• 제목/요약/키워드: litter filter

검색결과 8건 처리시간 0.026초

시공간 3차원 결합 잡음제거 필터 (Spatio-Temporal 3D Joint Noise Reduction Filter)

  • 홍성훈;홍성용
    • 한국멀티미디어학회논문지
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    • 제5권2호
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    • pp.147-157
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    • 2002
  • 영상 시퀀스에 포함된 잡음은 화질을 열화시키고 중요한 영상의 미세 정보를 훼손시킨다. 또한 잡음은 영상의 복잡성을 증가시키므로 영상의 압축효율을 저하시킨다. 본 논문에서는 특성이 서로 다른 두개의 적응형 잡음제거 필터를 결합적으로 연결하여 잡음을 제거하는 공간결합필터와 시간결합필터를 제시하고, 이 결합필터들을 연결한 IIR필터 구조를 갖는 3차원 잡음제거 필터를 제시한다. 제시된 잡음제거 필터는 영상의 에지와 미세정보를 유지하면서도 평탄한 영상영역에 대해서는 강한 잡음제거를 수행하며 이웃한 프레임 사이에서도 잡음에 의한 시간적인 깜박임을 억제한다. 실험결과 제안된 잡음제거 필터는 기존 방식들에 비하여 객관적 화질뿐만 아니라 주관적인 화질을 크게 향상시킴을 알 수 있었다.

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강인성을 고려한 능동소음제어 시스템 (Robust Active Noise Control System)

  • 정찬수;오학준;구춘근;이상철;정양웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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    • pp.332-334
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    • 1994
  • This paper proposes a robust active noise control (ANC) system. The system constructs filter with a standard model. An adaptive litter, connected to the system in parallel, compensates the modeling error. When the adaptive filter does not work, the proposed system is robust while the conventional system loses the noise control capability. But proposed ANC system shows that the performance is comparable with that of the conventional ANC system under normal conditions.

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물이끼(Sphagnum palustre) 생육이 가능한 인공습지 사례보고 (A Case Report on the Constructed Wetland for the Growth of Sphagnum palustre)

  • 홍문기;김재근
    • 한국환경복원기술학회지
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    • 제16권6호
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    • pp.93-107
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    • 2013
  • Construction of an artificial wetland for the growth of Sphagnum palustre with emergent macrophytes (Phragmites australis, Typha angustifolia, and Zizania latifolia) was firstly tried and the growth of those plant components according to various environmental combinations has been monitored for three years. Above-ground dry weight of Z. latifolia ($1,500g/m^2$) was higher than T. angustifolia ($900g/m^2$) and P. australis ($500g/m^2$) under most environmental conditions. In overall, planted emergent macrophytes seemed to prefer polishing sand without moss peat as a substrate and relatively deep water-depth condition (20cm) rather than shallow water-depth (5cm). Despite of high calcium content in inflow water (> 15ppm) into the constructed wetland, S. palustre populations have survived in most experimental plots during the monitoring period. Substrate layer including moss peat with high surface-area might play a role as an ion-filter. After three years, relatively thicker litter-layer in Z. latifolia plots due to vigorous growth appeared to heavily depress S. palustre by physical compressing and complete shading processes. Most of all, for the continuous growth of S. palustre, physio-chemical characteristics of water and substrate must be carefully managed. In addition, companion emergent species should be also cautiously selected not to depress S. palustre by much litter production. We suggest P. australis and T. angustifolia as companion species rather than Z. latifolia.

