for tracking and OOK cell frame modulation. LED array are controlled to transmit message in the form of digital information using ON-OFF signaling with ON-OFF pulses (ON = bit 1, OFF = bit 0). A camera captures image frames of the array which are then individually processed and sequentially decoded to retrieve data. To demodulated data transmission, a motion tracking algorithm is implemented in OpenCV (Open source Computer Vision library) to classify the transmission pattern. One of the most advantages of proposed architecture is Computer Vision (CV) based image analysis techniques which can be used to spatially separate signals and remove interferences from ambient light. It will be the future challenges and opportunities for mobile communication networking research.