• Title/Summary/Keyword: Coast line

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Relationship between halophyte distribution and soil environmental factors in the west coast of South Korea

  • Lee, Seung Ho;Lee, Jeom-Sook;Kim, Jong-Wook
    • Journal of Ecology and Environment
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    • v.42 no.1
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    • pp.12-19
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    • 2018
  • Background: The objective of this study was to determine the relationship between soil environmental factors and halophyte distribution in the west coast of South Korea. Soils of our study sites were categorized into two groups: salt marsh and estuary marsh. Results: Salinity was higher in the salt marsh group than that in the estuary marsh group. However, total nitrogen, silt, and clay contents were higher in the estuary marsh group than those in the salt marsh group. Although altitude had a wider range in the salt marsh group, the mean altitude was higher in the estuary marsh group than that in the salt marsh group. Annual halophytes of seed propagation species were distributed parallel to the coast line on salt marsh. Higher coverage of vegetation was found in the area closer to the coast line. Plant density was higher near dead parental plants in estuary marsh, showing less difference in area that was more distant from the coast line. Conclusions: Results of canonical correspondence analysis (CCA) for vegetation distribution and sediment environmental factors and germination analysis in the coast line showed significant relationship with halophyte distribution. Therefore, they can be used as an indicator of coastal plant movement due to sea level rise.

High-speed Rail Infrastructure Priority Decision Making on Level of Design Speed by Rail Network Design Problem (철도망 설계모형을 이용한 설계속도 수준별 고속철도망 투자우선순위 선정)

  • Park, Jin-Kyung;Lim, Yong-Taek;Lee, Jun;Eom, Jin-Ki;Moon, Dae-Seop
    • Journal of the Korean Society for Railway
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    • v.12 no.3
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    • pp.427-436
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    • 2009
  • This paper introduced Railway Network Design Problem (RNDP) to provide priority decisions on high-speed railway investment scenarios defined by various network segments and train systems. The RNDP optimizes the objective functions of minimize total travel time. Results show that the priority of high-speed railway investment is found to be East-west, West-coast, and South-coast line respectively. An entirely new line built with 400km/h is found to be the best alternative to East-west line. Regarding West-coast and South-coast line, the combined alternative of upgrading Geolla and Kyeonjon line with 200km/h and building a new line with 400km/h and 350km/h for remains of each line is the best.

Geotechnical parameters from pressuremeter tests for MRT Blue Line extension in Bangkok

  • Likitlersuang, Suched;Surarak, Chanaton;Wanatowski, Dariusz;Oh, Erwin;Balasubramaniam, Arumugam
    • Geomechanics and Engineering
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    • v.5 no.2
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    • pp.99-118
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    • 2013
  • Construction of the extension project of the Bangkok MRT Blue Line underground railway was recently started in 2011. The construction of approximately 5 km long underground tunnel and 4 deep excavations of underground station are considered to be the most important geotechnical works. The pressuremeter was selected as a high-quality in situ testing of the soil to evaluate design parameters for the project. In addition, other field and laboratory tests such as vane shear and $CK_0U$ triaxial tests were included in the investigation programme. This paper aims to present the ground conditions encountered along the MRT Blue Line extension project as well as the site investigation and interpretation techniques with particular focus on the pressuremeter tests. The results are also compared with the pressuremeter investigation from the previous Bangkok MRT project.

A Study on the Design of Fatigue Strength using Fractal Character of Surface Micro-crack (표면미소균열의 프랙탈 특성을 이용한 피로강도설계에 관한 연구)

  • Cho, Seok-Swoo;Joo, Won-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.143-151
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    • 1999
  • The shape of surface micro-crack is very irregular due to nonhomogeneous microstructure but is very important in respect to qualitative estimation of fatigue life. Fractal geomety can quantify the shape of surface mciro-crack. Fractal dimension is measured for surface micro-cracks with coast line and box counting method and estimates cycle ration in Al 2024-T3. The average fractal dimension $D_{favg}$ of surface micro-cracks has 3-parameter weibull distribution and location parameter is nearly constant but shape parameter decreases as cycle ration increases. The fractal dimension by coast line method is measured for individual surface micro-crack but the fractal dimension by box countin method is measured for all the surface micro-cracks under sampling area. Therefore, This paper shows fractal dimension $D_{fb}$ can predict cycle ratio $N/N_f$ more convenient than fractal dimension $D_{favg}$.

