• Title/Summary/Keyword: Beach Evolution

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Two Newly Recorded Ciliates, Oxytricha balladyna and O. longa (Ciliophora: Spirotrichea: Sporadotrichida) from Korea (한국산 2미기록종 Oxytricha balladyna와 O. longa (유모문: 다막강: 하모목))

  • Kwon Choon Bong;Shin Mann Kyoon
    • Animal Systematics, Evolution and Diversity
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    • v.20 no.2
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    • pp.171-178
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    • 2004
  • Two oxytrichid ciliates collected from the two habitats (soil under pine forest near beach and sewage treatment plant) in Korea were identified as Oxytricha balladyna Song and Wilbert, 1989 and O. longa Gelei and Szabados, 1950. These species are reported in this paper for the first time from Korea. The description was based on the observation of living specimens and protargol impregnated specimens. Diagnostic characteristics for each species are as follows. O. balladyna: one micronucleus located between two macronuclei, five transverse cirri, three caudal cirri, five rows of dorsal kinety, no granule in cytoplasm. O. longa: each micronucleus closely located near two macronuclei, three postoral ventral cirri lying in a straight line and positioned far away from transverse cirri, four transverse cirri, two caudal cirri, four rows of dorsal kinety, yellow-green granules scattered on cytoplasm.

Numerical Analysis of Nonlinear Shoaling Process of Random Waves - Centered on the Evolution of Wave Height Distribution at the Varying Stages of Shoaling Process (불규칙 파랑 비선형 천수 과정 수치해석 - 천수 단계별 파고분포 변화를 중심으로)

  • Kim, Yong Hee;Cho, Yong Jun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.2
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    • pp.106-121
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    • 2020
  • In order to make harbor outskirt facilities robust using the reliability-based design, probabilistic models of wave heights at varying stage of shoaling process optimized for Korean sea waves are prerequisite. In this rationale, we numerically simulate the nonlinear shoaling process of random waves over the beach with a sandbar at its foreshore. In doing so, comprehensive numerical models made of spatially filtered Navier-Stokes Eq., LES [Large Eddy Simulation], dynamic Smagorinsky turbulence closure were used. Considering the characteristics of swells observed at the east coast of Korean Peninsula, random waves were simulated using JONSWAP wave spectrum of various peak enhancement coefficients and random phase method. The coefficients of probabilistic models proposed in this study are estimated from the results of frequency analysis of wave crests and its associated trough detected by Wave by Wave Analysis of the time series of numerically simulated free surface displacements based on the threshold crossing method. Numerical results show that Modified Glukhovskiy wave height distribution, the most referred probabilistic models at finite water depth in the literature, over-predicts the occurring probability of relatively large and small wave heights, and under predicts the occurrence rate of waves of moderate heights. On the other hand, probabilistic models developed in this study show vary encouraging agreements. In addition, the discrepancy of the Modified Glukhovskiy distribution from the measured one are most visible over the surf zone, and as a result, the Modified Glukhovskiy distribution should be applied with caution for the reliability-based design of harbor outskirt facilities deployed near the surf-zone.