• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.156.2-156
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• 2001

Hypersonic civil airplanes are recently heated up again in USA and Japan, but there are several difficulties when we obtain its optimal trajectories. In this paper, we formulated the trajectory optimization problem as an optimal control problem and solved it by the direct shooting method with the Genetic Algorithm, GA. The result shows it is effective to use this method for the trajectory optimization of the hypersonic flight.

• Structural Engineering and Mechanics
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• v.4 no.1
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• pp.49-59
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• 1996

This paper considers large deflection problem of a simply supported beam with variable are length subjected to a point load. The beam has one of its ends hinged and at a fixed distance from this end propped by a frictionless support over which the beam can slide freely. This highly nonlinear flexural problem is solved by elliptic-integral method and shooting-optimization technique, thereby providing independent checks on the new solutions. Because the beam can slide freely over the frictionless support, there is a maximum or critical load which the beam can carry and it is dependent on the position of the load. Interestingly, two possible equilibrium configurations can be obtained for a given load magnitude which is less than the critical value. The maximum arc-length was found to be equal to about 2.19 times the fixed distance between the supports and this value is independent of the load position.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.379-386
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• 2015

This work presents fuel-optimal altitude maintenance of Low-Earth-Orbit (LEO) spacecrafts experiencing non-negligible air drag and J2 perturbation. A pseudospectral (direct) method is first applied to roughly estimate an optimal fuel consumption strategy, which is employed as an initial guess to precisely determine itself. Based on the physical specifications of KOrea Multi-Purpose SATellite-2 (KOMPSAT-2), a Korean artificial satellite, numerical simulations show that a satellite ascends with full thrust at the early stage of the maneuver period and then descends with null thrust. While the thrust profile is presumably bang-off, it is difficult to precisely determine the switching time by using a pseudospectral method only. This is expected, since the optimal switching epoch does not coincide with one of the collocation points prescribed by the pseudospectral method, in general. As an attempt to precisely determine the switching time and the associated optimal thrust history, a shooting (indirect) method is then employed with the initial guess being obtained through the pseudospectral method. This hybrid process allows the determination of the optimal fuel consumption for LEO spacecrafts and their thrust profiles efficiently and precisely.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.56-65
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• 2014

Contamination of explosive compounds in the soils of military shooting range may pose risks to human and ecosystems. As shooting ranges are located at remote places, active remediation processes with hardwares and equipments are less practical to implement than natural solutions such as bioremediaton. In this study, a series of experiments was conducted to select a suitable carbon source and to optimize dosing rate for the enhanced bioremediation of explosive compounds in surface soils and sediments of shooting ranges with indigenous microorganisms activated by external carbon source. Treatability study using slurry phase reactors showed that the presence of indigenous microbial community capable of explosive compounds degradation in the shooting range soils, and starch was a more effective carbon source than glucose and acetic acid in the removal of TNT. However, at higher starch/soil ratio, i.e., 2.0, the acute toxicity of the liquid phase increased possibly due to transformation products of TNT. RDX degradation by indigenous microorganisms was also stimulated by the addition of starch but the acute toxicity of the liquid phase decreased with the increase of starch/soil ratio. Taken together, the optimum range of starch/soil ratio for the degradation of explosive compounds without significant increase in acute toxicity was found to be 0.2 of starch/soil.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.1
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• pp.19-25
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• 2024

This paper proposes an artificial intelligence-based personal information area object detection optimization method in an embedded system to de-identify personal information in video data. As an object detection optimization method, first, in order to increase the detection rate for personal information areas when detecting objects, a gyro sensor is used to collect the shooting angle of the image data when acquiring the image, and the image data is converted into a horizontal image through the collected shooting angle. Based on this, each learning model was created according to changes in the size of the image resolution of the learning data and changes in the learning method of the learning engine, and the effectiveness of the optimal learning model was selected and evaluated through an experimental method. As a de-identification method, a shuffling-based masking method was used, and double-key-based encryption of the masking information was used to prevent restoration by others. In order to reuse the original image, the original image could be restored through a security key. Through this, we were able to secure security for high personal information areas and improve usability through original image restoration. The research results of this paper are expected to contribute to industrial use of data without personal information leakage and to reducing the cost of personal information protection in industrial fields using video through de-identification of personal information areas included in video data.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.441-453
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• 2017

In this paper, a new type of weapon-target assignment(WTA) problem has been suggested that reflects realistic constraints for sharing target with other weapons and shooting double rapid fire. To utilize in rapidly changing actual battle field, the computation time is of great importance. Several metaheuristic methods such as Simulated Annealing, Tabu Search, Genetic Algorithm, Ant Colony Optimization, and Particle Swarm Optimization have been applied to the real-time WTA in order to find a near optimal solution. A case study with a large number of targets in consideration of the practical cases has been analyzed by the objective value of each algorithm.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.148-154
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• 2018

