• Proceedings of the KIEE Conference
• /
• 2002.11d
• /
• pp.313-316
• /
• 2002

In this paper, we present an online scheme for parameter estimation of solar cell, based on the model adjustment technique and a genetic algorithm. The ideal diode model and the diode model with series and shunt resistor are used to estimate their parameters. Simulation works using field data in the form of a VI characteristic curve are carried out to demonstrate the effectiveness of the proposed method.

• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.542-543
• /
• 2014

In this paper, an estimation scheme based on an augmented sigma-point Kalman filter to estimate the state of charge (SOC) of the battery is presented, where the battery parameters of the series resistance ($R_o$), diffusion capacitance ($C_1$) and resistance ($R_1$) are also estimated through the recursive least squares (RLS) for better accuracy of the SOC. The effectiveness of the proposed method is verified by simulation results.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.8 no.3
• /
• pp.80-87
• /
• 1998

This paper presents and online scheme for fuzzy modelling of nonlinear systems, based on the model adjustment technique and the genetic algorithm technique. The fuzzy model is characterized by fuzzy "if-then" rules which represent locally linear input-output relations whose consequence parts are defined as subsystems of a nonlinear sysem. The discrete-time model for each subsystem is obtained to deal with initalization and unmeasurable signal problems in online estimation and the final output of the fuzzy model is computed from the outputs of the discrete-time models. Then, the parameters of both the premise and consequence parts of the fuzzy model are adjusted by a genetic algorithm. A set of simulation works is carried out to demonstrate the effectiveness of the proposed method.ed method.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.391-393
• /
• 2007

The rotor speed and flux information is most important in the vector control. The accuracy of flux observers for induction machine inherently depends on parameter sensitivity. The control strategy is using online flux observer for flux estimation. In the proposed system, the speed control characteristics using a online flux observer control isn't affected by a load torque parameter disturbance. Simulation results are presented to prove the effectiveness of the adaptive sliding mode controller for the drive variable load of induction motor.

• Journal of Power Electronics
• /
• v.16 no.5
• /
• pp.1752-1762
• /
• 2016

To achieve higher reliability in the modular multilevel converters (MMC) for HVDC transmission systems, the internal condition of the DC capacitors of the submodules (SM) needs to be monitored regularly. For an online estimation of the SM capacitance, a controlled AC current with double the fundamental frequency is injected into the circulating current loop of the MMC, which results in current and voltage ripples in the SM capacitors. The capacitor currents are calculated from the arm currents and their switching states. By processing these AC voltage and current components with digital filters, their capacitances are estimated by a recursive least square (RLS) algorithm. The validity of the proposed scheme has been verified by simulation results for a 300-MW, 300-kV HVDC system. In addition, its feasibility has been verified by experimental results obtained with a reduced-scale prototype. It has been shown that the estimation errors for both the simulation and experimental tests are 1.32% at maximum.

• Journal of the Korean GEO-environmental Society
• /
• v.7 no.1
• /
• pp.67-80
• /
• 2006

This paper presented an application of the geotechnical hybrid-online simulation to the consolidation settlement problem of soft clay. Conventional numerical analyses have used idealized soil constitutive models obtained from the laboratory soil tests. On the other hand, in the hybrid-online simulation, soil response was directly introduced to numerical analyses from the soil element test, and, therefore, the complicated parameter estimation was not required in this method. Fundamentals of the hybrid-online simulation method and the development of the algorithm and corresponding hardware and software for the system were presented in this study. Furthermore, an incremental loading consolidation and the hydraulic conductivity test and a comparative study using the Terzagh's conventional consolidation theory were carried out for the system verification including the performance of the experimental device and source coding of software components, and the data reliability obtained from the system. In conclusion, we found that the hybrid-online consolidation simulation system could reproduce the consolidation behavior of the remolded Kaolinite specimen withoutany discrepancies.

