• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.921-924
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• 2013

최근 무선랜 기반 실내 측위시스템을 활용하는 위치정보 서비스가 주목을 받고 있다. 기존 측위 방식에서는 주로 삼각측량 기법에 의존하여 사용자 단말의 위치를 측정하고 있으나, 실내 벽 등의 장애물로 인하여 정확한 측위가 어려울 뿐만 아니라 측위 오차가 크다는 문제점이 있다. 본 논문에서는 무선랜 기반 실내 측위시스템에서 방(room) 등의 블록(block) 단위로 사용자의 위치를 측정하는 방법을 제시한다. 실험 결과, 제안 방식은 기존 방식에 비해 측위 오차를 50% 이상 감소시킬 수 있음을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.364-367
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• 2007

We combined CC2431(Chipcon, Norway), as the platform for the Indoor Location Tracking, which follows Zigbee/IEEE802.15.4 standards in RSSI (Received Signal Strength Indicator) and Base Station Node and then, embodied Indoor Location Tracking System. CC2431 is composed of the Reference Node that transfer its current position at the designated place and the Blind Node. The Blind node receives the current position(X and Y coordinates) of the Reference Node fields which are being contiguous and also, calculates its current position and transfers it to the Base Station Node. The base station node is used for receiving the current position of blind node and passing its data to the PC as a gateway. We can make sure where is the Blind Node not only from the out-of-the-way place of the server side but from the outside in a real-time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.75-80
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• 2013

In this paper, We proposed a Optical Correlation for indoor positioning based LED-ID. The proposed Optical Correlation has a advantage to low-interference between spread code number sequences and LED-ID. it is applied a spread code to reduce the interference with additional information based LED-ID. The additional information is enable to detect in transmitted signal using auto correlation. Also we designed and implemented the Optical Correlation for clearly detecting the additional information. Simulations were performed to confirm the performance of BER and the power of additional information. Optical Correlation simulator to indoor positioning based LED-ID was implemented to prove a usefulness.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.202-204
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• 2015

본 논문에서는 기존 물류센터에서 활용되고 있는 물류관리시스템에 최근 부각되고 있는 ICT, 사물인터넷 기술을 융합하여 보다 스마트한 물류 추적 기능을 탑재한 물류추적시스템을 제안한다. 제안하는 물류추적시스템은 기존 물류관리에서의 단말기 단순 네트워크 연결이 아닌 블루투스 4.0기반 비콘 IPS(Indoor Positioning System) 서비스를 활용하여 제품의 생산부터 출고까지의 이동경로와 정확한 보관위치를 추적하여 효율적인 재고관리와 피킹이 가능하다. 또한 디바이스 단말기를 사물인터넷화 하여 다른 스마트팩토리 시스템과의 연동을 지원할 수 있을 것으로 기대한다.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.273-279
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• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.157-162
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• 2018

Tracking the location of patients in medical facilities is important to guarantee the patients' safety and to improve the service quality. Previous studies related to location tracking systems based on Bluetooth communication need numerous prerequisite information and multiple devices to improve the accuracy. In this paper, we propose a beacon-based space partition scheme that assigns different arrangement patterns of beacons to different spaces and composes groups with the similar value of RSSI to minimize prerequisite information and the number of beacons. The proposed scheme considers a pattern arrangement scheme to minimize intereference between neighbor patterns. We also verified the applicability of our scheme to monitor the patient location by using experimental results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2523-2529
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• 2014

Location estimation service can be provided outdoors using various location estimation system based on GPS. However, location estimation system is based on existing indoor resources as GPS cannot be used because of insufficient visible satellites and weak signals. The fingerprinting technique that uses WLAN signal, in particular, is good to use indoors because it uses RSSI provided by AP to estimate location. However, its accuracy may vary depending on how accurate data the offline stage used where the fingerprinting map is built. The study sampled various data at the stage that builds the fingerprinting map and suggested a location estimation system that enhances its precision by saving the data of high frequency among them to improve this problem. The suggested location estimation system based on majority sampling data estimates location by filtering RSSI data of the highest frequency at the client and server to be saved at a map, building the map and measuring a similar distance. As a result of the test, the location estimation precision stood at minimum 87.5 % and maximum 90.4% with the margin of error at minimum 0.25 to 2.72m.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3170-3175
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• 2009

In this paper, we developed u-Care service system using technologies of USN and LBS to help construct social welfare infrastructure and social safety net for lone seniors and handicapped people. This service not only monitors the in-house and outdoor activities of those disabled people but also sends the messages, whenever abnormal behaviors are detected, to the people related to them as well as the social welfare organizations and public safety institutions such as police and emergency services and etc in order to alert them.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.449-450
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• 2015

본 논문에서는 실내 소음 측정하고 가시화하여 이 소음이 어느 곳에서 나오는 소음인지 와 심할 경우 유지보수를 할 수 있는 시스템을 제안하였다. 이 논문에서 설명할 내용을 요악하면 기존의 등록되어 있는 지도를 불러와 소음을 측정한다. 소음 측정은 스마트 폰의 마이크를 이용하여 측정한다. 기존에도 스마트폰으로 측정할 수 있는 소음 측정 어플이 있지만 소음을 측정 후 사용자에게 소음을 시각화로 보여주는 것은 없다. 그래서 실내에 비콘을 설치하여 지도내에 위치를 표시하게끔 한다. 실내에서는 좌표가 잘 잡히지 않기 때문에 gps를 사용하는 것보다 비콘을 이용하여 삼각측량법으로 좌표를 잡는다. 비콘은 공간좌표를 DataBase에 저장한다. 저장된 공간좌표를 어플 내에 등록된 지도에 표시해주고 스마트폰을 통한 어플로 측정한 소음을 지도에 찍힌 공간 좌표에 점으로 연결하여 선형보관볍을 이용하여 소리를 맵핑화 시켜 사용자가 눈으로 직접 어느 곳이 소음이 심한지 확인할 수 있다. 추후 개선할 사항으로 지도를 미리 등록하지 않고 측정을 시작하는 동시에 움직이는 거리에 따라 지도가 그려지면서 측정하는 방식을 계획중이다.