두개강내 역형성 성상세포종의 신경교육종으로 전환 -증례보고-

오윤식 ( Yoon Sik Oh ),김충현 ( Choong Hyun Kim ),백광흠 ( Kwang Hum Bak ),김재민 ( Jae Min Kim ) 대한뇌종양학회·대한신경종양학회·대한소아뇌종양학회 2007 대한뇌종양학회지 Vol.6 No.2

Gliosarcoma is a rare biphasic central nervous system malignancy that are composed of distinct sarcomatous and glial neoplastic proportion. We report a rare case with transformation of recurrent anaplastic astrocytoma into gliosarcoma. A 26-year-old male patient presented with headache. He was diagnosed as neurofibromatosis type I, 5 years ago. Magnetic resonance image(MRI) showed a well-demarcated, heterogeneously enhancing space-occupying lesion in the right frontal lobe. He underwent an osteoplastic craniotomy with radical tumor resection. Histopathology of tumor showed heterogeneous pleomorphic nuclear hyperchromatism corresponding with anaplastic astrocytoma. He was taken radiotherapy and chemotherapy. Subsequent follow-up period of 11 months was uneventful until he developed a generalized tonic clonic seizure, along progressively worsening headache. MRI showed tumor recurrence in the right frontal lobe. Re-exploration was carried out and gross total resection was done. Pathological examination displayed a biphasic pattern of glial and sarcomatous component suggesting gliosarcoma. This is an uncommon case with transformation of anaplastic astrocytoma into gliosarcoma, and we discussed with pertinent literatures.

제주도 해산 녹조 (綠藻) 대마디말속 (屬) ( Cladophora ) 식물 삼종의 분류학적 주해

오윤식(Yoon Sik Oh),이인규(In Kyu Lee),이용필(Yong Pil Lee) 한국식물학회 1990 Journal of Plant Biology Vol.33 No.2

Three marine species of Cladophora (Cladophoraceae, Chlorophyta) commonly occurred on the coast of Cheju Island, Cladophora conchopheria Sakai, C. gracilis (Griff.) Ku´tzing and C. urightiana Harvey were described morphologically, considering their taxonomic characters. C. conchopheria Sakai, specifically growing on the surface of Lunella coronata, is a very minute plant of 550-990 ㎛ in height and has intracuticular adventitious rhizoids borne from the lower portion of the first to fourth segments. C. gracilis occurs on calm habitat and shows a pseudosympodial growth with pectinate branchlets. C. wrightiana always produces protoplasmic protuberances at the node of middle portion of thallus. It grows to 30 ㎝ or more in height and is dark green in subtidal bottom.

빅데이터 K-평균 클러스터링을 위한 RHadoop 플랫폼

신지은,오윤식,임동훈,Shin, Ji Eun,Oh, Yoon Sik,Lim, Dong Hoon 한국데이터정보과학회 2016 한국데이터정보과학회지 Vol.27 No.3

RHadoop is a collection of R packages that allow users to manage and analyze data with Hadoop. In this paper, we implement K-Means algorithm based on MapReduce framework with RHadoop to make the clustering method applicable to large scale data. The main idea introduces a combiner as a function of our map output to decrease the amount of data needed to be processed by reducers. We showed that our K-Means algorithm using RHadoop with combiner was faster than regular algorithm without combiner as the size of data set increases. We also implemented Elbow method with MapReduce for finding the optimum number of clusters for K-Means clustering on large dataset. Comparison with our MapReduce implementation of Elbow method and classical kmeans() in R with small data showed similar results. 본 논문에서는 대용량 데이터를 처리 및 분석하기 위해 RHadoop 플랫폼에서 실제 데이터와 모의 실험 데이터를 가지고 K-평균 클러스터링을 구현하고, MapReduce의 컴바이너 사용여부에 따른 처리 속도를 비교하고자 한다. 또한, K-평균 클러스터링에서 최적의 군집수 결정방법을 MapReduce 프로그램으로 구현하여 실제 데이터에 적용하고자 한다. 그리고 제안된 RHadoop 플랫폼의 확장 가능성을 보이기 위해 실제 데이터에서 R의 기본 패키지에서 kmeans() 함수와 bigmemory 패키지 상에서 유용한 bigkmeans() 함수와 처리 속도를 비교하고자 한다.

