• Journal of the Korean Society of Systems Engineering
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• v.6 no.1
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• pp.33-39
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• 2010

Anti-surface missiles have been the most dangerous threat to the surface ships, therefore analyzing the defense effectiveness of surface ships against diverse anti-surface missiles attack strategies is very important to evaluate and anticipate the naval combat ship's abilities in terms of AAW (Anti-Air Warfare). In this paper, we don't study on the defense effectiveness of a ship against a missile, but focus on the defense effectiveness for surface ships against multiple missiles specialized in strategies of anti-surface missiles; ripple fire attack and simultaneous time on target attack (STOT). So, we conduct a variety of monte-carlo simulations with high-fidelity simulators, analyze the measure of defense effectiveness for the key factors of strategies and evaluate the effects and possible interactions of several factors through the analysis of the design of experiment (DOE).

• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.53-64
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• 2021

Wargame is a simulated military operation with certain rules, specifications, and procedures, in which soldiers can virtually and indirectly experience the war. The ROK Navy operates the Cheonghae model, a training wargame model for helping commanders and staff master the procedures for conducting the war. It is important for commanders, staff and analysts to know whether a warship can perform its missions and how long it can last during a war. In existing model, the Cheonghae, the probability of kill of a warship is calculated simply considering the number of tonnage without any stochastic elements, and the warship's mission availability is also determined based on predetermined values. With this model, it is difficult to get a value of the probability of kill that makes sense. In this dissertation, the author has developed a probabilistic model in which the warship vulnerability data of ROK-JMEM can be used. A conceptual model and methodology that can evaluate the mission performance of personnel, equipment, and supplies has been proposed. This can be expanded to a comprehensive assessment of wartime warship loss rates by integrating damage rates for personnel, equipment, and supplies in wartime.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.194-202
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• 2019

Reliability analysis of the components frequently starts with the data that manufacturer provides. If enough failure data are collected from the field operations, the reliability should be recomputed and updated on the basis of the field failure data. However, when the failure time record for a component contains only a few observations, all statistical methodologies are limited. In this case, where the failure records for multiple number of identical components are available, a valid alternative is combining all the data from each component into one data set with enough sample size and utilizing the useful information in the censored data. The ROK Navy has been operating multiple Patrol Killer Guided missiles (PKGs) for several years. The Korea Multi-Function Control Console (KMFCC) is one of key components in PKG combat system. The maintenance record for the KMFCC contains less than ten failure observations and a censored datum. This paper proposes a Bayesian approach with a Dirichlet mixture model to estimate failure time density for KMFCC. Trends test for each component record indicated that null hypothesis, that failure occurrence is renewal process, is not rejected. Since the KMFCCs have been functioning under different operating environment, the failure time distribution may be a composition of a number of unknown distributions, i.e. a mixture distribution, rather than a single distribution. The Dirichlet mixture model was coded as probabilistic programming in Python using PyMC3. Then Markov Chain Monte Carlo (MCMC) sampling technique employed in PyMC3 probabilistically estimated the parameters' posterior distribution through the Dirichlet mixture model. The simulation results revealed that the mixture models provide superior fits to the combined data set over single models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.409-414
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• 2021

Tightness performance that blocks compartments is important for surface ships to achieve superior mission performance and survivability in combat environments. To meet the above requirements, airtightness of the structural elements and the appropriate strength to specific areas are checked during a test run after ship construction. In particular, air tests of compartments adjacent to the water surface are performed. In an air test, air is injected into the compartment up to the test pressure of the test memo. The pressure drop value is checked after 10 minutes to determine if the requirements of the corresponding area are satisfied. In summer, however, when the influence of the outside temperature is large, a phenomenon in which the internal pressure increases during the air test was identified. This phenomenon reduces the reliability of the test result. Therefore, a system was designed to compensate for temperature changes in the compartments through this study. The developed system calculates the amount of pressure change caused by a temperature change in the compartment and outputs a correction value. The pressure change was calculated using the ideal gas equation, reflecting the maintenance, increase, and decrease in temperature during the test process. A comparison of the calculated pressure correction value with the database of NIST REFPROP revealed a difference of 0.126% to a maximum of 0.253%.

