성층권 통신에서 페이딩 채널 모델과 BPSK 시스템의 성능에 관한 연구

안도섭(Do-Seob Ahn),구본준(Bon-Jun Ku),유문희(Moon-Hee You),강병권(Byeong-Gwon Kang) 한국통신학회 2000 한국통신학회 학술대회논문집 Vol.2000 No.11

Data envelopment analyses on evaluating efficiencies of satellite communication and broadcasting R&D outcomes in Korea

안재경,안도섭,구본준,Ahn, Jae-Kyoung,Ahn, Do-Seob,Ku, Bon-Jun Korea Society of Satellite Technology 2008 한국위성정보통신학회논문지 Vol.3 No.2

Traditionally R&D evaluation has been performed by experts who can understand the contents of the study area very well. Recently extensive application of quantitative evaluation methods have been attempted for introducing the administrative management system that poses greater importance on records and results. More objective reviews on the R&D outcomes are called for gaining public supports. In this paper a bibliometrical analysis is to be performed to evaluate satellite communication and broadcasting public R&D outcomes for last 7 years. Data envelopment analysis method is selected for evaluating the efficiencies of multiple outputs (papers, patents, royalties, technology transfers) where multiple inputs (number of researchers and R&D expenses) are given. R&D outcomes from 22 research institutes are being compared and satellite communication and broadcasting R&D efforts turn out to be highly efficient.

위성 DMB 시스템 성능 분석 및 보호비 설정

송영준,안도섭,오우진,Song Young-Joon,Ahn Do-Seob,Oh Woo-Jin 한국전자파학회 2004 한국전자파학회논문지 Vol.15 No.9

In this paper we analyze the satellite DMB system E using CDM/QPSK transmission system in 2,630~2,655 MHz(25 MHz) bandwidth by computer simulation. Based on this result, we propose the protection ratio analysis and values to guarantee the Performance of the satellite DMB system E from the interference of CATV using the same spectrum. As a result, we confirmed that the protection ratio between DMB and wireless CATV should be guaranteed -16.3 dB in AWGN channel and -11.3 dB in Rician Fading(Channel model A) channel. These research results can be important fundamental material for the commercialization of satellite DMB system.

위성 OFDMA Downlink에서 PAR을 최소화 하기 위한 사용자 부채널 할당 및 채널 보상 기법

김한나,최권휴,안도섭,강군석,김희욱,Kim, Han-Nah,Choi, Kwon-Hue,Ahn, Do-Seob,Kang, Kun-Seok,Kim, Hee-Wook 한국위성정보통신학회 2009 한국위성정보통신학회논문지 Vol.4 No.1

We investigate the adaptive channel attenuation compensation of satellite OFDMA downlink users for minimum PAR (Peak to Average power Ratio), which is one of the main challenging issues in satellite OFDMA application. First, we analyze and compare PAR performances of two main different channel attenuation compensation schemes for OFDMA, i.e., PC-OFDMA (power control OFDMA) and AMC-OFDMA (Adaptive Modulation and Coding). While AMC-OFDMA maintains the constant transmission powers through entire user data subcarriers, PC-OFDMA has non-uniform subcarrier transmission powers because subcarrier powers are separately controlled to compensate each user's sub-channel attenuation. We newly found the fact that non-uniform subcarrier power in PC-OFDMA achieves rather reduced PAR compared to AMC-OFDMA and the amount of reduction becomes larger as the power differences among subcarriers increase. Also, there is an additional PAR reduction in PC-OFDMA by optimizing subcarrier grouping scheme for user's sub-channelization.

TBO 지원을 위한 4D 나래기상 데이터 플랫폼 서비스

김지연,김상일,안도섭,최훈,Jiyeon Kim,Sang-il Kim,Do-Seob Ahn,Hoon Choi 대한원격탐사학회 2025 대한원격탐사학회지 Vol.41 No.1

국제민간항공기구(International Civil Aviation Organization, ICAO)는 궤적기반운항(Trajectory-Based Operations, TBO)을 통해 항공교통의 안전성과 효율성을 향상시키기 위한 기술 개발의 중요성을 강조하고 있다. 이에 본 연구는 한국에서 개발 중인 나래기상 시스템과 그 핵심 구성 요소인 4D-Wx Application Programming Interface (API) 배포 서비스를 중심으로 항공 운항 지원을 위한 기상정보 제공 방안을 제시한다. 나래기상 시스템은 다양한 기상 데이터를 통합하여 4D 궤적(Trajectory Based, 4DT), 관심 영역(Region of Interest, ROI), 특정 지점(Point of Interest, POI)에 최적화된 기상 예측 데이터를 표준화된 형식으로 제공함으로써 맞춤형 항공 운항 지원을 가능하게 한다. 본 논문에서는 4D-Wx API 서비스 범위와 기술적 가능성을 평가하고, 이를 기반으로 항공 운항의 안전성과 효율성을 증진할 수 있는 시스템 개발 방향을 제안하였다. 특히, API를 통해 궤적 기반 운항을 지원하기 위한 실시간 기상정보의 제공 효과를 분석하였다. The International Civil Aviation Organization (ICAO) emphasizes the importance of developing technologies to enhance the safety and efficiency of air traffic through trajectory-based operations (TBO). In this context, this study focuses on the NARAE-Weather system, currently under development in Korea, and its core component, the 4D-Wx Application Programming Interface (API) distribution service, to propose an approach for providing aviation weather information to support air traffic operations. The NARAE-Weather system integrates diverse meteorological data to deliver standardized weather forecasts optimized for trajectory based (4DT), regions of interest (ROI), and points of interest (POI), enabling customized aviation operation support. This paper evaluates the service scope and technical feasibility of the 4D-Wx API and outlines a direction for supporting air traffic operations through the provision of multidimensional weather information. Specifically, the study examines the effectiveness of delivering real-time weather information via the API to support trajectory-based operations.

