• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 Proceeding
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• pp.223-230
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• 2003

Feature-based similarity retrieval has become an important research issue in multimedia database systems. The features of multimedia data are useful for discriminating between multimedia objects (e 'g', documents, images, video, music score, etc.). For example, images are represented by their color histograms, texture vectors, and shape descriptors, and are usually high-dimensional data. The performance of conventional multidimensional data structures(e'g', R- Tree family, K-D-B tree, grid file, TV-tree) tends to deteriorate as the number of dimensions of feature vectors increases. The R＊-tree is the most successful variant of the R-tree. In this paper, we propose a SOM-based R＊-tree as a new indexing method for high-dimensional feature vectors.The SOM-based R＊-tree combines SOM and R＊-tree to achieve search performance more scalable to high dimensionalities. Self-Organizing Maps (SOMs) provide mapping from high-dimensional feature vectors onto a two dimensional space. The mapping preserves the topology of the feature vectors. The map is called a topological of the feature map, and preserves the mutual relationship (similarity) in the feature spaces of input data, clustering mutually similar feature vectors in neighboring nodes. Each node of the topological feature map holds a codebook vector. A best-matching-image-list. (BMIL) holds similar images that are closest to each codebook vector. In a topological feature map, there are empty nodes in which no image is classified. When we build an R＊-tree, we use codebook vectors of topological feature map which eliminates the empty nodes that cause unnecessary disk access and degrade retrieval performance. We experimentally compare the retrieval time cost of a SOM-based R＊-tree with that of an SOM and an R＊-tree using color feature vectors extracted from 40, 000 images. The result show that the SOM-based R＊-tree outperforms both the SOM and R＊-tree due to the reduction of the number of nodes required to build R＊-tree and retrieval time cost.

• International Journal of Industrial Entomology and Biomaterials
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• 제47권2호
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• pp.73-78
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• 2023

Currently, Hyphantira cunea Drury, the fall webworms (FWW), is one of the most severe insect pest for various landscaping trees and mulberry trees. In this study, we investigated whether FWW might be managed by Sodium saccharin (SAC) which is a food additive and not toxic to humans and environment. We found that FWW larvae treated with various concentrations of SAC showed dose-dependent delayed development and low survival rates. The lethal-concentration 50% of FWW larvae to SAC was 0.03 M. We also confirmed that SAC can be used to control FWW larvae attacking mulberry trees in the field. Compared to not-treated or tap-water-spraying control groups, SAC-spraying groups showed significantly higher mortality rates of FWW larvae (56.2%). Thus, SAC can be used for control FWW larvae in mulberry trees.

• 한국토양비료학회지
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• 제33권5호
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• pp.325-332
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• 2000

1998년 11월 18일에 $2.7{\times}2.7m$ 거리로 재식된 11년생 궁천조생온주 4주에 5 atom % 15N를 요소로 19.68 g 주-1의 N, $58kg\;ha^{-1}$의 $K_2O$을 시용하였고, 1999년 3월 22일에 104, 308, $62kg\;ha^{-1}$의 N, $P_2O_5$, $K_2O$를 6월 12일에 42 and $83kg\;ha^{-1}$의 N와, $K_2O$를 시용하여 재배한 후 1999년 6월 15일과 12월 8일에 각각 2주씩 굴취 해체하여 전질소 및 가을시용질소 함유량을 수체 부위별로 조사하였다. 과실, 잎줄기, 뿌리에의 전질소함유량의 분포비율은 6월 굴취 때에 각각 주당 전질소 총함유량(168.2g)의 11.9, 42.1, 29.7, 16.3%이었고, 12월 굴취 때에 각각 주당 전질소 총함유량 (169.8g)의 27.6, 36.4, 22.8. 13.1%이었다. 수체 질소 중 가을시용질소에서 유래된 질소의 비율은 두 굴취 시기 모두 새로 발생된 기관에서 현저히 높았다. 6월 굴취 때의 가을시용질소 회수율은 18.5%(3.63g 주-1)이었고, 주당 가을시용질소 총함유량의 21.1, 50.4, 21.5, 7.9%가 각각 과실 잎, 줄기, 뿌리에 분포되어 있었다. 12월 굴취 때의 가을시용질소 회수율은 17.0%(3.35g 주-1)이었고 가을시용질소 총함유량의 39.6, 40.5, 14.5, 5.3%가 각각 과실, 잎, 줄기, 뿌리에 분포되어 있다. 전질소에 비하여 두 시기 모두 가을시용질소에서 유래된 질소는 대사적으로 활발한 조직에 보다 많이 축적된 반면 오래된 조직에는 보다 적게 축적되었다.

• 한국대기환경학회지
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• 제22권6호
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• pp.791-798
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• 2006

In order to investigate the NVOC (Natural Volatile Organic Compound) emissions from White Oak, the emission rates of isoprene were measured according to season, weather conditions, and the age of the tree. The analysis of seasonal emission rates showed that the emission rates were the highest during summer followed by spring and fall. The emission rates during summer were found to be nearly 8 times greater than those during fall. In addition, it was observed that the emission rates of isoprene depends on PAR and temperature. Moreover, the effect of age on the emission rates was studied, and the White Oak in the age range of $21{\sim}30$ had higher emission rates than that in the range of $41{\sim}50$. Accordingly, the current result indicates that the isoprene emissions are affected by both meteorological parameter and the age of a tree.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.618-621
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• 2009

