• Journal of the military operations research society of Korea
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• v.16 no.1
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• pp.18-34
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• 1990

In light of the recent developments of transitory nature, it is likely that national defense decision-making will be more difficult to make for years to come. In other words, sudden changes in security environment would call into question the basic assumptions on which we have built our national defense planning and increase the number of the uncertain factors in the decision-making process; the subdivision and ramification of national defense management would increase the factors for decision-making and complicate even further the mutual interactions among these factors; the accelerated pace of sophistication and diversification of weapon systems and military technology would increase the risk of failure and system costs geometrically; and the reduced level of acceptance among the people on the sanctification of national defense in proportion to the rapid progress toward a more democratic and industrial society would engender an increased criticism or checking role by the National Assembly or by the mass media. As the changes in national defense environment and conditions create an innumerable number of new tasks, this paper intends to suggest a few core policy measures to improve the quality of national defense decision-making. More specifically, it proposes to 1) eradicate entirely the bureaucratic behavior and tendencies; 2) utilize actively the brain staff for quality assurance of decision-making; 3) and introduce and apply as a whole set, a total system, or an incorporated pack age the PPBEES(Planning-Programming-Budgeting-Executing-Evaluating-System)/LCMM (Life-Cycle Management Model for System Acquision), the OR/SA(Operations Research/Systems Analysis), and DMIS (Defense Management Information System).

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.5
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• pp.619-627
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• 2024

As AI technology advances, interest in performing multi-robot autonomous missions for manned-unmanned teaming (MUM-T) is increasing. In order to develop autonomous mission performance technology for multiple robots, simulation technology that reflects the characteristics of real robots and can flexibly apply various missions is needed. Additionally, in order to solve complex non-linear tasks, an API must be provided to apply multi-robot reinforcement learning technology, which is currently under active research. In this study, we propose the campaign model to flexibly simulate the missions of multiple robots. We then discuss the results of developing a simulation environment that can be edited and run and provides a reinforcement learning API including acceleration performance. The proposed simulated control module and simulated environment were verified using an enemy infiltration scenario, and parallel processing performance for efficient reinforcement learning was confirmed through experiments.

• Journal of Korean Society for Quality Management
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• v.44 no.3
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• pp.473-486
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• 2016

Purpose: Although the price reduction policy is established for military supplies, it is more focused on general military items. Therefore, it is hard to apply the current price reduction policy directly to the major weapon system. The purpose of this study is to develop an evaluation model which generates appropriate outputs for price reduction of military supplies. Methods: To improve the current policy, we first analyze the relevant policies of price reduction of similar organizations. We gather the opinions of related organization through survey including DAPA, Logistics Command, DTaQ and Defense industry companies. Then, we develop a price reduction model based on the analytic hierarchical process(AHP) method to find out important factors for price reduction. Results: The results of AHP analysis show that the important factors when applying price reduction of military supplies. From the analysis, the proposed method effectively generates the amounts of price reduction for the nonconformance items. Conclusion: The results of this research will be used as guidelines to improve military supplies policy of price reduction.

• Current Optics and Photonics
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• v.7 no.1
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• pp.1-14
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• 2023

Wavefront-coding imaging can achieve high-quality imaging along with a wide range of defocus. In this paper, the anti-laser detection and damage performance of wavefront-coding imaging systems using different asymmetric phase masks are studied, through modeling and simulation. Based on FresnelKirchhoff diffraction theory, the laser-propagation model of the wavefront-coding imaging system is established. The model uses defocus distance rather than wave aberration to characterize the degree of defocus of an imaging system. Then, based on a given defocus range, an optimization method based on Fisher information is used to determine the optimal phase-mask parameters. Finally, the anti-laser detection and damage performance of asymmetric phase masks at different defocus distances and propagation distances are simulated and analyzed. When studying the influence of defocus distance, compared to conventional imaging, the maximum single-pixel receiving power and echo-detection receiving power of asymmetric phase masks are reduced by about one and two orders of magnitude respectively. When exploring the influence of propagation distance, the maximum single-pixel receiving power of asymmetric phase masks decreases by about one order of magnitude and remains stable, and the echodetection receiving power gradually decreases with increasing propagation distance, until it approaches zero.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.98-104
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• 2016

