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      • KCI등재

        상향식 계층분류의 최적화 된 병합을 위한 후처리분석과 피드백 알고리즘

        최윤정,박승수,Choi, Yun-Jeong,Park, Seung-Soo 한국정보처리학회 2010 정보처리학회논문지B Vol.17 No.2

        본 논문은 자동화된 분류시스템의 성능향상을 위한 것으로 오분류율이 높은 불확실성이 강한 문서들의 범주결정방식을 개선하기 위한 후처리분석 방법과 피드백 알고리즘을 제안한다. 전통적인 분류시스템에서 분류의 정확성을 결정하는 요인으로 학습방법과 분류모델, 그리고 데이터의 특성을 들 수 있다. 특성들이 일부 공유되어 있거나 다의적인 특성들이 풍부한 문서들의 분류문제는 정형화된 데이터들에서 보다 심화된 분석과정이 요구된다. 특히 단순히 최상위 항목으로 지정하는 기존의 결정방법이 분류의 정확도를 저하시키는 직접적인 요인이 되므로 학습방법의 개선과 함께 분류모델을 적용한 이후의 결과 값인 순위정보 리스트의 관계를 분석하는 작업이 필요하다. 본 연구에서는 경계범주의 자동탐색기법으로 확장된 학습체계를 제안한 이전 연구의 후속작업으로써, 최종 범주를 결정하기까지의 후처리분석 방법과 이전의 학습단계로 피드백하여 신뢰성을 높일 수 있는 알고리즘을 제안하고 있다. 실험결과에서는 제안된 범주결정방식을 적용한 후 1회의 피드백을 수행하였을 때의 결과들을 단계적이고 종합적으로 분석함으로써 본 연구의 타당성과 정확성을 보인다. This paper shows a reinforcement post-processing method and feedback algorithm for improvement of assigning method in classification. Especially, we focused on complex documents that are generally considered to be hard to classify. A basis factors in traditional classification system are training methodology, classification models and features of documents. The classification problem of the documents containing shared features and multiple meanings, should be deeply mined or analyzed than general formatted data. To address the problems of these document, we proposed a method to expand classification scheme using decision boundary detected automatically in our previous studies. The assigning method that a document simply decides to the top ranked category, is a main factor that we focus on. In this paper, we propose a post-processing method and feedback algorithm to analyze the relevance of ranked list. In experiments, we applied our post-processing method and one time feedback algorithm to complex documents. The experimental results show that our system does not need to change the classification algorithm itself to improve the accuracy and flexibility.

      • KCI등재
      • KCI등재

        경계범주 자동탐색에 의한 확장된 학습체계 구성방법

        최윤정,지정규,박승수,Choi, Yun-Jeong,Jee, Jeong-Gyu,Park, Seung-Soo 한국정보처리학회 2009 정보처리학회논문지B Vol.16 No.6

        본 논문은 기존의 목표항목만을 위주로 한 학습체계에서 발생하는 오분류 문제의 해결을 위해 기존의 학습체계에 경계항목을 자동으로 탐 색하여 포함시켜 확대시키는 방법을 제안하고 있다. 여러 주제에 걸쳐 다양한 내용을 다루는 복잡한 문서들은 확실히 어느 범주로 분류해야 할 지 판가름하기 어려운 성질인 모호성이 강하다. 이러한 경우 모든 경우들을 정확히 구분할 수 있는 최적의 경계를 찾는 일은 더욱 어려운 일이 다. 복잡하고 불확실성이 높은 데이터들의 특징은 대부분 분류 경계영역에 위치하므로 이러한 분류경계의 데이터들을 새로운 학습 항목으로 인 식시키도록 하는 것이 필요하다. 본 연구에서는 주어진 목표항목 사이의 경계항목을 자동으로 탐색하여 학습체계에 추가하는 학습 체계 확장 알고리즘을 제시하고, 의도적인 학습오류를 발생시킨 후 기존방법과의 비교실험을 수행함으로써 제안방법의 정확성과 안정성을 비교하였다. 실 험결과 경계범주를 포함하여 학습 체계를 확장시켰을 때의 예측력은 기존 0.70에서 0.86으로 약 24% 향상 되었고, 오류를 포함시켰을 때의 예 측력은 기존 0.52에서 0.79로 약 49% 향상되었다. This paper shows a reinforced construction scheme of training data for improvement of text classification by automatic search of boundary category. The documents laid on boundary area are usually misclassified as they are including multiple topics and features. which is the main factor that we focus on. In this paper, we propose an automated exploring methodology of optimal boundary category based on previous research. We consider the boundary area among target categories to new category to be required training, which are then added to the target category sementically. In experiments, we applied our method to complex documents by intentionally making errors in training process. The experimental results show that our system has high accuracy and reliability in noisy environment.

