• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1141-1153
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• 2010

This paper introduces ONLIS(Overlay Multicast Network for Live IPTV Service), a novel overlay multicast network optimized to deliver live broadcast IPTV stream. We analyzed IPTV reference model of ITU-T IPTV standardization group in terms of network and stream delivery from the source networks to the customer networks. Based on the analysis, we divide IPTV reference model into 3 networks; source network, core network and access network, ION(Infrastructure-based Overlay Multicast Network) is employed for the source and core networks and PON(P2P-based Overlay Multicast Network) is applied to the access networks. ION provides an efficient, reliable and stable stream distribution with very negligible delay while PON provides bandwidth efficient and cost effective streaming with a little tolerable delay. The most important challenge in live P2P streaming is to reduce end-to-end delay without sacrificing stream quality. Actually, there is always a trade-off between delay & stream quality in conventional live P2P streaming system. To solve this problem, we propose two approaches. Firstly, we propose DSPT(Distributed Streaming P2P Tree) which takes advantage of combinational overlay multicasting. In DSPT, a peer doesn't fully rely on SP(Supplying Peer) to get the live stream, but it cooperates with its local ANR(Access Network Relay) to reduce delay and improve stream quality. When RP detects bandwidth drop in SP, it immediately switches the connection from SP to ANR and continues to receive stream without any packet loss. DSPT uses distributed P2P streaming technique to let the peer share the stream to the extent of its available bandwidth. This means, if RP can't receive the whole stream from SP due to lack of SP's uploading bandwidth, then it receives only partial stream from SP and the rest from the ANR. The proposed distributed P2P streaming improves P2P networking efficiency.

• The Korean Journal of Financial Management
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• v.25 no.1
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• pp.1-22
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• 2008

This study is to evaluate, to the extent to, which advanced currency futures and emerging currency futures markets can predict accurately the future spot rate. To this end, Johansen's the maximum-likelihood cointegration method(1988, 1991) is adopted to test the unbiasedness and efficiency hypothesis. Also, this study is to estimate and compare a quantitative measure of relative efficiency as a ratio of the forecast error variance from the best-fitting quasi-error correction model to the forecast error variance of the futures price as predictor of the spot price in advanced currency futures with in emerging currency futures market. Advanced currency futures is British pound and Japan yen. Emerging currency futures includes Korea won, Mexico peso, and Brazil real. The empirical results are summarized as follows : First, the unbiasedness hypothesis is not rejected for Korea won and Japan yen futures exchange rates. This indicates that the emerging currency Korea won and the advanced currency Japan yen futures exchange rates are likely to predict accurately realized spot exchange rate at a maturity date without the trader having to pay a risk premium for the privilege of trading the contract. Second, in emerging currency futures markets, the unbiasedness hypothesis is not rejected for Korea won futures market apart from Mexico peso and Brazil real futures markets. This indicates that in emerging currency futures markets, Korea won futures market is more efficient than Mexico peso and Brazil real futures markets and is likely to predict accurately realized spot exchange rate at a maturity date without risk premium. Third, this findings show that the results of unbiasedness hypothesis tests can provide conflicting finding. according to currency futures class and forecasts horizon period, Fourth, from the best-fitting quasi-error correction model with forecast horizons of 14 days, the findings suggest the Japan yen futures market is 27.06% efficient, the British pound futures market is 26.87% efficient, the Korea won futures market is 20.77% efficient, the Mexico peso futures market is 11.55%, and the Brazil real futures market is 4.45% efficient in the usual order. This indicates that the Korea won-dollar futures market is more efficient than Mexico peso, and Brazil real futures market. It is therefore possible to concludes that the Korea won-dollar currency futures market has relatively high efficiency comparing with Mexico peso and Brazil real futures markets of emerging currency futures markets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.543-549
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• 1997