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Astudy on the classification of Eastern Coastal line of korea from the view point of Prevailing Wave Direction (탁월파랑에 의한 동해안선 분류의 조사연구)

  • 이원환;이정태
    • Water for future
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    • v.11 no.1
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    • pp.39-46
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    • 1978
  • The approaching deep water wave heights and directions affect the wave energy which is carried to the coast. By studing the relations between the longshore wave energy theory and the evolution of coastline, writer can arrive following conclusion. The longshore lottoral drifting affects to a great deal the formation of the coast, and by investigating on the eastern coastal geomophorogy of korea, the theory was proued as a true and made it possible to an approaching to the subdivided classification of eastern coast of lorea. That is to asy that angle taken by the level between the wave crest line of prevailing wave(NE) and the coastline was measured as less than 15#, and in the area neighboring the river which served as source of Sand parrticles, there are grand scale formation of sand beach expectable, in the other hand the formation of sand beach in case of $35^{\circ}{\leq}{\alpha }o{\leq}55^{\circ}$ which represents the vivid phenomena of longshore littoral drifting was proved not influencial but rather transformed into a rocky coast. Depending on the above facts the writer classified general shape of the coast affected by the vivid wave action into the following three, (1) The equilibrium beach. (2) Erosinal beach. (3) Geomophorogical beach, and made the sandy and rocky coast are subdivided as S-A.B.C. and R-DEF.

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The Analysis of the Coastline Data Registered in Cadastral Records (해안토지의 지적공부등록실태 연구)

  • Choi, Gyu-Myeong;Kwon, Jay-Hyoun;Choi, Yun-Soo
    • Journal of Korean Society for Geospatial Information Science
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    • v.14 no.4 s.38
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    • pp.45-51
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    • 2006
  • Recently the coast is an important area in terms of spatial land use and natural environment conservation such as the expansion of a national land and the development of a coastal industrial zone in Korea. We can not provide a proper solution for a boundary determination raised by a land ownership dispute due to the insufficient coast land registration. We observed the status of the coast land registration and analyzed the problem through the investigation of the difference between a land title and a coast land in the study area. We selected the west coast with the big difference between the ebb and flow of the tide as the study area from a paper review, compared a cadastral line with a coast line and suggested a good guideline to solve the problem through understanding the status of the coast land title registration in Korea.

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Assessment and Improvement of Ocean Physics for Coastal Erosion Projects (연안침식방지사업의 해양물리분야 평가실태 및 개선방안)

  • TAC, Daeho;OH, Hyuntaik
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.4
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    • pp.947-956
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    • 2016
  • This study analysed the documents of Sea Area Utilization Consultation of JongChun and ApHae located in West Coast of Korea and NaJeong located in East Coast of Korea in order to find out problems of site surveys and numerical simulations for coastal erosion projects of ocean physics, and suggested the improvement way to go. Current especially like wave-induced current is the one of the important external forces to handle coastal erosion but underestimated in the west coast. In case of east coast the various tests including wave-induced current were conducted but less efficient to find out the reasons of coastal erosion. The stiffness structure to protect coastal line like beach made the secondary erosion by using them without sufficient analysis for the erosion. In order to consult a Sea Area Utilization Consultation those are needed to review the scenarios for external forces such as wave and tidal currents, the site surveys for external forces, the net sediment analysis for years, the long periods of monitoring, and the guide line and revision of the rule for coastal erosion.

Variation of the Sea Level in the Korean seas Using Altimeter Data (TOPEX/POSEIDON)

  • Seo, Won-Chan;Yoon, Hong-Joo
    • Journal of information and communication convergence engineering
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    • v.6 no.4
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    • pp.430-433
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    • 2008
  • A merged altimeter data products are used to estimate sea level variation in the East Sea between 1993 and 2006. The altimeter data show a high correlation coefficient (0.85) after applying gaussian low pass filter for 180days at Ulleung island. The both of Mukho coast and Ulleung island are minimal sea level in March to May and maximal in September to November. Sea level of Mukho coast is higher than that of Ulleung island during March to May, while Mukho coast is lower during September to November because the North Korea Cold Current flows along the coast line of Mukho. Generally sea level variation at Mukho coast and Ulleung island associated with seasonal variations.