• Strategy21
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• s.44
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• pp.28-53
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• 2018

The U.S. has recently developed Free and Open Indo-Pacific strategy and Distributed Lethality strategy based on a common perception that they are responding to China's threats. In the future, it is anticipated the following. Strengthen cooperation of the U.S.-India-Vietnam navy, Maximizing the combined combat power between the U.S. and regional navies, Improving its ability to restore damage control, Economic cooperation between the Pacific and Indian countries. The meanings given to the Korean navy are as follows. First, South Korea should pursue cooperation with the Indian Navy, which will grow into a regional balance on China's growth. The growth of the Indian navy is expected to increase cooperation with other Pacific countries. The government should seek ways to promote cooperation with india navy in various fields. Secondly, it is a joint drill between the U.S. Navy and the Korean Navy. Recently, the Korea-U.S. joint drill has not been conducted and many changes are expected to be made regarding the implementation of the joint drill in the future. Therefore, it is necessary to respond to possible changes in the naval relationship between Korea navy and the U.S. navy Also, due to distributed lethality strategy, preparations for operations and training with U.S.navy will be necessary. Lastly, it should contribute to cooperation among regional countries in preparation for maritime territorial disputes. The growth of the Chinese navy and the territorial disputes in the East and South China sea has raised the possibility of accidental military clashes at sea. Therefore, the government should make efforts to create multilateral security cooperation systems that can continue to promote the prevention of armed conflict.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.148-155
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• 2015

The Levenberg-Marquardt method is a well known solution about the least square problem. However, in a Target Motion Analysis(TMA) application most of researches have used the Gauss-Newton method as a batch estimator, which of inverse matrix calculation may causes instability problem. In this paper, Levenberg-Marquardt method is applied to TMA problem to prevent its divergence. In experiment, its performance is compared with Gauss-Newton in domain of range, course and speed. Monte Carlo simulation reveals the convergence time and reliability of the TMA based on Levenberg-Marquardt.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.96-107
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• 2014

Tracking the tactical object is a fundamental affair in network-equipped modern warfare. Geodetic coordinate system based on longitude, latitude, and height is suitable to represent the location of tactical objects considering multi platform data fusion. The motion of tactical object described as a dynamic model requires an appropriate filtering to overcome the system and measurement noise in acquiring information from multiple sensors. This paper introduces the filter suitable for multi-sensor data fusion and tactical object tracking, particularly the unscented transform(UT) and its detail. The UT in Unscented Kalman Filter(UKF) uses a few samples to estimate nonlinear-propagated statistic parameters, and UT has better performance and complexity than the conventional linearization method. We show the effects of UT-based filtering via simulation considering practical tactical object tracking scenario.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5827-5833
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• 2013

Due to science and technology evolutions, modern systems are becoming larger and more complex. In developing complex systems, Model-Based Systems Engineering (MBSE), which is approach to reduce complexity, is being introduced and applied to various system domains. However, because of the modeling being made through a variety of languages, there is a problem with communication within the stakeholders and a lack of consistency in the models. In this paper, by investigating the rule explaining the transformation of one of the only traditional diagrams, DFD, to SysML and reusing the formerly built models, we attempt to implement by SysML. Analyzing each diagram's Metamodel and validating the connection of each component through bipartite graph especially suggest an effective transformation rule. Also, by applying to naval-combat system, we confirm efficiency of this study. Establishing the results of this study as basis for conducting further study, we will be able to transform other previous models gained from formerly built system to SysML. In this way, the stakeholder's communication can be improved and we anticipate that the application of SysML will be beneficial to the much efficient MBSE.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.51-59
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• 2022

As the weapon system's dependence on software functions increased, software became a key factor in controlling the weapon system. In addition, as software development becomes more important domestically and internationally, software verification becomes an issue. The recent defense market has recognized this point and is demanding a plan for weapon system software maintenance. In this paper, we propose a weapon system software maintenance plan using Automatic Test Equipment. The specific method is to use a simulator to check the software function and identify failure cases. This is an effective way for developers to reduce the Total Corrective Maintenance Time(TCM) of the weapon system by reducing the time it takes to identify failure cases. It has been proven that the proposed Automatic Test Equipment can achieve software maintenance and excellent Maintainability and Operational Availability compared to the existing ones.