      • KCI등재

        백내장이 동반된 녹내장 환자에서 수정체유화섬유주절제술과 섬유절제술의 치료효과 비교

        최윤정,DouglasJ,Rhee,최규룡,Yun Jeong Choi,Douglas J,Rhee,Kyu-Ryong Choi 대한안과학회 2011 대한안과학회지 Vol.52 No.11

        Purpose: To compare the treatment outcome and complications of phacotrabeculectomy and trabeculectomy in patients with glaucoma and cataracts. Methods: The authors of the present study retrospectively reviewed the records of 56 eyes that underwent phacotrabeculectomy and trabeculectomy with mitomycin-C between March 2006 and December 2009 in patients with glaucoma and cataracts. The change of intraocular pressure (IOP) and number of glaucoma medications up to 24 months postoperatively were compared and the treatment failure rate as well as postoperative complications analyzed. Results: IOP and number of glaucoma medications at 24 months after surgery were similar in the 2 groups. Additionally, both groups showed a significant decrease in IOP and number of glaucoma medications after surgery. The cumulative failure rates, frequency and distribution of postoperative complications were also similar in both groups and conjunctival bleb leak was the most common complication. Conclusions: Both phacotrabeculectomy and trabeculectomy showed long-term IOP reduction and a similar failure rate and complications. Therefore, both can be considered as a primary surgical treatment in patients with glaucoma and cataracts. In patients who need strict IOP control, trabeculectomy can be preferentially considered. If patients have visually significant cataracts or greater visual needs, phacotrabeculectomy can be considered. J Korean Ophthalmol Soc 2011;52(11):1308-1317

      • KCI등재후보

        Identification of genomic regions associated with piglet survival and mortality

        최윤정,김상욱,윤준호,Bong-Hwan Choi,Tae-Hun Kim,김관석 충북대학교 동물의학연구소 2014 Journal of Biomedical and Translational Research Vol.15 No.2

        One of the major problems in the modern pig in- dustry is infectious disease. Susceptibility to infec- tious diseases is influenced by both constitutional (e.g. genotype, age, gender, and reproductive status) and environmental factors (e.g. nutrition, management, infections, and other forms of stress). Genetic varia- tions within individual animals or herds can cause dif- ferences in the execution of immune functions against infectious agents in domestic pigs. The objectives of the present study were to identify genetic factor(s) responsible for piglet survival and mortality under commercial field conditions with infectious diseases as well as determine QTL regions for immune capac- ity in a pig reference family. Sex ratio was examined between normal grown and presumed dead groups of F 2 animals generated by Korean native pigs (KNP) and Yorkshire (YS) breeds. The ratio of males was significantly higher in the presumed dead group than in the normal grown group. In order to study genetic factors associated with presumed mortality under dis- ease outbreak, allelic frequencies of 239 single nucleo- tide polymorphisms (SNPs) were compared between normal grown and presumed dead groups. Exactly 22 SNPs showed significant differences in their allelic frequencies between the two groups, and four of them were validated with another commercial population divided by normal and emaciated pigs. Furthermore, the relationships between 239 SNPs and immune- related traits were studied. These results demonstrate that identification of genetic components of animal im- mune systems and susceptibility to infectious diseases is possible and will be useful to improve disease resis- tance in individuals as well as in breeding programs.

      • KCI등재

        Comparison of the mechanical properties and microstructures of fractured surface for Co-Cr alloy fabricated by conventional cast, 3-D printing laser-sintered and CAD/CAM milled techniques

        최윤정,곽재영,허성주,김성균,안진수,박동수,Choi, Yun-Jung,Koak, Jai-Young,Heo, Seong-Joo,Kim, Seong-Kyun,Ahn, Jin-Soo,Park, Dong-Soo The Korean Academy of Prosthodonitics 2014 대한치과보철학회지 Vol.52 No.2

