• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.4
• /
• pp.282-290
• /
• 2000

In this paper, the charge control with the input voltage feedback is proposed for the input series-output series-output parallel connected converter configuration for the high speed train power system application. This control scheme accomplishes the output current sharing for the output-parallel connected modules as well as the input voltage sharing for the input series connected modules for all operating conditions including the transients. It also offers the robustness for the input voltage sharing control according to the component value mismatches among the modules. And this configuration enables the usage of MOSFET for a high voltage system allowing a higher switching frequency for lighter system weight and smaller size. The performance of the proposed scheme is verified through the experimental results.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.285-288
• /
• 1998

A least-squares identification method is studied that estimates a finite number of coefficients in the series expansion of a transfer function, where the expansion is in terms of recently introduced generalized basis functions, We will expand and generalize the orthogonal functions as basis functions for dynamical system representations. To this end, use is made of balanced realizations as inner transfer functions. The orthogonal functions can be considered as generalizations of, for example, the pulse functions, Laguerre functions, and Kautz functions, and give rise to an alternative series expansion of rational transfer functions. We show that the Laplace transform of the expansion for some sets$\Psi_{\kappa}(Z)$ is equivalent to a series expansion . Techniques based on this result are presented for obtaining the coefficients $c_{n}$ as those of a series. One of their important properties is that, if chosen properly, they can substantially increase the speed of convergence of the series expansion. This leads to accurate approximate models with only a few coefficients to be estimated. The set of Kautz functions is discussed in detail and, using the power-series equivalence, the truncation error is obtained.

• Journal of Internet of Things and Convergence
• /
• v.4 no.1
• /
• pp.1-5
• /
• 2018

This paper is concerned with the modeling and identification of time series data corrupted by noise. As modeling techniques, nonsingleton fuzzy logic system (NFLS) is employed for the modeling of corrupted time series. Main characteristic of the NFLS is a fuzzy system whose inputs are modeled as fuzzy number. So the NFLS is especially useful in cases where the available training data or the input data to the fuzzy logic system are corrupted by noise. Simulation results of the Mackey-Glass time series data will be demonstrated to show the performance of the modeling methods. As a result, NFLS does a much better job of modeling noisy time series data than does a traditional Mamdani FLS.

• Journal of Radiation Protection and Research
• /
• v.23 no.3
• /
• pp.197-210
• /
• 1998

Regulations for the safe transport of radioactive material published by IAEA Safety Standard Series ST-l is reviewed and summarized. Safety Series No.115(International standard of radiation protection and safety for ionizing radiation and radiation sources), which reflected the new recommendation of ICRP60 published in 1991, has been a important encouragement for IAEA to revise their safety series related to the transportation of radioactive materials. IAEA Safety, Standard Series No. ST-l is summarized by comparing IAEA Safety Series No.6 regarding radiation protection system and its implementation, technical standards of packages, concept of Q system and exemption of regulation. The IAEA regulations of transportation of radioactive materials is summarized from the viewpoint of radiation protection and safety assessment. Research on transportation system of radioactive waste is suggested as a further study.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.3
• /
• pp.461-465
• /
• 2005

Characteristics of biological $CO_2$ fixation by Chlorella sp. HA-1 were investigated in a semi-continuous and series reactor system using an internally illuminated photobioreactor to overcome shortcomings of physicochemical technologies such as adsorption and membrane separation. High $CO_2$ fixation rate was achieved in the semi-continuous reactor system, in which the dilution ratios of the culture medium were controlled. The average $CO_2$ fixation rate was maintained almost constantly when the dilution ratio increased by 0.1 increment from the initial value of 0.5. The total removal efficiency of $CO_2$ was enhanced by employing a series reactor system. The average $CO_2$ fixation rate increased until 4.013 g $CO_2\;day^{-1}$ in a series operation of four reactors, compared to 0.986 g $CO_2\;day^{-1}$ in a batch operation mode. The total $CO_2$ fixation rate was proportional to the number of reactors used in the series reactor system. In the series reactor system of semi-continuous operation, a large amount of $CO_2$ was removed continuously for 30 days. These results showed that the present reactor systems are efficient and economically feasible for a biological $CO_2$ fixation.

• Journal of Korean Society for Quality Management
• /
• v.24 no.4
• /
• pp.112-123
• /
• 1996

ISO 9000 series, as quality management system that assesses quality system based on the documentation such as quality manual, documented procedures, specification is properly operated and then decides to give a certification, is a screening documented system that includes factors which may influence quality. Therefore, to have a proper documented system and its performance accordant to it is very important to the company which hopes to acquire the certification of ISO 9000 series. So, the objectives of this paper are to increase the efficiency of the work by cutting down efforts necessary to establish and revise documented procedures for the certification of the ISO 9000 series in the company using the documentation system.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.87-89
• /
• 2005

This paper proposes new series and parallel Sin+Cos PSS(power system stabilizer) for the purpose to improve the existing PSS1A's performance. The purpose of PSS is used to enhance damping of power system oscillations through injection of auxiliary signal for an excitation control terminal. The Proposed series and Parallel Sin+Cos PSS is connected adding the Sin+Cos terms additionally with serial and with parallel connection in a conventional PSS1A. The proposed controller is aim to considering of a damping of oscillation when it changes parameter fluctuations or operational load variations in a power system. The object of electric power system is KEPCO system and the voltage of power transmission line is a 154kV and a 345kV. The PSCAD/EMTDC package is used to authorize the effect of the proposed controller. Simulations were shown by and compared with the waveforms for frequency, voltage and electric power.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.4 no.3
• /
• pp.361-365
• /
• 2004

In this paper, we present the modeling of time series data which are corrupted by noise via nonsingleton fuzzy logic system. Nonsingleton fuzzy logic system (NFLS) is useful in cases where the available data are corrupted by noise. NFLS is a fuzzy system whose inputs are modeled as fuzzy number. The abilities of NFLS to approximate arbitrary functions, and to effectively deal with noise and uncertainty, are used to analyze corrupted time series data. In the simulation results, we compare the results of the NFLS approach with the results of using only a traditional fuzzy logic system.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.5 no.3
• /
• pp.43-50
• /
• 2006

In this successive study, the analytical realization of coupled system was introduced using the times series identification and spectrum analysis, which was compared with conventional FFT spectrum. Also, the numerical responses of second order system, which is coupled, were solved using the numerical calculation of Runge-Kutta Gill method. After numerical analysis, the displacement, velocity and acceleration were acquired. Among them, the response of displacement was used for the analysis of time series spectrum. Among several time series, the ARMAX algorithm was proved to be appropriate for the spectrum analysis of the coupled system. Using the separated response of 1st and 2nd mode, the mode was calculated separately. And the responses of mixed modes were also analyzed for calculation of the mixed modes in the coupled system.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.7
• /
• pp.1396-1403
• /
• 2011

It is not easy to analyze the strong nonlinear time series and effectively design a good prediction system especially due to the difficulties in handling the potential uncertainty included in data and prediction method. To solve this problem, a new design method for fuzzy prediction system is suggested in this paper. The proposed method contains the followings as major parts ; the first-order difference detection to extract the stable information from the nonlinear characteristics of time series, the fuzzy rule generation based on the hierarchically classifying clustering technique to reduce incorrectness of the system parameter identification, and the IT2TSK fuzzy logic system to reasonably handle the potential uncertainty of the series. In addition, the design of the multiple predictors is considered to reflect sufficiently the diverse characteristics concealed in the series. Finally, computer simulations are performed to verify the performance and the effectiveness of the proposed prediction system.