1. Ming-Shing Hsieh, Din-Chang Tseng, Yong-Huai Huang, "iding digital watermarks using multiresolution wavelet transform ," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 875-882, Oct. 2001. Full Text Link
Abstract : In this paper, an image accreditation technique by embedding digital watermarks in images is proposed. The proposed method for the digital watermarking is based on the wavelet transform. This is unlike most previous work, which used a random number of a sequence of bits as a watermark and where the watermark can only be detected by comparing an experimental threshold value to determine whether a sequence of random signals is the watermark. The proposed approach embeds a watermark with visual recognizable patterns, such as binary, gray, or color image in images by modifying the frequency part of the images. In the proposed approach, an original image is decomposed into wavelet coefficients. Then, multi-energy watermarking scheme based on the qualified significant wavelet tree (QSWT) is used to achieve the robustness of the watermarking. Unlike other watermarking techniques that use a single casting energy, QSWT adopts adaptive casting energy in different resolutions. The performance of the proposed watermarking is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, median filtering, and incorporating attacks
2. Hong Ye, G.C. Walsh, L.G. Bushnell, "Real-time mixed-traffic wireless networks," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 883-890, Oct. 2001. Full Text Link
Abstract : In this paper we introduce a new protocol, prioritized carrier sense multiple access with collision avoidance, for real-time wireless local area networking. Wireless networks increasingly will be called upon to carry mixed traffic, some portion of which will be devoted to real-time control and monitoring. Our protocol, based upon the IEEE 802.11 wireless standard, mixes real-time traffic with standard multimedia data in a way which assures loop stability. Scheduling the real-time traffic is the primary issue considered. Under our framework, we propose and validate several new algorithms for dynamically scheduling the traffic of wireless networked control systems: constant penalty, estimated error order and lag first-order schemes. All algorithms are compared via simulation and the results show that dynamic scheduling algorithms achieve better system performance on average than static scheduling algorithms like fixed-order polling. The results of a real experiment involving two dryer plants and three IEEE 802.11 nodes are reported with static scheduling employed as it lower bounds the closed-loop behavior
3. Kit-Sang Tang, King-Tim Ko, S. Chan, E.W.M. Wong, "Optimal file placement in VOD> system using genetic algorithm," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 891-897, Oct. 2001. Full Text Link
Abstract : Advances in computing and networking are generating a significant demand for video-on-demand (VOD) applications. In this paper, the condition for minimum blocking probability of a VOD system is derived. The optimal load-sharing requirement in such a system is found so that the minimum blocking probability is achieved. A combination of genetic algorithm and modified bin-packing algorithm is then developed for the multimedia file placement exercise. It is demonstrated that a specified blocking probability can be achieved while the capacity usage is minimized simultaneously
4. Wan-De Weng, Wen Pin Yang, "The CPLD implementation of Viterbi algorithm in grand alliance ATSC systems," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 898-903, Oct. 2001. Full Text Link
Abstract : Digital television has become one of the most promising industries. The advanced television system is scheduled to totally replace the current television broadcasting system in the US. In this paper, we present the implementation and discussion of the trellis en/decoder in the grand alliance digital television system proposed by the Advanced Television System Committee (ATSC). In the paper, we use a relatively efficient way to realize the en/decoding circuit. The correctness of our design has also been demonstrated
5. K. Sengupta, Chi Chung Ko, "Scanning face models with desktop cameras," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 904-912, Oct. 2001. Full Text Link
Abstract : Generating face models of humans from video sequences is an important problem in many multimedia applications ranging from teleconferencing to virtual reality. Most practical approaches try to fit a generic face model in the two-dimensional image, and adjust the model parameters to arrive at the final answer. These approaches require the identification of specific landmarks on the face, and this identification routine may or may not be an automated process. In this paper, we present a method for deriving the three-dimensional (3-D) face model from a monocular image sequence, using a few standard results from the affine camera geometry literature in computer vision, and spline-fitting techniques adopted from the nonparametric regression literature in statistics. No prior knowledge of the camera calibration parameters and the shape of the face is required by the system, and the entire process requires no user intervention. The system has been successfully demonstrated to extract the 3-D face structure of humans in several image sequences
6. Chwan-Hwa Wu, J.D. Irwin, F.F. Dai, "Enabling multimedia applications for factory automation," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 913-919, Oct. 2001. Full Text Link
