Search results for "Server"
showing 10 items of 586 documents
Interaction risk with proton pump inhibitors in general practice: significant disagreement between different drug-related information sources.
2006
Aims To compare information on drug–drug interactions (DDIs) reported on two standard drug-related information sources (Summary of Product Characteristics and Drugdex system by Micromedex), by assessing the prevalence and predictors of potential DDI with proton pump inhibitors (PPIs) in general practice. Methods From the ‘Caserta-1’ Local Health-Service database, 156 general practitioners (GPs) were recruited. From more than 180 000 individuals registered on their lists, we selected patients receiving co-prescription of PPI and medications at interaction risk, according to the Italian Summary of Product Characteristics (SPC) of PPI and Drugdex information, during the year 2003. Thereafter, …
Classical electromagnetic radiation in noninertial reference frames
1991
Customarily electromagnetic radiation is defined with reference to some inertial laboratory frame. But such a definition is too narrow to be applicable to questions concerning accelerated observers,e.g. why an accelerated observer does not receive radiation from a co-accelerating charge. It is shown in this paper that a radiation concept introduced for inertial observers by Rohrlich and Teitelboim allows an extension to noninertial (accelerating and rotating) reference frames in a natural way. The generalized concept is explicitly dependent on the proper acceleration and the rotation of the observer’s laboratory frame. The case of radiation due to an accelerated point charge is treated in f…
The electromagnetic field of an accelerated charge in the proper reference frame of a noninertial observer
1989
The Lienard-Wiechert formulae for the electric and magnetic fields of an accelerated charge moving along an arbitrary world-line are generalized so that they can be applied by noninertial observers using accelerating and rotating reference frames. For this purpose, a relativistic coordinate-independent formalism suggested by DeFacio, Dennis and Eetzloff is extended to the description of all kinematical aspects required in the theory of the retarded fields of a point charge. The generalized Lienard-Wiechert formula is applied to a number of special situations, demonstrating that it allows a lucid and concise treatment of a number of subtle problems such as the role of the «relativity of acce…
Robust Active Disturbance Rejection Control of Induction Motor Systems Based on Additional Sliding-Mode Component
2017
This paper deals with motion control systems with induction motor, subject to severe requirements on both dynamics and steady-state behavior. The proposed control methodology could be viewed as an advancement of the standard field oriented control. It consists of two control loops, i.e., the rotor flux and the speed control loops, designed using the active disturbance rejection control method, with the aim to cope with both exogenous and endogenous disturbances, which are estimated by means of two linear extended state observers and then compensated. Moreover, with the aim of achieving total robustness, a sliding-mode based component is designed, in order to take into account disturbance es…
Racecar Longitudinal Control in Unknown and Highly-Varying Driving Conditions
2020
This paper focuses on racecar longitudinal control with highly-varying driving conditions. The main factors affecting the dynamic behavior of a vehicle, including aerodynamic forces, wheel rolling resistance, traction force resulting from changing tire-road interaction as well as the occurrence of sudden wind gusts or the presence of persistent winds, are considered and assumed to have unknown models. By exploiting the theory on delayed input-state observers and using measurement data about the vehicle and wheel speeds, a dynamic filter that allows the online reconstruction of the above-mentioned unknown time-varying quantities is derived. Moreover, by exploiting the notion of effective tir…
Observer-Based Robust Control for Hydraulic Velocity Control System
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/689132 Open access This paper investigates the problems of robust stabilization and robust control for the secondary component speed control system with parameters uncertainty and load disturbance. The aim is to enhance the control performance of hydraulic system based on Common Pressure Rail (CPR). Firstly, a mathematical model is presented to describe the hydraulic control system. Then a novel observer is proposed, and an observed-based control strategy is designed such that the closed-loop system is asymptotically stable and satisfies …
Adaptive real-time estimation on road disturbances properties considering load variation via vehicle vertical dynamics
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http:/dx.doi.org/10.1155/2013/283528 Open Access Vehicle dynamics are directly dependent on tire-road contact forces and torques which are themselves dependent on the wheels' load and tire-road friction characteristics. An acquisition of the road disturbance property is essential for the enhancement of vehicle suspension control systems. This paper focuses on designing an adaptive real-time road profile estimation observer considering load variation via vehicle vertical dynamics. Firstly, a road profile estimator based on a linear Kalman filter is proposed, which has g…
Fault Detection of Networked Control Systems Based on Sliding Mode Observer
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also availeble from the publisher at: http://dx.doi.org/10.1155/2013/506217 Open Access This paper is concerned with the network-based fault detection problem for a class of nonlinear discrete-time networked control systems with multiple communication delays and bounded disturbances. First, a sliding mode based nonlinear discrete observer is proposed. Then the sufficient conditions of sliding motion asymptotical stability are derived by means of the linear matrix inequality (LMI) approach on a designed surface. Then a discrete-time sliding-mode fault observer is designed that is capable of guaranteeing the…
Neural based MRAS sensorless techniques for high performance linear induction motor drives.
2010
This paper proposes a neural based MRAS (Model reference Adaptive System) speed observer suited for linear induction motors (LIM). Starting from the dynamical equation of the LIM in the synchronous reference frame in literature, the so-called voltage and current models of the LIM in the stationary reference frame, taking into consideration the end effects, have been deduced. Then, while the inductor equations have been used as reference model of the MRAS observer, the induced part equations have been discretized and rearranged so to be represented by a linear neural network (ADALINE). On this basis, the so called TLS EXIN neuron has been used to compute on-line, in recursive form, the machi…
IBM Intelligent Bricks project—Petabytes and beyond
2006
This paper provides an overview of the Intelligent Bricks project in progress at IBM Research. It describes common problems faced by data center operators and proposes a comprehensive solution based on brick architectures. Bricks are hardware building blocks. Because of certain properties, defined here, scalable and reliable systems can be built with collections of identical bricks. An important feature is that brick-based systems must survive the failure of any brick without requiring human intervention, as long as most bricks are operational. This simplifies system management and allows very dense and very scalable systems to be built. A prototype storage server in the form of a 3 × 3 × 3…