• Smart Structures and Systems
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• v.29 no.4
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• pp.549-560
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• 2022

The optimum damping and tuning frequency ratio of the tuned mass damper-inerter (TMDI) for the base-isolated structure is obtained using the numerical searching technique under stationary white-noise and filtered white-noise earthquake excitation. The minimization of the isolated structure's mean-square relative displacement and absolute acceleration, as well as the maximization of the energy dissipation index, were chosen as the criteria for optimality. Using a curve-fitting technique, explicit formulae for TMDI damping and tuning frequency for white-noise excitation are then derived. The proposed empirical expressions for TMDI parameters are found to have a negligible error, making them useful for the effective design of base-isolated structures. The effectiveness of TMDI and its optimum parameters are influenced by the soil condition and isolation frequency, according to the comparison made of the optimized parameters and response with different soil profiles. The effectiveness of an optimally designed TMDI in controlling the displacement and acceleration response of the flexible isolated structure under real and pulse-type earthquakes is also observed and found to be increased as the inertance mass ratio increases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.12
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• pp.1391-1400
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• 1992

In this paper, we suggested a method for evaluating the type-I/II error which is proposed by the CCITT as a criterion for the accuracy of policing algorithms in ATM networks, By the analysis of the type-I/II error of the Leaky Bucket(LB) algorithm, we investigated the relationships between the traffic parameters and the LB parameters to police the mean and peak cell rate effectively in the ON/OFF traffic. We showed that the LB parameters, the leaky rate a and the threshold M of the LB counter, could be determined as a pair of (a, M) satisfying the type-I/II error and minimizing the response time. In the ON/OFF traffic, it has been observed that the a-M characteristic curve of the LB policing algorithm only depends on the burstiness. As the results of the performance analysis, we found that the LB algorithm exhibits a good performance in the peak rate policing, but has some problems in the mean rate policing due to the trade-off between the accuracy and the response time.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.5
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• pp.423-430
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• 2012

An adaptive maximum power point tracking (MPPT) scheme employing a variable scaling factor is presented. A MPPT control loop was constructed analytically and the magnitude variation in the MPPT loop gain according to the operating point of the PV array was identified due to the nonlinear characteristics of the PV array output. To make the crossover frequency of the MPPT loop gain consistent, the variable scaling factor was determined using an approximate curve-fitted polynomial equation about linear expression of the error. Therefore, a desirable dynamic response and the stability of the MPPT scheme were maintained across the entire MPPT voltage range. The simulation and experimental results obtained from a 3 KW rated prototype demonstrated the effectiveness of the proposed MPPT scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6027-6033
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• 2012

In this paper, we proposed to model identification in frequency domain using relay feedback and Design of internal model controller(IMC) with Cascade controller. The parameters of controller in the inner loop are determined to minimize the integral of time multiplied by the absolute value of error (ITAE) value of performance Index. The controller of outer loop and parameters of IMC-PID controller can be obtain using identified model. The model identification is considered that it is the transient response and the steady-state response through the use of nyquist curve. Simulation examples are given to show the better performance of the proposed method than conventional methods.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.897-905
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• 2006

This study considers an experimental design of disturbance compensation control to improve stabilization performance of main battle tanks. An adaptive non-parametric design technique based on the Filtered-x Least Mean Square(FXLMS) algorithm is applied in the consideration of model uncertainties. The optimal compensator is designed by two-step design procedures: determination of frequency response function of the disturbance compensator which can cancel the disturbance of series of single harmonics by using the FXLMS algorithm and determination of the compensator polynomial which can fit the frequency response function obtained in the first step optimally by using a curve fitting technique. The disturbance compensator is applied to a simple experimental gun-torsion bar-motor system which simulates gun driving servo-system. Along with experimental results, the feasibility of the proposed technique is illustrated. Experimental results demonstrate that the proposed control reduces the standard deviation of stabilization error to 47.6% that by feedback control alone. The directional properties of the FXLMS Algorithm such as the direction of convergence and its convergence speed are also verified experimentally.

• Analytical Science and Technology
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• v.8 no.3
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• pp.335-340
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• 1995

Automatic biochemical oxygen demand(BOD) measurement system has heen developed using a microbial membrane electrode, prepared from Bacillus subtilis and polyvinyl alcohol(PVA). The automatic BOD measurement system showed a linear response curve up to BOD 60 ppm using a glucose/glutamic acid standard solution, and all the BOD measurement processes are carried out automatically to calculate BOD whithin 10 min after each sample injection. The response times of the microbial electrode was 5 minutes with a 5 min recovery time between measurements and the relative error of the BOD estimation was within 10%.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.115-118
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• 2004

We have examined the feasibility of using the specific interaction between mistletoe lectin I (ML I) and ${\beta}$-Dgalactose instead of the anti-ML I antibody in developing a homogeneous type competitive binding assay for ML I. We also have examined the feasibility of adapting the biotin/avidin mediated homogeneous assay for this system. Alkaline phosphatase (AKP) was employed as a single substrate enzyme label. The dose-response curve shows a detection range of 1-25 ${\mu}$g/mL and a linear response with a correlation coefficient of 0.99. To demonstrate the analytical utility of this method, 10 ${\mu}$g/mL of ML I was spiked into distilled water. The results show that the mean recovery was 10.03 ${\mu}$g/mL with an SD of 0.18. The difference between the spiked value and the mean recovery was 0.03 ${\mu}$g/mL, with a relative error of 0.3 and 1.6 % of RSD.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.269-275
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• 2019

This study intended to examine the relationship between inflation and unemployment rate in Indonesia during 1987 to 2018 period. The study applied a quantitative method using Vector Error Correction Model (VECM) in order to comprehensively understand the causality between inflation and unemployment rates. The data were collected from various main sources including the World Bank, Central Bank of Indonesia, and Central Bureau of Statistics (BPS). The findings showed that inflation has a one-way relationship toward unemployment in Indonesia and it occurs at the third lag. Impulse Response Function (IRF), shows that the inflation rate are fluctuating in response to the shock of unemployment. The unemployment rate responses to shocks from inflation initially increased until it is eventually diminished. It shows that the shocks caused by the impact of inflation were only in the short term. Further, inflation in the three previous lags will have consequences for the unemployment rate in the year. Lastly, both in the long run and short run, unemployment did not affect inflation rates. These findings suggest that high inflation in Indonesia is determined the rising price of basic commodities and fuel. In addition, most companies in Indonesia applying capital intensive so that employment growth in Indonesia is small.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.53-60
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• 2002

It has been recognized that damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the inelastic response is required. The methods available to the design engineer today are nonlinear time history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. Some codes proposed the capacity spectrum method based on the nonlinear static(pushover) analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method to evaluate seismic Performance of structure, without iterative computations, given the structural initial elastic period and yield strength from the pushover analysis, especially for multi degree of freedom structures. The purpose of this paper is to investigate accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters.

• Earthquakes and Structures
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• v.2 no.1
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• pp.25-42
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• 2011

This paper discusses a mechanical model for the vulnerability assessment of old masonry building aggregates that takes into account the uncertainties inherent to the building parameters, to the seismic demand and to the model error. The structural capacity is represented as an analytical function of a selected number of geometrical and mechanical parameters. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the capacity curve are obtained as a function of the statistical moments of the input parameters, showing the role of each one in the overall capacity definition. The seismic demand is represented by response spectra; vulnerability analysis is carried out with respect to a certain number of random limit states. Fragility curves are derived taking into account the uncertainties of each quantity involved.