• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.249-250
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• 2008

본 연구는 전년도 지형참조항법(TRN; Terrain Referenced Navigation)에 근거하는 3-D 헬리콥터 항법 시스템을 위한 알고리즘 개발의 후속 연구로서 실용적 완성을 위해 수행되었다. 본 연구에서 헬리콥터의 위성항법장치(GPS)로부터의 정보(X,Y,Z 좌표)는 자동차가 도로주행중 매 1초 간격으로 수신되는 GPGGA Code로 대체되었다. 비행체는 3차원 직교 좌표 체계(Cartesian coordinate system)로 표현되는 수치지형모델(DTM; Digital Terrain Model)상에서 시점(Origination)-종점(Destination) 분석 기법에 의해 항로를 결정한다. 본 시스템은 우선 조종사에게 지형의 사전 인식을 위해 시점-종점 주변 3차원 지형도와 항로의 종단면도를 보여준다. 본 시스템은 직접적인 지상 충돌을 피하기 위해 지형 여유 층면(Terrain Clearance Floor)의 개념을 도입, 기복 지형 표면에 일정 높이의 완충 공간을 설정한다. 본 시스템은 매초 GPS로부터 실시간 수신되는 X,Y,Z 위치와 DTM상의 x,y,z를 비교하여 만약 비행체가 완충 공간에 접근하게 되면 즉시 경고음과 메시지를 발한다. 수치지형모델은 (주)첨성대가 확보하고 있는 3초 간격의 DTM을 채택, 작성하였다.

• International Journal of Control, Automation, and Systems
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• v.5 no.1
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• pp.15-23
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• 2007

In surveillance, monitoring, and target tracking operations, high-resolution images should be obtained even if the target is in a far distance. Frequent movements of vehicles such as boats degrade the image quality of onboard camera systems. Therefore, stabilizer mechanisms are required to stabilize the line of sight of boatboard camera systems against boat movements. This paper addresses design and implementation of a strapdown boatboard camera stabilizer. A two degree of freedom(DOF)(pan/tilt) robot performs the stabilization task. The main problem is divided into two subproblems dealing with attitude estimation and attitude control. It is assumed that exact estimate of the boat movement is available from an attitude estimation system. Estimates obtained in this way are carefully transformed to robot coordinate frame to provide desired trajectories, which should be tracked by the robot to compensate for the boat movements. Such a practical robotic system includes actuators with fast dynamics(electrical dynamics) and has more degrees of freedom than control inputs. Backstepping method is employed to deal with this problem by extending the control effectiveness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.687-690
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• 2000

Lately, many studies have been progressed for the protection human's lives and property as holding in check accidents happened by human's carelessness or mistakes. One part of these is the development of an autonomouse vehicle. General control method of vision-based autonomous vehicle system is to determine the navigation direction by analyzing lane images from a camera, and to navigate using proper control algorithm. In this paper, characteristic points are abstracted from lane images using lane recognition algorithm with sobel operator. And then the vehicle is controlled using two proposed auto-steering algorithms. Two steering control algorithms are introduced in this paper. First method is to use the geometric relation of a camera. After transforming from an image coordinate to a vehicle coordinate, a steering angle is calculated using Ackermann angle. Second one is using a neural network algorithm. It doesn't need to use the geometric relation of a camera and is easy to apply a steering algorithm. In addition, It is a nearest algorithm for the driving style of human driver. Proposed controller is a multilayer neural network using Levenberg-Marquardt backpropagation learning algorithm which was estimated much better than other methods, i.e. Conjugate Gradient or Gradient Decent ones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.303-308
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• 2014

This paper deals with interface design of a university webzines that to search through an internet portal site Naver. It was obtained the following conclusions. First, university webzines are using a hypertext link to such images, text, movie. Second, it could be seen that mainly been using block grid, the module grid, and a transformed layout of 2 tier grid. Third, Seoul woman's University, Kyungpook National University, and Korea Maritime University's webzines found that layout, color, user-friendly access the structure. Fourth, webzine was used the text or image a link, search function, site map, icon, favorites, quick menus, navigation bars, and rollover menu. Last, university webzines were shown to contribute mere to the enhancement of its value as a promotional medium.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.139-149
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• 1998

There are some problems in robot navigations with a single kind of sensor. We propose a system that takes advantages of both CCD camera and ultrasonic sensors for the concerning matter. A coordinate extraction algorithm to avoid obstacles during the navigation is also proposed. We implemented a CCD based vision system at the front part of the vehicle and did experiments to verify the suggested algorithm's availability. From experimental results, the error rate was reduced when a CCD camera was used rather than when only ultrasonic sensors were used. Also we can generate path to avoid those obstacles using the measured values.

