• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.427-434
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• 2000

The paper proposes a zero speed start-up scheme of direct rector controlled induction motor drive without any torque jerk. At standstill condition, a method is derived to calculate a stator flux with only stator current. The programmable 3-stage low pass filters with programmable time constants is used in order to solute the problem of integration for stator flux estimation in the direct vector control mode. Due to the time delay of 3-stage low pass filter, the status flux decreases rapidly and also the torque jerk occurs during the transition from standstill mode to the direct rector control mode. A feedforward control strategy of the stator flux is suggested to prevent the torque jerk at start-up. Through results of simulation and experiment with 32 bit DSP, the performance of the start-up scheme is verified.

• Smart Structures and Systems
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• v.20 no.2
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• pp.207-217
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• 2017

Because of the inevitable uncertainties such as structural parameters, external excitations and measurement noises, the effects of uncertainties should be taken into consideration in structural damage detection. In this paper, two probabilistic structural damage detection approaches are proposed to account for the underlying uncertainties in structural parameters and external excitation. The first approach adopts the statistical moment-based structural damage detection (SMBDD) algorithm together with the sensitivity analysis of the damage vector to the uncertain parameters. The approach takes the advantage of the strength SMBDD, so it is robust to measurement noise. However, it requests the number of measured responses is not less than that of unknown structural parameters. To reduce the number of measurements requested by the SMBDD algorithm, another probabilistic structural damage detection approach is proposed. It is based on the integration of structural damage detection using temporal moments in each time segment of measured response time history with the sensitivity analysis of the damage vector to the uncertain parameters. In both approaches, probability distribution of damage vector is estimated from those of uncertain parameters based on stochastic finite element model updating and probabilistic propagation. By comparing the two probability distribution characteristics for the undamaged and damaged models, probability of damage existence and damage extent at structural element level can be detected. Some numerical examples are used to demonstrate the performances of the two proposed approaches, respectively.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.8
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• pp.89-97
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• 2022

The e-commerce market faces significant credit risks due to the complexity of the industry and information asymmetries. Therefore, credit risk has started to stymie the growth of e-commerce. However, there is no reliable system for evaluating the creditworthiness of e-commerce companies. Therefore, this paper constructs a credit risk evaluation index system that comprehensively considers the online and offline behavior of online retail enterprises, including 15 indicators that reflect online credit risk and 15 indicators that reflect offline credit risk. This paper establishes an integration method based on a fuzzy integral support vector machine, which takes the factor analysis results of the credit risk evaluation index system of online retail enterprises as the input and the credit risk evaluation results of online retail enterprises as the output. The classification results of each sub-classifier and the importance of each sub-classifier decision to the final decision have been taken into account in this method. Select the sample data of 1500 online retail loan customers from a bank to test the model. The empirical results demonstrate that the proposed method outperforms a single SVM and traditional SVMs aggregation technique via majority voting in terms of classification accuracy, which provides a basis for banks to establish a reliable evaluation system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.53-60
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• 2009

Due to increased integration density and reduced threshold voltages, leakage current reduction becomes important in the semiconductor IC design for low power consumption. In a combinational logic circuit, the leakage current in the standby state depends on the values of the input. In this research, we developed a new input vector control method to minimize the leakage power. A new efficient algorithm is developed to find the minimal leakage vector. It can reduce the leakage current by 15.7% from the average leakage current and by 6.7% from the results of simulated evolution method during standby or idle states for a set of benchmark circuits. The minimal leakage input vector, with idle input signal, can also reduce the leakage current by 6.8% from the average leakage current and by 3.2% from the results of simulated evolution method for sequential circuits.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1243-1250
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• 1995

For the numerical solution of frictional dynamic contact problems, correct contact points and displacements are determined by iteratively reducing the displacement error vector monotonically toward zero And spurious oscillations are prevented from the solution by enforcing the velocity and acceleration compatibilities of the contact points with the corresponding error vectors. Numerical simulations are conducted to demonstrate the accuracy of the solution and the necessity of the velocity and acceleration compatibilities on the contact surface.

• Journal of the Korean Mathematical Society
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• v.49 no.1
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• pp.99-112
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• 2012

This paper attempts to present a numerical method for solving optimal control problems. The method is based upon constructing the n-th degree Jacobi polynomials to approximate the control vector and use differentiation matrix to approximate derivative term in the state system. The system dynamics are then converted into system of algebraic equations and hence the optimal control problem is reduced to constrained optimization problem. Numerical examples illustrate the robustness, accuracy and efficiency of the proposed method.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.243.1-243
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• 2000

No Abstract, See Full Text

• 대한생식의학회:학술대회논문집
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• 1999.11a
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• pp.71.2-72
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• 1999

• The Korean Journal of Mycology
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• v.25 no.3 s.82
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• pp.191-201
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• 1997

A mutant (HSMl) of Cryphonectria parasitica created during transformation reproduced the hypovirulent symptoms in virus-free wild type. Its phenomena have been proved with morphological marker such as reduced sporulation, pigmentation, and laccase production. In addition to the changes in phenotypic characteristics, down-regulations of Lac1, Crp1, Vir1 and Vir2 were also observed. The integration of transforming vector was confirmed and located within genome by marker rescuing. Vector integration occurred between two genes, Cpg2 and Cpg3, which resulted in the disruption of neither Cpg2 nor Cpg3. Both Cpg2 and Cpg3 genes, sized at 1.8 kb and 1.9 kb respectively, were rarely transcribed genes in Cryphonectria parasitica. Cpg2 expression was significantly overexpressed from 4 to 5 day old culture of both UEP1 and HSM1 while no differences were observed in Cpg3 expression. It appears that an aberration from the normal expression of Cpg2, not Cpg3, results in the hypovirulent symptoms in virus-free wild type.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.450-457
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• 1998

The cryparin of Cryphonectria parasitica belongs to a cell wall associated fungal hydrophobin. The cryparin, though it is encoded by a single copy gene, is known for the high expression during the liquid culture of C. parasitica, and it turns out that 22% of total mRNA was transcribed for cryparin at 48hr after the liquid culture. In addition, it is also known as one of down-regulated fungal proteins by the presence of double stranded RNA virus, Cryphonectria hypovirus 1. In previous studies (Kim et al., 1999), we have constructed a cryparin-null mutant by replacing the cryparin gene with hygromycin B resistance gene due to site directed homologous recombination. In order for the promoter analysis of cryparin which seems to be very strong as well as mycoviral specific, it is preferable to have a strain with only a target promoter replaced and a discernable target site for incoming vectors. However, the cryparin-null mutant revealed the presence of an additional copy of transforming vector except the one which replaced the cryparin gene. In addition, the cryparin-null mutant did not contain any markers for targeted integration of incoming vectors. This prompts us to design an experiment to obtain a strain for promoter analysis of cryparin gene. A different mating type strain EP6(Mata, $met^-$) was mated with the cryparin-null mutant ${\triangle}$Crp194-7(MatA, Crp${\triangle}$::hph) to make the progenies with only a single replacement vector and $met^-$ characteristic remained. Nutritional assay as well as Southern blot analysis revealed that the progeny, ${\triangle}$Crp194-a6, was the methionine auxotroph with a single replacing vector in genome. Northern blot analysis and PAGE showed that there was no cryparin produced in this bred strain either.