• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.112-121
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• 1997

In this paper, we study a model parameter compensation method for noise-robust speech recognition. We study model parameter compensation on a sentence by sentence and no other informations are used. Parallel model combination(PMC), well known as a model parameter compensation algorithm, is implemented and used for a reference of performance comparision. We also propose a modified PMC method which tunes model parameter with an association factor that controls average variability of gaussian mixtures and variability of single gaussian mixture per state for more robust modeling. We obtain a re-estimation solution of environmental variables based on the expectation-maximization(EM) algorithm in the cepstral domain. To evaluate the performance of the model compensation methods, we perform experiments on speaker-independent isolated word recognition. Noise sources used are white gaussian and driving car noise. To get corrupted speech we added noise to clean speech at various signal-to-noise ratio(SNR). We use noise mean and variance modeled by 3 frame noise data. Experimental result of the VTS approach is superior to other methods. The scheme of the zero order VTS approach is similar to the modified PMC method in adapting mean vector only. But, the recognition rate of the Zero order VTS approach is higher than PMC and modified PMC method based on log-normal approximation.

• Geophysics and Geophysical Exploration
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• v.3 no.2
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• pp.48-52
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• 2000

We have calculated and analyzed the electromagnetic responses of buried conductive pipes due to a horizontal magnetic dipole source on the pound using a three-dimensional (3-D) finite element method to provide useful guidelines for designing electromagnetic pipe locator and for field operation of the system. For single buried pipe, the horizontal component and the horizontal difference of the vertical component of magnetic field show peaks above the pipe. When comparing the width of response curves of both cases around the peak, horizontal difference of vertical component of magnetic field shows much narrower peak, 2 times narrower at a half of maximum amplitude, than that of horizontal component of magnetic field. Accordingly, we can pinpoint the horizontal location of pipe on the ground more accurately by measuring the horizontal difference of vertical component of magnetic fold. Moreover, it will have a merit in determining the depth of pipe, because the equation for depth estimation is defined just above the pipe. When there are two buried pipes separated by two meters with each other, the response of horizontal difference of vertical component of magnetic field has two separate peaks each of which is located above the pipe whereas horizontal magnetic field response has only one peak above the pipe just below the transmitter. Thus, when there exist more than a buried pipe, measuring the horizontal difference of vertical magnetic field can effectively detect not only the pipe under transmitter but also adjacent ones. The width of response curves also indicates higher resolving ability of horizontal difference of vertical component of magnetic field.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.6
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• pp.571-576
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• 2002

There have been a lot of considerations dealing with improving the performance of neuro-fuzzy system. The studies on the neuro-fuzzy modeling have largely been devoted to two approaches. First is to improve performance index of system. The other is to reduce the structure size. In spite of its satisfactory result, it should be noted that these are difficult to extend to high dimensional input or to increase the membership functions. We propose a novel neuro-fuzzy system based on the efficient clustering method for initializing the parameters of the premise part. It is a very useful method that maintains a few number of rules and improves the performance. It combine the various algorithms to improve the performance. The Expectation-Maximization algorithm of Gaussian mixture model is an efficient estimation method for unknown parameter estimation of mirture model. The obtained parameters are used for fuzzy clustering method. The proposed method satisfies these two requirements using the Gaussian mixture model and neuro-fuzzy modeling. Experimental results indicate that the proposed method is capable of giving reliable performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.441-447
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• 2002

KSR-III(Korea Sounding Rocket - III), which is being developed by Space Technology R&D Division of KARI(Korea Aerospace Research Institute) will be launched in late 2002. It is a three-stage, liquid propellant rocket which can reach 250 km altitude and will carry out observation of ozone layer and scientific experiments, such as microgravity experiment, and atmospheric measurement. KSR-III is believed to be an intermediate to the launch vehicle capable of carrying a satellite to its orbit. Space Test Department of KARI performed GVT(Ground Vibration Test) fer KSR-III EM at Rocket Test Building of KARI. GVT is very important for predicting the behavior of rocket in its operation, developing flight control program and performing aerodynamic analysis. This paper gives an introduction of rocket GVT configuration and information on test procedures, techniques and results of It. In this test. to simulate free-free condition, test object hung in the air laterally by 4 bungee cords specially devised. For the excitation of test object, pure random signal by two electromagnetic shakers was used and total 22 frequency response functions were achieved. Polyreference parameter estimation was performed to identify the modal parameters with MIMO(Multi-Input-Multi-Output) method. As the result of the test, low frequency mode shapes and modal parameters below 60Hz were identified

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.294-299
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• 2008

The present study investigates the ventilation effects on smoke spreading with the rescue stations. Experiments for tunnel fires were carried out for n-heptane pool em at different fire locations, and the heat release rates (HRR) were obtained by addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.84-91
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• 2001

In in vitro cell experiments for the biological assessment of electromagnetic (EM) field, exposure system (ES) must be analyzed in terms of current density (J) and induced electric field intensity (E). Although in uniform B field, E and J in the sample medium are not distributed uniformly because of conductivity in sample dish. Thus, the precise estimation for E and J induced by uniform ELF within sample media is very important keys for successful in in vitro experiments. In this paper, we designed in vitro ELF ES with electromagnetic analysis using MATLAB simulator. Then we calculated from the measured B field to verify induced E & J distribution for random locations of cells within media in two cases of samples existence or not. ES with B field ranging from 0 to 20G consists of Helmholz coil and current generator based on the microprocessor. Also, we developed ELFES for each B field generation as uniform and non-uniform modes.

