• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.1
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• pp.10-16
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• 2018

The Republic of Korea Marine Corps is planning to develop a new amphibious assault vehicle which is able to operate with higher water speed than current KAAV. In order to achieve a higher water speed for hydrodynamically bulff-body vehicles, it is essential to develop drag reduction strategies. In this paper, resistance characteristics including trim angles of amphibious assault vehicles with several appendage designs are investigated using a commercial CFD code, STAR-CCM+. The computed results are compared with experimental data conducted at the towing tank with 1:4.5 scaled model and show good correlation. Comparing with the results of bare hull, 3.4 % of hydrodynamic drag and 52 % of trim angle are reduced by the application of double angled bow flap and a hydrofoil attached at the transom.

• Journal of the Korean Society of Costume
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• v.61 no.7
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• pp.135-151
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• 2011

The purpose of this study is to research the costume styles during the Silla(新羅), and Paekje dynasty[百濟] in 'Seodong tale'. In those days, costume form, color, pattern, and ornaments played an important role in representing the differences in social status. The Methodology of this study is reviewing and researching the symbolic meaning and classifying the types of the style of the Costume in 'Seodong tale' through the antique records and tombs bequests and expressing the clothing of the appearance people in the picture. This study is about the costume styles representing the differences in social status during the Silla and Baekje dynasty in 'Seodong tale'. Sedong wore 'Heug Geon(黑巾)' and 'Yu', 'Ko(袴)'. The king of Silla, Jinpyung wore Tree and Antler-typed Diadem and 'Po(袍)' with 'GwaDae(銙帶)' and Earrings, Necklaces, Rings. The servant of Baekje wore 'Eunmhwakwansik[silver crown]' and 'Jangyu' bound the silver belt and 'Ko'. Silla Princess of the court, Seonhwa wore Feathered Trim with Conical hat, and 'Yu' bound the belt and 'SangdongChima' and Earrings, Necklaces, Bracelets, Rings. Sedong's mother's hair style was 'Eonjeunmeori' and wore 'Yu' and 'Ko'. The queen of Baeje, Seonhwa wore 'Keumhwasik[Gold crown]', and 'Po' bound the belt and Earrings, Necklaces, Bracelets.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.303-328
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• 2015

A design methodology is presented to develop the hingeless control surfaces for MAV using adhesively bonded Macro Fiber Composite (MFC) actuators. These actuators have got the capability to deflect the trailing edge surfaces of the wing to attain the required maneuverability, besides achieving the set aerodynamic trim condition. A scheme involving design, analysis, fabrication and testing procedure has been adopted to realize the trailing edge morphing mechanism. The stiffness distribution of the composite MAV wing is tailored such that the induced deflection by piezoelectric actuation is approximately optimized. Through ground testing, the proposed concept has been demonstrated on a typical MAV structure. Electromechanical analysis is performed to evaluate the actuator performance and subsequently aeroelastic and 2D CFD analyses are carried out to see the functional requirements of wing trailing edge surfaces to behave as elevons. Efforts have been made to obtain the performance comparison of conventional control surfaces (elevons) with morphing wing trailing edge surfaces. A significant improvement in lift to drag ratio is noticed with morphed wing configuration in comparison to conventional wing. Further, it has been shown that the morphed wing trailing edge surfaces can be deployed as elevons for aerodynamic trim applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.331-335
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• 2004

In this paper, we modeling the oxidation, diffusion, and ion-implantation for semiconductor process simulation, and construct the integrated framework for efficient execution and continuous process simulation. For oxidation process, to predict the accurate LOCOS shape and stress distributions, stress-dependent viscous model was performed using SVP algorithm. For diffusion process, predeposition and OED simulation was performed using point defect theory. For ion implantation, Monte-Carlo method based on TRIM simulation was performed with various process conditions. For input to each unit process, we used the dialog boxes which are windows application's standards. This dialog box allows us to verify and minimize input error at input steps. Using the combination of compiler's function and windows's API function, simulation was done with small memory size.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.135-144
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• 2005

