• Title/Summary/Keyword: Change of stream shape

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An Analysis of the Runoff Variation due to Urbanization in Cho-kyung Stream Watershed (조경천 유역의 도시화에 따른 유출 변화 추이 분석)

  • Choi, Jung-Hwa;Lee, Jeong-Ju;Kwon, Hyun-Han
    • Journal of Wetlands Research
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    • v.11 no.3
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    • pp.161-169
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    • 2009
  • Rainfall-runoff procedures of urban area are more complicated than agricultural procedures. Extension and development of town leads to shift of the basin characteristics and it makes more difficult to use runoff models. In this study, the changes of hydrologic circumstances and the shape of hydrograph due to the urbanization in Cho-kyung river basin has been assessed which is the representative urban stream in Jeonju city. The urbanization can be classified as four typical year. The natural basin period(1924) that is before the urban development, the period of construction of Chonbuk National University campus (1963), the period of construction of residential area(1986), and urbanization process has been finally completed in 1995. The rainfall-runoff analysis has been carried out by Storm Water Management Model(SWMM) under condition of the basin characteristics and impervious area of each period. It was found that hydrologic characteristics such as river length, roughness coefficient, and coefficient of surface storage has been decreased. According to the land use change, the pervious area was decreased from 97.7% to 42%, while the impervious area was increased from 0.6% to 34%. The time of concentration was shorten from 90 minutes to 37 minutes. Along with decreasing the time of concentration, the peak discharge was increased from $4.37m^3/s$ to $111.13m^3/s$, and the runoff rate was also increased from 0.8% to 68%.

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Measurement of the Laminar Boundary Layer in a Streamwise Corner by using PIV Technique (PIV 기법을 이용한 Streamwise Corner 층류 경계층 측정 연구)

  • Park, Dong-Hun;Park, Seung-O;Kwon, Ki-Jung;Shim, Ho-Joon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.12
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    • pp.1165-1172
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    • 2009
  • The laminar boundary layer along a streamwise corner formed by two flat plates intersecting at right angle is measured by using Particle Image Velocimetry(PIV) technique. The free stream velocity ranges from 2.96m/s to 3.0m/s. The angle of incidence of the corner is set to 1.2 degree providing slightly favourable pressure gradient to ensure a laminar flow in the corner region. A round shape leading edge is used and the length of the model is about 1000mm. In the bisector plane, the measurement data show separation type velocity profiles having an inflection point which is a typical characteristic of laminar corner boundary layers. As the distance away from the bisector plane increases, velocity profiles are found to change into the Blasius profile. The change completes around half length of the boundary layer thickness in the bisector plane away from the bisector plane along the plate. In the bisector plane, the growth characteristic of the boundary layer thickness and the approximate similarity of velocity profiles are confirmed from the measurement data.

An Experimental Study to Estimate the Energy Change by Side Weir (횡월류위어에 의한 에너지변화 평가를 위한 실험연구)

  • Cho, Hong Je;Yoon, Yeong Bae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1B
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    • pp.57-62
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    • 2011
  • The river disaster caused by installation of hydraulic structures on the river gives varieties to flowing water stream, tractive force and so on. In this study, the changes of tractive force and energy from the side weir installation for the purpose of flood control was analyzed through laboratory experiment. The experiments of the pre and after-installation have been performed under conditions that waterway is trapezoidal shape, waterway slope ranges are from 0.1 to 1.0 percentage, and flow rates are 25 l/sec. As results, the specific energy ratio increases in the higher slope and at a certain point, larger specific energy ratio showed than 1 in the 1.0% slope. The tractive force ratio decreases in higher slope and the sections that tractive force ratio appeared higher than 1 are more widespread in the direction of downstream. And calculated tractive force is about 1.3.

