• 한국지능시스템학회논문지
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• 제13권6호
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• pp.635-642
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• 2003

강화학습은 제어, 스케쥴링 등 많은 응용분야에서 성공적인 학습 결과를 얻었다. 기본적인 강화학습 알고리즘인 Q-Learning, TD(λ), SARSA 등의 학습 속도의 개선과 기억장소 등의 문제를 해결하기 위해서 여러 함수 근사방법(function approximation methods)이 연구되었다. 대부분의 함수 근사 방법들은 가정을 통하여 강화학습의 일부 특성을 제거하고 사전지식과 사전처리가 필요하다. 예로 Fuzzy Q-Learning은 퍼지 변수를 정의하기 위한 사전 처리가 필요하고, 국소 최소 자승법은 훈련 예제집합을 이용한다. 본 논문에서는 온-라인 퍼지 클러스터링을 이용한 함수 근사 방법인 Fuzzy Q-Map을 제안하다. Fuzzy Q-Map은 사전 지식이 최소한으로 주어진 환경에서, 온라인으로 주어지는 상태를 거리에 따른 소속도(membership degree)를 이용하여 분류하고 행동을 예측한다. Fuzzy Q-Map과 다른 함수 근사 방법인 CMAC와 LWR을 마운틴 카 문제에 적용하여 실험 한 결과 Fuzzy Q-Map은 훈련예제를 사용하지 않는 CMAC보다는 빠르게 최고 예측율에 도달하였고, 훈련 예제를 사용한 LWR보다는 낮은 예측율을 보였다.

• Journal of Korean Neurosurgical Society
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• 제61권6호
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• pp.761-766
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• 2018

Objective : Chronic subdural hematoma (CSDH) is a rare complication of unruptured intracranial aneurysm (UIA) clipping surgery. To prevent postoperative CSDH by reducing subdural fluid collection, we applied the modified arachnoid plasty (MAP) during the UIA clipping surgery to seal the dissected arachnoid plane. Methods : This retrospective study included 286 patients enrolled from July 2012 to May 2015. We performed arachnoid plasty in all patients, with MAP used after June 17, 2014. Patients were divided into two groups (non-MAP vs. MAP), and by using uni- and multivariate analyses, baseline characteristics, and relationships with postoperative CSDH between the two groups were analyzed. The degree of preoperative brain atrophy was estimated using the bicaudate ratio (BCR) index. Results : Ten patients (3.5%) among 286 patients had postoperative CSDH after clipping. Nine (3.1%) were in the non-MAP group, and one (0.9%) was in the MAP group. The higher BCR index showed statistical significance with occurrence of postoperative CSDH in both uni- (p=0.018) and multivariate (p=0.012; odds ratio [OR], 8.547; 95% confidence interval [CI], 1.616-45.455) analyses. MAP was associated with a lower risk of postoperative CSDH (p=0.022; OR, 0.068; 95% CI, 0.007-0.683). Conclusion : This study shows that the degree of preoperative brain atrophy is associated with an increased occurrence of CSDH after clipping and that MAP could help reduce the risk of postoperative CSDH after unruptured aneurysm clipping via a lateral supraorbital approach.

• 대한수학회보
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• 제35권3호
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• pp.533-545
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• 1998

In this paper, we prove the existence of solutions of the heat equation for harmonic map on a compact manifold with a boundary when the target manifold is allowed to have positively curved parts.

• 방송공학회논문지
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• 제17권3호
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• pp.459-470
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• 2012

본 논문은 영상 보간법을 이용하여 저해상도 깊이맵을 고해상도 깊이맵으로 변환하는 방법을 제안한다. 현재의 카메라 센서는 고해상도 색상 영상을 제공하는데 반해, 깊이 측정 장치는 저해상도의 깊이맵을 주로 제공한다. 본 논문은 기존의 양선형 보간법, 고등차수 보간법, 양측 보간법을 바탕으로 깊이맵에서 추출한 고주파 성분을 적용하여 깊이맵의 선명도를 증가한다. 이를 위해, 제안 방법은 고주파 성분 추출 단계, 고주파 성분 적용 단계, 및 영상 보간 단계를 거친다. 실험에서는 다양한 깊이맵 데이터에 제안 방법을 적용하였는데, 성능검증 방법으로 선명도(sharpness degree)와 블러 메트릭 (blur metric)의 두 객관적 측정을 통해서 제안 방법이 기존 방법에 비해 선명도가 약 2배 정도 증가했음을 보여준다. 또한 블러 메트릭은 평균 14%가 감소되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.87-92
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• 2002

Engineering geological studies were conducted for igneous rocks in southeast Korean peninsula. The purpose of the study is to establish zoning in view of engineering geology in ground construction. For engineering geological implication, lithology, lineament structure and discontinuities were surveyed and analysed. Using constructed data, We compared geological and engineering geological characteristics and made out the detailed engineering geological map. The map responses engineering characteristics such as weathering degrees, discontinuity systems of different rock types.