The problems in the existing modeling rules for fishing nets, especially in the Tauti's rule which had been used most commonly, were investigated and it was found that the rules could not give a good similarity between the prototype and model nets because they din neither analyze the flow resistance of nets accurately nor decide the ratio of flow velocity between the two nets properly. Thus, the modeling rule was newly derived by regarding the nets as holey structures sucking water into their mouth and then filtering water through their meshes as in the previous paper. The similarity conditions obtained, between the two nets distinguished by subscript 1 and 2, are as follows; $$\frac{d_2}{d_1}=\sqrt{\frac{l_2}{l_1}},\;\frac{N_2}{N_1}=(\frac{d_1}{d_2})^{1.5}\frac{L_2}{L_1},\;\varphi_1=\varphi_2,\;\frac{d_{r2}}{d_{r1}}=\sqrt{\frac{L_2{(\rho_{r1}-\rho_{w1})}}{{L_1{(\rho_{r2}-\rho_{w2})}}$$ $$\frac{N_{a2}}{N_{a1}}=\frac{W_{a1}}{W_{a2}}(\frac{L_2}{L_1})^2,\;\nu_1=\nu_2\;and\;\frac{R_2}{R_1}=(\frac{L_2}{L_1})^2$$, where L is the length of nettings, d the diameter of netting twines, 2l the mesh size, $2\varphi$ the angle between two adjacent bars, N the number of meshes at the sides of nettings, $d_r$, the diameter of ropes, $\rho_r$, the specific gravity of ropes, $W_a$ the weight in water of one piece of float or sinker, $N_a$ the number of floats or sinkers, $\nu$ the flow velocity, and R the flow resistance of net. In the case where the model experiments aim at investigating the influence of weight in water of nettings on their shapes in nets subjected to the water flow of very low velocity, however, the following condition is added; $$\frac{\rho_2-\rho_{w2}}{\rho_1-\rho_{w1}}=\frac{d_1}{d_2}$$ where $\rho$ is the specific gravity of netting twines.

• Tunnel and Underground Space
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• v.28 no.5
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• pp.400-425
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• 2018

This study presents the research results and current status of the DECOVALEX-2019 project Task B. Task B named 'Fault slip modelling' is aiming at developing a numerical method to simulate the coupled hydro-mechanical behavior of fault, including slip or reactivation, induced by water injection. The first research step of Task B is a benchmark simulation which is designed for the modelling teams to familiarize themselves with the problem and to set up their own codes to reproduce the hydro-mechanical coupling between the fault hydraulic transmissivity and the mechanically-induced displacement. We reproduced the coupled hydro-mechanical process of fault slip using TOUGH-FLAC simulator. The fluid flow along a fault was modelled with solid elements and governed by Darcy's law with the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by creating interface elements between two separating rock blocks in FLAC3D. A methodology to formulate the hydro-mechanical coupling relations of two different hydraulic aperture models and link the solid element of TOUGH2 and the interface element of FLAC3D was suggested. In addition, we developed a coupling module to update the changes in geometric features (mesh) and hydrological properties of fault caused by water injection at every calculation step for TOUGH-FLAC simulator. Then, the transient responses of the fault, including elastic deformation, reactivation, progressive evolutions of pathway, pressure distribution and water injection rate, to stepwise pressurization were examined during the simulations. The results of the simulations suggest that the developed model can provide a reasonable prediction of the hydro-mechanical behavior related to fault reactivation. The numerical model will be enhanced by continuing collaboration and interaction with other research teams of DECOLVAEX-2019 Task B and validated using the field data from fault activation experiments in a further study.

• Progress in Medical Physics
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• v.23 no.3
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• pp.188-198
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• 2012