Abstract : Emerging multimedia communication and processing technologies enable many factory applications. However, these technologies are advancing at a prodigious pace. Therefore, designing, managing, and upgrading these networks within this fast-paced environment represents a formidable challenge. The various enabling technologies and the standards that control their use are the subject of this paper. Special emphasis is given to the use of these technologies to support developments on the factory floor. This strategy involves the use of video, audio, and data communications, as well as the inherent processing involved. The role that local area networks and the Internet play in the development of future factory applications is also discussed
7. Zhaojin Han, T.S. Denney, "Incremental Fourier interpolation of 2-D fractional Brownian motion ," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 920-925, Oct. 2001. Full Text Link
Abstract : This paper presents a new method to interpolate two-dimensional fractional Brownian motion (fBm), fBm interpolation can be used in multimedia applications such as landscape synthesis or zooming into a synthetic scene, where the objective is to generate an fBm field that passes through a sparse set of known points. The fBm interpolation problem differs from standard image interpolation because noise must be added to the interpolated points to obtain an interpolated image with the proper second-order statistics. Our interpolation method is based on the first-order increments of both the original fBm and interpolated fBm. These increments are stationary and yield interpolation equations with a Toeplitz-block-Toeplitz structure which can be approximated by a circulant-block-circulant matrix. By taking advantage of fast Fourier transform, the computational complexity is O(N2log2N) for N×N image interpolation. Simulation shows this method achieves good second-order statistics, even for small-size images
Drive Control
8. Rong-Jong Wai, "Total sliding-mode controller for PM synchronous servo motor drive using recurrent fuzzy neural network," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 926-944, Oct. 2001. Full Text Link
Abstract : In this paper, the dynamic responses of a recurrent-fuzzy-neural-network (RFNN) sliding-mode-controlled permanent-magnet (PM) synchronous servo motor are described. First, a newly designed total sliding-mode control system, which is insensitive to uncertainties, including parameter variations and external disturbance in the whole control process, is introduced. The total sliding-mode control comprises the baseline model design and the curbing controller design. In the baseline model design, a computed torque controller is designed to cancel the nonlinearity of the nominal plant. In the curbing controller design, an additional controller is designed using a new sliding surface to ensure the sliding motion through the entire state trajectory. Therefore, in the total sliding-mode control system, the controlled system has a total sliding motion without a reaching phase. Then, to overcome the two main problems with sliding-mode control, i.e., the assumption of known uncertainty bounds and the chattering phenomena in the control effort, an RFNN sliding-mode control system is investigated to control the PM synchronous servo motor. In the RFNN sliding-mode control system, an RFNN bound observer is utilized to adjust the uncertainty bounds in real time. To guarantee the convergence of tracking error, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the RFNN. Simulated and experimental results due to periodic step and sinusoidal commands show that the dynamic behaviors of the proposed control systems are robust with regard to uncertainties
9. Ho Seong Lee, "Controller optimization for minimum position error signals of hard disk drives," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 945-950, Oct. 2001. Full Text Link
Abstract : In order to reduce the position error signal (PES) and track misregistration (TMR) of disk drives, it is generally believed that the bandwidth of a disk drive servo system has to be increased. However, increase of the bandwidth is limited by available sampling frequency and mechanical resonances of a head-disk assembly. Hence, for a given servo-mechanical system, optimization of a servo controller is a crucial and economical way to get the best TMR performance. In this paper, optimization of a servo controller that yields minimum PES is presented. The equivalent position-mode disturbance is estimated by the error transfer function inversion method. The estimated disturbance is injected into the servo system to evaluate PES. The optimization process will select the best controller that minimizes PES under the specified constraints. It has been demonstrated that the minimization has been achieved by shaping the error transfer function rather than increase of the servo bandwidth, PES reduction has been confirmed by simulation and experiments
10. P. Melin, O. Castillo, "Intelligent control of complex electrochemical systems with a neuro-fuzzy-genetic approach," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 951-955, Oct. 2001. Full Text Link
Abstract : This paper describes different hybrid approaches for controlling the battery charging process. The hybrid approaches combine soft computing techniques to achieve the goal of controlling the temperature of the battery during the electrochemical charging process. We have reduced the time required for charging a battery with the use of fuzzy logic, neural networks, and genetic algorithms. In the neuro-fuzzy-genetic approach, neural networks are used for modeling the electrochemical process, fuzzy logic is used for controlling the process, and genetic algorithms are used to optimize the fuzzy system
11. Bor-Jehng Kang, Chang-Ming Liaw, "A robust hysteresis current-controlled PWM inverter for linear PMSM driven magnetic suspended positioning system," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 956-967, Oct. 2001. Full Text Link
