• 생태와환경
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• 제40권1호
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• pp.163-172
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• 2007

본 연구에서, 금강의 작은 지류 하천들인 31개 소하천들을 대상으로 2003년 10월부터 11월까지 어류상, 군집분석 및 하천 형태에 대한 연구를 수행하혔다. 조사된 소하천들은 하폭, 수심, 하상 구성물질, 하천식생 및 주변의 토지 이용도에 따라 산지형, 산지-평지형, 평지형, 농수로형소하천의 4가지 유형으로 구분 대별되었다. 조사기간 중 서식이 확인된 어류는 4과 8종이었으며, 잉어과 어류가 다른 분류군에 비해 가장 높게 나타났고, Rhynchocypris oxycephalus가 419개체로 전체의 73%로 우점종으로 나타났다. R. oxycephalus는 100%산림지역과 연계된 지역이면서 점오염원 및 비점오염원이 전혀 없는 5개의 모든 산지형 소하천(SM)에서 출현한 유일한 종으로 나타났다. 또한, 본 조사대상 소하천들에서 출현한 종들 중R. oxycephalus의 출현비율은 하천의 하상구성 인자 중 모래 (Sand, Sa)와 작은 자갈(Pebble, Pe)로 구성된 하천들 보다 암반(Bedrock, Be)과 큰돌(Boulder, Bo)로 이루어진 하천들에서 양의 상관관계를 갖는 것으로 나타났다(r=0.754, p<0.001, n=31). 2007견 환경부에서 공표한 생물학적 수질기준안에 의거할 때 본 산지형 소하천(SM)지역은 "최적상태"로 나타났다. 이와 같은 결과는 국내 하천들의 최상류역에 서식하는 것으로 알려진 종들의 일반적인 경향과 일치하는 것으로 사료되었다. 유형별로 산지형 소하천(SM)에서 R. oxycephalus 1과 1종, 산지-평지형 소하천(MF)에서 R. oxycephalus등 4과 6종, 평지형 소하천 (FL)에서 R. oxycephalus 등 4과 8종, 농수로형 소하천(AW)에서 R. oxycephalus등 2과 2종의 서식이 확인되었다. 본 연구 결과에 따르면, 오염원이 전혀 없고, 산림으로 둘러 쌓인 하천에서 출현한 R. oxycephalus는 생물학적 수질판정시 1급수 지역에서 최대 값을 보이는 생태지표종 중의 하나로서 사료되었다.

• 한국환경생태학회지
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• 제20권4호
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• pp.415-424
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• 2006

산림유역 조건에 따른 붕괴 토사량을 측정하여 사면 붕괴가능성을 평가하고 붕괴위험 지역에 대한 예지기술(豫知技術)을 개발함으로서 산지사면에서 발생하는 각종 재해에 대한 피해를 최소화 할 수 있는 산림유역 관리에 대한 기술적 기초 자료를 제공하고자 연구하였다. 붕괴 위험지역을 평가한 결과 I급지(매우 위험지역)는 화성암지 역으로 침엽수림이며 임령은 20년생 이하, 토심은 30cm 이하, 토성은 사질식양토(SCL), 석력함량은 $31{\sim}40%$, 사면방위는 남${\sim}$동$(S{\sim}E)$사면, 주하천길이는 $2,501{\sim}3,500m$, 총하천수는$26{\sim}30$개, 총하천길이는$5,501{\sim}10,000m$, 하천차수는 3차수, 일차하천수는 $11{\sim}15$개 또는 16개 이상, 사면경사는 $31^{\circ}$이상의 지역으로 평가되었고, II급지(위험지역)는 변성암지역으로 활엽수림이며 임령은 $21{\sim}24$년생, 토심은$31{\sim}40cm$, 토성은 미사질식양토(SiCL) 또는 사질식양토(SCL), 석력함량은 $11{\sim}20%$, 사면방위는 남${\sim}$서$(S{\sim}W)$사면, 주하천길이는 $1,501{\sim}2,500m$, 총하천수는 $6{\sim}10$개, 총하천길이는 $3,501{\sim}5,500m$, 하천차수는 2차수, 일차하천수는 $6{\sim}10$개, 사면경사는 $31^{\circ}$이상의 지역으로 평가되었으며, III급지(비 위험지역)는 퇴적암지역으로 임상은 혼효림, 임령은 25년생 이상, 토심은 $41{\sim}50cm$, 토성은 미사질식양토(SiCL), 석 력함량은 10% 이하, 사면방위는북${\sim}$서$(N{\sim}W)$사면, 주하천길이는 500m 이하, 총하천수는 5개 이하, 총하천길이는 1,000m 이하, 하천차수는 1차수, 일차하천수는 2개 이하, 사면경사는 $25^{\circ}$이하의 지역으로 평가되었다. 붕괴위험 예측치를 이용하여 붕괴위험지역을 예지한 결과 점수의 합계가 I급지는 4.8052점 이상이며 II급지는 4.8051점에서 2.5602점 사이에 해당하며 III급지는 2.5601점 이하의 지역으로 분석되었다.

