• Journal of the Korean Institute of Navigation
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• v.20 no.3
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• pp.127-135
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• 1996

This study investigated the correlation of physique factor( standing height, body weight, chest girth, body surface ) and vital capacity upon records of swimming discipline at sea water. The subjects are 194 sophomore students of Korea Maritime University who participated in the swimming discipline. The swimming records were divided into three groups - higher, middle and lower group. The results from this investigation are as follow ; 1. The standing height was above the average on the A, B+ record, body weight was above on the A+, A record, and vital capacity was above on the A+, A, B+, C record respectively. 2. The standing height, body weight, chest girth, body surface, vital capacity was significantly correlated between record P < 0.05 and P < 0.01. Therefore the higher record group has better physique factor and vital capacity than the middle or lower record group. 3. The standing higher of the higher record group was significantly correlated with body weight(0.514), body surface(0.768) and vital capacity(0.427), and body weight was significantly correlated with chest girth(0.525), body surface(0.940) and vital capacity. This standing heiht of the middle record group was sigificantly correlated with body weight(0.509) and body surface(0.779), and body weight was significantly orrelated with chest grith(0.618) and body surface(0.927). The standing height of the lower record group was significantly correlated with body weight(0.595), chest grith(0.363), body surface(0.802) and vital capacity(0.250), and body weight was significantly correlated with chest grith(0.678) and body surface(0.952).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.505-514
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• 2014

The effects of reflected wave of the sea on pseudolite ranging accuracy are analysed in this paper, when a pseudolite navigation system is used for wide area outdoor applications such as aircraft and vessels positioning. Methods for minimizing the influence of sea surface reflection wave were proposed. The methods include the appropriate correlator in pseudolite navigation system through the correlation performance comparison analysis in receiver design, the use of the technology of multiple antennas, and locating the transmitting station antenna on an appropriate position. From the results of experiments, the method of locating the antenna position shows the most reliable performance against the effect of surface reflection wave. The analysis results of the ranging accuracy improvement are addressed, when the multipath caused by sea surface reflection exists.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1995.11a
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• pp.184-192
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• 1995

Although ship's draught information onboard is substantial for both the safety of navigation and the estimation of loaded cargoes its accuracy depends in traditional surveying method on the skillfulness of observers and the condition of the sea surface round the vessel. To obtain more accurate information accessibly measuring instruments with sophisticated sensors such as mechanical electronic and ultrasonic transducers have been developed. however they have still limitation in accuracy and in making up a system due to the complexity of processing signal. In this paper we propose a he technique for analyzing ultrasonic pulse signal in order to improve the measurement accuracy and simplify a remote sensing system of draught by ultrasonic waves. This technique is useful for measuring draught being considered the influence of sea surface fluctuation and for transferring its data briefly to required equipment in integrated bridge system.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.469-472
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• 2023

If temperature management is required in factory or environmental monitoring, temperature can be measured by connecting various sensors wired or wirelessly. Surface acoustic wave sensors measure temperature using changes in acoustic waves on the sensor surface according to temperature, and are useful for wireless networks. In this paper, in order to build a wireless temperature measurement system in the 900 MHz frequency band, the temperature characteristics of the passive SAW sensor were measured, and the analysis and removal of multipath reflection wave effect inside the high temperature chamber were conducted. The resonant frequency of the SAW sensor was measured, and radio transmission/reception and multipath reflected wave removal techniques were proposed in the shielded chamber.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.357-359
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• 2022

Autonomous decision-making is key to safe and efficient marine autonomy, as global marine industry comprises over 90 percent of the world's cargo transportation. Challenges of the real-world validation in the aquatic domain limits the wide-spread of ASVs despite their promising societal impacts. We propose and demonstrate the real-world validation platform and comprehensive algorithm steps. Such a framework will serve as a more explainable and reliable decision-making system of ASVs as well as autonomous vehicles in other domains.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.682-687
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• 2013

Navigation is a crucial capability for all types of manned or unmanned vehicles. However, vehicle navigation in underwater environments still remains a challenging problem since GPS signals for position fixes are not available in the water. Terrain-referenced underwater navigation is an alternative navigation technique that utilizes geometric information of the subsea terrain to correct drift errors due to dead-reckoning or inertial navigation. Terrain-referenced navigation requires the description of an undulating terrain surface as a mathematical function or table, which often leads to a highly nonlinear estimation problem. Recently, PFs (Particle Filters), which do not require any restrictive assumptions about the system dynamics and uncertainty distributions, have been widely used for nonlinear filtering applications. However, PF has considerable computational requirements which used to limit its applicability to problems of relatively low state dimensions. This study proposes the use of a Rao-Blackwellized particle filter that is computationally more efficient than the standard PF for terrain-referenced underwater navigation involving a moderate number of states, and its performance is compared with that of the extended Kalman filter algorithm. The validity and feasibility of the proposed algorithm is demonstrated through numerical simulations.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.183-189
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• 2020

In emergency rescue situations, the localization accuracy of the rescue requestor is a very important factor in determining the success or failure of the rescue. Indoors where Global Navigation Satellite System (GNSS) is not operated, there is no choice but to use Wi-Fi or LTE signals. However, the performance of the current emergency rescue system utilizing those RF signals is exceedingly low. In this study, the effectiveness of the surface correlation technology using the accumulated signal pattern of RF signals was verified in relation to the emergency localization technology. To validate the proposed system, we configured and tested an emergency rescue scenario in multi-floors building. When the emergency rescue was requested, it was confirmed that the initial localization error was large owing to the short length of the accumulated signal pattern. However, the localization error decreased over time, which eventually led to the accurate location information being delivered to the rescuer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.134-135
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• 2013

In this study, the physical properties and antifouling were investigated to make the Marine growth antifouling coatings by blending of synthesized silicone resin and pigment with a low surface tension. To examine the film properties and foul release of the prepared coatings, film specimens were prepared with the prepared coatings and anti corrosion coatings. The test results showed that the silicone type antifouling coatings had very excellent antifouling properties rather than any other coatings because of the coating films had followed the low surface tension and elasticity, and prevention of adhesion for marine growth and mechanical adhesions.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.24-30
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• 2017

Obstacle defines all fixed and mobile objects, or parts thereof, that are located on an area intended for the surface movement of aircraft or extend above a defined surface intended to protect aircraft in flight or stand outside those defined surfaces and that have been assessed as being a hazard to air navigation. Aircraft operations are based on electronic supporting systems using radio frequencies to assist pilots. These frequencies can receive outside interference that change their courses or power, such as distortion, attenuation or reinforcements by an obstacle. This is a preliminary case study that shows the relation of instrument flight procedures and the degree of interferences introduced by a planned obstacle, which is a main bridge post, within the service volume of the radio navigation aids. For the purpose of this study, the case airport's data and it's VOR/DME and ILS systems' limitations are analyzed, as well as the relation of interferences between the obstacle and navigation aides were reviewed with the internal regulations in Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.447-448
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• 2022

Studies on autonomous ships has received a lot of attention, recently. However, a study on autonomous navigation assistance service for Navigation Assistance Service(NAS) which is second item of Maritime Service Portfolio(MSP) suggested by IMO was not studied. Therefore, in this paper, we derive information items for autonomous navigation assistance service and research on a display system for displaying the items.