Abstract : Hysteresis current-controlled pulsewidth modulation (PWM) is very robust but it possesses nonconstant switching frequency, and it is difficult to use for high-performance position servo applications. This paper presents a robust hysteresis current-controlled PWM scheme for a magnetic suspended positioning system driven by an inverter-fed linear permanent-magnet synchronous motor having improved performance in these two areas. In the proposed control scheme, the conventional hysteresis PWM mechanism is augmented by a robust harmonic spectrum-shaping controller. The error signal, which represents the switching frequency deviated from the set one, is detected using a notching filter inverse model. Then, the current command is adjusted by a robust compensation signal. The hysteresis band can be equivalently varied to let the dominant harmonic frequency of inverter output be constant, wherein the frequency can easily be changed by tuning the center frequency of the notch filter. The gating signal of switches is not needed to be sensed for making the proposed control. The constant-frequency control performance yielded by the proposed controller is rather insensitive to the system disturbances and the neutral voltage variation due to isolated Y connection. Through applying the proposed PWM inverter, satisfactory position control requirements can be achieved by properly setting the dominant harmonic frequency according to the electromechanical model of the positioning system
12. Chi-Huang Lu, Ching-Chih Tsai, "Adaptive decoupling predictive temperature control for an extrusion barrel in a plastic injection molding process," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 968-975, Oct. 2001. Full Text Link
Abstract : This paper presents an adaptive decoupling temperature control for an extrusion barrel in a plastic injection molding process. After establishing a stochastic polynomial matrix model of the system, a corresponding decoupling system representation was then developed. The decoupling control design was derived based on the minimization of a generalized predictive performance criterion. The set-point tracking, disturbance rejection, and robustness capabilities of the proposed method can be improved by appropriate adjustments to the tuning parameters in the criterion function. A real-time control algorithm, including the recursive least-squares method, is proposed which was implemented using a digital signal processor TMS320C31 from Texas Instruments. Through the experimental results, the proposed method has been shown to be powerful under set-point changes, load disturbances, and significant plant uncertainties. The proposed control law is shown to be less computational and more effective than other well-known multivariable control strategies, and more powerful than single-loop temperature-zone control policies
13. Qing-Guo Wang, Qiang Bi, Yong Zhang, "Partial internal model control," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 976-982, Oct. 2001. Full Text Link
Abstract : Internal model control (IMC) is a well-known and effective control scheme. However, when unstable processes are concerned, the original IMC structure cannot be directly used for control system implementation. In this paper, a new scheme called partial internal model control (PIMC) is proposed, which is capable of controlling both stable and unstable processes. In PIMC, a process model is expressed as the sum of the stable and antistable parts and only the stable part of the process model is used as the internal model. The process stable part is canceled by the internal model and the remaining antistable part is stabilized and controlled with a primary controller, which is usually a PID-type regulator when the antistable part is of a low order. Various properties of a PIMC system such as internal stability and robust stability are analyzed. The design of PIMC is discussed in detail. Various simulation examples are included for illustration and a real-time implementation on a motor system is presented
14. Chunshien Li, Chun-Yi Lee, "Fuzzy motion control of an auto-warehousing crane system," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 983-994, Oct. 2001. Full Text Link
Abstract : Fuzzy motion control of an auto-warehousing crane system is presented in this paper. Using the concept of linguistic variable, a fuzzy logic controller (FLC) can convert the knowledge and experience of an expert into an automatic control strategy. The designed FLC with a rule base and three sets of parameters is used to control the crane system in x, y, and z directions. The unloaded weight and the fully loaded weight of the crane system in discussion are 1.35×104 kg and 1.5×104 kg, respectively. For various loading conditions and varying distances, the FLC still controls the crane system very well with positioning accuracy less than 2×10 -3 m for all directions. The distance-speed reference curve for control of the crane system is designed to meet the engineering specifications of motion such as acceleration, deceleration, maximum speed, and creep speed in each direction, and is generated automatically according to varying distance. The method for designing the distance-speed reference curve can make the crane move at relatively high speed to approach the target position. Simulations of the motion control in the three directions are demonstrated
15. G. Garcera, M. Pascual, E. Figueres, "Robust average current-mode control of multimodule parallel DC-DC PWM converter systems with improved dynamic response," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 995-1005, Oct. 2001. Full Text Link