A Study on Transition Process of Hanbyokdang by Diachronic Analysis (통시적 관점에서 본 한벽당(寒碧堂)의 변천과정)

  • Rho, Jae-Hyun;Shin, Sang-Sup
    • Journal of the Korean Institute of Landscape Architecture
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    • v.35 no.6
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    • pp.97-109
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    • 2008
  • This study first attempted to catch the transformational affairs and motives of the representative pavilion, Hanbyeok in Honam after its construction. Especially, it re-illuminated the morphologic, significant and functional change process of a pavilion after the early Joseon Dynasty by taking the local scenery, Hanbyeokdang as a sample, and considering the space and scenic characteristics, and diachronically understood its creation process and rebuilt its inherent positional meaning to reach the following conclusion. 1. Weoldanglu, at its early foundation, seems to have stressed the function of a private banquet and lecture hall to train younger students, and served as a reception space. Then the reception function gradually increased, and up to before 1530, it seems to have been called Weoldanglu(月塘樓) or Weoldangwon(月塘院). 2. In 1619, Governor Yoo Saek changed the pavilion name to Hanbyeokdang through the subject of a poem. 200 years after Weoldang's death, it became a public space called Hanbyeokdang, an amusement place in which scholars cultivated great morale, and participated in the sending-off and welcoming of predecessors and successors. This seems to have taken a foothold as a public event or entertainment space for the local administration, Jeonjuboo(全州府) through the remodeling process sponsored by the public. 3. Scenic language such as its indicating name, expression type and surrounding view through old map and so on, the shape of Hanbyeokdang evolved and changed to diverse types after the foundation of Weoldanglu, at the heart of which Hanbyeokdang with its two legs standing at a rock was located. 4. During the late 18th century, Hanbyeokdang seems to have been a wing corridor connected closely to the left corridor of the Jeonju stream bed, whose pattern is presumed to have existed even during the early 19308. Such changes in scenic language make us assume that diverse auxiliary space, a wing corridor, was erected for use as a public banquet and amusement spot of Jeonjuboo Castle, the inherent function of Hanbyeokdang after the mid 18th century. 5. Penetration of Hanbyeokgool and the erection of Hanbyeokgyo caused the change of the ancient shape of Hanbyeokdang. Specifically, a great Hanbyeokgyo passing by the pavilion changed the relative scale, so the pavilion image of pursuing unity with nature has lost the old inherent refinement and visual character.

Studies on Piroplasmosis Infection and Morphological Development of Piroplasma in Experimental Animals (피로풀라스마병(病)에 관(關)한 연구(硏究) 실험동물(實驗動物)에 대(對)한 감염시험(感染試驗) 및 그 형태학적(形態學的) 변화(變化)에 대(對)하여)

  • Han, T.W.
    • Korean Journal of Veterinary Research
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    • v.8 no.2
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    • pp.98-109
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    • 1968
  • The small type piroplasma which is known to be prevailing in Korean cattle was injected to un-susceptible hosts such as mice, guinea pigs, rats, rabbits, fowls and developing chicken eggs by i.v., i.p, and intra C.A.M. routes, and its morphological development in each animal species was observed. 1. The small type piroplasma of cattle did not produce any pathogenicity in the experimental animals such as mice, guinea pigs, rats, rabbits, fowls and developing chicken embryos. However, only a partial sign for developing cycle of the organism was observed in the peritoneal fluid. The schizogony of protozoa was not detected in any organs of the inoculated animals. 2. In the animals inoculated, the parasites of I-III types, relative to the process of time in the host, have changed their shapes into IV-VI types and then VI-X types however, the type X was not restored to the type I. In guinea pigs, more grape type was detected then X type in number, and in process of time, the shape was changed from round to elliptic, and the pointed end of the organism appeared in flesh color. 3. None of the organisms were found from the blood stream of inoculated animals excepts only a few piroplasma as were found in the experimental mice shortly after inoculation or i.v. route, No protozoa was also found in the organs of the animals autopsied. 4. The form change of protozoa was more clear in these animals than that in susceptible host. The most piroplasmas have changed their forms into VI-X types 30 hours after inoculation and were dispersed from R.B.C. Tracing of piroplasrna beyond this stage was not attempted. 5. The small type piroplasma comprises in I. X types and it is further believed that VII-X types which were freed from one cell proceeded to invade others. The from of development resembles to the small type of piroplasma which is prevailing in Japan.

