• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.575-578
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• 2005

위치기반 서비스 시스템은 유비쿼터스 환경으로의 변화와 함께 여러 응용모델과의 접목으로 가치창출에 대한 가능성이 높은 분야이다. 기존의 버스교통시스템은 Active Badge System 또는 GPS 수신정보를 이용한 일방적 push 형태로 현재위치에 대한 정보만을 사용자에게 알려주었으며 그 정보를 접할 수 있는 특정한 장소가 아니면 정보를 획득할 수 없는 시스템이다. 이 논문에서 제안하는 지능형 버스교통정보 시스템은 근거리 무선 통신이 가능하며 측위시스템을 활용할 수 있는 단말기와, 버스교통의 정보를 담고 있는 ITS(Intelligent Transport System)의 권역교통정보센터서브시스템(RTICS)에 호스트를 이동하면서 사용자 대신 업무를 수행하는 객체인 이동 에이전트를 적용한 시스템으로서, ITS API 표준을 요구하지 않으며 단말기를 소지한 사용자가 어느 곳에서든 능동적으로 버스교통에 대한 다양한 정보를 획득 할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1528-1533
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• 2020

Recently, indoor location recognition technology using Wi-Fi fingerprints has been applied and operated in various industrial fields and public services. Along with the interest in machine learning technology, location recognition technology based on machine learning using wireless signal data around a terminal is rapidly developing. At this time, in the process of collecting radio signal data required for machine learning, the accuracy of location recognition is lowered due to distorted or unsuitable data for learning. In addition, when location recognition is performed based on data collected at a specific location, a problem occurs in location recognition at surrounding locations that are not included in the learning. In this paper, we propose a learning data preprocessing technique to obtain an improved position recognition result through the preprocessing of the collected learning data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.84-93
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• 2011

In order to provide the real time and proper information to the pedestrian who is using the transport connection and transfer center through data collecting and processing process, the design of the test-bed (Gimpo airport)'s communication construction and the technology of the pedestrian location tracking has been researched. The design of the communication construction should make sure that it can provide believable data to the user of the transfer center. At the same time, the location tracking should also be considered, so that the require of the communication efficiency and the location tracking efficiency can be met together. In order to make the efficient location tracking technology, the problems related to the commercial technology based real time location identification will be resolved and the new approach method was proposed and be applied and analysed to the test-bed. The wireless access points can be located in the most real-world situation which has added the characteristics of the real building to the electronic map, and through the analysis of theirs location, they can be set as the mainly necessary points for the communication construction design and the location tracking and the method to locate that points has been proposed. How to set, how to apply it to the test-bed and the examination result will be introduced in this paper.

• The Journal of Society for e-Business Studies
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• v.13 no.4
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• pp.1-16
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• 2008

LBS (Location Based Service) cannot be realized unless we can obtain the user's current location. Therefore, in order to realize indoor LBS, many researchers have been working on WLAN (Wireless Local Area Network) based indoor positioning and tracking. Meanwhile, Kalman filter has been widely used in the field of GPS based outdoor user tracking. The main purpose of this paper is proposing an extended Kalman filter method for indoor tracking. Our experimental results show that Kalman filter can be used to improve the accuracy of the measured tracks and the track can be further improved by making use of the map information.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.46-48
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• 2004

최근의 위치 측위 기술과 무선 통신 기술의 발전에 따라 위치 기반 서비스에 대한 관심이 크게 증가하고 있다. 기존 연구의 단일 노드 기반 시스템으로는 휴대폰 사용자와 같은 대용량의 객체를 처리하는데 어려움이 있다. 본 논문에서는 대용량 이동 객체의 시공간 정보를 관리하기 위해 클러스터 기반 분산 컴퓨팅 구조로 제안된 GALIS(Gracefully Aging Location Information System)의 아키텍쳐 중 객체의 현재 위치 정보를 관리하는 SLDS(Short-term Location Data Subsystem)의 프로토 타입을 개발하였다. 본 논문에서 구현한 시스템은 메인 메모리 데이터 베이스를 사용하여 디스크 접근 시간이 없고 현재 정보와 과거 정보를 분리하여 빠른 검색이 가능하기 때문에 대용량 이동 객체를 관리하며 빠른 응답을 필요로 하는 상황에 효과적으로 대응할 수 있는 이점이 있다.

