• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1186-1192
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• 2012

In Jeju Smart Grid field test, Zigbee technology is being used as one of customer side solutions for AMI. Although Zigbee networks that provides effective connectivity and control among devices are advantages in ease of implementation and use, the data can be exposed to cyber attacks such as eavesdrop, unauthorized data dissemination and forgery. Currently authentication and confidentiality services are provided with the network and link keys generated based on public key pairs that are pre-installed in offline. However, the network is vulnerable once a hacker intrudes into a local network because operation and management policies for the generated keys are not well-established yet. In this paper, the vulnerability of the Zigbee security system in the customer side environment of Jeju Smart Grid field test is analyzed. Then, two-way authentication with the unique identifiers of devices and user-specific group management policies are proposed to resolve the vulnerability.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.513-515
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• 2003

COMS(Communication, Ocean and Meteorological Satellite), planned for launch in 2008, will be the first Korean ocean-meteorological geostationary satellite to provide capabilities for monitoring weather and ocean. Under the direction of Korean government, KARI(Korea Aerospace Research Institute) has the overall responsibility of COMS development project. The main development project was started in September 2003. In this paper, the overview of COMS development project and the conceptual design of the meteorological data service are introduced.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.872-885
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• 2015

The rapid increase of smart mobile devices and mobile applications has led to explosive growth of data traffic in cellular network. Offloading data traffic becomes one of the most urgent technical problems. Recent work has proposed to exploit opportunistic communications to offload cellular traffic for mobile data dissemination services, especially for accepting large delayed data. The basic idea is to deliver the data to only part of subscribers (called target-nodes) via the cellular network, and allow target-nodes to disseminate the data through opportunistic communications. Human mobility shows temporal and spatial characteristics and predictability, which can be used as effective guidance efficient opportunistic communication. Therefore, based on the regularity of human mobility we propose NodeRank algorithm which uses the encounter characteristics between nodes to choose target nodes. Different from the existing work which only using encounter frequency, NodeRank algorithm combined the contact time and inter-contact time meanwhile to ensure integrity and availability of message delivery. The simulation results based on real-world mobility traces show the performance advantages of NodeRank in offloading efficiency and network redundant copies.

• Proceedings of the KSRS Conference
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• v.2
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• pp.586-589
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• 2006

High resolution satellite imagery is regarded as one of the important data sets to engineering application, as well as conventional scientific application. However, despite this general view, there are a few target applications using this information. In this study, the possibility for the future wide uses in associated with smart graphics of this information is investigated. The concept of smart graphics can be termed intelligent graphics with XML-based structure and knowledge related to semantic web, which is a useful component for the data dissemination framework model in a multi-layered web-based application. In the first step in this study, high resolution imagery is transformed to GML (Geographic Markup Language)-based structure with attribute schema and geo-references. In the second, this information is linked with GIS data sets, and this fused data set is represented in the X3D (eXtensible 3D), ISO-based web 3D graphic standard, with styling attributes, in the next stop. The main advantages of this approach using GML and X3D are the flourished representations of a source data according to user/clients’ needs and structured 3D visualization linked with other XML-based application. As for the demonstration of this scheme, 3D urban modelling case with actual data sets is presented.

• International journal of advanced smart convergence
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• v.5 no.1
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• pp.1-7
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• 2016

Recently, introduced a cloud computing technology to the IT industry, smart phones, it has become possible connection between mobility terminal such as a tablet PC. For dissemination and popularization of movable wireless terminal, the same operation have focused on a viable mobile cloud in various terminal. Also, it evolved Wireless Sensor Network(WSN) technology, utilizing a Body Sensor Network(BSN), which research is underway to build large Ubiquitous Sensor Network(USN). BSN is based on large-scale sensor networks, it integrates the state information of the patient's body, it has been the need to build a managed system. Also, by transferring the acquired sensor information to HIS(Hospital Information System), there is a need to frequently monitor the condition of the patient. Therefore, In this paper, possible sensor information exchange between terminals in a mobile cloud environment, by integrating the data obtained by the body sensor HIS and interoperable data DBaaS (DataBase as a Service) it will provide a base of mBodyCloud System. Therefore, to provide an integrated protocol to include the sensor data to a standard HL7(Health Level7) medical information data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.6
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• pp.2078-2094
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• 2015