• Science of Emotion and Sensibility
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• v.10 no.1
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• pp.99-111
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• 2007

In order to identify tactile sensibility factors of traditional silk fabrics and to provide prediction models for the sensibility factors by mechanical properties, seventeen different traditional silk fabrics were evaluated in terms of both tactile sensation and sensibility by using a modified magnitude estimation line scale Gongdan and Newttong with lower values for surface roughness(SMD), bending rigidity(B), and compression resilience(RC) were rated as softer, smoother, fluffier, and more pliable in tactile sensation than any other traditional silk fabrics whereas Nobangju haying higher B, SMD, and tensile resilience(RT) was touched as crisper, more rustling, and springier. Three different tactile sensibility factors including 'Feminine', 'Natural', and 'Casual' were obtained significantly by grouping fifteen different tactile sensibility descriptors. In the prediction models sensibility 'Feminine' was explained positively by SMD, which was supported by the fact that both Gongdan and Newtton were perceived as more feminine. Sensibility 'Natural' that was felt stronger as for Myoungju and Sa was predicted negatively by both fabric thickness(T) and RT. Finally, RC, elongation at maximum load (EM), and T predicted sensibility 'Casual' negatively, which results in its higher factor scores for Myoungju and Shantung, respectively.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.83-89
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• 2010

The objective of this study was to investigate the effect of the environmental and genetic factors on the carcass traits of Korean cattle. We have used the data of 22,954 Korean cattle slaughtered from 2005 to 2009 in Gyeongnam region and estimated the genetic parameters of 36,868 cattle including the pedigree individuals by means of EM-REML analytical method. In summary, the heritability of the carcass weight, eye muscle area, backfat thickness and marbling score was 0.39, 0.30, 0.33 and 0.62, respectively. The carcass weight and the eye muscle area showed high correlation between them with the genetic correlation of 0.86 and the phenotypic correlation of 0.72. The high heritability of marbling score is assumed to be the result of focusing the breed improvement on the quality of the meat. Through this study, it is considered that the Korean cattle in Gyeongnam region are improving, which will thus contribute to the increase of the farmer's income. Additional study on the economic trait must be carried out to obtain clearer results that will lead to further improvement of Korean cattle.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.89-105
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• 2017

This study utilized 32,312 records of 17 linear type and 10 conformation traits(including final scores) of Hanwoo cows in the KAIA(Korea Animal Improvement Association) ('09~'10), with 60,556 animals in the pedigree file. Traits included stature, body length, strength, body depth, angularity, shank thickness, rump angle, rump length, pin bone width, thigh thickness, udder volume, teat length, teat placement, foot angle, hock angle, rear leg back view, body balance, breed characteristic, head development, forequarter quality, back line, rump, thigh development, udder development, leg line, and final score. Genetic and residual(co) variances were estimated using bi-trait pairwise analyses with EM-REML algorithm. Herd-year-classifier, year at classification, and calving stage were considered as fixed effects with classification months as a covariate. The heritability estimates ranged from 0.03(teat placement) to 0.42(body length). Rump length had the highest positive genetic correlation with pin bone width(0.96). Moreover, stature, body length, strength, and body depth had the highest positive genetic correlations with rump length, pin bone width, and thigh thickness(0.81-0.94). Stature, body length, strength, body depth, rump length, pin bone width, and thigh thickness traits also had high positive genetic correlations.

• Geophysics and Geophysical Exploration
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• v.21 no.1
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• pp.15-25
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• 2018

Seismic inversion is a high-resolution tool to delineate the subsurface structures which may contain oil or gas. On the other hand, marine controlled-source electromagnetic (mCSEM) inversion can be a direct tool to indicate hydrocarbon. Thus, the joint inversion using both EM and seismic data together not only reduces the uncertainties but also takes advantage of both data simultaneously. In this paper, we have developed a simultaneous joint inversion approach for the direct estimation of reservoir petrophysical parameters, by linking electromagnetic and seismic data through rock physics model. A cross-gradient constraint is used to enhance the resolution of the inversion image and the maximum likelihood principle is applied to the relative weighting factor which controls the balance between two disparate data. By applying the developed algorithm to the synthetic model simulating the simplified gas field, we could confirm that the high-resolution images of petrophysical parameters can be obtained. However, from the other test using the synthetic model simulating an anticline reservoir, we noticed that the joint inversion produced different images depending on the model constraint used. Therefore, we modified the algorithm which has different model weighting matrix depending on the type of model parameters. Smoothness constraint and Marquardt-Levenberg constraint were applied to the water-saturation and porosity, respectively. When the improved algorithm is applied to the anticline model again, reliable porosity and water-saturation of reservoir were obtained. The inversion results indicate that the developed joint inversion algorithm can be contributed to the calculation of the accurate oil and gas reserves directly.