The introductory study for MIMO techniques over satellite systems

강연수,강군석,안도섭,Kang, Yeon-Su,Kang, Kun-Suk,Ahn, Do-Seob Korea Society of Satellite Technology 2007 한국위성정보통신학회논문지 Vol.2 No.2

In this paper, the introductory study of the multi input multi output (MIMO) techniques for satellite communication systems is presented. Because of the advantage of wide coverage of satellite, it has been considered for broadcasting services and fill-in services. On the other hand, state of the art multi input multi output (MIMO) techniques such as space time code (STC) and spatial multiplexing (SM) makes the terrestrial system increase link performance and their coverage, and also increase the link throughput. For these regard, in order to satisfy the requirements of the next generation communications and coexists with terrestrial systems harmoniously, the studying about satellite MIMO techniques is necessary. In this paper, we introduce some system model and scenarios to apply MIMO technique to intermediate module repeater (IMR). The possibility of these techniques and technical requirements are also considered. Especially, Space time code is used to enhance IMRs coverage and increase the link performance, and space time multiplexing is utilized to multiplex satellite broadcasting signals with local broadcasting signal in IMR cell.

톤 예약 기법과 DCT 변환을 이용한 OFDM 시스템의 PAPR 저감과 BER 분석

변희섭,신병철,안도섭,Byeon, Heui-Seop,Shinn, Byung-Cheol,Ahn, Do-Seob 한국전자파학회 2006 한국전자파학회논문지 Vol.17 No.10

OFDM system is very useful for the high speed communication system. However, OFDM system has a serious problem of high PAPR that results from the so many subcarriers in the same phase. This OFDM signal is distorted through the nonlinear HPA(High Power Amplifier). Tone reservation method is to insert tone signal in several types to reduce the PAPR after iterating this process by changing the tone signal. Also discrete cosine transform(DCT) can reduces the PAPR as multiplying the cosine value to change the angle and mix up with the data. In the paper, the combination of the TR method and DCT method is newly proposed for more effective reduction of the PAPR. Simulation results show that the proposed method outperforms the conventional simple TR method and DCT method with respect to the PAPR reduction and BER performance.

An Economic Feasibility Analysis of the HAPS Services in Korea

안재경,김종화,이덕두,안도섭,구본준,Ahn, Jae-Kyung,Kim, Jong-Hwa,Lee, Deok-Joo,Ahn, Do-Seob,Ku, Bon-Jun 한국위성정보통신학회 2006 위성통신과 우주산업 Vol.13 No.1

HAPS(High Altitude Platform Station) which is defined as a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the earth is promising technology capable of providing broadband multimedia services. In this study, economical aspects of HAPS service are analyzed by estimating the revenue and costs incurred by the service. To evaluate the profitability of HAPS service, the number of subscribers is estimated and then the net present value (NPV), payback period, and the rate of return on investment (ROI) are calculated under various scenarios

산불 후 식생 회복 모니터링을 위한 Sentinel-2 위성영상의 RGB 합성기술

김상일 ( Sang-il Kim ),안도섭 ( Do-seob Ahn ),김승철 ( Seung-chul Kim ) 대한원격탐사학회 2021 대한원격탐사학회지 Vol.37 No.5

Monitoring of post wildfire provides important information for vegetation restoration. In particular, remote sensing data are known to provide useful information necessary for monitoring. However, there are insufficient research results which is monitoring the vegetation recovery using remote sensing data. This study is directed to monitoring post-wildfire vegetation restoration. It proposes a method for monitoring vegetation restoration using Sentinel-2 satellite data by compositing Tasseled Cap linear regression trend in a post wildfire study sites. Although it is a simple visualization technique using satellite images, it was able to confirm the possibility of effective monitoring.

정규화 적설지수의 대기보정 영향 분석: 토지피복별 NDSI 변화 및 적설탐지 특성

진동현 ( Donghyun Jin ),안도섭 ( Do-seob Ahn ),김상일 ( Sang-il Kim ) 대한원격탐사학회 2024 대한원격탐사학회지 Vol.40 No.5

The normalized difference snow index (NDSI) is a key indicator used to identify and map snow-covered areas by normalizing the reflectance difference between visible and shortwave infrared bands detected by satellite sensors. This study analyzed the effects of atmospheric correction on NDSI and snow cover detection characteristics according to land cover types. The study used data from the geostationary satellite (GK-2A/AMI) from November 2022 to April 2023. Comparing top-of-atmosphere (TOA) reflectance-based NDSI (NDSITOA) and top-of-canopy (TOC) reflectance-based NDSI (NDSITOC), NDSITOC generally showed higher values. Time series analysis revealed that the difference between the two NDSI values was relatively high when the snow-covered area was extensive. Comparison with S-NPP/VIIRS snow cover showed that NDSITOC-based snow detection had a higher agreement rate than NDSITOA-based snow detection (NDSITOA 72.36%, NDSITOC 75.88%). Analysis by land cover type showed the highest snow cover detection agreement rate in grasslands and croplands, while forest areas showed the lowest agreement rate. These findings emphasize the importance of atmospheric correction in NDSIbased snow cover detection and confirm the need for a customized approach considering land cover characteristics. This study provides a foundation for offering more reliable snow cover information in various fields such as climate change research, water resource management, aviation weather forecasting, and disaster management.