• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.9
• /
• pp.897-904
• /
• 2017

Optical equipment consists of various components, and a detector is mounted and operated on aircraft, tanks, and warships for target detection and classification. The structural stability and optical performance of aeronautical optical equipment operated at several kilometers of altitude are degraded owing to vibration generated in the aircraft. It is necessary to verify the structural stability and optical performance requirements of the equipment in vibration environment conditions during the design phase. In this study, vibration environment conditions were analyzed using a test standard and the measurements of the vibration generated in aircraft. The conditions were classified as endurance and operating vibration conditions for structural stability and optical performance verification, respectively. The structural stability was verified according to natural frequency analysis, response analysis for the endurance vibration condition, and static analysis. The optical performance was verified by applying the vibration response analysis results to the optical design/analysis program.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.3
• /
• pp.497-502
• /
• 2020

For the Navy to acquire the desired vessels in time, it is necessary to plan the schedule accurately for warships. On the other hand, until now, there has been only a subjective prediction of the period of warship construction through a survey by a group of experts. No academic studies have been conducted based on actual data. Therefore, this study presents a model for predicting the construction period of a warship through linear regression based on actual data. Experts first identified the factors that can affect the warship construction period. Actual data of the factors were collected, and regression analysis was performed to estimate the ship construction period. As a result, the key factors selected that influence the construction period of a ship were the number of operational test items, number and type of equipment, and the number and type of R&D equipment. The resulting regression model revealed 96.5% accuracy in terms of internal validity.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.4
• /
• pp.468-472
• /
• 2015

Recently, there has been increasing interest in the efficient use of energy due to policies related to the reduction of greenhouse gas. This paper suggests a highly efficient sea water cooling system for the load-dependent control of a seawater pump depending on the load, to improve energy efficiency of the warship. This study models the propulsion diesel engine and simulation reflecting the characteristics of the warship operation state that checked the performance of high efficiency sea water cooling system. The simulation results revealed the cooling system of high efficiency with energy savings of approximately 53% compared to the existing cooling systems. These results can be used to improve the performance of the cooling system of the warship propulsion diesel engine in the future.

• Journal of the Korea Society for Simulation
• /
• v.20 no.3
• /
• pp.79-88
• /
• 2011

In most existing warships combat simulation system, the tactics of a warship is manipulated by human operators. For this reason, the simulation results are restricted due to the stereotype of human operators. To deal with this, we have employed the genetic algorithm for supporting the evolutionary simulation environment. In which, the tactical decision by human operators is replaced by the human model with a rule-based chromosome for representing tactics so that the population of simulations are created and hundreds of simulation runs are continued on the basis of the genetic algorithm without any human intervention until to find emergent tactics which shows the best performance throughout the simulation. This paper proposes an evolutionary tactics generation methodology for the emergent tactics in many-to-many warship combat simulation. To do this, 3:3 warship combat simulation tests are performed.

• Journal of Navigation and Port Research
• /
• v.37 no.2
• /
• pp.149-154
• /
• 2013

This paper considers the issue of LSS(Liquid Spill Stopper)'s performance verification testing against external resisting force. The importance of the test is to ascertain the possibility of liquid spill stop quickly and efficiently by LSS. The method adopted in this research is the experimental device for puncture's inflow pressure and test the adhesive (magnetic) force on shell plates during the sailing. The major results of the paper are the followings : (a) The performance of LSS against 40 and 100mm diameter puncture was confirmed under 1.0bar. (b) LSS near bow detached first at 20.2 knots. This indicates that LSS can recover the damaged movability needed to naval warships' operation as well as merchant ships.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.8
• /
• pp.558-565
• /
• 2019

A lot of studies on the survivability of missiles have been widely studied, since the technology of modern warships equipped with state-of-the-art defense systems has been improved. The survivability of missiles can be improved by attacking a target simultaneously using multiple missiles. For this reason, impact time control guidance (ITCG) laws have been widely studied. This paper deals with the effect of time-to-go estimate to ITCG laws. In this paper, two kinds of time-to-go estimate are first introduced in two-dimensional and three-dimensional environment and then ITCG laws are derived using the time-to-go estimate. Numerical simulations are performed to analyze the performance of the designed ITCG laws and the effect of time-to-go estimate is discussed.

