• 한국환경복원기술학회지
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• 제11권4호
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• pp.24-36
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• 2008

The essence of a natural stream restoration project is providing habitats for various creatures in terms of the stream's environmental function. This research suggests the problems of natural stream restoration project by studying streams in terms of habitats for creatures and reviewing the national and international cases on existing natural stream restoration project. As a solution for the above, this research suggests a preservation method for biotope of upper stream areas focusing on the fish biotope area considering the ecological characteristics and preservation value of the respective stream so that the stream can be preserved as habitats for creatures. The research was carried out on Cheonglimli Baekcheon region which is an upper stream area of Buan-Dam located in the public park in Byunsanbando, Buangoon, Jeonlabookdo. We suggest the preservation method based on the habitat environment and keystone species of fish. The habitat environment evaluation was carried out mainly being divided into three groups namely, habitats and surrounding environment, reservoir's features and fish way and the diversity of fish. By improving the problematic elements discovered through such evaluation, it tries to improve the biotope of the stream and continuously preserve the stream. In addition, in order to restore the stream as habitats for various creatures, this research suggests to select keystone species which are suitable for the stream environment and restore the habitats based on the keystone species rather than restoring habitats for all species. Fish not only plays the role of a consumer of Epilithic algae and water beetles but also plays an important ecological role as a food for birds or small mammalia. If such ecologically important biotope for fish is preserved, the ecological environment of the stream will be maintained more stably.

• 한국환경복원기술학회지
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• 제7권3호
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• pp.26-34
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• 2004

It is expected that the different techniques of stream restoration could be caused the different conditions of the stream ecosystem. The study was to investigate and compare plants and vegetation clusters of appearing plant species in the upper and lower section of the Seo-Ho stream, It was classified and listed all of the plants appeared in the upper and lower section of the stream, It was used the belt-transect method and Unweighted pair group method using arithmetic algorithm in order to examine and analyzed discover the vegetation clusters, In the result, 28 families and 114 species appeared in the upper section, In the other side, 26 families and 93 species appeared in the lower section of the steam. The naturalized index of the upper section was 21%, and that of the lower section was 27%. In addition, the upper section has more various geographical features than lower section of the stream. So that, consequently the study shows that the different techniques of stream restoration could be caused the different growth of the stream ecosystem.

• Ecology and Resilient Infrastructure
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• 제4권4호
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• pp.216-225
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• 2017

We assessed the microhabitat conditions of three fish species (black shinner Pseudopungtungia nigra, striped shinner Pungtungia herzi, Korean shinner Coreoleuciscus splendidus) considering various stream order in the Geumgang River Basin. A total of 1,275 individuals were collected from 19 sites. And the microhabitat condition was assessed measuring flow velocity, water depth and substrate size at each site. The highest relative frequencies for P. herzi, C. splendidus and P. nigra were calculated 100% (n = 310), 78.9% (n = 784) and 47.3% (n = 181) respectively. P. herzi appeared in all streams, irrespective of their stream order; however, appearance in streams with the $2^{nd}$ order or lower was found to be scarcer than in the ones with the $3^{rd}$ order or higher. On the other hand, P. nigra and C. splendidus didn't appear in streams with the $2^{nd}$ order or lower. When it comes to P. nigra, the ones with 7 to 8 cm in length most frequently appeared. They inhabited streams, mainly, with 0.2 to $0.4m\;s^{-1}$ and 0.5 m in velocity and water depth, respectively. The three species all preferred runs as types of habitats with lots of coarse gravels-cobbles. P. herzi, the ones with 5 cm or shorter in length most frequently appeared. They inhabited streams, mainly, with 0 to $0.3m\;s^{-1}$ and 0.4 m in velocity and water depth, respectively. C. splendidus with 7 to 8 cm in length occupied the majority of them. They appeared in streams, mainly, with $0.9m\;s^{-1}$or higher and 0.3 m in velocity and water depth.

• 한국환경과학회지
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• 제7권6호
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• pp.845-851
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• 1998

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under II class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream. The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제6권2호
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• pp.79-86
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• 1999

A Boolean function generates a binary sequence which is frequently used in a stream cipher. There are number of critical concepts which a Boolean function, as a key stream generator in a stream cipher, satisfies. These are nonlinearity, correlation immunity, balancedness, SAC (strictly avalanche criterion), PC (propagation criterion) and so on. In this paper we construct an algorithm for finding the correlation immune order of a Boolean function, and check how long to find the correlation immune order of a given Boolean function in our algorithm.

