• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2004년도 International Conference on Digital Policy & Management
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• pp.185-202
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• 2004

Recent development in wireless computing and GPS technology cause the active development in the application system of location information in real-time environment such as transportation vehicle management, air traffic control and location based system. Especially, study about vehicle location tracking system, which monitors the vehicle's position in a control center, is appeared to be a representative application system. However, the current vehicle location tracking system can not provide vehicle position information that is not stored in a database at a specific time to users. We designed a vehicle location tracking system that could track vehicle location using mobile interface such as PDA. The proposed system consist of a vehicle location retrieving server and a mobile interface. It is provide not only the moving vehicle's current location but also the position at a past and future time which is not stored in database for users.

• 한국콘텐츠학회논문지
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• 제8권4호
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• pp.264-272
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• 2008

이포지션(ePosition) 서비스는 유무선 인터넷을 통하여 지구상의 특정 지점의 위치정보를 물리적 주소 대신 그에 대응되는 고유한 위치식별 ID인 논리적인 주소로 제공하는 기술이다. ePosition 서비스를 활용하여 임의의 단말기를 이용하는 사용자에게 유무선 인터넷을 통하여 분산된 다수의 ePosition 서버를 지원하는 유비쿼터스 지리정보 서비스를 제공하기 위해서는 실제로 위치 정보가 저장 관리되는 ePosition 서버의 도메인네임을 레지스트리에 등록 저장함으로써 원하는 위치정보가 저장되는 ePosition 서버 접속이 자동적으로 이루어지도록 하는 것이 바람직하다. 또한 이미 표준으로 정해져 있는 DNS와 연계하여 ePosition 서비스를 효율적으로 제공하기 위해서는, DNS 서비스를 위한 표준규격을 만족하는 범주 내에서 ePosition서버의 도메인네임을 지정하여 등록할 수 있도록 새로운 리소스 레코드 타입을 정의할 필요가 있다. 본 논문은 ePosition 서비스를 위한 DNS 리소스 레코드를 정의하여 ePosition 서비스를 제공하는 시스템을 구현함으로서, 이미 구축되어 있는 DNS 기반의 인터넷과 연동이 원활하게 이루어지고 확장성이 뛰어나며 효율적인 ePosition 기반의 새로운 위치정보제공 서비스 방안을 제안한다.

• 한국정보통신학회논문지
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• 제11권3호
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• pp.627-633
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• 2007

이 논문은 선적 및 하역 작업을 위해 겐추리 크레인으로 들어오는 컨테이너 트레일러의 위치 추적 시스템에 대하여 기술한다. 위치 추적 시스템은 트레일러가 겐추리 크레인에 접근하였을 때 트레일러의 정지 지점을 운전자에게 알려준다. 위치 측정 센서는 RF 신호와 초음파 방식을 채택한 크리켓 mote 모듈을 사용하였다. 실시간 전송을 위해 위치 측정 주기를 단축하였으며 삼각측량 방법에 따른 3 차원 위치 계산식과 환경적 요인에 의한 거리 측정 오류 감소 방법을 제시하였다. 측정된 위치는 블루투스 통신을 통해 주기적으로 운전자 앞의 PDA (Personal Digital Assistant)에 전송된다. 실내외 테스트 결과 위치 오류는 3 cm 이내로 개선되었으며 위치 측정 표시 주기는 평균 0.5초였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.340-342
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• 2003

Location based services based on positions of moving objects are expanding the business area gradually. The location is included all estimate position of the future as well as the position of the present and the past. Location based routing service is active business application in which the position information of moving objects is applied efficiently. This service includes the trajectory of past positions, the real-time tracing of present position of special moving objects, and the shortest and optimized paths combined with map information. In this paper, we describes the location based routing services is extend in distributed web GIS environment. Web GIS service systems provide the various GIS services of analyzing and displaying the spatial data with friendly user - interface. That is, we propose the efficient architecture and technologies for servicing the location based routing services in distributed web GIS environment. The position of moving objects is acquired by GPS (Global Positioning System) and converted the coordinate of real world by map matching with geometric information. We suppose the swapping method between main memory and storages to access the quite a number of moving objects. And, the result of location based routing services is wrapped the web-styled data format. We design the schema based on the GML. We design these services as components were developed in object-oriented computing environment, and provide the interoperability, language-independent, easy developing environment as well as re - usability.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.757-766
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• 2007

Location services are used in mobile ad hoc and hybrid networks to locate either the geographic position of a given node in the network or a data item. One of the main usages of position location services is presented in location based routing algorithms. In particular, geographic routing protocols can route messages more efficiently to their destinations based on the destination node's geographic position, which is provided by a location service. In this paper, we propose an adaptive location service on the basis of fuzzy logic called FHLS (Fuzzy Hierarchical Location Service) for mobile ad hoc networks. The adaptive location update scheme using the fuzzy logic on the basis of the mobility and the call preference of mobile nodes is used by the FHLS. The performance of the FHLS is to be evaluated by a simulation, and compared with that of existing HLS scheme.

