• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.8
• /
• pp.914-921
• /
• 1992

In this paper, we introduce a Walsh network and an LMS algorithm, and show how these can be realized as an adaptive equalizer. The Walsh network is built from a set of Walsh and Block pulse functions. In the LMS algorithm, the convergence factor is an important design parameter because it governs stability and convergence speed, which depend on the proper choice of the convergence facotr. The conventional adaptation techniques use a fixed time constant convergence factor by the method of trial and error. In this paper, we propose an optimal method in the choice of the convergence factor. The proposed algorithm depends on the received signal and the output of the Walsh network in real time.

• Kyungpook Mathematical Journal
• /
• v.60 no.4
• /
• pp.869-881
• /
• 2020

Most first kind integral equations are ill-posed, and obtaining their numerical solution often requires solving a linear system of algebraic equations of large condition number, which may be difficult or impossible. This article proposes a regularization-direct method to numerically solve first kind Fredholm integral equations. The vector forms of block-pulse functions and related properties are applied to formulate the direct method and reduce the integral equation to a linear system of algebraic equations. We include a regularization scheme to overcome the ill-posedness of integral equation and obtain a stable numerical solution. Some test problems are solved using the proposed regularization-direct method to illustrate its efficiency for solving first kind Fredholm integral equations.

• Structural Engineering and Mechanics
• /
• v.67 no.4
• /
• pp.359-368
• /
• 2018

In this paper, a method is presented to identify the physical and modal parameters of multistory shear building based on substructural technique using block pulse generalized operational matrix and genetic algorithm. The substructure approach divides a complete structure into several substructures in order to significantly reduce the number of unknown parameters for each substructure so that identification processes can be independently conducted on each substructure. Block pulse functions are set of orthogonal functions that have been used in recent years as useful tools in signal characterization. Assuming that the input-outputs data of the system are known, their original BP coefficients can be calculated using numerical method. By using generalized BP operational matrices, substructural dynamic vibration equations can be converted into algebraic equations and based on BP coefficient for each story can be estimated. A cost function can be defined for each story based on original and estimated BP coefficients and physical parameters such as mass, stiffness and damping can be obtained by minimizing cost functions with genetic algorithm. Then, the modal parameters can be computed based on physical parameters. This method does not require that all floors are equipped with sensor simultaneously. To prove the validity, numerical simulation of a shear building excited by two different normally distributed random signals is presented. To evaluate the noise effect, measurement random white noise is added to the noise-free structural responses. The results reveal the proposed method can be beneficial in structural identification with less computational expenses and high accuracy.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.556-558
• /
• 1990

A method of model reduction for reducing a higher order Z-transfer function to its lower order model is developed based on the Block - pulse function. The approach is following : I. Block - pulse function can be applied for Z-transfer function of linear digital system described by high order. II. To determined both the coefficients of the denominator and numerator of reduced model. The proposed method is simple for computation, can preserve the dynamic characteristic of the original model satisfactorily.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.605-609
• /
• 2000

This paper presents a development of the Pulse Width Modulation ASIC for control of the AC servo or spindle motor in machine tools. The ASIC is designed two PWM functions for simultaneous control of a converter and an inverter. Also the device includes additionally two UART functions for interfacing the RS232C with PC or other devices. The device is connected to the microprocessor of Intel or Motorola by bus interface. The required output voltage and frequency for the motor control is programmed to the PWM block and the corresponding switching signals are calculated and generated with regard to the programmed value.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2543-2545
• /
• 2005

It is well known that the orthogonal function is a very useful to estimate an unknown inputs in the linear dynamic systems for its recursive algebraic algorithm. At this aspects, derivative operation(matrix) of orthogonal functions(walsh, block pulse and haar) are introduced and shown how it can useful to design an UIO(unknown inputs observer) design.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.5
• /
• pp.354-360
• /
• 2003

For the convenient use of high performance microprocessor in motor control, peripheral devices are needed for converting its control signals to compatible ones for motor drive. Customized devices are not plentiful far these purposes and their functions do not usually satisfied designers specification. The designers used to implement these functions on FPGA or CPLD using hardware description language. Then, in this case unessential programs are needed for control the peripherals. In this paper, a unified device model that links peripheral devices, including especially the pulse width modulation controller and the quadrature encoder interface device, to an interrupt controller is proposed. Advanced functions of peripherals could be achieved by this model and unessential programs can be simplified. Block diagrams and flowcharts are presented to illustrate the advanced functions. This unified device was designed using VHDL. The simulation results were presented to demonstrate the effectiveness of the proposed scheme.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.6
• /
• pp.598-606
• /
• 1990

Common problems encountered when orthogonal functions are used in system analysis and state estimation are the time consuming process of high order matrix inversion required in finding the Kronecker products and the truncation errors. In this paper, therefore, a method for the analysis of bilinear systems using Walsh, Block pulse, and Haar functions is devised, Then, state estimation of bilinear system is also studied based on single term expansion of orthogonal functions. From the method presented here, when compared to the other conventional methods, we can obtain the results with simpler computation as the number of interval increases, and the results approach the original function faster even at randomly chosen points regardless of the definition of intervals. In addition, this method requires neither the inversion of large matrices on obtaining the expansion coefficients nor the cumbersome procedures in finding Kronecker products. Thus, both the computing time and required memory size can be significantly reduced.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.410-412
• /
• 1998

Some resent papers deals with the solution of LTI singular systems described in state-space via orthogonal functions. There are some complexity to derive the solution because all the previous works[2]-[5] used orthogonal function's integral operation. Therefore, in this paper, some new results are introduced by using a differential operation of orthogonal function to solve the LTI singular systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.1066-1070
• /
• 1990

This paper presents a method for the optimal control of the distributed parameter systems (DPSs) by a hierarehical computational procedure. Approximate lumped parameter systems (LPSs) are derived by using the Galerkin method employing the Legendre polynomials as the basis functions. The DPSs however, are transformed into the large scale LPSs. And thus, the hierarchical control scheme is introduced to determine the optimal control inputs for the obtained LPSs. In addition, an approach to block pulse functions is applied to solve the optimal control problems of the obtained LPSs. The proposed method is simple and efficient in computation for the optimal control of DPSs.