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Practical System (practical + system)
Selected AbstractsStrategic adaptation to change: A practical system for achieving breakthrough performanceGLOBAL BUSINESS AND ORGANIZATIONAL EXCELLENCE, Issue 3 2002Martin M. Stein One of the best ways to understand the value of and need for organizational learning is to begin by setting a goal. Then examine the organizational barriers to achieving it,and design the policies, programs, and practices that will overcome them. This process, properly sustained, can continuously upgrade an organization's core competencies and intellectual capital. People get energized, knowledge gets communicated and applied, and change becomes a challenge rather than a threat. © 2002 Wiley Periodicals, Inc. [source] Neural network-based adaptive control of piezoelectric actuators with unknown hysteresisINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2009Wen-Fang Xie Abstract This paper proposes a neural network (NN)-based adaptive control of piezoelectric actuators with unknown hysteresis. Based on the classical Duhem model described by a differential equation, the explicit solution to the equation is explored and a new hysteresis model is constructed as a linear model in series with a piecewise continuous nonlinear function. An NN-based dynamic pre-inversion compensator is designed to cancel out the effect of the hysteresis. With the incorporation of the pre-inversion compensator, an adaptive control scheme is proposed to have the position of the piezoelectric actuator track the desired trajectory. This paper has three distinct features. First, it applies the NN to online approximate complicated piecewise continuous unknown nonlinear functions in the explicit solution to Duhem model. Second, an observer is designed to estimate the output of hysteresis of piezoelectric actuator based on the system input and output. Third, the stability of the controlled piezoelectric actuator with the observer is guaranteed. Simulation results for a practical system validate the effectiveness of the proposed method in this paper. Copyright © 2008 John Wiley & Sons, Ltd. [source] Urination assessment after the removal of bladder catheter using a novel urination chartNURSING & HEALTH SCIENCES, Issue 3 2003Tomoko Owan rn, phd Abstract We investigated the difficulties involved in assessing post prostatectomy voiding according to 20 nurses working in urology and dermatology wards. Problems they encountered included completing a urination (frequency/volume) chart and performing an assessment. We constructed a hourly urination chart for basic nursing education in urinary incontinence. This was used for a 76-year-old male patient with hypertension and diabetes mellitus who underwent a prostatectomy. Urination was recorded for 17 consecutive days after catheter removal. Detailed pathological findings were more distinct in the hourly rather than daily recordings of voluntary micturition. Voluntary micturition appeared 12 h after catheter removal, but it was very scanty. After the onset of urination, frequency and amount of daily voluntary micturition was inversely related to incontinence during the 17 days after catheter removal. We drafted a set of urination recovery stages to enable the analysis of a patient's urination status. Nurses understood its importance and were able to reach a consensus on how to manage patients with postoperative incontinence. We have constructed a practical system for use by specialist urology nurses. [source] The long term evolution towards a new 3GPP* air interface standardBELL LABS TECHNICAL JOURNAL, Issue 4 2007Rainer Bachl The performance targets for the long term evolution (LTE) of the Universal Mobile Telecommunication System (UMTS) into a 4th generation system have been chosen to be very ambitious. While all of these targets may not be achievable in practice, they have served to motivate the decisions for a particular LTE design. Specifically, we discuss the choice of the multiple access scheme for LTE, provide details on the uplink and downlink transmission formats, analyze the benefits of multiple input multiple output (MIMO), and outline approaches for intercell interference mitigation. The trade-off between usage of MIMO spatial multiplexing and beamforming is shown for a practical system. The required signaling overhead is weighed against the performance improvements available from the additional information. Finally, some examples for the achievable physical layer performance are given. © 2007 Alcatel-Lucent. [source] Joint data detection and estimation of time-varying multipath rayleigh fading channels in asynchronous DS-CDMA systems with long spreading sequences,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2007Pei Xiao In this paper, we present a joint approach to data detection and channel estimation for the asynchronous direct-sequence code-division multiple access (DS-CDMA) systems employing orthogonal signaling formats and long scrambling codes. Our emphasis is placed on different channel estimation algorithms since the performance of a communication system depends largely on its ability to retrieve an accurate measurement of the underlying channel. We investigate channel estimation algorithms under different conditions. The estimated channel information is used to enable coherent data detection to combat the detrimental effect of the multiuser interference and the multipath propagation of the transmitted signal. In the considered multiuser detector, we mainly use interference cancellation techniques, which are suitable for long-code CDMA systems. Interference cancellation and channel estimation using soft estimates of the transmitted signal is also proposed in this paper. Different channel estimation schemes are evaluated and compared in terms of mean square error (MSE) of channel estimation and bit error rate (BER) performance. Based on our analysis and numerical results, some recommendations are made on how to choose appropriate channel estimators in practical systems. Copyright © 2006 AEIT [source] Multiuser detection techniques with decision statistics combining for layered space-time coded CDMA systemsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 4 2006Slavica Marinkovic This paper considers a low-complexity iterative multiuser detection/decoding algorithm in single user layered space-time coded (LST) systems and LST coded code division multiple access (CDMA) systems. We concentrate on the iterative multiuser receiver based on parallel interference cancellation (PIC) and compare it to the iterative PIC with the minimum means square error (MMSE) detection, as these two approaches seem to be most efficient in meeting the performance-complexity trade-off required by practical systems. In iterative PIC structures, a decision statistics bias severely limits the system performance for a large number of multiple access (MA) or multiple-input multiple-output (MIMO) interferers. A decision statistics combining (DSC) method, originally proposed for iterative PIC receivers in CDMA systems, is used to minimize the bias effect in space-time coded systems for iterative PIC receivers. Significant performance improvements have been confirmed with the iterative PIC receiver with DSC (PIC-DSC) relative to the standard iterative PIC receivers in LST systems for both flat and frequency selective fading channels. This advantage is retained in layered coded CDMA systems as well. The proposed iterative PIC-DSC detector approaches the performance of the much more complex iterative PIC-MMSE receiver. Copyright © 2006 AEIT. [source] Adaptive backstepping control for a class of time delay systems with nonlinear perturbationsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 3 2008Chang-Chun Hua Abstract The sliding mode control method has been extensively employed to stabilize time delay systems with nonlinear perturbations. Although the resulting closed-loop systems have good transient and steady-state performances, the designed controllers are dependent on the time delays. But one knows that it is difficult to obtain the precise delay time in practical systems, especially when it is time varying. In this paper, we revisit the problem and use the backstepping method to construct the state feedback controller. First, a coordinate transformation is used to obtain a cascade time delay system. Then, a linear virtual control law is designed for the first subsystem. The memoryless controller is further constructed based on adaptive method for the second subsystem with the uncertainties bounded by linear function. By choosing new Lyapunov,Krasovskii functional, we show that the system state converges to zero asymptotically. Via the proposed approach, we also discuss the case that the uncertainties are bounded by nonlinear functions. Finally, simulations are done to verify the effectiveness of the main results obtained. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||