• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.55-66
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• 2012

In wireless sensor networks, a positioning scheme is one of core technologies for sensor applications such as disaster monitoring and environment monitoring. The One of the most positioning scheme, called DV-HOP does not consider non-uniform sensor networks that are actual distributed environments. Therefore, the accuracy of the existing positioning scheme is low in non-uniform network environments. Moreover, because it requires many anchor nodes for high accuracy in non-uniform network environments, it is expensive to construct the network. To overcome this problem, we propose a novel sensor positioning scheme using density probability models in non-uniform wireless sensor networks. The proposed scheme consists of the density probability model using the deployment characteristics of sensor nodes and the distance refinement algorithm for high accuracy. By doing so, the proposed scheme ensures the high accuracy of sensor positioning in non-uniform networks. To show the superiority of our proposed scheme, we compare it with the existing scheme. Our experimental results show that our proposed scheme improves about 44% accuracy of sensor positioning over the existing scheme on average even in non-uniform sensor networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2968-2974
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• 2014

When lighting has installed indoor, we control lighting using human-detecting sensors for people who pass at night and places that are lack of quantity of light. However, malfunction can be caused by positions of inappropriate sensors, and in the case of passages of big buildings, it is a problem that even after a person pass, light apparatuses are turned on for a long time. In this paper, we propose lighting control system based on location positioning for energy saving that control lighting in accordance with passers's position through indoor location positioning. This system use the fingerprinting technology that is one of the location positioning technologies and RSSI data that is collected by a smart device. Using those, it can turn on only lightings that are included in the positioned location and reduce unnecessary power consumption. As a result of experiment, on condition that four people were existing and illumination was 308 lux, we assured reduction effect of 49 Wh.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5A
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• pp.801-808
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• 2001

본 논문에서는 전파의 도달시간을 이용한 이동통신 측위 시스템에서 사용되는 직접해, 최소 자승, 테일러 시리즈 그리고 찬 알고리즘의 성능을 분석하고, 각 알고리즘을 사용하여 계산된 결과를 궤환시켜 이동국의 위치를 재계산함으로써 보다 향상된 측위를 할 수 있는 결정 궤환 방법을 제안한다. 제안된 방법은 규칙 7셀 좌표와 불규칙 셀 좌표를 이용하여 이동국을 위치시킨 후, 전파의 지연시간에 따른 측위오차와 표준편차 그리고 각 알고리즘별 발산횟수를 조사하였으며, 실험결과 결정 궤환 방법을 사용하였을 경우 기존의 방법보다 향상된 성능을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1385-1388
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• 2006

위치기반서비스는 기본적으로 사용자의 위치를 파악해야 한다. 측위방법은 옥외용과 옥내용으로 구분되며, 옥외용에는 GPS 방법, 이동통신망을 이용한 방법, GPS와 이동통신망을 복합적으로 활용한 방법이 있고, 옥내용에는 적외선을 이용한 방법, 초음파를 이용한 ActiveBat과 Cricket, RF 신호를 이용한 RADAR가 있다. 기존의 옥외용 측위방법은 옥내에서는 사용이 제한되고, 기존의 옥내용 측위방법은 특수한 환경을 꾸며주어야 하는 단점이 있다. 본 논문에서는 이러한 단점을 보완한 방법으로 GPS 수신모듈과 무선LAN용 AP의 신호의 세기를 이용하여 사용자의 위치를 판단하는 옥내외 통합 측위시스템을 소개한다. 검증을 위해 제안하는 시스템을 구현해 보았으며, 실험 결과로 성능평가를 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.319-321
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• 2006

위치기반서비스는 기본적으로 사용자의 위치를 파악해야 한다. 측위방법은 옥외용과 옥내용으로 구분되며, 옥외용에는 GPS 방법, 이동통신망을 이용한 방법, GPS와 이동통신망을 복합적으로 활용한 방법이 있고 옥내용에는 RF 신호를 이용한 RADAR가 있다. GPS 방법은 미 국방성의 선택적 제공 때문에 큰 오차가 불가피하다. 한편 RADAR 방식은 오차가 작으나 옥내에서만 적용이 가능하다. 근래에는 대학 캠퍼스마다 무선LAN을 서비스하지 않는 곳이 없다. 본 논문은 무선LAN용 AP의 신호의 세기(RSSI)를 이용하여 정확도를 제고하는 옥외 측위방법을 제안한다. GPS를 이용한 측위와 제안하는 RSSI를 이용한 방법의 정확도를 실험적으로 비교한 결과를 소개하고, GPS 데이터와 RSSI를 함께 고려한 측위 방법과의 비교 결과도 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.86-89
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• 2016

