• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 춘계학술대회 논문집
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• pp.88-92
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• 1999

As a part of work to simulate electromagnetic environments for Hardware-In-the-Loop(HIL) simulation, the dynamic trajectory is modeled by the Way-points method and the Event-driven method for the aerial and the naval targets. The simulated results show that the Way-points method and the Event-driven method are appropriate to simulate a low speed and a high speed target respectively.

• 한국항해학회지
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• 제24권1호
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• pp.13-22
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• 2000

The collisions at sea among marine casualties are not reduced as the tonnage and speed of ship's increase as well as the traffic quantity increase at sea, in spite of the improvement of nautical equipment, enforcement of crew's education and training as well as improvement of quality standard according to the implementation of ISM code. The measures to prevent the collisions at sea are simple, and are composed of six stage.: The first stage is that the officer on duty detect the target from his eye or radar information. The second stage is determining the type and kind of target-ship. The third stage is target tracking; calculation of target speed, course, CPA and TCPA from radar information or visual check. The fourth stage is determination of vessel in danger after calculation of third stage. The fifth stage is the judgement of situation if own ship is stand-on or give way vessel according to the 1972 COLREG. The last stage is to carry out proper action according to 1972 COLREG, under the circumstances. But by the case, the situations are so different under the different external conditions; for example, natural/navigational conditions, crew's human factors, ship's particular, rule or regulation, management system on board, the condition of watch keeping. Therefore the reasons and casualties are so complicated. This study aims to investigate the collision casualty at sea which needs to clarity all these causal factors of afore-mentioned, and to analyze the causes of problems so as to utilize them to establish the measures of preventing marine accidents. This study, described the concepts of causal factors into three groups; environmental factor, and company/on board management system and navigator's act. Also described how to investigate and analyzes the casual factors. Even though it was described in this paper how to detect the causal factors and reasons of collisions, and how to analyze the inter-relation of each causal factors, it is necessary to do further study how to analyze between the liability of concerned parties and the casual factors involved.

• International Journal of Aeronautical and Space Sciences
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• 제13권4호
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• pp.468-473
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• 2012

Cost is an important aspect in designing a target drone, however the poor performance of low cost IMU, GPS, and microcontrollers prevents the use of complex algorithms, such as ARS, or INS/GPS to estimate attitude angles. We propose an autopilot which uses rate gyro and GPS only for a target drone to follow a prescribed path for anti-aircraft training. The autopilot consists of an altitude hold, roll hold, and path following controller. The altitude hold controller uses vertical speed output from a GPS to improve phugoid damping. The roll hold controller feeds back yaw rate after filtering the dutch roll oscillation to estimate the roll angle. The path following controller operates as an outer loop of the altitude and roll hold controllers. A 6-DOF simulation showed that the proposed autopilot guides the target drone to follow a prescribed path well from the view point of anti-aircraft gun training.

• 한국군사과학기술학회지
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• 제23권1호
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• pp.28-36
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• 2020

Due to the continued demand for high-definition video, video compression technology is steadily developing and the High Efficiency Video Coding standard was established in 2013. However, despite the development of this compression technology, it is very difficult to smoothly transmit VGA-level videos in Ultra-narrowband environments. In this paper, the target information preprocessing algorithm is presented for smooth transmission of target images moving in forest or open-terrain in Ultra-narrowband environment. In addition, for algorithm verification, the target information preprocessing algorithm was simulated and the simulated results were compared with the video compression result without the algorithm being applied.

• 한국군사과학기술학회지
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• 제15권1호
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• pp.66-74
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• 2012

The virtual target signal generator was developed to verify the shipborne tracking radar performance. It was used to DRFM(Digital RF Memory) method to generate the virtual moving targets. The target signal includes Doppler shift and RCS according to the target motion. And the signal generator can make jamming signal and clutter to test shipborne radar performance at real environmental condition. This paper described the functional diagram and the hardware configuration items to meet the test requirements for the tracking radar. And it showed the critical design points for the sub-systems. The signal generator which was developed in this paper shared the operational information of the radar with the radar command and control part. To test the frequency agility of the radar, it had the local oscillator which could do high speed frequency switching according to radar information. By communicating between the signal generator and the radar command and control part, the local oscillator of signal generator could be controlled every pulse. It reduced the instantaneous bandwidth of signal generator and minimized the spurious. So it lowered the probability of generating wrong targets.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권3호
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• pp.238-244
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• 2012

