This study investigates the feasibility of using acceleration signals to estimate the initial impact location of fragments generated by blast-fragmentation warheads. The experimental setup involved attaching three single-axis accelerometers to a steel plate, spaced 400 mm apart. A preliminary test used hammer strikes to verify the method, while the primary test employed active warheads. For each test, the time difference of arrival(TDOA) was analyzed using the acceleration signals. Trigonometric techniques were used to determine the impact locations, using the group velocity(C_g) calculated based on the wave propagation characteristics. Active warhead results showed that the tests achieved an average location estimation error of less than 10 % in both horizontal and vertical axes, validating the methodology despite the environmental complexities. This demonstrates the potential of using acceleration signals for fragment impact evaluation and highlights avenues for further research.

Aviation Pod mounted on the outside of the aircraft performs surveillance and reconnaissance missions. Therefore, the main structure of the external pod equipment must ensure structural integrity in response to the aircraft's flight missions, and at the same time, the shape of the main equipment must be optimized so as not to impede the flight performance of the aircraft due to excessive weight. In this paper, for the skin of a certain thickness of the main structure, the fatigue life due to acoustic load during flight was calculated and compared for each skin aspect ratio, and the maximum allowable area of the skin was calculated. The calculation and analysis results were reflected in the actual equipment, and an acoustic load test was performed to verify the effectiveness of the structural integrity of the skin.

Rail launchers for air platforms have store locking devices. If excessive force is applied to the launcher beyond the allowable store locking force, the locking device will unintentionally release the store. In order to prevent the inadvertent release, an electromechanical safety locking device(ESLD) is newly applied to the rail launcher. The ESLD includes a structure which supports the end-tip of the detent to prevent the detent from rotating except at the moment of launch. The ESLD prevents detent rotation even if vibration or impact is applied. In this paper, the performance of the ESLD was verified through dynamic analysis and tests. For the analysis, vibration test profile, shock test profile and actual Barrier Arresting Kit pass-through measurement data were used. The analsys was performed by applying these values to the model. For the tests, vibration tests, shock tests and Barrier Arresting Kit pass test were conducted.

This paper compares and analyzes the performance of deep learning-based object detection models for mine detection, particularly Faster R-CNN and YOLOv5, using side-scan sonar images. Additionally, it proposes effective data augmentation method to enhance the generalization performance of mine detection models. Performance evaluation based on the structure and size of each model indicates that the two-stage model, Faster R-CNN, is more suitable for precise search tasks, while the one-stage model, YOLOv5, offers faster processing speed, making it advantageous for rapid mine detection in large maritime areas. This contributes significantly to improving the efficiency of maritime boundary missions and operations utilizing autonomous underwater vehicles, thereby making a substantial impact on naval operations and mine counter measures strategies.

In recent years, significant efforts have been made to address the cost and time challenges associated with satellite-based remote sensing in both civilian and defense sectors by using deep learning-based super-resolution models to enhance satellite imagery. This paper designs and trains a deep learning-based super-resolution model for satellite images. Utilizing high-resolution satellite images generated from the super-resolution model, we produced maps for RPC error correction, point cloud generation, and DSM creation. We validated the effectiveness of these maps by comparing them with maps produced from original satellite images for both outcome and accuracy. Significant results were achieved in RPC error correction, point cloud generation, and DSM creation. Despite increasing the resolution with the super-resolution model, accuracy was either improved or maintained, confirming its validity for map production.

When a ground station is tracking a flight vehicle, flight vehicle's aspect angle with respect to a ground station is required to predict a received signal strength and determine an optimal time to conduct radar handovers. When determining a flight vehicle's aspect angle with respect to a ground station, range/azimuth/elevation coordinate system referenced to a ground station and attitude(roll/pitch/yaw) of a flight vehicle are needed. If tracking range between a ground station and a flight vehicle is sufficiently far, additional compensation for roll and pitch angles should be considered. In this paper, angular compensation method for roll and pitch is proposed in a consideration of earth curvature. And then, flight vehicle's aspect angles with respect to the ground station are obtained and flight vehicle's attitude changes with respect to three ground stations are visualized.

This study aims to optimize the endurance test mode for military vehicles to more closely simulate actual operational conditions. To achieve this, a modified bi-objective optimization approach was developed, combining two system-level objectives for the relative damage of the chassis and powertrain with six corresponding component-level constraints. The modified bi-objective optimization employs the NSGA II(Non-dominated Sorting Genetic Algorithm II) to generate a diverse set of optimal solutions. The results, evaluated using the CRM(Coefficient of Residual Mass) and GMRAE(Geometric Mean Relative Absolute Error) metrics, compare this approach with bi-objective optimization focused solely on system-level objectives and six-objective optimization focused solely on component-level objectives. The findings show that the modified bi-objective approach provides a more accurate and reliable endurance test mode compared to both the bi-objective and six-objective methods.

