• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.758-765
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• 2007

In this paper, we propose an efficient seamless handoff scheme to minimize packet loss and unnecessary packets on the Internet using the peculiar mobility characteristics of public vehicles such as trains. MR (Mobile Router) in a train visits each AR (Access Router) in the fixed order. As the MR detects reachability to the NAR (Next Access Router) on the new link, the PAR (Previous Access Router) can directly deliver packets from MR's HA (Home Agent) to the NAR according to the HML (Handoff Mobile router List). Then. the NAR buffers them until the MR finishes L3 (Layer 3) handoff procedure with the NAR. Therefore, our scheme can support a seamless handoff without the packet loss and unnecessary packets on the Internet. The result of our performance evaluation has shown that the proposed scheme could provide excellent performance, compared with the NEMO basic support protocol and the Bi-casting protocol.

• Water for future
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• v.29 no.6
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• pp.167-178
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• 1996

The simulation techniques of hydrologic data series have been developed for the purposes of the design of water resources system, the optimization of reservoir operation, and the design of flood control of reservoir, etx. While the stochastic models are usually used in most analysis of water resources fields for the generation of data sequences, the indexed sequential modeling (ISM) method based on generation of a series of overlapping short-term flow sequences directly from the historical record has been used for the data generation in western USA since the early of 1980's. It was reported that the reliable results by ISM were obtained in practical applications. In this study, we generate annual inflow series at a location of Hong Cheon Dam site by using ISM method and first order autoregressive model (AR(1)), and estimate the drought characteristics for the comparison aim between ISM and AR(1).

• Membrane Journal
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• v.11 no.1
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• pp.38-49
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• 2001

The surface of polyimide membrane was modified by plasma treatment using Ar and NH~. and the permeability and selectivity for the mixture gas $(CO_2/N_2=20/80 vol%)$ were measured. The per¬meation experiments were performed by a variable volume method at $30^{\circ}$C and total pressure of 5 atm, The effect of the plasma conditions such as treatment time, power input, gas flow rate and pressure in the reactor on the transport Dwperties of modified membranes was investigated. The surface of the plasma treated membrane was analyzed by means of FTlR - ATH, ESCA and AFM. The dependences of the wettability and the etching on plasma treatment time were investigated by use of the contact angle and the weight loss measurement. Measurements of gas pcnneability characteristic were performed using both dry and wet membranes. The effects of experimental conditions such as temperature on the membrane performance were studied.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.701-710
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• 2016

The purpose of this paper is to build a model of packet amount of Naver mobile portal. We collected 2004 cases by measuring the sixth per access from September, 2012 to October, 2015. We use regression model with autoregressive errors, in which predictors incorporated into the model were replication, date, time, week, month. It has been found the model which errors follow AR(36), based on AIC and adjusted $R^2$. We found some characteristics from our model as follows. In addition to model building, we also have discussed some meaningful features yielded from the selected model in this paper. Considering the importance of this topic, continuous researches are needed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.1
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• pp.21-26
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• 2004

Results from PL and Raman spectroscopic analyses of HPHT (high-pressure high-temperature) treated type IIa diamonds are presented, and these spectral characteristics are compared with those of untreated diamonds of similar color and type. We identify a number of significant changes by 325 nm He/Cd laser excitation. Several peaks are removed completely, including H4, H3 system in HPHT treated diamond. The N3 system, however, increased in emission. Also we can find the behaviour of the nitrogen-vacancy related center N-V centers at 575 and 637.1 nm, as observed with 514 nm Ar ion laser excitation. When these centers are present, the FWHM (full width at half maximum) of 637.1 nm luminescence intensities offers a potential means of separating HPHT-treated from untreated type IIa diamonds. The width of 637.1 nm $(N-V)^-$line measured at the position oi half the peak's height are determine to range from 19.8 to $32.1cm^{-1}$ for HPHT treated diamonds.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.4
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• pp.1-6
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• 2000

Recently, SrBi$_{2}$Ta$_{2}$ $O_{9}$(SBT) and Pb(Zr,Ti) $O_{3}$(PZT) were much attracted as materials of capacitor for ferroelectric random access memory(FRAM) with higher read/ write speed, lower power consumption and nonvolartility. SBT thin film has appeared as the most prominent fatigue free and low operation voltage. To highly integrate FRAM, SBT thin film has to be etched. A lot of papers have been reported over growth of SBT thin film and its characteristics. However, there are few reports about etching SBT thin film owing to difficult of etching ferroelectric materials. SBT thin film was etched in CF$_{4}$Ar plasma using magnetically enhanced inductively coupled plasma (MEICP) system. In order to investigate the chemical reaction on the etched surface of SBT thin films, X-ray Photoelecton spectrosocpy (XPS) and Secondary ion mass spectroscopy(SIMS) was performed.

