북한산국립공원의 계류수질 보전 전략(I)

박재현,우보명,김우룡,안현철,조현서,추갑철,김춘식,최형태,Park, Jae-Hyeon,Woo, Bo-Myeong,Kim, Oue-Ryong,Ahn, Hyun-Chul,Cho, Hyun-Seo,Choo, Gab-Chul,Kim, Choon-Sig,Choi, Hyung-Tae 한국환경복원기술학회 2001 한국환경복원기술학회지 Vol.4 No.3

This study was conducted to investigate physicochemical property changes from July 1998 to August 2001 in Mt. Bukhansan National Park. Four water sampling points were selected to measure the quality of stream water in the northeastern part of the Mt. Bukhansan National Park. The results were summarized as follows; In spring, the average pH of stream water was below the first class of the river water quality standard, while it was normal level in summer. The average electrical conductivity was about 2.3~3.3 times higher in downstream water than in upstream water during spring and summer. The contents of anions($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) were about 1.1~7.4 and 0.4~11.4 times higher in downstream than in upstream water, respectively. These results indicate that water quality was poorer in downstream than in upstream water. We suggest that stream water in the Mt. Bukhansan National Park should be protected from impacts of snow melting mineral particles in spring season and human impacts like wastewater of point source in summer season.

지리산국립공원내 칠선계곡 탐방로의 회복에 관한 분석

박재현 ( Jae Hyeon Park ) 한국환경보건기술학회(구 한국환경복원녹화기술학회) 2010 한국환경복원기술학회지 Vol.13 No.2

To investigate the restoration procedure on soil physical properties at the surface of visiting road affected by rest-year system. This study was carried out at visiting roads of stream of Chilsun in Jirisan. Mean soil strength in 20cm of soil depth was lower in the Rest-Year System areas (1.5-1.9 times in Site 2, 1.1-7.5 times in Site 3) than in the control (Site 1). Soil strength was recovered by the Rest-Year System in the national park. Mesopore rate (pF 2.7) in 0-15 cm of soil depth was higher in the Rest-Year System areas (1.2 times) than in the control. This indicates that mesopore rate is rapidly restoring in the Rest-Year System areas. Pore space rate in 0-7.5 cm of soil depth was higher in the Rest-Year System areas (23.2% in Site 2, 23.6% in Site 3) than in the control (22.4% in Site 1). Pore space rate in 7.5-15 cm of soil depth was also higher in the Rest-Year System areas (22.9% in Site 2 and Site 3) than in the control (18.9% in Site 1). Soil pore space was remediable by the Rest-Year System. Bulk density in 0-7.5 cm of soil depth was lower in the Rest-Year System areas (1.674g/cm3 in Site 2, 1.668g/cm3 in Site 3) than in the control (1.723g/cm3 in Site 1). Bulk density in 7.5-15 cm of soil depth was lower in the Rest-Year System areas (1.785g/cm3 in Site 2 and 1.721g/cm3 in Site 3) than in the control (1.721g/cm3 in Site 1). Soil bulk density was decreased in the Rest-Year System areas of the national park. Amount of soil erosion was lower in the Rest-Year System areas (0.017m3/km/yr in site 2, 0.023m3/km/yr in site 3) than in the control (0.054m3/km/yr in site 1).

일본(日本)에서 한류변(漢流邊)의 환경부원(環境復元) 발전전략(發展戰略)(I)

박재현,우보명,이헌호,Park, Jae-Hyeon,Woo, Bo-Myeong,Lee, Heon-Ho 한국환경복원기술학회 2000 한국환경복원기술학회지 Vol.3 No.1

This study was carried out to introduce current status and development strategy for an environmental restoration of stream side in Japan, and to consider a methodology which could be effectively applied for the environmental restoration of stream side in Korea. Since the end of 20th century, the native ecology and landscape of Japan remained only a limited areas such as stream side, water side and forest areas. Therefore, recently the works of forest conservation and erosion control of environmental restoration on stream side tended to increased. The strategic prospects of environmental restoration in Japan were summarized as follows : 1. From the ecological point of view, we have to develop a certain method and technology in construction of forest conservation and erosion control to prevent environmental problem from erosion control works. 2. We have to restore not only a continuity of stream side forest from a primitive area to an estuary but also the stream side forest to preserve and restore a stream side vegetation on a primitive watershed areas. 3. We have to improve a method of construction or removal of a structure which were constructed in the stream to restore a water side environment and an interaction system for an integration on a forest land, stream, and erosion control. Additionally, we have to establish an integrated evaluation method and an enforcement system after investigation of influences on natural environment, stream, and forest etc. 4. We have to conduct an integrated research to investigate the ecosystem of stream side, and construct environmentally friendly water park and erosion control park which considered natural environment and its landscape. Additionally, we need to introduce and adopt a natural style stream construction method to restore a water side areas.

