• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3C
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• pp.251-256
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• 2009

In this paper, we propose a new method with the improved continuity performance of overlap and add speech signal synthesis method using damping harmonic amplitude parameter. The existing method uses the average value of past and current parameters for the sinusoidal amplitude used as the weight of phase error function. But, the proposed method extracts the more accurate sinusoidal amplitude by using a correlation between the original signals and the synthesized signals for the sinusodal amplitude used as the weights. To verify the performance of the proposed method, we observed the average differential error value between the synthesized signals.

• International Journal of Control, Automation, and Systems
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• v.2 no.1
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• pp.83-91
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• 2004

The purpose of this paper is to obtain an accurate nonlinear system model to test various control schemes for a motion control system that requires high speed, robustness and accuracy. An industrial sewing machine equipped with a Brushless DC motor is considered. It is modeled by a neural network that is configured as an output-error dynamical system. The identified model is essentially a one step ahead prediction structure in which past inputs and outputs are used to calculate the current output. Using the model, a 2 degree-of-freedom PID controller to compensate the effects of disturbance without degrading tracking performance has been de-signed. In this experiment, it is not preferable for safety reasons to tune the controller online on the actual machinery. Experimental results confirm that the model is a good approximation of sewing machine dynamics and that the proposed control methodology is effective.

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.168-177
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• 2007

A neural network model to evaluate the neutron exposure on the reactor pressure vessel inner diameter was developed. By using the three dimensional synthesis method described in Regulatory Guide 1.190, a simple linear equation to calculate the neutron spectrum on the reactor pressure vessel was constructed. This model can be used in a quick estimation of fast neutron flux which is the most important parameter in the assessment of embrittlement of reactor pressure vessel. This model also used in the selection of an optimum core loading pattern without the neutron transport calculation. The maximum relative error of this model was less than 3.4% compared to the transport calculation for the calculations from cycle 1 to cycle 23 of Kori unit 1.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.234-240
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• 2010

In order to predict coastal environmental changes caused by coastal development and effectively manage marine environment, the exact information about water level changes and hydrodynamic circulation is essential. However, most of the environmental impact assessment has been using only limited tidal constituents in the numerical tide model to predict the real tide and tidal currents caused by the synthesis of many other tidal constituents, which causes an error in the environmental impact assessment. In this study, a method, which uses the limited tidal constituents at the offshore open boundaries and the observed tide at the inner or nearby point to predict the real tide in the model domain accurately, is suggested. Tidal and tidal currents predicted by the suggested method agreed well with the observations.

• Speech Sciences
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• v.10 no.4
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• pp.7-21
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• 2003

Sums-of-Products models were built for segment duration prediction of spoken Korean. An experiment for the modelling was carried out to apply the results to Korean text-to-speech synthesis systems. 670 read sentences were analyzed. trained and tested for the construction of the duration models. Traditional sequential rule systems were extended to simple additive, multiplicative and additive-multiplicative models based on Sums-of-Products modelling. The parameters used in the modelling include the properties of the target segment and its neighbors and the target segment's position in the prosodic structure. Two optimisation strategies were used: the downhill simplex method and the simulated annealing method. The performance of the models was measured by the correlation coefficient and the root mean squared prediction error (RMSE) between actual and predicted duration in the test data. The best performance was obtained when the data was trained and tested by ' additive-multiplicative models. ' The correlation for the vowel duration prediction was 0.69 and the RMSE. 31.80 ms. while the correlation for the consonant duration prediction was 0.54 and the RMSE. 29.02 ms. The results were not good enough to be applied to the real-time text-to-speech systems. Further investigation of feature interactions is required for the better performance of the Sums-of-Products models.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.33-38
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• 1999

Muscle based face image synthesis is one of the most realistic approach to realize life-like agent in computer. Facial muscle model is composed of facial tissue elements and muscles. In this model, forces are calculated effecting facial tissue element by contraction of each muscle strength, so the combination of each muscle parameter decide a specific facial expression. Now each muscle parameter is decided on trial and error procedure comparing the sample photograph and generated image using our Muscle-Editor to generate a specific race image. In this paper, we propose the strategy of automatic estimation of facial muscle parameters from 2D marker movement using neural network. This also 3D motion estimation from 2D point or flow information in captered image under restriction of physics based fare model.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.108-114
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• 2002

