KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Start date: 1980End date: 1999

Search Results

Now showing 1 - 10 of 230
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    SAR images speckle noise reduction by wavelet thresholding
    (1999-12-01)
    Thitimajshima, Punya
    This paper describes a method of speckle reduction in Synthetic Aperture Radar (SAR) images based on the wavelet transform. To deduce the problem of filtering the multiplicative noise to the case of an additive noise, the wavelet decomposition is performed on the logarithm of the image gray levels. A threshold value is estimated according to the noise variance and used for the soft-thresholding performed on all the high frequency subimages. The filtered logarithmic image is then obtained by reconstruction from the thresholded coefficients. The exponential function of this reconstructed image gives the final filtered image. Experimental results on JERS-1/SAR images showed that the proposed method results in a significant noise removal.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Adaptive fuzzy PI controller for speed of separately excited DC motor
    (1999-12-01)
    Tunyasrirut, S.
    ;
    Ngamwiwit, J.
    ;
    Furuya, T.
    This paper presents a design of adaptive fuzzy PI controller to control the speed of separately excited DC motor by self-tuning. The speed of motor can be changed by controlling the armature and field voltages. In this paper, the adaptive fuzzy PI controller is designed to control the armature voltage while the field voltage is fixed as a constant. The fuzzy system tunes the gains of the PI controller according to error and change of error of the speed control system to meet the step response specifications of the motor speed. The experimental results show that the step responses of the speed of the DC motor controlled by the adaptive fuzzy PI controller have step responses with small overshoot when compared to the usual PI cascade controller. That is, the proposed controller gives the controlled system has small overshoot and zero steady-state error when the reference speed is 2000 rpm at no load, half load and full load. The effect of the applied step full load and released load at the steady state is also rapidly rejected.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    BRM technique for space vector decomposition reactive power of SPIM
    (1999-12-01)
    Tipsuwanporn, V.
    ;
    Cheevasuvit, F.
    This research paper proposes the controlling technique of Single Phase Induction Motor (SPIM) by Binary Rate Modulation (BRM). The BRM composes of 8 independent patterns, these patterns can be linearly combined into 255 pattern forms, then transmit to control motor speed. Applying this technique along with vector space will result in power factor increasing and reactive power decreasing. When load is at threshold state it can be brought to the steady state condition at short instant, consequently the capacity and efficiency will be improved.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Temperature-insensitive voltage-to-current converter and its applications
    (1999-12-01)
    Surakampontorn, Wanlop
    A novel voltage-to-current (V/I) converter circuit is proposed, which is based on an Operational Transconductance Amplifier (OTA) integrated circuit. The V/I transconductance gain is insensitive to temperature and the input differential voltage swing limitation of the OTA integrated circuit is alleviated. New circuits for the temperature-insensitive general-grounded resistance converter, instrumentation amplifier, electronically tunable gyrator, and analog multiplier are presented. Experimental and simulation results that demonstrate the performances of the V/I and its applications are also included.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Analysis of steerable active slot array applicator
    (1999-12-01)
    Krairiksh, M.
    ;
    Thongsopa, C.
    ;
    Srimoon, D.
    ;
    Mearnchu, A.
    This paper analyzes temperature distribution of a steerable active slot array applicator in terms of slot separation and injecting signal to find the appropriate condition that provides a wide effective area. This result is useful in the design of an applicator for a large area application such as chest wall.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    BRM fast response DC motor speed control
    (1999-12-01)
    Tipsuwanporn, V.
    ;
    Cheevasuvit, F.
    ;
    Piyarat, W.
    ;
    Siribanchachai, W.
    ;
    Paraken, Y.
    The paper presents, hithtero contribute the DC motor control by Binary Rate Modulation (BRM). The 8 bit binary rate are controlled by 8051 which inturn generate BRM by PI(Proportional Integral Controller). The BRM method is efficient to control the supplied power with appropriate speed. BRM method has low ripple, usually less than 5%, consequently, less noise with fast speed response when load changes.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Fuzzy logic control for speed of wound rotor induction motor with slip energy recovery
    (1999-12-01)
    Tunyasrirut, Satean
    ;
    Kanchanathep, Attapol
    ;
    Ngamwiwit, Jongkol
    ;
    Furuya, Tadayoshi
    Fuzzy Logic control is considered for speed of wound rotor induction motors with slip energy recovery. The speed is limited at some range of sub-synchronous speed of the rotating magnetic field. Control speed by adjusting resistance value in the rotor circuit that occurs the efficiency of power are reduced, because of the slip energy is lost when it passes through the rotor resistance. The control system is designed to maintain efficiency of motor. Fuzzy logic control method is applied for self-tuning the system by keeping the speed constant and adjusting the rotor current appropriated to the load. The good transient response without overshoot can be obtained.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    An efficient algorithm for circuit partitioning
    (1999-12-01)
    Yodtean, Apiradee
    ;
    Choomchuay, Somsak
    ;
    Suzuki, Yasoji
    This paper describes an improved simulated annealing algorithm applied for graph balanced bipartitioning problem, in particular for circuit partitioning problem. The new algorithm has incorporated the idea and procedure required in a genetic algorithm Experiment results on industrial benchmark circuits show that the proposed algorithm is superior to a conventional simulated annealing algorithm in both cut cost and run time.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Robust PID×(n-2) stage PD cascade controller
    (1999-12-01)
    Kitti, Tirasesth
    ;
    Jongkol, Ngamwiwit
    ;
    Prasit, Julsereewong
    ;
    Thanit, Trisuwannawat
    ;
    Michihiko, Iida
    This paper presents a design technique for the two degree of freedom (2-DOF) control system using PID (Proportional-Integral-Derivative)×(n-2) stage PD as a cascade controller for a class of n<sup>th</sup> order plant. It is intended to satisfy both transient and steady state response specifications based on the root locus approach. This controller can be used instead of the conventional PID controller for the higher order plant to obtain better performance. The transfer function of a class of n<sup>th</sup> order plant should not include zeros, the poles of the plant should have negative real part. The overall system is approximated as a stable and robust second order system. The performances of the controlled system are satisfied by this design technique. Moreover, this technique can also be applied to the plant with small dead time. The cascade controller gain can be adjusted to meet faster responses with a little or no overshoot. Robustness properties given by this controller proposed in this paper have also been demonstrated by numerical examples.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    High frequency CMOS precision full-wave rectifier circuit
    (1999-12-01)
    Guntapong, Rojanakorn
    ;
    Riewruja, Vanchai
    ;
    Fongsamut, Chalermpan
    ;
    Kaewpoonsuk, Anucha
    A CMOS integrable circuit technique for the realization of full-wave precision rectifier circuit, which operates throughout in the current domain, is presented. The circuit achieves a wide dynamic range and a wide-band capability. The rectifying characteristic of the circuit exhibits a low distortion in the output signal at low level input signal, Simulation results demonstrating the circuit performance are included.