• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.79-85
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• 2007

In this paper, a real-coded genetic algorithm is proposed for identification of time delay systems from step responses. FOPDT(First-Order Plus Dead-Time) and SOPDT(Second-Order Plus Dead-Time) systems, which are the most useful processes in this field, but are difficult for system identification because of a long dead-time problem and a model mismatch problem. Genetic algorithms have been successfully applied to a variety of complex optimization problems where other techniques have often failed. Thus, the modified crossover operator of a real-code genetic algorithm is proposed to effectively search the system parameters. The proposed method, using a real-coding genetic algorithm, shows better performance characteristics when compared to the usual area-based identification method and the directed identification method that uses step responses.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.597-605
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• 2010

This paper presents a contribution to parameter identification of a non-linear system using a new strategy to improve the genetic algorithm (GA) method. Since cost function plays an important role in GA-based parameter identification, we propose to improve the simple version of GA, where weights of the cost function are not taken as constant values, but varying along the procedure of parameter identification. This modified version of GA is applied to the induction motor (IM) as an example of nonlinear system. The GA cost function is the weighted sum of stator current and rotor speed errors between the plant and the model of induction motor. Simulation results show that the identification method based on improved GA is feasible and gives high precision.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1065-1073
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• 2002

A new damage identification technique using static displacement data is developed to assess the structural integrity of bridge structures. In the conventional damage assessment techniques using dynamic response, it is usually difficult to obtain a significant natural frequencies variation from the measured data because the natural frequencies variation is intrinsically not sensitive to the damage of a bridge. In this proposed identification method, the stiffness reduction of the bridges can be estimated using the static displacement data measured periodically and a specific loading test is not required. The static displacement data due to the dead load of the bridge structure can be measured by devices such as a laser displacement sensor. In this study, structural damage is represented by the reduction in the elastic modulus of the element. The damage factor of the element is introduced to estimate the stiffness reduction of the bridge under consideration. Finally, the proposed algorithm is verified using various numerical simulation and compared with other damage identification method. Also, the effect of noise and number of damaged elements on the identification are investigated. The results show that the proposed algorithm is efficient for damage identification of the bridges.

• Smart Structures and Systems
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• 제15권1호
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• pp.81-97
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• 2015

Recently, a new output-only modal identification method based on time-frequency independent component analysis (ICA) has been developed by the authors and shown to be useful for even highly-damped structures. In many cases, it is of interest to identify the complex modes of structures with non-proportional damping. This study extends the time-frequency ICA based method to a complex ICA formulation for output-only modal identification of non-proportionally-damped structures. The connection is established between complex ICA model and the complex-valued modal expansion with sparse time-frequency representation, thereby blindly separating the measured structural responses into the complex mode matrix and complex-valued modal responses. Numerical simulation on a non-proportionally-damped system, laboratory experiment on a highly-damped three-story frame, and a real-world highly-damped base-isolated structure identification example demonstrate the capability of the time-frequency complex ICA method for identification of structures with complex modes in a straightforward and efficient manner.

• 한국의류학회지
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• 제34권5호
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• pp.797-807
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• 2010

This study investigates the effects of consumer brand identification and brand attachment to brand equity. 332 surveys were collected from male and female university students in Seoul. In each survey, respondents were asked to choose one favorite fashion brand that they often purchase and answer questions regarding brand identification, brand attachment, and brand equity. The results were analyzed using SPSS package 12.0 and AMOS 5.0 program and factor analysis, reliability analysis, and path analysis were conducted. After the factor analysis, 3 factors were found under brand identification, 4 factors under brand attachment, and 4 factors under brand equity. The Cronbach's $\alpha$ of brand identification was .84, the brand attachment was .80, and the brand equity was .81. The results of this study show that brand identification had a positive effect on brand attachment that had a positive effect on brand equity. Additional results show that both brand identification and brand attachment had a positive direct effect on brand equity; however, brand attachment had a higher effect on brand equity.