Basic study on high gradient magnetic separation of nano beads using superconducting magnet for antibody purification

  • Jeongtae Kim;Insung Park;Gwantae Kim;Myunghwan Sohn;Sanghoon Lee;Arim Byun;Jin-sil Choi;Taekyu Kim;Hongsoo Ha
    • 한국초전도ㆍ저온공학회논문지
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    • 제25권4호
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    • pp.60-64
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    • 2023
  • The manufacturing process of antibody drugs comprises two main stages: the upstream process for antibody cultivation and the downstream process for antibody extraction. The domestic bio industry has excellent technology for the upstream process. However, it relies on the technology of foreign countries to execute downstream process such as affinity chromatography. Furthermore, there are no domestic companies capable of producing the equipment for affinity chromatography. High gradient magnetic separation technology using a high temperature superconducting magnet as a novel antibody separation and purification technology is introduced to substitute for the traditional technology of affinity chromatography. A specially designed magnetic filter was equipped in the bore of the superconducting magnet enabling the continuous magnetic separation of nano-sized paramagnetic beads that can be used as affinity magnetic nano beads for antibodies. To optimize the magnetic filter that captures superparamagnetic nanoparticles effectively, various shapes and materials were examined for the magnetic filter. The result of magnetic separation experiments show that the maximum separation and recovery ratio of superparamagnetic nanoparticles are 99.2 %, and 99.07 %, respectively under magnetic field (3 T) and flow rate (600 litter/hr).

森林內 落葉層의 含水量과 담뱃불에 의한 可燃性 (Moisture Content of Litter Layer and Its Combustibility by Cigarette Light in Forests)

  • 김관수;장인수;김수정
    • The Korean Journal of Ecology
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    • 제17권1호
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    • pp.1-9
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    • 1994
  • 본 연구는 산불의 근원이 된다고 하는 담배불에 의한 연소형태의 특징을 구명하고 그 현상을 해명하여 산불 방지대책의 연구자료로 기여하자는데 있다. 국산 담배 종류별 흡연자를 조사한 결과 흡연량은 개당 30mm였고, 흡연하고 버려지는 담배의 길이는 30mm정도여서 꽁초의 자연연소시간은 약 10분이 소요된다. 삼림내 퇴적층은 평균 58.2mm였고, 퇴적물량은 인간간섭이 적은 선치산이 고우언화된 계룡산에 비하여 29.6%가 더 많다. 임내 지상 가연물량은 Pinus rigida, Quercus acutissmia, Larix leptolepis등은 수세가 왕성한 15년생과 20년생 조림지에서 가연물량이 평균 2.43kg과 2.55kg으로 다소 많았다. 가연물의 착화 및 발염상태는 함수량 2~6%의 시료(C)의 Zoysia japonica와 Populus X tomentiglandulosa는 5분 이내에 발염되고, 침엽수종인 Pinus rigida와 Larix leptolepis는 착화되어 불씨는 만들어지나 자체발염은 되지 않았으며, Zoysia Japonica와 Populus X tomentiglandulosark 함유되는 혼합고엽의 시료에서는 모두 발염되어 담배둘에 의한 산불은 Zoysia japonica와 같은 건초가 가장 위험한 화원이 되겠다.

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Tc-99m-MIBI 심근 SPECT에서 재구성필터의 차단주파수에 의한 인위적 관류결손의 정량적 평가 (Quantitative Analysis of Artifactual Perfusion Defects due to the Cutoff Frequencies of Reconstruction Filters in Tc-99m-MIBI Myocardial SPECT Images)

