• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.21-33
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• 2020

This study develops a simulator for determining the sonar sensor configuration of unmanned underwater vehicles (UUVs) based on a scenario, in order for UUVs to conduct an effective anti-submarine warfare (ASW). First, we analyze the missions and operational concepts of UUVs in the field of ASW, and then select a Hold-at-Risk scenario as the one with the highest priority. Next, for modeling the components of a simulator, the motion, acoustic characteristic, and environment condition of the platforms (UUV and target submarine) are specified. Especially, based on the beam pattern of each sonar configuration considered in this paper, the passive sonar equation is used to verify target detection, and we further estimate the azimuth and elevation of the target using amplitude and phase of the received signal, respectively. The simulation results show the performance tendency depending on the sonar sensor configurations of a UUV, and the simulator provides a high applicability under various scenarios.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.65-72
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• 2017

We propose a method to generate the object-target identifier mapping information for system performance and effectiveness analysis of submarine engage system and verify the validity of the proposed method through experiments. In the submarine model of the engage simulator, the signal processing algorithm of the actual sonar system is installed. In the target information obtained through the sonar or signal processing process, the actual object information is not known, and the simulator does not provide such information. Therefore, in this study, we generated identifier mapping information for simulation post-analysis by using bearing, range, and speed of the target obtaind from sonar signal processing and the object collected.

• The Journal of the Acoustical Society of Korea
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• v.33 no.3
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• pp.163-173
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• 2014

Sound propagation algorithm for a sonar simulator is required to run in real-time and should be able to model the range and depth dependence of the Korean ocean environments. Ray model satisfies these requirements and we developed an algorithm for range-dependent ocean environments. In this algorithm, we considered depth-dependence of sound speed through rays based on a rectangular cell method and layer method. Range-dependence of sound speed was implemented based on a split-step method in the range direction. Eigen-ray is calculated through an interpolation of ray bundles and Gaussian interpolation function was used. The received time signal of sonar was simulated by Fourier transform of eigen-ray solution in the frequency domain. Finally, for the verification of proposed algorithm, we compared the results of transmission loss with other validated models such as BELLHOP, SNUPE, KRAKEN and OASES, for the Pekeris waveguide, wedge, and deep ocean environments. As a result, we obtained satisfactory agreements among them.

• Journal of the Korea Society for Simulation
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• v.30 no.2
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• pp.11-22
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• 2021

Sonobuoy is widely used as a very important sensor in combat management system using P-3 patrol aircraft due to its advantages of rapid searching into wide exploration range. It is necessary to verify the performance of developed sonobuoy system using various maritime test data in order to be successfully applied in combat management system. But it is difficult to acquire various real maritime data because it needs much time and effort. Therefore we have developed in this paper a synthetic signal generator and a simulator that they can verify the performance of sonobuoy system and evaluate its operational effectiveness without conducting maritime test. We have synthesized target signals based on the characteristics of underwater sound sources, and then developed the synthesized signal generator which consider to sound propagation etc. like as underwater environment. And in the simulator development we use a HMI technique to enhance the convenience of operator, and design to verify the performance of sonobuoy system. The developed signal generator and simulator can be used as useful tools to evaluate the operational effectiveness such as optimal deployment of sonobuoy in combat management system using P-3 patrol aircraft.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.99-106
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• 2010

In the anti-submarine warfare, a search using HMS is used as a basic strategy. The importance of HMS operation strategy is increasing, but it is hard to develop effective anti-submarine search strategy due to reciprocal actions among sea environments, search patterns, sonar operational tactics, anti-submarine search strategy, etc. In this research, a simulator was invented so as to analyze anti-submarine search patterns used when an HMS-carrying ship searches for submarine in various anti-submarine search environments. The simulator reflects various factors that influence anti-submarine search, and with consideration of search patterns of anti-submarine ships as well as evasive movement of submarines, it can simulate various anti-submarine search operations such as a collaborative anti-submarine operation by a single or multiple forces. Also, the simulator will contribute to developing and improving systematic and efficient HMS operational tactics in anti-submarine warfare.