• The Korean Journal of Ecology
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• 제26권1호
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• pp.19-22
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• 2003

군락분류학에 기초한 현존식생도를 이용하여 토지에 대한 생태적 안전성 또는 위약성을 평가하는 '잠재인간간섭도' 평가기법을 개발하였다. 4개 범주(삼림지역, 개방수역-호소와 하천, 경작지 면적, 주택-도시화의 인공 면적)에 따라 입지도에 대한 직접평가 및 간접평가로부터 격자법과 등고선법에 의한 '잠재인간간섭도(潛在人間干涉圖)를 제작하였다. 이것을 토대로 토지의 훼손 잠재성을 평가하는 '교란핵구역'과 '위약(危弱)세포구역'을 규정하고, 토지 관리를 위한 생태적 접근을 시도하였다. 사례연구로 973개의 격자(500 m×500 m)로 이루어진 부산광역시 기장군 일대의 현존식생도 상에서 이루어졌다. 사례연구 지역 내에서 '교란핵구역'은 51군데이며 '위약세포구역'은 28군데로써 대상 면적의 약 8.1%를 차지하는 것으로 나타났다. 식생학적 현존식 생도를 이용한 '교란핵구역'과 '위약세포구역'을 발굴하는 잠재인간간섭도는 토지 이용과 보존에 관한 생태학적 전략 구축에 있어서 구체적인 현장적 입지진단 정보를 제공하는 유효수단인 것으로 밝혀졌다.

• 로봇학회논문지
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• 제6권1호
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• pp.42-48
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• 2011

It is very important for a mobile robot to recognize and model its environments for navigation. However, the grid map constructed by sonar sensors cannot accurately represent the environment, especially the narrow environment, due to the angular uncertainty of sonar data. Therefore, we propose a map building scheme which combines sonar sensors and IR sensors. The maps built by sonar sensors and IR sensors are combined with different weights which are determined by the degree of translational and rotational motion of a robot. To increase the effectiveness of sensor fusion, we also propose optimal sensor arrangement through various experiments. The experimental results show that the proposed method can represent the environment such as narrow corridor and open door more accurately than conventional sonar sensor-based map building methods.

• 한국환경복원기술학회지
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• 제15권2호
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• pp.31-40
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• 2012

The Environmental Conservation Value Assessment Map (ECVAM) is a five grade assessment map created with nationally integrated environmental information and environmental values. The map is made through the evaluation of 65 items, including greenbelt area and naturalness. Naturalness means original state of nature, and it is one of the most important evaluation items for conserving nature. The criteria of naturalness includes the Degree of Green Naturality (DGN) made by MOE. Using the data which has been not updated is a problem of accuracy for ECVAM. Therefore, this study would like to improve the criteria of naturalness. To improve the criteria, the study examined the effectiveness of DGN using field survey. The results of analysis the naturalness without DGN, some area changed grade of naturalness have been already damaged or cleared for agriculture and industrial purposes. The grade of naturalness should be included the concept of vegetation transition like DGN. The study suggested a improved method using vegetation type (natural and planted forest), forest age, and the grade of vegetation conservation. The method was reviewed by experts and field survey. After applying the method in South Korea, the grade of naturalness were distributed evenly like GradeI is 38.87%, GradeII is 37.62%, GradeIII is 23.51%, respectively. From the results of field survey, over 4 grade of forest age in natural forest showed similar pattern of structure and composition in original forests. Therefore, the improved criteria explained the naturalness better than existing criteria, and the accuracy of ECVAM has been improved more.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 1998년도 추계학술대회 발표요약문
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• pp.34-36
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• 1998

In Korea, the initial installation of GIS requires lots of cost, time, and human efforts, If the accuracy of GIS data does not meet the certain standard for use, the system may not work as expected. So, it needs to be investigated for the accuracy of raw data. However, there is little study for the accuracy of raw data in Korea. Therefore, the purpose of this study is to review the data accuracy of raw data - geologic map, 1:5,000 and 1:25,000 scale topographic map, forest stand map, degree of green naturality(DGN) map, and detailed survey data of DGN map - for fulfilling the expected use in Korea. After this study, some errors in data were surveyed and following conclusions were derived. (1) There is a lack of data, e. g, wildlife habitat map. (2) Some data are misinterpreted depending on the location in the geologic map. (3) Some data are not updated after change of topography in the topographic map. (4) Some data are not edited properly in the forest stand map. (4) DGN classification system does not reflect the characteristic of Korean vegetation community. So, it needs to be refined and restructured.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1129-1133
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• 2007

Assessment of noise exposed population is a method for checking the degree of environmental noise and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise reduction policy and action plan by accurately assessing the area that noise causes harm to human health. Recently, a noise map, which can predict noise in comprehensive areas, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for the noise can be considered more effectively by using assessment methods of noise exposed population for specific noise levels, areas, and building types which are the main input factors in noise maps. In this study, Assessment methods of noise exposed population by using 2D noise map are compared with those by 3D noise map.