This paper describes the design of a robust adaptive controller for a nonlinear dynamical system with unknown nonlinearities. These unknown nonlinearities are approximated by multilayered neural networks (MNNs) whose parameters are adjusted on-line, according to some adaptive laws far controlling the output of the nonlinear system, to track a given trajectory. The main contribution of this paper is a method for considering input constraint with a rigorous stability proof. The Lyapunov synthesis approach is used to develop a state-feedback adaptive control algorithm based on the adaptive MNN model. An overall control system guarantees that the tracking error converges at about zero and that all signals involved are uniformly bounded even in the presence of input saturation. Theoretical results are illustrated through a simulation example.

• The Journal of the Acoustical Society of Korea
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• v.24 no.7
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• pp.402-409
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• 2005

In this paper. we propose a coding method using a matching pursuit algorithm in a strongly periodic highband signal. Also. we propose an efficient quantizer for the estimated parameters : spectral magnitude and phase. Based on the error concealment principle and sinusoidal model. the MP algorithm requires the high-precision pitch period estimation. To estimate more accurate pitch period. the refined pitch obtained from lowband speech is used. which increases the efficiency of bit allocation. The spectral magnitude parameters are quantized by the method which is combined with MDCT (Modified Discrete Cosine Transform) and multi-stage structure. The spectral phase quantizer uses the $2{\pi}$ modular characteristic of phases and the weighted function by spectral magnitudes. To evaluate the efficiency of the proposed method. we applied it to analysis-by-synthesis system. Furthermore we suggest the possibillity of scalable wideband speech codecs based on band-split structure.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.488-493
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• 1994

The global stability of model reference adaptive control system (MRACS) in the ideal case was resolved in the 1980's. Hoever the improvement of the transient, behaviour of MRACS has not been discussed sufficiently even in the ideal case. Only a few attempts have so far been made at the application of MRACS to the practical systems in contrast to the theoretical systematization. Therefore, when we consider the practical usage of MRACS it is necessary to develop an improved design scheme with respect to transient behaviour. In this paper, we propose two design schemes improving transient behaviour of MRACS by mollifying the input synthesis in the conventional design scheme of MRACS. We present a design scheme of MRACS in which we utilize the design approach of variable structure system(VSS). After describing the above design scheme, we also propose the improved design scheme in which we introduce the dead-zone decided by the magnitude of the output-error between the plant and the reference model. The effectiveness of the proposed two design schemes are shown through computer simulations. As the results, by using these methods, the convergence of the transient response is greatly improved in comparison with the conventional one.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.421-428
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• 2019

This paper describes a methode to extract yellow pigment from curcuma and turmeric containing natural color curcumin whose target color indexes of L, a, and b were 87.0 7.43, and 88.2, respectively. The pH range and extraction temperature used for the reaction surface analysis method were from pH 3 to pH 7 and between 40 and $70^{\circ}C$, respectively for both natural products. A central synthesis planning model combined with the method was used to obtain optimal extraction conditions to produce the color close to target. Results and regression equations show that the color space and difference of curcuma and turmeric have the greatest influence on the value. In the case of curcuma, the optimum conditions to satisfy all of the response theoretical values of color coordinates of L (74.67), a (5.69), and b (70.08) were at the pH and temperature of 3.43 and $54.8^{\circ}C$, respectively. The experimentally obtained L, a, and b, values under optimal conditions were 72.92, 5.32, and 72.17, respectively. For the case of turmeric, theoretical numerical color coordinates of L, a, and b, under the pH of 5.22 and temperature of $50.4^{\circ}C$ were 82.02, 7.43, and 72.86 respectively. Whereas, the experiment results were L (81.85), a (5.39), and b (71.58). Both cases showed an error range within 1%. Therefore, it is possible to obtain a low error rate when applying the central synthesis planning model to the reaction surface analysis method as an optimization process of the dye extraction of natural raw materials.