• Korean Journal of Medicinal Crop Science
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• v.2 no.3
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• pp.211-218
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• 1994

This experiment was conducted to obtain basic information for the establishment of in vitro initial culture system in Fritillaria thuubergii Miq. Methods of surface sterilization of scale segments as explant and effect of antibiotics added into the culture medium on contamination of explant and chilling treatment of mother bulb on bulblet formation were investigated. Portent of contamination of cultured scale segments was significantly higher in the outer scale segments which were unsuitable as initial culture explant than inner scale segments. Contamination of explants taken from inner scale of bulb was reduced by surface sterilizing explants in the solution of $4{\sim}5%$ sodium hypoclorite for $10{\sim}15$ mimutes. Addition of antibiotics such as kanamycin, vancomycia cefotaxim, agrirnycin and agreptomycin and dithane as fungicide and$lncyte^{tm}$ into MS medium was effective to reduce bateriological contamination, but did not work to control fungi. It had effective to delay the degree of contamination caused by fungi and bacteria haboring in cultured explants. Bulblet formation from cultured scale segments was promoted by dry storage for $2{\sim}4$ weeks or moisture storage of mother bulbs for $4{\sim}6$ weeks at $10^{\circ}C$ before excision of explants. Addition of kinetin into medium could not exerted for the bulblet formation from the scale segment of dry storaged bulb compared to control. But explant taken from 6 week moisture storaged bulb formed more than 10 bulblets per explant on the medium containing $3{\sim}5mg/L$ kinetin.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.5-12
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• 2013

The purpose of this study is to estimate the behavior and the mechanism of debris flow at the end of mountain side when a berm was set on the inclined plane. The numerical model was performed by using the Finite Difference Method(FDM) based on the equation for the mass conservation and momentum conservation. In order to measure the behavior of the debris flow, the debris flow of a straight channel slope and the debris flow of channel slope with 3 types of berms were compared. First, the flow discharge and the sediment volume concentration at the downstream of the channel slope, depending on the various berm width and the different inflow discharges at the upstream of the channel were analyzed. The longer the berm width, the flow discharge at the downstream of the channel was decreased and the high flow fluctuation was reduced by a berm. And it means that a berm can effect for the delay of the debris flow. Through Root Mean Square ratio(RMS) comparison, the flow discharge of the channel slope with a berm was lower than that of a straight channel slope. The longer the berm width, for the sediment volume concentration, an inflection point did not show but mild curve. Because the low sediment concentration with water mixture by a berm continuously flow at the downstream end, it will be effect for reducing the disaster caused by debris flow. The results of this study will provide useful information in predicting and preventing disaster caused by the debris flow.

• Journal of Hospice and Palliative Care
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• v.10 no.1
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• pp.29-34
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• 2007

Purpose: The purpose of this study was to show the differences of medical cost between hospice and non-hospice care for terminally ill patients. This information provides basic data to nationally institutionalize hospice care for decreasing costs and enhancing quality of life for terminally ill patients. Methods: Participants of this study were 114 terminally ill cancer patients who were diagnosed and died with stomach cancer and lung cancer at the K hospital of the C university. The study was a retrospective survey design that analyzed the medical costs for two weeks before they died. The cost analysis was done according to 11 items form the medical cost bill. Results: Patients enrolled in hospice care had significantly lower medical costs (53%) than did non-hospice patients especially in use of TPN, narcotic analgesics, nursing care, radiology tests, and blood tests. Among patients enrolled/admitted in the hospice unit, there was a significant cost difference only in use of analgesics whether the hospice specialized doctor was in charge of care or not. The cost was significantly lower when a hospice specialized doctor was in charge of care although the total medical cost was the same. Conclusion: This study identified lower medical costs for patients cared for in the hospice unit. Thus, we urge institutionalizing hospice care without delay to insure cost benefits as well as quality care.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.11-17
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• 2016

In this paper, we proposed a multi-viewer system with multiple HD cameras based AVB(Audio Video Bridge) ethernet cable using IP networking, and FPGA(Xilinx Zynq 702) for bus safety systems. This AVB (IEEE802.1BA) system can be designed for the low latency based on FPGA, and transmit real-time with HD video and audio signals in a vehicle network. The proposed multi-viewer platform can multiplex H.264 video signals from 4 wide-angle HD cameras with existed ethernet 1Gbps. and 2-wire 100Mbps cables. The design of Zynq 702 based low latency to H.264 AVC CODEC was proposed for the minimization of time-delay in the HD video transmission of car area network, too. And the performance of PSNR(Peak Signal-to-noise-ratio) was analyzed with the reference model JM for encoding and decoding results in H.264 AVC CODEC. These PSNR values can be confirmed according the theoretical and HW result from the signal of H.264 AVC CODEC based on Zynq 702 the multi-viewer with multiple cameras. As a result, proposed AVB multi-viewer platform with multiple cameras can be used for the surveillance of audio and video around a bus for the safety due to the low latency of H.264 AVC CODEC design.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.561-572
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• 2009

