• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.102-108
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• 2016

A flying drone generates vibrations in a great variety of frequencies, and it requires a gimbal system stabilization loop design in order to obtain clean and accurate image from the camera attached to the drone under this environment. The gimbal system for drone comprises the structure that supports the camera module and the stabilization loop which follows the precise angle while blocking the vibration from outside. This study developed a dynamic model for one axis for the stabilization loop design of a gimbal system for drones and applied classical PID controller and intelligent PID controller. The Stabilization loop design was developed by using MATLAB/Simulink and compared the performance of each controller through simulation. Especially, the intelligent PID controller can be designed almost without the dynamic model and it demonstrates that the angle can be followed without readjusting the parameters of the controller even when the characteristics of the model changes.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.209-215
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• 2022

As intelligent autonomous driving vehicle development has become a big topic around the world, accurate reference dynamics estimation has been more important than before. Current systems generally use speed and heading information sensed from a distant point as a vehicle reference dynamic, however, the dynamics between different points are not same especially during rotating motions. In order to estimate properly estimate the reference dynamics from the information such as velocity and heading sensed at a point distant from the reference point such as center of gravity, this study proposes estimating reference dynamics from any location in the vehicle by combining the Bicycle and Ackermann models. A test system was constructed by implementing multiple GNSS/INS equipment on an Robot Operating System (ROS) and an actual car. Angle and speed errors of 10° and 0.2 m/s have been reduced to 0.2° and 0.06 m/s after applying the suggested method.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.213-216
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• 2022

There has been an increase in video surveillance for public safety and security, which increases the video data, leading to analysis, and storage issues. Furthermore, most surveillance videos contain an empty frame of hours of video footage; thus, extracting useful information is crucial. The prominent framework used in surveillance for efficient storage and analysis is video synopsis. However, the existing video synopsis procedure is not applicable for creating an abnormal object-based synopsis. Therefore, we proposed a lightweight synopsis methodology that initially detects and extracts abnormal foreground objects and their respective backgrounds, which is stitched to construct a synopsis.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.142-144
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• 2023

실생활에서 CCTV가 증가함에 따라 영상에서 개인정보 유출에 대한 관심도 증가하고 있다. CCTV로 녹화된 영상에서는 다양한 개인정보가 노출될 수 있기 때문에, 개인정보를 비식별화할 수 있는 영상 암호화 기술이 필요하다. 현재 다양한 영상녹화 장치에서 효율성을 위해 HEVC가 많이 사용되고 있으며, HEVC 영상에서 관심영역만을 암호화하는 실시간 관심영역 암호화 기술이 연구되고 있다. 기존의 HEVC 영상에서 관심영역 암호화 기법은 모든 프레임의 관심영역에 포함되는 타일을 암호화하므로 많은 연산자원을 필요로 한다. 본 논문에서는 선별된 일부 프레임에서 관심영역에 포함되는 타일을 선택적으로 암호화하여, 모든 프레임에서 관심영역의 비식별화를 유지하며 암호화 성능을 향상하는 방법을 제안한다. 결과적으로 제안한 방법을 사용함으로써 영상 암호화 시 전체 프레임에 대한 비식별화를 유지하면서 기존 방법보다 암호화에 걸리는 시간이 50.4% 감소하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.92-94
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• 2023

사물인터넷이 발전함에 따라 사용자에게 여러 서비스를 제공하기 위한 사물인터넷 플랫폼이 활발하게 개발되고 있다. 그러나 각각의 플랫폼은 독자적인 환경에서 개발되고 있어 상호운용성에 어려움이 있다. 특히, 이기종 사물인터넷 플랫폼이 리소스 보호를 위해 동일한 속성기반 접근제어를 사용하더라도 속성을 표현하는 표현법이 상이하여 유효한 속성을 소유하고 있음에도 타 플랫폼의 리소스에 접근할 수 없는 문제가 있다. 이에, 본 논문에서는 속성기반 접근제어를 활용하는 이기종 사물인터넷플랫폼 간의 서로 다른 속성 표현법을 이해하여 상호운용할 수 있는 프레임워크를 제안한다. 본 프레임워크는 자가적응 모듈을 통해 동일한 속성이더라도 표현법의 차이로 발생하는 상호운용의 문제를 해결하여 이기종 플랫폼 간의 리소스 접근이 가능하도록 한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.536-541
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• 2015

In this paper, we propose a the image-based automatic flight control system for the mini drone. Automatic flight system with a camera on the ceiling and markers on the floor and landing position is designed in an indoor environment. Images from the ceiling camera is used not only to recognize the makers and landing position but also to track the drone motion. PC sever identifies the location of the drone and sends control commands to the mini drone. Flight controller of the mini drone is designed using state-machine algorithm, PID control and way-point position control method. From the, The proposed automatic flight control system is verified through the experiments of the mini drone. We see that known makers in environment are recognized and the drone can follows the trajectories with the specific ㄱ, ㄷ and ㅁ shapes. Also, experimental results show that the drone can approach and correctly land on the target positions which are set at different height.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.635-642
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• 2023

With the development of artificial intelligence technology, drones are evolving beyond simple remote control tools into intelligent drones that perform missions autonomously. The importance of drones is gradually gaining attention due to the use of drones in overseas military conflicts and the analysis of the future operational environment in Korea. AMAD is proposed for the rapid development of intelligent drones. In order to develop intelligent software based on AMAD, an integrated development environment (IDE) that supports users with functions such as debugging, performance evaluation, and monitoring is essential. In this paper, we define the concepts of the development environment required for intelligent software development and describe the results of reflecting them in the design of the IDE and AMAD's agents, SVI and MPD, which are interfaced with the IDE.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.4
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• pp.122-131
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• 2017

This study was a drone-utilized case study motivated by that drones can obtain sophisticated video image data previously not feasible. The dilemma zones on selected intersection approaches were identified and locations of drivers' decision making to stop or go at the onset of yellow were determined by analyzing drone video images. The gap between the drivers' decision making location and invisible stop/go border line provided by the yellow time interval was defined as "risky passing zone". To improve the dilemma zone safety problems, re-optimization of yellow time intervals and introduction of new pavement marking that can help drivers decision making on yellow indication are suggested.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.132-137
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• 2017

Drone is currently used for wide application areas in our real life. Also it performs more important functions. We propose a method of drone operation system for the prevention of industrial disaster. In normal operation of drone system the drone monitors the industrial sites according to the planned flight path with acquiring the monitored images and send the image information to the server. The server analyzes and compares the images to DB information by calculating the similarity based on the threshold. Then the system decides whether the industrial sites has problems or not. If the abnormal condition is occurred, the drone change the flight path to abnormal flight path and keep monitoring the industrial sites with measuring the air status by sensors and sends all information to server system on the ground. If the emergency case is occurred, drone approaches the closest position of accident points and acquiring the all information and send them to server and 119 center.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.63-71
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• 2022

Barometers have been used to calculate altitude, and with the development of technology, barometer which had a large volume have now been reduced to about centimeter-level. The altitude calculation using barometer is proceeded using the relationship between reference sea level pressure and the pressure obtained by barometer, and for this, pre-calibration of the barometer is essential. In addition, the barometer has a certain level of bias from actual pressure due to production, and many smartphone manufacturers correct it during the manufacturing process, but it is difficult to correct errors caused by environmental variables. In this paper, we extended methodology of correcting barometer using static reference station to moving drone, and it was possible to calculate the altitude more accurately.