• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.99-107
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• 2016

Korea has been known as volcanic disaster free area. However, recent surveying result shows that Baekdu mountain located in northernmost in the Korean peninsula is not a dormant volcano anymore. When Baekdu mountain is erupting, various damages due to the volcanic ash are expected in South Korea area. Especially, volcanic ash in the air may cause big aviation accident because it can hurt engine or gauges in the airplane. Therefore, it is a crucial issue to interrupt airplane navigation, whose route is overlapped with volcanic ash, after predicting three dimensional dispersion of volcanic ash. In this paper, we deals with 3D visualization techniques for volcanic ash dispersion prediction results. First, we introduce the data acquisition of the volcanic ash dispersion prediction. Dispersion prediction data is obtained from Fall3D model, which is volcanic ash dispersion simulation program. Next, three 3D visualization techniques for volcanic ash dispersion prediction are proposed. Firstly proposed technique is so called 'Cube in the Air', which locates the semitransparent cubes having different color depends on its particle concentration. Second technique is a 'Cube in the Cube' which divide the cube in proportion to particle concentration and locates the small cubes. Last technique is 'Semitransparent Volcanic Ash Plane', which laminates the layer, whose grids present the particle concentration, and apply the semitransparent effect. Based on the proposed techniques, the user could 3D visualize the volcanic ash dispersion prediction results upon his own purposes.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.35-40
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• 2010

Skyline extraction in mountainous images which has been used for navigation of vehicles or micro unmanned air vehicles is very hard to implement because of the complexity of skyline shapes, occlusions by environments, dfficulties to detect precise edges and noises in an image. In spite of these difficulties, skyline extraction is avery important theme that can be applied to the various fields of unmanned vehicles applications. In this paper, we developed a robust skyline extraction algorithm using two-scale canny edge images, topological information and location of the skyline in an image. Two-scale canny edge images are composed of High Scale Canny edge image that satisfies good localization criterion and Low Scale Canny edge image that satisfies good detection criterion. By applying each image to the proper steps of the algorithm, we could obtain good performance to extract skyline in images under complex environments. The performance of the proposed algorithm is proved by experimental results using various images and compared with an existing method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.407-412
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• 2011

Even though KMA(Korea Meteorological Administration) has been doing WE-FAX service in past 40 years, most of korean ship's officers use Japan/USA WE-FAX instead of KMA WE-FAX during passage in the NW Pacific. In this regards, the authors carry out the research on the improvement of KMA WE-FAX service, examining the officers's opinions to KMA WE-FAX service along with comparing Korea, Japan & USA synoptic weather charts. As a result, it is suggested that (1) Have KMA WE-FAX service known to the officers in the course of education and training, (2) Persuade ocean-going ships to participate VOS to provide more accurate weather charts. (3) Provide additional weather charts such as Wave analysis, Surface forecast and put useful weather informations on weather charts to enhance navigational safety.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.570-576
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• 2010

This paper can be used for GPS air navigation study on integrity monitoring algorithm as, the projected horizontal plane using GPS pseudorange residuals for fault detection satellites were suspected. Failure to remove the detected suspicious satellite, compare with threshold which is calculated using satellite deployment (PDOP) and determine whether the failure is presented. The theory that horizontal projection of the satellite failure residuals greater than residual of normal satellite is proved mathematically. Comparison with horizontal projection residuals are likely to malfunction in the satellite were presented. To evaluate the proposed algorithm, bias fault insert into GPS pseudorange, and compare with conventional parity space method about fault detection and isolation capability.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.05a
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• pp.59-64
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• 2000

Active radar reflector may be less familiar, since their uses have been limited to military applications, especially the enhancement of the effective radar cross-sections of missile test range in the drone aircraft and missiles. Perhaps the most widely-blown applications of radar transponders are Identification Friend or Foe(IFF) and its civilian counterpart, secondary surveilliance radar for Air Traffic Control(ATC), and most recently, as Search And Rescue Transponder(SART) in the Global Maritime Distress and Safety System(GMDSS). Since it happens frequently accidents on the sea, the problems of the contamination more seriously considered. The conventional navigation buoy and utilities are not sufficient to maintain the safety of the sea and thus new structured concept must be considered. Therefore, this paper propose and implement the active radar reflector with a enhanced structure. The results are shown that the performance of the system is significantly improved comparing with the conventional utilities.