북한산국립공원 북동사면에서 동결융해침식 및 토사유출이 계류수질에 미치는 영향

박재현(Jae Hyeon Park) 한국산림과학회 2001 한국산림과학회지 Vol.90 No.4

This study was conducted to investigate influences of solifluction and sediment runoff on the stream water qualities during the spring season. The study sites were four points in the northeastern area of the Bukhansan National Park. And, field surveys were carried out in the spring of 1999, 2000 and 2001. The results of this study were summarized as follows; During the investigation period, the amounts of sediment caused by solifluction on stream side slopes in the downstream were 1.3∼1.7 times as large as those in the upstream. The pH of sediment caused by solifluction was a potential influence on the pH of stream water. Amounts of dissolved Cl^-, NO₃^- and SO₄^(2-) in stream water were proportion to the average amounts of Cl^-, NO₃^- and SO₄^(2-) in the sediment caused by solifluction. In the spring, the average pH of stream water was lower than the first class of the river water quality standard because of increasing chemical concentration as well as the contents of anions(Cl^-, NO₃^- and SO₄^(2-)) in the spring season. Also, the average electrical conductivity of water in downstream was about 2.3-3.3 times higher than that in upstream. The amounts of anions(Cl^-, NO₃^- and SO₄^(2-)) of water in downstream were about 1.2∼7.4, 1.1∼3.9, 1.1∼1.4 times higher than those in upstream, respectively. Therefore, these results showed that the water quality of downstream was worse than that of upstream. As a result of regression analyses, the linear and exponential equation of pH and water quantity was pH = 1.7926 × stream water quantity + 5.9577(R² = 0.46), and those of electrical conductivity and water quantity was EC = 34.417e^(3.6334 × stream water quantity(m/sec) (R² = 0.44).

마르코프 랜덤필드를 이용한 무관리형 화상분할 알고리즘

박재현,Park, Jae-Hyeon 한국정보처리학회 2000 정보처리논문지 Vol.7 No.8

In this paper, a new unsupervised image segmentation algorithm is proposed. To model the contextual information presented in images, the characteristics of the Markov random fields (MRF) are utilized. Textured images are modeled as realizations of the stationary Gaussian MRF on a two-dimensional square lattice using the conditional autoregressive (CAR) equations with a second-order noncausal neighborhood. To detect boundaries, hypothesis tests over two masked areas are performed. Under the hypothesis, masked areas are assumed to belong to the same class of textures and CAR equation parameters are estimated in a minimum-mean-square-error (MMSE) sense. If the hypothesis is rejected, a measure of dissimilarity between two areas is accumulated on the rejected area. This approach produces potential edge maps. Using these maps, boundary detection can be performed, which resulting no micro edges. The performance of the proposed algorithm is evaluated by some experiments using real images as weB as synthetic ones. The experiments demonstrate that the proposed algorithm can produce satisfactorY segmentation without any a priori information. 본 논문에서는 새로운 무관리형 화상분할 알고리즘이 제안된다. 제안된 알고리즘은 화상에 내재되어 있는 구조 정보를 모델링하기 위하여 마르코프 랜덤필드의 특성을 이용하고 있다. 텍스쳐 화상은 정상상태의 가우스 마르코프 랜덤필드가 2차원의 격자구조 위에 실현된 상태로 간주되었으며 2차의 비순차근방을 갖는 조건부 자기회귀함수를 이용하여 모델링 되었다. 화상의 경계면 감출을 위하여 마스크로 선택된 두 영역에 대한 가설검정이 수행된다. 이 방법은 선택된 두 영역이 같은 종류의 텍스쳐라고 가정을 한 후 조건부 자기회귀모델의 매개변수를 최소평균제곱오차 측면에서 추정한다. 가설이 거절되면 두 영역의 상이함을 측정한 그 값이 선택된 영역에 누적된다. 이와 겉은 방법을 통하여 잠재적인 경제지도가 얻어지며, 이것을 통하여 여러 종류의 텍스쳐 화상의 분할이 미세오류경계 없이 이루어지게 된다. 제안된 알고리즘의 성능은 인공화상 뿐만 아니라 실제의 자연화상을 이용한 실험을 통하여 입증되었으며 일체의 사전정보 없이도 만족할 만한 결과를 보여 주었다.

