• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.287-297
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• 2018

To improve the performance of sensorless induction motor (IM) drives, a novel speed estimation method based on the real-time adaptive extended Kalman filter (RAEKF) is proposed in this paper. In this algorithm, the fuzzy factor is introduced to tune the measurement covariance matrix online by the degree of mismatch between the actual innovation and the theoretical. Simultaneously, the fuzzy factor can be continuously self-tuned tuned by the fuzzy logic reasoning system based on Takagi-Sugeno (T-S) model. Therefore, the proposed method improves the model adaptability to the actual systems and the environmental variations, and reduces the speed estimation error. Furthermore, a simple exponential function based on the fuzzy theory is used to reduce the computational burden, and the real-time performance of the system is improved. The correctness and the effectiveness of the proposed method are verified by the simulation and experimental results.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2343-2349
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• 1999

The hyper-geometric distribution software reliability growth model (HGDM) was recently developed and successfully applied to real data sets. The HGDM considers the sensitivity factor as a parameter to be estimated. In order to reflect the random behavior of the test-and-debug process, this paper generalizes the HGDM by assuming that the sensitivity factor is a binomial random variable. Such a generalization enables us to easily understand the statistical characteristics of the HGDM. It is shown that the least squares method produces the identical results for both the HGDM and the generalized HGDM. Methods for computing the maximum likelihood estimates and predicting the future outcomes are also presented.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.531-536
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• 2014

There are trapping and stripping methods as the technique to remove the dither motion from RLG(Ring Laser Gyro) output. V/F converter output of angular sensor to measure the dither motion is used in stripping method. But bias and scale factor error is always included in V/F converter output and is a critical limiting factor for the wide application of stripping method to RLG. Therefore there have been many researches to solve this problem. The method to accurately estimate the bias and scale factor error of V/F converter using measurements of the angular sensor acquired at data sampling rate of INS is presented in this paper. To this end, stripping technique based on model of dither motion is newly applied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.1047-1052
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• 2010

Influence of lateral spring constant on energy dissipation and load reduction factor with erespect to lateral vibration of steel sheet pile installed by vibratory pile driver. Energy dissipation and load reduction factor varying with free length of steel sheet pile are more affected by eccentricity than flexural rigidity of steel sheet pile regardless of the magnitudes of lateral spring constants. Load reduction factors were converged when lateral spring constant was equal or larger than 10000N/m.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.603-609
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• 2020

The purpose of this study is to research dampers, which are applied mainly to buildings adjacent to the coast, such as nuclear facilities, and used for ventilation and can safely protect lives and equipment in emergency situations. Comparing the equivalent stress for three models with hinge reinforcement and support reinforcement based on the early design model for Damper, in the Base model, the highest stress occurred in the part of hinge, especially in the centrally mounted hinge, and after reinforced the hinge, it was occurred in the rear support. For models reinforced hinges and supports, it is considered that reinforcement for stiffness will be required in the future as it entered within the range of allowable stress. For the safety factor distribution, the minimum safety ratio was sufficiently secured at least 1 and was high at the edge of the Damper frame and the Blade. As the hinge was reinforced, the safety factor distribution of Blade was increased, and it was verified that the safety factor was secured through the support reinforcement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3295-3300
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• 2012

Three Dimensional finite element method (FEM) was used to obtain the stress intensity factor for subsurface cracks and surface cracks existing in inhomogeneous materials. A geometry model, i.e. a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model. Nodes are generated by the bubble packing, and ten-noded quadratic tetrahedral solid elements are generated by the Delaunay triangulation techniques. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze interaction effects of two dissimilar semi-elliptical cracks in a plate subjected to uniform tension.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.1
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• pp.47-57
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• 2019

The purpose of the study was to explore effective satisfaction factors for continuous partnerships between fashion companies and artists. A questionnaire was developed by the researchers and results were collected from a total of 273 people who were working for a fashion company or working as an artist. Data was analyzed by the use of a frequency test, a reliability test, an exploratory factor analysis and a structure equation model analysis using AMOS 18.0. The results of the study were as follow. First, profitability and adequacy had significant effects, but awareness had no effect on confidence concerning the partnership. Second, awareness and profitability showed significant effects, but adequacy showed no effect on the flow among those in the partnership. Third, confidence had a significant effect on flow. Fourth, among the partnership factors, confidence and flow had significant effects on partnership satisfaction. Fifth, flow showed a significant effect on the intent for a continuous partnership, but confidence showed no effect.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1087-1098
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• 2019

In this paper, a detuning factor (DeFac) method is proposed to design the key parameters for optimizing the transfer power and efficiency of an Inductively Coupled Power Transfer (ICPT) system with primary-secondary side compensation. Depending on the robustness of the system, the DeFac method can guarantee the stability of the transfer power and efficiency of an ICPT system within a certain range of resistive-capacitive or resistive-inductive loads. A MATLAB-Simulink model of a ICPT system was built to assess the system's main evaluation criteria, namely its maximum power ratio (PR) and efficiency, in terms of different approaches. In addition, a magnetic field simulation model was built using Ansoft to specify the leakage flux and current density. Simulation results show that both the maximum PR and efficiency of the ICPT system can reach almost 70% despite the severe detuning imposed by the DeFac method. The system also exhibited low levels of leakage flux and a high current density. Experimental results confirmed the validity and feasibility of an ICPT system using DeFac-designed parameters.

• Wind and Structures
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• v.28 no.6
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• pp.381-388
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• 2019

This paper described the application of Geospatial Analysis in determining mean wind speed, $V_h$ for wind load calculation imposed to electrical transmission tower structural design. The basic wind speed data on available station obtained from Malaysian Meteorology Department is adjusted by considering terrain and ground roughness factor. The correlation between basic wind speed, terrain factor and ground roughness stated in EN-50341-1 is used to obtain the $V_h$ for overhead transmission line elements 50 m above ground. Terrain factor, $k_r$ and ground roughness, $z_0$ in this study are presented by land use types of study area. Wind load is then calculated by using equation stated in design code EN-50341-1 by using the adjusted mean wind speed. Scatter plots of $V_h$ for different $k_r$and $z_0$ are presented in this paper to see the effect of these parameters to the value of $V_h$. Geospatial analysis is used to represent the model of $V_h$. This model can be used to determine possible area that will subject to wind load which severe to the stability of transmission tower and transmission line.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.619-628
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• 2021

Enterprise system (ES) reflects a significant IT commitment to achieve corporate goals and satisfy its thrust toward a sustainable competitive advantage. This research investigates the required ES architecture, the value of a well-planned ES, and the human factor capabilities that drive the effective implementation of ES from a management perception. This paper examined the critical factors shaping the business systems' performance, architecture readiness, experts' readiness, and enterprise systems planning. Based on an extensive literature review, the attributes of factors mentioned earlier were identified, classified and then statistically examined using the author's' proposed conceptual structural model. This study employs a quantitative research methodology, with a random sampling technique. This paper has used the data collected from 510 respondents working in service, engineering and health sectors in OMAN. The study model analysis utilized both exploratory and confirmatory factor analysis, followed by a structural equation modeling using SPSS 25 and EQS6.3 statistical tools. The results unveil a piece of remarkable and robust evidence suggesting that ES planning is the most significant aspect of influencing performance, followed by IT personnel, staff and consumers expertise, and architecture readiness.