        연구 목적: 본 연구의 목적은 주조, 3-D printing laser sintered 및CAD/CAM technology를 이용한 milling 방법으로 제작된 치과용 코발트-크롬 합금의 기계적 물성을 비교하고 파절 단면의 미세 구조를 살펴보는 데 있다. 이를 통해 새롭게 소개된 제작 기법 - 3D-printing laser sintered - 이 치과용 합금 제작으로 적합한 지 알아보고자 한다. 연구 재료 및 방법: 36개의 flat disc 모양의 시편을 제작하여 제작 방법에 따라 세 집단으로 나누었다; 주조 방식으로 제작한 12개, laser sintering 방법으로 12개, CAD/CAM milling 방법으로 12개의 시편을 제작하여 표면 경도 시험을 시행하였다. 또한 각 집단 별로 12개의 dumbbell 모양의 시편을 제작하여 인장 강도 시험을 시행하였다. 통계량이 비모 수적 통계 분포를 보였으므로 Kruskal-Wallis 검정을 이용하여 각 실험군의 인장 강도 시험 결과를 비교했으며, 통계적 유의 수준은P=.05로 설정하여 Mann-Whitney 및 Bonferroni 사후 검정을 시행하였다. 전자 주사 현미경을 사용하여 파절 단면의 미세 구조를 관찰하였다. 결과: Vickers hardness test에서 세 집단간에 모두 유의한 차이가 있었고, 주조 방식으로 제작된 실험군에서 가장 큰 표면 경도(455.88 Hv)가, CAD/CAM milling으로 제작된 실험군에서 가장 낮은 표면 경도(243.40 Hv)를 나타냈다. 최대 인장 강도, 0.2% 항복강도, elongation 및 elastic modulus에서 세 집단간에 모두 유의한 차이가 나타났으며, CAD/CAM milling으로 제작한 실험군에서 가장 높은 최대 인장 강도(1442.94 MPa)가, laser sintered 실험군에서 가장 큰 0.2% 항복 강도(1136.15 MPa)가 나타났다. 파절 단면의 전자 주사 현미경 관찰 결과, 주조 시편에서는 독특한 성긴 모양과 전형적인 주조 다공성 구조가 관찰되었고, laser sintered 시편에서는 편평한 면을 동반한 거친 결정 구조가, 그리고 milled 시편에서는 균일하고 규칙적인 치밀 미세 구조가 나타났다. 결론: 서로 다른 제작 방법은 코발트-크롬 합금의 물리적 성질과 파절 단면의 미세 구조에 영향을 미쳤다. 주조 방식으로 제작된 시편에서 가장 큰 표면 경도가, milling으로 제작된 시편에서 가장 큰 인장 강도를 나타냈으며, 본 연구의 모든 실험군에서 치과용 합금의 ISO 기준에 부합하는 물성을 보였다. Purpose: The purpose of present study is to compare mechanical properties and microstructural characteristics of fractured surface for cast, 3-D printing laser sintered and CAD/CAM milled cobalt-chromium (Co-Cr) alloy specimens and to investigate whether laser sintered technique is adequate for dental applications. Materials and methods: Thirty six flat disc shape Co-Cr alloy specimens were fabricated for surface hardness test and divided into three groups according to the manufacturing methods; 12 specimens for casting (n=12), 12 specimens for laser sintered technology (n=12) and 12 specimens for milled technology (n=12). Twelve dumbbell shape specimens for each group were also fabricated for a tensile test. Statistical comparisons of the mechanical properties for the alloys were performed by Kruskal-Wallis test followed by Mann-Whitney and Bonferroni test. The microstructural characteristics of fractured surfaces were examined using SEM. Results: There were significant differences in the mean Vickers hardness values between all groups and the cast specimen showed the highest (455.88 Hv) while the CAD/CAM milled specimen showed the lowest (243.40 Hv). Significant differences were found among the three groups for ultimate tensile strength, 0.2% yield stress, elongation, and elastic modulus. The highest ultimate tensile strength value (1442.94 MPa) was shown in the milled group and the highest 0.2% yield strength (1136.15 MPa) was shown in the laser sintered group. Conclusion: Different manufacturing methods influence the mechanical properties and microstructure of the fractured surfaces in Co-Cr alloys. The cast Co-Cr alloy specimens showed the highest Vickers hardness, and the CAD/CAM milled specimens revealed the highest tensile strength value. All alloys represent adequate mechanical properties satisfying the ISO standards of dental alloy.

      • KCI등재

        사군자탕(四君子湯) 및 사물탕(四物湯)이 methotrexate로 유도(誘導)된 흰쥐의 면역기능저하(免疫機能低下)에 미치는 영향(影響)