This study aims to evaluate the accuracy of the collapsed cone convolution (CCC) algorithm for dose calculation in a treatment planning system (TPS), CorePLAN$^{TM}$. We implemented beam models for various setup conditions in TPS and calculated radiation dose using CCC algorithm for 6 MV and 15 MV photon beam in $50{\times}50{\times}50cm^3$ water phantom. Field sizes were $4{\times}4cm^2$, $6{\times}6cm^2$, $10{\times}10cm^2$, $20{\times}20cm^2$, $30{\times}30cm^2$ and $40{\times}40cm^2$ and each case was classified as open beam cases and wedged beam cases, respectively. Generated beam models were evaluated by comparing calculated data and measured data of percent depth dose (PDD) and lateral profile. As a result, PDD showed good agreement within approximately 2% in open beam cases and 3% in wedged beam cases except for build-up region and lateral profile also correspond within approximately 1% in field and 4% in penumbra region. On the other hand, the discrepancies were found approximately 4% in wedged beam cases. This study has demonstrated the accuracy of beam model-based CCC algorithm in CorePLAN$^{TM}$ and the most of results from this study were acceptable according to international standards. Although, the area with large dose difference shown in this study was not significant region in clinical field, the result of our study would open the possibility to apply CorePLAN$^{TM}$ into clinical field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.320-328
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• 1992

The soybean yield forcasting models based on climatic elements in six locations were estimated by the STEPWISE/MAXR, Cp statistics and GLM procedure of SAS. The climatic elements were aerial temperature, sunshine hours and precipitation from May to October in 20 years. The investigated six locations were Chunchon, Suwon, Cheongju, Kwangju, Iri and Jinju. The important climatic elements for main effects in Chunchon model were August sunshine hours-linear term, August precipitation-quadratic. June temperature to August precipitation and May temperature to August precipitation were interaction terms. The quadratic August precipitation was assumed to be related to yield in Chunchon. The main effects of Suwon were linear-June temperature, quadratic June sunshine hours and June precipitation. These terms affected yields negatively. The main effects of Cheongju were linear June temperature and quadratic August precipitation. May temperature to June precipitation, July to August precipitations were interactions. The main effects of Kwangju were linear July precipitation, quadratic June temperature and July precipitation. June to July sunshine hours of interaction terms influenced yield negatively. The main effects of Iri were linear May sunshine hours, quadratic May and July sunshine hours. May temperature to May precipitation and June to July precipitations affected yields negatively. The main effects of Jinju were linear June and August precipitations. August temperature to August sunshine hours, June sunshine hours to July precipitation and June to August precipitation were interactions. In linear terms, June and August precipitations and, in interactions, August to August sunshine hours were negative efficacies respectively. The included year variables in Chunchon, Suwon, Kwangju, and Jinju model building were recognized as a linear trend based on an assumption that the technological factors have improved through times.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.28-34
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• 2015

This study is to investigate microbiological hazards which can be used as fundamental data to adequately control leeks hazards and develop leeks GAP model for those who want to get GAP system. The microbiological investigations on cultivation environments (soil and water), crops (leeks), personal hygiene (workers' hands, clothes and gloves) and working tools (boxes) have been conducted for one year, so the period was classified under non-cultivation, cultivation, and post harvest. Total bacteria was detected from soil (4.0~6.7 log CFU/g), leeks (4.6~5.1 log CFU/g), hands (ND~3.3 log CFU/hand) and gloves ($ND{\sim}5.4\;log\;CFU/cm^2$) while nothing was detected from the other samples. The coliform contamination of leeks (4.8~5.0 log CFU/g) was more high than that of soil (3.9~4.2 log CFU/g). In case of foodborne pathogens, only B. cereus was detected at the level of 0.5~4.6 log CFU/g (or hand, $100cm^2$). Fungi was observed at the level of 2.1~3.8 log CFU/g (or hand, $100cm^2$) excepting water and some working tools. These results demonstrate that the contamination of leeks is comparatively higher than that of soil sample. The reason may be the cross-contamination by biological hazards presenting on soil. Therefore, it is necessary to properly control soil and fertilizer for safety against biological hazards.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.371-379
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• 2012

