• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.506-514
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• 2008

At coverage boundaries of cellular systems including the recent WiBro standard which operate with full frequency reuse for increased spectral efficiency, interference signals from the base stations(BS) of adjacent cells degrade the receiver performance. In this paper, a detection method for multiple-antenna mobile stations(MS) is proposed for downlink performance improvement at coverage boundaries of cellular systems. For the performance verification, we obtain the probability density function(pdf) of the effective signal-to-interference and noise ratio(SINR) according to the variation of the interference signals from adjacent cells as well as the number of MS antennas, and calculate the transmission efficiency. We also verify the performance of proposed method with simulation results, to demonstrate a significant performance improvement is achieved over the maximal ratio combining(MRC) and spatial demultiplexing(SD) methods in terms of the effective SINR and the spectral efficiency.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.13-21
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• 2009

Digital map should have the up-to-dateness as well as the accuracy to perform a role as the national spatial data. As digital mapping process require aerial photograph, surveying, and field working, it consumes a lot of time and cost. So there is a limit to maintain the up-to-dateness. If we updates the digital map frequently by using the as-built drawings, we can prevent the waste of national budget by reuse of existing drawings and make accuracy updates from existing survey results. In spite of this advantages, due to insufficiency of CAD drawing standard, inconsistency of file types of as-built drawings and digital maps, and topology relations between input features and original features, so the frequent updates using the as-built drawings is on the difficult situation to perform. In this research, first, CAD features extracted from as-built drawings land the new/update whether original features exist or not and generate topology from spatial relation of features. Second, suggest the efficient partial-update-plan performing integrity test. As a result, guarantee the accuracy and the up-to-dateness of digital map.

• Journal of Korean Society of Rural Planning
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• v.20 no.1
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• pp.161-173
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• 2014

This study aimed to adaptive reuse plan a take advantage of Suncheon Bay Garden Expo 2013. Detailed objectives included: to identify and foster cultural and ecological resources in Suncheon Bay and Garden Expo Site; and to search and propose characterized program in the site for efficient utilization; and to revitalize a site for the vitalizations of the region where garden culture and garden industries for strengthening local competitiveness. The study was multi-phased. The first stage included basic surveys such as site status and environmental context analysis, and questionnaires and similar case studies, and the second stage was to review the direction of preliminary planning, develop associated industries and strategies for regional revitalization and review and incorporate project details. And the third stage aimed to develop a comprehensive plan from spatial plans and program plans and suggest plans to vitalize the operation of the site. The results of the study are as follows: First, the characterization strategy is 'healing experience tourism', 'healing garden', 'healing herbal care' are suitable for the site and regional revitalization. Second, the dimension of 2013 Suncheon Bay Garden Expo which was distinguished into four areas, in consideration of the characteristics and contents of the garden expo site for efficient operation and maintenance. Four area are as follows: the park oriented area, the experiential tourism oriented area, the existing conservation oriented area, and the area for associated industries. Third, the practice of private and public partnerships is needed in order to efficiently manage and operations. The significance of this study is that it is seeking to take advantage of the Garden Expo site and set the plan by existing resources and in consideration of local characteristics, in conjunction with area to envision and proposed management plan. Some problems are remained which have not been able to deal with details program and organization and financial planning programs for the operation of the site. This is for further study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1457-1467
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• 2015

Depending on the type of Tx-Rx pairs, VHF Data Exchange System (VDES) for maritime communication is expected to employ the different frequency channels. Load imbalance between the different channels turns out to be a critical problem for the multi-hop communication using Ad-hoc Self-Organizing TDMA (ASO-TDMA) MAC protocol, which has been proposed to provide the connectivity between land station and remote ship stations. In order to handle the inter-channel load imbalance problem, we consider a model of the stochastic geomety in this paper. After analyzing the spatial reuse efficiency in each hop region by the given model, we show that the resource utility can be maximized by balancing the inter-channel traffic load with optimal resource allocation in each hop region.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.259-266
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• 2011

Femtocells are expected as the surest way to increase the system capacity with higher-quality links and more spatial reuse in future networks. In spite of their great potential, the system capacity is highly susceptible to network density because a large portion of users are exposed to inter-cell interference (ICI). In this work, we proposed a dynamic interference avoidance scheme in densely deployed cell environments. Our proposed DDIA (Distributed Dynamic ICI Avoidance) scheme not only works in a fully distributed manner, but also controls interference link connectivity of users with high agility so that it is suited for self-organizing networks (SONs). We introduced the concept of ICI-link and two-tier scheduling in designing the DDIA scheme. To avoid ICI without any central entity, our scheme tries to harmonize all base stations (BSs) with users adaptively. Through extensive simulations, it was shown that our proposed scheme improves the throughput of users by more than twice on average compared to the frequency reuse factor 1 scheme, who are exposed to ICI while maintaining or even improving overall network performance. Our scheme operates well regardless of network density and topology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.239-250
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• 2022