When shooting small arms, the inner surface temperature is heated up to about $700{\sim}1,000^{\circ}C$ by the friction of the bullet and the inner wall of the barrel and the combustion of propellant. High-temperature propellant gas and high-speed movement of the bullet cause corrosion of the inner wall, which is noticeable immediately in front of the chamber. In this study, the mechanical properties of Cr-Mo-V steel, which is the base material, were tested using Taguchi experimental design to find the best nitriding treatment conditions. For the nitriding process, the working time, salt bath temperature, and salt concentration were combined as three conditions and placed in the $L_9(3^4)$, orthogonal array table. The thicknesses of the white layer and the nitrogen diffusion layer were measured after nitriding under each condition in a salt bath furnace. Durability was evaluated by measuring the degree of dispersion through actual shooting because it was difficult to evaluate the mechanical properties of the cylinder inner structure. As a result, it was confirmed that the durability was optimal at $565^{\circ}C$, 1 hour, 0.5%. These optimal conditions were selected by the statistical analysis of the Minitab program(ver.17).

• Economic and Environmental Geology
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• v.42 no.5
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• pp.457-469
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• 2009

Applicability of bioleaching techniques using a sulfur-oxidizing bacteria, Acidithiobacillus thiooxidans, for remediation of shooting range soil contaminated with toxic heavy metals was investigated. The effects of sulfur concentration, the amount of bacterial inoculum and operation temperature on the efficiency of heavy metal solubilization were examined as well. As sulfur concentration and the amount of bacterial inoculum increased, the solubilization efficiency slightly increased; however, significant decrease of heavy metal extraction was observed with no addition of sulfur or bacterial inoculum. Bacteria solubilized the higher amount of heavy metals at $26^{\circ}C$ than $4^{\circ}C$. Lead showed the highest removal amount from the contaminated soil but the lowest removal efficiency when compared with Zn, Cu and Cr. It was likely due to formation of insoluble $PbSO_{4(s)}$ as precipitate or colloidal suspension. Sequential extraction of the microbially treated soil revealed that the proportion of readily extractable phases of Zn, Cu and Cr increased by bacterial leaching, and thus additional treatment or optimization of operation conditions such as leaching time were required for safe reuse of the soil. Bioleaching appeared to be a useful strategy for remediation of shooting range soil contaminated with heavy metals, and various operating conditions including concentration of sulfur input, inoculum volume of bacteria, and operation temperature exerted significant influence on bioleaching efficiency.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1063-1071
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• 2023

Unmanned aerial vehicles (UAVs, drones) are becoming increasingly useful in a variety of fields. Advances in UAV and camera technology have made it possible to equip them with ultra-high resolution sensors and capture images at low altitudes, which has improved the reliability and classification accuracy of object identification on the ground. The distinctive contribution of this study is the derivation of sensor-specific performance metrics (GRD/GSD), which shows that as the GSD increases with altitude, the GRD value also increases. In this study, we identified the characteristics of various onboard sensors and analysed the image quality (discrimination resolution) of aerial photography results using UAVs, and calculated the shooting conditions to obtain the discrimination resolution required for reading ground objects.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.175-176
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• 2008

향후 개발되어질 Digital Power IED (Protection & Measuring, Control, Supervision etc.) 에서 제작된 H/W 및 Simulation용 Target Board 의 Firmware Process Flow 지침으로서 개발 경험을 바탕으로 보다 안정적이고 효율적인 Programming 을 가능하게 하고, 실시간 연산 Process 의 기준 확립 및 이해를 통한, 개선 아이디어 도출 및 수정 필요시 빠른 Trouble-Shooting 능력을 배양할 수 있다. 새로운 Process 아이디어의 Simulation 적용 및 확인으로 호환성과 안정성에 기반하는 F/W Optimization을 항상 유지 관리할 수 있으며, Measuring Element (전압, 전류, 전력, 주파수 등), Protection Element (OC, OCG, OV, OVG, UV, UC, DOC 등) 의 기준을 정함으로서 새로운 개발자에게는 개발 실무를 위한 교육 자료로 이용하고, 기존 개발자들에게는 안정된 F/W 모듈을 제공한다. 본 논문에서는 개발 시간을 단축하고, 다양한 진보 Process 접근을 원활히 할 수 있는 F/W 및 S/W 시뮬레이터를 제시한다.