Abstract : This paper presents a novel average current-mode control (ACC) strategy for the control of multimodule parallel pulsewidth modulation DC-DC converters, which represents a drastic improvement over conventional ACC. This new method consists of the addition of an auxiliary controller into the control loop, besides the current and voltage regulators. The reference-model-based auxiliary controller improves the robustness of the ACC dynamics in buck-derived distributed power systems, preserving loop gain crossover frequency and stability margins over significant changes of the number of connected modules, the load and the line voltage. Moreover, this control scheme shows much better disturbance rejection properties, i.e., closed-loop output impedance and audiosusceptibility, than conventional ACC. From a control theory point of view robust performance is achieved, preserving stability. A multimodule buck prototype has been experimentally tested with different numbers of modules on stream, line, and load conditions, including discontinuous conduction mode. Measurements of the small-signal frequency response of the converter have been carried out, showing the improvement achieved by the proposed control scheme. The empirical large-signal response of the converter under load steps is also shown in order to validate the concept
Power Electronics
16. Kyo-Beum Lee, Joong-Ho Song, I. Choy, Ji-Yoon Yoo, "Improvement of low-speed operation performance of DTC> for three-level inverter-fed induction motors," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 1006-1014, Oct. 2001. Full Text Link
Abstract : A direct torque control algorithm for three-level inverter-fed induction motors is presented. Basic voltage selection methods similar to a two-level inverter provoke some problems such as stator-flux drooping phenomenon and undesirable torque control deterioration appeared, especially at low-speed operation. To overcome these problems, an algorithm with the basic switching sectors subdivided and intermediate voltage vectors applied is proposed in this paper. This algorithm basically considers applications in which direct torque-controlled induction motors are fed by three-level inverters with maximum switching frequency lowered around 1 kHz. An adaptive observer is also employed to bring better responses at the low-speed operation, by estimating some state variables and motor parameters which take a deep effect on the performance of the low-speed operation. Simulation and experiment results verify effectiveness of the proposed algorithm
17. Jooho Song, Joong-Ho Song, I. Choy, Ju-Yeop Choi, "Improving crest factor of electronic ballast-fed fluorescent lamp current using pulse frequency modulation," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 1015-1024, Oct. 2001. Full Text Link
Abstract : In case where electronic ballast employing a valley-fill passive power-factor correction (PFC) circuit is used for feeding fluorescent tamps, a new method to reduce crest factor of the lamp current is studied in this paper. It is known that a 50% valley-fill passive PFC provided for high input power factor results in undesirable value of crest factor of the fluorescent lamp current, In order to reduce crest factor to a lower value, a pulse frequency modulation technique based on the waveform of the DC-link voltage which is predetermined by the passive PFC circuit is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed. Several simulation and experiment results illustrate the Effectiveness of the proposed control scheme
Emerging Technologies
18. A. Willig, A. Wolisz, "Ring stability of the PROFIBUS token-passing protocol over error-prone links," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 1025-1033, Oct. 2001. Full Text Link
Abstract : The PROFIBUS is a well-known and widely used fieldbus. On the medium access control layer, it employs a token-passing protocol where all active stations form a logical ring on top of a broadcast medium. This protocol is designed to deliver real-time data transmission services in harsh industrial environments. A necessary prerequisite for timeliness and quality of service is the ring membership stability of the logical ring in the presence of transmission errors, since only ring members are allowed to transmit data. In this paper, the ring membership stability under high error rates and using different error models is analyzed. The choice of the error behavior is in turn inspired by properties of possible future transmission technologies, e.g., wireless LANs. It is shown that the protocol has serious stability problems. To attack these problems, two changes to the protocol and its parameters are proposed, which can be implemented in a purely local manner. We show that they significantly improve ring stability
Signal Processing
19. M. Kamiya, H. Ikeda, S. Shinohara, "Analog data transmission through plastic optical fiber in robot with compensation of errors caused by optical fiber bending loss," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 1034-1037, Oct. 2001. Full Text Link
Abstract : A new type of analog data transmission system using a plastic fiber is proposed, where a direct intensity modulation scheme has been employed together with a differential amplifier to compensate for the transmission error caused by the optical fiber bending loss. This system was experimentally applied to transmit analog data of dimensions detected by the displacement sensor attached to the robot arm tip to the robot basement through the plastic optical fiber installed in the robot arm body
Letter to the Editor
20. J.R. Heredia, F. Perez Hidalgo, J.L. Duran Paz, "Sensorless control of induction motors by artificial neural networks," Trans. on Industrial Electronics, vol. 48, no. 5, pp. 1038-1040, Oct. 2001. Full Text Link
Abstract : In this letter, we propose a voltage-source inverter control working in the open loop of an induction motor measuring the stator current and using an artificial neural network. This technique has the mission to estimate the speed and torque of the rotor without using sensors. With this, a simple and cheap method of control is obtained, with as much precision and robustness as other more complex ones