• Journal of Power Electronics
• /
• v.16 no.5
• /
• pp.1981-1989
• /
• 2016

Battery diagnosis is vital to battery-based applications because it ensures system reliability by avoiding battery failure. This paper presents a novel intelligent battery charger with an online diagnosis function to circumvent interruptions in system operation. The charger operates in normal charging and diagnosing modes. The diagnosis function is performed with the impedance spectroscopy technique, which is achieved by injecting a sinusoidal voltage excitation signal to the battery terminals without the need for additional hardware. The impedance spectrum of the battery is calculated based on voltage excitation and current response with the aid of an embedded digital lock in amplifier in a digital signal processor. The measured impedance data are utilized in the application of the complex nonlinear least squares method to extract the battery parameters of the equivalent circuit. These parameters are then compared with the reference values to reach a diagnosis. A prototype of the proposed charger is applied to four valve-regulated lead-acid batteries to measure AC impedance. The results are discussed.

• International Journal of Computer Science & Network Security
• /
• v.22 no.9
• /
• pp.316-326
• /
• 2022

The prompt development in the field of video is the outbreak of online services which replaces the television media within a shorter period in gaining popularity. The online videos are encouraged more in use due to the captions displayed along with the scenes for better understandability. Not only entertainment media but other marketing companies and organizations are utilizing videos along with captions for their product promotions. The need for captions is enabled for its usage in many ways for hearing impaired and non-native people. Research is continued in an automatic display of the appropriate messages for the videos uploaded in shows, movies, educational videos, online classes, websites, etc. This paper focuses on two concerns namely the first part dealing with the machine learning method for preprocessing the videos into frames and resizing, the resized frames are classified into multiple actions after feature extraction. For the feature extraction statistical method, GLCM and Hu moments are used. The second part deals with the deep learning method where the CNN architecture is used to acquire the results. Finally both the results are compared to find the best accuracy where CNN proves to give top accuracy of 96.10% in classification.

• Journal of Distribution Science
• /
• v.20 no.6
• /
• pp.75-86
• /
• 2022

Purpose: This research aims to provide empirical evidence on the impact of digital literacy on behavioural intention regarding using technology for distribution of higher education. Design, Methodology, and Approach: Quantitative analysis was carried out using Covariance-Based Structural Equation Model with data collected from 901 students who fully experienced 2-year study online at different universities in Vietnam. The structural model was built with digital literacy as the primary indicator and other variables were included based on modified version of Unified Theory of Acceptance and Use of Technology (UTAUT2) by adopting performance expectancy, effort expectancy, social influence, habit, and hedonic motivation variables specifically for education sector. Self-efficacy was added to eliminate possible bias in technology acceptance. Results: From the results of model estimation, digital literacy presented positive impact on the online distribution of higher education in Vietnam. The mediating effects of various indicators such as performance expectancy, effort expectancy, social influence, habit, hedonic motivation, and self-efficacy are significantly determined by research model. Conclusion: The higher level of digital literacy of the students, the more likely that they will use technology in higher education study, especially online learning. Additionally, the mediating effects of indicators from the UTAUT2 theoretical model were also evident to be positively significant.

• International Commerce and Information Review
• /
• v.18 no.2
• /
• pp.27-51
• /
• 2016

The purpose of this paper is to examine correlations between the facilitating factors of the B2C e-commerce and the online shopping and the overseas direct purchase for the purpose of suggesting the successful logistics operational strategies for the domestic parcel delivery service companies. This paper conducts wide literature reviews and empirical analyses on relationships between the facilitating factors of B2C e-commerce and the online shopping and the overseas direct purchase in B2C e-commerce. We built two regression equations that dependable variables are the turnover of online shopping and the amount of imports by international postal logistics services respectively. The former equation's estimation results show that all the independable variables are affecting the dependable variable in the long-term jointly. And, the results show that the change of the turnover of online shopping is affected not only by the change of the usage count of a credit card and the real GDP, but also by the change of the error-correction variable. The latter equation's estimation results show that all the independable variables are affecting the dependable variable in the long-term jointly. Futhermore, the results show that the change of the amount of imports by international postal logistics services is affected not only by the change of the usage count of a credit card, the exchange rate and the internet protocol IPv4, but also by the change of the error-correction variable. Based on these research results, a high advanced strategic approach for optimum parcel delivery services is highly required.