• Journal of Korea Spatial Information System Society
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• v.8 no.3
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• pp.65-75
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• 2006

Recently, the technologies related with location-based services have been a promising and vigorously researched area in mobile telecommunication industry. LBS have obtained increasingly high attention particularly in domestic area, due to increases in various LBS services supplied by mobile telecommunication companies. LBS technologies are classified by sub-technology such as location determination technology, LBS platform technology, and LBS application services technology. In this paper, I have examined the trend of LBS technologies by analyzing the issued or published patents from 1991 to 2005. The analyzed results are very useful for avoiding overlapping efforts in developing the LBS related technologies, and searching the direction of development of technologies which are different from previous ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1003-1006
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• 2009

Recently, Ubiquitous computing technology is increasing necessity for object recognition and a location tracking technology to meet various applications. The location tracking technology is the fundamental to the Context-Aware of users in Ubiquitous environment and its efficiency has to be improved using IEEE 802.15.4 ZigBee used in current infra such as ubiquitous sensor network. But because the IEEE 802.15.4 ZigBee protocol has limitation to apply location tracking technology such as ToA and TDoA, Zone-based Location Tracking technology using RSSI is needed. In this paper suggests RSSI-based 802.15.4 ZigBee local positioning protocol to support a positioning tracking service in Ubiqutous environment. And Zone-based location tracking system is designed for actual the indoor location tracking service.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.9-14
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• 2008

In the Reporting Cell Location Management (RCLM) system, a subset of cells in the network is designated as the reporting cells. Each mobile terminal performs location update only when it enters one of these reporting cells. When a call arrives, the paging is confined to the reporting cell the user last reported and the neighboring bounded non-reporting cells. Frequent location update may result in degradation of quality of service due to interference. Miss on the location of a mobile terminal will necessitate a search operation on the network when a call comes in. We must decide the number of reporting cells and which cell should be reporting cell to balance the registration (location update) and search (paging) operations to minimize the cost of RCLM system. This paper proposes a simulated annealing (SA) for optimization of RCLM system.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.836-842
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• 2010

Safety system including location monitoring system for blasting workers was studied. Positioning performance of the location monitoring system was highly dependent on communication protocol and the number of access points in the blasting cell. RTLS(Real Time Location System) is an important technology to develop the location information of workers and variously used to enhance workers safety. Location monitoring system with Cell-ID and RSSI wireless communication technology was verified to have a proper positioning performance for the steel block application.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.571-576
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• 2022

Due to the epochal development of the unmanned technology, the importance of LDT(: Location Detection Technology), which accurately estimates the location of a user or object, is dramatically increased. TOA(: Time of Arrival), which calculates a location by measuring the arrival time of signals, and TDOA(: Time Difference of Arrival) which calculates it by measuring the difference between two arrival times, are representative LDT methods. Based on the signals received from three or more base stations, TOA calculates an intersection point by drawing circles and TDOA calculates it by drawing hyperbolas. In order to improve the radio shadow area problem, a huge number of repeaters have been installed in the urban area, but the signals received through these repeaters may cause the serious error for estimating a location. In this paper, we propose an efficient location estimation technique using the signal received through the repeater. The proposed approach estimates the location of MS(: Mobile Station) employing TOA and TDOA methods, based on signals received from one repeater and two BS(: Base Station)s.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.99-105
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• 2011

Location-Based Service(LBS) is a service that provides a variety of convenience in life using location information that can be obtained by mobile communication network or satellite signal. In order to provide LBS precisely and efficiently, we have to need technologies such as location determination technology, platform technology and server technology first. In this study, we studied on how we can reduce the error on location determination of objects such people and things. Fingerprint location determination method was applied to this study because it can be used at current wireless communication infrastructure and less influenced by a variety of noisy environment than other location determination methods. We used the time of arrival(ToA) method in fingerprint location determination method. In order to confirm the performance of suggested method, we developed location determination test program with LAbVIEW 2010 and performed the test. According to indoor test results, the suggested method reduced the distance error by 24%, 34% and 19% respectively at indoor environment compared with deterministic kWNN and Rice Gaussian fingerprint methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4771-4787
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• 2019

Aimed at the disclosure risk of mobile terminal user's location privacy in location-based services, a location-privacy protection scheme based on similar trajectory substitution is proposed. On the basis of the anonymized identities of users and candidates who request LBS, this scheme adopts trajectory similarity function to select the candidate whose trajectory is the most similar to user's at certain time intervals, then the selected candidate substitutes user to send LBS request, so as to protect user's privacy like identity, query and trajectory. Security analyses prove that this scheme is able to guarantee such security features as anonymity, non-forgeability, resistance to continuous query tracing attack and wiretapping attack. And the results of simulation experiment demonstrate that this scheme remarkably improve the optimal candidate' trajectory similarity and selection efficiency.

• International Journal of Control, Automation, and Systems
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• v.6 no.6
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• pp.828-835
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• 2008

We present a novel method for eye location by means of a two-level classifier scheme. Locating the eye by machine-inspection of an image or video is an important problem for Computer Vision and is of particular value to applications in biomedical imaging. Our method aims to overcome the significant challenge of an eye-location that is able to maintain high accuracy by disregarding highly variable changes in the environment. A first level of computational analysis processes this image context. This is followed by object detection by means of a two-class discrimination classifier(second algorithmic level).We have tested our eye location system using FERET and BioID database. We compare the performance of two-level classifier with that of non-level classifier, and found it's better performance.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.73-74
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• 2007

For a safe operation of HVDC systems, the fault location and clearance of faults in the HVDC lines are important. Past methods for fault location on HVDC cable depend on existence of assistance cables and fault resistance, broken cable and environment of fault location. For complement these problems, in this paper, fault location method using traveling wave and cross correlation function is proposed for HVDC cables. Voltage controlled source and current controlled source HVDC were modeled by EMTDC/PSCAD. The proposed algorithm were verified varying with fault distance, fault resistance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.397-401
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• 2006

In this paper, we proposed a high precision location estimation algorithm using an enhanced decision scheme for RTLS and analyzed its performance in point of an average estimation error distance at 2D coordinates searching area, $300m\times300m$ and LOS propagation environments. Also the performance was compared with that of conventional TDOA algorithm according to the number of available reader and received sub-blink. From the results, we confirmed that the proposed location estimation algorithm using an enhanced decision scheme was able to improve an estimation accuracy even in boundary region of searching area. Moreover, effectively reduced an error distance in entire searching area so that increased the stability of location estimation in RTLS. Therefore, we verified that the proposed algorithm provided a more higher estimation accuracy and stability than conventional TDOA.