• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.10-15
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• 2002

In this paper, the electrical characteristics of fabricated p+-n junction diode are demonstrated and interpreted with different theoretical calculations. Dopants distribution by boron ion implantation on silicon wafer were simulated with TRIM-code and ICECaEM simulator. In order to make electrical activation of implanted carriers, thermal annealing treatments are carried out by RTP method for 1min. at $1000^{circ}C$ under inert $N_2$ gas condition. In this case, profiles of dopants distribution before and after heat treatments in the substrate are observed from computer simulations. In the I-V characteristics of fabricated diodes, an analytical description method of a new triangular junction model is demonstrated and the results with calculated triangular junction are compared with measured data and theoretical calculated results of abrupt junction. Forward voltage drop with new triangular junction model is lower than the case of abrupt junction model. In the C-V characteristics of diode, the calculated data are compared with the measured data. Another I-V characteristics of diodes are measured after proton implantation in electrical isolation method instead of conventional etching method. From the measured data, the turn-on characteristics after proton implantation is more improved than before proton implantation. Also the C-V characteristics of diode are compared with the measured data before proton implantation. From the results of measured data, reasonable deviations are showed. But the C-V characteristics of diode after proton implantation are deviated greatly from the calculated data because of leakage currents in defect regions and layer shift of depletion by proton implantation.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.55-65
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• 2023

Soft clay is widely spread in nature and encountered in geotechnical engineering applications. The creep property of soft clay greatly affects the long-term performance of its upper structures. Therefore, it is vital to establish a reasonable and practical creep constitutive model. In the study, two updated hyperbolic equations based on the volumetric creep and deviatoric creep are respectively proposed. Subsequently, three creep constitutive models based on different creep behavior, i.e., V-model (use volumetric creep equation), D-model (use deviatoric creep equation) and VD-model (use both volumetric and deviatoric creep equations) are developed and compared. From the aspect of prediction accuracy, both V-model and D-model show good agreements with experimental results, while the predictions of the VD-model are smaller than the experimental results. In terms of the parametric sensitivity, D-model and VD-model are lower sensitive to parameter M (the slope of the critical state line) than V-model. Therefore, the D-model which is developed by incorporating the updated deviatoric creep equation is suggested in engineering applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.371-384
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• 2019

Motion perception has been tremendously improved in neuroscience and computer vision. The baseline motion perception model is mediated by the dorsal visual pathway involving the cortex areas the primary visual cortex (V1) and the middle temporal (V5 or MT) visual area. However, few works have been done on the extension of neural models to improve the efficacy and robustness of motion perception of real sequences. To overcome shortcomings in situations, such as varying illumination and large displacement, an adaptive V1-MT motion perception (Ad-V1MTMP) algorithm enriched to deal with real sequences is proposed and analyzed. First, the total variation semi-norm model based on Gabor functions (TV-Gabor) for structure-texture decomposition is performed to manage the illumination and color changes. And then, we study the impact of image local context, which is processed in extra-striate visual areas II (V2), on spatial motion integration by MT neurons, and propose a V1-V2 method to extract the image contrast information at a given location. Furthermore, we take feedback inputs from V2 into account during the polling stage. To use the algorithm on natural scenes, finally, multi-scale approach has been used to handle the frequency range, and adaptive pyramidal decomposition and decomposed spatio-temporal filters have been used to diminish computational cost. Theoretical analysis and experimental results suggest the new Ad-V1MTMP algorithm which mimics human primary motion pathway has universal, effective and robust performance.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.472-477
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• 1995

The degree of the photodoping process in Ag(100[.angs.])/a-Se$_{75}$Ge$_{25}$(1500[.angs.]) films has measured as a function of the photon energy between 1.5[eV] and 2.9[eV] with the exposing time. The "window" characteristics of Ag occur at 3400[.angs.] (3.65[eV]) and Ag is almost transparent in this region. It is shown that transmittance is almost constant (40-50%) for the wavelength ranges of our experiment. It is found that the energy gap of a unexposed a-Se$_{75}$Ge$_{25}$ film is 1.81[eV]. Ag photodoping process results in the photodarkening effect which the absorption edge shifts to the long wavelength. Especially, very large band shift (-0.3[eV]) is obtained by exposing He-Ne laser(6328[.angs.]).. We have obtained "the U-type property" for Ar He-Ne and semiconductor laser. It is associated with the variation of energy gap(E$_{g}$) with photo-dose and substantially is explained by DWP model.l.gap(E$_{g}$) with photo-dose and substantially is explained by DWP model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.71-72
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• 2008

This paper describes a circuit based simulation model for a Photovoltaic(PV) cell in order to estimate the electrical behavior of the solar cell module with changes of environmental parameters such as shunt resistance, series resistance, temperature and irradiance. An accurate I-V model of PV module is presented based on the Shockley diode model. The general model was implemented on Matlab scrip file, and used irradiance and temperature as variables and outputs of the I-V characteristic. A typical PV module was used for the evaluation, and results was compared with reference taken directly from the manufacturer's published curves leading to excellent agrement with the theoretical prediction.