• Journal of the Korea Computer Graphics Society
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• v.26 no.1
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• pp.1-6
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• 2020

Patella surgery of small animal is an important veterinary surgery that the veterinarian should saw and drill the dislocated patella in order to fix the corrected position. However, the animal protection laws restrict the veterinarian students' chances for the practice and training of the patella surgery. This paper proposed a haptic based patella surgery simulator for veterinarian students. We modelled force feedback methods in order to provide best similar haptic feedbacks to the real drilling feedbacks in the patella surgery. The proposed patella drilling simulator provides haptic interface as a drill and a workbench in order to provide best surgery experiences. We conducted the performance evaluations in order to prove usability of the proposed patella surgery interface.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.171-172
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• 2006

국내 전력계통을 담당하고 있는 한국전력공사에서는 주기적으로 변전소 운전원들을 교육/훈련하여 계통상에서 발생하는 각종 현상 또는 고장 등에 대한 신속한 대비를 수행할 수 있도록 하고 있다. 이러한 교육/훈련을 위하여 교육용 시뮬레이터를 개발하여 운영 중에 있다. 기존 교육용 시뮬레이터의 경우 여러 고장 발생에 대한 각종 동작 사항을 지정하여 시나리오로 저장한 후, 교육/훈련시 다시 불러와서 사용하는 방식으로 되어 있었으나 본 개발된 고장발생기는 고장 유형에 따른 동작 사항을 계통 상황에 맞춰 생성하여 시나리오를 발생시키는 방식으로 변경하였다. 이를 통해 복잡한 시나리오 편집 절자가 없어졌으며, 보다 다양한 고장에 대한 교육/훈련을 수행할 수 있게 되었다. 본 논문에서는 고장발생기의 입력 및 출력을 제시하고, 기존의 고장발생 방식과의 성능 비교를 기술하였다.

• The Journal of the Acoustical Society of Korea
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• v.33 no.4
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• pp.232-237
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• 2014

A passive sonar of warship is composed of several directional or omni-directional sensors. In order to model the acoustic signal received into a warship sonar, the wave propagation modeling is usually required from arbitrary noise source to all sensors equipped to the sonar. However, the full calculation for all sensors is time-consuming and the performance of sonar simulator deteriorates. In this study, we suggest an asymptotic method to estimate the sonar signal arrived to sensors adjacent to the reference sensor, where it is assumed that all information of eigenrays is known. This method is developed using Taylor series for the time delay of eigenray and similar to Fraunhofer and Fresnel approximation for sonar aperture. To validate the proposed method, some numerical experiments are performed for the passive sonar. The approximation when the second-order term is kept is vastly superior. In addition, the error criterion for each approximation is provided with a practical example.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.472-483
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• 2013

Actual maritime exercise for improving the capability of submarine sonar operator leads to a lot of cost and constraints. Sonar simulator maximizes the capability of sonar operator and training effect by solving these problems and simulating a realistic battlefield environment. In this study, a passive sonar simulator algorithm is suggested, where the simulator is divided into three modules: maneuvering module, noise source module, and sound propagation module. Maneuvering module is implemented in three-dimensional coordinate system and time interval is set as the rate of vessel changing course. Noise source module consists of target noise, ocean ambient noise, and self noise. Target noise is divided into modulated/unmodulated and narrowband/broadband signals as their frequency characteristics, and they are applied to ship radiated noise level depending on the vessel tonnage and velocity. Ocean ambient noise is simulated depending on the wind noise considering the waveguide effect and other ambient noise. Self noise is also simulated for flow noise and insertion loss of sonar-dome. The sound propagation module is based on ray propagation, where summation of amplitude, phase, and time delay for each eigen-ray is multiplied by target noise in the frequency domain. Finally, simulated results based on various scenarios are in good agreement with generated noise in the real ocean.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.1-7
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• 2008

The objective of the KA-32 Helicopter Training Simulator Development Program, executed by the Republic of Korea Government, is to acquire a helicopter simulator which meets level C requirements in accordance with the FAA AC 120-63. The Korea Aerospace Research Institute (KARI) manages the development program and is supposed to develop and validate the flight dynamics model based on simulator design data and flight test data. The helicopter chosen for this project is the Kamov KA32T, operated by the Korean Forest Aviation Office. This paper presents the test program and information about the installation and execution of the flight tests. The program consist of tests for the simulator qualification, additional tests for model data and additional tests for model validation. The flight trials were performed from 30 July to 31 August at the Iksan airbase of the Forest Aviation Office (FAO).