To obtain fatigue crack closure data, fatigue crack growth tests for AISI 4340 are performed under constant amplitude loading at various stress ratios and the behavior of crack closure is investigated. For determination of crack opening load under constant amplitude loading, ASTM compliance offset method is applied because its simplicity among the various methods. It is observed that crack opening ratios of AISI 4340 for constant amplitude loading are nearly constant at stress ratio R. Based on the characteristic crack closure behavior, Fatigue crack growth rates(da/dN) at various stress ratios are well correlated with effective stress intensity factor range(𝛥K_eff). It was confirmed that the crack closure behavior is the primary factor controlling fatigue crack growth.

In this paper, the damage of a semicircular steel structure specimen simulating a threat when irradiated with a high-energy laser under airflow conditions was analyzed by experiments and numerical analysis. The laser used in this experiment was a CW fiber laser with a wavelength of 1.07 ㎛ and irradiated the specimen within a maximum power of 10 kW. For quantitative analysis of the laser effect, a high-speed camera and a thermal imaging camera were used to acquire the melt-through time and temperature evolution of the specimen, respectively. Along with the experiment, numerical analysis of the experimental conditions was also performed using COMSOL Multiphysics, a commercial code. In addition to the semicircular steel structure, an air domain was added to simulate airflow, and a top-hat shape distribution was applied for beam energy distribution. Two different beam absorption rates were applied to the steel material to compare the temperature distribution of the experimental results, respectively.

Military operations in South Korea require frequent river crossing due to the country's terrain. While existing bridges serve this purpose, it is vulnerable to enemy sabotage. To solve this, the South Korea military introduced ribbon bridges in 1992. However logistical challenges and aging equipments have prompted the need for alternative solutions. The recently introduced Amphibious Bridging Vehicle(ABV) "KM3", developed in Germany's GDELS, offers a promising alternative. This study focuses on estimating the drag resistance of the ABV "KM3" during waterborne operations by using Computational Fluid Dynamics(CFD). Since discretization errors in time and space are critical error factors in CFD analysis, 'Grid convergence Index' was applied to study the reduction of these errors. Based on this, the hydrodynamic performance of ABV "KM3" was evaluated under varying flow velocities.

This study focuses on improving fault tolerance performance of Guided Weapon Fire Control Unit(FCU) based on decentralizing fire control and improved redundancy. The hot standby redundant FCU converts the spare module into a service module when a service module malfunctions. In the improved system, uninterrupted launch is possible even when above transition occurs because fire sequence control was transferred from FCU to separate Missile Control Unit(MCU), and an additional message recovery process was designed to compensate for the loss of message transmission during the transition time. Through experiments, the fault tolerance performance of the FCU was verified by measuring the role switching performance and message recovery performance.

Multi-robot systems have advantages of higher scalability and flexibility compared to high-cost single robot. Due to these advantages, the utilization of multi-robots in various fields are increasing. One of the example is exploration problem of unknown mission area, where multi-robot system have better accessibility to narrow space, and ability to respond to potential risks like hidden enemy. When multi-robot systems are used for exploration, it is necessary to consider cooperation of robots to achieve satisfactory performance of the overall system. In this paper, an frontier and task allocation-based cooperative exploration algorithm for multi-robot system is suggested. Multi-robots are organized into serveral groups with hierarchy. Frontier segmentation and clustering approach was utilized to consider cooperation between groups and individual robots. Numerical simulations are conducted to verify performance of the algorithm, and the suggested algorithm showed appropriate performance compared to the centralized method.

This paper studies optimizing supply routes to resupply points using future battlefield transport systems such as UGVs and drones, along with existing transport vehicles. Drones, being unmanned systems, offer high mobility but have limited payload capacity, while UGVs provide greater payload capacity but lower mobility. Transport vehicles offer very high payload capacity but significantly less mobility, and as manned systems, they can supply areas inaccessible to unmanned systems. Moreover, actual battlefields may present situations where certain transport systems cannot enter due to enemy threats, road destruction, electronic attacks, and other factors. Therefore, this study designs routes that minimize transportation time during supply operations by considering realistic constraints that may occur in future battlefields and reflecting the characteristics of each transport system. Additionally, we propose a genetic algorithm to demonstrate that large-scale problems can be solved within limited time during urgent wartime conditions.

This study analyzed the penetration performance characteristics of activated carbon-based CBRN protective clothing before and after washing. Experiments were conducted applying various washing conditions, including types of washing machines, washing mode, and detergents. The penetration performance after washing was evaluated through adsorption and penetration tests using simulated chemical agents and chemical warfare agents(CWAs). The results indicated that penetration performance was more significantly affected by detergents than by the type of washing machine or washing mode, with the surfactant content in detergents being the most crucial factor. This research revealed that detergent selection is the key to maintain penetration performance when establishing washing procedures for CBRN protective clothing. This study is expected to contribute to the standardization of washing procedures for activated carbon-based CBRN protective clothing in the future.