• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.36-40
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• 2008

SIMS manages data for various spatial and non-spatial as integral management system to support space information administration environment and support several application works. Without being limited to spatial data that existent spatial Data Mining question language advances handling in this paper, did so that can find useful information from various data connected with automatically data collection, artificial satellite side upside service, remote sensing, GPS. Mobile Computing and data about Spatio-Temporal. Also, we designed spatial Data Mining query language that support a spatial Data Mining exclusive use system based on SIMS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.89-94
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• 2006

DGPS provides less altitude accuracy than horizontal accuracy according to geometric characteristics of GPS satellite arrangement. To assist DGPS altitude measurements, two barometric altitude sensors were used and set up at the mobile and the reference station respectively to get the differential altitude. This differential altitude is coupled with the DGPS altitude measurement by a Kalman filter so that the improved altitude is estimated. The differential altitude is based on the relative altitude measurement but results in providing the absolute altitude. The precision of this differential altitude is verified by experiments in accordance with a baseline length.

• Information and Communications Magazine
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• v.23 no.2
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• pp.23-40
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• 2006

재난은 다양한 원인에 의하여 예측 불가능하게 발생되고 있다. 정보화의 진전에 따라 네트워크는 모든 경제활동의 근간이 되어 있으며, 재난이 발생하면 재난복구 및 구난 활동 등에 통신기능의 활용도가 더욱 높아진다. 특히 통신 장애를 일으키는 통신재난이 발생하면 그 파급효과는 빠르고, 넓게 확산되는 경향을 보인다. 국내.외적으로 국가 주요 활동의 정보통신의 의존도가 증가하고, 정보통신 기반의 복잡도와 개방성이 증가하여 위협 및 취약성이 증대하며, 정보전(cyber warfare)의 공격 위협이 증대하는데 비교하여, 통신 부문의 민영화에 따라 공공 부문 보호 영역이던 통신 부문이 민간 부문으로 확대되어 다양한 위협에 노출되어 있는 실정이다. 따라서 최근에는 통신 네트워크와 서비스를 정보통신 시스템과 서비스에 대한 독립적인 보호와 보안이라는 차원에서 한걸음 더 나아가 " 국가주요 기반 구조에 대한 보호와 위협에 대한 종합적인 대응 " 이라는 차원에서 접근하고 있다. 미국은 지난 및 비상대비 통신 전담기구인 NCS(National Communication System)와 대통령자문위원회인 NSTAC(National Security Telecommunication Advisory)등 종전부터 있던 통신 재난 및 비상 통신 관련 기구에서 진행해오던 통신 재난 및 비상 통신 관련 기구에서 진행해오던 통신 재난 및 비상 통신 관련 업무를 9-11 사태를 경험하면서 신설된 Department of Homeland Security에서 총괄하도록 하고 있다. 캐나다의 경우는 MSAT(Mobile Satellite Services) Emergency Telecommunication Network을 통한 긴급통신 시스템을 구축하였다. 일본의 경우 우정성(현재는 총무성에 통합) 산하 비상통신협의회를 구성하여 비상통신에 관련한 협의와 점검을 추진하며 방재용 무선 시스템을 구축 운용하고 있다. 본 고에서는 이와 같은 비상통신과 관련하여 수행하고 있는 국외 비상통신 관련표준화 현황 및 해외 주요국가 별 구축 동향에 대해서 기술한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.565-567
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• 2018

The rover acquires its own position information using satellites signals provided by several satellites(at least four or more). For the present, GNSS systems are widely used in various fields. However, there are many factors that cause accuracy errors in positioning between rovers and GNSS satellites. Due to satellite time error, orbit error, ionospheric & convective refraction, multipath, etc., rover can't acquire precise position. Differential GPS(DGPS) and Real-Time Kinematic(RTK) have been developed as compensation techniques to reduce such errors. In this paper, we intend to develop a terminal with RTK technique to acquire precise position information of mobile station.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5C
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• pp.485-497
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• 2009

In this paper, we described DVB-S2 system for mobility. cross layer coding technique are needed to maintain the performance in deep fading channel. Cross layer coding is divided into two kinds of level. First level is Physical layer coding and, second layer is link layer or upper layer coding. Fixed on DVB-S2 short frame coding method as a physical layer, we simulated the various coding method as an upper layer coding. Furthermore, we analyzed the performance of each coding method on according to mobile vehicle speed, data rate, interleaving memory size, and IP packet size.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.67-76
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• 2000

In this paper, a low noise amplifier has been developed, which is operating at L-band i.e., 1525-1575 MHz. By using resistive decoupling circuits, the resistor dissipates undesired signal in low frequency band. By adopting this design method the stability of the LNA is increased and the input impedance matching is improved. The LNA consists of the low noise GaAs FET ATF-10136 and the internally matched VNA-25. The low LNA is fabricated by both the RP circuit and the self-bias circuits in an aluminum housing. As a result, the characteristics of the LNA implemented show more than 32 dB in gain, lower than 0.5 dB in noise figure, 18.6 dBm output gain in 1 dB gain compression point.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1774-1784
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• 1993

This paper presents the design, fabrication and measured results of the broadband microstrip array with a conical radiation pattern and the circular array composed of six square microstrip antenna elements. Each element antenna has the stacked structure with a parasitic element to achieve a broadband characteristic and a branch line quadrature hybrid is attached to it for the circular polarization. The design procedures and measured results of the scheme for obtaining the conical radiation pattern which is useful for the mobile communication via the satellite. Finally, the performance of the fabricated antenna is measured and compared with the theory.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2227-2234
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. An upper layer, including erasure Reed-Solomon error correction combined with cyclic redundancy check. However, a critical factor must be considered in upper layer decoding. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. If, for example, there is one real byte error, in an IP packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed upper layer decoding methods; LLR-based decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.

• Korean Journal of Remote Sensing
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• v.23 no.5
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• pp.401-408
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• 2007

Animated anaglyph is the most cost-effective method for 3D stereo visualization of virtual or actual 3D geo-based data model. Unlike 3D anaglyph scene generation using paired epipolar images, the main data sets of this study is the multi-typed 3D feature model containing 3D shaped objects, DEM and satellite imagery. For this purpose, a prototype implementation for 3D animated anaglyph using OpenGL API is carried out, and virtual 3D feature modeling is performed to demonstrate the applicability of this anaglyph approach. Although 3D features are not real objects in this stage, these can be substituted with actual 3D feature model with full texture images along all facades. Currently, it is regarded as the special viewing effect within 3D GIS application domains, because just stereo 3D viewing is a part of lots of GIS functionalities or remote sensing image processing modules. Animated anaglyph process can be linked with real-time manipulation process of 3D feature model and its database attributes in real world problem. As well, this approach of feature-based 3D animated anaglyph scheme is a bridging technology to further image-based 3D animated anaglyph rendering system, portable mobile 3D stereo viewing system or auto-stereo viewing system without glasses for multi-viewers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.525-528
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• 2009

This paper attempts to conceptually examine the potential of IPTV(Internet Protocol Television). First, this paper reviews the concept of a bridging telecommunication service and a gap-filling telecommunications service. Second, the current status of various emerging telecommunications services including mobile WiMax, called WiBro, and both satellite and terrestrial digital multimedia broadcasting service, called DMB are comprehensively analyzed. Based on those analysis, this paper analyzes whether IPTV is regared as a bridging telecommunications service or a gap-filling telecommunications service and examine the potential growth possibility of IPTV. Finally, the suggestions for policy makers are discussed.