• 방송공학회논문지
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• 제25권1호
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• pp.58-66
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• 2020

영상 촬영 시 객체의 움직임, 탈초점(Out-of-focus) 등의 이유로 영상 흐려짐 현상이 빈번하게 발생하며, 이 과정에서 선명한 영역의 고주파 성분이 급격하게 감소하게 된다. 이러한 성질을 바탕으로, 본 논문에서는 질감 특징 표현자를 사용하여 별도의 주파수 변환 과정 없이 고주파 성분을 추정하고, 이를 바탕으로 흐려진 영역을 검출하는 방법을 제안한다. 제안하는 방법은 학습 기반 질감 표현자와 유역(Watershed) 기반 질감 표현자를 함께 이용하여 다양한 환경에서도 흐려진 영역을 검출할 수 있다. 또한, 흐려짐을 검출하는 최소 단위를 화소 단위에서 영역 단위로 확장하여 처리 속도를 향상시키고, 영상 보정 기법을 이용하여 흐려짐 검출 성능을 개선하였다. 실험 결과는 제안하는 방법이 기존의 흐려짐 검출 방법 대비 성능이 향상되었음을 보여준다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.7.2-7.2
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• 2009

Polyvalent nanoparticle-DNA conjugates exhibit a variety of unique features such as programmable assembly and disassembly, sharp melting transitons, intense optical properties, high stability, enhanced binding properties, and easy fabrication of the surface nature by chemical and physical modification. The unique properties of nanoparticle-DNA conjugates enable one to build up a number of versatile assay schemes for the detection of various targets. In addition, nanoparticle-RNA conjugates also demonstrate great promise of therapeutic applications in the context of RNA interference when combined with polymeric materials. In this presentation, representative examples of each aspect of nanoparticle-oligonucleotide conjugates will be discussed.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2116-2124
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• 2003

An experimental study providing additional knowledge of quasi-conical symmetry in swept shock wave/turbulent boundary-layer interactions is described. When a turbulent boundary layer on the flat plate is subjected to interact with a swept planar shock wave, the interaction flowfield far from fin leading edge has a nature of conical symmetry, which topological features of the interaction flow appear to emanate from a virtual conical origin. Surface streakline patterns obtained from the kerosene-lampblack tracings have been utilized to obtain representative surface features of the flow, including the location of the virtual conical origin. The scaling law for the sharp-fin interactions suggested by previous investigators has been reexamined for different freestream Mach numbers. It is noticed that the scaling law reasonably agrees with the present experimental data, however, that the law is not appropriate to estimate the location of the virtual conical origin. Further knowledge of the correlation for the virtual conical origin has thus been proposed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1080-1084
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• 2011

Urban maglev should have such characteristics as not only environmentally friendliness and excellent driving capability but also curve negotiation performance because its routes have many sharp curves. Due to normal mechanism of urban maglev its relative displacements of secondary spring are bigger than conventional railway vehicle and the centering force of levitation magnet is smaller than wheel-on-rail system. These features of maglev affect the curving negotiation and so the additional steering device is to be required on Urban maglev to improve the running performance at sharp curve of less than about R50m. Some developed urban maglev had the passive steering device which consists of mechanical linkage or hydraulic cylinder and closed-route piping. But it has drawback as complexity of layout of understructure of vehicle and functional limitation of passive mechanism regarding transient curve. These demerits could be solved by using active steering system. But it has a weak point that an active device should have actuators and additional inverter or hydraulic power source. In this paper, the semi-active steering system for urban maglev is to be introduced.

• Annals of Clinical Neurophysiology
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• 제4권2호
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• pp.137-139
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• 2002

Background : Subtle status epilepticus (SE) is an end-stage of convulsive SE. This phenomenon might be a clinical expression of neuronal exhaustion caused by sustained electrical discharges. As subtle SE may show diverse clinical features, early detection depends on clinical suspicion. Case : A 68-year-old woman was presented with repetitive involuntary movement of right limbs after two generalized tonic-clonic seizures. She experienced right middle cerebral artery infarction 4 months ago, and after the event, left side hemiplegia sustained. These seizures were first-ever after the cerebral infarction. Orientation and verbal responses were fairly preserved but general cognitive function was minimally slowed. During the video-EEG monitoring, repetitive sharp waves were noted in the right hemisphere and these sharp waves occasionally spread to the contralateral side. Her right side involuntary movement was identifiable when the epileptic discharges were found on her right hemisphere. Conclusion : We suggested that this unexpected convulsive movement is a reflection of earlier exhaustion in the right hemisphere or deefferentation of right hemisphere because of preexisting neuronal damage.