가압유동층의 수력학적 특성 및 압력 변동

박재현,조성호,한근희,진경태,손재익 ( Jae Hyeon Park,Sung Ho Cho,Keun Hee Han,Gyoung Tae Jin,Jae Ek Son ) 한국화학공학회 1996 화학공학의이론과응용 Vol.2 No.2

홍수시 얕은기초의 세굴위험도 평가 사례연구

박재현,이주형,정문경,곽기석,Park. Jae-Hyun,Lee. Ju-Hyung,Chung. Moon-Kyung,Kwak. Ki-Seok 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1

Scour vulnerability evaluation for shallow foundations was performed to assure bridge safety against scour in the national capital region. The case studies for 26 shallow foundations consisted of site investigation including boring test, bridge scour analysis for the design flood, bearing capacity evaluation of the bridge foundation before and after scour, and comprehensive evaluation of bridge scour vulnerability. Bridge scour vulnerability was determined based on the interdisciplinary concept considering predicted scour depth for the design floods and bearing capacity of foundation as well as dimensions of foundation. Nine of 26 shallow foundations showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 were expected to maintain their stability against scour.

Homocysteine과 혈중(血中) 지질농도(脂質濃度)와의 상관성(相關性) 연구(硏究)

박재현,황우준,조남근,김성철,고영철,Park, Jae-Hyun,Hwang, Woo-Jun,Cho, Nam-Geun,Kim, Sung-Chul,Ko, Young-Chul 대한한방내과학회 2006 大韓韓方內科學會誌 Vol.27 No.3

Object : This study was carried out to investigate the correlation between homocysteine and serum lipids which are known risk factors of stroke. Methods : The subjects were a total of 60 patients divided into a control group (n =30) and a sample group (n =30). The control group was normal homocysteine level without clinical symptoms, and the sample group was high homocysteine level with headache, dizziness, hypertension and so on. clinical symptoms, Each group was measured and compared for serum homocysteine, total cholesterol, triglyceride(TG), low density lipoprotein(LDL), and high density lipoprotein(HDL). Results : Total cholesterol, TG, and LDL were significantly increased and HDL was significantly decreased in the sample group. which was a high homocysteine level group compared with the control group, which was a normal homocysteine level group. Conclusion : In these results. it was suggested that increase of homocysteine leads to increase of serum total cholesterol, TG, LDL, but causes decrease of HDL. It seemed that risk of stroke is more at high homocysteine level than normal.

복사효과를 고려한 기체-입자 직접접촉식 열교환기 해석

박재현,백승욱,권세진,Park, Jae-Hyeon,Baek, Seung-Uk,Gwan, Se-Jin 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.4

A direct contact heat exchanger using particle-suspended gas as a heat transfer medium is analyzed with an extended emphasis on the radiation, i. e., considering the radiation by both gas and particles. While the Runge-Kutta method is used for a numerical analysis of the momentum and energy equations, the finite volume method is utilized to solve the radiative transfer equation. Present study shows a notable effect by the gas radiation in addition to the particle radiation, especially when changing the chamber length as well as the gas and particle mass flow rate. When the gas and particle mass flow rate is raised, the gas temperature in the particle heater still increases as the gas absorption coefficient increases, which is different from the results for the small scale heat exchanger.

의과대학/의학전문대학원 학생들의 학습에 대한 신념

박재현,Park, Jaehyun 연세대학교 의과대학 2012 의학교육논단 Vol.14 No.2

Learning in medical school is usually regarded as a very specialized type of learning compared to that of other academic disciplines. Medical students might have general beliefs about their own learning. Beliefs about learning have a critical effect on learning behavior. There are several factors that affect medical students' learning behavior: epistemological beliefs, learning styles, learning strategies, and learning beliefs. Several studies have addressed epistemological beliefs, learning styles, and learning strategies in medical education. There are, however, few studies that have reported on medical students' beliefs about learning. The purpose of this study was to determine what learning beliefs medical students have, what the causes of these beliefs are, and how medical educators teach students who have such beliefs. In this study, the five learning beliefs are assumed and we considered how these beliefs can affect students' learning behaviors. They include: 1) medical students are expected to learn a large amount of information in a short time. 2) memorization is more important than understanding to survive in medical schools. 3) learning is a competition and work is independent, rather than collaborative. 4) reading textbooks is a heavy burden in medical education. 5) the most effective teaching and learning method is the lecture. These learning beliefs might be the results of various hidden curricula, shared experiences of the former and the present students as a group, and personal experience. Some learning beliefs may negatively affect students' learning. In conclusion, the implications of medical students' learning beliefs are significant and indicate that students and educators can benefit from opportunities that make students' beliefs about learning more conscious.