• 대한의용생체공학회:의공학회지
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• 제36권5호
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• pp.169-176
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• 2015

Implantable closed-loop epilepsy controllers require ideally both accurate epileptic seizure detection and low power consumption. On-chip oscillators can be used in implantable devices because they consume less power than other oscillators such as crystal oscillators. In this study, we investigated the tolerable error range of a lower power on-chip oscillator without losing the accuracy of seizure detection. We used 24 ictal and 14 interictal intracranial electroencephalographic segments recorded from epilepsy surgery patients. The performance variations with respect to oscillator frequency errors were estimated in terms of specificity, modified sensitivity, and detection timing difference of seizure onset using Generic Osorio Frei Algorithm. The frequency errors of on-chip oscillators were set at ${\pm}10%$ as the worst case. Our results showed that an oscillator error of ${\pm}10%$ affected both specificity and modified sensitivity by less than 3%. In addition, seizure onsets were detected with errors earlier or later than without errors and the average detection timing difference varied within less than 0.5 s range. The results suggest that on-chip oscillators could be useful for low-power implantable devices without error compensation circuitry requiring significant additional power. These findings could help the design of closed-loop systems with a seizure detector and automated stimulators for intractable epilepsy patients.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.747-750
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• 2004

The researching content of this article is to implement the image grabber system for use the dental hospital image examination. It receives the NTSC analog image through CCD optical camera, which is using the close photographing. we made the image grabber board, which gathers and obtains the analog image, by PCI format. We developed the C++ application and device drive to operate this board so that we totally could implement and confirm this Image grabber system.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 추계학술대회
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• pp.29-33
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• 1992

We examine the compression performance of two irreversible (lossy) compression techniques, ADCT-VQ (Adaptive Discrete Cosine Trandform - Vector Quantization) and JPEG (Joint Photographic Experts group) which are basis of medical image information systems. Under the same compression ratio, MSE(Mean Square Error) is 0.578 lower in JPEG than in ADCT-VQ while SNR(Signal to Noise Ratio) is 1.236 dB higher in JPEG than in ADCT-VQ.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.9-12
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• 1991

The correlation search method yields velocity information by tracking scatter patterns between medical image frames. The displacement vector between a target region and the best correlated search region indicates the magnitude and direction of the inter-frame motion of that particular region. However, if the noise sources in the target region and the search region are correlated Gaussian, then the cross-correlation technique fails to work well because it estimates the cross-correlation of both signals and noises. In this paper we develop a new correlation search method which seeks the best correlated third-order statistics between a target and the search region to suppress the effect of correlated Gaussian noise sources. Our new method yields better estimations of velocity than the conventional cross-correlation method.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.293-296
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• 1996

In this paper, we studied two image characteristics, similarity and smoothness, which give rise to local and global redundancy in image representation. The similarty means that any patterns in the image repeat itself anywhere in the rest of image. The smoothness means that the gray level values within a given block vary gradually rather than abruptly. In this sense, we propose a lossless medical image compression scheme which exploits both types of redundancy. This method segments the image into variable size blocks and encodes them depending on characteristics of the block. The proposed compression schemes works better than other compression schemes such as the huffman, the arithmetic, the Lempel-Ziv and the lossless scheme of JPEG.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 춘계학술발표대회
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• pp.1250-1252
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• 2009

Cellular 망에서의 무선통신은 일반적으로 하나의 송수신안테나를 사용하거나 둘 이상의 송수신 안테나를 사용한다. MRRC(Maximum Ratio Receiver Combining)기법의 경우 여러 안테나를 사용하여 신호룰 수신하는 시스템이며, 이 경우 각 안테나의 채널에 따른 이득과 손실을 고려한 수신기가 제안되었다. Cellular model에서의 SINR 값에 따른 추정을 통해 최적 결합 기법을 적용한 MRRC 수신기를 사용하는 경우, 이에 따른 Cellular modeling을 이용하여 시스템 레벨에서의 MRRC 기법과 Optimum-MRRC 기법을 도입으로 인한 성능의 개선을 알 수 있다.

• 전자공학회논문지CI
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• 제44권3호
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• pp.43-48
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• 2007

초고속 인터넷의 발달과 휴대용 임베디드시스템이 보편화된 유비쿼터스 환경 아래에서 의료영상처리 분야에도 언제 어디서든지 원하는 환자에 대한 정보를 검색하고 판독할 수 있는 시스템에 대한 연구 및 개발이 활발하게 이루어지고 있다. 특히, scout 영상은 진단 목적 이외에 새로운 응용분야에서 필요로 하고 있다. 유비쿼터스 시스템 개발로 의료 영상 뷰어는 PACS 시스템 및 웹브라우저와 결합한 병원에서 활용되고 있다. 본 논문은 무선 환경에서 잠재력을 보여주고 있는 이동단말기 기반의 의료영상 뷰잉시스템을 구현하였다.

• 정보보호학회논문지
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• 제20권6호
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• pp.251-260
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• 2010

의료서비스와 IT 기술간의 융합으로 환자 개인의 건강정보가 전자의무기록(EHR)의 보급과 함께 빠르게 전자화되고 있다. 이와 함께 유헬스사회에 접어들면서 전자화 된 환자의 건강기록들을 진료 이외의 공중보건 및 의학 분야의 연구, 의료서비스 향상을 위해 사용하고자 하는 2차이용의 요구가 증가하고 있다. 개인건강정보의 2차이용으로 의학 분야의 발전의 매우 유익한 일이지만 부주의하게 개인의 건강정보를 이용하는 경우 환자 개인의 프라이버시 손상이 발생, 더불어 2차이용융 통한 연구나 서비스 발전에도 제한이 발생할 수 있다. 하지만 아직 개인건강정보를 이용한 2차적 이용에 대해 체계적인 연구나 논의가 없는 것이 현실이다. 따라서 본 논문에서는 개인건강정보의 2차이용과 관련하여 국내외의 법안들을 살펴보고 이를 비교 분석하여 앞으로 개인의 프라이버시를 존중하고 더불어 의료분야 서비스 있는 방향을 제시하고자 한다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.294-298
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• 1997

In the magnetic resonance imaging, the fast spin echo imaging technique is a widely used clinical imaging method, since its scanning time is much shorter than the conventional spin echo imaging and it gives the almost same image quality. However, the fast spin echo technique has two times longer imaging time or the dual echo acquisition which can obtain a spin density image and a $T_2$-weighted image simultaneously. To overcome such a drawback, this paper proposes a new fast dual echo imaging technique which can give the same quality images at the single echo imaging time. The proposed technique reduces the imaging time by overlapping most of echo train data for each image reconstruction. In order to verify its validity and usability the human head experimental results which were obtained at the 0.3T permanent MRI system are presented.

• 전자통신동향분석
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• 제32권6호
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• pp.27-39
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• 2017

A variety of medical devices are utilized to repair or help injured body functions after accidental injury(such as a traffic accident), population aging, or disease. Such medical devices are being actively researched and developed in portable form, skin patchable type, and further, implantable form. In the future, active implantable medical devices for neuro and brain sciences are expected to be developed. Active implantable medical devices that detect brain signals and control neurology for a wider understanding of human cognition and nerve functions, and for an understanding and treatment of various diseases, are being actively pursued for future use. In this paper, the core elements of implantable devices that can be applied to neuro and brain sciences are classified into electrode technologies for bio-signal acquisition and stimulation, analog/digital circuit technologies for signal processing, human body communication technologies, wireless power transmission technologies for continuous device use, and device integration technologies to integrate them. In each chapter, the latest technology development trends for each detailed technology field are reviewed.