• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.191-198
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• 2022

In order to increase the practical use and navigational application performance of the Korean Positioning System (KPS), it is required to provide interoperability with other Global Navigation Satellite System (GNSS). This kind of interoperability can be obtained by broadcasting the time offset between KPS and GNSS using a KPS navigation message. With the assumption that KPS Time (KPST) will be generated by the similar method and equipment of UTC(KRIS), the overall behavior of KPST will be close to that of UTC(KRIS). Therefore, the time offset between KPST and GPS Time (GPST) is estimated by using UTC(KRIS) instead of KPST because KPST can not available at the present time. In this paper, we describe the estimation results of the KPS to GPS Time Offset (KGTO) obtained by using a GNSS time transfer receiver which reference inputs are fed from UTC(KRIS). The estimated KGTO performance is compared to the time offset between UTC(KRIS) and UTC(USNO) which is used to generate GPST and considered as the real GPST. The time offset between UTC(KRIS) and UTC(USNO) is obtained by using the Bureau International des Poids et Mesures (BIPM) Circular T report. From the results, it is observed that KGTO can be estimated under 10 ns with the assumption that KPST will be generated by a similar method of UTC(KRIS) generation.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.13-22
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• 2012

This study was conducted to establish ecotourism as an introduction to sustainability and international cooperation. As a plan to retain the original meaning of ecotourism, the introduction of a program to certify/designateecotourism is being vitalized in many countries around the world. In Korea as well, an agenda to the introduction of an "Ecotourism Designation System,"which aims to ensure the quality of ecotourism at a certain level, was submitted by the Ministry of Environment to the National Assembly in June 2011, and the promotion for a demonstration program is planned this year to introduce the system. Japan has been carrying out the certification systems Good Eco-tour, which certifies the sustainability of ecotourism providers and accommodations since 2006, respectively, and has been securing the sustainability of ecotourism by enactment in 2008, as the world's first law to promote ecotourism. And the second general conference of the first Global Partnership for Sustainable Tourism(GPST) was held in Korea in March 2012, particularly, there was an agreement that the promotion of Asia and the Pacific Area Network for sustainable tourism would center around Korea, and accordingly, it is expected that Korea's status as a core country for ecotourism in the Asia-Pacific Area will increase. While the demand for an approach to natural resources is rapidly increasing, we should be active in providing an institutional strategy such as a designation system to secure the sustainability of ecotourism and seeking a plan for cooperation and network vitalization in the Asia-Pacific Area where similar natural resources and cultures are shared.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1310-1317
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• 2012

The Global Navigation Satellite System (GNSS) like US Global Positioning System (GPS) and EU Galileo are based on providing precise time and frequency synchronized ranging signals. Because of the exploitation of very precise timing signals these GNSS are used to provide both navigation and time distribution services. Moreover, because the positioning accuracy will improve as more satellites become available, we should expect that a combination of Galileo and GPS will provide better performance than those of both systems separately. However, Galileo will not use the same time reference as GPS and thus, a time difference arises - the GPS-Galileo Time Offset (GGTO). The navigation solution calculated by receivers using signals from both navigation systems will consequently contain a supplementary error if the GGTO is not accounted for. In this paper, we compared GPS Time (GPST) with Galileo Sytem Time (GST) and analyzed the effects of GGTO on positioning accuracy by simulation test. And then we also analyzed the characteristics of two representative GGTO correction methods such as the navigation message based method at system level and the estimation method at user level and propose the conceptual design of the novel correction method being capable of preventing previous method's problems.