• ETRI Journal
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• 제36권4호
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• pp.519-527
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• 2014

An integrated multi-beam satellite and multi-cell terrestrial system is an attractive means for highly efficient communication due to the fact that the two components (satellite and terrestrial) make the most of each other's resources. In this paper, a terrestrial component reuses a satellite's resources under the control of the satellite's network management system. This allows the resource allocation for the satellite and terrestrial components to be coordinated to optimize spectral efficiency and increase overall system capacity. In such a system, the satellite resources reused in the terrestrial component may bring about severe interference, which is one of the main factors affecting system capacity. Under this consideration, the objective of this paper is to achieve an optimized resource allocation in both components in such a way as to minimize any resulting inter-component interference. The objective of the proposed scheme is to mitigate this inter-component interference by optimizing the total transmission power - the result of which can lead to an increase in capacity. The simulation results in this paper illustrate that the proposed scheme affords a more energy-efficient system to be implemented, compared to a conventional power management scheme, by allocating the bandwidth uniformly regardless of the amount of interference or traffic demand.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.139-142
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• 1998

This paper presents a method to determine the rolloff factors of both the digital terrestrial TV modulator and the bandpass filter (BPF) at the digital TV receiver input, using an analytical power spectral density model satisfying given co-channel and adjacent channel protection ratios for the digital terrestrial broadcasting services. Since the proposed method is very simple and effective to use, also can be used regardless of type of systems or modulation techniques, this method is expected to be applied to select some other digital terrestrial broadcasting system specifications.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.227-228
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• 2016

Terrestrial laser scanning (TLS) technology is being applied to various fields such as the soil volume calculation and the displacement measurement of terrain, tunnels and dams. This study develops a 3D terrain processing platform for automated earth work using a terrestrial laser scanning data as the software prototype. The developed software provides cells with geo-technical information for planning work to an integrated system.

• 한국콘텐츠학회논문지
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• 제8권12호
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• pp.214-221
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• 2008

지자기는 시간의 경과와 더불어 변동하는데 지자기의 화석이라 할 수 있는 각종 잔류자화를 통해 그 흔적을 남겨두고 있다. 고고지자기 연대법은 소토의 열잔류자화를 통해 과거의 지자기 변동을 측정하여 소토가 출토되는 고고유적의 연대를 알아내는 연대측정법이다. 본고에서는 울산 매곡동 Ⅰ지구 유적의 측구부탄요에서 채취한 14점의 소토시료를 통해 고고유적에 대한 고고지자기 연대법의 적용 방법을 알아보았다. 유물이 출토되지 않아 주변 유구들과의 배치관계 등을 통해 삼국시대라고 추정한 측구부탄요의 불확실한 고고학적 편년에 대해, 고고지자기 연대법에 의해 산출된A.D.440${\pm}$15년의 연대는 확실한 증거자료가 되었다. 고고지자기 연대법은 오염제거가 비교적 용이하고 특히 측정연대의 오차 폭이 상당히 좁아서 신뢰도 높은 결과를 구할 수 있으므로, 고고유적의 연대측정에 있어서 유력한 자연과학적 분석법의 한 분야로 정착되어 가고 있다.

• 디지털융복합연구
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• 제11권6호
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• pp.43-55
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• 2013

본 글은 지상파 방송사의 채널 이미지와 N-스크린 전략 서비스 경영전략 방안을 제안하였다. 이에 방송사의 기존 채널이미지가 다매체, 다채널 서비스로 대변되는 N-스크린 서비스에 미치는 영향을 분석함으로써 향후 지상파 방송사의 N-스크린 운영 방안에 대해서 논의하였다. 현재 지상파 방송 사업자들은 인터넷 기반 동영상 서비스를 제공함으로써 N-스크린 서비스를 실현하고 있다. 고정형 TV- PC-스마트폰-태블릿PC로 연결되는 N-스크린 서비스를 제공하고 있다. 하지만 이용자들이 프로그램을 선택하는 기준은 분석하기 매우 어렵다. 다만, 기존 지상파 방송사의 채널 이미지가 그대로 N-스크린 서비스에 전이되며, 이에 따라 지상파 방송사의 경쟁 도구로 활용된다. 따라서 향후 N-스크린 서비스 제공과 관련된 프로그램 선택 유인, 오리지널 콘텐츠 확보, 새로운 플랫폼 및 서비스 개발 등을 통해서 스마트 미디어 시대를 대비해야 할 것이다.

• 한국위성정보통신학회논문지
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• 제5권2호
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• pp.14-18
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• 2010

미래의 통신망은 지상 네트워크과 위성 네트워크가 결합하거나 협동 통신 하는 방향으로 진화할 것으로 예상된다. 위성/지상 통합 시스템에서 위성과 지상 무선 인터페이스 간 공통성은 단말의 비용을 고려했을 때 매우 중요하게 고려되어야 한다. 특히, 차세대 IMT-Advanced 시스템으로 LTE기반의 지상 시스템이 고려되고 있는 점을 감안했을 때, LTE 기반의 위성 시스템에 대한 연구가 절실히 요구된다. 현존하는 LTE기반의 지상 무선 통신 시스템의 프레임은 최대 100 km 크기의 셀에서 임의 접속이 가능하도록 설계되어 있다. 그러나 위성 시스템의 경우 수 천 km에 이르는 빔 커버리지를 갖기 때문에 최대 100 km의 셀 크기를 고려하여 설계된 LTE프레임 구조 내에서 지상 시스템을 위한 임의 접속 방법을 그대로 적용할 수 없다. 따라서, 본 논문에서는 LTE기반 지상 시스템에서 지원하는 프레임 구조에서 시스템 latency를 줄이고 낮은 복잡도를 가지는 위성 시스템 환경에 적절한 임의 접속 절차를 제안하고자 한다.

