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단일 모드 광섬유와 다중 모드 광섬유 혼합 라인으로 구성된 FTTx 시스템의 전송 성능 평가
박승현,김경헌,이일항,Park, Seung-Hyeon,Kim, Kyong-Hon,Lee, El-Hang 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.7a
본 논문은 채널을 파장별로 할당하는 방식인 WDM-PON을 각각의 채널당 단일광원을 사용하는 방식을 이용하여 기가비트 전송이 가능한 GPON 표준에 맞춰 단일 모드 광섬유와 다중 모드 광섬유로 혼합 구성된 망을 제안하고, 제안된 시스템의 전송 특성을 실험을 통해 고찰하였다. 본 시스템은 고속의 하향전송을 위해 직접변조가 가능한 DFB-LD를 사용하였고, 상향전송을 위해서는 저가의 ONU구성을 위해 SFP 타입의 Transceiver모듈을 사용하였다. 광 선로구간에서의 파장다중화를 위해서 채널 결합 및 분기기능을 갖는 MUX/DEMUX를 이용하였으며, SMF로 이루어진 WDM-PON망의 ONU단에 추가로 1km이내의 MMF를 연결시켜 두 라인을 혼합시킨 시스템을 구성하였다. 시스템의 타당성을 입증하기 위해 ITU-T G.984.2에서 권고하는 하향 2.5 Gbit/s, 1.25 Gbit/s, 상향 1.25 Gbit/s, 622 Mbit/s 속도의 전송실험을 하였으며, 표준안을 근거로 비교분석하여 상$\cdot$하향 전송에서 적합성과 여유도를 확인하였다. This paper proposes a hybrid optical lines composed of single-mode fiber(SMF) and multi-mode fiber(MMF) for gigabit-capable Passive Optical Network(GPON) using a WDM method with a single light source per each channel, and reports the results of transmission performance the proposed lines. The transmission link uses a direct modulated DFB-LD for high speed downstreams at the optical line terminal(OLT) of central office(CO) and a low cost SFP type transceiver for low-speed upstream in optical network unit(ONU). To split or combine the transmission channels, wavelength MUX/DEMUX are used in the optical line section, and MMFs not longer than 1 km are attached to the SMF lines at the ONU side of the WDM-PON links. We have performed the transmission experiment on the downstream of 2.5 Gbit/s, and 1.25 Gbit/s, and the upstream of 1.25 Gbit/s, and 622 Mbit/s which are recommended by ITU-T G.984.2. The transmission margin and feasibility of the proposed links have been tested to be suitable up to 2.5 Gbit/s transmission.
박승현,Park Seung Hyun 한국아동간호학회 1996 Child Health Nursing Research Vol.2 No.2
The purpose of this study is to explore the level of children's anxiety related to disease characteristics The subjects of this study were 72 childrens (6year-10 year) who were admitted to the pediatric wards at University Hospital and 24 healthy children, and 24 mothers of children with fatal & chronic illness. The data were collected with sarason's Anxiety scale for children & spielberger's State Trait Anxiety Inventory for mothers and analyzed of One way Anova, Duncun Test, Pearson correlation, and T-test. The results of this study were as follows : 1) There was significant difference in children's anxiety related to disease characteristics(P<0.01) Fatally ill children showed highest level of anxiety and chronically, acutely ill children in order. And there was no significant difference in anxiety between acutely ill children and healthy children. There was significant difference in anxiety between groups of ill and healthy children(P<0.01) .The anxiety of ill children was higher than that of healthy children. 2) There was no significant correlation between children's anxiety and their age. 3) There was no significant difference in children's anxiety related to frequency of hospital admission. 4) There was significant correlation between children's anxiety and duration of illness(P<0.01). The longer the duration of illness is, the higher children's anxiety is. 5) There was significant difference in mothers' anxiety between groups of fatally ill and chronically ill children(P<0.05). The anxiety of mothers of fatally ill children was higher than that of mothers of chronically ill children. 6) There was no significant correlation between children's anxiety of fatal and chronic illness and their mothers' anxiety.
A Parallel Processing Technique for Large Spatial Data
박승현,오병우 대한공간정보학회 2015 Spatial Information Research Vol.23 No.2
Graphical processing unit (GPU) contains many arithmetic logic units (ALUs). Because many ALUs can be exploited to process parallel processing, GPU provides efficient data processing. The spatial data require many geographic coordinates to represent the shape of them in a map. The coordinates are usually stored as geodetic longitude and latitude. To display a map in 2-dimensional Cartesian coordinate system, the geodetic longitude and latitude should be converted to the Universal Transverse Mercator (UTM) coordinate system. The conversion to the other coordinate system and the rendering process to represent the converted coordinates to screen use complex floating-point computations. In this paper, we propose a parallel processing technique that processes the conversion and the rendering using the GPU to improve the performance. Large spatial data is stored in the disk on files. To process the large amount of spatial data efficiently, we propose a technique that merges the spatial data files to a large file and access the file with the method of memory mapped file. We implement the proposed technique and perform the experiment with the 747,302,971 points of the TIGER/Line spatial data. The result of the experiment is that the conversion time for the coordinate systems with the GPU is 30.16 times faster than the CPU only method and the rendering time is 80.40 times faster than the CPU.