        최윤정,김장현,Choi Yun-Jung,Kim Jang-Hyun 대한한방소아과학회 1999 대한한방소아과학회지 Vol.13 No.1

        The effects of Sagunjatang and Samultang on the immunosuppression induced by methotrexate(MTX) in rats were investigated in this study. The multiple parameters of immunity assessed in each rats included leukocyte count, lymphocyte rate, the number of lymphocyte in tibial bone marrow, contact hypersensitivity to DNFB, morphological change of thymocyte and IgG antibody on SDS-PAGE. Sprague-Dawley male rats were used and divided into five groups at random. Group A was normal control. Group B, the MTX treatment control, was injected i.v. with 2mg/kg of on days 9, 11 after sensitization with SRBC on 5th day. Group C, the experimental control, was treated Sagunjatang for 18days and MTX. Group D was treated Samultang for 18days and MTX. Group E was treated Sagunjatang-Samultang for 18days and MTX. The dosage of Sagunjatang and Samultang was $1m{\ell}/day$ respectively. In the case of Group E, rats Were fed Sagunjatang $1m{\ell}$ in the morning and Samultang $1m{\ell}$ in the afternoon. The results are summarized as follows: 1. Leukocyte count in rats induced by intravenous sensitization with SRBC was decreased significantly in Group E. 2. Leukocyte counts of 2weeks later after being treated MTX were increased significantly in Groups C and D. 3. Lymphocyte rate in rats induced by intravenous sensitization with SRBC wasn't changed significantly in all the experimental groups. 4. Lymphocyte rate of 2weeks. later after being treated MTX was increased significantly in Group D. 5. The number of lymphocyte in tibial bone marrow was incereased significantly in Group C. 6. Contact hypersensitivity wasn't changed significantly in all the experimental groups. 7. Morphological finding of thymocyte in group C was similar to normal group as compared with control group. 8. Purified IgG of all the experimental groups showed two bands of 50,000 and 25,000 on SDS-PAGE. But there was no difference among experimental groups.

      • KCI등재

        학교교실의 냉방시 실내열.공기환경 실태

        최윤정,정연홍,이선아,김혜경,황진아,Choi, Yoon-Jung,Jeong, Youn-Hong,Lee, Seon-A,Kim, Hye-Kyeong,Hwang, Jin-A 한국주거학회 2007 한국주거학회 논문집 Vol.18 No.4

        The purpose of this study were to make clear the present condition of indoor thermal and air environment by cooling in school classrooms and to analyze the relation of the living conditions with indoor environment. The measurements on physical elements and observations on living conditions were carried out in 6 classrooms of 3 middle or high schools. Measuring elements were indoor temperature, relative humidity, PM10 and $CO_2$ concentration. As results, the averages of indoor temperature each classrooms were $24.9{\sim}26.6^{\circ}C$. Most of classrooms were lower than the Maintenance standard $(26{\sim}28^{\circ}C)$ of School Health Law. The means of relative humidity were $51.3{\sim}72%$, all classrooms were ranged within the standard $(30{\sim}80%)$. The means of PM10 concentration were $3.5{\sim}23.1{\mu}g/m^3$, all classrooms were kept within the standard $(100{\mu}g/m^3)$. The means of $CO_2$ concentration were $1218.7{\sim}4705.4ppm$, all classrooms were exceed the standard (1,000ppm). The results of analysis on relations of living conditions with the physical elements are as follow; the air conditioner set of temperature, windows and doors opening elapsed time, the number of students in classrooms and activities of students had certain effect on indoor environment.

      • KCI등재

        대학교 학생식당의 실내소음 실태 및 원인 분석 사례연구

        최윤정,이선아,김혜경,Choi, Yoon-Jung,Lee, Seon-A,Kim, Hye-Kyeong 한국주거학회 2007 한국주거학회 논문집 Vol.18 No.5

        This is a case study for improving the sound environmental quality of cafeteria in university campus. The purpose of the study is to find out the present condition of physical level, type, and cause of indoor noise of cafeteria in university campus by comparison with a restaurant near campus. Research methods were field survey and questionnaire survey. Field survey was consisted of measurement on equivalent and instant noise level and observation on noise type. Respondents of questionnaire survey were 60 students using subject cafeteria or restaurant. Surveys were carried out in the 8th and in the 14th of December 2005. The results are as follows. 1) Indoor noise levels of the cafeteria were measured as $67.2{\sim}76.6$ (average 73.3) dB(A)Leq5min and $60.3{\sim}90.5$ (average 71.2) dB (A), exceeded the indoor noise recommended value of ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). But noise levels of the restaurant were $61.6{\sim}70.4$ (average 66.9) dB(A)Leq5min and $59.8{\sim}70.6$ (average 64.9) dB(A). 2) The users's responses on major noise type in the cafeteria were 'noise by handling equipment and tableware', 'noise by moving chairs', and 'talcing noise', but 'taking noise' and 'background music' in the restaurant. 3) It was found that indoor noise level of the cafeteria was caused by sound reflection of finishing materials, noise diffusion by open type kitchen, and dragging noise of movable furniture.

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