• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.2 s.17
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• pp.9-16
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• 2005

This paper presents the use of an Artificial Neural Network (ANN) as a viable means of forecasting Inundation Damage Area (IDA) in many watersheds. In order to develop the forecasting model with various environmental factors, we selected 108 watershed areas in South Korea and collected 49 damage data sets from 1990 to 2000, of which each set is composed of 27 parameters including the IDA, rainfall amount, and land use. After successful training processes of the ANN, a good agreement (R=0.92) is obtained (under present conditions) between the measured values of the IDA and those predicted by the developed ANN using the remaining 26 data sets as input parameters. The results indicate that the inundation damage is affected by not only meteorological information such as the rainfall amount, but also various environmental characteristics of the watersheds. So, the ANN proves its present ability to predict the IDA caused by an event of complex factors in a specific watershed area using accumulated temporal-spatial information, and it also shows a potential capability to handle complex non-linear dynamic phenomena of environmental changes. In this light, the ANN can be further harnessed to estimate the importance of certain input parameters to an output (e.g., the IDA in this study), quantify the significance of parameters involved in pre-existing models, and contribute to the presumption, selection, and calibration of input parameters of conventional models.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.32-39
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• 2009

Semantically-operated services, which is different from Web services or semantic Web services with semantic markup, can be defined as the services providing search function or reasoning function using ontologies. It performs a pre-defined task by exploiting URI, ontology classes, and ontology properties. This study introduces a method for pipelining semantically-operated services based on a semantic broker which refers to ontologies and service description stored in a service manager and invokes by user constraints. The constraints consist of input instances, an output class, a visualization type, service names, and properties. This method provides automatically-generated service pipelines including composit services and a simple workflow to the user. The pipelines provided by the semantic broker can be executed in a fully-automatic manner to find a set of meaningful semantic pipelines. After all, this study would epochally contribute to develop a portal service by ways of supporting human service planners who want to find specific composit services pipelined from distributed semantically-operated services.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.49-60
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• 2017

In this paper, we presented the result of the study on high-power handling capability of the X-band circular waveguide cavity filter configured at the output of high power amplifier(120 W) for geostationary satellites. The dual mode circular waveguide cavity filter with 6th order is selected and the physical model of the filter is designed after determination of the size of resonator from mode chart. Multipactor margin analysis is performed by the SEM method and the VMF method. The result shows that the VMF method predicts lower multipactor breakdown thresholds than the SEM method. Evaluating the multipactor margin obtained by the VMF method to ECSS criteria, we could decide to perform multipactor test. The multipactor test conducted in ESA facility shows that multipactor did not occur even until the RF power increased up to 540 W. In consequence, by both analysis and test, we could verify that the X-band circular waveguide cavity filter has the sufficient high-power handling capability to operate on orbit.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.9-15
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• 2007

Thermoelectric properties of the electrodeposited Bi-Te films and photoresist process have been investigated to apply for thermoelectric thin film devices. After plating in Bi-Te solutions of 20 mM concentration, which were prepared by dissolving $Bi_2O_3$ and $TeO_2$ into 1M $HNO_3$, thermoelectric properties of the films were characterized with variation of the Te/(Bi+Te) ratio in a plating solution. With increasing the Te/(Bi+Te) ratio in the plating solution from 0.5 to 0.65, Seebeck coefficient of Bi-Te films changed from $-59{\mu}V/K$ to $-48{\mu}V/K$ and electrical resistivity was lowered from $1m{\Omega}-cm$ to $0.8m{\Omega}-cm$ due to the increase in the electron concentration. Maximum power factor of $3.5{\times}10^{-4}W/K^2-m$ was obtained for the Bi-Te film with the $Bi_2Te_3$ stoichiometric composition. Using multilayer overhang process, the photoresist pattern to form thermoelectric legs of 30 m depth and 100m diameter was successfully fabricated fur micro thermoelectric device applications.

• Geophysics and Geophysical Exploration
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• v.19 no.1
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• pp.11-19
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• 2016

Two representative residual static methods of traveltime decomposition and stack-power maximization are discussed in terms of application to land seismic data. For the model data with synthetic shot/receiver statics (time shift) applied and random noises added, continuities of reflection event are much improved by stack-power maximization method, resulting the derived time-shifts approximately equal to the synthetic statics. Optimal parameters (maximum allowable shift, correlation window, iteration number) for residual statics are effectively chosen with diagnostic displays of CSP (common shot point) stack and CRP (common receiver point) stack as well as CMP gather. In addition to removal of long-wavelength time shift by refraction statics, prior to residual statics, processing steps of f-k filter, predictive deconvolution and time variant spectral whitening are employed to attenuate noises and thereby to minimize the error during the correlation process. The reflectors including horizontal layer of reservoir are more clearly shown in the variable-density section through repicking the velocities after residual statics and inverse NMO correction.