The Effects of intake swirl and combustion parameters on the performance and emission characteristics in a V8 type turbocharged intercooler D.I. diesel engine of the displacement $16.7\iota$ were studied experimentally in this paper. Generally the swirl in the combustion process of diesel engine promotes mixing of the injection fuel and the intake air. Also, TCI diesel engine is put to practically use intercooler in order to increase boost efficiency which is cooled boost air. As a result of steady flow test, when the swirl ratio is increased, the mean flow coefficient is decreased, whereas the Gulf factor is increased. And through engine test, its can be effected to meet performance and emission by optimizing the main parameters; the swirl ratio is 2.25, compression ratio is 17.5, combustion bowl is re-entrant $8.5^{\circ}$, nozzle hole diameter is $\phi0.33^{\ast}3+\phi0.35^{\ast}2$, injection timing is BTDC $12^{\circ}CA$ and turbocharger is T02 model which are compressor 0.6A/R+46trim and turbine 1.0A/R+57trim.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.3
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• pp.44-50
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• 2012

The noise reduction is important one of considerations in the process of a civil aircraft development program. External noise sources are classified into an air-born source and a structure-born source. Among these noise sources, the most affected noise source into a cabin is the air-born noise source from an engine or propeller. The external noise is transmitted into the cabin through the fuselage structure of airplane which are composed of an fuselage structure, an interior trim panel and an acoustic insulation layer between an fuselage structure and an interior trim panel. Therefore, appropriate fuselage structure and acoustic insulation layer is very important to reduce the internal noise level. In this paper, the vibro-acoustic coupled analysis of the cabin noise of the 80~90 seats regional turboprop aircraft is carried out to validate the acoustic analysis method using Direct BEM and FEM. The sound pressure level onto the fuselage skin is acquired by fan-source noise analysis using BEM, and which sound pressure is used as acoustic noise source in vibro-acoustic noise analysis for cabin noise analysis using FEM.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1079-1086
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• 2013

Optimal mount position of a front pillar trim considering heat resistant characteristics can be determined by two methods. One is conventional approximate optimization method which uses the statistical design of experiments (DOE) and response surface method (RSM). Generally, approximated optimum results are obtained through the iterative process by a trial and error. The quality of results depends seriously on the factors and levels assigned by a designer. The other is a methodology derived from previous work by the authors, which is called sequential design of experiments (SDOE), to reduce a trial and error procedure and to find an appropriate condition for using artificial neural network (ANN) systematically. An appropriate condition is determined from the iterative process based on the analysis of means. With this new technique and ANN, it is possible to find an optimum design accurately and efficiently.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.443-452
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• 2005

The purpose of this study is experimentally to analyze the effects of intake port swirl, injection system and turbocharger on the engine performance and the emission characteristics in a V8 type turbocharger intercooler D.I. diesel engine of the displacement 16.7L, and to suggest the improvement of engine performance. Generally to enhance engine power, TCI diesel engine is put to practically use turbocharged intercooler in order to increase volume efficiency which is cooled boost air. As results of considering the factors of the intake port of swirl ratio 2.25, compression ratio 17.5. re-entrant $8.5^{\circ}$ combustion bowl, nozzle hole diameter ${\phi}0.33{\ast}3+{\phi}0.35{\ast}2$. nozzle protrusion 3.18mm, injection timing BTDC $12^{\circ}CA$ and turbocharger(compressor 0.6A/R+46Trim. turbine 1.0 A/R+57Trim) is the best in the full load in the engine performance and the exhaust characteristics of NOx concentration. Therefore. their factors are appropriated as intake system, injection and turbocharger system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.859-870
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• 2021

KARI (Korea Aerospace Research Institute) is developing a design framework for the concept and preliminary design of eVTOL aircrafts. A low fidelity mission analysis tool was developed for the eVTOL aircrafts of Lift-Tilt Concept, which have tilt propellers and lift propellers, using open source SUAVE package. For its development, a review for the propeller performance analysis functionality was made. To find the trim solution at each mission segment automatically, an algorithm is implemented, using a global optimization technique through parallel processings and DOE(design of experiment). Using the tool, the one seated eVTOL OPPAV(optionally piloted personal air vehicle) was modeled and evaluated, which results were compared with the preliminary design data.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.32-39
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• 2021

Korean coastal fishery suffers from profitability degradation due to a decrease in fisheries resources, pollution in coastal waters, fuel coast increase, and market opening for aquaculture products. The next generation Korean fishing vessel aims at the improvement of energy efficiency, enhancement of crew welfare, and safety. These purposes can be accomplished by adopting a new standard hull form with improved resistance performance and a modernized residence facility on the deck. In order to improve resistance performance, this study attempts to optimize design variables for stern flaps for three kinds of fishing vessels - coastal multi-purpose, coastal trap, and dredged nets. A series of model tests for these fishing vessels was carried out in the towing tank of Pusan National University. The results indicate that for some cases, the stern flap caused the stern trim of the vessel to decrease, leading to the resistance reduction.