• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.281-289
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• 2016

Accurate prediction of the trajectory and time of a time-varying mass parachute system remains essential in the mission requiring a precision airdrop to the ground. In this study, we investigate the altitude-varying behavior of a cross-type parachute system designed to deliver a time-varying mass object like flare. The dynamics of the descending parachute system was analyzed based on the Runge-Kutta method of the ordinary differential system. The drag coefficients of the cross-type parachute and flare were calculated by a CFD code based on the incompressible Navier-Stokes equation. Finally, by using a simplified gust wind model in troposphere, the combined effects of gust wind and time-varying mass were examined in detail.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.6
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• pp.465-472
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• 2013

In this paper, we suggest how to determine the parachute deploy position for accurate landing of a UAV at a desired position. The 9-DOF dynamic modeling of UAV-parachute system is required to construct the proposed algorithm based on neural network nonlinear function approximation technique. The input and output data sets to train the neural network are obtained from simulation results using UAV-parachute 9-DOF model. The input data consist of the deploy position, UAV's velocity, and wind velocity. The output data consist of the cross range and down range of landing positions. So we predict the relative landing position from the current UAV position. The deploy position is then determined through distance compensations for the relative landing positions from the desired landing position. The deploy position is consistently calculated and updated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.8
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• pp.726-736
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• 2012

This paper deals with Spin/Stall Recovery Parachute System from design to ground taxiing stage which would be deployed on the high speed taxi of turbo-prop airplane. In detail design phase, design parameters- riser length, parachute type, size, porosity, parachute canopy filling time, and deployment method- were considered based on the analytical disciplines such as aerodynamics, structures, and stability & control. Before the installation of Spin/Stall Recovery System of turbo-prop airplane, all control functions of this system were validated by the SBTB(System Breakout Test Box) in the laboratory. SBTB was used to confirm if it can detect faults, and simulate the firing of pyrotechnic devices that control the deployment and jettison of it. Once confirmed normal operation, deployment of parachute on the high speed taxiing were performed.

• Journal of Aerospace System Engineering
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• v.10 no.2
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• pp.22-26
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• 2016

Whole airplane recovery parachute system(WARPS) is a auxiliary safety system to protect occupants in emergency situation where recovery to normal flight condition is impossible. In this paper, application and certification cases of WARPS for Part 23 small airplane is introduced and considerations in certification of the WARPS installed airplane are provided in terms of performance of parachute, function and operation, loads and strength and protection of occupants.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.77-87
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• 2022

The Precision Aerial Delivery System is an instrument designed to improve the poor landing accuracy of aerial delivery system with conventional circular parachutes, and is equipped with an Airborne Guidance Unit to safely transport supplies to the desired destination. Currently, the landing accuracy of the PADS product is reported as CEP₅₀ 100m and also differs significantly, depending on the actual topography and weather environment. In this study, HILS was constructed based on the 6DOF nonlinear modeling of PADS to analyze the maneuver characteristics of Ram Air Parachute under wind environments. By using the new algorithm a precision soft landing algorithm including Energy Management and Final Approach is designed. HILS results show that it is possible to achieve a precise soft landing within CEP₅₀ 40m, and it can be exploited to develop an actual PADS drop test.

• Korean Business Review
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• v.22 no.1
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• pp.1-25
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• 2009

Typically, economic rationality is too apart from in a public enterprises system is started many cause troubles. The government in that upper management personnel of agencies and politicians who exploit the parachute and coalesce with the labor union as a hotbed of corruption due to inefficiency have bands. Most of peoples need to reform public enterprises and the idea became. The future direction of public enterprise reform is clear. As like Infrastructure industrial sector which is difficult to privatization of government owned and controlled public enterprises to improve efficiency and management systems to build. On the other hand, it is difficult to upset non-public enterprises, private sector efficiency in the transfer of management control to consider the idea of an active policy of privatization conversion is required.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.231-239
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• 2022

The labor director system to be introduced into the company law, the labor director must be explained in the Korean company law and the inevitability of its introduction must be persuaded. Conflicts with shareholders' right to appoint institutions are also a task that must be resolved. Management has absolute meaning for shareholders who receive dividends from operating profit. On the other hand, for workers who are guaranteed the right to collective action and are paid for their labor according to the contract law and the labor law, the management must be considered as a partner in labor-management cooperation, so the labor director system may cause confusion. There are growing calls to create a system that can form a 'relationship of understanding, participation, and cooperation', away from the existing 'control and command'-centered manpower management that causes labor-management confrontation and the system can also serve as an opportunity to reduce harmful effects of high-handed personnel administration in public institutions.