• Journal of KIISE
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• v.42 no.6
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• pp.781-790
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• 2015

In recent times, microblogs have become popular owing to the development of the Internet and mobile environments. Among the various types of microblog data, those containing location data are referred to as spatial social Web objects. General aggregations of such microblog data include data aggregation per user for a single piece of information. This study proposes a spatial aggregation algorithm that combines a general aggregation with spatial data and uses the Geohash and MapReduce operations to perform spatial social analysis, by using microblog data with the characteristics of a spatial social Web object. The proposed algorithm provides the foundation for a meaningful spatial social analysis.

• Proceedings of the KSRS Conference
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• v.1
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• pp.417-420
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• 2006

In these days, mobile application dealing with information contents on mobile or handheld devices such as mobile communicator, PDA or WAP device face the most important industrial needs. The motivation of this study is the design and implementation of mobile application using high resolution satellite imagery, large-sized image data set. Although major advantages of mobile devices are portability and mobility to users, limited system resources such as small-sized memory, slow CPU, low power and small screen size are the main obstacles to developers who should handle a large volume of geo-based 3D model. Related to this, the previous works have been concentrated on GIS-based location awareness services on mobile; however, the mobile 3D terrain model, which aims at this study, with the source data of DEM (Digital Elevation Model) and high resolution satellite imagery is not considered yet, in the other mobile systems. The main functions of 3D graphic processing or pixel pipeline in this prototype are implemented with OpenGL|ES (Embedded System) standard API (Application Programming Interface) released by Khronos group. In the developing stage, experiments to investigate optimal operation environment and good performance are carried out: TIN-based vertex generation with regular elevation data, image tiling, and image-vertex texturing, text processing of Unicode type and ASCII type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.505-513
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• 2017

In this study, we collected 200,578,703 geo-tweets and removed the twitter bots. Using the concept of activity radius, Twitter users are classified. Users are also divided first into domestic and overseas, and again domestic ones are divided into locals and non-locals. Statistical characteristics of activity strength and active area of Twitter users are described according to activity radius and home region, and the geographical distribution is presented visually. Through a case study of Las Vegas, we have identified the difference in activity strength and active area by the user's home residence. We expect to derive theories about human mobility by analyzing various cities with the method proposed in this study.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.165-171
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• 2017

Recently, the development and dissemination of smart devices linked to the network are being actively performed, and IOT(Internet of things) is issued form of mutually cooperative relationship through interoperation within smart devices. In this paper, we propose an innovative intelligent coffee shop management system by sharing and cooperatively controlling smart devices and Internet devices. The system can order smartphones including kiosk orders and beacon-based user identification. And it is a system that can make custom order without grasping user location information using geofence. The paper provides weather, temperature, time and user-based recommendation services based on Big Data. Therefore, the system is increased cost reduction and work efficiency than general coffee shops.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.330-334
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• 2005

Our country has both relics of long history and cultural inheritance as the resources of cultural sightseeing all over the country. Recently we found the lots of cultural assets in history by the survey of the sightseeing resources. Those are known to the people to give their values and semantics and the government makes on a lot of constant efforts. In this study, a system to investigate the path and to visit the location are developed by combining various gio-spatial data with the multimedia contents. This system provides people with guidance to and locating the cultural assets in the cyber space. The developed guide system is more convenient to provide people with the information and they are able to access the designated cultural assets of the nation easily. In addition, the contents are made by that people are able to use easily in the public area as well as on the internet.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.3-32
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• 2008

The potential deep geothermal resources span a wide range of heat sources from the earth, including not only the more easily developed, currently economic hydrothermal resources; but also the earth's deeper, stored thermal energy, which is present anywhere. At shallow depths of 3,000~10,000m, the coincidence of substantial amounts heat in hot rock, fluids that heat up while flowing through the rock and permeability of connected fractures can result in natural hot water reservoirs. Although conventional hydrothermal resources which contain sufficient fluids at high temperatures and geo-pressures are used effectively for both electric and nonelectric applications in the world, they are somewhat limited in their location and ultimate potential for supplying electricity. A large portion of the world's geothermal resource base consists of hot dry rock(HDR) with limited permeability and porosity, an inadquate recharge of fluids and/or insufficient water for heat transport. An alternative known as engineered or enhanced geothermal systems(EGS), to dependence on naturally occurring hydrothermal reservoirs involves human intervention to engineer hydrothermal reservoirs in hot rocks for commercial use. Therefore EGS resources are with enormous potential for primary energy recovery using an engineered heat mining technology, which is designed to extract and utilize the earth's stored inexthermal energy. Because EGS resources have a large potential for the long term, United States focused his effort to provide 100GW of 24-hour-a-day base load electric-generating capacity by 2050.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.415-421
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• 2009