데스크탑 및 이동형 컴퓨터의 저장 장치를 지원하는 플래시 메모리는 비휘발성, 낮은 전력소모, 빠른 데이터 접근 속도 등의 장점이 있다. 하지만, 일반 RAM 메모리에 비하여 상대적으로 느린 연산 특성을 고려하여 기존의 전통적인 인덱스 관리 기법을 개선할 필요가 있다. 이를 위하여, 본 논문은 CHC-Tree 라고 하는 압축된 핫-콜드 클러스터링에 기반하는 새로운 인덱스 관리 기법을 제안한다. CHC-Tree는 인덱스 노드를 핫-콜드 세그먼트로 분류하며, 인덱스 노드의 키와 포인터를 압축한다. 또한, 실험 결과를 통하여 기존의 B-Tree 기반의 인덱스 관리 기법보다 인덱스 검색 및 인덱스 수정 연산에서 더 우수함을 확인하였다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 Proceeding
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• pp.50-56
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• 2003

In the development of complex software system, it is important to use hierarchical use case model due to the complex scope of development procedure. The use case model is core factor of the OMG (Object Management Group)'s UML (Unified Modeling Language) diagrams. In this paper, we propose a novel method to check syntactic consistency automatically in use case models at the different level of abstraction. This method is a rule-based approach which utilizes actor tree, use case tree and use case description. The proposed method is simulated on ITS (Intelligent Transportation System) architecture for the verification.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.313-316
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• 2000

Wavelet transform has specific properties for image coding. The property used at this Paper is clustering of significant coefficients across subband. These coefficients are classified in significant coefficient and insignificant coefficient on a threshold value, and symbolized EZW decreases symbol-position information using zero-trees, but threshold value fall for raising resolution, then coding cost of significant coefficients is expensive. To avoid this fact, this paper uses quad-tree representing coefficient-position information. a magnitude of significant coefficient is represented on matrix used at EZW. the proposed algorithm is hoped for raising a coding cost.

• The Korean Journal of Ecology
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• 제23권2호
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• pp.113-116
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• 2000

Different phenological patterns of leaf and fruit fall among native and non-native riparian species provide a spatially and temporally heterogeneous series of alternative food resources for detritivores. Relatively little is known about qualitative differences among these different riparian species. Rates of litter inputs, decomposition, and retention for different sources of riparian litter require long-term documentation. Species of freshwater shrimps, crabs. insects. and gastropods are known to consume a wide range of litter inputs but how these dynamic food webs function under changing climatic and land-use conditions is unknown, especially in tropical streams. On-going studies in the Luquillo Experimental Forest. Puerto Rico provide an example of how inputs of fronds and fruits from palms (Prestoea montana) serve as important foods and microhabitat for species of freshwater crabs and shrimp. Native riparian species such as Prestoea montana are commonly distributed in the Luquillo Mountains especially along steep slopes and stream banks. After tropical storms with high winds, the large fronds from these native riparian trees provide important inputs of leaf litter to the stream food web. In some streams, the input of ripe fruit from non-native trees such as Java plum (Syzigium jambos) also provides a major source of detrital food resources, especially during periods when fruit fall from native species of palms may be limited.

• 대한원격탐사학회지
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• 제20권3호
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• pp.197-205
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• 2004

Wetlands are lands with a mixture of water, herbaceous or woody vegetation and wet soil. And linear spectral mixture analysis (LSMA) is one of the most often used methods in handling the spectral mixture problem. This study aims to test LSMA is an enhanced routine for classification of wetland land-covers in Paldang reservoir and vicinity (paldang Reservoir) using Landsat TM and ETM+ imagery. In the LSMA process, reference endmembers were driven from scatter-plots of Landsat bands 3, 4 and 5, and a series of endmember models were developed based on green vegetation (GV), soil and water endmembers which are the main indicators of wetlands. To consider phenological characteristics of Paldang Reservoir, a soil endmember was subdivided into bright and dark soil endmembers in spring and a green vegetation (GV) endmember was subdivided into GV tree and GV herbaceous endmembers in fall. We found that LSMA fractions improved the classification accuracy of the wetland land-cover. Four endmember models provided better GV and soil discrimination and the root mean squared (RMS) errors were 0.011 and 0.0039, in spring and fall respectively. Phenologically, a fall image is more appropriate to classify wetland land-cover than spring's. The classification result using 4 endmember fractions of a fall image reached 85.2 and 74.2 percent of the producer's and user's accuracy respectively. This study shows that this routine will be an useful tool for identifying and monitoring the status of wetlands in Paldang Reservoir.

• 한국산림과학회지
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• 제90권1호
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• pp.10-18
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• 2001

오존 환경에 클론간 감수성을 비교하기 위하여 미류나무(Populus deltoides Marsh.) 10클론을 walk-in type인 4개의 chamber에 대조구, 50ppb, 100ppb, 150ppb 등 4가지 처리로 하루 8시간씩 21일간 계속하여 노출한 후 조기 낙엽율과 잎의 가시적 피해율을 조사하였다. 조기 낙엽율은 처리전과 비교할 때 저농도에서 고농도 순으로 처리농도에 따라 점진적으로 증가하여 150ppb 처리구에서는 50% 이상의 높은 낙엽율을 보였다. 잎의 가시적 피해는 대조구와 50ppb 처리구에서는 나타나지 않았으나, 100ppb 처리구에서는 피해잎 출현율(LA)은 17.3%, 피해면적(AA)은 6.5%로 본당 전체 피해율(LAA)은 1.6%로 나타났고, l50ppb 처리구에서는 피해잎 출현율 34.1%, 피해면적 17.5%로 전체 피해율 7.4%를 보였다. 잎의 가시적인 피해현상이 나타난 100ppb와 150ppb 처리구에서는 클론간에 피해의 차이를 보여 수종내 클론간의 감수성 차이를 확인할 수 있었다.