  • 곽철은;정준기;이명철
    • 대한의용생체공학회:의공학회지
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    • 제16권2호
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    • pp.231-238
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    • 1995
  • Tc-99m-MIBI 심근 SPECT에서 심근조직에 비하여 간섭취가 상대적으로 높고 이들이 서로 가까이에 위치해 있는 경우 단축단면상의 하위부 또는 하위중격부에서 발생하는 인위적 관류결손의 정도와 여과기의 차단주파수의 관계를 분석하였다. 이러한 영향은 단축단면상 뿐만 아니라 심근 극성지도에서도 관찰되는데, 심근단층상에서 계수분포가 균일하지 못하고 간과 같이 특정부위에 방사능의 집적도가 높은 경우 단층상 재구성시 차단 파수의 적절한 설정에 따라 이 효과를 줄일 수 있는 방법을 제안하였다. 본 연구에서 분석에 사용된 여과기는 저역통과여과기로 이를 사용하는 경우에는 차단주파수를 0.4Nyquist 이상으로 하면 인위적 관류결손의 정도를 충분히 줄일 수 있었다. 그러나 높은 차단주파수에서는 심근영상의 균일도가 떨어지고 배후방사능 및 기타 잡음요인이 효과적으로 제거되지 않기 때문에 적절한 차단주파수의 설정이 중요하며, 본 연구에 사용된 영상에서 여과방법에 따른 원주프로필의 변화가 미세하여 후처리방법을 사용하여 분석하였다. 또한 역투사방법이 비선형적이므로 특정 영상보다는 다양한 간-심근 방사능비에 따른 영상을 분석하여 비선형성을 배제한 연구가 향후 진행되어야 한다.

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Ecological Functions and Losses of Traditional Korean Village Groves

  • Lee, D.-W.;Park, C.-R.
    • 한국제4기학회지
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    • 제18권2호통권23호
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    • pp.65-66
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    • 2004
  • There have been groves, in many cases, along with hedgerows and remnant forests around a traditional Korean village. A village grove is very closely connected to the life of residents. Sometimes it was a holy place where important village festivals were held, and became a resting place for farmers, especially in sunny summer. As a matter of fact, it is noted that traditional Korean village groves had been fostered for many purpose as religion, Confucianism, scenery, sanitation, traffic guard, public security, agriculture, hunting, and military and public uses were included in Chosun Govemor General(1938). Village groves were usually located at the outlet of watershed inside which a village was built. In addition, village groves used to be established along part of mountain ranges, streams and streets. A unique type of village grove, called bibosoop was fostered especially where the outlet of watershed was largely opened. In other cases, it was placed where a part of mountain range was relatively low, or where village residents were likely to see ugly objects such as a huge cliff, stony upland with an unvegetated area and the like(Kim and Jang 1994). In a sense, a sheltebelt is a sort of bibosoop as it is a landscape element to complement places that are exposed to strong winds. However, it is comparable to other typical bibosoop that is situated at a topographically very specific zone of watershed. In this paper, we will address potential functions of Korean village groves from a perspective of modern landscape ecology and show current status of some remnants, based on preliminary surveys. A village grove functions as barrier or filter of objects such as water, nutrients, and other elements and habitat of wildlife (park et al. 2003, Lee 2004). The village grove slows down the flow of water and air, maintains soil moisture an hinders soil erosion, enabling cultivation of crops and bringing up creatures nearby. It contributes to enhancing biodiversity. Birds rest on shrubby and woody trees of the element. Presumably, other organisms may also inhabit the village groves and take advantage of it when those move from a forest patch to others. Emerging insects acclimate themselves in the shade of the green space before they fly to sunny air. Besides the village grove acts as a component of agroforestry system as leaf litter is shed from a grove to an asjacent agricultural area, and transformed into green manure(Lee 2004). By the way, many of the landscape elements were destroyed or declined in Koea during the past several decades. The losses have been parallel or linked to environmental degradation. Unfortunately, we have a little reliable data as for how many groves have disappeared in Korea until now. There has been no complete census on the village groves in Korea, and the viewpoints of survey were to a degree different depending on surveyors. So, it is difficult to analyze the temporal and spatial change of village groves. Currently, national inventory data of Korean village groves are available in three reports. We reviewed the locations of village groves and arranged those according to the present administrative units, DONG. With the limited data, we found that at least 484 of village groves were recorded in South Korea. Among all provinces, village groves were most in Gyeongsanbuk-Do Province and least in Chungcheongbuk-Do Province(Table 1). This is a preliminary report prepared while some quantitative data regarding functions and lossers of the village groves are being collected. More detailed data will be introduced in the near future.

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