• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.99-104
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• 2012

The United States will proceed with the effort to modernize the GPS system, and one of its main content is to provide L5 signal. L5 will be transmitted in a radio band reserved exclusively for aviation safety services. And, L5, in combination with L1, will improve the position accuracy via ionospheric correction and robustness via signal redundancy. However, The acquisition processing time of L5 takes longer than that of L1 as the code length of L5 is 10 times longer than that of L1. To reduce this acquisition processing time, a higher number of correlators in the aquisition module should be used. However, there is a problem that this causes increase in the complexity of the correlator configuration and the computation power. So, in this paper, we propose L5 signal tracking scheme using tracking results in the GPS L1/L5 receiver. The proposed scheme could reduce the hardware complexity as the GPS L5 signal acquisition module is not needed, and provide fast and stable tracking of L5 signal by aiding L1 tracking results such as PRN, the code phase synchronization, and the Doppler frequency. The feasibility of the proposed scheme is demonstrated through simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1133-1141
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• 2009

In this paper, we present a distributed fault-tolerant topology control protocol that configure a wireless sensor network to achieve k-connectivity and (k+1)-coverage. One fundamental issue in sensor networks is to maintain both sensing coverage and network connectivity in order to support different applications and environments, while some least active nodes are on duty. Topology control algorithms have been proposed to maintain network connectivity while improving energy efficiency and increasing network capacity. However, by reducing the number of links in the network, topology control algorithms actually decrease the degree of routing redundancy. Although the protocols for resolving such a problem while maintaining sensing coverage were proposed, they requires accurate location information to check the coverage, and most of active sensors in the constructed topology maintain 2k-connectivity when they keep k-coverage. We propose the fault-tolerant topology control protocol that is based on the theorem that k-connectivity implies (k+1)-coverage when the sensing range is at two times the transmission range. The proposed distributed algorithm does not need accurate location information, the complexity is O(1). We demonstrate the capability of the proposed protocol to provide guaranteed connectivity and coverage, through both geometric analysis and extensive simulation.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.423-432
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• 2021

In this study, we investigated and the following conclusions are presented by identifying the current status and problems in order to expand the future's value of the community care project introduced and implemented to improve the quality and care for the elderly's life. First, the needs analysis of the elderly receiving services is composed of patient-centered rather than investigator-centered, and in particular, medical management through medical staff visits should be strengthened, and specialized service items according to gender, age, disability type, and personal preference should be strengthened. This will have to be gradually strengthened. Second, by analyzing the satisfaction, redundancy, and effectiveness of service items, we save money, and consider the consumer-oriented service item composition and application of items necessary for new services. Third, through the introduction of an integrated schedule management system, it is necessary to specialize in pre-booking and visit schedule management between the elderly and the direct service organizations that provide services. Fourth, as an effort to solve the financial problem, it is necessary to prepare a rational resource sharing system with health and medical finance, long-term care insurance system, and social welfare financial project. and it may consider that putting the medical personnel who are from local public medical college input. Through these proposals, the community care business will be able to complete and have future value as a universal aged care system.