• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.643-647
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• 1990

Gunner primary sight(GPS) stabilization system lays line of sight(LOS) to find out a target and transmits informations to the fire control system (FCS). In a moving vehicle, accuracy of LOS and FCS depends on the design of GPS and servomechanism system. The heavy vibration of vehicle on the severe off-road environment degenerates the stabilization capability of GPS. In this study, to stabilize of elevation for GPS using the variable structure control, we derived the dynamic equation of GPS system and designed the variable structure controller. Computer simulation results fulfilled the static and dynamic stability of GPS using the variable structure control.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.124-131
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• 2005

This paper suggests LOS(Line-Of-Sight) guidance system of a surface vessel in straight-line navigation under ocean currents An LOS vector from the vessel to a point on the path between two way-points is decided and a heading angle is calculated to converge to follow the desired path based on the LOS vector This guidance system is called LOS guidance system. The suggested LOS guidance law has parameters to be properly chosen according to navigational environment. Parameters of LOS guidance system are optimized to reduce propulsive energy and/or position error between desired Position and present position of a ship using genetic algorithm which is a strong optimization algorithm with adaptational random search The effectiveness of the suggested LOS guidance system is assured through computer simulations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1028-1032
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• 1996

Stabilization performance of a sight stabilization system can be improved by proper selection of control algorithm and mechanism. In that aspect, in this paper, effects of an inertia balancer are studied. Parameters of the inertia balancer were obtained from the governing equation by assuming there is no external force and friction. Simulation and experimental results show that the inertia balancer contributes significantly to the stabilization of the line of sight(LOS). In particular, it was found that the inertia balancer is more effective as frequency of the disturbance increases.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.579-580
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• 2010

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.21-25
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• 2016

In this paper, we propose an algorithm for optimal selection of communications for smart lighting in heterogeneous networks. The smart lighting can be used for information communications and lighting simultaneously. To improve BER performance of smart lighting in heterogeneous networks, it adaptively selects a communication method among OCC, Wi-Fi, BLE based on distance between sensors and smart lightings, low power consumption for user requirements, operating time of smart lighting in Line-of-Sight(LOS)/Non-LOS channels. Thus, simulation results demonstrate effectiveness of the proposed algorithm contrary to baseline methods in LOS/NLOS channels.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.65-69
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• 2005

The theoretical propagation modes of radio waves in the area of Line of Sight(LOS) within Fresnel zone are searched for the available detection ranges in a Marine RFID (Radio Frequency Identification). The structural LOS model to Earth's curvature is proposed and, the calculation method of horizontal distance in a specific radio frequency is also considered in this work As studying results, it is found that the height of antenna to cover the detection ranges and the influences of detection ranges by weather environments can be analyse with the theoretical methods.

• Journal of Korea Multimedia Society
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• v.21 no.5
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• pp.583-591
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• 2018

With the development of ICT(Information and Communication Technology), the number of smart devices is rapidly increasing. LBS(Location Based Service) applications that provide user's location based service are used in various fields. There is also a growing demand for indoor precision positioning technology to provide seamless services. In this paper, we propose an indoor positioning system that estimates the location of a smartphone user. The proposed algorithm determines whether the received signal is LOS(Line-of-Sight) or NLOS(Non-Line of-Sight) in order to decrease multipath effect by the indoor environment. The proposed positioning algorithm is very simple and requires only the AP(Access Point) coordinates. In addition, it requires only two APs for estimating the location of a smartphone user. The proposed algorithm is a practically applicable technology without any additional hardware and kernel modification in the smartphone. In the experiment results, the reliability of the positioning system was found to be within 0.83 m.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.4
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• pp.363-368
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• 2005

This paper proposes an LOS(line-of-sight) guidance system of a ship for path following. From the viewpoint of a control configuration, guidance is a special type of compensation algorithm that is placed in front of the controller to accomplish navigational objects. A guidance system generates a reference trajectory for trajectory tracking or path control and decides the desired velocity, position and heading angle. A control system executes commands based on a reliable guidance law during navigation. An LOS vector from the vessel to a point on the path between two way-points in straight-line navigation or a point among turning circle in turning navigation is selected, and then a heading angle is calculated to converge the desired path based on the LOS vector. The LOS guidance law is defined for the straight-line and the turning circle, respectively. The effectiveness of the suggested LOS guidance system is assured through computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1240-1245
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• 2011

In this paper, channel modeling and analysis of wireless visible light communication(VLC) were studied in indoor circumstance. Photons emitted from LED straightly moved and navigated within indoor, after that a part of photons reached on PD via LOS(Line Of Sight) or NLOS(None Line Of Sight). These received signals had characteristics of delay profile and attenuation, which was multiple-path fading. In this paper, computer simulation of VLC channel was executed under the condition that two LEDs were used for transmitter and three PDs were located at different positions of the 20*8*2.3m sized indoor. BER performance simulation was excuted based on the characteristics of each VLC channel.

• Journal of Electrical Engineering and Technology
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• v.2 no.1
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• pp.123-128
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• 2007

SPWPM traditional software development is surveyed and essential problems are investigated on the basis of system wireless link considerations. This paper presents the current state software planning tools for wireless LAN link optimization. The software directory is based on combination of MatLab and MapInfo software and measurement which gives the best grouping parameters to build up the software development. Among the requirements assumed, the WLAN site selections must be Line-of-sight (LOS) or near line of sight (NLOS) field strength prediction for either point to point or point to multi points. The results obtainable the out put of the program include two-dimensional (2D) and three dimensional (3D) plots for creating the link; design parameters through GUI representing the height and location for each antenna is depending on K-factor of the area and transmit antenna location.