• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1823-1824
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• 2007

핸드폰, PDA, Laptop이 보편화 되면서 이를 이용한 위치 인식 기술의 중요성이 높아지고 있다. 이러한 위치기반 서비스(LBS : Location Based Service)는 GPS를 이용한 실외 서비스와 WLAN, Zigbee, UWB 등을 이용한 실내 서비스로 나눌 수 있다. 본 논문에서는 이미 많은 수의 기반시설(AP : Access Point)가 구축되어 있는 무선랜 기반의 효과적인 위치 측정 기법에 관한 연구를 모색 해보고자 한다. 각 AP에서 받은 신호세기(SS : Signal Strength)를 데이터 베이스에 저장한 후, 이동단말기(MU : Mobile Unit)의 위치가 요구되는 장소에서 다시 신호세기를 측정하여 데이터 베이스와 비교하여 가장 적합한 위치 데이터 정보를 리턴하는 핑거프린트(Fingerprint) 방식을 소개한다. 그리고 불안정한 신호 세기 데이터를 판별하기 위하여 단일 클래스 SVM 기법인 SVDD(Support Vector Data Description)을 이용하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.706-709
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• 2011

모바일 네트워크 고도화 및 네트워크와 단말기의 비약적인 발전으로 모바일 기기의 보급이 확산되고, 시장의 경쟁 본격화에 따른 개방형 플랫폼 증가와 애플리케이션 및 모바일 웹의 활성화가 이뤄지고 있다. 또한 모바일 환경에서의 개발이 표준화 되어가면서 제작 및 배포가 용이해지고 있다. 이러한 환경적인 영향으로 모바일 웹 및 어플리케이션에 대한 보안 위협은 더욱 가중되고 있으며 공격의 규모 및 피해가 증가될 것으로 예상된다. 본 논문에서는 이러한 모바일 환경에서 인증 보안을 강화하기 위해 인증 서비스에 위치정보를 활용하는 방안을 제안하고 개인별로 특화된 인증에 관련된 LBS(Location-Based Service)를 제공할 수 있는 시스템을 구현한다. 이 시스템의 구현을 통해 사용자 위치에 따라 인증 유효성 여부를 체크함으로써 현재의 인증시스템에서 신뢰성과 유효성을 추가적으로 확보 할 수 있음을 증명하고 구체적인 활용 방안을 제안한다.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.1-16
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• 2007

Recently the computing environment has been moved to open architectures that include Web technologies. Web Service is one of import component of the new paradigm. This paper presents a design and implementation of GIS Web Service for mobile devices. As many mobile devices are equipped with GPS (Global Positioning System), it is required to handle the position information more effectively. We have extended the proxy program in the client device to actively send the context information to the server. Based on the context information the server determines the optimal service mode to a particular client. A working example of location?based GIS Web Service is also presented. By using Web Service standards and XML messages we can achieve the maximal interoperability for heterogeneous mobile devices.

• Journal of Korea Spatial Information System Society
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• v.6 no.1 s.11
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• pp.31-50
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• 2004

With the growth of wireless communication networks and mobile devices taking in GPS, Location-Based Service(LBS) is becoming an integral part of mobile applications. LBS can deal with location-aware features such as persons holding mobile phones or vehicles equipped with GPS, and provide the users with the location information of the features. Thus it is necessary to develop moving object database systems to store, manage, and query moving objects which change their locations continuously as time passes. In this paper, we design and implement a query processing component which deals with moving objects as a key data type. For this component, we define a new SQL-like query language(called MOQL) and as a consequence, design and implement modules that analyze and execute queries. It supports various types of operators that process range queries, infer topological relations, compute trajectories, and find k-nearest neighbors. It can be used as a subsystem if other application systems which deal moving objects and also supports ADO.NET interface that can be used to interact end-users.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.299-309
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• 2006

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA becomes increasingly popular. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the Location-based Service (LBS) that exploits the spatial information of moving objects per temporal changes. In order to support LBS efficiently, it is necessary to be able to index and query well a large amount of spatio-temporal information of moving objects. Therefore, in this paper, we investigate how such location information of moving objects can be efficiently stored and indexed. In particular, we propose a novel location encoding method based on hierarchical administrative district information. Our proposal is different from conventional approaches where moving objects are often expressed as geometric points in two dimensional space, (x,y). Instead, in ours, moving objects are encoded as one dimensional points by both administrative district as well as road information. Our method is especially useful for monitoring traffic situation or tracing location of moving objects through approximate spatial queries.

• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.707-718
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• 2007

Recently, much studies for providing mobile users with suitable and useful content services, LBS(Location Based Service) corresponding to the change of users' location, are actively going on. First and foremost, this is basically owing to the progress of location management technologies such as GPS, mobile communication technology and the spread of personal devices like PDA and the cellular phones. Besides, the research scope of LBS has been changed from vehicle tracking and navigation services to intelligent and personalized services considering the changing information of conditions or environment where the users' are located. For example, it inputs the information such as heavy traffic, pollution, and accidents. The query languages which effectively search the stored vehicle and environment information have been studied depending on the increase of the information utilization. However, most of existing moving object query languages are not enough to provide a recommendation service for a user, because they can not be tested and evaluated in real world and did not consider changed environment information. In order to retrieve not only a vehicle location and environment condition but also use them, we suggest a moving object query language for recommendation service and implement a moving object query process system for supporting a query language. It can process a nearest neighbor query for recommendation service which considers various attributes such as a vehicle's location and direction, environment information. It can be applied to location based service application which utilizes the recommended factors based on environmental conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1960-1972
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• 2006

In this thesis, GPS and the electronic mapping were used to realize such a system by recognizing license plate numbers and identifying the location of objects that move at synchronous times with simulated movement in the electronic map. As well, throughout the study, a camera attached to a PDA, one of the mobile devices, automatically recognized and confirmed acquired license plate numbers from the front and back of each cu. Using this mobile technique in a wireless network searches for specific plate numbers and information about the location of the car is transmitted to a remote sewer. The use of such a GPS-based system allows for the measurement of topography and the effective acquisition of a car's location. The information is then transmitted to a central controlling center and stored as text to be reproduced later in the form of diagrams. Getting positional information through GPS and using image-processing with a PDA makes it possible to estimate the correct information of a car's location and to transmit the specific information of the car to a control center simultaneously, so that the center will get information such as type of the cu, possibility of the defects that a car might have, and possibly to offer help with those functions. Such information can establish a mobile system that can recognize and accurately trace the location of cars.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.595-605
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• 2006

In this thesis, GPS and the electronic mapping were used to realize such a system by recognizing license plate numbers and identifying the location of objects that move at synchronous times with simulated movement in the electronic map. As well, throughout the study, a camera attached to a PDA, one of the mobile devices, automatically recognized and confirmed acquired license plate numbers from the front and back of each car. Using this mobile technique in a wireless network, searches for specific plate numbers and information about the location of the car is transmitted to a remote server. The use of such a GPS-based system allows for the measurement of topography and the effective acquisition of a car's location. The information is then transmitted to a central controlling center and stored as text to be reproduced later in the form of diagrams. Getting positional information through GPS and using image-processing with a PDA makes it possible to estimate the correct information of a car's location and to transmit the specific information of the car to a control center simultaneously, so that the center will get information such as type of the car, possibility of the defects that a car might have, and possibly to offer help with those functions. Such information can establish a mobile system that can recognize and accurately trace the location of cars.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.35-42
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• 2010

Geo-location using a cellular network is a core technology for LBS together with GPS. With preamble symbols broadcasted in each frame, geo-location using WiBro network can be easily implemented. Because the WiBro network has a cellular structure, it is difficult for a mobile station to detect signals from multiple base stations. In order to get user position using trilateration, long integration techniques for sensitivity enhancement should be employed. This paper presents hybrid integration scheme for WiBro network. By analyzing coherent and non-coherent integration loss according to frequency residual and SNR respectively, optimal combination of the hybrid integration is proposed. Simulation results show that the hybrid integration method is profitable in WiBro network when the frequency residual is estimated and compensated accurately.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.421-426
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• 2016

Fluid is normally used so that certain drug can be administered to patients for certain period of time. There are many incidents in which patients or guardians need to call upon medical staff after estimating the time of fluid injection termination. In case fluid injection is terminated during certain period such as sleeping time or others, it may cause more fatigue for either patients or guardians. Also, it may lead to ineffective work as medical staff needs to monitor the quantity of fluid several times in order to check the time of fluid injection termination. Therefore, the purpose of this study is to propose LBS system combined of minimum equipment and active RFID to monitor the level of fluid in order to solve abovementioned problems. Also, it is expected to enhance the quality of medical service with service in which real-time monitoring of fluid quantity and patient location is conducted to provide accurate information to either patients, guardians, or medical staff(nurse) so that medical staff can locate and see patients at the time of fluid injection termination.