• 한국연초학회지
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• 제13권1호
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• pp.74-81
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• 1991

This study was conducted to find out physical and chemical characteristics of burley and flue-cured tobacco leaves followed by location, growing season and leaf position during the period 1985 to 1989. The locations of flue-cured tobacco were 7(65farms) and burley tobacco were 4(40 farms). 1. Flue-cured tobacco leaves The locations of Ch'unch'on and Suwon were higher nicotine and ether extract content, Taegu and Chinju were higher total nitrogen content but Chiniju was lower red color of cured leaves than that of other location. Nicotine content increased but total sugar content decreased during the period 1985 to 1989. Nicotine and total nitrogen content increased but crude ash decreased from lower leaf position to higher leaf position. Total sugar and ether extract content were variable followed by leaf position. 2. Burley tobacco leaves. The location of Ch'onju was higher ether extract content than that of others location, but there was no significant difference the others chemical component among location. Nicotine content and red color of cured leaves increased during the period 1985 to 1989. Nicotine, total nitrogen and ether extract content increased but decreased crude ash content and brightness of cured leaf from lower leaf position to higher leaf position.

• Journal of Communications and Networks
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• 제14권4호
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• pp.396-409
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• 2012

With the proliferation of diverse wireless devices, there is an increasing concern about the security of location information which can be spoofed or disrupted by adversaries. This paper investigates the characterization and detection of location spoofing attacks, specifically those which are attempting to falsify (degrade) the position estimate through signal strength based attacks. Since the physical-layer approach identifies and assesses the security risk of position information based solely on using received signal strength (RSS), it is applicable to nearly any practical wireless network. In this paper, we characterize the impact of signal strength and beamforming attacks on range estimates and the resulting position estimate. It is shown that such attacks can be characterized by a scaling factor that biases the individual range estimators either uniformly or selectively. We then identify the more severe types of attacks, and develop an attack detection approach which does not rely on a priori knowledge (either statistical or environmental). The resulting approach, which exploits the dissimilar behavior of two RSS-based estimators when under attack, is shown to be effective at detecting both types of attacks with the detection rate increasing with the severity of the induced location error.

• Journal of Mechanical Science and Technology
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• 제15권10호
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• pp.1369-1379
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• 2001

This paper focuses on a development of a sensor system measuring locations of a vehicle to localize a mobile robot while it tracks on the track (location sensor) . Also it focuses on a system configuration identifying the vehicle's orientation and distance from the object while it is stationary at certain station (position sensor) . As for the location sensor it consists of a set of sensors with a combined guiding and counting sensor, and an address-coded sensor to localize the vehicle while moving on the rail. For the position sensor a PSD (Position Sensitive Device) sensor with photo-switches sensor to measure the offset and orientation of the vehicle at each station is introduced. Both sensor systems are integrated with a microprocessor as a data relay to the main computer controlling the vehicle. The location sensor system is developed and its performance for a mobile robot is verified by experiments. The position measuring system is proposed and is robust to the environmental variation. Moreover, the two kinds of sensor systems guarantee a low cost application and high reliability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.41-42
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• 2006

In this paper, we propose a rapid asynchronous UWB (Ultra Wide Band) position location scheme based on double RTTs (Round-Trip Transmissions). In the proposed scheme, to avoid performance degradation of the position location in harsh multipath channel environments where LoS (Line-of-Sight) components are not always guaranteed, the remaining RTT information is solved from realistic double RTTs. Simulation results in IEEE 802.15.4a UWB channel models reveal that the proposed scheme can achieve closely comparable position location accuracy of the conventional ToA (Time of Arrival) method based on triple RTTs, while reducing the processing delay required for the calculation of the position locations.

• Journal of Communications and Networks
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• 제9권3호
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• pp.254-264
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• 2007

A promising approach to improve the performance of mobile location system is the use of antenna arrays in both transmitter and receiver sides. Using advanced array signal processing techniques, such multiple-input multiple-output (MIMO) communication systems can offer more mobile location information by exploiting the spatial properties of the multipath channel. In this paper, we propose a novel approach to determine the position of mobile terminal based on estimated multipath signal parameters using only one base station in MIMO communication systems. This approach intends to minimize the error occurring from the estimation of multiple paths and gives an optimal estimation of the position of mobile terminal by simultaneously calculating a set of nonlinear location equations. This solution breaks the bottleneck of conventional mobile location systems which have to require multilateration of at least three base stations.