• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.395-398
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• 2006

Forging is applied for many industrial fields. Also, it is applied to hose nipple. Stress and metal analysis is finding method of forging possibility and we predict this possibility by finite element forging analysis. But there are also many manufacturing procedure after forging, and metal texture is varied by additional heat treatment or coating. So this research is focused on the measuring and analysis of plastic residual stress distribution at overall manufacturing procedure. From raw material to final product we measured real residual stress at each manufacturing procedure by X ray diffract meter, and simulated another procedure except forging by nonlinear finite element analysis. Also we showed how Zn-Ni coating is more contributable to metal strength than Zn coating. By this research we make final conclusion that process analysis must be observed from raw material to final manufacturing state for robust design.

• Proceedings of the Korea Water Resources Association Conference
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• 1998.05a
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• pp.632-637
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• 1998

The purpose of this study of this study is to find tide and tidal current variation by three dimensional numerical model of tide and tidal current in the bay of Cheonsu in Korea. On the basis of the observed data on water temperature and salinity data and wind data of summer(July) in the bay of Cheonsu in Korea, water circulation in the bay of Cheonsu is investigated with use of a robust diagnostic numerical model, including calculated co-range and co-tidal charts of M2 tide are similar to the observed ones. The residual flow Pattern at the surface layer during summer formed clockwise circulation in the front coastal the dike of the Sosam A zone(Ganwor island) and Taeju island. The residual flow pattern at the 15m layer during formed clockwise circulation in the front Taeju island. The residual flow Pattern at the surface layer formed anti-clockwise circulation in the upper Sangmok and Naepasu island.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.47-53
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• 2000

Saemangeum coastal area is being constructed the 33km sea dike and 40,000ha reclamation area. The purpose of this study is to find the residual circulations in spring before and after the dike construction by a robust diagnostic and prognostic numerical model. Heat flux at the sea surface in May was adopted on the basis of the daily inflow of solar radiation at the earth surface, assuming an average atmospheric transmission and no clouds, as a function of latitude and time of year(George L.P.,J. E. William,1990). The discharge from the Geum, the Mankyung and the Dongjin rivers was adopted on the basis of experience formula of river flow in May(The M. of C.,Korea, 1993). Water temperature and salinity along the open boundaries are obtained from the results of field observations. The results of spring of the residual flow in the Saemangeum coastal area by a prognostic numerical model lead to the following conclusions: Water temperature in spring is the highest, salinity is the lowest and density is the lowest at the upper layer near the coast after the dike construction. The flow pattern at the upper layer during spring is anti-clockwise circulation between Wi and Shinsi islands. The flow pattern at the lower layer is clockwise circulation between Wi and Shinsi islands.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.35-42
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• 2000

The sway control problem of the pendulum motion of a container hanging on the trolly, which transports containers from a container ship to trucks, is considered in the paper. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, the trolley motion control strategy is introduced and applied. But in this paper, we introduce and synthesize a new type of swing motion control system. In this control system, a small auxiliary mass is installed on the spreader. And the actuator reacts against the auxiliary mass, applying intertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we apply the LMI approach and simultaneous optimization design method to design the anti-swing motion control system for the controlled plant. And the simulation result shows that the proposed control strategy is shown to be robust to disturbances like winds and initial sway motion.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.89-99
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• 2018

Downtime and malfunction of industrial rotor machines represents a crucial cost burden and productivity loss. Fault diagnosis of this equipment has recently been carried out to detect their fault(s) and cause(s) by using fault classification methods. However, these methods are of limited use in detecting rotor faults because of their hypersensitivity to unexpected and different equipment conditions individually. These limitations tend to affect the accuracy of fault classification since fault-related features calculated from vibration signal are moved to other regions or changed. To improve the limited diagnosis accuracy of existing methods, we propose a new approach for fault diagnosis of rotor machines based on the model generated by supervised learning. Our work is based on feature residual values from vibration signals as fault indices. Our diagnostic model is a robust and flexible process that, once learned from historical data only one time, allows it to apply to different target systems without optimization of algorithms. The performance of the proposed method was evaluated by comparing its results with conventional methods for fault diagnosis of rotor machines. The experimental results show that the proposed method can be used to achieve better fault diagnosis, even when applied to systems with different normal-state signals, scales, and structures, without tuning or the use of a complementary algorithm. The effectiveness of the method was assessed by simulation using various rotor machine models.

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.349-360
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• 1995

This paper deals with the robustness properties of the minimum disparity estimation in linear regression models. The estimators defined as statistical quantities whcih minimize the blended weight Hellinger distance between a weighted kernel density estimator of the residuals and a smoothed model density of the residuals. It is shown that if the weights of the density estimator are appropriately chosen, the estimates of the regression parameters are robust.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.156-158
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• 2009

New liquid crystal (LC) host mixtures and reactive mesogens (RMs) designed for the Polymer Sustainable Vertically Aligned (PS-VA) mode have been developed. The novel combination of LC host mixture with RMs enables to show superior LC display performance with high reliability and to contribute for the robust LC panel production process.

• Journal of Korean Society for Quality Management
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• v.25 no.2
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• pp.47-59
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• 1997

In this paper we develop computational algorithms to calculate M-estimators of regression parameters from right-censored data that are naturally collected in quality control. In the case of M-estimators, a new statistical method is also introduced to incorporate concomitant scale estimation in the presence of right censoring on the observed responses. Furthermore, we illustrate this by simulations.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.190-194
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• 2008

This paper presents a speaker identification technique which is one of the basic techniques of the ubiquitous robot companion. Though the conventional mel-frequency cepstral coefficients guarantee high performance of speaker identification in clean condition, the performance is degraded dramatically in noise condition. To overcome this problem, we employed the relative autocorrelation sequence mel-frequency cepstral coefficient which is one of the noise robust features. However, there are two problems in relative autocorrelation sequence mel-frequency cepstral coefficient: 1) the limited information problem. 2) the residual noise problem. In this paper, to deal with these drawbacks, we propose a multi-streaming method for the limited information problem and a hybrid method for the residual noise problem. To evaluate proposed methods, noisy speech is used in which air conditioner noise, classic music, and vacuum noise are artificially added. Through experiments, proposed methods provide better performance of speaker identification than the conventional methods.

• Geophysics and Geophysical Exploration
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• v.10 no.2
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• pp.124-130
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• 2007

Least squares ($l^2$ norm) solutions of seismic inversion tend to be very sensitive to data points with large errors. The $l^1$ norm minimization gives more robust solutions, but usually with higher computational cost. Iteratively reweighted least squares (IRLS) method gives efficient approximate solutions of these $l^1$ norm problems. I propose an efficient implementation of the IRLS method for a hybrid $l^1/l^2$ minimization problem that behaves as $l^2$ norm fit for small residual and $l^1$ norm fit for large residuals. The proposed algorithm shows more robust characteristics to the decision of the threshold value than the l1 norm IRLS inversion does with respect to the threshold value to avoid singularity.