• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 한국GIS학회 2008년도 공동춘계학술대회
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• pp.41-44
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• 2008

본 논문은 GPS 수신기와 CDMA 통신모듈을 장착한 이동단말기를 대상으로 자신의 위치를 Windows Mobile 운영체제의 API를 통해 중앙의 서버에게 전송하는 프레임워크를 설계하고 구현한다. 단말기 소프트웨어는 자원의 효율적인 사용과 확장성을 위하여 GPS 쓰레드, 통신 쓰레드 등으로 구성되어 미동기적으로 GPS 위치 정보를 공유 자료구조에 저장하고 응용에서 정의한 주기에 의해 중앙서버에게 보고한다. 서버는 이를 받아 위치로그의 생성, 이동객체 위치 트래킹을 위한 가시화 등 다양한 응용을 작성할 수 있게 된다. Garmin 포맷의 분석, RAS에 기반한 CDMA 통신, 쓰레드 처리, 서버의 로그 생성 등 핵심적인 요소들의 구현에 의해 차량 텔레매틱스 등 다양한 위치기반 응용을 작성할 수 있도록 한다.

• Journal of Institute of Control, Robotics and Systems
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• 제12권9호
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• pp.883-890
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• 2006

Nowadays, CPS is used widely, especially in cases which need more precise position information, such as car navigation systems and even in the mobile robot for position measuring in the outdoor environment. RTK (Real-Time Kinematics) and DGPS (Differential Global Positioning System) have more precise accuracy than the general-purposed GPS. However can't easily use them because of high prices and large size of equipments. In order fur the mobile robot to obtain precise position information it is important that CPS receiver has portability and low price. In this study, we introduce a new GPS data acquisition system that offers the precise position data using the DGPS mechanism and satisfying low cost and portability. In addition to this, we propose an improved data compensation algorithm that offers more accurate position information to the outdoor mobile robot by compensating the error rate of CPS data measured from the three points with geometrical rotation and distance formula. Proposed method is verified by comparing with the precise real position data obtained by RTK. Proposed method has more than 70% performance enhancement.

• Journal of Information Technology Applications and Management
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• 제14권3호
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• pp.169-178
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• 2007

The next generation mobile multimedia network is expected to provide higher-rate multimedia communication services to versatile mobile terminals moving in even higher speed. For achieving more efficient reusability of scarce radio resources and thereby accommodating more user population in this network, the smaller cell such as micro or pico cell structure is used. More efficient and faster hand-over schemes are necessary to prevent the degradation of QoS of multimedia services caused by hand-over processing delay and packet loss during frequent hand-over. This paper proposes a faster and more effective hand-over scheme for high-rate multimedia services in the future mobile multimedia networks. by utilizing the GPS information on the position of the mobile terminal and its estimated moving directions. The simulation results show that our proposed method provides a better performance than the conventional method.

• The Journal of the Convergence on Culture Technology
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• 제1권1호
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• pp.79-85
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• 2015

According to the growing use of the personal GPS in the mobile device recently, the LBS (Local bases service), which processes and refines the GPS information, such as a position-tracking service, a public safety service, a local based information service, has increased steadily. Due to the refraction or reflection of GPS, however, it is impossible to use GPS around or in buildings. Therefore, it is necessary to correct the errors of GPS. We propose the method which corrects the errors of GPS and creates the refined trajectory using intersection region indexing. After analyzing the trajectory, receiving trajectories from many people and identifying the similarity between of trajectories, we will recommend the favorite route and useful information such as restaurant, convenience store, bus station and emergency call service.

• The KIPS Transactions:PartB
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• 제14B권3호
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• pp.163-170
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• 2007

In autonomous navigation of a mobile vehicle or a mobile robot, localization calculated from recognizing its environment is most important factor. Generally, we can determine position and pose of a camera equipped mobile vehicle or mobile robot using INS and GPS but, in this case, we must use enough known ground landmark for accurate localization. hi contrast with homography method to calculate position and pose of a camera by only using the relation of two dimensional feature point between two frames, in this paper, we propose a method to calculate the position and the pose of a camera using relation between the location to predict through perspective transform of 3D feature points obtained by overlaying 3D model with previous frame using GPS and INS input and the location of corresponding feature point calculated using KLT tracking method in current frame. For the purpose of the performance evaluation, we use wireless-controlled vehicle mounted CCD camera, GPS and INS, and performed the test to calculate the location and the rotation angle of the camera with the video sequence stream obtained at 15Hz frame rate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제15권4호
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• pp.327-334
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• 2004

In this paper, a triplexer for Advanced Mobile Phone Service(AMPS), United States-Personal Communication Services(US-PCS), and Global Positioning System(CPS) is designed using L and C lumped elements. The triplexer shows the insertion loss of 0.6 ㏈, 1.1 ㏈, and 1.6 ㏈ for AMPS, US-PCS, and GPS bands, respectively. Also, it shows the attenuation characteristic of less than 18 ㏈, and the VSWR of less than 2.0 through the all pass-band.

• KIPS Transactions on Computer and Communication Systems
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• 제2권12호
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• pp.525-532
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• 2013

Recently smartphones, tablet, etc. Various types of smart terminal is due to the increased security in mobile devices are becoming an issue. How to enter the password in this environment is a very important issue. Difficult to have a secure password input device on various types of mobile devices. In addition you enter on the touch screen the password of character, uncomfortable and it is vulnerable to SSA attack. Therefore, in this paper provide for defense the SSA(Shoulder Surfing Attacks) and useful password input mechanism is proposed with Smartphone GPS uses a value generated via a graphical password techniques.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제14권12호
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• pp.6196-6203
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• 2013

This study examined cadastral surveying technology regulated under the "Special Law for the cadastral surveying", and analyzed the related surveying methods currently used. Based on the analysis, this study suggested the efficient application plan future cadastral surveying projects. The new technologies analyzed were GNSS, GPS RTK, Network RTK, GPS Augmentation System, and the mobile and auto sighting TS. As a result of the analysis, this study suggests that if a receiving technology is possible for the integrated receiving of GPS/GLONASS/Galileo systems, both the accuracy of location determination could be enhanced and stable data could be obtained. The Network RTK technology may solve the constraint receiving factors of satellite information in the long term if a GPS Augmentation System is used. Finally, mobile and auto sighting TS technologies can reduce the personnel factors, but can be applied after the offset problem is overcome.

• International Journal of Contents
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• 제9권1호
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• pp.18-25
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• 2013

Recently, augmented reality has been proved immensely useful on a day to day basis when tied with location-based technology. In this paper, we present a new method for displaying augmented reality contents on mobile devices. We add 3D models on the view of the camera and use location-based services, motion sensors to calculate the transformation of models. Instead of remaining at a fixed position on camera view while moving around a 3D model, the model rotates on display in the opposite direction that the user is walking. We also design client as a ubiquitous client to reduce constraints on disk space and memory capacity on mobile devices. Implementation results show effective use in creating GPS-based 3D view augmented reality contents for Smart Mobile Devices.

• The Journal of Korea Robotics Society
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• 제2권3호
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• pp.221-226
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• 2007

A robust position-sensing system is proposed in this paper for ubiquitous mobile robots which move indoor as well as outdoor. The Differential GPS (DGPS) which has position estimation error of less than 5 m is a general solution when the mobile robots are moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is selected as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position-sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified through the real experiments using a mobile robot prepared for this research and demonstrated.