• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.5
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• pp.725-731
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• 2013

In This paper, through simulation, proposes a system which makes it possible for freely moving multiple agents with ultrasonic receivers to estimate their own position by themselves using the ultrasonic signals sequentially emitted from multiple ultrasonic transmitters. This system possesses an advantage that there is no limit in the number of agents existing in the space covered by more than three transmitters fixed at proper locations. Hence, the proposed system can be utilized effectively in position tracking control of multiple robotic agents system and motion capturing system.

• Journal of the Korea Computer Industry Society
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• v.9 no.3
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• pp.121-128
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• 2008

This paper suggested a location-based traffic information service system using TPEG and GIS. Measurement technique, location server, applied service technique, and linkage technique with database were used to provide the location-based traffic information service. In particular, TPEG-RTM includes location information and load traffic message. The location information to be included in each message displayed a specific point, section or region limit of the load. Actually, because it was impossible to receive data using TPEG receiver, a proposed program included in this paper was used to produce an arbitrary database and read it, Also, TPEG event happened time was indicated on the map for matching test of a TPEG message and WGS84 coordinate, and finally it was verified with art example of a vehicle approaching to an event happened place.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.999-1004
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• 2010

Most of campus vehicle management systems, so far, simply manages coming in or go out of vehicles, issuing a parking tickets. Recently some of them use RFID tags to count total numbers of cars in the campus, excluding exact parking position management. In this paper we propose a new campus vehicle management system using wireless sensor network location management scheme. This system adopts RSSI based location management method with some performance improvement technique. According to the experimental result, this proposed scheme can be used to implement an effective campus vehicle management system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.575-576
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• 2016

Recently utilizing GPS (Global Positioning System) technology has become the research in progress to improve the accuracy. However, if you encounter problems when you receive a satellite signal reception accuracy it is also significantly lowered. In this paper, we designed a system that combines the GPS technology and the GIS (Geographic Information System) technology, which provides information about the specified location to increase the accuracy. Compare the specified location and the user's location information to determine whether the user enters for the location. Accordingly, is utilized by the GIS technique considered to make improve the accuracy of the location information even when there is interference in the received satellite signal, the user receives a service specified location.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.181-188
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• 2013

In this paper, we present a system design for location determination inside the ship. Since the GPS signal can not be received in the interior of the large vessel, we use the vessel wireless AP (Access Point) RSSI (received signal strength indication) to accurately measure the position. We convert the RSSI for the 3 AP's into distance through the Friis formula and get the location through triangulation. The signal strength varies irregularly due to noise making it difficult to obtain the exact location. Thus Kalman filter is used to real-time position correction, that is store in a server database.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.149-155
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• 2009

The frequency is widely used to measure the distance. In the warehouse, however, the frequency is apt to be interrupted by various unmade stuffs and cannot be easily applied to that kind of environment. This study will suggest the method to localize a worker in the warehouse exactly with calculating the time difference of arrival from the base position to a node or between each node and with 3-points pin pointer. This study will propose the localizing method using RFID tag and analyze the result using the suggested method. Also, the efficiency of suggested method will be increased with the simulation based on the information from the RFID tag.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1291-1298
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• 2023

Surveillance reconnaissance sensor network is used for surveillance in wartime and area of operation. In this paper, we propose a target localization method using the detection signal strength of seismic sensors. Relay equipment calculates the target location using coordinate information and detection signal strength of the seismic sensors. Target localization error deviation due to environmental factors was minimized by subtracting the dynamic offset when calculating the target location. Field test shows improvement of target localization through reduction of errors. The average error was decreased to 3.62m. Up to 62% improved result was obtained compared to weighted centroid localization method.

• Journal of Korea Spatial Information System Society
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• v.4 no.1 s.7
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• pp.27-37
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• 2002

Ideas providing an optimal car route using current traffic condition, maintaining the current location and the history of driven route of a car in the main central office, in where GPS signals transmitted from the driving cars are received, have been proposed. Since GPS signals occurred in certain time interval instead of all GPS signals are transmitted from the car due to the cost of transmission, an algorithm that is able to recover the missing GPS signals is required. In this paper, an efficient algorithm, which finds the driven route and the current location of a car fast, is proposed. To verify the efficiency of the proposed algorithm, it is applied to the various real GIS map and it turns out to be very effective.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.63-66
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• 2011

본 논문에서는 현재 3GPP에서 진행되고 있는 차세대 이동통신 기술 표준, 즉 LTE 시스템의 하향링크 전송방식의 수신성능을 향상시키기 위해 기지국(BS)과 단말(MS) 사이에 릴레이(RS) 설치를 제안하고, BS의 위치와 설치된 RS의 거리를 각각 500m, 1000m로 하고 RS의 전송방식을 OFDMA와 SC-FDMA를 선택함으로써 수신성능을 높이기 위한 연구를 수행하였다. 연구결과 RS의 위치가 BS와 가까울수록 RS에서는 SC-FDMA를 사용하는 것이 좋게 나왔고, 반대로 BS와 RS의 거리가 멀어질수록 RS에서는 OFDMA를 사용하는 것의 성능이 좋은 것으로 나왔다. 또한 BS와 MS 거리의 중심지역에서는 그 상황에 맞는 전송방식을 사용함으로써 시스템의 수신성능을 향상시킬 수 있었다.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.191-197
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• 2011

In this paper, we have designed an integrated triplexer which is the basic component for a FTTH(Fiber To The Home) system which can transmit CATV and voice/data at the same time in a single fiber. The integrated triplexer can be fabricated with a novel technique of "Micro-Block Stacking (MBS)" method which automatically aligns the optical components in the optical beam pass using accurate ceramic holders. We analyze the displacement of the optical focus according to the tolerances of the component dimensions and the assembly process using code V simulator. For the transmitter, the most serious shift of the focal points is caused by the displacements of the LD spot. So the focal point moves up to $72{\mu}m$ from the center point for ${\pm}25{\mu}m$, ${\pm}25{\mu}m$, ${\pm}30{\mu}m$ displacements. For the receiver the most serious shift of the focal points is caused by the displacements of a 0.8mm ball lens (for the analog receiving part) and a micro ball lens (for the digital receiving part), and the focal point moves up to $55{\mu}$ for ${\pm}55{\mu}m$, ${\pm}5{\mu}m$, ${\pm}55{\mu}m$ micro ball lens displacements.