• Journal of Plant Biology
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• v.35 no.4
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• pp.385-392
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• 1992

여뀌속 Tovara절 식물은 매우 복잡한 양상의 형태변이를 나타내기 때문에 각 분류군의 한계 및 위치 성정, 계통적 유연관계 해석에 있어 많은 혼란이 나타나고 있다. 따라서 본 연구에서는 본 절 분류군에서 나타나는 형태 변이의 양상을 수리분류학적으로 분석하여, 각 분류군의 한계를 명확히 설정하고 그 분류학적 타당성을 검토하고자 하였다. 본 절 분류군의 주요 식별형질에 대한 주성분 분석을 수행한 결과, 본 절은 형태적으로 크게 P. virginianum, P. filiforme, P. neofiliforme의 3분류군으로 구분되며, 이들은 주로 잎의 형태에 의해 식별되는 것으로 밝혀졌다. 또한 P. virginianum var. glaberrimum은 그 분류학적 타당성이 없는 것으로 나타났으며, Tovara (=Polygonum) virginiana var. kachina는 형태적으로 볼 때 P. neofiliforme의 변종으로 취급하는 것이 타당한 것으로 판명되었다. Polygonum virginianum, P. filiforme, P. neofiliforme는 그 flavonoid 조성에 있어서도 명확한 차이를 나타내며, 이러한 결과를 종합해 볼 때 이들은 각각 독립된 종으로 인식하는 것이 타당한 것으로 판단된다.

• Korean Journal of Plant Taxonomy
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• v.37 no.3
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• pp.255-273
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• 2007

The morphological characters for 4 taxa of Korean Symplocaceae were examined. Based on morphological examination, numerical analysis was performed to clarify the taxonomic relationships among the taxa. It was found that epidermal characters of leaves, cellular deposition of petals, cellular boundary of petioles, growth of stigmas and pollen grains and their surfaces were useful diagonostic characters. From the results of PCA analysis, four taxa were grouped as species clusters including each populations. Four species of Symplocos were clustered as species groups with clear delimitation. Morphological, numerical, and palynological analyses supported the previous morphological studies on this family.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1115-1127
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• 2010

In order to increase the productivity in manufacturing TFT-LCD(thin film transistor-liquid crystal display), it is essential to classify defects that occur during the production and make an appropriate decision on whether the product with defects is scrapped or not. The decision mainly depends on classifying the defects accurately. In this paper, we present an effective classification method for film defects acquired in the panel production line by analyzing the intensity distribution and shape feature of the defects. We first generate a binary image for each defect by separating defect regions from background (non-defect) regions. Then, we extract various features from the defect regions such as the linearity of the defect, the intensity distribution, and the shape characteristics considering intensity, and construct a referential image database that stores those feature values. Finally, we determine the type of a defect by matching a defect image with a referential image in the database through the matching cost function between the two images. To verify the effectiveness of our method, we conducted a classification experiment using defect images acquired from real TFT-LCD production lines. Experimental results show that our method has achieved highly effective classification enough to be used in the production line.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.1
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• pp.13-19
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• 2010

In this paper, we study a new estimation system for the prediction of steam generator tube defects. In the previous research works, defect size estimators were independently designed for each defect types in order to estimate the defect size. As a result, the structure of estimation system is rather complex and the estimation performance gets worse if the classification performance is degraded for some reason. This paper studies a new estimation system that does not require the classification of defect types. Although the previous works are expected to achieve much better estimation performance than the proposed system since it uses the estimator specialized in each defect, the performance difference is not so large. Therefore, it is expected that the proposed estimator can be effectively used for the case where the defect type classification is imperfect.

• Korean Journal of Plant Taxonomy
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• v.45 no.2
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• pp.114-135
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• 2015

The taxa of Dryopteris subg. Erythrovariae are variable in morphology, resulting in taxonomic confusion in delimiting taxon boundaries. We examined the morphological characteristics of the Korean members of subg. Erythrovariae to clarify their taxonomic identities and relationships. The shapes of the blades, pinnae, and pinnule apices, the shapes and colors of the scales, and the positions of sori were useful for delimiting the Korean taxa of the subgenus. Based on the results of this study and evidence from previous studies, 13 taxa comprising 12 species and one variety of Dryopteris subg. Erythrovariae were recognized in Korea. Descriptions of all Korean taxa of the subg. Erythrovariae and a key to the species are provided. The descriptions presented here are based on field observations and the examination of some 1,000 specimens from the major herbaria of the world.

