• 한국환경과학회지
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• 제15권12호
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• pp.1087-1091
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• 2006

This paper describes the current spatial patterns of the net primary productivity (NPP) of the terrestrial vegetation and carbon emission (C) in the world due to the burning of fossil fuels in order to clarify the amount of expansion of human activity. The C/NPP value varies spatially from almost zero to several tens of thousand times the local NPP. C/NPP is higher under the condition of extensive human activities due to a high human population density or when the local NPP is extremely low in severe climatic zones. In contrast, the low C/NPP areas are distributed mainly in sparsely populated districts, loading to a low impact of human activity. Although the area where C/NPP is less than 10% accounts for about 70% of the entire land area, one-third of these areas cannot contribute to carbon absorption because of low NPP with a shortage of climatic resources. Since more than half of the areas of the remaining areas are agricultural land and forest ecosystems with high NPP, the possible afforestation area was evaluated to be maximum of $30{\times}10^{6}\;km^{2}$; here only sequestrate carbons that correspond to 2% of the global total NPP are present. These analyses revealed that presently most of the areas where the NPP is high are those exclusively used by humans and that it is difficult for large-scale forest plantations to absorb a substantial amount of the carbon emitted annually by humans.

• 천문학회보
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• 제37권1호
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• pp.85.2-85.2
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• 2012

In this paper, we introduce the 3D modeling of the coronal magnetic field in the solar active region by extrapolating from the 2D observational data numerically. First, we introduce a nonlinear force-free field (NLFFF) extrapolation code based on the MHD-like relaxation method implementing the cleaning a numerical error for Div B proposed by Dedner et al. 2002 and the multi-grid method. We are able to reconstruct the ideal force-free field, which was introduced by Low & Lou (1990), in high accuracy and achieve the faster speed in the high-resolution calculation (512^3 grids). Next we applied our NLFFF extrapolation to the solar active region NOAA 10930. First of all, we compare the 3D NLFFF with the flare ribbons of Ca II images observed by the Solar Optical Telescope (SOT) aboard on the Hinode. As a result, it was found that the location of the two foot-points of the magnetic field lines well correspond to the flare ribbon. The result indicates that the NLFFF well capture the 3D structure of magnetic field in the flaring region. We further report the stability of the magnetic field by estimating the twist value of the field line and finally suggest the flare onset mechanism.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.289-291
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• 2007

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality audio-visual multimedia contents to the uses by the various portable terminals in the mobile environment. Integrated complex reception platform is required to receive multimedia broadcasting services transmitted from various transmission media. In this paper, we present the design and implementation technic for providing the both of terrestrial and satellite DMB services simultaneously using the same hardware platform. The implemented complex receiving terminal to accommodate these DMB services simultaneously need composed of it RF module. it baseband module, it complex control module and the complex de-multiplexer module. The complex control module is designed using uClinux operating system. The complex de-multiplexer, which perform the functions of the address decoder and each DMB stream de-multiplexer, is implemented. with FPGA device. The implemented platform is tested in a real environment and its performance is satisfied with required performance criteria.

• 한국시뮬레이션학회논문지
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• 제15권4호
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• pp.87-96
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• 2006

무선 센서 네트워크는 다양한 분야에서 연구되고 있다. 그 중 해양 센서 네트워크는 해양 환경 감시와 같은 다양한 목적으로 사용 될 수 있다. 그러나 무선 센서 네트워크는 주로 지상에서 연구된다. 기존에 지상에서의 연구는 해양에 적용하기에 부적합하다. 따라서, 해양 환경을 고려한 해양 센서 네트워크 구조를 제안한다. 본 논문에서는 해양 센서 네트워크에 클러스터링 기법과 기능별 노드 구축을 적용하였다. 각 클러스터는 클러스터 데이터를 수집하여 전송한다. 이중의 슈퍼 클러스터 헤드는 각각 수신한 클러스터 데이터를 베이스 스테이션에 전송한다. 제안한 해양 음파 센서 네트워크 라우팅 알고리즘을 구현하고, 테스트 베드를 구축하여 클러스터 데이터의 수신율을 분석한다.