• 대한기계학회논문집B
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• 제24권11호
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• pp.1523-1534
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• 2000

The performance of a number of existing dynamic subgrid-scale(SGS) models is evaluated in large-eddy simulations(LES) of two prototype transitional and turbulent shear flows, a planar jet and a channel flow. The dynamic SGS models applied include the dynamic Smagorinsky model(DSM);Germano et al. 1991, Lully 1992), the dynamic tow-component model(DTM; Akhavan et al. 2000), the dynamic mixed model(DMM;Zang et al, 1993). and the dynamic two-parameter model(DTPM; Salvetti & Banerjee 1995). The results are compared with those for DNS for their evaluation. The LES results demonstrate the superior performance of DTM with use of a sharp cutoff filter and DMM with use of a box filter, as compared to their respect counterpart DSM, in predicting the mean statistics, spectra and large-scale structure of the flow, Such features of DTM and DMM derive from the construction of the models in which tow separate terms are included to represent the SGS interactions; a Smagorinsky edd-viscosity term to account for the non-local interactions, and a local-interaction term to account for the nonlinear dynamics between the resolved and subgrid scales in the vicinity of the LES cutoff. As well, overall the SGS models using a sharp cutoff filter are more successful than those using a box filter in capturing the statistics and structure of the flow. Finally, DTPM is found to be compatible or inferior to DMM.

• Applied Microscopy
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• 제43권2호
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• pp.47-53
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• 2013

The trichomes on leaves of three species of Mentha such as M. spicata, M. suaveolens, and M. piperita var were examined by scanning electron microscopy. Simple non-glandular trichomes and peltate glandular trichomes were distinctively occurred on these leaves. In M. spicata, short and sharp non-glandular trichomes were dominantly appeared on adaxial surface, whereas capitate glandular trichomes were commonly localized on abaxial surface. In M. suaveolens, non-glandular trichomes were identified with simple unbranched and branched. Unbranched trichomes which were sharp and pointed in shape occurred on adaxial surface, however, branched and v-shaped trichomes appeared abundantly on abaxial surface. Peltate trichomes consisted of a large eight-celled head. Small capitates trichomes consisted of a cylindrical head with an one-celled uniseriate stalk. In M. piperita var, single non-glandular trichomes and peltate trichomes were present on adaxial surface. Small capitate trichomes consisted of a globose unicellular head with a two- or three-celled uniseriate stalk. Peltate trichomes were distinctly present on abaxial surface, whereas they were not observed on adaxial surface. The trichomes were less dense in this species. Peltate trichomes consisted of a large eight-celled head, with an enlarged secretory cavity, attached to an one-celled short stalk.

• 방송공학회논문지
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• 제23권4호
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• pp.484-494
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• 2018

Cho 등의 균일 모션 블러 제거 알고리듬은 영상 내 외곽선 영역을 선명하게 복원하지 못한다는 문제점이 있다. 이러한 문제점을 극복하기 위해 본 논문에서는 한 장의 정지 영상에서 발생하는 블러 (Blur)현상을 블러된 계단형 신호를 뚜렷한 외곽선으로 복원해주는 쇼크 필터 (Shock filter)와 영상에서 특징을 추출하여 학습하는 합성곱 신경망 (Convolutional Neural Network: CNN)을 이용하여 선명한 영상을 복원하고 이 영상으로부터 균일 모션 (Uniform motion) 블러를 측정하여 영상 내 블러 현상을 제거하는 효과적인 알고리듬을 제안하고자 한다. 제안된 알고리듬은 쇼크 필터와 합성곱 신경망을 이용하여 선명한 영상을 복원함으로써 기존 알고리듬의 단점을 개선하였다. 실험 결과를 통해 제안하는 알고리듬이 기존 알고리듬에 비해 객관적 및 주관적인 평가에서 우수한 복원 성능을 나타냄을 확인하였다.

• 한국정보통신학회논문지
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• 제19권12호
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• pp.2949-2955
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• 2015

최근 들어 사진, 애니메이션, 동영상과 같은 디지털 시각 매체가 폭발적으로 증가함에 따라서 의도적 또는 비의도적으로 입력 영상 내에 모자이크 블록들을 생성해야 할 필요성이 증가하고 있다. 본 논문에서는 입력된 컬러 영상에 존재하는 모자이크 블록들을 경계 특징을 이용하여 효과적으로 검출하는 방법을 제안한다. 제안된 방법에서는 먼저 입력 영상으로부터 캐니 에지를 검출하고, 검출된 에지로부터 모자이크 블록의 경계 특징을 추출하여 모자이크 블록이 존재할 가능성이 있는 후보 영역들을 찾는다. 그런 다음, 기하학적인 특징을 활용하여 비 모자이크 영역들을 제거하고 실제적인 모자이크 블록들만을 검출한다. 본 논문의 실험 결과에서는 제안된 방법이 다양한 종류의 입력 영상에서 모자이크 블록들을 강건하게 검출한다는 것을 보여준다.

• 대한기계학회논문집A
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• 제20권6호
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• pp.1743-1752
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• 1996

In this paper, a precision inspection technique using CAD/CAI integration is proposed for the parts having very thin and sharp 3 dimensional curve features. The technique begings with feature reconstruction of turbine blades which have 3 dimensional combined feometry, such as splines, and thin circles. The alifnment procedures consistsb of two phases-rough and fine phases : rough phase alignment is based on the conventional 6 point5s probing on the clear cut surfacef, and fine phase alignment is based on the intial measurement on the 3 dimensional curved parts using an lterative measurement feed-back least sequares technique for alignment. Forf the analysis of profile tolerance of parts, the actual measured points are obtained by finding the closet points on the CAD geometry by the developed subdivision technique and the Tschebycheff norm is applied based on iterative fashion, giving accurate profile tolerance value. The developed inspection technique is applied to practical procedures of blade manufacturing and demonstrated high performance.