• 한국항해학회지
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• 제21권1호
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• pp.103-108
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• 1997

Mathematical model of maneuvering motion for a single-screw single-rudder ship is established and several applications to the special situations of maneuvering are attempted. While, the mathematical model for twin-screw twin-rudder ship is not presented so much, because that type of ship is not popular. Lee et al. have examined the characteristics of such ship by captive model tests in 1988, in Japan. This paper proposes new mathematical models for propeller effective wake (1 -${\omega}_p$) and effective neutral rudder angle ${delta}_R$ in the case of twin-screw twin-rudder ship. And some maneuvering motionse are calculated with proposed models and compared with exact simulations.

• 대한조선학회논문집
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• 제43권4호
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• pp.399-413
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• 2006

Mathematical model for coupled motions of Manta-type Unmanned Undersea Vehicle(UUV) moving with six degrees of freedom, is formulated. Furthermore, a calculation method for estimating the linear hydrodynamic derivatives acting on UUV, is proposed, and some of the estimated linear hydrodynamic derivatives are compared with results of captive model experiment. Based on linear dynamic model of UUV, a study was made to examine dynamic stability and turning ability in horizontal plane. And directional stability and required elevation rudder angles for neutrally operating in vertical plane, are also discussed.

• 한국기계연구소 소보
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• 통권10호
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• pp.35-48
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• 1983

When the hydrodynamic coefficients of the ship maneuvering equation are estimated by captive model test, it is difficult to take account of the scale effect between model and full scale ship. This scale effect problem can be overcome by processing the sea trial data with system identification. Extended Kalman filter is used as a system identification technique for the modification of the simulation equation as well as the estimation of hydrodynamic coefficients. The phenomena of simultaneous drifting of linear coefficients occur. It is confirmed that two coefficients in each pair-($Y_v$', $Y_r$' -m' u'), ($N_v$', $N_r$' )-are simultaneously drifting and all 4 coefficients are simultaneously drifting together. Particularly simultaneous drifting of 2 coefficients in each pair is more significant. It is also shown that the simultaneous drifting of 4 coefficients can be reduced by choosing the input data which have the random v'/r' curve and 4 coefficients are estimated within 2-4% error, which may be noise level. So, it is recommended to operate the rudder randomly in sea trial or model test for the application of system identification technique.

• Journal of Positioning, Navigation, and Timing
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• 제9권2호
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• pp.125-129
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• 2020

In this paper, Zero velocity UPdaTe (ZUPT) is implemented on the navigation system of Remotely Piloted Aircraft for GNSS denied environment. RPA's navigation system suffers from lack or loss of satellite signal while maintenance or ground test inside a hangar. Although some of the hangars install GPS repeaters for indoor tests, the anti-jamming equipment with array antenna blocks the repeater signal regarding them as hostile jamming signal. With ZUPT, an aircraft navigation system can be tested free from the divergence of navigation solution without line-of-sight satellites. The designed ZUPT aided centralized Kalman Filter is implemented on the Embedded GPS&INS and simulated with Captive Flight Test data. The simulation result shows stable navigation solution without GNSS updates.

• 한국항해학회지
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• 제18권3호
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• pp.11-18
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• 1994

In the present trends at which vessels would be supersizedly designed for adapting special cargoes in order for effective controls of logistics in marine transportation, it brings poor manoeuvrability of ships and makes environmental or economical loss seriously due to accidents of a large scale at sea. International Maritime Organization adopted manoeuvring standards and also recommended manoeuvring booklets for ship operators recently. We attempted to find variation of hydrodynamic derivatives when a bare hull was fitted with propeller and rudder, or propeller only by captive model test in the circulating water channel. On comparing experimental results with theoretical values derived from equations, almost same tenden-cies were found at hull-propeller-rudder and hull-propeller situations. Interactions with rudder displayed well at large drift angles.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.824-831
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• 2005

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree, which was expected in the initial design stage. It is thought to be the useful informations that the keel has an effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition. Also this paper is associated with the state-of-the-art of calculating sailing yacht performance as this is performed in velocity prediction program (VPP). The VPP results shows a typical shape of a sailing yacht and the designed yacht has the best performance at 120 degree angle of true wind with 20 knots.

• 한국수정란이식학회지
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• 제25권4호
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• pp.287-290
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• 2010

On January 6, 2010, two months earlier than normal breeding season, a red fox vixen was implanted with synthetic GnRH analogue, Deslorelin. Blood was sampled every 2~3 days from the day of implant to identifying spermatozoa on stains of epithelial cells. Estradiol and progesterone were examined. Even though the vixen was in non-breeding season, she was mated by a male fox. Pregnancy was confirmed by canine pregnancy detection kit that detect relaxin released from placenta. Four healthy pups were born on March 9, 2010. This is the first report showing synthetic GnRH can activate ovarian function and lead to fertile estrus of red fox in non-breeding season.

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2009년도 추계학술대회
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• pp.269-269
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• 2009

• 대한수의학회지
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• 제45권3호
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• pp.381-385
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• 2005

Aeromonas hydrophilia infection was diagnosed in captive Jackass penguins (Spheniscus demersus). Seven Jackass penguins showed clinical signs including depression and anorexia with greenish vomiting, but four penguins were died although extensive treatment was carried out. At necropsy, the penguins appeared to have hemorrhage and catarrhal inflammation of the small and large intestines and severe enlargement of the right hepatic lobe, elongation of the gall bladder and pyloric ulceration of the stomach. The ovaries observed atrophy and congestion. Microscopically, there were congestion, fat droplet within the cytoplasm of the hepatic cell, infiltration of lymphocytes in the stomach, vilous detachment and destroyed glandular epithelium in the small and large intestines. Aeromonas hydrophilia was isolated from the liver and small intestines. This case is the first report of an occurrence of Aeromonas hydrophilia infection at Jackass penguins in Korea.

• 대한조선학회논문집
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• 제42권3호
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• pp.233-240
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• 2005

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree, which was expected in the initial design stage. It is thought to be the useful informations that the keel has au effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition.