• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1206-1212
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• 2007

International Civil Aviation Organization(ICAO) adopted VOR(Very high frequency Omni-Range) as an international standard air navigation system in 1949 and recommended every country to make use of it in formulating air route and guiding take-off and landing of an aircraft. VOR is quite a useful navigation system so that more than 2,000 VORs are currently installed all over the world including 39 in the Republic of Korea; however, VOR signal could be easily affected by its circumstance like a mountainous area because it provides navigation information to an aircraft through AM and FM of VHF carrier. There are two types of VOR which are defined according to a design methode. Therefore this study intends to investigate which type of VOR is suitable for mountainous area. For that purpose, the performance of each CVOR and DVOR is measured and analyzed by using an aircraft equipped with measuring instruments. The analyzed result will be applied and utilized in selecting the VOR type, so it could be a feasible solution of problem related to the VOR relocation due to its insufficient performance in the future.

• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.1-7
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• 2008

International Civil Aviation Organization(ICAO) adopted VOR(Very high frequency Omni-Range) as an international standard air navigation system in 1949 and recommended every country to make use of it in formulating air route and guiding take-off and landing of an aircraft. VOR is quite a useful navigation system so that more than 2,000 VORs have been installed all over the world including 39 in Korea: however, VOR signal could be easily affected by its circumstance like a mountainous area because it provides navigation information through AM and FM of VHF carrier. Therefore this study intends to investigate how much VOR performance is affected by its circumstances. For this purpose, the performance of the 10 VORs influenced by 24 obstacles are measured and analyzed by using an aircraft equipped with measuring instruments. This study may give us a feasible solution of problems related to the VOR siting in the future.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.303-312
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• 2010

VHF Omnidirectional Radio range(VOR) is used as an aircraft navigational aid. The VOR is a short-range air navigation system providing aircraft with its bearing relative to the ground station. The accuracy of a VOR must be checked in accordance with the current ICAO, FAA and domestic regulations. The primary purpose of performing VOR station ground checks is to minimize the need for expensive flight checks by determining the amount and direction of any course bearing inaccuracies being transmitted. In this paper we present current and advanced way of monitoring of VOR system. We verify this way by field test of the monitoring and it is a high performance way to achieve an improvement in accuracy and an effect compared to present monitoring system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.564-569
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• 2010

VOR/DME is the short range radio navigation system for much of the world. The navigation with VOR/DME is used for a long time because of its reliability. It can be used for almost all civil aircraft. To simulate the small aircraft's autopilot system based on VOR/DME system, we developed a simulator by using SIMULINK. The output panel of the simulator was developed according to the cockpit instrument of an actual aircraft. To verify the performance of the simulator several scenarios were planned. And we showed that the simulator performed well.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.496-504
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• 2009

This paper presents a recognition performance of VOR (Vestibular-Ocular Reflex) based vision tracking system for mobile robot. The VOR is a reflex eye movement which, during head movements, produces an eye movement in the direction opposite to the head movement, thus maintaining the image of interested objects placed on the center of retina. We applied this physiological concept to the vision tracking system for high recognition performance in mobile environments. The proposed method was implemented in a vision tracking system consisting of a motion sensor module and an actuation module with vision sensor. We tested the developed system on an x/y stage and a rate table for linear motion and angular motion, respectively. The experimental results show that the recognition rates of the VOR-based method are three times more than non-VOR conventional vision system, which is mainly due to the fact that VOR-based vision tracking system has the line of sight of vision system to be fixed to the object, eventually reducing the blurring effect of images under the dynamic environment. It suggests that the VOR concept proposed in this paper can be applied efficiently to the vision tracking system for mobile robot.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.319-326
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• 2008

All over the world more than 2,000 VORs(VHF Omni-directional Ranges) including 39 in Korea are being operated for formulating air routes. But VOR reveals some difficulties in cost and time when relocating already an installed one due to its poor performance from the interference by its geometrically surrounding obstacles. DVOR(Doppler VOR) which is more popular than CVOR(Conventional VOR) has huge antennas and make it very difficult to assume a sufficient number of proper site candidates for permanent installation. This paper develops an efficient method for predicting proper site of DVOR installation by isolating transmitter from sideband antennas and counterpoise, making the transmitter easily moveable and verifying the performance of DVOR only with a transmitter and an antenna. The method was tested with a real flight measurement for DVOR performance around Gwangju Airport in Korea.