With the development of modern science and technology, weapon systems such as tanks, submarines, combat planes, radar are also dramatically advanced. Among these weapon systems, the ballistic missile, one of the asymmetric forces, could be considered as a very economical means to attack the core facilities of the other country in order to achieve the strategic goals of the country during the war. Because of the current ballistic missile threat from the North Korea, establishing a missile defense (MD) system becomes one of the major national defense issues. This study focused on the optimization of air defense artillery units' deployment for effective ballistic missile defense. To optimize the deployment of the units, firstly this study examined the possibility of defense, according to the presence of orbital coordinates of ballistic missiles in the limited defense range of air defense artillery units. This constraint on the defense range is originated from the characteristics of anti-ballistic missiles (ABMs) such as PATRIOT. Secondly, this study proposed the optimized mathematical model considering the total covering problem of binary integer programming, as an optimal deployment of air defense artillery units for defending every core defense facility with the least number of such units. Finally, numerical experiments were conducted to show how the suggested approach works. Assuming the current state of the Korean peninsula, the study arbitrarily set ballistic missile bases of the North Korea and core defense facilities of the South Korea. Under these conditions, numerical experiments were executed by utilizing MATLAB R2010a of the MathWorks, Inc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3005-3027
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• 2015

Spam has become one of the top threats of micro-blogging networks as the representations of rumor spreading, advertisement abusing and malware distribution. With the increasing popularity of micro-blogging, the problems will exacerbate. Prior detection tools are either designed for specific types of spams or not robust enough. Spammers may escape easily from being detected by adjusting their behaviors. In this paper, we present a novel model to quantitatively evaluate information diffusion in micro-blogging networks. Under this model, we found that spam posts differ wildly from the non-spam ones. First, the propagations of non-spam posts mostly result from their followers, but those of spam posts are mainly from strangers. Second, the non-spam posts relatively last longer than the spam posts. Besides, the non-spam posts always get their first reposts/comments much sooner than the spam posts. With the features defined in our model, we propose an RBF-based approach to detect spams. Different from the previous works, in which the features are extracted from individual profiles or contents, the diffusion features are not determined by any single user but the crowd. Thus, our method is more robust because any single user's behavior changes will not affect the effectiveness. Besides, although the spams vary in types and forms, they're propagated in the same way, so our method is effective for all types of spams. With the real data crawled from the leading micro-blogging services of China, we are able to evaluate the effectiveness of our model. The experiment results show that our model can achieve high accuracy both in precision and recall.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.81-88
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• 2013

The component based propulsion modeling and simulation of an dual ramjet engine using Taylor-Maccoll flow equation and quasi 1-D combustor model. The subsonic and supersonic intake were modeled with Taylor-Maccoll flow having $25^{\circ}$ cone angle, the gas generator which transfers a pre-combustion gas into supersonic combustor was developed using Lumped model, and the determination of the size of nozzle throat of a gas generator was described. A quasi 1-D model was applied to model a supersonic combustor and the variation of temperature and pressure inside combustor were presented. Furthermore, the thrust and specific impulse applying fuel regulation by pressure recovery ratio and equivalence ratio were derived.

• Journal of the military operations research society of Korea
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• v.6 no.2
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• pp.151-184
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• 1980

Simple models for a defense consisting of a preinstalled mine field possibly defended by an anti-tank weapon are derived and analyzed. This paper uses a special Poisson process to model the one or two positions of mines in the mine field. The duel between the anti-tank weapon and offensive tanks crossing the field is modeled with a continuous time Markov chain. Some algebraic solutions and numerical results are obtained for specific scenarios.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.89-99
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• 1999

The major objective of this research is to propose a design architecture for autonomous defense systems for supporting highly intelligent behavior by combining decision, perception, and action components. Systems with such high levels of autonomy are critical for advanced battlefield missions. By integrating a plenty of advanced modeling concepts such as system entity structure, endomorphic modeling, engine-based modeling, and hierarchical encapsulation & abstraction principle, we have proposed four layered design methodology for autonomous defense systems that can support an intelligent behavior under the complicated and unstable warfare. Proposed methodology has been successfully applied to a design of autonomous tank systems capable of supporting the autonomous planning, sensing, control, and diagnosis.

• Journal of Korea Multimedia Society
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• v.22 no.8
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• pp.930-939
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• 2019

High-Level Architecture(HLA)/Run-Time Infrastructure(RTI) are standards for distributed simulation systems and offer a technology to interconnect them and form one single simulation system. In defense domain, M&S is the only way to prove effectiveness of weapon systems except for Live Fire Testing (LFT). This paper focuses on guided missile simulations in weapon systems for engagement analyses and proposes the integrated flying vehicle model that is based on HLA/RTI. There are a lot of missiles in real world; therefore, we should develop each missile models in M&S in order to apply battlefield scenarios. To deal with the difficulties, in this paper, firstly, I classify these missiles into three models: ballastic, cruise, and surface-to-air missile models, and then I design each missile model and integrates them into a single model. This paper also offers a case study with my integrated flying vehicle model. At the conclusion, this paper presents contributions of this paper.