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The Landscape Characteristics of Village Located in the Meander cut-off Area;The Case of Samji Village (곡류단절지에 입지한 마을의 경관특성;삼지마을을 사례로)

  • 임의제;최기수
    • Journal of the Korean Institute of Landscape Architecture
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    • v.28 no.2
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    • pp.109-109
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    • 2000
  • This study seeks what kind of factors influence to locate dwellings and to establish scenic spots in nature by a case study focused on a meandering stream. The study specially concentrates on the interrelationship between both residences and beautiful sceneries and a meander cut-off-area that reveals a special topographical characteristics, located at Samji village in Youngyang-eup, Youngyang-gun, Koungsangbuk-do. The meander cut-off area, developed at the middle or upper reaches of a river, often makes up specific landscapes such as precipitous cliffs, sheer cliffs and caves. And the area where is specially created by sudden change of flow due to erosion perceived by the cut surface to be the most beautiful scenic spot. These beautiful landscapes were used to be called as Dae, Dam or Gul and managed by Confucian scholars who enjoy refined taste and devote themselves to the study in nature. Moreover, the Ku-Hado-literary means the area of ex-flow-made the scholars' lving with a well prepared basis for agriculture where supplied a cornucopia of organic matters and water. The merit of agriculture made it possible that the scholars became economically independent, and the fact might be the essential point why the meander cut-off area took noticed. Actually, Cho-family has been in Smaji Village for generations, producing a large number of scholars and keeping the actual power of the region. The physical shape of the meander cut-off area, cozily surrounded by mountains, is considered as a good place for the dwelling due to the influence of traditional sight of view for location and P'ungsuchiri which is known as Feng Shui in China and geomancy in the western world. It is a fruit in it own way that we could find the ancestors' discernment and wisdom from this study, who have lived their lives adapting themselves to the given natural environment and also utilizing the nature wisely. But this is a current-argued study on the meander cut-off area. Follow-up studies have to be continued about the landscapes of the meander streams and the meander cut-off areas scattered all over the country except Samji Village and draw the characteristics from the comparative analysis.

A Study on the Recycling Package Design (재활용 포장디자인의 연구 - 마케팅을 중심으로 -)

  • 재활용
    • Archives of design research
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    • v.21
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    • pp.139-147
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    • 1997
  • The concept of package in these day is getting changing with fluctuation of living and management circumstance. The is due to society trancefiguration and change of economic structure and induced to appear small paxkage. These package trend to covert from the class management to total management system and these system made a promotion to development current industry. In these day, with the development of industry and the progress of the life , the package is performing the first faculty such as perservation of manufacture, convenience of keeping and loading in , expedition of sale and additionally the role of package in modern economy is significant for the essen tial element of enterprise prosperity by improving its shape color and materials. It is readilly appearent to anyone in the recycling field that stable markets for collected materials are vitals to any successful program. The recycling movement has increased in popularity throughout the any country: however, it has brought with it a market for them. This attitute also prevails in the political arena where atates or municipalities who are committed to recycling major portion of the solid waste stream are asking these same question regarding the disposition of thte recycled material.