• The KIPS Transactions:PartA
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• v.14A no.5
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• pp.255-262
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• 2007

Physically-based researches on simulating helicopter motions have been achieved in the field of aeronautics, aerodynamics and others. These results, however, have not been appled in the computer graphics area, mainly due to their complex equations and heavy computations. In this paper, we propose a dynamics model of helicopter rotor blades, which would be easy to implement, and suitable for real-time simulations of helicopters in the computer graphics area. Helicopters fly by the forces due to the collisions between air and rotor blades. These forces can be interpreted as the impulsive forces between the fluid and the rigid body. Based on these impulsive forces, we propose an approximated dynamics model of rotor blades, and it enables us to simulate the helicopter motions using existing rigid body simulation methods. We compute forces due to the movement of rotor blades according to the Newton's method, to achieve its real-time computations. Our prototype implementation shows real-time aerial navigation of helicopters, which are murk similar to the realistic motions.

• Journal of Multimedia Information System
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• v.4 no.4
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• pp.195-204
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• 2017

Mobile robots are used for years as a valuable research and educational tool in form of available open-platform designs and Do-It-Yourself kits. Rapid development and costs reduction of Unmanned Air Vehicles (UAV) and ground based mobile robots in recent years allowed researchers to utilize them as an affordable research platform. Despite of recent developments in the area of ground and airborne robotics, only few examples of Unmanned Surface Vehicle (USV) platforms targeted for research purposes can be found. Aim of this paper is to present the development of open-design USV drone with integrated multi-level control hardware architecture. Proposed catamaran - type water surface drone enables direct control over wireless radio link, separate development of algorithms for optimal propulsion control, navigation and communication with the ground-based control station. Whole design is highly modular, where each component can be replaced or modified according to desired task, payload or environmental conditions. Developed USV is planned to be utilized as a part of the system for detection and identification of marine and lake waste. Cameras mounted to the USV would record sea or lake surfaces, and recorded video sequences and images would be processed by state-of-the-art computer vision and machine learning algorithms in order to identify and classify marine and lake waste.

• Journal of Hydrogen and New Energy
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• v.22 no.2
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• pp.152-160
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• 2011

The electromagnetic characteristics of FCEVs (fuel cell electric vehicles) are much different from the existing combustion engine cars as well as hybrid, plug-in-hybrid, and pure electric vehicles due to the high voltage/current generated by a fuel cell stack which uses a compressed hydrogen gas reacted with oxygen. To operate fuel cell stack efficiently, BOP (Balance of Plant) which is consisted of many motors in water pump, air blower, and hydrogen recycling pump as well as inverters for these motors is essential. Furthermore, there are also electric systems for entertainment, information, and vehicle control such as navigation, broadcasting, vehicle dynamic control systems, and so on. Since these systems are connected by high voltage or general cables, EMC (Electromagnetic compatibility) analysis for high voltage and general cable of FCEV is the most important element to prevent the possible electric functional safety errors. In this paper, electromagnetic fields by high voltage and general cables for FCEVs is studied. From numerical analysis results, total time harmonic electromagnetic field strength from high voltage and general cables have difference of 13~16 dB due to ground effect by impedance matching. The EMI results of FECV at 10 m distance shows difference of 41 dB at 30 MHz and 54 dB at 230 MHz compared with only general cable routing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1251-1258
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• 2002

The weather FAX machine is the one of necessary of safety navigation for ship. which is the machine which make the weather image by the receiving radio signal which is modulated using FSK method and transmitted on air by coast station. after Coast station scan the weather image and broadcast the image with black dot to 1500Hz and white dot to 2300Hz using FSK modulation. This paper implement weather fax machine using only general IBM-PC by software. By using IBM-PC we can make some good functions like print, edit, save etc. The modulated signal from SSB go into RS232C port via photo coupler not to give damage to PC. by using Timer Interrupt and RS232C serial interrupt, we can measure signal frequency and remake weather image. This paper use only IBM-PC with general SSB receiver which is widely spread on the ship. so this is very economic and possible to implement mutifunctions.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.30-34
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• 2013

Prevention of exhaust gas back flow becomes a great interest to shipyards and shipowners in large container carriers because exhaust gas pollutes cargoes, flows back into the deck house and the engine room area through fresh air intakes and fan rooms, gives harmful damages to the crew's health and also gives thermal damages to electric equipments on the navigation deck. The phenomena of exhaust gas back flow has been studied with the analysis of sea trial records and wind tunnel tests and the height of the exhaust gas pipe, the front area of the deck house, the inflow speed and the position of the radar mast platform has been confirmed as the principal factors of exhaust gas back flow phenomena. The simple empirical formula to estimate exhaust gas back flow phenomena and the design guidances of exhaust gas related structures on deck has been introduced. In future, parametric studies for the exhaust gas back flow factors will be carried out with the CFD analysis. The results of this study will be the guide for development of the prevention method of exhaust gas back flow phenomena for large container carriers.