In this paper, we propose an efficient layer-separable PES packetization and processing scheme for DVB-S2 satellite broadcasting service based on SVC video. Unlike the conventional single layer-based video coding such as MPEG-2, MPEG-4 and H.264, SVC can combine numerous number of video layers, which are aggregated to a single bitstream. Therefore, it is necessary to devise a new PES packetization scheme that can efficiently separate multiple video layers of SVC. In order to combine the layered characteristics of the SVC video and the robust channel coding capability of LDPC (Low Density Parity Check) of DVB-S2 for unequal error protection, we propose an efficient PES packetization in the transmitter side and PES packet processing scheme in the receiver side of DVB-S2. We prove the effectiveness of the proposed scheme in terms of processing speed and time delay required for processing of the separated layers of SVC video in the satellite broadcasting service.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.293-301
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• 2011

The ionospheric delay is the largest error source in GPS positioning after the SA effect has been turned off in May, 2000. In this study, we used 44 permanent GPS stations being operated by National Geographic Information Institute (NGII) to estimate Total Electron Content (TEC) based on pseudorange measurements phase-leveled by a linear combination with carrier phases. The Differential Code Bias (DCB) of GPS satellites and receivers was estimated and applied for an accurate estimation of the TEC. To validate our estimates of DCB, changes of TEC values after DCB application were investigated. As a result, the RMS error went down by about an order of magnitude; from 35~45 to 3~4 TECU. After the DCB correction, ionospheric TEC maps were produced at a spatial resolution of $1^{\circ}{\times}1^{\circ}$. To analyze the effect of the number of sites used for map generation on the accuracy of TEC values, we tried 10, 20, 30, and 44 stations and the RMS error was computed with the Global Ionosphere Map as the truth. While the RMS error was 5.3 TECU when 10 sites are used, the error reduced to 3.9 TECU for the case of 44 stations.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.209-220
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• 2007

IPS(Intrusion Prevention Systems), which is installed in inline mode in a network, protects network from outside attacks by inspecting the incoming/outgoing packets and sessions, and dropping the packet or closing the sessions if an attack is detected in the packet. In the signature based filtering, the payload of a packet passing through IPS is matched with some attack patterns called signatures and dropped if matched. As the number of signatures increases, the time required for the pattern matching for a packet increases accordingly so that it becomes difficult to develop a high performance US working without packet delay. In this paper, we propose a high performance IPS based on signature hashing to make the pattern matching time independent of the number of signatures. We implemented the proposed scheme in a Linux kernel module in a PC and tested it using worm generator, packet generator and network performance measure instrument called smart bit. Experimental results show that the performance of existing method is degraded as the number of signatures increases whereas the performance of the proposed scheme is not degraded.

• Journal of KIISE
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• v.44 no.1
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• pp.107-113
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• 2017

Real-time multicasting is a packet transmission scheme ensuring that multiple destinations receive a packet within the desired time line. In wireless sensor networks, a packet can be delivered to a limited distance under a given deadline, since the end-to-end delay tends to be proportional to the end-to-end physical distance. Existing real-time multicasting protocols select the distance between the source and the furthest destination as the distance limitation and construct a multicasting tree guaranteeing delivery paths to each destination within the distance limitation. However, the protocols might lead to real-time delivery failures and energy efficiency degradation due to the fixed distance limitation. In this study, we proposed a real-time multicasting protocol using time deadline. The proposed protocol obtains the maximum transmittable distance with a given time deadline and subsequently constructs a multicasting tree using the maximum transmittable distance. The form of the multicasting tree varies according to the given time deadline to trade off the energy efficiency against the real-time delivery success ratio. The simulation results showed that the proposed scheme is superior to the existing protocols in terms of energy efficiency and real-time delivery success ratio under various time deadlines.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.571-580
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• 2005

In fast long-distance networks, TCP's congestion control algorithm has the problem of utilizing bandwidth effectively. Several window-based congestion control protocols for high-speed and large delay networks have been proposed to solve this problem. These protocols deliberate mainly three properties : scalability, TCP-friendliness, and RTT-fairness. These protocols, however, cannot satisfy above three properties at the same time because of the trade-off among them This paper presents a new window-based congestion control algorithm, called EM (Exponential Increase/ Multiplicative Decrease), that simultaneously supports all four properties including fast convergence, which is another important constraint for fast long-distance networks; it can support scalability by increasing congestion window exponentially proportional to the time elapsed since a packet loss; it can support RTT-fairness and TCP-friendliness by considering RTT in its response function; it can support last fair-share convergence by increasing congestion window inversely proportional to the congestion window just before packet loss. We evaluate the performance of EIMD and other algorithms by extensive computer simulations.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.591-602
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• 2003

Delay and discontinuance phenomenon of service are cause by sudden increase of the network communication amount and the quantity consumed of resources when Internet users are driven excessively to a conventional single large database sewer. To solve these problems, spatial database cluster consisted of several single nodes on high-speed network to offer high-performance is risen. But, research about spatial join operation that can reduce the performance of whole system in case process at single node is not achieved. So, in this paper, we propose efficient parallel spatial join processing method in a spatial database cluster system that uses data partitions and replications method that considers the characteristics of space data. Since proposed method does not need the creation step and the assignment step of tasks, and does not occur additional message transmission between cluster nodes that appear in existent parallel spatial join method, it shows performance improvement of 23% than the conventional parallel R-tree spatial join for a shared-nothing architecture about expensive spatial join queries. Also, It can minimize the response time to user because it removes redundant refinement operation at each cluster node.