LoRa is a physical layer technology designed to secure highly reliable long-range communication with introducing loco parentis tree network and chirp spreading spectrum. Since since a leaf can send message to more than one parents simultaneously with a single transmission in a region, packet delivery ratio increases logarithmically as the number of gateways increases. The delivery ratio, however, dramatically collapses even under loco parentis tree topology due to the limitations of ALOHA-like primitive MAC, . The proposed method is intended to exploit SDMA approach to reuse frequency in an area. With the view, TxPower of each sender for each message in a concurrent transmission is elaborately controlled to survive the collision at different gateway. Thus, the gain from the capture effect improves the capacity of resource-hungry Low Power and Wide Area Networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.194-198
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• 2021

LoRa is a physical layer technology that is designed to provide a reliable long-range communication with introducing CSS and with introducing a loco parentis tree network. Since a leaf can utilize multiple parents at the same time with a single transmission, PDR increases logarithmically as the number of gateways increases. Because of the ALOHA-like MAC of LoRa, however, the PDR degrades even under the loco parentis tree topology similarly to the single-gateway environment. Our proposed method is aimed to achieve SDMA approach to reuse the same frequency in different areas. For that purpose, it elaborately controls each TxPower of the senders for each message in concurrent transmission to survive the collision at each different gateway. The gain from this so-called capture effect increases the capacity of resource-hungry LPWAN. Compared to a typical collision-free controlled-access scheme, our method outperforms by 10-35% from the perspective of the total count of the consumed time slots. Also, due to the power control mechanism in our method, the energy consumption reduced by 20-40%.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.1-16
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• 2006

Recently, human based computing environment for supporting users to concentrate only user task without sensing other changes from users is being progressively researched and developed. But middleware deletes steream data processed for reducing process load of massive information from RFID sensor in this computing. So, this kind of middleware have problems when user demands probability or statistics needed for data warehousing or data mining and when user demands very important stream data repeatedly but already discarded in the middleware every former time. In this paper, we designs Sensor Middleware Architecture on Multi Level Spatial DBMS with Snapshot and manage repeatedly required stream datas to solve reusing problems of historical stream data in current middleware. This system uses disk databse that manages historical stream datas filtered in middleware for requiring services using historical stream information as data mining or data warehousing from user, and uses memory database that mamages highly reuseable data as a snapshot when stream data storaged in disk database has high reuse frequency from user. For the more, this system processes memory database management policy in a cycle to maintain high reusement and rapid service for users. Our paper system solves problems of repeated requirement of stream datas, or a policy decision service using historical stream data of current middleware. Also offers variant and rapid data services maintaining high data reusement of main memory snapshot datas.

• Spatial Information Research
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• v.8 no.1
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• pp.15-29
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• 2000

In the Recent rapidly changing technology environment the computerization of administration business which is driven or will be driven to give improved information services to people by local government or central government with a huge budget. The possibility of applying GIS application component to the computerization of administration business is investigated to prevent local government from investing redundant money and to reuse the existing investment at this point of time. Land civil service application component was developed at the $\ulcorner Development of Open GIS Component S/W \lrcorner$ project which was managed by Ministry of Information and Communication . GIS application component was based on Open GIS OLE/COM specification for development of standard interface and USD(Unified System Development ) for development method and UML (Unified Modeling Language) for system design and Visual C++ for component implementation. Implemented components were Process Control, Map, Print, Statistics component and were verified by using Visual Basic and Delhi. tis study shows that the development of component is very useful at the GIS application development for local governments. But the standard of business and data and system is the essential prerequisite to maximize business application.

• Journal of Korea Spatial Information System Society
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• v.3 no.1 s.5
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• pp.37-48
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• 2001

ITS includes an Advanced Traveler Information System(ATIS) that provides travelers with service and facility data for the purpose of assisting prior to embarking on a trip or after the traveler is underway. ATIS consists of three major subsystems, which are a Pre-trip Traffic Information subsystem(PTIS), an En-route Traffic Information Subsystem(ETIS), and a Dynamic Route Guide Subsystem(DGIS). ATIS needs to be designed and implemented in accordance with the National ITS Architecture, a reference framework that spans all of standards activities. Recently, as software technology is rapidly improved and stabilized, there are some needs to reuse pre-developed and powerful ITS technology. ITS standardization based on components and open interfaces becomes a way to solve these reusability of current ITS technology. This paper focuses on how could we design and implement ATIS based on the component with the aid of UML(Unified Modeling Language). The UML methodology is expected to provide a standardized model for newly developed ITS components.