• 보건행정학회지
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• 제19권3호
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• pp.142-165
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• 2009

Although providing universal coverage for health care through the National Health Insurance(NHI) is a remarkable achievement, the issue of limited benefit coverage of the NHI has been at the core of national debate over how to improve its coverage. This study aims to evaluate benefit extension strategies and implemented policies with regard to the NHI since 1989 using 'policy window theory' proposed by John W. Kingdon. Understanding problem stream, policy stream, political stream, and coupling streams regarding the NHI, in particular benefit extension, would contribute to broaden policy debates and to develop more effective strategies for the future. Historically, political stream had opened policy window in the past two decades and policy streams can be characterized by three waves. Three streams have been coupled since 2003 and the government had a strong will to fulfill better performance of NHI coverage. Study findings indicate that identification of problem structure regarding NHI benefit was not connected with policy stream tightly. In addition, there has been limited discussion on policy goal and principles for extension coverage of the NHI. Policy strategies to improve coverage of the NHI should be linked to characteristics of problem and sought solutions under the principle which is expected to be sustainable through consensus in the society.

• 한국환경복원기술학회지
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• 제20권1호
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• pp.55-75
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• 2017

The purpose of this study is to present the basic data for restoration of physical stream environment by analyzing habitat variables because habitat environment is changed due to the construction of waterfront space in urban streams. Assessment results of 10 habitat variables(three divisions) were almost same as optimal condition, in the reach of reference stream where there are no stream crossing structures and channel alteration. Assessment results of reaches in urban rivers, where streams were improved on water-friendly recreation activities, appeared to be marginal condition. Because habitat environment got worse due to stream improvement works such as construction of weir for water landscape, stepping stones for walking, low water revetment and high water revetment, and high water channel. In addition, in the case of mid gradient stream, the frequency of riffles was small or not existed because the intervals of the river crossing structures was short. In the case of mild stream types, the diversity of the pool was damaged due to the deposition of sludge in the upstream pool of weir and the installation of low water revetment.

• 한국환경교육학회지:환경교육
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• 제24권2호
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• pp.1-20
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• 2011

The purpose of this research is to apply and evaluate the Water Environmental Education Program Using Streams(WEES) to pre-service teachers. WEES is developed to help the teachers increase their professionalism of incorporating a local environment into their inquiry teaching. The subjects of the study include the juniors of the Environmental Education Major at the Korea National University of Education. For the purpose this study, educational criticism about WEES was performed. The subject students were observed throughout the program application, after which a survey and in-depth interviews were carried out. As a result, the implementation elements and content organization of the WEES were found to be implemented in the application process in a satisfying level. In the content organization of the program, the preliminary preparation, visual assessment, and inquiry planning were organically connected with each other for inquiry purposes. The Intrinsic value of environmental education was also demonstrated in the implementation elements and content organization. Overall, the stream turned out to have a great value of environmental education and a potential as a place and material for environmental education. The great significance of the study can be found in that WEES took into account not only the characteristics of the ENVISION based on the watershed concept, but also the situations of Korea's environmental education and exploration from the perspective of environmental studies.

• 한국환경과학회지
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• 제7권1호
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• pp.112-115
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• 1998

During the spring and fall of 1994 and winter of 1995, the exposure time of periphyton biomass on terval. In the streams with low periphyton biomass (chi. a: 2-4 mg/$m^2$) in natural rocks, biomass of arttificial substrata (unglazed tile: $3.7{\times}9.5{\times}2 cm$) exceeded that of the natural rocks after 28 days, while sites with high biomass (chi. a: 20-60 mg/$m^2$) in natural rocks showed slower biomass accumulation after 40 days. Due to the high licht input and temperature in a Partially shaded mountain stream, development of periphyton biomass in spring occurred faster than that of winter. In general, development of periphyton biomass placed on artificial substrata took 4-5 weeks in spring and at least 6 weeks In winter to reach the natural level.