• Journal of ILASS-Korea
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• v.21 no.1
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• pp.47-52
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• 2016

This paper describes the modeling of CNG direct injection using gaseous sphere injection model. Simulation of CNG direct injection does not need break up and evaporation model compared to that of liquid fuel injection. And very fine mesh is needed near the injector nozzle to resolve the inflow boundary. Therefore it takes long computation time for gaseous fuel injection simulation. However, simulation of CNG direct injection could be performed with the coarse mesh using gaseous sphere injection model. This model was integrated in KIVA-3V code and RNG $k-{\varepsilon}$ turbulence model needs to be modified because this model tends to over-predict gas jet diffusion. Furthermore, we preformed experiments of gaseous fuel injection using PLIF (planar laser induced fluorescence)method. Gaseous fuel injection model was validated against experiment data. The simulation results agreed well with the experiment results. Therefore gaseous sphere injection model has the reliability about gaseous fuel direct injection. And this model was predicted well a general tendency of gaseous fuel injection.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.17-20
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• 2002

This paper proposes a new 75 fuzzy model approximation method which reduces error in nonlinear fuzzy model approximation over the V-type decision rules. Employing rational Bezier curves used in computer graphics to represent curves or surfaces, the proposed method approximates the decision rule by constructing a tractable linear equation in the highly non-linear fuzzy rule interval. This algorithm is applied to the self-adjusting air cushion for spinal cord injury patients to automatically distribute the patient's weight evenly and balanced to prevent decubitus. The simulation results indicate that the performance of the proposed method is bettor than that of the conventional TS Fuzzy model in terms of error and stability.

• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.183-193
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• 1986

Full scale HDR containment experiment series pointed out that the previous containment analysis models have a number of shortcomings. One of them is on the calculational model of short term (0~2sec) pressure difference. The pressure differences between subcompartments are dependent on the flow rate, fluid density, head loss coefficient, and flow area ratio. It, however, is not known that any of them is largely attributed to the disagreement of pressure difference between the measured and the calculated values. In this study, the head loss coefficients are expressed with another form to improve the analytic model. The pressure and the pressure difference are evaluated by using COMPARE code with new correlation, and the results show better agreements with experimental values for V.42 test, but overestimate the measured values for V, 43 and underestimate for V.44.

• Journal of The Korean Astronomical Society
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• v.26 no.2
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• pp.89-98
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• 1993

Magnetostatic models of starspots of late type main sequence stars$(G5V\~K5V)$ have been constructed to investigate their physical characteristics by using the similarity law suggested by Schluter and Temesvary(1958) and later employed by Deinzer(1965) and Yun(1968). The starspots are assumed to be single, circular and in horizontal magnetostatic equilibrium. In the present study we considered only those model spots whose area covers less than $12\%$ of the entire stellar surface as suggested by observations. The computed surface field strength of our model spots ranges from $10^3$\;to\;several\;10^3$ gauss and their magnetic flux is found to be $10\~100$ times that of sunspots. The field strength is sensitive to spectral type, which increases with later spectral type. In contrast to the field strength, the area of starspots depends strongly on the total magnetic flux. Finally, it is noted that the computed field strength of model spots belonging to $G0V\~G5V$ falls below the equipartition field strength at their parent stellar surface unless the coverage is less than $2\%$. This suggests that the observed spot on $G0V\~G5V$ stars is likely to be a group of small starspots.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.5
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• pp.290-294
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• 2003

Using a backpropagation neural network (BPNN), a high power semiconductor device was empirically modeled. The device modeled is a n-LDMOSFET and its electrical characteristics were measured with a HP4156A and a Tektronix curve tracer 370A. The drain-source current $(I_{DS})$ was measured over the drain-source voltage $(V_{DS})$ ranging between 1 V to 200 V at each gate-source voltage $(V_{GS}).$ For each $V_{GS},$ the BPNN was trained with 100 training data, and the trained model was tested with another 100 test data not pertaining to the training data. The prediction accuracy of each $V_{GS}$ model was optimized as a function of training factors, including training tolerance, number of hidden neurons, initial weight distribution, and two gradients of activation functions. Predictions from optimized models were highly consistent with actual measurements.