• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.478-487
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• 2014

The simplified performance analysis and initial configuration design are required for the successful development of UAV during the conceptual design, in which empirical formulas and trend equations are utilized for the UAV performance analysis. In the conceptual design phase various UAV configurations may be considered, however, it is very inefficient and unnecessary to consider all configurations for the conceptual design. In this study, the database for the fixed wing UAVs whose MTOW is between 50kg and 1,500kg was also constructed for the selection of configuration frequently used. The parametric analyses were performed for major performance parameters, and trend equations were developed through regression analyses for these individual performance parameters.

• The Bulletin of The Korean Astronomical Society
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• v.24 no.2
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• pp.72-72
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• 1999

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.130-141
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• 2002

• International Journal of Aeronautical and Space Sciences
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• v.15 no.4
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• pp.366-373
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• 2014

A conceptual design of a three-surface strike fighter was studied and stealth performance was taken into account to enhance survivability and battle effectiveness. CATIA was used to design the aircraft's three-dimensional prototype model and the weapon carriage arrangement was also studied. The aircraft's RCS characteristics and distributions under X, S, C, and L bands were simulated using the RCSPlus software, which is based on the PO method. Pressure and velocity distributions of the flow field were also simulated using CFD. A turbulence model was based on standard $k-{\varepsilon}$ function and N-S functions were used during the CFD computation. Lift coefficients, drag coefficients, and lift-to-drag ratio were obtained by aerodynamic simulation. The results showed that: (1) the average value of head-on RCS between ${\pm}30^{\circ}$ is below -3.197 dBsm, and (2) the lift coefficient is 0.34674, the drag coefficient is 0.04275, and the lift-to-drag ratio is 8.11087 when the attack angle is $2.5^{\circ}$.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.4
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• pp.383-395
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• 2014

According to the requirement of wing weight estimation and frequent adjustments during aircraft conceptual design, a wing weight estimation method considering the constraints of structural strength and stiffness is proposed to help designers make wing weight estimations rapidly and accurately. This method implements weight predictions on the basis of structure weight optimization with stiffness constraints and strength constraints, which include achievement of wing shape parametric modeling, rapid structure layout, finite element (FE) model automated generation, load calculation, structure analysis, weight optimization, and weight computed based on modeling. A software tool is developed with this wing weight estimation method. This software can realize the whole process of wing weight estimation with the method and the workload of wing weight estimation is reduced because much of the work can be completed by the software. Finally, an example is given to illustrate that this weight estimation method is effective.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.805-815
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• 2007

In order to build a conceptual design program for a liquid rocket engine system, performance based sub-programs for each core component of the engine system were made. Parts included were the combustion chamber, supersonic nozzle, centrifugal pump, and impulsive turbine. Simple mathematical models based on classical thermodynamic and inviscid theories were adopted with proper tuning by empirical data. In Part I, aiming to validate each sub-program, we examined the results of each program qualitatively, and parametrically investigated the sensitivity due to the change in design parameters.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_1
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• pp.565-574
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• 2007

Because of most current cadastral systems maintain 2D geometric descriptions of parcels linked to administrative records, the system may not reflect current tendency to use space above and under the surface. The land has been used in multi-levels, e.g. constructions of multi-used complex buildings, subways and infrastructure above/under the ground. This cadastre situation of multilevel use of lands cannot be defined as cadastre objects (2D parcel-based) in the cadastre systems. This trend has requested a new system in which right to land is clearly and indisputably recorded because a right of ownership on a parcel relates to a space in 3D, not any more relates to 2D surface area. Therefore, this article proposes a 3D spatial data model to represent geometrical and topological data of 3D (property) situation on multilevel uses of lands in 3D cadastre systems, and a conceptual 3D cadastral model in Korea to design a conceptual schema for a 3D cadastre. Lastly, this paper presents the results of an experimental implementation of the 3D Cadastre to perform topological analyses based on 3D Network Data Model to identify spatial neighbors.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.1
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• pp.93-103
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• 2005

SEDT(System Engineering Design Tool) has been developed for small satellite conceptual design with an aim to verifying the nanosatellite HAUSAT-2 design. The program can calculate the mass and power of whole satellite system having specific mission and estimate the system cost based on mission and user requirements. It is containing various analysis data of more than 200 small satellites. The database will provide the trend analysis results of the small satellites which will become important design factors. This tool has also been verified by applying more than 10 small satellite data through case studies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.1-9
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• 2004

The performance analysis code has been developed for vertical take-off and landing(VTOL) UAV which can be utilized as a trade analysis tool in the pre-conceptual design phase. The UAV requires VTOL capability and high speed cruise performance. The main logic of this performance analysis code is to estimate performance parameters of each mission segment by mission fuel weight iteration. The reliability of this performance analysis code is discussed by comparing the data of existing dual flight mode VTOL UAVs such as Boeing CRW and Bell Tilt Rotor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.228-239
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• 2019

In order to design the conceptual configuration of the short-range ballistic missile, the authors have established an optimization problem considering various aspects such as volume, aerodynamics, propulsion, structure, stability, and flight trajectory. For this purpose, the existing missile cases were analyzed and the design conditions and performance indices were derived. The performance of the whole system was analyzed by integrating each subsystem's model. Through the design example, we analyzed the relationship between various design variables and final performances.