• Spatial Information Research
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• v.23 no.2
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• pp.59-68
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• 2015

According to the NGIS (National Geographic Information System) project conducted since 1995, the central and local government has been accumulating huge amount of geospatial data. Korean Ministry of Land, Infrastructure and Transport started its GeoSpatial open platform (V-World) service in January 2012, also offering a wide range of functions and services. However, the National GeoSpatial open platform is still woefully deficient for the users to find their desired data, lack of data for private business area, insufficient in publicity of local government and public-private partnerships. Through analyzing current research trend after GeoSpatial open platform served for three years, study on overseas expansion, system links, service improvement, utilization and future strategy has been mainly conducted. This study, by analyzing the advanced overseas GeoSpatial platform as well as domestic research trend and combining the concept of new technology, business platform and SMG (Seoul Metropolitan Government)'s GeoSpatial platform, proposes a policy for the construction of future GeoSpatial Open Platform model.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.728-732
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• 2008

GeoRSS is RSS which contains geospatial information, and it supports to supply diverse kinds of data through mash-up map service like the google map. It helps to implement efficient web service with simple java-scripts, but sometimes initial page loading takes too much time and causes heavy traffic when it includes lots of multimedia data. In this paper, we propose a splitting method of GeoRSS for fast accessing. As the result of experiments, we achieved improvement of browsing speed and reducing of initial data traffic.

• Journal of The Geomorphological Association of Korea
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• v.28 no.2
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• pp.31-44
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• 2021

Due to recent climate change, continuous soil loss is occurring in the mountainous watershed. The development of geographic information systems allows the spatial simulation of soil loss through hydrological models, but more researches applied to the mountain watershed areas in Korea are needed. In this study, prior to simulating the soil loss characteristics of the mountainous watershed, the field monitoring and the SWAT and GeoWEPP models were used to simulate and analyze the rainfall and runoff characteristics in the mountainous watershed area of Jirisan National Park. As a result of monitoring, runoff showed a characteristic of a rapid response as rainfall increased and decreased. In the simulation runoff results of calibrated SWAT models, R², RMSE and NSE was 0.95, 0.03, and 0.95, respectively. The runoff simulation results of the GeoWEPP model were evaluated as 0.89, 0.30, and 0.83 for R², RMSE, and NSE, respectively. These results, therefore, imply that the runoff simulated through SWAT and GeoWEPP models can be used to simulate soil loss. However, the results of the two models differ from the parameters and base flow of actual main channel, and further consideration is required to increase the model's accuracy.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.122-130
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• 2014

GEO-KOMPSAT-2 which is under development by KARI to be launched in 2018 is expected to be injected into its orbit through the standard GTO(Geostationary Transfer Orbit) or SSTO(Supersynchronous Transfer Orbit). While the standard GTO mission has been applied for the most of the geostationary satellites, the SSTO mission is rare case and significantly different from the standard GTO mission in technical point of view. This paper lists the operational constraints to be applied for GEO-KOMPSAT-2 SSTO mission, and introduces a preliminary LAE burn plan for GEO-KOMPSAT-2 mission. In order to evaluate the developed plan, a simulation study has been performed considering ground station visibility.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1236-1251
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• 2013

Sharing geo-tagged photos has been a hot social activity in the daily life because these photos not only contain geo information but also indicate people's hobbies, intention and mobility patterns. However, the present raw geo-tagged photo routes cannot provide information as enough as complete GPS trajectories due to the defects hidden in them. This paper mainly aims at analyzing the large amounts of geo-tagged photos and proposing a novel travel route restoring method. In our approach we first propose an Interest Measure Ratio to rank the hot spots based on density-based spatial clustering arithmetic. Then we apply the Hidden Semi-Markov model and Mean Value method to demonstrate migration discipline in the hot spots and restore the significant region sequence into complete GPS trajectory. At the end of the paper, a novel experiment method is designed to demonstrate that the approach is feasible in restoring route, and there is a good performance.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.3
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• pp.171-190
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• 2008

