• Title/Summary/Keyword: Land crab

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Influence of roadkill during breeding migration on the sex ratio of land crab (Sesarma haematoche)

  • Ryu, Mi;Kim, Jae Geun
    • Journal of Ecology and Environment
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    • v.44 no.4
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    • pp.207-211
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    • 2020
  • Adult land crabs generally live on land while their larvae live in the sea. In the case of Sesarma haematoche, female crabs migrate from land to sea to release the larvae at the high tide of syzygy night. Artificial structures along coastal areas are being obstacles for the migration of land crabs and causing synchronized roadkills on coastal roads during breeding migration. In this research, we compared the sex ratios of crab populations in coastal areas with coastal roads and uninhabited island areas with no road. The proportion of females in inland habitats with coastal roads was significantly smaller than island habitats. In particular, females are exposed to the risk of annually repeated roadkills, and the proportion of females decreases rapidly with their growth. If this tendency is general for land crab populations in the coastal areas with roads, significant road mortality of female land crabs during breeding migration can lead to severe population decline in coastal areas. Therefore, it is necessary to take an action to save land crabs crossing coastal roads.

The Empirical Study on the Crosswind Landings (측풍 착륙에 관한 실증적 연구;B747-400의 착륙 사례를 중심으로)

  • Kim, C.Y.;Moon, B.S.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.12 no.2
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    • pp.71-81
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    • 2004
  • There are four methods of landing of B747-400 during the crosswind condition. Pilots can choose either one of them. Those are: Sideslip/Wing low, De-Crab during Flare, Touchdown in Crab, Combining Crab and Sideslip. They decide to use one method by what they have learnt before. During the flight, the pilots choose the method, which depends on the weather forecast, and then try to land according to it. However, the weather condition always changes. In other words, the weather during planning and landing can be different, which can provide a difference between the previously expected situation and the actual one. Therefore, it is very important for the pilots to have the situation awareness. This study shows the direction and the prevention to avoid those errors, which are based on actual landing data of B747-400.

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Oceanographic Condition and Fishing Condition of the Set Net Fishing Ground in Yeosu Bay (여수연해 정치망어장의 해황과 어황에 관한 연구)

  • Kim, Dong-Soo;Lee, Cho-Chool;Park, Yong-Seak
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.24 no.4
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    • pp.150-157
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    • 1988
  • The oceanographic condition around the set net fishing ground in Yeosu Bay was investigated by the oceanographic observation in June, July and August, 1988. Also the catch of the set net was analized by daly catch data of the three set net fishing ground from April to September, 1988. The results obtained are as follows: 1) The coastal surface water is high temperature and low salinity through the influence of land, and the off shore water and bottom water are low temperature and high salinity. 2) The eddy current and the sharp thermocline in June appeared in August at the set net fishing ground, and a good catch appeared in June and August. 3) The surface temperature and salinity at the set net fishing ground are 11$^{\circ}C$ to 27$^{\circ}C$ and 31.60$\textperthousand$ to 34.80$\textperthousand$. The surface temperature and salinity of a maximum good catch are 21$^{\circ}C$ and 33.80$\textperthousand$ to 33.99$\textperthousand$ respectively. 4) The dominant species of fish were spanish mackerel, scad, anchovy, sardine, common mackerel, hairtail, crab, yellow tail, in order of catch.

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A Study on the Transformation in Design Process of Ronchamp Chapel (롱샹 성당의 설계 변형 과정 연구)

  • Lee, Jeong-Kyu
    • Journal of architectural history
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    • v.8 no.1 s.18
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    • pp.81-94
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    • 1999
  • This Study aims at searching the meanings in the creative process of Ronchamp chapel by analyzing the drawings of the site, plan, section and elevation in chronological order. The origins of his architectural creation are identifying with the site(memories of Acropolis), analogies of crab shell, air plane wing and hydraulic dams. The architect informed himself about the site ,the tradition of pilgrimage associated with the place, and its devotion to the Holy Virgin; he looked into the rituals of the Catholic religion, spoke with ecclesiastics; he studied and annotated a monograph devoted to the site of Ronchamp. Also ,the plan required that it be possible to collect rainwater, since such was rare on the hill. In the first design phase, overall conception of building was carried out in the sketches and drawings from June 1950 to November 1950. The second phase in the elaboration of the project was from January 1951(at which time preliminary project was presented to the Commission of Holy Art) to April 1953. The modifications made were in response to opinions expressed by the patrons. The building moved to east and gargoyle moved to west, then, the elevations of north and west were changed. He designed the artificial land and bell tower from the first phase even after the beginning of construction ,he wanted them to be built .But they were not constructed, so the outer space for rituals of religion had no tension. I concluded that Le Corbusier had gifted ability and efforts to create spontaneous birth(after incubation) of the whole work, and the execution of drawings itself. He devoted himself to accomplish the project in spite of the change in situation or by clients.

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Development of a Legged Walking Robot Based on Jansen Kinetics (얀센 키네틱스를 기반으로 한 보행 로봇 개발)

  • Kim, Sun-Wook;Kim, Yeoun-Gyun;Jung, Hah-Min;Lee, Se-Han;Hwang, Seung-Gook;Kim, Dong-Hun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.4
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    • pp.509-515
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    • 2010
  • In this paper, the mechanism that can walk efficiently in wet land or sand area is proposed. A vision camera is attached to the mechanism, which makes a kind of biologically inspired robot for coast guard. This visionary information enables the biologically inspired robot to react in peripheral environment by a soft-computing algorithm. In addition, the biologically inspired robot can achieve the mission appointed by a programmer connecting with outside, based on RF and Blue-tooth communication module. Therefore, the purpose of this research is the implementation of the biologically inspired robot that can operate most adaptively in sand and wet surface based on Theo Jansen mechanism.