• Journal of Advanced Navigation Technology
• /
• v.14 no.3
• /
• pp.336-342
• /
• 2010

GPIR(GPS Position Information Revision) system is a new concept of GPS system which utilizes database containing the location of taking a picture by the existing GPS, an angle between a camera and a subject and the location information of buildings and minimizes the GPS's own margin of error and there by provides the services, such as location-guiding via GPS and way-guiding via navigation in an exact and precision way more than before. GPIR system comprehends the location of taking photos via GPS information saved in G-files, searches database in the direction of taking a photo at a photo-taking position via location information and the photo-taking directional angle. And GPIR system corrects the GPS information searched to the location of a subject, again saves such information in a G-file and is ready for receiving more detailed location of the subject. This study explores into the design and development of a receiver which a GPIR user is able to utilize its system as well as the design of the receiver's prototypes.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.4
• /
• pp.368-373
• /
• 2010

A new indoor mobile robot localization method is presented. Robot recognizes well designed single color landmarks on the ceiling by vision system, as reference to compute its precise position. The proposed likelihood prediction based method enables the robot to estimate its position based only on the orientation of landmark.The use of single color landmarks helps to reduce the complexity of the landmark structure and makes it easily detectable. Edge based optical flow is further used to compensate for some landmark recognition error. This technique is applicable for navigation in an unlimited sized indoor space. Prediction scheme and localization algorithm are proposed, and edge based optical flow and data fusing are presented. Experimental results show that the proposed method provides accurate estimation of the robot position with a localization error within a range of 5 cm and directional error less than 4 degrees.

• Proceedings of the KSRS Conference
• /
• 2008.10a
• /
• pp.137-140
• /
• 2008

Recently many areas require wide field of view images. Such as surveillance, virtual reality, navigation and 3D scene reconstruction. Conventional camera systems have a limited filed of view and provide partial information about the scene. however, omni directional vision system can overcome these disadvantages. Acquiring 360 degree panorama images requires expensive omni camera lens. In this study, 360 degree panorama image was tested using a low cost optical reflector which captures 360 degree panoramic views with single shot. This 360 degree panorama image system can be used with detailed positional information from GPS/INS. Through this study result, we show 360 degree panorama image is very effective tool for mobile monitoring system.

• The Journal of the Acoustical Society of Korea
• /
• v.15 no.3E
• /
• pp.37-44
• /
• 1996

A new method for efficient modeling of the Head-Related Transfer Functions(HRTF's) without loss of any directional information is proposed. In this paper, the HRTF's were empirically measured in a real room and modeled as the ARMA models with common AR coefficients and different MA coefficients. To assess the validity of the proposed ARMA model, psychophysical tests show that the proposed ARMA model, in comparison with the conventional MA model, requires a small number of parameters to represent empirical HRTF's and improves the back-to-front confusions in sound-field localization. Thus, significant simplifications in the implementations of sound-field synthesis systems could be obtained by using the proposed ARMA model.

• Journal of the Korea Computer Graphics Society
• /
• v.6 no.4
• /
• pp.15-22
• /
• 2000

One of the main research trends in image based modeling and rendering is how to implement plenoptic function. For this purpose, this paper proposes a novel approach based on a set of randomly placed panoramas. The proposed approach, first of all, adopts a simple computer vision technique to approximate omni-directional depth information of the surrounding scene, and then corrects/interpolates panorama images to generate an output image at a vantage viewpoint. Implementation results show that the proposed approach achieves smooth navigation at an interactive rate.

• Journal of Korean Port Research
• /
• v.14 no.2
• /
• pp.199-207
• /
• 2000

In this study, as the preliminary step for developing an unmanned vehicle to deliver a container-box, we designed and implemented Automatic Guided Vehicle(AGV) Simulator for the purpose of Port Facilities Automation. It is preferable to research the intelligent AGV for delivery all day long. For complementing AGV simulator driving, we used multiple-sensor systems with vision, ultrasonic, IR and adapted the high-speed wireless LAN that satisfies the IEEE 802.11 Standard for bi-directional communication between main processor in AGV and Host computer. Here, we mounted on bottom frame in AGV Pentium-III processor, which combine and compute the information from each sensor system and control the AGV driving, and used the 80C196KC micro-controller to control the actuating and steering motors.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.20 no.2
• /
• pp.13-17
• /
• 2012

The solar storm generated by solar activity can be impact on earth in various area. If solar storm impact on Navaids system, it will be a serious problem for aviation and human safety. The impact analysis of solar strom on Navaids system are performed in three area, ILS, GPS navigation and radio communication for aviation. Analysis result show that Instrument Landing System(LLZ, GP, MB) and Navaids system(VOR, DME, Radar) are not impacted by the solar storm, but GPS system is impacted by solar storm. Also analysis result show that VHF/UHF radio system are not impacted by solar storm, but HF radio system is impacted by solar storm.

• Journal of Korean Port Research
• /
• v.8 no.1
• /
• pp.17-22
• /
• 1994

The wave interaction with flexible membrane such as PVC and fabrics is studied to prove its applicability to portable breakwaters. To obtain the wave exciting force acting on flexible membrane, eigen-function expansion method is employed. The effect of flexible is involved in body boundary condition in which x-directional displacement of membrane is obtained by solving the linear membrane equation. Displacement of membrane is assumed to be small compared to wavelength, therefore the tensile force of membrane remains constant. As the numerical examples, transmission and reflection coefficients according to the change of tensile forces are investigated. The hydrodynamic force on membrane, the dynamic tension in the mooring lines and the vertical displacement profile of membrane are also calculated. It is suggested that the flexible membrane can be used to engineering material for the future coastal/ocean applications.

• Journal of Advanced Navigation Technology
• /
• v.21 no.4
• /
• pp.353-358
• /
• 2017

In order to reduce the size of the previous stepped slot antenna for UWB applications(3.1 ~ 10.6 GHz) to half, an open ended stepped slot antenna is proposed. The proposed antenna consists of a stepped slot etched on the ground plane as radiation part and a microstrip feed-line with rectangular patch on the top plane for wideband impedance matching. The proposed antenna is designed and fabricated on the FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm and size of $28.5{\times}32mm^2$. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) of the fabricated antenna is 7.99 GHz(3.01~11 GHz) which is sufficient to cover UWB band (3.1 ~ 10.6 GHz). In particular, it has been observed that antenna has a good omnidirectional radiation patterns and high gain over the entire frequency band of interest even though the size of the proposed antenna is reduced to half when compared with the previous antenna.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.3
• /
• pp.291-299
• /
• 2008

The present study is to estimate the effects of diffracted wave fields in a harbor and around harborentrance due to random waves, when a navigation channel is dredged in the vicinity of the a harbor entrance. The cross sections of harbor boundary are considered to be partial or full reflection in this study. The numerical simulation has been performed by the boundary element method, which is to discrete segments of pit- and harbor- boundary with the algorism of auto generated elements. The incident wave conditions are specified using discretized forms of the Mitsuyasu's frequency spectrum and directional function. The results of the present numerical simulation agreed well with those of the published experimental data. It is shown that the ratios of wave height reduction are about 20% for the case of fully reflecting boundary, and 10% for the case of partially reflecting boundary by the effect of placing a pit, respectively.