• Spatial Information Research
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• v.18 no.5
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• pp.1-11
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• 2010

Since January 2009, Seoul Metro Government(SMG) is operating own Network RTK Systems connecting four(4) GNSS Reference Stations which are installed inside Seoul Metro City area. SMG is currently providing VRS data service via wireless internet for Network-RTK and RINEX data observed from GNSS Reference Stations. This paper will discuss utilization of data available from SMG Network-RTK System for various applications, and present the test results on practicalities of Virtual RINEX data. For the utilization of data available from SMG Network- RTK system, 1)NTRIP data delivery of GNSS realtime observables streaming and converting to RINEX at receiving side, 2) monitoring deformation of bulky structures using GNSS observation were discussed. In addition to those discussion, 3) broadcasting VRS correction data for job site via radio modem after acquiring such correction data on-line using NTRIP based GNSS Internet Radio from SMG Network-RTK System were introduced. For the test results on practicalities of Virtual RINEX data, 1) the post-processing results of the GNSS observation data on a certain point with GNSS Reference Station data have been compared to the post-processing results of Virtual RINEX data on the same point generated from SMG Network-RTK System, and 2) VRS RTK positioning results for a certain point and post-processing results of Virtual RINEX data for the point were compared. The results showed only a few mm difference, and the high possibility for using Virtual RINEX data for post-processing applications.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.372-374
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• 2013

스마트 단말에 장착된 센서들로부터 단말의 상황 정보를 수집하고 분석하여, 상황에 적절한 동영상을 단말에게 스트리밍해 주는 서비스 구조를 제안한다. 스마트 단말은 NFC 또는 QR 코드 기반으로 전시물이나 특정 사물에 기등록된 동영상 정보를 획득하고, 저밀도 기반 WiFi 무선 실내 측위 기술을 사용하여 단말이 위치한 실내 공간 정보를 서버에 제공한다. 상황인지형 스트리밍 서버는 단말이 요청한 정보를 토대로 단말의 해상도에 적절한 동영상을 스트리밍 한다. 설계된 상황인지형 비디오 스트리밍 서비스 구조는 전시와 컨벤션, 대형 기관 및 테마파크의 안내 및 홍보 등의 용도로 활용될 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.73-75
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• 2018

LoRaWan(Long Range Wide Area Network)은 저전력, 장거리 특성을 가진 무선 통신기술로 그 특성상 스마트 시티(Smart City), IoT(Internet of Things) 등에 각광받고 있다. 또한 LoRaWan은 Chirp 신호 특성에 의해 실외 삼각측량에 따른 사용자 위치 추정 기술을 제공한다. 본 논문에서는 이러한 LoRaWan의 특성에 더해 Wi-Fi 지문 정보를 활용하여 위치 추정 정확도를 개선하고 또한 이웃 Wi-Fi 단말들, 가령 스마트폰 등의 위치 정보를 LoraWan 게이트웨이와 통신하여 최종적으로 서버에서 측위 할 수 있는 시스템을 제안한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.89-94
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• 2018

This paper investigated the design method of the smart sensor for implementing IoT (Internet of Things) service. The power supply of sensor consistently acquisting data is based on the energy harvesting technology and designed with piezoelectric transducer not affected by surrounding circumstances. The wireless communication interface for the transmission of data is designed with BLE (Bluetooth Low Energy). BLE is highly adequate wireless communication technology for low power consumption and short distance wireless communication. The main application of BLE is beacon whose usage range is extended from O2O (Online to Offline) service, navigator based on indoor positioning technology, and anti-theft/lost child prevention service to mobile game. This paper studied the method to extend wireless coverage for complementing the short wireless transmission distance of BLE. The wireless sensor network based on CATV network is proposed for the easy construction of BLE sensor network and extended wireless coverage.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.