• 한국환경과학회지
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• 제27권12호
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• pp.1169-1178
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• 2018

Two man-made carbon emissions, fossil fuel emissions and land use emissions, have been perturbing naturally occurring global carbon cycle. These emitted carbons will eventually be deposited into the atmosphere, the terrestrial biosphere, the soil, and the ocean. In this study, Simple Global Carbon Model (SGCM) was used to simulate global carbon cycle and to estimate global carbon budget. For the model input, fossil fuel emissions and land use emissions were taken from the literature. Unlike fossil fuel use, land use emissions were highly uncertain. Therefore land use emission inputs were adjusted within an uncertainty range suggested in the literature. Simulated atmospheric $CO_2$ concentrations were well fitted to observations with a standard error of 0.06 ppm. Moreover, simulated carbon budgets in the ocean and terrestrial biosphere were shown to be reasonable compared to the literature values, which have considerable uncertainties. Simulation results show that with increasing fossil fuel emissions, the ratios of carbon partitioning to the atmosphere and the terrestrial biosphere have increased from 42% and 24% in the year 1958 to 50% and 30% in the year 2016 respectively, while that to the ocean has decreased from 34% in the year 1958 to 20% in the year 2016. This finding indicates that if the current emission trend continues, the atmospheric carbon partitioning ratio might be continuously increasing and thereby the atmospheric $CO_2$ concentrations might be increasing much faster. Among the total emissions of 399 gigatons of carbon (GtC) from fossil fuel use and land use during the simulation period (between 1960 and 2016), 189 GtC were reallocated to the atmosphere (47%), 107 GtC to the terrestrial biosphere (27%), and 103GtC to the ocean (26%). The net terrestrial biospheric carbon accumulation (terrestrial biospheric allocations minus land use emissions) showed positive 46 GtC. In other words, the terrestrial biosphere has been accumulating carbon, although land use emission has been depleting carbon in the terrestrial biosphere.

• 전자통신동향분석
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• 제38권1호
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• pp.55-64
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• 2023

Recently, preparations for 6G have led to the increasing interest in integrated or hybrid communication networks considering low-orbit satellite communication networks with terrestrial mobile communication networks. In addition, the demand for frequency allocation for new mobile services from low-orbit small satellites to provide global internet of things (IoT) services is increasing. The operation of such satellites and terrestrial mobile communication networks may inevitably cause interference in adjacent bands and the same band frequency between satellites and terrestrial systems. Focusing on the results of the recent ITU-R WP4C meeting, this study introduces the current status of frequency sharing and interference issues between satellites and terrestrial systems, and frequency allocation issues for new mobile satellite operations. Coexistence and compatibility studies with terrestrial IMT in L band and 2.6 GHz band, operated by Inmassat and India, respectively, and a new frequency allocation study (WRC-23 AI 1.18) are carried out to reflect satellite IoT demand. For the L band, technical requirements have been developed for emission from IMT devices at 1,492 MHz to 1,518 MHz to bands above 1,518 MHz. Related studies in the 2 GHz and 2.6 GHz bands are not discussed due to lack of contributions at the recent meeting. In particular, concerning the WRC-23 agenda 1.18 study on the new frequency allocation method of narrowband mobile satellite work in the Region 1 candidate band 2,010 MHz to 2,025 MHz, Region 2 candidate bands 1,695 MHz to 1,710 MHz, 3,300 MHz to 3,315 MHz, and 3,385 MHz to 3,400 MHz, ITU-R results show no new frequency allocation to narrow mobile satellite services. Given the expected various collaborations between satellites and the terrestrial component are in the future, interference issues between terrestrial IMT and mobile satellite services are similarly expected to continuously increase. Therefore, participation in related studies at ITU-R WP4C and active response to protect terrestrial IMT are necessary to protect domestic radio resources and secure additional frequencies reflecting satellite service use plans.

• 조명전기설비학회논문지
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• 제24권4호
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• pp.57-65
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• 2010

본 논문에서는 한국 지형에 적합한 지상파 ATSC DTV용 채널 모델을 제시하였다. 이를 위해 지상파 DTV 방송과 관련된 기존 전파 모델을 연구하고, 한국방송공사에서 실시한 지상파 DTV 방송 필드테스트의 실측 데이터를 분석하였다. 실제 측정한 전계강도를 기반으로 제시한 채널 모델은 기존의 전파모델에 비해 더 정확한 값을 가진다. 제시한 채널 모델은 지상파 DTV 시스템 실행시 요구되는 link budget 계산에 유용할 것이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.567-569
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• 2006

Recently, the terrestrial laser scanner is considered as useful measurement equipment for acquiring a three-dimensional data. In this study, a terrestrial laser scanner which has +/- 2.5cm accuracy is examined whether the terrestrial laser scanner is reliable to present the tendency of landslide movement. The test area is covered by protection blocks, and they are being moved by landslide movement. Landslide movement was detected by measuring the movement of protection blocks. Totally three scenes of test area were acquired during 2004 and 2006. The three scenes of the protection blocks were registered in global coordinate system, then the landslide movement was investigated. The landslide movement detected in the three scenes was evaluated by comparing with landslide movement measured by a total station. Although the measurement accuracy of landslide using the terrestrial laser scanner was worse than the total station, the scanning data showed the tendency of landslide movement of the test area.