실내 위치 인식 기술은 Wi-Fi, Bluetooth Low Energy 등 여러 기술을 통해 시도되어 왔으며, 실내 위치 인식 시스템의 상용화가 급증하는 추세이다. 대표적인 실내 측위 시스템인 Wi-Fi 기반 실내 측위는 고출력으로 넓은 범위에 서비스를 제공해주지만, 각 AP 마다 파워 출력이 다르기 때문에 위치 인식 측면에서의 오차가 발생하고, Bluetooth Low Energy 기반 실내 측위는 10m Cell 내에서는 정확한 인식이 가능하지반, 10m 거리 밖 오차는 매우 크다. UWB(Ultra Wide Band)[1][2][3]는 저전력으로, 3.1~10.6GHz의 대역올 이용하여, Wi-Fi의 10배 이상의 속도로 데이터를 전달한다. 이때, 데이터 전달에 사용되는 전파신호는 레이더 신호와 유사한 특징을 가져 거리측정에 사용될 수 있으며, 실내 측위 시 15cm 이내의 정확도를 가진다. 본 논문에서는 UWB의 광대역을 이용한 핑거프린팅과 정밀 측위를 위한 TDoA 기법을 이용한 정밀 실내 측위 알고리즘을 제안한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.601-606
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• 2019

The lenticular Location Based System is related to a location information technology. The system enables users to inform their location in real time wherever in a room, a building, a ship, a basement. In this paper, we analyze limitations and problems of the existing indoor Positioning System and propose a method of user-oriented location service. The proposed method consists of a lenticular sticker, a database(DB) acquisition and analysis technology. The proposed system can be used as an infrastructure to implement various indoor location-based services. In addition to improve user centered positioning accuracy through the development of location-based systems using indoor lenticular systems, it can be used in a disaster situation.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.239-251
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• 2007

This thesis is about the reduction of the power consumption in GPS embedded terminals with periodic position fix to improve the time delay of position determination. In order to improve time delay of position determination during the wireless terminal is powered on, it needs to be set such that it can be periodically recalibrated by the GPS and those recalibrated values need to be saved in the terminal's memory so that it can reduce the time delay from the request of location. By using the trace of the information that's been saved in the terminal's memory, it can be set so that it'll be easier to determine whether the wireless terminal has gone into buildings and have the capability of checking if it has gone into a specific building. Likewise, while the terminal is turned on, in order calibrate the location, it needs to continuously work the GPS engine which leads to a rapid decrease in terminal's idle time. This thesis proposes some solutions regarding these issues - reducing 20 ~ 30% of the battery consumption for GPS visible situation that can occur when the wireless terminal periodically calibrates its location to determine the in-building status, and extending the idle time of the terminal by flexibly using the suggested GPS calibration time method according to wireless terminal's mobility.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.345-347
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• 2016

Recently location based services is being expanded into the indoor service that can not access to the outdoor location informations, such as GPS. Thus, the research and development of an indoor positioning system with BLE(Bluetooth Low Energy) iBeacon technology has expanded. However, RSSI (Received Signal Strength Indicator) that is used as the distance information between the terminal and for positioning iBeacon signal has a problem in that distortion occurs, information such as the signal attenuation and the delay due to the characteristics of radio waves. In this paper, we propose a reliable method of verifying iBeacon signal with the signal distortion problems for reliable indoor positioning systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2579-2585
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• 2014

Location-Based Services can be defined as services that integrated a mobile network device's position with other information so as to provide added value to users. One of the most important elements in the LBS is the ability to locate objects. In this paper, the positioning techniques using radio signal were introduced, and the positioning principles and accuracies for LBS of smart phone were analyzed. As a result, the some techniques for improving user security were suggested.