Now a days, Efficient processing of Broadcast Queries is of critical importance with the ever-increasing deployment and use of mobile technologies. BQs have certain unique characteristics that the traditional spatial query processing in centralized databases does not address. In novel query processing technique, by maintaining high scalability and accuracy, latency is reduced considerably in answering BQs. Novel approach is based on peer-to-peer sharing, which enables us to process queries without delay at a mobile host by using query results cached in its neighboring mobile peers. We design and evaluate cooperative caching techniques to efficiently support data access in ad hoc networks. We first propose two schemes: Cache Data, which caches the data, and Cache Path, which caches the data path. After analyzing the performance of those two schemes, we propose a hybrid approach (Hybrid Cache), which can further improve the performance by taking advantage of Cache Data and Cache Path while avoiding their weaknesses. Cache replacement policies are also studied to further improve the performance. Simulation results show that the proposed schemes can significantly reduce the query delay and message complexity when compared to other caching schemes.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.22-33
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• 2006

The objective of this paper is to discuss geographic information policies and strategies of British government and suggest effective policies for Korea National GIS project GIS that has been implemented geographic information infrastructures into public sectors and private markets for the last ten years. To obtain the research aim, this paper reviews the main factors of the Britain GIS project such as distribution structure and process of GI markets, government policies and strategies that are led by Ordnance Survey, most leading mapping agency in the UK. In conclusion, some issues have been explored with reference to the experiences of the Britain GIS projects. The first of these is the nature of geographic information and the second concerns the notion of the circulation policies of spatial data, and the last proposes Korea GIS policies and strategies for successful geographic information and spatial data implementation. The findings of the analysis of the Britain GIS development indicate that a shift began to take place from central government coordinate toward more extensive utilization of private and commercial sectors. This reflects both the increasing importance of geospatial data circulation in all levels of GIS stakeholders. Finally these discussions are particularly to be the issues where multi-agency collaboration of Korea government is concerned and can take the form of joint ventures by consortiums of both involving data producers and data users in order to increase commercial participation for value-added geospatial items, and to encourage both research and development sectors with low or free price policies.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.239-246
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• 2017

Communications for mobile sink groups such as rescue teams or platoons bring about a new challenging issue for handling group mobility in wireless sensor networks. Recently, a group region-based approach has been proposed to send data to a mobile sink group. However, it uses excessive flooding for 3 steps (group region discovery, region information notification, and data dissemination) to support mobile sink group. Thus, it causes high energy consumption and data delivery failure. Moreover, its per-sink mobility supporting scheme makes energy consumption and data delivery failure more serious. Thus, this paper proposes an Energy-efficient and Reliable Mobile Group communication protocol (ERMG) to support a mobile sink group, which exploits a virtual grid structure. For the group region discover and notification and the data dissemination, ERMG uses communications with only cell heads of grid cells that manages group sinks. ERMG also uses a per-grid based scheme to support sink mobility. Simulation results show that ERMG has 30% less energy consumption and 6% more desired delivery deadline success ratio than the existing protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.281-290
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• 2014

The real-time data dissemination schemes exploit the spatiotemporal commuication approach which forwards data at the delivery speed calculated with the desired time deadline and the end-to-end distance in wireless sensor networks (WSNs). In practical environments, however, the performance of the real-time data dissemination might be degraded by additional and inevitable delay due to some holes. Namely, the holes lengthen the data delivery path and the spatiotemporal approach could not estimate a distance of the data delivery path. To deal with this, we propose A Hole Self-Organization Real-time Routing Protocol for Irregular Wireless Sensor Networks. In proposed protocol, nodes around holes could detect them at deploying phase. A hole is represented as a circle with center point and radius. This hole information is processed and provided as a form of location service. When a source queries a destination location, location provider replies certain points for avoiding holes as well as destination location. Thus, the source could set desired speed toward the destination via the points. Performance evaluation shows that provides better real-time service in practical environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.410-415
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• 2007

Recent advances in sensor network technology have open up challenges for its effective routing. Routing protocol receives most of the attention because routing protocols might differ depending on the application and network architecture. In the rapidly changing environment and dynamic nature of network formation efficient routing and energy consumption are very crucial. Sensor networks differ from the traditional networks in terms of energy consumption. Thus, data-centric technologies should be used to perform routing to yield an energy-efficient dissemination. By exploiting the advantages of both ant colony optimization techniques in network routing and the ability of data centric muting to organize data for delivery, our approach will cover features for building an efficient autonomous sensor network.