• Radiation Oncology Journal
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• v.6 no.1
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• pp.85-91
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• 1988

For the physical characterization of neutron beam, dosimetric measurements had been performed to obtain physical data of KCCH cyclotron-produced neutrons for clinical use. The results are presented and compared with the data of other institutions from the literatures. The central axis percent depth dose, build-up curves and open and wedge isodose curve values are intermediate between that of a 4 and 6 MV X-rays. The build-up level of maximum dose was at 1.35cm and entrance dose was approximately $40\%$. Flatness of the beam was $9\%$ at Dmax and less $than{\pm}3\%$ at the depth of $80\%$ isodose line. Penumbra begond the $20\%$ line is wider than corresponding photon beam. The output factors ranged 0.894 for $6\times6cm$ field to 1.187 for $30\times30cm$ field. Gamma contamination of neutron beam was $4.9\%$ at 2 cm depth in $10\times10cm$ field.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.59-69
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• 2013

This study presents development of the ANN simulator for well placement of infill drilling in gas fields. The input data of the ANN simulator includes the production time, well location, all inter well distances, boundary inter well distance, infill well position, productivity potential, functional links, reservoir pressure. The output data includes the bottomhole pressure in addition to the production rate. Thus, it is possible to calculate the productivity and bottomhole pressure during production period simultaneously, and it is expected that this model could replace conventional simulators. Training for the 20 well placement scenarios was conducted. As a result, it was found that accuracy of ANN simulator was high as the coefficient of correlation for production rate was 0.99 and the bottomhole pressure 0.98 respectively. From the resultes, the validity of the ANN simulator has been verified. The term, which could produce Maximum Daily Quantity (MDQ) at the gas field and the productivity according to the well location was analyzed. As a result, the MDQ could be maintained for a short time in scenario C-1, which has the three infill wells nearby aquifer boundary, and a long time in scenario A-1. In conclusion, it was found that scenario A maintained the MDQ up to 21% more than those of scenarios B and C which include parameters that might affect the productivity. Thus, the production rate can be maximized by selecting the location of production wells in comprehensive consideration of parameters that may affect the productivity. Also, because the developed ANN simulator could calculate both production rate and bottomhole pressure, respectively, it could be used as the forward simulator in a various inverse model.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.331-337
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• 2001

This study was performed to develope stem analysis program(Stemwin1.0) which can be used in PC with MS-Windows operating system. Stemwin1.0 uses width of annual tree ring measured with 1/100mm unit, and calculate increments of several growth factors such as DBH, height and volume with various methods. Mean DBH can be calculated by arithmetic and quadratic mean methods. Height can be estimated by parallel line, line extending and height curve methods. Volume can be estimated by Huber, Smalian, and Spline functions. Not only Total growth, Mean Annual Increment(MAI) and Current Annual Increment(CAI) of growth factors, but also merchantable volume and height, form factor, growth rate, and merchantable volume rate are automatically calculated. Stemwin1.0 can also output accurate stem taper curve with various scale, and prepare stem taper data(diameter at different disk heights) for statistical analysis for deriving stem taper model. Stemwin1.0 can export output data and graph to Excel for more compatible use of it.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.175-181
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• 1993

Radiosurgery requires integral procedure where special devices and computer systems are needed for localization, dose planning and treatment. The aim of this work is to verify the overall mechanical accuracy of our LINAC and develop dose calculation algorithm for LINAC radiosurgery. The alignment of treatment machine and the performance testing of the entire system were extensively carried out and the basic data such as percent depth dose, off-axis ratio and output factor were measured. A three dimensional treatment planning system for stereotactic radiosurgery has been developed. We used an IBM personal computer with C programming language (IBM personal system/2, Model 80386, IBM Co., USA) for calculating the dose distribution. As a result, deviations at isocenter on gantry and table rotation for our treatment machine were acceptable since they were less than 2 mm. According to the phantom experiments, the focusing isocenter were successful by the error of less than 2 mm. Finally, the mechanical accuracy of our three dimensional planning system was confirmed by film dosimetry in sphere phantom.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.353-359
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• 2000

$(Bi_{0.15}Sb_{0.85})_2Te_3$ and $(Bi_{1-x}Sb_x)_2Te_3$ thermoelectric thin films were prepared by magnetron sputtering process, and their thermoelectric characteristics were investigated with variation of the sputtering condition and the $Sb_2Te_3$ content. The $(Bi_{0.15}Sb_{0.85})_2Te_3$ film, deposited by DC sputtering at $300^{\circ}C$ with rotating the Corning glass substrate at 10 rpm, was fully crystallized to $(Bi,Sb)_2Te_3$ phase with c-axis preferred orientation. This $(Bi_{0.15}Sb_{0.85})_2Te_3$ film exhibited the Seebeck coefficient of 185 $\mu$V/K which was higher than the values of other $(Bi_{0.15}Sb_{0.85})_2Te_3$ films fabricated with different sputtering conditions. With increasing the $Sb_2Te_3$ content, the Seebeck coefficient and electrical resistivity of p-type $(Bi_{1-x}Sb_x)_2Te_3$ (0.77$\leq$x$\leq$1.0) film were lowered. Among p-type $(Bi_{1-x}Sb_x)_2Te_3$ films, a maximum power factor of $0.79{\times}10^{-3}W/K^2-m$ was obtained at (Bi_{0.05}Sb_{0.95})_2Te_3$ composition..