• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.42-54
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• 2002

In December of 1997, Korea Aerospace Research Institute begin to develope the conceptual design of Kompsat2 as the Kompsat1 design is nearly completed. Basic direction of this design was set up to utilized the heritage of Kompsat1 and modify the payload module to accommodate the new high resolution space borne camera. And in the early stage of this design, total system configuration design study was conducted based on 1st level payload information. In this paper, mechanical system design at various stage is documented and this will be used as a path finder or guidelines in the future feasibility study or conceptual design.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.533-540
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• 2014

We propose an age estimation-based smart digital signage for the next-generation airport service. The proposed system can recognize the face of the customer so that it can display the selective information. Using a webcam, the system captures the face of the customer and estimates the age of the customer by calculating the wrinkle density of the face and applying bayesian classifier. The developed age estimation method is tested with a face database for the performance evaluation. We expect the new digital signage may improve the satisfaction of customers of the airport business.

• Journal of Satellite, Information and Communications
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• v.3 no.2
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• pp.1-6
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• 2008

Space-time codes (STC) can achieve the diversity gain in a multi-path environment without additional bandwidth requirement. Recent study results reported that satellite systems can also achieve this diversity gain by using space-time codes in a cooperative network with terrestrial repeaters. Due to uni-directional nature of satellite DMB services, transmit diversity can be considered as one of the most effective ways to improve the performance. In this paper, we demonstrate various simulations results of STC schemes which can contribute to improve performance of future satellite DMB services. The STC schemes introduced in this paper provides diversity gains by combing independent coded signal from the satellite as well as from the terrestrial repeaters. In addition, we discuss a few points which should be considered to develop and implement these STC schemes.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.43-57
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• 2006

Next-generation mobile communication systems evolve in the form of high speed data transmission along with integration of wired-wireless network. Therefore, it needs researches on integrating service to heterogeneous networks to offer high speed data transmission and various services while supporting user mobility. In existing studies, heterogeneous networks are linked to single core network separatively, Since vertical handoff between heterogeneous networks leads to some delay, packets may be lost during vertical handoff. To solve this problem, this paper proposes an hierarchically integrated network architecture considering the characteristics of CDMA2000, WiBro, and WLAN. The hierarchically integrated networks are overlaid according to coverage of each network. Therefore, the proposed architecture can minimize handoff delay and packet loss. In addition, this paper proposes an integrated framework for next generation mobile communication networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4A
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• pp.385-392
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• 2006

It is widely accepted that high user densities in mobile multimedia environments can only be achieved with micro- and pico-cell. The smaller cell size causes frequent handovers between cells, and decreases permissible handover processing delay. This may result in the handover failure, in addition to the loss of some packets during the handover. In these cases, re-transmission is needed in order to compensate errors, which in turn triggers a rapid degradation of throughput. In this paper, we propose a new handover scheme for the next generation mobile communication systems, in which the handover setup process is done in advance before a handover request by predicting the handover cell based on mobile terminal's current position and moving direction. Simulation is performed in order to analyze the handover failure rate and packet loss rate. Simulation results show that our proposed method provides a better performance than the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2533-2540
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• 2009

Performance of processing protocols is one most important goal in a network or systems constituting the network. Measurement of performance, thus, is an essential element to not only establish the network but also develop systems. A projection in vector mathematics is the transformation of points and lines in one plane onto another plane by connecting corresponding points on the two planes with parallel lines. This is a method, as an application of vector mathematics, which is widely used in engineering as well to consider elements dedicated to the measurement object. This paper proposes a sound methodology for measuring the performance of the SIP protocol, which is based on the projection. The SIP protocol is a typical standard protocol for call-processing in the internet telephony of Next Generation Convergence Network. Owing to use the projected protocol which excludes unnecessary operation paths, the methodology can be effective in implementation and resource utilization. This paper also presents a process based on the proposed methodology to measure the performance of a SIP proxy server.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.97-103
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• 2014

In order to verify normal operation of satellite OBC(On Board Computer), it is essential that processor monitoring and debugging. So we are using the GRMON of Aeroflex Gaisler. It provides a lot of features for debugging of LEON processor but we can't use that features on the NGSCB(Next Generation Spacecraft Computer Board) except a few things. So the cost-effectiveness is very low. And for hardware fault injection, we are using a method of modify satellite flight software, because we can't modify GRMON. This method can not guarantee normal operation of the satellite flight software. So in this paper we were developed the processor monitoring and fault injection tool for NGSCB.

• The Journal of the Korea Contents Association
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• v.2 no.2
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• pp.36-41
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• 2002

In a mediator based information integration system that integrates information distributed on various data sources as a common data model, there are many researches on a common data mode providing a reservation of integrated data semantic, and on a resolution for a conflict caused by integrating various data modes. This paper proposes the DataBlender system that minimizes the semantic losses and provides an easy resolution for a conflict using the XML technology like as XML Schema, XQuery. Futhermore, it provides an integrated query facility usable in the mobile environment. So it becomes a foundation for a next Internet business environment.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.255-266
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• 2009

The Semantic Web has appeared to handle information on the web effectively, which has been increasing very rapidly since the web emerged. It refers to the machine, which understands the meaning of information on behalf of human and handles the information automatically that users want. The objective of this research is to help people to understand the Semantic Web as the next generation web by surveying the applications of Semantic Web technologies. To that end, this paper suggests a system framework which can be used for analyzing most of the Semantic Web applications. Using the suggested the framework, the recent Semantic Web applications are analyzed. And then research challenges are discussed to be overcome for the practical Semantic Web based on the analyzed results.

• The Journal of Information Systems
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• v.15 no.4
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• pp.1-22
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• 2006

Nowadays, IS projects are getting more complicated and large-scaled. Therefore, many researchers and practitioners have been interested in the IS development methodologies, automated tools, techniques, and TQM to improve IS performance. Latest Standish Group's research reported that after the PMO introduction, project scale became bulkier than 1 or 2 year ago, and that IS development project success probability was increased sharply by 62 percents from 37. The previous researches listed just various PMO functions. This research is to seize the core functions and management level of the PMO affecting on the IS project performance with banks which are the leading industry to accept the PMO in Korea. The activities in the categories of implementation management technology support management infrastructure management are the core functions of the PMO to affect the IS performance including schedule management quality management user and stakeholders' satisfaction. Also, the PMO management level is important for IS project success. Among the 5 levels PMI suggested, PMO can implement the project effectively at least at the third level. Korean companies which are about to introduce the PMO have to consider the PMO core functions and management level to increase the IS maturity.