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The Changing Process of the Tidal Landforms in Hampyeung Bay, Southwest Korea (함평만의 간석지 해안지형의 변화)

  • KIM, Nam-Shin;LEE, Min-Boo
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.223-233
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    • 2011
  • The aims of this study is about distribution characteristics of tidal coastal landforms, and that changing process in the Hampyeung Bay, which has a semi-enclosed bay like basin shape without inflow of stream, the mouth of open sea is narrow and forms with wide ends toward inland sea. The source of deposits are moved materials by tidal currents and from coastal slopes. Main landform elements of study area consist of tidal flat, tidal channels, intertidal sand bar, sea cliffs, and sea terrace. Tidal flats is classified with mud flat and mixed flat by grain size composition. Mud flats have developed at the shoreline area that tidal flat is closed to the continuity of gentle slope, and mixed flat developed at the foot of the sea cliffs and sea terraces. Quaternary deposits were identified in the coastal materials sedimented by the sea-level change. According to the analysis of grain size composition during last ten years, sands and silt has increased 2% and 6% respectively, clay has been decreased by 9%. The concaved tidal flats are colonized by salt plants. Areal changes of salt plants expanded near four times from 2.4km2 at the year 2001 to 9.3km2 at the year 2009. During the same periods, mean grain size became coarser from 6.5φ to 4.5φ at the salt plants area.

An approximate study on flood reduction effect depending upon weir or gate type of lateral overflow structure of washland (강변저류지 월류부에서 월류제 또는 수문 형식에 따른 홍수저감효과에 관한 개략적 연구)

  • Ahn, Tae Jin
    • Journal of Wetlands Research
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    • v.15 no.4
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    • pp.573-583
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    • 2013
  • Construction of large-scale structures such as dams would be suggested actively to cope with change of flood characteristics caused by climate change. However, due to environmental, economic and political issues, dams are not ideally constructed. Thus flood damage reduction planning projects would get started including washland or detention pond for sharing the flood in basin. The washland made artificially by human being is an area of floodplain surrounded by bank to be intentionally inundated by overflowing through overflow structure adjacent to main channel during flood season. Flood reduction capacity at just downstream of each washland could be affected by type, length, and crest elevation of overflow structure in addition to shape of design hydrograph, storage volume of washland, etc.. In this study flood reduction effects of washland are estimated for overflow weir type and gate type to compare the results of flood reduction respectively subjected to given hydrograph in sample site, the Cheongmicheon stream. It has been shown that even if gate type at overflow structure could yield more flood reduction than overflow weir type, economic aspect such as initial cost, operation cost and maintenance cost should be considered to select the type of overflow structure because flood reduction rate by gate type could not be significant value from engineering point of view.

A Case Study for Simulation of a Debris Flow with DEBRIS-2D at Inje, Korea (DEBRIS-2D를 이용한 인제지역 토석류 산사태 거동모사 사례 연구)

  • Chae, Byung-Gon;Liu, Ko-Fei;Kim, Man-Il
    • The Journal of Engineering Geology
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    • v.20 no.3
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    • pp.231-242
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    • 2010
  • In order to assess applicability of debris flow simulation on natural terrain in Korea, this study introduced the DEBRIS-2D program which had been developed by Liu and Huang (2006). For simulation of large debris flows composed of fine and coarse materials, DEBRIS-2D was developed using the constitutive relation proposed by Julien and Lan (1991). Based on the theory of DEBRIS-2D, this study selected a valley where a large debris flow was occurred on July 16th, 2006 at Deoksanri, Inje county, Korea. The simulation results show that all mass were already flowed into the stream at 10 minutes after starting. In 10minutes, the debris flow reached the first geological turn and an open area, resulting in slow velocity and changing its flow direction. After that, debris flow started accelerating again and it reached the village after 40 minutes. The maximum velocity is rather low between 1 m/sec and 2 m/sec. This is the reason why debris flow took 50 minutes to reach the village. The depth change of debris flow shows enormous effect of the valley shape. The simulated result is very similar to what happened in the field. It means that DEBRIS-2D program can be applied to the geologic and topographic conditions in Korea without large modification of analysis algorithm. However, it is necessary to determine optimal reference values of Korean geologic and topographic properties for more reliable simulation of debris flows.