• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.132-135
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• 2000

In this paper, we propose to exploit a multi-code CDMA scheme for power line communication (PLC) systems, and its performance on non-Gaussian impulse and harmonic noises is presented. The proposed multi-code CDMA scheme utilizes convolutional coding and block interleaving to combat with the non-Gaussian noises, and simulation results indicate effective alleviation of these noises, and thus significant bit error rate improvement by the proposed scheme even under strict restriction of frequency band allowed in PLC systems.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.55-66
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• 2023

In recent years, naval vessels have been developed to fulfill a variety of missions by being equipped with various cutting-edge equipment and ICT technologies. One of the main missions of Korean naval vessels is anti-ballistic missile warfare to defend key units and areas against the growing threat of ballistic missiles. Because the process of detection and interception is too complex and the cost of failure is much high, a lot of preparation is required to effectively conduct anti-ballistic missile warfare. This paper describes the development of a simulation model of anti-ballistic missile warfare with combat systems and equipment to be installed on future naval vessels. In particular, the DEVS formalism providing a modular and hierarchical modeling manner was applied to the simulation model, which can be utilized to efficiently represent various anti-ballistic missile warfare situations. In the simulation results presented, experiments were conducted to analyze the effectiveness of the model for effective detection resource management in anti-ballistic missile warfare. This study is expected to be utilized as a variety of analysis tools necessary to determine the optimal deployment and configuration of combat resources and operational tactics required for effective anti-ballistic missile warfare of ships in the future.

• International Journal of Fluid Machinery and Systems
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• v.5 no.2
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• pp.91-99
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• 2012

The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting Engine gearbox (EGB) with Accessory Gear Box (AGB). The HSFC transmits the power through series of specially contoured metallic annular thin flexible plates whose planes are normal to the torque axis. The HSFC operates at high speed ranging from 10,000 to 18,000 rpm. The HSFC is also catered for accommodating larger lateral and axial misalignment resulting from differential thermal expansion of the aircraft engine and mounting arrangement. The contoured titanium alloy flexible plates are designed with a thin cross sectional profile to accommodate axial and parallel misalignment by the elastic material flexure. This paper investigates the effect of misalignment on the transmission characteristics of the HSFC couplings. A mathematical model for the HSFC coupling with misalignment has been developed for analyzing the torque transmission and force interaction characteristics. An extensive testing has been conducted for validating characteristics of the designed coupling under various misalignment conditions. With this the suitability of the model adapted for the design iteration of HSFC development is validated. This method will reduce the design iteration cycles of HSFC and can be extended for the similar development of flexible couplings.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.572-578
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• 2011

In this paper, the result of study on the effectiveness of anti-submarine defense plan according to the disposition of surface ships has been proposed. The surface ship carries a hull mounted sonar(HMS) as a underwater sensor and a torpedo acoustic counter measure(TACM) as a soft-kill weapon against torpedo attacks from the enemy. Nowadays these underwater systems have been combined into a integrated anti-submarine warfare combat system. And in the real anti-submarine operation environment, several surface ships cooperate for executing ASW plans. Considering these ASW systems and the ASW environment, the models of underwater systems mounted on an surface ship and the a general model of anti-submarine defense plan are proposed. And we designed a scenario for conducting simulations to evaluate the ASW plan according to the variation of the range and the relative angle between surface ships and a capital ship. The simulation results show the effectiveness of ASW plan depends on the formation of surface ships and a capital ship.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.69-77
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• 2011

Modeling and Simulation(M&S) technology gets an attention from various parts such as industry and military. Especially, military uses the technology to cope with a different situation from the one in the Cold War and maximize the effect of training against the cost in the new environment. In order for the training based on M&S technology to be effective, the situations of a battlefield and a combat must be more realistically simulated. For this, a technique development on Computer-Generated Forces(CGF) which represents a unit's simulation logic and a human's simulated behaviors is focused. The CGF simulating a human's behaviors can be used in representing an enemy force, experimenting behaviors in a future war, and developing a new combat idea. This paper describes a methodology to accomplish Computer-Generated Forces' autonomous intelligence. It explains the process of applying a task behavior list based on the METT+T element onto CGFs. On the other hand, in the domain knowledge of military field manual, fuzzy facts such as "fast" and "sufficient" whose real values should be decided by domain experts can be easily found. In order to efficiently implement military simulation logics involved with such subjectivity, using a fuzzy inference methodology can be effective. In this study, a fuzzy inference methodology is also applied.

• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.41-58
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• 2023

As naval warfare changes to composite warfare that includes simultaneous engagements against surface, underwater, and air enemies, performance and tactical analysis are required to respond to naval warfare. In particular, for practical analysis of composite warfare, it is necessary to study engagement simulations that can appropriately utilize the limited performance resources of the detection system. This paper proposes a DEVS (Discrete Event Systems Specifications)-based simulation model for composite warfare analysis. The proposed model contains generalized models of combat platforms and armed objects to simulate various complex warfare situations. In addition, we propose a detection performance allocation algorithm that can be applied to a detection system model, considering the characteristics of composite warfare in which missions must be performed using limited detection resources. We experimented with the effectiveness of composite warfare according to the strength of the detection system's resource allocation, the enemy force's size, and the friendly force's departure location. The simulation results showed the effect of the resource allocation function on engagement time and success. Our model will be used as an engineering basis for analyzing the tactics of warships in various complex warfare situations in the future.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.175-183
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• 2014

In spite of international efforts to control nuclear weapons and chemical, biological, and radiological (CBR) weapons, North Korea obtains and sells CBR weapons illegally. As a result, the worldwide threat of CBR weapons is increasing. Unfortunately, civil defense education and training for CBR weapons have not been adopted for real situations because of the long period of absence of an actual combat. In this study, virtual training scenarios that are applied to the simulation were made in 5 steps to cope with CBR situations. These scenarios are expected to have three effects. First, trainings can be improved with experience and education. Second, the problems and health hazards of CBR weapons and supplies can be solved with CBR virtual training simulation experience. Finally, corresponding effects can be recognized and predicted in real situations through roles and mission procedures of simulation scenario.

• Journal of the military operations research society of Korea
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• v.34 no.1
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• pp.1-11
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• 2008

A methodology for the improvement of simulation based training system for the artillery is proposed in this paper. The complex nonlinear relationship inherent among parameters in artillery firing is difficult to model and analyze. By introducing neural network based simulation, accurate representation of artillery firing is made possible. The artillery training system can greatly benefit from the improved prediction. Neural networks learning is conducted using the conjugate gradient algorithm. The evaluation of the proposed methodology is performed through simulation. Prediction errors of both regression analysis model and neural networks model are analyzed. Implementation of neural networks to training system enables more realistic training, improved combat power and reduced budget.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.540-547
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• 2015

This paper describes development contents and flight tests of an ACMI simulator based on LVC integrating architecture. ACMI is the system that provides air combat training and ground bombing training for improving fighting efficiency, that is the live simulation involving real people to operate real systems. ACMI simulator was developed for technic acquisition of LVC interoperability by using data link communication. ACMI simulator simulated maneuvering of a fighter by operating an UAV, a fighter can be distinguished from an UAV by maneuvering characteristics. This study proposes maneuvering simulation method by using flight data of the UAV, and performed its flight test for verifying similarity of fighter maneuvering.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.706-718
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• 2002

In bluetooth system, there are two kinds of interference. One is the frequency static interference, for example 802.11 direct sequence, the interferer uses fixed frequency band. Another is frequency dynamic interference, for example other piconets or 802.11 frequency hopping, the interferer uses dynamic frequency channel and cant be estimated. In this paper we introduce a novel solution of hybrid method of Listen-Before-Talk (LBT) and Adaptive Frequency Hopping (AFH) to address the coexistence of bluetooth and Direct Sequence of wireless local area network (WLAN). Before any bluetooth packet transmission, in the turn around time of the current slot, both the sender and receiver sense the channel whether there is any transmission going on or not. If the channel is busy, packet transmission is withdrawn until another chance. This is the LBT in Bluetooth. Because of asymmetry sense ability of WLAN and bluetooth, AFH is introduced to combat the left front-edge packet collisions. In monitor period of AFH, LBT is performed to label the channels with static interference. Then, all the labeled noisy channels are not used in the followed bluetooth frequency hopping. In this way, both the frequency dynamic and frequency static interference are effectively mitigated. We evaluate the solution through packet collision analysis and a detail realistic simulation with IP traffic. It turns out that the hybrid method can combat both the frequency dynamic and frequency static interference. The packet collision analysis shows it almost doubles the maximal system aggregate throughput. The realistic simulation shows it has the least packet loss.