• Journal of the Korean Vacuum Society
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• v.12 no.2
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• pp.112-117
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• 2003

MgO films is widely used in plasma display panel (PDP) technology. In this work, structural and optical properties of the MgO films deposited by e-beam evaporation, reactive magnetron sputtering, which are commercially used, and arc deposition were compared. MgO thin films were deposited on glass substrates by vacuum arc deposition equipment using a magnesium metal target at various oxygen gas flows. In order to investigate the packing density by ellipsometer, to measure reasonable erosion-rates of the MgO protective layers, we introduced an acceleration test method, namely, Ar+ ion beam induced erosion test. Also, XPS and UV test were adopted to examine the effect of the moisture on the optical transmittance of the MgO protective layers, which showed that these of MgO films by arc deposition method sustained more 90% and were insensitive to effect of the moisture. XRD and AFM have been also used to study behaviors of the structure and surface morphology.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.210-210
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• 2011

The effects of CH2F2 and N2 gas flow rates on the etch selectivity of silicon nitride (Si3N4) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si3N4 pattern were investigated during etching of a Si3N4/EUV resist structure in dual-frequency superimposed CH2F2/N2/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH2F2 and N2 gases played a critical role in determining the process window for ultra-high etch selectivity of Si3N4/EUV resist due to disproportionate changes in the degree of polymerization on the Si3N4 and EUV resist surfaces. Increasing the CH2F2 flow rate resulted in a smaller steady state CHxFy thickness on the Si3N4 and, in turn, enhanced the Si3N4 etch rate due to enhanced SiF4 formation, while a CHxFy layer was deposited on the EUV resist surface protecting the resist under certain N2 flow conditions. The LER values of the etched resist tended to increase at higher CH2F2 flow rates compared to the lower CH2F2 flow rates that resulted from the increased degree of polymerization.

• Journal of Sensor Science and Technology
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• v.4 no.3
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• pp.37-42
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• 1995

The PLT thin films on MgO substrate have been fabricated by RF magnetron sputtering and the dependence of properties on fabrication conditions have been studied. The PbO-rich target was used and the optimum fabrication conditions of the PLT thin films were such that substrate temperature, working pressure, $Ar/O_{2}$ ratio, and rf power was $640^{\circ}C$, 10 mTorr, 10:1, and $1.7\;W/cm^{2}$, repectively. In these conditions, the PLT thin film showed the deposition rate of $62.5\;{\AA}/min$, the Pb/Ti ratio of 1/2, and the dielectric constant of 200. The PLT thin film showed good c-axis orientation and crystalinity according to XRD and SEM analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.442-443
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• 2006

Electrical, optical, surface, and structural properties of amorphous indium zinc oxide (IZO) films grown on $SiO_2$/PES/$SiO_2$ substrate by a RF sputtering in pure Ar ambient at room temperature were investigated. A sheet resistance of $13.5\;{\Omega}{\square}$, average transmittance above 85 % in 550 nm, and root mean square roughness of $10.5\;{\AA}$ were obtained even in the IZO layers grown at room temperature in pure Ar ambient. Without addition of oxygen gas during IZO sputtering process, we can obtain high quality IZO anode films from the specially synthesized oxygen rich IZO target. XRD result shows that the IZO films grown at room temperature is completely amorphous structure due to low substrate temperature. In addition, the electrical and optical properties of the flexible OLED fabricated on IZO/$SiO_2$/PES/$SiO_2$ is critically influenced by the electrical properties of a IZO anode. This findings indicate that the IZO/$SiO_2$/PES/$SiO_2$ is a promising anode/substrate scheme for realizing organic based flexible displays.