• Korean Journal of Plant Taxonomy
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• v.44 no.3
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• pp.191-201
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• 2014

In order to find useful taxonomic morphological characters, 17 taxa from East-Asia Astragalus and Oxytropis anertii were investigated. In this study, seed coat structure, fruit surface, and fruit anatomical structures were selected to classify the species in Astragalus. As a results, useful morphological and anatomical characters in East-Asia Astragalus were life cycle, leaflet shape, raceme, petal color, seed color, pod shape, absent or present of hairs in pod surface, bent degree of dorsal suture, and thickness of endocarp. Using medicinal sources in China, A. floridus, A. membranaceus, A. membranaceus var. mongholicus and A. tongolensis were formed same group. However, these were not completely consensus in the morphological characters. The other hand, A. koraiensis and A. sikokianus, which have controversial taxonomic issue, have clearly no differences morphological characters each other. Therefore, A. koraiensis, A. sikokianus, and A. bhotanensis should be conducted a comparative study on the DNA sequences and molecular cytology in order to clarify the taxonomic treatments in the near future.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.27-35
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• 2009

In this paper, we study the classification of steam generator tube defects using an improved feature extraction. We consider 4 axisymmetric defect patterns of tube: I-In type, I-Out type, V-In type, and V-Out type. Through numerical analysis program based on finite element modeling, 400 ECT signals are generated by varying width and depth of each defect type. From those generated ECT signals, we propose new feature vectors that include an angle between the two points where the Maximum impedance and half the Maximum impedance, and angles between Maximum impedance point and 10%, 20%, 30%, 40% of Maximum impedance points. Also, multi-layer perceptron with one hidden layer is used to classify the defect patterns. Through the computer simulation study, it is shown that the proposed method achieves an improved defect classification performance in terms of Maximum Error and mean square Error.

• Korean Journal of Plant Taxonomy
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• v.42 no.1
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• pp.1-12
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• 2012

To clarify the morphological variations of Galium, its morphological characteristics were examined using maximum parsimony analysis. The key characteristics as well as the range of variation in each characteristic were investigated at the species level and were employed to elucidate the relationships between the taxa. This study confirmed that species belonging to genus Galium formed a monophyletic group and comprised two main clades. Sect. Cymogaliae and sect. Leptogalium are polyphyly groups, and other sections are monophyletic group. This study also suggests that the fruit hairs, the types of petal apexes, and the colors of the petals are the most valuable taxonomic characteristics for differentiating different sections. The numbers of the leaves and leaf shape provide useful taxonomic characteristics for the identification of different species.

• Journal of the Korean Society for Nondestructive Testing
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• v.13 no.2
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• pp.11-19
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• 1993

It is very essential to get the accurate classification of defects in primary pressure vessel weld for the safety of nuclear power plant. The signal analysis using the digital signal processing and pattern recognition is performed to classify UT defects extracting feature vector from ultrasonic signals. The minimum distance classifier and the maximum likelihood classifier based on statistics were applied in this experiment to discriminate ultrasonics data obtained form both the training specimens (slit, hole) and the testing specimens(crack, slag). The classification rate was measured using pattern classifier. Results of this study show the promise in solving the many flaw classification problems that exist today.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.411-411
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• 2019

지형학적으로 다양한 형상을 가지고 있는 하천유역은 지역적 조건에 따라 뚜렷한 특징을 나타낸다. 이러한 조건은 하천유역의 발달 및 수문학적 특징에 영향을 미친다. 금회 연구는 여러 가지 유역의 특징 중 유역을 대표할 만한 특징을 이용하여 간단하고 유용한 하천 유역 분류 기법을 제시하였다. 하천유역의 여러 특징 중 지류교차각(Tributary Junction Angle)은 유역을 분석하기 위해 많이 사용되었으며 다른 특징들과 함께 유역 구분을 위해 분석되어 왔다. 하지만, 지류교차각만 이용하여 유역 분류를 제시하는 기법은 연구되지 않았다. 하천유역 분류 기법 제시를 위해 수지형 유역, 평행형 유역, 부채형 유역, 직사각형 유역, 격자형 유역 등 5가지의 형태를 중심으로 50개의 하천유역을 사용하였고, 지류교차각의 Beta Distribution 모델을 적용하여 매개변수 추정치 산정 후 유역 분류를 위한 분석을 실시하였다. 매개변수 추정치는 각 유역 형태 구분을 위해 적용되었고, 이후 Support Vector Machines를 이용하여 하천유역 형태를 분류하도록 하였다. 분석을 통한 결과는 일반적인 통계기법과 다른 유역형태 구분 기법을 이용하여 검증하였다. 제안된 기법은 수지형, 평행형, 부채형 유역 형태들에 대하여 정확하게 분류할 수 있으며, 얻어지는 결과는 중요한 수문학적 정보 제공에 사용 될 것으로 판단된다. 금회 연구를 통해 Beta 분포형의 매개변수 추정치는 하천유역 분류 적용에 유용하게 사용 될 수 있음을 확인하였고, 하나의 주요 유역 인자로 유역 구분이 가능함을 제시하였다. 향후 연구로는 하천유역 분류를 통해 수문학적인 동질 유역을 구분하여 수문모델의 수행능력을 향상 시킬 수 있는 수문모델 분석과 개발에 적용 될 수 있을 것이다.