• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1779-1788
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• 2012

Recently, demands of application services in consideration of interior environment according to the stream of times, Ubiquitous. In case of interior location-based service, WLAN is now mostly used. But it is largely affected by environmental changes. To solve this problem, lots of studies on UWB are underway. The reason why studies on UWB are much made lies in that it is not much affected by environment changes owing to radio wave characteristics. So this study suggests the location correction algorithm which derives values with less influence of environment and high accuracy and corrects with more accurate location information using Ubisense system based on UWB technologies. The location correction algorithm suggested is one made after constructing environment database and use it to estimate more accurate location from the location measuring system in a high position.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.1-7
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• 2012

This paper proposes a new indoor location recognition system using a ZigBee network and a global positioning system(GPS). The proposed location recognition system applies GPS values that are mainly used for outdoor location recognition, to indoor location recognition; hence the techniques conventionally separated for the indoor and outdoor location recognition are integrated into one location recognition technique. The proposed system recognizes a location using the distance between nodes. Although the distance between nodes can be calculated by measuring the strength of the received ZigBee signals, generally the measured distance is not accurate and has high error rates since the strength of the ZigBee signals is different depending on the distance. In order to reduce the error rate, we have subdivided the output power of the received ZigBee signals into five levels. When a moving node generates a signal, each fixed node transmits the received signal strength and its own GPS information to other nodes, so the moving node can find its own accurate location in terms of the received signals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.954-960
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• 2009

In this paper, Indoor Positioning System based on Wi-Fi system which is one of the key technology in LBS(Location Based Service) is proposed. The proposed system estimates distance between MS(Mobile Station) and AP(Access Point) using RSSI(Received Signal Strength Indicator). RSSI is affected by outlier that originate from indoor environment complexity and obstacle. In this paper, we introduce a Robust outlier Extended Kalman Filter that can ignore, real-time outlier in the observations. To demonstrate performance of proposed indoor positioning system, we used a PDA as the MS.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.63-71
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• 2012

This paper presents a design and implementation of U-Seum(Ubiquitous Museum) system based on the LBS(Location Based Service) and mobile augmented reality technique. The mobile services under the smart space of the ubiquitous environments have been expanded in the various fields. In this study, we introduce U-Seum which supports tourists in the museum. U-Seum is developed by use of the position tracking technique based on Wi-Fi and mobile augmented reality. The GPS which is widely used in the position tracking has a difficulty to be utilized in the inside of the building because it requires the Line-of-Sight between a sender and a receiver. Therefore, in this paper, we develop a realtime tour-supported service through experience and evaluate the performance of the system in the world famous UNESCO's Hwa-Seong Museum by measuring the distance from the Wi-Fi signal which is suitable to track the position interior of the museum. U-Seum provides various push services such as mobile augmented reality service for explanation of the artifacts of the museum, game services and the statistics information of the tourist when the tourist approach a specific AP. U-Seum is developed in the Haw-Seong Museum by the support of the Swon Haw-Seong Cultural Foundation. With a field test, we prove that the excellence and expandability of the system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8C
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• pp.731-740
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• 2012

To offer indoor location-aware services, the needs for efficient and accurate indoor localization system has been increased. In order to meet these requirement, we presented the BLIDx(Bidirectional Location ID exchange) protocol that is efficient localization system based on sensor network. The BLIDx protocol can cope with numerous mobile nodes simultaneously but the precision of the localization is too coarse because that uses cell based localization method. In this paper, in order to compensate for these disadvantage, we propose the fingerprint overlapping method by modifying a fingerprinting methods in WLAN, and localization system using proposed method was designed and implemented. Our experiments show that the proposed method is more accurate and robust to noise than fingerprinting method in WLAN. In this way, it was improved that low location precision of BLIDx protocol.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1126-1133
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• 2013

For providing personalized intelligent services to users, 3 dimensional indoor positioning technology to recognize the position of person and equipment becomes important. In this paper, the acoustic signal generated from the proliferated smart phone is received from the 5 microphones equipped in the front panel of 3D positioning system, and the two proposed methods estimate the 3D coordinate of the smart phone, and finally it is verified using the implemented experimental system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.151-163
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• 2014

The recent wearable device's applications concentrates on providing diverse services such as location based service, context aware service to the users. These various services are implemented by the interactions between the wearable device and the user. In the legacy system, the interaction requires certain explicit configuration from the user. If the user is unfamiliar with the IT technology, it will be impossible to get the wanted service. Therefore, a new autonomous communication concept among neighbor devices is essential for people who is unfamiliar with the IT technology. The implicit human computer interface enables the user to acquire the services, even though the user don't know the IT technology. In this paper, we propose two BLE based protocols (B-LIDx protocol, B-PniP). B-LIDx protocol is the protocol for locationing the mobile device in indoor. B-PniP is a zero-configure opportunistic direct M2M communication protocol between neighbor devices to achieve the autonomous communication concept with zero-configuration. The protocol's evaluations are performed by measuring the time for finding the location of a mobile device in actual environment and aligning the time spent in services using the B-PniP.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.97-104
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• 2008

Recently, interests on positioning system for location-based services have been significantly increased. Many indoor environment systems using fingerprint scheme have been designed to take more accuracy of positioning, but they are inefficient in adapting to change of environments. In this paper, we focus on a client-based positioning system over WLAN for decreasing installation cost and adapting to change of environments. In the proposed system, APs with stable RSSI are selected as base APs independently for each reference point. Experimental results show that proposed system expands service area approximately 20% much than traditional systems using K-NN algorithm and needs only 20% modification process to fingerprint data compare with traditional systems whenever environment conditions are changed.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10a
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• pp.146-147
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• 2007