TOA(time-of-arrival) and TDOA(time-difference-of-arrival) positioning techniques are commonly used in many radio-navigation systems. From the literature, it is known that the position estimate and error covariance matrix of TDOA obtained by GN(Gauss-Newton) method is exactly the same as that of TOA when the error source of the range measurement is only an IID white Gaussian noise. In case of geo-location and indoor positioning, however, multi-path or NLOS(non-line-of-sight) error is frequently appeared in range measurements. Though its occurrence is random, the multipath acts like a bias for a stationary user if it occurs. This paper presents the comparisons of error characteristics between TOA and TDOA positioning in presence of multi-path or NLOS error. It is analytically shown that the position estimate of TDOA is exactly the same as that of TOA even when bias errors are included in range measurements with different magnitudes. By computer simulation, position estimation error and error distribution are analyzed in presence of range bias errors.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.801-803
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• 2003

In this paper, we present a method for generating and providing spatially encoded video data that can be effectively used by GIS applications. We collect the video data by a mobile mapping system called 4S-Van that is equipped by GPS, INS, CCD camera, and DVR system. The information about spatial object appearing in video, such as occupied region in each frame, attribute value, and geo-coordinate, are generated and encoded. We suggest methods that can generate such data for each frame in semi-automatic manner. We adopt standard MPEG-7 metadata format for representation of the spatially encoded video data to be generally used by GIS application. The spatial and attribute information encoded to each video frame can make visual browsing between map and video possible. The generated video data can be provided and applied to various GIS applications where location and visual data are both important.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.5
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• pp.23-32
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• 2020

Recently, women's fear of crime continues to increase in space of everyday. By the way, the fear of crime has the spatial properties as crime. Therefore, The purpose of this study is to evaluate the spatial dependence of fear of crime and to suggest the physical environmental factors influencing fear of crime. For this, a spatial regression analysis using spatial weights was conducted based on the location data of the fear of crime measured through a survey. The results of this study are as follows; First, the fear of crime felt by women in their twenties who are vulnerable to crime has spatial dependence. Therefore, it is necessary to consider the spatial characteristics in analyzing the environmental factors affecting this. Second, in order to reduce the fear of crime, it is necessary to improve the environments of old housing and entertainment facilities. There is also a need for ongoing management. Third, careful consideration is needed in the installation of CCTV and street lights, which are factors influencing the fear of crime. It is necessary to establish a reasonable arrangement standard for CCTV and to analyze the street lighting in detail.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1489-1515
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• 2022

The number of interconnected real-world devices such as sensors, actuators, and physical devices has increased with the advancement of technology. Due to this advancement, users face difficulties searching for the location of these devices, and the central issue is the findability of Things. In the WoT environment, keyword-based and geospatial searching approaches are used to locate these devices anywhere and on the web interface. A few static methods of indexing and ranking are discussed in the literature, but they are not suitable for finding devices dynamically. The authors have proposed a mechanism for dynamic and efficient searching of the devices in this paper. Indexing and ranking approaches can improve dynamic searching in different ways. The present paper has focused on indexing for improving dynamic searching and has indexed the Things Description in Solr. This paper presents the Things Description according to the model of W3C JSON-LD along with the open-access APIs. Search efficiency can be analyzed with query response timings, and the accuracy of response timings is critical for search results. Therefore, in this paper, the authors have evaluated their approach by analyzing the search query response timings and the accuracy of their search results. This study utilized different indexing approaches such as key-words-based, spatial, and hybrid. Results indicate that response time and accuracy are better with the hybrid approach than with keyword-based and spatial indexing approaches.