개선된 이동평균법을 이용한 ESS 용량 산정 방법에 관한 연구

김지수(Ji-Soo Kim),오윤식(Yun-Sik Oh),조규정(Gyu-Jung Cho),김민성(Min-Sung Kim),김철환(Chul-Hwan Kim),김윤상(Yoon-Sang Kim) 한국조명·전기설비학회 2017 한국조명·전기설비학회 학술대회논문집 Vol.2017 No.5

한국산 해조류의 주해 (2)

이인규(In Kyu Lee),오윤식(Yoon Sik Oh),최도성(Do Sung Choi),김광훈(Gwang Hoon Kim) 한국식물학회 1988 Journal of Plant Biology Vol.31 No.2

Four species of marine algae, 1 green and 3 red algae, were newly found in Korea from Cheju Island and its vicinities in course of floristic survey. Three of them, Antithamnion callocladus, Balliella crouanioides, and Caulerpa ambigua, were collected from subtidal zone and the other, Choreonema thuretii, from intertidal zone.

유방암 분류 성능 향상을 위한 배깅 서포트 벡터 머신

임진수 ( Jin Soo Lim ),오윤식 ( Yoon Sik Oh ),임동훈 ( Dong Hoon Lim ) 한국보건정보통계학회(구 한국보건통계학회) 2014 보건정보통계학회지 Vol.39 No.1

Objectives: We proposed bagging SVM which constructs SVM ensembles using bagging for improving breast cancer classification. Methods: Each individual SVM was trained independently using the randomly chosen training samples via a bootstrap technique. Then, they were aggregated into to make a collective decision in aggregation strategy such as the majority voting. We compared the proposed bagging SVM model with existing single models such as discriminant analysis, logistic regression analysis, decision tree, support vector machines for two UCI data and simulated data. Performance of these techniques was compared through accuracy, positive predictive value, negative predictive value, sensitivity, specificity and F-score. Results: Experimental results for two UCI data and the simulated data showed that the proposed bagging SVM model outperformed single SVM, discriminant analysis, logistic regression analysis, decision tree and neural network in terms of various performance measures. Conclusions: We proposed bagging SVM for improving breast cancer classification. The bagging SVM ensembles outperformed existing single models for all applications in terms of various performance measures.

한국산 갈조식물 지충이의 지리적 형태변이

김상일 ( Sang Il Kim ),오윤식 ( Yoon Sik Oh ),원남일 ( Nam-il Won ),박상률 ( Sang Rul Park ) 한국환경생물학회 2014 환경생물 : 환경생물학회지 Vol.32 No.4

이번 연구는 한국산 지충이 [Sargassum thunbergii(Mertens ex Roth) Kuntze]의 지리적 형태변이를 확인하고, 형태변이에 따른 품종의 구분에 대하여 분류학적 재검토를 시도하였다. 동해, 서해와 남해안에 분포하는 지충이개체군의 지리적 형태변이를 조사하기 위해서 개체가 가장 성숙한 시기인 봄철에 채집하였다. 지충이의 관찰대상형질은 부착기, 줄기의 길이와 직경, 체장, 중심가지의 직경, 마디간격, 측지의 길이와 직경, 잎의 길이와 폭 및 두께, 기낭의 길이와 직경, 기낭 자루와 기낭 돌기의 길이,생식기탁의 길이와 직경, 질감이었다. 서해안의 지충이는 엽체가 짧고 가늘며, 마디간격이 넓어서 성긴 느낌이고 질감이 부드러워 다른 두 해역의 지충이와는 다른 형태적 특징을 보였다. 동해안의 지충이는 체장이 서해안의것과 비슷하지만 중심가지와 측지가 굵어서 질감이 거칠고, 측지가 없거나 매우 짧은 것도 있으며, 잎과 기낭이다른 해역에 비해 컸다. 남해안의 지충이는 체장과 측지가 가장 길고 잎과 기낭이 짧은 것이 특징이었다. 동해안북부에서 채집된 개체들은 f. latifolium과 형질이 유사하였다. 그러나 다른 해역에서는 네 품종의 원기재와 정확히 일치하지 않아 품종을 구분하는 식별형질은 한국산지충이의 형태 변이에 적용할 수 없었다. 따라서 생육지에 따라 나타나는 지충이의 다양한 형태변이는 종 이하의 분류군으로 나누는 것보다는 생육지 환경조건에 따른변이체로 보는 것이 타당할 것으로 사료된다. In this study, we investigated the effect of geographical variations on Sargassum thunbergii morphology to make a taxonomic reconsideration about infraspecific taxa in this species. In order to examine the morphological characteristics of S. thunbergii, total 27 matured and morphologically intact thalli were collected from the east, west and south coast in spring 2011. Interestingly, it was observed that the species populations on the west coast were characterized by short, thin and coarse thallus, and soft texture. However, the populations on the east coast showed thicker thallus, larger leaf and vesicle, and tougher texture. Thallus height of S. thunbergii was found to be similar at both east and west coast. Further, the height of the thallus and lateral branch of the species populations residing south coast were highest whereas the size of leaf and vesicle are shortest,in comparison with east and west coast species. Although morphological characteristics of the north east coast populations corresponded to the original description of S. thunbergii f. latifolium, we could not find exact morphological features and diagnostic characters to distinguish form in S. thunbergii. These results indicated that it is not the optimal characteristics to identify infraspecific form in this species. In contrast, morphological variations may signify the adaptation of this species to local environmental factors. Thus, we recommend that intraspecific morphological variation of S. thunbergii should be carefully used to identify infraspecific taxa.

