• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.1
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• pp.17-19
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• 2006

This paper presents the design of an electromagnetic system such as jumping ring system, and also considers the characteristics of dynamics for system with initial parameter. For the propose of system analysis, the MATLAB tool is to solve coupled differential equations with inductances and mutual inductance. To apply a real electromagnetic system, this paper implements the jumping ring system using design parameters, and analyzes the jumping ring system with proposal step.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.359-361
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• 1993

In this paper, a variable structure controller with time-varying sliding surface is proposed for robot manipulators. The proposed time-varying sliding surface ensures the existence of sliding mode from an initial state, while the contentional sliding surface cannot achieve the robust performance against parameter variations and disturbances before the sliding mode occurs. Therefore, error transient can be fully prescribed in advance for all time. Furthermore, it is shown that the overall system is globally exponetially stable. The efficiency of the proposed method for the trajectory tracking has been demonstrated by simulations.

• Textile Coloration and Finishing
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• v.2 no.1
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• pp.21-30
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• 1990

In order to obtain high dye uptake initially, polyethylene terephthalate (PET) filaments were dyed with C.I.Disperse Orange 3 and Red 1 in mixed solvents of tetrachloroethylene acidic solvent, ethyl alcohol and tetrachloroethylene basic solvent, DMF. The dyeing behavior in the mixed solvent of tetrachloroethylene and basic solvent, DMF, the initial uptake of disperse dyes increased rapidly. The shrinkage of PET increased when the solubility parameter values of PET fiber and mixed solvent approached graduately.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.10
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• pp.575-587
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• 2004

In this paper. a new Fast Expectation-Maximization algorithm(FEM) is proposed. Firstly the K-means algorithm is modified to reduce the number of iterations for finding the initial values that are used as the initial values in EM process. Conventionally the Initial values in K-means clustering are chosen randomly. which sometimes forces the process of clustering converge to some undesired center points. Uniform partitioning method is added to the conventional K-means to extract the proper initial points for each clusters. Secondly the effect of posterior probability is emphasized such that the application of Maximum Likelihood Posterior(MLP) yields fast convergence. The proposed FEM strengthens the characteristics of conventional EM by reinforcing the speed of convergence. The superiority of FEM is demonstrated in experimental results by presenting the improvement results of EM and accelerating the speed of convergence in parameter estimation procedures.

• The Journal of Advanced Prosthodontics
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• v.16 no.3
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• pp.174-188
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• 2024

PURPOSE. The purpose of this study was to investigate the effects of surface treatments, liquids, and aging on color, translucency, and surface properties of monolithic ceramics. MATERIALS AND METHODS. Lithium disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) ceramics (n = 135 each) were cut and divided into three groups [crystallization+glaze (single stage), crystallization-glaze (two stages), and crystallization-polish (two stages)]. One sample from each group was examined using scanning electron microscopy (SEM). Remaining samples were divided into four subgroups (distilled water, coffee, grape juice, and smoothie) (n = 11 each), stored for 12 d in the respective liquids, and thermally aged. One sample from each subgroup was analyzed using SEM. The color, gloss, and roughness values of the samples were analyzed after surface treatment (initial) and storage under different liquids+aging conditions. The initial data and both the aged data and data change values were analyzed using robust two- and three-way analyses of variance. RESULTS. The glazed groups exhibited smoother surfaces. Ceramic type and ceramic-surface treatment interactions affected the initial translucency parameter (TP) (P < .001) and the initial and aged roughness values (P ≤ .001). Surface treatment type affected the color change (P < .001), and ceramic type affected the aged TP values (P < .001). Type of ceramic, surface treatment, and their interactions affected both the initial and aged gloss (P ≤ .001) and TP change values (P ≤ .015). Surface treatment type and ceramic-surface treatment interactions affected the gloss change values (P ≤ .001). CONCLUSION. Although both ceramics and all surface treatments are clinically applicable, crystallization-glaze is recommended. When gloss and smoothness are important or when translucency is important, ZLS or LDS may be preferred, respectively.

• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.471-477
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• 1999

Many researches have been performed whether electrical stimulation could be used for diagnosis and treatment on the auditory system impairment. Unfortunately, there were no standard methods or theoretical background for choosing stimulus conditions because of the lack of understanding on the transmission of electrical stimulation through the auditory pathway. This research was conducted to observe the effect of electrical stimulation on the tinnitus-induced animals. Nine guniea pigs were used for the experment and divided into two groups, five animals for the experimental group(A) and four animals for the control group(B). Experimental conditions were divided into four steps, before tinnitus induction and 1, 6, 12 hours after tinnitus induction using salicylate based on the Jastreboff model. In each experimental condition, ABR and ECochG were obtained, and autocorrelation coefficients were calculated from normalized waveforms based on rms values. Sum of all the autocorrelation coefficients was extracted as a parameter to observe the changes between before and after the electrical stimulation. As a result, ABR parameter values were rapidly increased 6 hours after tinnitus induction, the gradually returned back to the initial state. On the other hand, when electrical stimulation was applied, parameter values did not change compared with the initial sate. Parameter values of ECochG showed that the effect of electrical stimulation appeared 12 hours after the tinnitus induction. It was concluded that an electrical stimulation to the tinnitus-induced model changes the correlation coefficients of ABR and ECochG waveforms.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1105-1116
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• 2014

A stochastic rainfall model, NSRPM (Neyman-Scott Rectangular Pulse Model), is able to reflect the cluster characteristics of rainfall events which is unable in the RPM (Rectangular Pulse Model). Therefore NSRPM has advantage in the hydrological applications. The NSRPM consists of five model parameters and the parameters are estimated using optimization techniques such as DFP (Davidon-Fletcher-Powell) method and genetic algorithm. However the DFP method is very sensitive in initial values and is easily converge to local minimum. Also genetic algorithm has disadvantage of long computation time. Nelder-Mead method has several advantages of short computation time and no need of a proper initial value. In this study, the applicability of parameter estimation methods was evaluated using rainfall data of 59 national rainfall networks from 1973-2011. Overall results demonstrated that accuracy in parameter estimation is in the order of Nelder-Mead method, genetic algorithm, and DFP method.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.187-197
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• 2005

In this paper, we propose a method to estimate camera motion parameter based on invariant point features, Typically, feature information of image has drawbacks, it is variable to camera viewpoint, and therefore information quantity increases after time, The LM(Levenberg-Marquardt) method using nonlinear minimum square evaluation for camera extrinsic parameter estimation also has a weak point, which has different iteration number for approaching the minimal point according to the initial values and convergence time increases if the process run into a local minimum, In order to complement these shortfalls, we, first proposed constructing feature models using invariant vector of geometry, Secondly, we proposed a two-stage calculation method to improve accuracy and convergence by using 2D homography and LM method, In the experiment, we compared and analyzed the proposed method with existing method to demonstrate the superiority of the proposed algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.147-154
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• 2015

In this paper, we employed a model which defines the sensitivity according to the background luminance, so called JND (Just Noticeable Difference), and applied to the video coding. The proposed method finds out the maximum possible quantization parameter for the current unit based on the threshold of JND model and reduce the bitrate with similar perceptual quality. It selects the higher quantization parameter and reduce the bitrate when the reconstructed signal which is coded with higher quantization parameter is in a range of allowance based on the JND threshold, i.e. the signal has the similar perceptual quality compared to that is coded with the initial quantization parameter. The proposed algorithm was implemented on HM16.0, which is a reference software of the latest video coding standard HEVC (High Efficiency Video Coding) and the coding performance was evaluated. Compared to HM16.0, the proposed algorithm achieved maximum 20.21% and 6.18% of average bitrate reduction with the similar perceptual quality.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1447-1454
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• 2014

In H.264 standard, an intra frame is the first frame of a GOP (Group of Pictures) and all macroblocks of an intra frame are encoded using the same quantization parameter. In addition, an intra frame is used for encoding the following frames of the same GOP so the encoding results of an intra frame affect the encoding results of the entire GOP. Thus, it is important to find the optimal quantization parameter of an intra frame for improving the quality of a GOP. In this paper, we propose an searching method for an optimal quantization parameter of an intra frame in real time. The proposed method uses a gradient descent method to find the optimal value based on characteristics of the optimal quantization parameters. Experimental results show that the proposed method captures the characteristics of the optimal quantization parameter and accurately estimates the optimal value.