• Journal of the Korea Society for Simulation
• /
• v.28 no.1
• /
• pp.67-79
• /
• 2019

A warship equipped with Multi Function Radar(MFR) performs operations by evaluating the degree of threats based on threats' symptom and allocating the resource of MFR to the corresponding threats. This study suggests a simulation-based approach and greedy algorithm in order to effectively allocate the resource of an MFR for warships, and compares these two approaches. As a detection probability function depending on the amount of allocations to each threat, we consider linear and exponential functions. Experimental results show that both the simulation-based approach and greedy algorithm allocate resource similarly to the randomly generated threats, and the greedy algorithm outperforms the simulation-based approach in terms of computational perspective. For a various cases of threats, we analyze the results of MFR resource allocation using the greedy algorithm.

• Maritime Security
• /
• v.1 no.1
• /
• pp.61-92
• /
• 2020

This paper attempts to examine the changes in China's naval strategy and to analyze the goal, range, and method of each strategy during the Xi Jinping's era. Since the founding of New China, the People's Liberation of Army Navy(PLAN) has made four changes in the naval strategy. Under Xi Jinping's administration, China's naval strategy is far seas operation combined with near seas active defense. Now, China's naval strateg y is shifting from a defensive to an aggressive one, increasing the proportion of offensive weapon systems and the number of state-of-the-art warships, and the scope of the naval strategy has been specified in the second island chain including the Indian Ocean. With the changes of naval strategy, the PLAN will set a new strategic goal to secure maritime dominance and implement an assertive strategy to actively respond to the intervention and intrusion of external forces. Moreover, the PLAN will also improve its sea-based deterrence force and the maneuver force to block other countries in the long-distance maritime conflict zones. The operation method of China's future naval strateg y will gradually shift from 'interdiction' to 'rapid-response.'

• Journal of the Korean Society of Systems Engineering
• /
• v.18 no.2
• /
• pp.108-116
• /
• 2022

Accurately predicting wartime resources requirements and preparing war supplies in peacetime is an important task that can determine the outcome of the war by guaranteeing the duration of the operation. The wartime warship damage rate is a measure of estimating the battle damage of our warships in the process of performing battles to achieve the war goal. In the previously studied wartime warship damage rate estimation method, when damage occurs, long-term repair is required due to the complexity and specificity of the ship structure. Only the case of a complete defeat at the level of sinking was defined as a damage, and even if it was impossible to perform a maritime operation mission, it was not estimated as a damage if the level of sinking was not reached. Therefore, in order to improve the reliability of the wartime warship damage rate, the equipment damage assessment level can be estimated based on the warhead weight of the threat weapon system, the vulnerability rate of the warship's equipment, and the warship's hull. In the future, it is expected that the estimation methodology proposed in this study will be used as a simulation logic when developing a model for analyzing the wartime resources requirements for the warship's equipment and hull.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.194-196
• /
• 2022

When electromagnetic wave transmitted from the radar antenna hits the target, a specific type of electric field is formed according to the electrical characteristics and appearance of the target, which is called an RCS pattern. There are various commercial programs that calculate the RCS of the target and plot the RCS pattern. For the analysis of large targets such as warships or ships, a program with a high frequency analysis method, which has a faster calculation speed than the low frequency analysis method is suitable. XGTD, a high-frequency analysis program, can quickly plot a two-dimensional RCS pattern for 360 degrees of a target, but a three-dimensional RCS pattern cannot be obtained. In this paper, it is proposed that a method of plotting two-dimensional RCS patterns of a target from various angles using XGTD, generating a three-dimensional RCS pattern using this, and converting it into a three-dimensional antenna pattern file.