AHP기법을 통한 KTX 수송경쟁력 분석에 관한 연구

김채원(Kim, Chae-Won),오윤식(Oh, Yoon-Sik),김대희(Kim, Dae-Hee) 국제관광산업학회 2016 국제관광산업연구 Vol.9 No.2

The AHP approach has been proven to be excellent for developing evaluation items for high-speed transport competitiveness. It aims to compare relative comparisons, expert surveys, and best practices. To evaluate the indicators, the method of AHP was applied to Railway specialists. Experts assessed the importance of all the indicators. Depending on the pairs of measurements on all indices based on the stratum structure, and the weight applied, the weight indices show the rank of all metrics. In this study, we selected the high-speed transport competitiveness index and evaluated the Analytic Assessment and indexing results to each station using the index. The transport competitiveness here is defined as the “ service level of the transportation and infrastructure of means of transportation from origin to destination “ to the destination.

한국산 미기록 해조 2종(Phyllodictyon anadtomosans 및 Saccharina ochotensis)에 대한 주해

황미숙 ( Mi Sook Hwang ),오윤식 ( Yoon Sik Oh ) 한국수산과학회 2013 한국수산과학회지 Vol.46 No.1

Phyllodictyon anastomosans (Harvey) Kraft et MJ. Wynne and Saccharina ochotensis (Miyabe) E.E. Lane c. Mayes, Druehl et G.W.Saunders are first reconded in Korea. A pantropical green alga, P. anastomosans was col- lected on a rock wall in the subtital zone of Jeju lsland. This species has very tiny fan-shaped and netted thalli that are green in color A cold temperate brown alga, P.ochotensis has very thick and leathery thalli that are deep brown in color. Morphological characteistics and habitats of these species are described with taxonomic accounts.

제주도산 홍조 아프리카바다표고(Peyssonnelia capensis Montagne)의 분류학적 특성

강승주,이재완,이욱재,오윤식,이해복,Kang, Seung-Ju,Lee, Jae-Wan,Lee, Wook-Jae,Oh, Yoon-Sik,Lee, Hae-Bok 한국조류학회(藻類) 2006 ALGAE Vol.21 No.2

The characteristics of Peyssonnelia capensis Montagne (Peyssonneliaceae, Rhodophyta) from Jeju Island were investigated in order to clarify the species entity and re-evaluate taxonomic position. The morphological variations of the Peyssonnelia capensis from Jeju Island were divided into two types, the thin thallus type and the thick thallus type. The thin thallus type is characterized by thin, soft, orbicular, slightly lobed thallus with entire to undulate margin, and compact rhizoids. The thick thallus type has thick and stiff thallus with sinuate margin and scattered rhizoids, and has more branches than the thin thallus type. The basal layer and the epithallium of thin thallus type are similar to those of thick thallus types in their structure. However, the hypothallial cells of the thick thallus type are longer than those of the thin thallus type. The erect filament of thick thallus type has more cells than those of the thin thallus type. Tetrasporangial nemathecia are distinctly protruded. Mature tetrasporangia of this species are divided cruciately into four spores as those of other Peyssonneliaceae. In addition to their morphological and anatomical distinctness between two types, the nucleotide sequence analyses of SSU and ITS2 region make no differences among populations from Jeju and other localities in Korea. Therefore these two morphological variation may not base on genetic variation.