Search results for "Control"
showing 10 items of 13168 documents
Effects ofBacillus thuringiensisCry1Ab and Cry3Aa endotoxins on predatory Coleoptera tested through artificial diet-incorporation bioassays
2009
AbstractTraditional approaches to studying the effects of genetically modified (GM) crops on beneficial insects involve either field assays, comparing insect population levels between control and GM crops or tritrophic bioassays with contaminated insects – usually larvae or eggs of Lepidoptera – as preys. Here, we report the results of a bioassay using an artificial diet, suitable for predatory Coleoptera, to supplyBacillus thuringiensis(Bt) solubilized Cry1Ab and Cry3Aa as well as trypsin-activated Cry1Ab toAtheta coriariaandCryptolaemus montrouzieriadults and young larvae ofAdalia bipunctata. Water, solubilization buffer and trypsin-treated solubilization buffer were used as controls. In …
Middleware with QoS Support to Control Intelligent Systems
2008
This paper presents the architecture of a middleware for control component-based distributed systems. The fundamental idea underlying this architecture is the use of a hierarchical communications structure called "logical namespace tree" and a structured set of control processes interconnected, called "logical sensors graph". This architecture is named frame sensor adapter control (FSA-Ctrl). The aim of FSA-Ctrl is to provide a simple interface to specify the control actions and ensure a communication with some specified QoS parameters restrictions. In this architecture both systems, communication and control, manages the QoS policies. The communication system is based on the data distribut…
FPGA Implementation of an Adaptive Filter Robust to Impulsive Noise: Two Approaches
2011
Adaptive filters are used in a wide range of applications such as echo cancellation, noise cancellation, system identification, and prediction. Its hardware implementation becomes essential in many cases where real-time execution is needed. However, impulsive noise affects the proper operation of the filter and the adaptation process. This noise is one of the most damaging types of signal distortion, not always considered when implementing algorithms, particularly in specific hardware platforms. Field-programmable gate arrays (FPGAs) are used widely for real-time applications where timing requirements are strict. Nowadays, two main design processes can be followed for embedded system design…
Intelligent Adaptive Motion Control for Ground Wheeled Vehicles
2014
In this paper a new intelligent adaptive control is applied to solve a problem of motion control of ground vehicles with two independent wheels actuated by a differential drive. The major objective of this work is to obtain a motion control system by using a new fuzzy inference mechanism where the Lyapunov’s stability can be assured. In particular the parameters of the kinematical control law are obtained using an intelligent Fuzzy mechanism, where the properties of the Fuzzy maps have been established to have the stability above. Due to the nonlinear map of the intelligent fuzzy inference mechanism (i.e. fuzzy rules and value of the rule), the parameters above are not constant, but, time a…
Optimal Flight Path Determination in Turbulent Air: A Modified EKF Approach
2018
By using the Extended Kalman Filter an accurate path following in turbulent air is performed. The procedure employs simultaneously two dierent EKFs: the rst one estimates disturbances, the second one aords to determine the necessary controls displacements for rejecting those ones. To tune the EKFs an optimization algorithm has been designed to automatically determine Process Noise Covariance and Measurement Noise Covariance matrices. The rst lter, by using instrumental measurements gathered in turbulent air, estimates wind components. The second one obtains command laws able to follow the desired ight path. To perform this task aerodynamic coecients have been modied. Such a procedure leads …
Using adaptive fuzzy-neural control to minimize response time in cluster-based web systems
2005
We have developed content-aware request distribution algorithm called FARD which is a client-and-server-aware, dynamic and adaptive distribution policy in cluster-based Web systems. It assigns each incoming request to the server with the least expected response time. To estimate the expected response times it uses the fuzzy estimation mechanism. The system is adaptive as it uses a neural network learning ability for its adaptation. Simulations based on traces from the 1998 World Cup show that when we consider the response time, FARD can be more effective than the state-of-the-art content-aware policy LARD.
Distributed Adaptive Control for Asymptotically Consensus Tracking of Uncertain Nonlinear Systems With Intermittent Actuator Faults and Directed Comm…
2019
In this article, we investigate the output consensus tracking problem for a class of high-order nonlinear systems with unknown parameters, uncertain external disturbances, and intermittent actuator faults. Under the directed topology conditions, a novel distributed adaptive controller is proposed. The common time-varying trajectory is allowed to be totally unknown by part of subsystems. Therefore, the assumption on the linearly parameterized trajectory signal in most literature is no longer needed. To achieve the relaxation, extra distributed parameter estimators are introduced in all subsystems. Besides, to handle the actuator faults occurring at possibly infinite times, a new adaptive com…
Adaptive dual control in one biomedical problem
2003
In this paper, the following biomedical problem is considered. People are subjected to a certain chemotherapeutic treatment. The optimal dosage is the maximal dose for which an individual patient will have toxicity level that does not cross the allowable limit. We discuss sequential procedures for searching the optimal dosage, which are based on the concept of dual control and the principle of optimality. According to the dual control theory, the control has two purposes that might be conflicting: one is to help learning about unknown parameters and/or the state of the system (estimation); the other is to achieve the control objective. Thus the resulting control sequence exhibits the closed…
Schedulability analysis of window-constrained execution time tasks for real-time control
2003
Feasibility tests for hard real-time systems provide information about the schedulability of a set of tasks. However, this information is a yes or no answer whether the task set achieves the test or not. From the system design point of view, it would be useful to have more information, for example, how much can one vary some task parameters, such as computation time, without jeopardizing the system feasibility. The aim of the work is to provide a method to determine how much a task can increase its computation time, maintaining the system feasibility under a dynamic priority scheduling. This extra time can be determined not only in all the task activations, but in n of a window of m task in…
Stability Analysis of a Linear Parameter Varying Adaptive Output Feedback Control System
2021
Abstract Output feedback control systems often require an adaptive filter for properly shaping the loop transfer function, as certain system plant parameters may be uncertain or varying. This renders the overall closed loop to a linear parameter varying (LPV) system, for which the stability analysis is challenging due to non-trivial dynamics of the adaptation law. This paper develops a stability analysis technique of a feedback controlled oscillatory system. A polytopic overapproximation of the parameter set together with the feasibility of certain LMIs guarantees asymptotic stability of the closed loop. The varying filter parameter is only required to be lower and upper bounded, where the …