A modeling of vision based robot formation control system using fuzzy logic controller and extended Kalman filter is presented in this paper. The main problems affecting formation controls using fuzzy logic controller and vision based robots are: a robot's position in a formation need to be maintained, how to develop the membership function in order to obtain the optimal fuzzy system control that has the ability to do the formation control and the noise coming from camera process changes the position of references view. In order to handle these problems, we propose a fuzzy logic controller system equipped with a dynamic output membership function that controls the speed of the robot wheels to handle the maintenance position in formation. The output membership function changes over time based on changes in input at time t-1 to t. The noises appearing in image processing change the virtual target point positions are handled by Extended Kalman filter. The virtual target positions are established in order to define the formations. The virtual target point positions can be changed at any time in accordance with the desired formation. These algorithms have been validated through simulation. The simulations confirm that the follower robots reach their target point in a short time and are able to maintain their position in the formation although the noises change the target point positions.

• 한국시뮬레이션학회논문지
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• 제26권3호
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• pp.65-72
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• 2017

함정 전투실험의 사후분석에서는 객체에 대한 자함의 표적 탐지능력와 무장 교전능력을 분석한다. 따라서 사후분석을 위해서는 전장 환경의 위협 객체와 센서에서 탐지한 표적간 연관 맺을 수 있는 정보가 필요하다. 기존의 공학급 교전 시뮬레이터는 이러한 객체-표적 연관정보를 제공하였다. 그러나 사용된 시뮬레이터의 잠수함모델에는 실제 소나시스템의 신호처리 알고리즘이 탑재되어있다. 소나신호처리 과정을 통해 얻은 표적정보에서는 실제 객체정보가 무엇인지 연관지을 수 없으며, 사용된 시뮬레이터도 그러한 정보를 제공하지 않고 있다. 따라서 본 연구에서는 객체정보와 소나신호처리에서 얻은 표적의 방위각, 거리, 속도 등의 기동정보를 이용하여 객체-표적 연관정보를 생성하였다. 객체-표적 연관정보를 생성하는 방법을 제안하고, 제안한 방법의 타당성을 실험을 통해 검증하였다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.252-257
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• 2005

In this work, we propose a simple but efficient method to design a target temperature trajectory for pulling speed tracking control of the crystal grower in the Czochralski crystallization process. In the suggested method, the model predictive control strategy is used to incorporate the complex dynamic effect of the heater temperature on the pulling speed into the temperature trajectory design quantitatively. The feedforward trajectories designed by the proposed method were implemented on 200 mm and 300 mm silicon crystal growers in the commercial Czochralski process. The application results have demonstrated its excellent and consistent tracking performance of pulling speed along whole bulk crystal growth.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.177-182
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• 2002

In the paper, the development of high-speed industrial turbo blowers with foil air bearings is presented as a first successful commercialization in the world. Their target market is various from wastewater treatment to cement factory processes which require compressed air ranging between 0.6 and 0.8 bar gauge. Employing the state-of·the-art technology of the high-speed BLDC motors, the bump-type foil air bearings and the high- efficient turbo impellers/diffusers, so much compact, efficient and silent blower machines of a single stage are now available in the market, aiming to replace the existing inefficient, bulky and noisy ones, such as roots blowers. The first production lines are established fur 25,75 and 150 hp class blowers. Rotational speeds from about 20,000 to 80,000 rpm are realized directly from the high-speed BLDC motors without any gear boxes, and no lubrication oil is required. A brief introduction of design, manufacture and test results is presented fur mechanical, electrical and aerodynamic performance.

• 한국위성정보통신학회논문지
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• 제11권1호
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• pp.46-50
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• 2016

The adaptive power control of Code Division Multiple Access (CDMA) systems for communications between User Equipments (UEs) with a link-budget based Signal-to-Interference Ratio (SIR) estimate which has distance information is applied to three inner loop power control algorithms. The speed estimation performances of these algorithms with their consecutive Transmit-Power-Control (TPC) ratios are compared to each other, and it is concluded that the speed can be estimated using the TPC ratio information of Consecutive TPC Ratio Step-size Closed Loop Power Control (CS-CLPC) and Fixed Step-size Power Control (FSPC).