With growing applications of wireless video streaming, an efficient video traffic model featuring modern high-compression techniques is more desirable than ever, because the wireless channel bandwidths are ever limited and time-varying. We propose a modeling and analysis method for video traffic by a class of stochastic processes, which we call '$GEO^Y/G/{\infty}$ input processes'. We model video traffic by $GEO^Y/G/{\infty}$ input process with gamma-distributed batch sizes Y and Weibull-like autocorrelation function. Using four real-encoded, full-length video traces including action movies, a drama, and an animation, we evaluate our modeling performance against existing model, transformed-M/G/${\infty}$ input process, which is one of most recently proposed video modeling methods in the literature. Our proposed $GEO^Y/G/{\infty}$ model is observed to consistently provide conservative performance predictions, in terms of packet loss ratio, within acceptable error at various traffic loads of interest in practical multimedia streaming systems, while the existing transformed-M/G/${\infty}$ fails. For real-time implementation of our model, we analyze G/D/1/K queueing systems with $GEO^Y/G/{\infty}$ input process to upper estimate the packet loss probabilities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5877-5897
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• 2018

With the popularity of mobile networks and smartphones, geo-textual publish/subscribe messaging has attracted wide attention. Different from the traditional publish/subscribe format, geo-textual data is published and subscribed in the form of dynamic data flow in the mobile network. The difference creates more requirements for efficiency and flexibility. However, most of the existing Top-k geo-textual publish/subscribe schemes have the following deficiencies: (1) All publications have to be scored for each subscription, which is not efficient enough. (2) A user should take time to set a threshold for each subscription, which is not flexible enough. Therefore, we propose an efficient and flexible Top-k geo-textual publish/subscribe scheme. First, our scheme groups publish and subscribe based on text classification. Thus, only a few parts of related publications should be scored for each subscription, which significantly enhances efficiency. Second, our scheme proposes an adaptive publish/subscribe matching algorithm. The algorithm does not require the user to set a threshold. It can adaptively return Top-k results to the user for each subscription, which significantly enhances flexibility. Finally, theoretical analysis and experimental evaluation verify the efficiency and effectiveness of our scheme.

• Journal for History of Mathematics
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• v.25 no.1
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• pp.71-88
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• 2012

The purpose of this study is to find the way to build the concept image about natural logarithm and the method is using definite integral in calculus under GeoGebra environment. When the students approach to natural logarithm, need to use dynamic program about the definite integral in calculus. Visible reasoning process through using dynamic program(GeoGebra) is the most important part that make the concept image to students. Also, for understand mathematical concept to students, using GeoGebra environment in dynamic program is not only useful but helpful method of teaching and studying. In this article, about graph of natural logarithm using the definite integral, to explore process of understand and to find special feature under GeoGebra environment. And it was obtained from a survey of undergraduate students of mathmatics. Also, relate to this process, examine an aspect of students, how understand about connection between natural logarithm and the definite integral, definition of natural logarithm and mathematical link of e. As a result, we found that undergraduate students of mathmatics can understand clearly more about the graph of natural logarithm using the definite integral when using GeoGebra environment. Futhermore, in process of handling the dynamic program that provide opportunity that to observe and analysis about process for problem solving and real concept of mathematics.

• Spatial Information Research
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• v.22 no.6
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• pp.91-103
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• 2014

The high popularity of geo-referenced mash-up improves the quality and availability of geo-referenced contents. Such contents which accurately represent the real world in street level as well as in aerial level have appeared. Despite the advent of geo-referenced contents of street level, it is still hardly used for mash-up. In this study, we thus find out its obstacles to spatial mash-up and solutions to overcome them to activate the mash-up based on street level contents. By analyzing the current geo-referenced content with respect to its spatial scope and the way of representation, we draw the limitations of current street level contents. Furthermore, we propose the 'new media geo-referenced content' as a solution to overcome those limitations. With 'new media geo-referenced content', it is able to determine the 3D coordinates of given object in real world. Using those coordinates, database linkage can be more closer, flexible and organic. Such 'new media geo-referenced content' can contribute to activation of geo-referenced contents in street level and its mash-up.

• Electronics and Telecommunications Trends
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• v.39 no.4
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• pp.1-9
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• 2024

As Advanced Air Mobility (AAM) technologies evolve, ensuring accurate navigation and localization in complex urban airspaces has become crucial. Because the Global Navigation Satellite System (GNSS) is prone to vulnerabilities in urban flight environment, an alternative localization technique is required. This paper examines vision-based localization technologies to enhance GNSS-free navigation. In addition, we explore various geo-referencing studies that utilize pre-existing spatial databases to improve the accuracy of vision-based localization under GNSS-denied conditions. This paper discusses the various types of onboard vision camera sensors, vision-based localization, spatial information databases, feature extraction methods, and matching techniques that contribute to the development of a vision-based localization and geo-referencing system for AAM, ensuring safety and reliability in urban operations.