• Science of Emotion and Sensibility
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• v.18 no.1
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• pp.27-38
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• 2015

Vestibulo-ocular reflex (VOR) is a compensatory response of the extraocular muscles generated by vestibular signals to stabilize images on the retina during head/body movements. It has been reported that mismatches between retinal and vestibular information, which cause motion sickness or cybersickness, modify VOR. To investigate the characteristic changes of VOR in subjects experiencing cybersickness, we developed a low-cost, multi-purpose VOR measurement system using LabVIEW and Arduino. To test the applicability of the system, we performed two experiments. In Experiment 1, horizontal and vertical VORs of four participants were measured using a vestibular autorotation task. In Experiment 2, eight participants were exposed to a virtual navigation to measure changes of VORs as an index of cybersickness. We observed significantly greater head rotations and eye movements while the participants were exposed to the virtual navigation than to a static image. The results suggest that the present system can help understand the psychophysiological mechanisms of cybersickness symptoms.

• Journal of Advanced Navigation Technology
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• v.1 no.1
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• pp.59-69
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• 1997

In this paper, we construct a navigation geography database using R-tree, and develop a software for avionics systems such as VOR, ILS, DME, and NDB. First, we design the navigation geography database using R-tree, and construct a database for navigation aids facilities of every airport. In order to implement avionics software, we develop some calculating algorithms for distance, bearing, and deviation angle between an aircraft and a VOR station for VOR, and deviation angle from a LLZ, glide slope from a GP, and range of markers for ILS. The navigation geography database system is composed of map data manager which can construct and update the database, real-time searcher which provides information about the avionics system, geography database, and user interface.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.78-88
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• 2003

A novel adaptive error concealment technique is proposed using a variable operating region algorithm based on MPEG-4 coding. In the algorithm, a missing block is classified as flat or edge block based on local information from the surrounding blocks extracted using a Sobel operation in a variable operating region (VOR). In this case, the VOR is determined adaptively according to the number of edge directions in the missing block. 1;sing the classification, the flat blocks are then concealed by the Proposed mean based weighted bilinear interpolation (MWBLI) method, and the edge blocks by the boundary directional interpolation (BDI) method. Consequently, the use of the Proposed VOR improves the subjective performance in a curved edge region, while the adaptive processing based on block classification improves the objective performance. Experimental results confirmed that the proposed algorithm produced better results than conventional algorithms, both subjectively and objectively.

• The Journal of Korean society of community based occupational therapy
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• v.8 no.3
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• pp.91-106
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• 2018

The purpose of this paper is to review vestibulo-ocular reflex and vestibular rehabilitation for balace problem in elderly. Falling is a common problem associated with aging. Falling and the resulting consequences constitutes one of the most common and serious problems. Balance deficits are one of the top risk factors for falling. Three systems(visual, vestibular and somatosensory) need to be integrated and used to coordinate and control balance. During normal ambulation and head movement, the vestibulo-ocular reflex(VOR) stabilizes gaze, and helps to keep the image of the retina. There is a direct association between deficits in VOR and falls. Older adults have a decreased ability to enhance and suppress the VOR. Vestibular rehabilitation(VR) is an exercise-based group of approaches that began with the aim of central nervous system compensation. VR restores VOR gain and reduces error using repetitive movements of the head and eyes. Many researches showd balance and gait tests were superior in the VR group. It is considered this article helps to prevent elderly falling with vestibular rehabilitation.