• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.375-383
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• 2012

Together with the GPS-based approach, geolocation through mobile communication networks is a key technology for location-based service. Since the Mobile WiMAX system is considered as a candidate for fourth-generation mobile systems, it is important to investigate its location capability. The geolocation of Mobile WiMAX can be realized when the preamble symbols in the down-link channel are appropriately used for a TDOA (Time-Difference-of-Arrival) approach. However, the cellular structure of Mobile WiMAX inevitably generates co-channel interference, and it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. Therefore, for geolocation via multilateration using the Mobile WiMAX network, it is very important to increase hearability. This paper proposes a geolocation method for Mobile WiMAX which employs interference cancellation and preamble signal overlapping for the enhancement of hearability. A novel interference cancellation strategy for complex-valued Mobile WiMAX signals is presented which has an iterative structure. Simulation results show that the proposed geolocation method provides the user's position with an accuracy of less than 20 m through the Mobile WiMAX cellular network if there is no multi-path or NLOS (None-Line-of-Sight).

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.678-683
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• 2006

A novel and intuitive way of accessing applications of mobile devices is presented. The key idea is to use grip-pattern, which is naturally produced when a user tries to use the mobile device, as a clue to determine an application to be launched. To this end, a capacitive touch sensor system is carefully designed and installed underneath the housing of the mobile terminal to capture the image of the user's grip-pattern. The captured data is then recognized by a recognizer with dedicated preprocessing and postprocessing algorithms. The recognition test is performed to validate the feasibility of the proposed user interface system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.49-55
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• 2012

A study on e-book viewer terminal in the native language of the platform-dependent studies are based, This is inefficient in memory usage and screen rendering speed, and there are frequent system updates, e-book viewer, the nature of mobile terminal platform application compatibility issues may occur. In this paper, using the mobile app framework in order to design e-book e-book viewer, analyzed the structure of ePub file parser and file more structured modules were designed and MVC. Designed and implemented to test the functionality of the memory information that is currently running to provide the ability to show the relationship of DDMS and layout components were used to show Hierarchy Viewer. As a result, rendering the screen 150%, 84% in the heap memory usage, improved performance was confirmed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4A
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• pp.385-392
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• 2006

It is widely accepted that high user densities in mobile multimedia environments can only be achieved with micro- and pico-cell. The smaller cell size causes frequent handovers between cells, and decreases permissible handover processing delay. This may result in the handover failure, in addition to the loss of some packets during the handover. In these cases, re-transmission is needed in order to compensate errors, which in turn triggers a rapid degradation of throughput. In this paper, we propose a new handover scheme for the next generation mobile communication systems, in which the handover setup process is done in advance before a handover request by predicting the handover cell based on mobile terminal's current position and moving direction. Simulation is performed in order to analyze the handover failure rate and packet loss rate. Simulation results show that our proposed method provides a better performance than the conventional method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.959-962
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• 2009

Recently, a multi-core system is studied for single terminal's operations on various service networks for mobile systems. Therefore, it is expected that mobile systems capable of supporting WCDMA, GSM, and WiBro would be developed. Mobile systems for supporting various service networks is able to be implemented on a single chipset via SoC(System on Chip) technology, thus a noble modem design proper for SoC technology is necessary. As those systems shall be operated at different frequency band with only a single terminal, a problem that a nonlinear characteristic according to the system and its frequency band is occurred. In this paper a noble modem design for multi-core systems is proposed and the nonlinear characteristics for those systems is analysed. The proposed modem design is based on OFDM(Orthogonal Frequency Division Multiplexing) and MC-CDMA scheme. And nonlinear characteristic analysis is done by PSD measurement.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.21-31
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• 2008

Ubiquitous environment is constructed by development of an IT technology, offer environment of many service changed to mobile environment. Also, existed service offered at fixed position like home or company, but according to development of mobile device. user require service as moving. Wibro can offer as user moving using mobile device. As requirement should be included authentication, in case of authentication between UICC and AAA authentication server is offered in Wibro, service is available. However, when UICC requires initial authentication to AAA authentication server, identification information of UICC expose as plaintext, so privacy infringement of mobile device occurs. Therefore, identification information of terminal generate randomly using OTP(One-Time Password) that generated in mobile terminal, and we proposed mechanism of privacy protection. Also, we proposed mechanism that offer secure service to user as offer authentication from OTP framework, and offer OTP combination authentication detailedly.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.452-457
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• 2005

It is the mobile platform that has held important position in wireless internet contents service using mobile phone terminal so far. There have been a variety of mobile platforms developed by several mobile service providers for their purpose and convenience. In this paper, in addition to the merits and demerits analysis and comparison between each platform, the WIPI is introduced and reviewed as a Korean standard wireless internet platform in terms of technology.

• Journal of Internet Computing and Services
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• v.2 no.3
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• pp.1-8
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• 2001

A school record system by mobile phones is developed using the mobile agent. This developed system support all the wireless protocols by o combined wire and wireless internet Sever for WAP, ME. As a result, it is possible for a student to check his result of achievement and bulletin board by his mobile terminal anywhere, anytime.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.67-72
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• 2014

Zigbee is a wireless communication technology optimized for Wireless Sensor Network environment. Implementation of location estimation system is based on Zigbee. In this paper, we implement mobile information system using zigbee technology. The proposed system is composed of mobile terminal software and mobile reader softwrae. We also used our hardware in previous system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.101-104
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• 2001

Many applications are developed on variety type of mobile terminal with mobile tole-communication improvement. We suggest that we offer more improve multimedia environment on that development. So we design SWF player which supports Macromedia SWF file format. It is application that animation and graphic module are independent of system. In addition to, we implement SWF player on mobile communication environment. for the purpose of it, we adapt AKL concept, which is designed for the consistent interface on heterogeneous operating system environment.