• Journal of Aerospace System Engineering
• /
• v.15 no.1
• /
• pp.63-71
• /
• 2021

The South Korean Navy has operated Harpoon guided missiles through step-by-step acquisition after adopting them for the first time in 1978. As Harpoon guided missiles have been operated for a long time, it is necessary to make an active follow-up logistics support to guarantee their performance. Inspection of guided missiles is a basic activity to check the status of missiles. This study was conducted to check if the existing inspection interval of Harpoon guided missiles that have been operated for a long time was appropriate. Regarding research methods, based on the Navy's field operation materials, this study analyzed and presented inspection interval by section according to the period of operation, utilizing the Martinez's theory and a non-parametric MCF technique.

• Journal of Space Technology and Applications
• /
• v.2 no.2
• /
• pp.67-80
• /
• 2022

The missile early-warning satellite systems have been developed and upgraded by some space-developed nations, under the inevitable trend that the space is more strongly considered as another battle field than before. As the key function of such a satellite-based early warning system, the prediction algorithm of the missile flight trajectory is studied in the paper. In particular, the evolution computation, receiving broad attention in the artificial intelligence area, is applied to the proposed prediction method so that the global optimum-like solution is found avoiding disadvantage of the previous non-linear optimization search tools. Moreover, using the prediction simulator of the launch vehicle flight trajectory which is newly developed in C# and Python, the paper verifies the performance and the feature of the proposed algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.2
• /
• pp.54-59
• /
• 2005

Nonlinear aeroelastic analyses of a missile control fin are performed considering backlash and dynamic stiffness of actuator. Doublet-Hybrid method is used for the calculation of subsonic unsteady aerodynamic forces, and aerodynamic forces are approximated by the minimum-state approximation. For nonlinear flutter analysis backlash is represented by a free-play and is linearized by using the describing function method. Also, dynamic stiffness is function of frequency and is calculated by solving equation of motion for actuator. The linear and nonlinear flutter analyses show that the aeroelastic characteristics are significantly dependent on the backlash and dynamic stiffness. From the nonlinear flutter analysis, various types of limit cycle oscillations are observed in a range of air speeds below the linear divergent flutter boundary. The nonlinear flutter characteristics and the nonlinear aeroelastic responses are also investigated in the time domain.

• Journal of the Korea Society for Simulation
• /
• v.25 no.1
• /
• pp.1-9
• /
• 2016

This study focuses on the air to air missile control fin planform optimization for the minimizing hinge moment with the considering phenomena of fluid and structure simultaneously. The fluid-structure interaction method is applied for the fluid and structure phenomena simulation of the control fins. A transient-loosely coupled method is used for the fluid-structure interaction simulation because it is suited for using each fluid and structure dedicated simulation software. Searching global optimization point is required many re-calculation therefore in this study, a mathematical model is applied for rapidly calculation. The face centered central composite method is used for generating design points and the 2nd polynomial response surface is sued for generating mathematical model. Global optimization is performed by using the generic algorithm. An objective function is the minimizing travel distance of the center of pressure between Mach 0.7 and 2.0 condition. Finally, the objective function of optimized planform is reduced 7.5% than the baseline planform with satisfying constrained conditions.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.23 no.5
• /
• pp.452-458
• /
• 2020

In this paper, the contents of the development of RESS(Radar Environmental Signals Simulator) for the test of active phased array multi-function radar are described. The developed RESS can simulate multiple target environments, such as target/jamming/missile response/cluster signals, by using received radar operational information and simulated scenario. It can also modulate frequency, phase, gain, timing on all waveforms operated by multi-function radar and simulated two targets and one jamming in the beam. The RESS can be used to perform functional and performance verification of the active phased array multi-function radar with sub-array receiving structures.