• Smart Structures and Systems
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• 제15권1호
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• pp.57-80
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• 2015

Extended Kalman Filter (EKF) has been widely used for structural identification and damage detection. However, conventional EKF approaches require that external excitations are measured. Also, in the conventional EKF, unknown structural parameters are included as an augmented vector in forming the extended state vector. Hence the sizes of extended state vector and state equation are quite large, which suffers from not only large computational effort but also convergence problem for the identification of a large number of unknown parameters. Moreover, such approaches are not suitable for intelligent structural damage detection due to the limited computational power and storage capacities of smart sensors. In this paper, a two-stage and two-step algorithm is proposed for the identification of structural damage as well as unknown external excitations. In stage-one, structural state vector and unknown structural parameters are recursively estimated in a two-step Kalman estimator approach. Then, the unknown external excitations are estimated sequentially by least-squares estimation in stage-two. Therefore, the number of unknown variables to be estimated in each step is reduced and the identification of structural system and unknown excitation are conducted sequentially, which simplify the identification problem and reduces computational efforts significantly. Both numerical simulation examples and lab experimental tests are used to validate the proposed algorithm for the identification of structural damage as well as unknown excitations for structural health monitoring.

• 사상체질의학회지
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• 제32권3호
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• pp.18-32
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• 2020

Objectives In order to find out the relationship between the Eight Principle Pattern Identification of Cold-Heat, Deficiency-Excess and the Sasang constitution, we analyzed the clinical data from 500 women with menstrual pain and women without menstrual pain. Methods In the previous study, the subject's information of Typology Complexion Pulse and Symptom was collected, and Eight Principle Pattern Identification was executed based on this. Later, the relationship between the Sasang constitution and the Eight Principle Pattern Identification was statistically analyzed. Results and Conclusion 1. The obvious difference between the experimental group and the control group in the patterns of Cold-Heat and Deficiency-Excess is that patients who complain of menstrual pain do not maintain harmony with the yin-yang ratio, it can be said that the patterns of Cold-Heat and Deficiency-Excess can be a Identification standard that significantly obscures the condition of the disease. 2. There was a significant difference between the Sasang constitution and the Eight Principle Pattern Identification of Cold-Heat. There was no significant difference between the Sasang constitution and the Eight Principle Pattern Identification of Deficiency-Excess.

• International Journal of Advanced Culture Technology
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• 제8권4호
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• pp.39-50
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• 2020

The current number of international students is gradually increasing in the world due to their passion for study or exchange students programs related to be affiliated with their universities. Many international students have great hope for their successful life of studying abroad. The factors that play a key role in successful study abroad can be seen as life satisfaction in host country and career commitment. Therefore, this study suggested the way to improve students' life satisfaction and career commitment among Chinese international students in Korea. It focused on social identification as a core factor in improving international student life satisfaction and career commitment. In addition, it also focused on social support as a factor to increase social identification. According to the results of empirical analysis, it was verified that perceived social support improves social identification among international students. In addition, social identification improves their life satisfaction and career commitment. Therefore, the mediating effect of social identification was found to be significant in the relationship between perceived social support and life satisfaction and career commitment. This study was verified that if international students perceive social support, they can experience social identification. This process can eventually lead to life satisfaction and career commitment. Based on these results, it emphasized that the role and importance of social identification. Finally, the practical implications and future research directions were discussed.

• 로봇학회논문지
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• 제7권3호
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• pp.222-230
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• 2012

The paper presents a momentum-based regressor by using Hamiltonian dynamics representation for robotic manipulator. It has an advantage in that the proposed regressor does not require the acceleration measurement for the identification of dynamic parameters. Also, the identification algorithm is newly suggested by solving a minimization problem with constraint. The developed algorithm is easy to implement in real-time. Finally, the effectiveness of the proposed momentum-based regressor and identification method is shown through numerical simulations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.121-126
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• 2004

In this paper, a nonlinear structural damage identification algorithm is derived by taking into account the structurally damped spectral element model thinking over a real situation. The structural damage identification analyses are conducted by using the Newton-Raphson method. It is found that, in general Structural Damage Identification by using the Structurally Damped Spectral Element Model provides the same exact damage identification results when compared with the results obtained by the structurally undamped spectral model.