• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.155-155
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• 2018

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.109-115
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• 2006

An overview of 30 feet sailing yacht design is presented. with an emphasis on the factors contributing to start-up Popularization . After prescribing the configurations of the purposed yacht. the design of the hull form with a rudder and a keel, are schematically described. Also the determinations of the dimensions of the sail and rig are performed.

• Animal cells and systems
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• v.12 no.3
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• pp.157-163
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• 2008

Paradexamine jindoensis n. sp. belonging to family Dexaminidae was collected from Jindo Island, Korea. The new species is fully illustrated and compared with related congeners. The new species resembles highly P. houtete, in having the tooth formulae of dorsal pleonites, 1-3-3-3, rear to front and in bearing short spines on the mandible. However, it is characteristic in having the several morphological differences of mouth parts, slender appendages, and longer peduncular article 2 of antenna 1 than article 1.

• Mycobiology
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• v.34 no.1
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• pp.41-43
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• 2006

Two species of the Laboubeniales based on the Tibetan collections are described. They are new to the mycological flora of Tibet. Laboulbenia polyphaga found on several parts of Amara majuscula was characterized by having the outer appendages not ramified and simple. Peyritschiella protea obtained on the lower abdomen of Philonthus wuesthoffi, had two perithecia and two antheridia produced on the third layer of receptacle.

• Journal of Plant Biology
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• v.31 no.1
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• pp.51-68
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• 1988

To clarity the species of genus Melandrium (Caryophyllaceae) in Korea, the taxonomic characters were described and interspecific relationships were discussed to the extemal morphology with light and scanning electron microscopy. The position and size of appendages on petal, the shape and venation pattern of leaf, and the external morphology of seed and pollen were approved as the good characters to classify genus Melandrium in Korea. As the result, genus Melandrium in Korea could be arranged as 6 species, 1 variety, 1 forma. M. umbellatum was exclusively distributed in north Korea, and its taxonomic treatment was reserved.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.529-534
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• 2014

Pyrotechnic devices are widely used for space appendages. However, a cube satellite requirements do not permit the use of explosive pyrotechnic device. A nichrome burn wire release has typically been used for holding and release of deployable appendages of the cube satellite due to its simplicity and low cost. However, relatively low mechanical constraint force and system complexity for application of multi-deployable systems are disadvantages of the conventional mechanism. To overcome these drawbacks, we developed a hinge driving segmented nut type holding and release mechanism based on the nichrome burn wire release. The functional performance of the mechanism has been verified through release function test, static load test and shock level measurement test.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.5
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• pp.484-491
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• 2017

Recent research has shown that quadrupole noise has a significant influence on the overall characteristics of flow-induced noise and on the performance of underwater appendages such as sonar domes. However, advanced research generally uses the Ffowcs Williams-Hawkings analogy without considering the quadrupole source to reduce computational cost. In this study, flow-induced noise is predicted by using an LES turbulence model and a developed formulation, called the formulation Q1As method to properly take into account the quadrupole source. The noise around a circular cylinder in an underwater environment is examined for two cases with different velocities. The results from the method are compared to those obtained from the experiments and the permeable FW-H method. The results are in good agreement with the experimental data, with a difference of less than 1 dB, which indicates that the formulation Q1As method is suitable for use in predicting quadrupole noise around underwater appendages.

• 대한공업교육학회지
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• v.31 no.2
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• pp.364-380
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• 2006

This paper presents a procedure for designing command to maneuver flexible structure with very little residual vibration, even in the presence of modeling errors. For the open loop maneuver, the various shaped profiles using multiple step inputs delayed in time are considered for robustness and compared with the responses of rigid body and flexible body in virtue of simulations and experiments. Input shaping generates vibration-reducing shaped commands through convolution of an impulse sequence with the desired command. A flexible model with a cylindrical hub and four symmetric appendages is considered to examine the responses to real plant, and to illustrate the effectiveness of the proposed shapers. The appendages are long and flexible, leading to low frequency vibration under any control action. It is shown by a series of simulation that a properly designed feedback controller with input shaper performs well, as compared with open loop controller with input shaper. The control objective is to achieve a fast settling time of residual vibration to flexible structure and robustness (insensitivity)to plant uncertainty, to eliminate residual vibration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.601-608
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• 2019

In this study, the effect of hull appendages on the high-speed catamarans with reverse bow shapes is compared and analyzed by numerical analysis and circulating water tank model test. The reverse bow shape showed an improved wave shape by shifting the generation position of forward divergent wave to the stern direction and was effective in resistance and stable running posture (Kim et al., 2019). In the model test results of the running performance as the wave patterns and the change of the running posture due to the fin fitted with the inner side of the inverted bow and the interceptor, 1) Trim characteristics of the inverted bow 2) Improvement of superposition of inner wave by Fin 3) The trim control by the fin and the interceptor is considered to be effective in reducing the impact of the two hull connection decks (wetdeck).

• Journal of the Society of Naval Architects of Korea
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• v.60 no.1
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• pp.1-9
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• 2023

In order to improve the propeller cavitation performance composed of Cavitation Inception Speed (CIS), cavitation extent and pressure fluctuation, it needs to improve the wake distribution that flows into the propeller. The warship propeller cavitation is strongly influenced by the wake created at the V-strut of various appendages. The inflow characteristics of the V-strut were investigated using Computational Fluid Dynamics (CFD) and the twisted angles of the V-strut were aligned with upstream flow. The resistance and self-propulsion tests for the model ship with the existing and modified V-struts were conducted in Towing Tank (TT), and wake distribution, CIS, cavitation observation and pressure fluctuation tests were conducted in Large Cavitation Tunnel (LCT). The propeller behind the modified V-strut showed better cavitation characteristics than that behind the existing V-strut. Another model test was conducted to investigate rudder cavitation performance by the change of the V-strut. The rudder cavitation characteristics were not improved by the change of the operating conditions. On the basis of the present study, it is thought that the stern appendages for better propeller cavitation performance would be developed.