• 한국환경복원기술학회지
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• 제21권2호
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• pp.13-26
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• 2018

The restoration of the impaired stream ecosystem is an important part of river policies in Ministry of Environment (MoE). However, the diagnosing the impairment sources of stream ecosystem has been omitted on the current river projects and policies. This phenomena lead the remaining impairment sources keep influencing on negative effects on streams. Hence, it is critical to construct a diagnosis system of impairment sources in order to increase the efficiency of various river restoration projects and policies. Moreover, it is also important to understand the relative impact of socio-economic factors of the impairment of stream ecosystems so as to build a domestic diagnosis system in place. Therefore, the study aims to analyse the relative effects of socio-economic factors which are the source of the stream ecosystem impairments through implementing the Analytic Hierarchy Process (AHP). In order to achieve the goal, a list of socio-economic factors influencing the stream health has been derived. On the basis of the derived causes list, AHP questionnaire were carried out to the experts of aquatic ecology. The study results could be implemented to analysing the relative influence of socio-economic impairment causes in domestic stream environments. In addition, more case study investigation is needed to cross-check if the derived impairment causes and weights are applied in the field as well as to develop more reliable indicators.

• 한국지형학회지
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• 제25권2호
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• pp.1-14
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• 2018

The main objective of this paper is to classify properties of the locational environment for each debris type by calculating likelihood ratio based on the correlation between the distributions for each type of debris landform. A total of 8 thematic maps, like as elevation, slope, aspect, curvature, topographic wetness index (TWI), soil drainage, geology, and landcover including with GIS spatial information generally used in this type of debris landform analysis. The results of this study showed that the block stream had a high likelihood ratio compared to talus in areas with relatively high elevation; and concerning slope, the block stream had a high likelihood ratio in a relatively low region than talus. Concerning aspect, a clear correlation could not be analyzed for each debristype, and concerning curvature, the block stream displayed a developed slope on the more concave valley than the talus. Analysis concerning TWI, the block stream displayed a higher likelihood ratio in wider sections than talus, and concerning soil drainage, the talus and block stream both displayed a high likelihood ratio in regions with well-drained soil. The talus displayed a high likelihood ratio in the order of metamorphic rocks, sedimentary rocks, and granite, while the block stream displayed a high likelihood ratio in the order of volcanic rocks, granite, and sedimentary rocks. In addition, concerning landcover, the likelihood ratio had the most concentrated distributed compared to natural bare land only concerning talus. Based on the likelihood ratio result, it can be used as basic data for extracting the possible areas of distribution for each debris type through the GIS spatial integration method.

• 생태와환경
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• 제41권2호
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• pp.137-143
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• 2008

The abundance and community structure of epilithic diatoms grown on different substrata were investigated in two first-order streams located in a limestone and granite area, north of the Suzuka Mountains in Central Japan. Experiments were conducted as follows: limestone and granite without algae were submerged in their own streambed or another stream station and incubated for seven weeks, while limestone and granite with algae were transferred to another stream station and incubated at the same time. The diatom biomass was consistently high in the lime-stone station experiments compared to those at the granite station. In addition, there was more diatom biomass on granite substrata than on the limestone substrata at both stations. The present results suggested that the difference in water chemistry including the major nutrient concentrations was the limiting factor for algal growth in these two streams; however, when the water chemistry was the same in each stream, the difference in substratum characteristics became the important factor affecting the diatom abundance. The diatom community grown on the transferred substrata with and without algae became similar to those grown on the original substrata in each stream during the incubation period. It was suggested that the effect of the substrata characteristics on the diatom community structure was rather small.

• Nuclear Engineering and Technology
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• 제16권1호
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• pp.21-28
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• 1984

수치확산을 포함한 truncation오차의 줄임은 수치해석의 중요한 과제가 되어왔다. Stream line방법이 교차수치 확산과 비확산형의 truncation 오차를 제거하기 위하여 고안되었다. 또한, stream line방법과 유한 차분법이 합쳐진 2단계 stream line방법이 비압축성 난류유동의 지배 방정식을 풀기 위하여 고안되었다. 이 방법은 유한 차분법과 비교되었으며, 두 방법 모두 실험자료와 비교되었다. 그리고, 두 방법의 truncation 오차를 비교하기 위하여 truncation 오차 분석이 행해졌다

• 한국조경학회지
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• 제32권4호
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• pp.39-48
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• 2004

In the 1960s, polluted urban streams were covered and paved in concrete. Rivers became sewers buried under road. As a result, wildlife habitat was lost and the open stream space was gone. In the 1990s, there was a movement for restoring urban streams to enhance the quality of life of inhabitants. Chungkye Stream, whose covering began from early 1950s and ended in 1977, is now in the process of restoration together with the Central Business District (CBD) Redevelopment Plan. However, as the construction proceeds, several problems were raised, and serious controversies resulted. Therefore, this study aims to investigate the validity of the approach of the Chungkye Stream Restoration Project through a literature survey and a site survey, and to present the improved alternative. Ultimately, the study aims to contribute to present references or guidelines for similar urban stream restoration projects. The Chungkye Stream Restoration Project has some of the following problems. First, the construction should be done based on the long-term urban redevelopment plan. Second, the construction period should be extended to restore urban streams. Third, the cultural asset conservation plan should be implemented. In order to fulfill the anticipated purpose, the above mentioned problems need to be solved.