• 방송공학회논문지
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• 제18권4호
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• pp.572-588
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• 2013

본 논문에서는 지상파방송 무선전송 환경에서 4K-UHDTV 혹은 8K-UHDTV 및 UHD-3DTV 등 차세대방송 구현 및 효과적인 수신환경 구축 가능성을 현재 상용화된 전송방식 중 DVB-T2 기술을 중심으로 제안하였다. 특히, 2012년 완료된 지상파방송 디지털전환에 이어 또다시 UHDTV방송을 위한 차세대방송 투자와 전환의 성공조건으로 초고화질 영상 전송 외에도 TV뿐만 아니라 개인형 멀티미디어 단말기에서도 수신이 가능한 직접수신과 실내수신 및 언제 어디서나 자유로운 수신환경 제공도 매우 중요함을 강조하고 있다. 본 논문에서는 UHDTV방송 구현 시 효율적인 주파수 활용과 효과적인 수신환경 구축방안을 찾는데 목적을 두고 있다. 아울러 DVB-T2 전송방식이 가지고 있는 SFN 기능 및 강력한 수신오류정정 능력을 이용하여 VHF대역과 UHF대역 등 2개의 서로 다른 주파수에 의한 SFN 송출망 구성 방법을 제시하고, SFN 소출력중계기 및 가정용 Gap Filler를 활용한 자유로운 무선수신환경 구축 방안을 제안하고 있다. 그 외 10MHz 폭 채널을 이용한 UHDTV방송 효과와 주파수 소요량을 제시한다.

• The Korean Journal of Ecology
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• 제16권1호
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• pp.115-131
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• 1993

Six nutrient cycles involving terrestrial plants are identified and characterized. Plants affect biotic and abiotic cycles through their effects on soil properties. They determine their internal nutritional status and nutrient concentrations in their environment via internal and external cycles. Contributions of organic matter to mycorrhizal, trophic, and detrital mediated external cycles and alterations of nutrient concentrations by plants can promote positive feedbacks leading to increased availability and retention of soil nutrients in open systems. Recognizing alternative cycles through plants leads to a definition of nutrient use efficiency for ecosystems: the ratio of system production to nutrient content of organic matter. A simple graph model to predict changes of nutrient use efficiency during primary succession is then presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2060-2063
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• 2003

Terrestrial DMB(Digital Multimedia Broad-casting) system that is now under standardization in Korea offers multimedia broadcasting services at mobile environment and is based on Eureka-147 DAB(Digital Audio Broadcasting) for transmission method. Also DMB provides the error protection method of convolution coding. In this paper, we study on the effective error resilience coding of MPEG-4 video stream over DMB system. In our algorithm, the first, we partition the MPEG-4 data using the MPEG-4 data partitioning method, and then controls the convolution coding rate according to the importance of the partitioned data. From our simulation result, we show that our algorithm is proper for terrestrial DMB services.

• Environmental Engineering Research
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• 제18권4호
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• pp.259-265
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• 2013

This study was conducted June 2011 at Gamo Lagoon, after tsunami of March 2011, to estimate food sources and utilization. The results show that the tsunami affected the sediment properties by changing the physical environmental alterations. The fatty acids of the gut content of Nuttallia olivacea mostly comprised the same organic matter found in the sediment. Fatty acids in the tissues showed mainly diatoms, bacteria, and dinoflagellates. That is, most of the food sources (i.e., diatoms, bacteria, dinoflagellates, macroalgae, and terrestrial organic matter) probably pass through the digestive system unharmed; however, terrestrial organic matter, which is refractory to biochemical degradation, indicated a different assimilation trend between the gut content and the tissue. This result suggests that input of labile organic matter from the sediment may control selective metabolism in N. olivacea. From these results, although the physical environment of sediment characteristics by tsunami changed, the food utilization of N. olivacea suggested a better assimilation of selected components from the gut content, irrespective of physical alteration.

• ETRI Journal
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• 제28권5호
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• pp.652-655
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• 2006

In this letter, we introduce a new middleware architecture and its generic application programming interface (API) (called the T-DMB MATE API) for terrestrial digital multimedia broadcasting (T-DMB). Middleware in T-DMB enables inter-operable applications to be downloaded from both broadcast and telecommunication networks in advance and to be executed in any type of T-DMB receiver. The middleware we introduce here is especially designed to support a proposed method for application provisions applied to a concept of application module appropriate to the service environment of T-DMB. We also verify the designed T-DMB MATE API through the implementation of the middleware and its application in a PC-based receiver.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.429-430
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• 2006

In this paper, we describe the architecture of interactive data broadcasting server that can transmit the various data-service contents of the Terrestrial DMB(digital multimedia broadcasting). In the broadcasting environment of the Terrestrial DMB, we enjoys the PADS(program associated data service), or the PIDS(program independent data service) to be executed on various T-DMB terminals as well as the basic video or audio services. This server provides the function such as the data contests management, data channel management, service information configure, return channel connection. Etc. Particularly, this system provides the method to create and transfer the application signaling information for the T- DMB middle application based the java language.