• Imaging Science in Dentistry
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• v.44 no.2
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• pp.155-160
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• 2014

Purpose: The purposes of this study were to develop a workstation computer that allowed intraoperative touchless control of diagnostic and surgical images by a surgeon, and to report the preliminary experience with the use of the system in a series of cases in which dental surgery was performed. Materials and Methods: A custom workstation with a new motion sensing input device (Leap Motion) was set up in order to use a natural user interface (NUI) to manipulate the imaging software by hand gestures. The system allowed intraoperative touchless control of the surgical images. Results: For the first time in the literature, an NUI system was used for a pilot study during 11 dental surgery procedures including tooth extractions, dental implant placements, and guided bone regeneration. No complications were reported. The system performed very well and was very useful. Conclusion: The proposed system fulfilled the objective of providing touchless access and control of the system of images and a three-dimensional surgical plan, thus allowing the maintenance of sterile conditions. The interaction between surgical staff, under sterile conditions, and computer equipment has been a key issue. The solution with an NUI with touchless control of the images seems to be closer to an ideal. The cost of the sensor system is quite low; this could facilitate its incorporation into the practice of routine dental surgery. This technology has enormous potential in dental surgery and other healthcare specialties.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.464-467
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• 1995

Autonomous Mobile Robot(AMR) is a field of study which is under active research along with rapid development of the engineering technology. The main reasons for the high interest in AMR are because of its ability to change work space freely and its capability to replace human being for difficult and dangerous jobs. Also the fact that AMR provides a variety of research fields, such as path planning, navigation algorithm, sensor fusion, image processing, and controller design is part of the reason for its popularity. But relatively few researches are concerned with controller. So in this paper, a control strategy of mobile robot with nonholonomic constraint for tracking ordered discontinuous motion is proposed. The proposed control strategy has been designed as a state feedback shape to allow the AMR to obtain continuous velocity and track the path which is composed of discontinuous motions. In order to design such controller, 3 states have been reduced to 2 states through coordinate projection. These ideas are tested for validity through simulation and simulation result is compared with experiments result.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.298-303
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• 2014

In this paper, we proposed a robust object extraction and tracking algorithm in the IR image sequence acquired in the sea environment. In order to extract size-invariant object, we detect horizontal and vertical edges by using DWT and combine it to generate saliency map. To extract object region, binarization technique is applied to saliency map. The correspondences between objects in consecutive frames are defined by the calculating minimum weighted Euclidean distance as a matching measure. Finally, object trajectories are determined by considering false correspondences such as entering object, vanishing objects and false object and so on. The proposed algorithm can find trajectories robustly, which has shown by experimental results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.599-606
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• 2014

Since the accuracy of Global Positioning System (GPS)-based vehicle positioning system is significantly degraded or does not work appropriately in the urban canyon, the integration techniques of GPS with Inertial Navigation System (INS) have intensively been developed to improve the continuity and reliability of positioning. However, its accuracy is degraded as INS errors are not properly corrected due to the GPS signal blockage. Recently, the image-based positioning techniques have been started to apply for the vehicle positioning for the advanced in processing techniques as well as the increased the number of cars installing the camera. In this study, Single Photo Resection (SPR), which calculates the camera exterior orientation parameters using the Ground Control Points (GCPs,) has been integrated with the INS/GPS for continuous and stable positioning. The INS/GPS/SPR integration was implemented in both of a loosely and a tightly coupled modes, based on the Extended Kalman Filter (EKF). In order to analyze the performance of INS/SPR integration during the GPS outage, the simulation tests were conducted with a consideration of factors affecting SPR performance. The results demonstrate that the accuracy of INS/SPR integration is depended on magnitudes of the GCP errors and SPR processing intervals. Additionally, the simulation results suggest some required conditions to achieve accurate and continuous positioning, used the INS/SPR integration.