• 방송공학회논문지
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• 제7권3호
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• pp.271-276
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• 2002

디지털 방송 시스템 구축에 있어서 시스템 출력단의 기저대역 신호와 RF 신호가 포함하고 있는 MPEG-2 TS(Transport stream) 영역의 데이터를 분석하는 것은 시스템 경로상의 오류 유무와 그 위치를 파악하거나 유추하는데 중요한 자료를 제공한다. 송출되는 스트림은 RF(Radio frequency) 영역과 TS 영역에서 각각 여러 종류의 오류를 포함할 수 있으며, 이러한 오류를 정정하는 것은 셋톱 박스와의 정합, 안정된 수신성능 보장, 그리고 시청자 편의 등의 측면에서 매우 주요하다. 본 논문에서는 2001년부터 시작되어 현재 관악산에서 송출되고 있는 국내 지상파 디지털 TV(DTV, ATSC) 5개 채널중 지상파 방송 3사의 채널을 선택하여 이 채널의 MPEG TS 스트림상에서의 오류, PSIP(Program and System Information Protocol) 상에서의 오류, RF 영역에서의 오류 등 DTV 시스템에서 발생 가능한 오류들을 2001년 12월부터 2달 동안 측정하고 분석하였으며, 미국에서 측정한 RF 및 TS 스트림의 측정 및 분석 결과와 비교하였다.

• 환경영향평가
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• 제12권4호
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• pp.259-270
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• 2003

To investigate the water quality and the pollution state of lower Yeongsan river system, 38 water samples were taken from the main stream of the Yeongsan river, Gomakwon and Hampyeong streams of the system in dry and flood seasons, May and August, 2001. The Yeongsan river is typically natural in accordance with pH-& diagram. But the chemistry based on Piper's diagram indicates that the river is influenced by seawater. BOD increases as the sampling sites are approaching the downstream in Gomakwon and Hampyeong streams overwhelming WQS V grade of 12.40mg/l. T-N and T-P of the river are mainly loaded not in above branch streams but in the main stream of the river, which are caused by manure for farming, domestic animal discharges and life-sewage, in possible. Meanwhile, heavy metal contents are below WQS or not detect in whole water samples. So, it shows that the above river waters be polluted by not industrial but life/agricultural foul waters.

• Environmental Engineering Research
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• 제16권2호
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• pp.69-79
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• 2011

Rapid population growth and land use changes have severely degraded streams across the United States. In response, there has been a surge in the number of stream restoration projects, including stream restoration for mitigation purposes. Currently, most projects do not include evaluation and monitoring, which are critical in the success of stream restoration projects. The goal of this study is to review the current status of assessment methodologies and restoration approaches for streams in Virginia, with the aim of assisting the restoration community in making sound decisions. As part of the study, stream restoration projects data from a project in Fairfax County, Virginia was assessed. This review revealed that the stream assessment methodologies currently applied to restoration are visuallybased and do not include biological data collection and/or a method to incorporate watershed information. It was found from the case study that out of the twenty nine restoration projects that had occurred between 1995 and 2003 in Fairfax County, nineteen projects reported bank stabilization as a goal or the only goal, indicating an emphasis on a single physical component rather than on the overall ecological integrity of streams. It also turned out that only seven projects conducted any level of monitoring as part of the restoration, confirming the lack of evaluation and monitoring. However, Fairfax County has recently improved its stream restoration practices by developing and incorporating watershed management plans. This now provides one of the better cases that might be looked upon by stakeholders when planning future stream restoration projects.

• Journal of Computing Science and Engineering
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• 제5권4호
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• pp.294-304
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• 2011

Enhancing continuous queries over data streams with temporal functions and predicates enriches the expressive power of those queries. While traditional continuous queries retrieve only the values of attributes, temporal continuous queries retrieve the valid time intervals of those values as well. Correctly evaluating such queries requires the coalescing of adjacent timestamps for value-equivalent tuples prior to evaluating temporal functions and predicates. For many stream applications, the available computing resources may be too limited to produce exact query results. These limitations are commonly addressed through load shedding and produce approximated query results. There have been many load shedding mechanisms proposed so far, but for temporal continuous queries, the presence of coalescing makes theses existing methods unsuitable. In this paper, we propose a new accuracy metric and load shedding algorithm that are suitable for temporal query processing when memory is insufficient. The accuracy metric uses a combination of the Jaccard coefficient to measure the accuracy of attribute values and $\mathcal{PQI}$ interval orders to measure the accuracy of the valid time intervals in the approximate query result. The algorithm employs a greedy strategy combining two objectives reflecting the two accuracy metrics (i.e., value and interval). In the performance study, the proposed greedy algorithm outperforms a conventional random load shedding algorithm by up to an order of magnitude in its achieved accuracy.