This study was designed to explore new nutraceutical and cosmetic resources possessing biological activities from the plant kingdom. To fulfill this purpose, we analyzed the anti-oxidative, anti-melanogenic, and anti-inflammatory activities of Zanthoxylum schinifolium extract (ZSE) and its solvent fractions using in vitro assays and cell culture model systems. Three kinds of ZSE treated with methanol, ethanol, and water exhibited potent anti-oxidative activities through DPPH radical scavenging capacity, and inhibited in vitro DOPA oxidation. Furthermore, Z. schinifolium methanol extract (ZSME) inhibited the ${\alpha}$-melanocyte stimulating hormone, which induces melanin contents in B16F10 cells. Its anti-melanogenic activity originates from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Moreover, lipopolysaccharide induced nitric oxide production in the RAW 264.7 cell line was also ameliorated by ZSME treatment in a dose dependent manner. Among the four solvent fractions of ZSME treated with dichloromethane, ethyl acetate, n-butanol, and water, three fractions, except water, showed significant anti-melanogenic and anti-inflammatory activities. Taken together, these results provide important new insights into Z. schinifolium, indicating that it possesses numerous biological activities such as anti-oxidative, anti-melanogenic, and anti-inflammatory activities. Therefore, it may well serve as a promising material in the field of nutraceuticals and cosmetics.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.432-442
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• 2009

This research had a look at what effect of the pursing benefit has on satisfaction, behavioral intention, and attitude of the visitors to the Gwangju Biennale. The survey was conducted for 320 visitors who finished their exhibition viewing schedule starting September 5 until September 19 [15 days]. 300 questionnaires excepting 20 unfaithfully responded copies among those collected from the surveyed were used for the analysis. As for the statistical disposal of the collected data, after going through the process of Data Coding, this research conducted an frequency analysis using SPSS 12.0 for window & statistics package program AMOS 5.0, an exploratory factor analysis to test the reliability and feasibility of the data, and reliability test of each factor; then, this research tested a hypothesis using structural equation model. The research results are as follows: First, as a result of factor analysis of the 15 pursuing benefits, 4 factors were elicited, such as pursuit of an intellectual experience, pursuit of a novel, exotic experience, pursuit of interpersonal, cultural exchange, and pursuit of internal fullness, etc.; as a result of factor analysis of the 10 attitudes, three factors were elicited, such as affective, cognitive, behavioral factors; as a result of factor analysis of 12 types of satisfaction, two factors, such as satisfaction with facilities and convenience matters, etc. were elicited. Second, as a result of the suitability of research model, suitability, its fidelity came out as $x^2=107.508$, d.f.=48, p=.000, Q=2.240, GFI=.942, AGFI=.906, RMR=.024, NFI=.952, TLI=.963, CFI=.973, RMSEA=.064. Third, pursuing benefit was found out to have a positive effect on satisfaction, attitude, and behavioral intention. Fourth, attitude was found out to have a positive significant effect on satisfaction. Fifth, attitude was found out to have a positive effect on behavioral intention. Sixth, satisfaction was found out to have a positive effect on behavioral intention.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.275-282
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• 2018

Miscanthus species are known as a genus of eco-friendly and low-maintenance cost ornamental grasses. Plug and cutting methods were tested for multi-propagation of most promising ornamental Miscanthus species in greenhouse and field plot. The plug formation period with three different cell sizes with four cultivars (M. sinensis 'Andersson', 'Strictus', 'Gracillimus', 'Variegatus') were evaluated the seedling development stages with two irrigation types of the over-head and the bottom watering in greenhouse and field plot afterward during 2015-2016 season. In seedling plug test, the size of tray cell affected the plug formation. Bottom irrigation resulted positively on plant height, weight, root and tiller development compared with the over-head irrigation. Plug cell size affected the plant growth in the field after transplanting. All of the 3 Miscanthus species showed higher rates of successful propagation at the lower nodes before inflorescence formation (vegetative growth stage). To analyze the survival factors of M. xgiganteus cutting, the cutting time, node part, and culm diameter were tested as independent variables with the binary logistic model. The survival probability was influenced by node part and culm diameter significantly. The third and fifth node parts showed 0.12 (8X higher failure probability) and 0.02 (50X higher failure probability) times less survival probability. It means the survival probability will be increased by using older and lower part of cuttings during a vegetative growth stage before inflorescences of M. xgiganteus.