• Journal of Pharmacopuncture
• /
• v.14 no.2
• /
• pp.75-80
• /
• 2011

Objectives & Methods: This research may accounts for Self Targeting Therapy (STT) which is a peculiar operation of Mountain Ginseng Pharmacopuncture. The objectives include analysis of its mechanism and reporting of clinical cases. Results: 1. STT of Mountain Ginseng Pharmacopuncture refers to the function of curing and making a diagnosis of the disease by oneself. 2. The mechanism of STT is to pursue the latent illness and make the remedial action by oneself. In this process, the symptom of latent disease is outwardly expressed. 3. The most popular symptom expressed is manifestation of pecular sensation along the specific meridians. Then followed headache, dizziness, powerless and etc. Diverse symptoms can be expressed by a patient. 4. If the revealed symptoms are carefully observed, the cause of the disease or the patient state can be diagnosed easily. Conclusion: The mechanism of STT of Mountain Ginseng Pharmacopuncture can be a great asset in clinical trials. Other studies on STT of Mountain Ginseng Pharmacopuncture should be followed in the future.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.199-199
• /
• 2000

Most of linear time-varying(LTV) systems except special cases have no general solution for the dynamic equations. Thus, it is difficult to design time-varying controllers in analytic ways, and other control design approaches such as robust control have been applied to control design for uncertain LTI systems which are the approximation of LTV systems have been generally used instead. A robust control method such as quantitative feedback theory(QFT) has an advantage of guaranteeing the stability and the performance specification against plant parameter uncertainties in frozen time sense. However, if these methods are applied to the approximated linear time-invariant(LTI) plants which have large uncertainty, the designed control will be constructed in complicated forms and usually not suitable for fast dynamic performance. In this paper, as a method to enhance the fast dynamic performance, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks for LTV systems with bounded time-varying parameters.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.2
• /
• pp.97-107
• /
• 2002

The continuous circular cylindrical shells are widely used for the high performance structures of aircraft, spacecraft, missile, nuclear fuel rod shell and so on. In this paper, a method for the vibrational analysis of the continuous circular cylindrical shells with the clamped-clamped supports at two end edges is developed by using the modal expansion method. Forces and/or moments acting on the shell surface are expressed in terms of the Dirac Delta Function. Frequency equation of the continuous shell is also derided by the application of the equilibrium of forces and the continuity of displacements at the boundary. Natural frequencies of the continuous shell are calculated numerically with mathematica 3.0 and they are compared with FEM results from the ANSYS 5.3 to improve the reliability of analytic solutions. Mode shares obtained by the FEM are Presented in this paper.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.19 no.3
• /
• pp.289-303
• /
• 2015

In this paper, an optimal guidance law with terminal angle constraint considering the seeker's lock-on condition, in which the target is located within the field-of-view (FOV) and detection range limits at the end of the midcourse phase, is proposed. The optimal solution is obtained by solving an optimal control problem minimizing the energy cost function weighted by a power of range-to-go subject to the terminal constraints, which can shape the guidance commands and the missile trajectories adjusting guidance gains of the weighting function. The proposed guidance law can be applied to both of the midcourse and terminal phases by setting the desired relative range and look angle to the final interception conditions. The performance of the proposed guidance law is analyzed through nonlinear simulations for various engagement conditions.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.64.1-64.1
• /
• 2013

The point spread function (PSF) of an optical system is in general defined as a two-dimensional intensity distribution which results from a single point source at infinity. It is an important key for the evaluation of the optical performance of an astronomical telescope. The PSFs of the soft X-ray telescope (SXT) aboard Yohkoh were measured in a wide range of the field-of-view under the in-flight configuration at White Sands Missile Range prior to launching the satellite. It has been known that the SXT PSF has a sharp peak at the core and the intensity drops very fast as it goes distant from the center. Due to the combination of this sharp peak at the PSF core and the effect of undersampling by a large pixel size, a carefully designed method is requested in the examination of the PSF data. The pattern of the SXT PSF is determined by the fitting of a mathematical functional form to the pre-launch experimental data. The elliptical Moffat function has been adopted for the evaluation of the SXT PSF. It is revealed from our study that the SXT PSF shows a peculiar characteristics, and thus a careful consideration on the undersampling effect and also a proper choice of statistics are necessary for the determination of the best fit function of the PSF. Details on the on- and off-axis SXT PSF in the field-of-view will be introduced and discussed in our presentation.