Transplantation of Koelreuteria paniculata by Sea Current (모감주나무의 해류에 의한 전파)

  • 이영노
    • Journal of Plant Biology
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    • v.1 no.1
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    • pp.11-20
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    • 1958
  • I. Assumption: Mo-kam-ju, Koelreuteria paniculata is a woody plant mainly cistributed over Northern China. Its sporadic growth along the beaches of Korea and Japan is assumed to have been sowed by the seeds transported adrift on the current across the ocean. II. Use and Growth of the Plant: In China, this plant has been cultivated from early times mainly at temples, it seeds being used as rosaries, its flowers for yellow dyes and medicine for the eyes, and its leaves for black dyes. In Korea and Japan, these plants have been cultivated at temples and used as the material for rosaries. No natural growth of these plants was reported until 1919. III. Discoveries: In this domestic area, Dr. Chung Tae Hyun discovered the plant on the beach between Cho-Do and Chang-san-kot, Hwang-Hae Prov. in 1920. The reporter discovered them on the beach at Buk-Ni, Duk-jok-Do in 1948, at An-Hung in 1956 and on the beach at An-min-Do in 1957. In the Japan area, it was discovered for the first time twenty years ago, mainly along the coast line of the Japan Sea and some along the eastern coast line, at Subo, Yamaguchi Prefecture facing the Pacific Ocean. IV. Study and Experiment: A. Seed The seed coat is thick, non-permeable and floatable. A number of seeds were immersed in artificial sea water and fresh water separately. The seeds remained there for a hundred and forty-five (145) days from April 6, 1957 to August 29, 57. Thirty one seeds out of the fifty immersed in salt water and twenty seeds out of the fifty immersed in fresh water remained on the surface of the water, proving them to be non-permeable to both sea and fresh water. Of course, these had retained their germinating capabilities. Five (5) seeds out of twenty from the fresh water and six (6) out of thirty-one from the sea water were successfully germinated after a hole had been drilled in the seed coat and they had been planted. Thus their floating capability, non-permeability and germinating capability after a possible 145 day trip on the flowing currents has been proved satisfactory according to the assumption made above. B. Current As shown in the Data 2 and 3, the sea current initiated in the Pohai Sea flows westward down along the coast line of Korea reaching the southern part during the autumn and winter seasons. This fact also is in favor of the reporter's assumption. V. Discussion and Conclusion: The reporter concludes that, as discussed above, Koelreuteria paniculata which originates in Northern China is transported adrift on the flowing sea current to our western coast line, and also the coast lines of Shantung and Kuangtung of China and it is germinated on the sandy beaches forming new plants. Thus, the seeds drifted down on the southern beach of Korea and have been transported to the Japanese coast, adrift on the Tae-Ma current. Upon fruition, the seeds of the plants which settle on the coasts of western Korea and Japan will migrate to new places. It can be, however, assumed that while the thickness and nonpermeability of the coat enables the long travel in the water, this also can compose a difficulty in germination, consequently in developing a new distribution of this species.

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A Study on the Improvement of Trolling Equipment for Spanish Mackerel and Yellow Tail in the Coast of Jeju island (제주 연근해 삼치·방어용 끌낚시의 조업 장비 개발)

  • Park, Young-Seok;Kim, Byung-Yeob;Lee, Chang-Heon
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.2
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    • pp.422-429
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    • 2015
  • The purpose of this study is the improvement of the existing trolling hauler, which has only one wheel to wind a main line, for saving man power around the coast of Jeju island. The trolling hauler manufactured for a test performance consisted of the wheel part of a main line and the roller part of a leader line including labor-saving devices comprised of a friction clutch, a fastener and springs. Even though this existing electric hauler system is convenient to control the wheel speed and the winding direction, it is apt to cost high and to corrode quickly at sea. Therefore, to remove these negative elements and to operate rollers for hoisting a leader line of the trolling, hydraulic motors were used separately. As a result, according to using of labor-saving devices, the towing tension occurred in operating in fishing ground could be selected moderately without breaking of lines and the operating efficiency of the trolling hauler was verified.